Kem Lib.
Agrio. Dept. LIBRARY

OF THE

University of California.

GIFT OF

U. S, Sunt, of Documents.
Class

Issued September f>. 1908.

U. S. DEPARTMENT OF AGRICULTURE,

BUREAU OF CHEMISTRY BULLETIN No. 114,

H W. YVILKY, Chief of Bureau.

MEAT EXTRACTS AND SIMILAR
PREPARATIONS,

CsCLl 'DING STUDIES OF THE METHODS
OF ANALYSIS EMPLOYED.

BY

W. I). BKJELOW,

CHIEF, DIVISION' OF FOODS,
AND

F. (\ COOK,

PHYSIOLOGICAL CHEMIST.

WASHINGTON:

OOYi: RXMEXT PkINTIXC OFFICE

1 9Q8.

ORGANIZATION OF BUREAU OF CHEMISTRY.

H. W. Wiley, Chemist and Chief of Bureau,
W. D. Bigelow, Assistant Chief of Bureau.
F. L. Dunlap, Associate Chemist.
F. B. Linton, Chief Clerk.

Division of Foods:

W. D. Bicelow, Chief.
Washington Food Inspection Laboratory —

L. M. Tolman, Chief.
Chief Food and Drug- Inspector:

Walter G. Campbell.
Food and Drug Inspection Laboratories:

New York, R. E. Doolittle. Chief.

Boston, B. H. Smith, Chief.

Philadelphia, C. -S. Brinton. Chief.

Chicago. A. L. Winton. Chief.

New Orleans; 0, W. Harrison, Chief,

San Francisco, R. A. Gould, Chief.

St. Paul, A. S. Mitchell, Chief.

Detroit, H. L. Schii.tz. Chief.

Savannah. [Not appointed.]

Seattle. |X<>t appointed.]

Buffalo. W. L. Dubois, Chief.

Kansas City. [Not appointed.]

Denver. A. B. Leach. Chief.

Galveston. | Not appointed. ]

Portland,. Qireg. [Not appointed'.]

Cincinnati. [Not appointed..]
Sugar Laboratory:

A. II. B ryan, in charge.
Dairy Laboratory:

G. E. Patrick, ( 'hi<f.
Miscellaneous Laboratory:

J. K. Haywood, Chief.
Division of Drugs:

L. F. Kehleu. Chief.
Contracts Laboratory:

P. H. Walker. Chief.
Leather and Paper Laboratory:

F. P. Vkitih. Chief.
Microchemical Laboratory:

15. J. Howard, Chief.
Special Investigations:

Physiological < 'hemlstry —

Animal physiology, F. C. WEBER, in charge.

Vegetable physiology, J. A. L/B Clerc, in charge.
Bacteriological Chemistry —

(I. \V. SriLBp, Jr., in charge, Washington.

M. K. pENNTNGtofN (food research), yn. charge, Philadelphia.
Enologkal Chemistry —

W. B. Al wood, in charge, Charlottesville, Va.
Nitrogen Section —

T. C. Trescot, in charge.

• 1 *

Issued September 5, 1908.

U. S. DEPARTMENT OF AGRICULTURE,

BUREAU OF CHEMISTRY— BULLETIN No. 114.

H. W. WILEY, Chief of Bureau.

MEAT EXTRACTS AND SIMILAR
PREPARATIONS,

INCLUDING STUDIES OF THE METHODS
OF ANALYSIS EMPLOYED.

BY

W. D. BIGELOW,

CHIEF, DIVISION OF FOODS,

AND

F. C. COOK,

PHYSIOLOGICAL CHEMIST.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.

1908.

LETTER OF TRANSMITTAL

U. S. Department of Agriculture,

Bureau of Chemistry,
Washington, B.C., October 19, 1907.
Sir: I have the honor to transmit herewith the results of a chem-
ical study of various preparations made from meat, and some sub-
stances used to adulterate such products. In addition, comments
on the nutritive value of meat extracts and similar products have
been compiled from the literature of the subject. The wide use of
preparations of this nature by invalids and others seeking a con-
centrated nutritious food rather than a stimulant, and the fact that
but little is generally known of the actual composition of these prod-
ucts, make it advisable to publish the information obtained in the
course of these studies, which were primarily conducted for the estab-
lishment of standards.

I recommend that this manuscript be published as Bulletin 114 of
the Bureau of Chemistry.

Respectfully, H. W. Wiley,

Chief of Bureau.
Hon. James Wilson,

Secretary of Agriculture.

CONTENTS.

Page.

Chemical examination 7

Objects of the investigation 7

Description of samples 7

Comment by manufacturers 8

Meat extracts 12

Tentative standards 12

Methods of preparation 13

Solid meat extracts 14

Fluid meat extracts 15

Meat juices 18

Tentative standard 18

Discussion of results 18

Yeast extracts 20

Manufacture and use of yeast preparations 20

Methods of detection 21

Result of tests 21

Miscellaneous preparations 24

Classification 24

Discussion of results 25

Methods of analysis and their discussion 28

Preparation of sample 28

Moisture 28

Ash 28

Separation of organic and inorganic phosphorus 31

Acidity 31

Nitrogenous bodies 32

Classes of nitrogenous constituents and general methods of separation . . - 32

Insoluble and coagulable proteids 33

Proteoses and peptones 34

Gelatin 35

General discussion '. 35

Experimental work on methods 36

Total meat bases 38

Kreatin and kreatinin 39

Application of kreatinin test to meat extracts 39

Application of kreatinin test to tannin-salt filtrate 40

Xanthin bases 40

Ammonia 41

Succinic acid 41

Ether extract 42

Glycerol 42

Nitrates 43

Undetermined matter 44

Historical note on nutritive values 44

Gelatin 44

Meat extracts and juices 48

Conclusion 54

5

MEAT EXTRACTS AND SIMILAR PREPARATIONS, IN-
CLUDING STUDIES OF THE METHODS OF ANALYSIS
EMPLOYED.

CHEMICAL EXAMINATION.
OBJECTS OF THE INVESTIGATION.

For several years past the Division of Foods of the Bureau of
Chemistry has examined many of the meat extracts and so-called
meat juices. During the winter of 1905-6 a complete analysis of
more than thirty meat preparations was made. While the work
was in progress, several questions were raised which demanded
further study and consequently delayed the publication of the results.

The object of the investigation was to determine the condition
and quality of meat preparations, many of which are widely adver-
tised and highly recommended for invalids. The need of standards
for judging the merits of such preparations is evident, and the fact
that complete analyses of American meat preparations are not
available makes the publication of the results obtained desirable.
The tentative standards for meat extracts and meat juices, peptones,
and gelatin, as prepared by the Committee on Food Standards of
the Association of Official Agricultural Chemists, are given under the
appropriate captions.

DESCRIPTION OF SAMPLES.

The samples which were analyzed in this investigation were pur-
chased on the retail market in the winter of 1905-6 and represent the
market conditions prior to the passage of the meat-inspection act by
Congress June 30, 1906, and the enforcement of the same by the
Bureau of Animal Industry. It is well known that products of this
class vary somewhat from year to year, and, moreover, different
results may be obtained on the same sample by the application of
different methods. As the same treatment was given to all of the
preparations included in this report their relative values are fairly
indicated. In connection with the descriptive table are given such
comments as the manufacturers or agents of the various prepara-
tions offered when the analyses were submitted to them.

7

MEAT EXTRACTS.

Table I. — Description of samples analyzed.
SOLID MEAT EXTRACT-(SEE TABLE II).

Serial

num- • Name of preparation,
ber. I

Manufacturer.

15867

" Rex" Brand Beef Extract

The Cudahy Packing Company, Omaha, Nebr.
Liebig's Extract of Meat Company, Antwerp, Belgium.

(Agents, Corneille, David & Co., 120 Hudson street,

New York, N. Y.)

15868

15869

16048
16049
16060

Libbv, McNeill and Libbv, Chicago, 111.

Beef Extract, Coin Special

G. H. Hammond Company, Chicago, 111.

FLUID MEAT EXTRACTS— (SEE TABLE IV).

15964
15965
15966
15977
15979
15990
15991

Concentrated Fluid Beef Extract

Beef Juice

Meat Juice

Vigoral

" Rex" Fluid Beef Extract

Fluid Extract of Beef

Fluid Beef Jelly

Armour and Company. Chicago, 111.
John Wyeth and Brother, Philadelphia, Pa.
Valentine's Meat Juice Company, Richmond, Va.
Armour and Company, Chicago, 111.
The Cudahy Packing Company, Omaha, Nebr.
Cibils Company, Importers, New York, N. Y.
The Mosquera-Julia Food Company, Detroit, Mich.
(Agents, Parke, Davis & Co.)

MISCELLANEOUS PREPARATIONS— (SEE TABLE IX).

15911
15963

15976
16040

16044
15870
15908
15909
15988
15989

16038

16043
15978

16042

15910
16037

16039
16041

Bouillon Capsules

Bovril, Seasoned

Beef Jelly, Mosquera Extract of Beef.

Essence of Beef

Predigested Beef

Soluble Beef

Bovox Essence of Beef

Johnson's Fluid Beef

American Brand Extract of Beef

Bovinine Concentrated Beef

Essence of Mutton

Liquid Food (extract of beef , mutton,

and fruits).
Maggi's Bouillon

Peptonized Beef. Rose

Beef Extract and Vegetable Tablets. .
Leube-Rosenthal's Beef Solution

Malted Meat Extract of Beef

Beef Peptonoids

Royal Specialty Company, New York, N. Y.

Bovril (Ltd.), London, England. (Park and Tilford,

agents, New York, N. Y.)
The Mosquera-Julia Food Company, Detroit, Mich.

(Agents, Parke, Davis & Co.)
Brand and Company (Ltd.). Mayfair, Vauxhall, S. W.

London. (Fougera Company, agents, New York

N. Y.)
II. K. Mulford Company. Philadelphia, Pa.
Armour and Company. Chicago, 111.
The Bovox Company. Boston, Mass.
Bovril (Ltd.), Montreal, Canada.
American Beef Extract Company, Boston, Mass.
The Bovinine Company, 75 W. Houston street, New

York.
The London Essence Company, London, England.

(W. B. llurd and Company, 18 Cedar street, New

York, N. Y.)
Murdock Liquid Food Company, Boston, Mass.

The Maggi Company, Kempttal, Switzerland. (J. P.

Smith and Company, agents, 90 Hudson street, New

York, N. Y.)
P. B. Rose. (General agents, Chapman, Green and

Company, Chicago, 111.)
Armour and Company. Chicago, 111.
Ph. Rudisch. (Cheppe and Schur, agents, Third avenue

and 60th street, New York, N. Y.)
American Malted Meat Company, South Milwaukee,

Wis.
The Arlington Chemical Company, Yonkers, N. Y.

COMMENT BY MANUFACTURERS.

The analyses of the commercial products examined were referred
to the manufacturers or their agents, and the following extracts from
the replies received are submitted.

The letters addressed to the American Beef Extract Company,
Boston, Mass.; American Malted Meat Company, South Milwaukee,
Wis.; Cibils Company, New York City; W. B. Hurd and Company, 18
Cedar street, New York City, and to Chapman, Green and Company,
Chicago, 111., were returned unclaimed. The following manufacturers

COMMENT BY MANUFACTURERS. 9

replied, but offered no criticism of the analyses: The Bovinine Com-
pany, 75 West Houston street, New York City; the Murdock Liquid
Food Company, Boston, Mass.; Fougera and Company, 90 Beekman
street, New York City, and the Liebig's Extract of Meat Company.
From the following manufacturers no reply was received:
Swift and Company, Chicago, 111.; G. H. Hammond Company,
Chicago, 111.; Cibils Company, New York City; Royalty Specialty
Company, New York City; The Bovox Company, Boston, Mass. ; The
London Essence Company (W. B. Hurd and Company), 18 Cedar
street, New York City; Ph. Rudisch (Cheppe and Schur, agents),
Third avenue and Sixtieth street, New York; American Malted Meat
Company, South Milwaukee, Wis.

The Arlington Chemical Company.

No. 16041.

The analysis submitted by you evidently refers to the preparation, Beef Peptonoids
Powder, formerly manufactured by us, but which was superseded June 1, 1906, by an
entirely different form, under the name of Dry Peptonoids (Soluble). This was done
after several years' experimentation demonstrated that we could increase the nutrient
value, improve the taste, and render the powder entirely soluble. The old form, Beef
Peptonoids Powder, has been taken off the market and all stock in hands of the trade
taken up.

Therefore we believe that the publication of an analysis of this obsolete preparation
can be of no possible interest to anyone, and that the composition of the form now in
use and on the market should be determined and published by you. * * *

We believe, in view of the facts as given herewith, that in justice to us, and in order
that the object of the Bureau of Chemistry be accomplished, an analysis of the Dry
Peptonoids (Soluble) should be made by you and published in accordance with the
provisions of the act of Congress cited in your letter.

[In accordance with the request of The Arlington Chemical Com-
pany, the following analysis of the "Dry Peptonoids (Soluble)," as
made by their chemist, December 15, 1906, is given in this connection:]

Per cent.

Moisture 5.6

Nitrogenous compounds (N x G.25) 39. 5

Total carbohydrates, after inversion 46. 7

Ether extract (fats and lipoids) 0.3

Mineral constituents (ash) 5.8

Insoluble material 1.0

Comment by authors. — The writer was informed that as the entire
report represented the samples on the market in the winter of 1905-6
it would not be just to other manufacturers to bring the work up to
date in one case alone.

Armour and Company.

Nos. 15869, 15870, 15910, 15904, and 15907.

The results are very different from what we should expect, and from results which
we have obtained in our experience with these products.

The most striking feature is the low results you report on kreatin and kreatinin. As
a matter of fact we find that it makes a great difference which method is used in deter-

10 MEAT EXTRACTS.

mining total kreatinin. The method we use in this laboratory is the modification of
Folin's method as suggested by Grindley and Woods. From our experience we pre-
sume that the method you use is the same as that outlined in the proposed methods for
the cooperative work on the sample of beef extract sent out June 3, 1907. Our results
on this cooperative work, as well as our analyses of several other samples, give materially
lower figures for total kreatinin « by the method furnished us by Mr. Cook in his letter
of June 3 than by the method of Grindley and Woods.

We also note that the percentage of proteid b as determined in fluid extract of beef is
not proportional to the proteid as determined in solid extract. Inasmuch as one is
made from the other by mere solution in water, we are unable to find an explanation
for this difference, assuming that both were determined by the same method. We
note also that the total nitrogen in these two preparations is not proportional.

Among other features that we note we shall mention only the unusually high moisture
in Soluble Beef. It is considerably higher than our records.

Comment by authors. — The fact that some of .the results vary with
the method used has already been discussed, and this is especially the
case with kreatinin. As the same method was applied to all the sam-
ples reported, no injustice is done.

The percentage of moisture and total nitrogen in the solid and fluid
extract are proportional, but the percentage of total proteids in the
fluid extract is lower than in the solid extract. This, however, is
compensated for by a correspondingly higher percentage of meat
bases. This may be due to the failure of the tannin-salt reagent to
precipitate all of the proteid, and consequently a higher meat base
result is obtained.

Bovrii, Limited.

No. 15909.

We have to thank you for your favor of September 21, but we can not help thinking
thai there has been a misunderstanding somehow, for our standard for moisture and
ashc in Johnston's Fluid Beef is 32 per cent and 19 per cent, respectively.

A careful analysis of the last three batches made has given —

Moisture. Ash.

No. 1 33.09 19.34

2 31.22 18.80

3 32. 61 19. 20

We are under the impression that the sample you have analyzed is a cordial and
not the original Johnston's Fluid Beef. The latter is a paste standardized as above,
whereas the cordial is a liquid prepared with a higher percentage of moisture for con-
venient use in saloons, etc.

Comment by authors. — The product reported under No. 15909 was
labeled as "Johnson's Fluid Beef." Owing to the statement of the
manufacturer, a new sample was obtained on the market and the
moisture and ash determined again. This sample contained 38.62
per cent of water and 13.18 per cent of ash.

a See Tables II, IV, and IX.
b See Tables III, V, and X.
c See Table IX, page 26.

COMMENT BY MANUFACTURERS. 11

The Ctjdahy Packing Company.

Nos. 15867 and 15979.

For your information we wish to say that the Extract of Beef we are now putting on
the market is, in our estimation, a superior article to the preparation we were selling at
that time, and we are having an analysis made of our present manufacture and will
submit the figures to you as soon as completed.

Libby, McNeill and Libby.
No. 16048.

In reply to your favor of September 21, in reference to your analysis of our Premier
Brand Extract of Beef, will state that we have carefully examined our analyses for an
extended period and find that our determinations are not in accordance with your
analysis. You, of course, recognize that in the making of this product there is sure to
be considerable variation and we feel sure your Department does not expect each
batch to be an exact duplicate of every other one. * * *

We have had our chemist analyze samples from our present stock and submit the
following, which are the average of his determinations of the various samples analyzed —

Per cent.

Total nitrogen 7. 66

Ether extract 53

Lactic acid ....._. 7. 97

Ammonia 56

Undetermined 12. 34

Per cent.

Moisture 19. 54

Ash.... 27.80

Sodium chlorid 11. 32

Proteid ! 13.12

Meat bases 18. 12

Total kreatinin 5. 40

Comment by authors. — An unsuccessful attempt was made to secure
another sample of this product.

H. K. Mulpord Company.

No. 16044.

A comparison of the results with analyses on record in our laboratory agree quite
well in the main. * * * Some eighteen months ago we revised our label and litera-
ture on Predigested Beef in an effort to have our statements conservative and in accord-
ance with the standards established through assay of the finished product.

Parke, Davis and Company.
Nos. 15970 and 15991.

Acknowledging the receipt of your two reports upon Mosquera Beef Jelly (Extract
of Beef) and Mosquera Fluid Beef Jelly, we beg to say that we have no particular criti-
cism to offer to the results as outlined any further than to say that they agree in a gen-
eral way with the data which we have obtained and which have been obtained by
others in the analysis of these two products. * * * You of course realize that the
results obtained from the analysis of different samples of beef extract will vary, and
the same is equally true of the results obtained by different operators. Furthermore,
the results as expressed vary according to the method of assay employed, particularly
as regards the interpretation placed upon the content of nitrogen.

* * * We presume to suggest that the estimation of a total acidity of beef extracts
as lactic acid will be regarded by analytical chemists as somewhat of an innovation.
This is certainly calculated to work some injustice in the case of our beef extracts,
inasmuch as fruit acids are incorporated through the use of the pineapple juice em-
ployed in the process of manufacture.

12 MEAT EXTRACTS.

May we ask, therefore, that you will incorporate in your final report some note to
the effect that the total acids of the extract are calculated as lactic acid, and further-
more a statement that " Juice of partially ripened pineapples is employed as a digestant
in the manufacture of Mosquera Beef Extract.0 The high percentage of acidity is
probably therefore accounted for by the acidity of the pineapple juice.

Comment by authors. — The points raised as to method of stating
acidity are elucidated by table headings and context.

James P. Smith and Company.
No. 15978.

We have not imported the article labeled "Maggi Bouillon" since November, 1906,
as under the advice of your Department we changed the label so that it read " Maggi
Essence."

It is not a food product in the general acceptation of the term, but an essence which
is added in very small quantities as an improver to insipid soups, weak bouillon, etc.

John Wyeth and Brother.

No. 15965.

In comparing the results of your analysis with the figures obtained in our own labo-
ratories, as well as with the analysis made some years since by Dr. Fresenius, of Wies-
baden, we are glad to say that in a general way the three analyses agree, particularly
in view of the fact that doubtless the methods used in the different determinations
have varied to some extent. The only appreciable difference we notice between your
analysis and that of Fresenius is in the percentage of meat bases, & which in his analysis
is reported as 14.33 per cent as against your 5.99 per cent, but we find that this is due
to a difference in the factor employed, that used by Fresenius being 6.25, while you
have used the now generally accepted factor 3.12 in calculating the meat bases. We
have ourselves determined the meat bases as amounting to 8.26 per cent, by precipi-
tating the total proteids with bromin, deducting the percentage of nitrogen which
they contain from the total nitrogen and multiplying the difference by the factor 3.12.

MEAT EXTRACTS.

Tentative Standards.

The following standards were issued for criticism by the Committee
on Food Standards of the Association of Official Agricultural Chemists,
on November 19, 1906, but have never been officially promulgated by
the Department.

SOLID MEAT EXTRACT. c

1. Meat extract is the product obtained by extracting meat with boiling water and
concentrating the liquid portion by evaporation after the removal of fat, and contains
not less than seventy-five (75) per cent of total solids, of which not over twenty-seven

a Acidity of sample No. 15976 given in Table IX; No. 15991 in Table X.

& See Table X, page 27.

c Subsequent action by the Joint Committee on Food Standards, representing the
Association of Official Agricultural Chemists and the Association of State and National
Food and Dairy Departments has modified the standard to read "not less than 8
per cent is nitrogen," inserted the word "Fresh" before the word "Meat" in the
first line, and added the words "and kreatinin " in the last line. These changes
have not been officially promulgated.

METHODS OF PREPARATION. 13

(27) per cent is ash and not over twelve (12) per cent is sodium chlorid (calculated
from the total chlorin present), not over six-tenths (0.6) per cent is fat, and not less
than seven (7) per cent is nitrogen. The nitrogenous compounds contain not less
than forty (40) per cent of meat bases and not less than ten (10) per cent of kreatin.

FLUID MEAT EXTRACT.

2. Fluid meat extract is identical with meat extract except that it is concentrated
to a lower degree and contains not more than seventy-five (75) and not less than
fifty (50) per cent of total solids.

In connection with these tentative standards, the following requi-
sites for a meat extract given by Liebiga are of interest:

1. A good extract should contain no albumin and no fat (the latter not above 1.5
per cent^.

2. The water content should not exceed 21 per cent.

3. About 60 per cent should be soluble in 80 per cent alcohol.

4. The nitrogen content should run from 8.5 to 9.5 per cent.

5. The ash should vary from 15 to 25 per cent, which, besides a little sodium chlorid,
consists principally of phosphates.

Methods op Preparation.

Up to a few years ago the soup liquor obtained from meat which
was parboiled in the process of preparing canned meat was entirely
wasted, but this liquor is now extensively utilized in the manufacture
of extracts and preparations of meat. In preparing canned meat
pieces of meat are placed in iron baskets which are suspended in large
tanks containing cold water. Steam is admitted and the meat
heated about one-half hour (thirty to forty minutes). The liquor,
which is the source of meat extracts, is pumped into triple-effect
vacuum pans and heated at 160° F. for about four hours. Then the
solution is transferred to a single-effect finishing kettle and heated
eight hours until the water content approximates 22 per cent.

A first-grade extract of beef is prepared from beef alone and is
usually sold in jars. An extract of the trimmed bones, to which
considerable meat adheres, is also made. The trimmings include
odds and ends of meat, muscle tissue, bone, etc., and the product is a
second-grade article. In preparing this extract the bones are heated,
not boiled, for thirty to forty minutes, and the liquor evaporated to
the consistency of extract. The extract prepared from corned beef
liquor constitutes another second-grade product. This extract has
a high content of nitrates and sodium chlorid. In addition there is
an extract prepared from pork and other meats, sold under the gen-
eral term of meat extract. Mixtures of the various meat and bone
extracts are often made. A fluid meat extract is usually a 50 per
cent solution of a solid extract.

« Rottger, Lehrbuch der Nahrungsmittel-Chemie, p. 135.

14 MEAT EXTRACTS.

Assuming that beef extract contains 21.7 per cent of water, there
is obtained from 100 pounds of "soup liquor" 1.94 pounds of com-
mercial meat extract." These figures are high, as they are calcu
lated from the total solids present in soup liquor. The manufac-
turers claim that 100 pounds of "soup liquor" will yield 1 pound of
meat extract.

In speaking of the preparation of meat extracts, Charles R. Valen-
tine b states that when raw meat is finely chopped and macerated in
the same weight of cold distilled water and squeezed out, the water
dissolves from 16 to 24 per cent of the weight of the dry flesh. If the
water infusion is heated, the albumin of the flesh separates as a
flocculent precipitate when the temperature of 133° F. is reached, and
the red coloring matter of the blood, likewise albuminous, coagulates
at 158° F. The infusion, or extract of flesh, from which the coagu-
lated albumin has been strained, when evaporated at a gentle heat
becomes darker in color. When it is dried there is obtained a brown,
rather soft mass amounting to 12 or 13 per cent of the original flesh.

Valentine says it is not claimed that extract of meat is a food, but
that it contains the extractive matter and salts of a large quantity of
beef and possesses certain medicinal and dietetic properties. From
about 32 pounds of lean beef, free from fat and bone, equal to 8
pounds of dry meat and 24 pounds of water, 1 pound of true extract
of beef can be made. A good extract should always have an acid
reaction, its color should be a characteristic yellowish brown, and it
should have an agreeable meat-like odor and taste. It should be
entirely soluble in cold water, and free from albumin, fat, and gelatin.

Solid Meat Extracts.

The percentage of nitrogen with its distribution in the various
nitrogenous bodies is given in Tables II and III and throws much
light on the quality of the extract. The meat products examined
are divided into four classes, i. e., solid and fluid meat extracts,
meat juices, based on the definitions of the standards committee, and
miscellaneous preparations. Of the six solid meat extracts reported
in Table II, several fall below the definition in one or two points.
They, nevertheless, closely adhere to them in most respects, the
percentage of nitrogen present in the form of total meat bases and
kreatinin nitrogen being sufficiently high.

The figures in Table III are obtained by calculation from those in
Table II, and represent the percentages of nitrogenous bodies present
expressed both as per cent of total nitrogen and as per cent of sample.
In order to obtain the nitrogenous bodies from the corresponding
nitrogen figures the following factors were employed: For insoluble

a U. S. Dept. Agr., Bureau of Chemistry, Bui. 13, Part 10, p. 1390.
b J. Soc. Arts, 1897, 46 : 430.

ANALYSIS OF SOLID MEAT EXTRACTS. 15

and coagulable proteid, proteoses, and peptones the factor 6.25 was
used. To obtain total meat bases, total kreatinin, and the meat
bases other than kreatinin and xanthin, the factor 3.12 was employed.
The xanthin factor used was 2.71 and the ammonia factor 1.2143.

Fluid Meat Extracts.

The analysis of these preparations is given in Tables IV and V.
As was the case with the .solid meat extracts, not all of the products
included under Table IV correspond in every detail with the definition
of the standards committee for fluid meat extracts. The solids
according to the definition should run from 50 to 75 per cent. Several
extracts in Tables IV and V are below the minimum figure. The
price of some of these products is even greater than the price of meat
extracts notwithstanding the fact that the water content is much
higher.

16

MEAT EXTRACTS.

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ANALYSIS OF FLUID MEAT EXTRACTS.

17

a
S

cS
GO

5

"C
ft

.OO'CiOiO'OO

^is

S bjl

Grams.
105.7
68.6
69.7
63.5
73.7
102.2
127.4

^OJOOiOINCOCNCO

0, Hrt

.2*2

Per ct.
0.09
.23
.50
.04
.05
.06
.09

1

C3

g
1

c

2

fl O ej

Per ct.
0.11
.20
.22
.13
.20
.18
.13

Meat
bases
other
than
kreatin
and
xan-
thin.

o © ^ co co t- r~- ©

ft.

X. r-< 00

C3 r- CO

Per ct.
0.23
.26
.22
.17
.04
.09
.08

Kreatin

and
kreat-
inin.

Per ct.

0.38
.26
.35

.48
.80
.50

.26

Per ct.
1.66
1.92
1.94
2.02
2.63
1.36
.98

1 CO

Ccj
» fl

ft o

*»

*1

ft §

4->

Per ct.
0.34
.10
.10
.69
.54
.44
.31

Insol-
uble
and
coagu-
lable
pro-
teid.

»; f o « oi t^ >h oo

ft,

"3 o •
ogg,

1'rrct.
2.85
3.15
3.06
3.87
S. OS
3.18
2.41

>>

~

'3

^11

£; CO CO "I* ■» -3< CN CN

ft,

N/10
sodium

hy-

drox-

id.

V. ••JOI'ClHOUl
OcO'fO'O'OCNCM

a

fl
5

00

=

O
o

1

-
c

Inor-
ganic
phos-
phoric
acid.

4. 5 M O! CO iH 00 3
£e-i-OCNCN ON
ft,

Or-
ganic
phos-
phoric
acid.

Per ct.
0.26
.04
.45
.46
.38
.14
.18

Total
phos-
phoric
acid.

Per ct.
2. 32
3.27
3.41
3.29
2.48
. 95
.80

Chlorin
as so-
dium
chlorid
in ash.

•^h-HNNCOOOiC
UNl-t-O^CCO

£ 00 CO n t^ 00 — < o

ft,

Total
ash.

tjCO-ICO-ICSCO'O

>JNcioi.rioM

Mois-
ture.

Per ct.

57.75

58.84

57.64

49.94

55.99

61.63

68. 97

Serial No.

15064

159115

15966

15977

15979

15990

15991

r^ r^ n oj ^

fl

i

ft

■a

"3
o

"3

00

fl

fl

i

CO
CO

e

ft
k
«j

CO

cp

1

£

CO

s

O
fl
9
§>

A

s

i =3

S'fl
I

! . OiOOOOOOJ
■£- 00 CO i-1 CO O CO CO

^ CO CO t^ CO io »o io

a,

Meat

bases

other

than

kreatin,

kreat-

inin, and

xanthin.

Soo^TP-g'coCNio

sj;0'<f'^io»0'<J1cO
^CO^-fcO'^OJCN

ft,

c
§|

Per cent.
8.07
8.25
7.19
4.39
1.01
2.83
3.32

Kreatin

and
kreat-
inin.

Per cent.
13.33
8.25
11.44
12.40
20.25
15.72
10.79

c^ fl M

Per cent.
58.25
60.95
63.40
52.20
66.58
42.77
40.06

1 90

ftCD

cb a

ft o

Per cent.
24.56
14.92
25. 16
19.12
10.38
27.99
37.76

1 CO

c aj

aS

Per cent.
11.93
3.17
3.27
17.83
13.67
13.84
12.86

Insoluble

and
coagula-

ble.

Per cent.
1.40
14.60
.98
7.49
4.30
9.75
3.32

1

00

3
O

1
CD

o
u

i =3

£'5
5I

«'CO'»N3'*NCO
CJilCNCN— 'NMH

5°

ft,

Meat

bases

other

than

kreatin,

kreat-

inin, and

xanthin.

^OONNNOOOO

UCO^^'I'uicNCN
k

ft,

fl

is cu
fl 2

a-2

Per cent.
0.62
.71
.60
.46
.11
.24
.22

Kreatin

and
kreat-
inin.

Per cent.
1.19

.81
1.09
1.50
2.50
1.56

.81

Total
meat
bases.

^ooenuoivsj

S-OOCCNINO
CvlO»033o6^CO
|>

ft,

X. »

ft 0)

„s> fl
ft o

•ixvHccsao

UeoooOcaiQUJCO
J; -V CN •* ■* CN "5 iO

ft,

1 00

o £

I- oo

A O

Per ct.
2.13
.63
.63
4.31
3.38
2.75
1.94

Insoluble

and
coagula-

ble
proteid.

Per cent.
0.25
2.88

.19
1.81
1.06
1.94

.50

Total

pro-

teids.o

htotousorioco

ft, -' -1

6

"3
'C

K

*i":-;i-~c-'
co eo 5i* f- * a

Ci C5 Oi Ci O^ © Ci
•O >C »0 '-'S »o »o >o

43689— Bull. 114—08-

18 MEAT EXTRACTS.

MEAT JUICES.

Tentative Standard.

Meat juice is defined by the standards committee of the Associa-
tion of Official Agricultural Chemists as the fluid portion of muscle
fiber obtained by pressure or otherwise, and may be concentrated by
evaporation at a temperature below the coagulating point of the
soluble proteids. The solids contain not more than fifteen (15) per
cent of ash, not more than two and five-tenths (2.5) per cent of
sodium chlorid (calculated from the total chlorin present), not more
than four (4) nor less than two (2) per cent of phosphoric acid (P205),
and not less than twelve (12) per cent of nitrogen. The nitrogenous
bodies contain not less than thirty-five (35) per cent of coagulable
proteids and not more than forty (40) per cent of meat bases.

Discussion op Results.

Several of the preparations included in miscellaneous prepara-
tions (Table IX) were advertised as meat juices. During the
autumn of 1906 several samples of meat juice were prepared in the
laboratory. Large samples of round and chuck beef were made
practically fat free, cut into small pieces with a knife, and one sample
of each pressed in the cold through cotton bags in a glycerin cylinder
press. Another sample of each was heated at 60° C. in large jars
for several hours, then pressed as above described. The analyses
of these four samples and of several other samples of meat juices
prepared in various ways in the laboratory are given in Table VI.

A meat juice naturally varies according to its mode of prepara-
tion, and more juice is obtained by heating the meat to 60° C. than
by extracting in the cold. In the, case of the samples made in the
laboratory practically one-half the nitrogen is in the form of coagu-
lable proteid nitrogen. In several cases a considerably larger por-
tion is in that form.

A meat juice is characterized by a high content of coagulable pro-
teids and a low content of meat bases. Of the so-called commercial
meat juices in Table IX none shows any appreciable amount of coagu-
lable proteid. They are, therefore, not correctly designated by the
name meat juice and their nutritive value is misrepresented by
such designation. It appears impracticable to prepare a true meat
juice for market, as the temperature necessary for the preservation
of food products in hermetically sealed packages coagulates the
proteids and changes the nature of the product. The fact that
when these higher forms of nitrogenous bodies are removed the
valuable nutritive principles of the juice are lost must be recognized,
and a product so altered should not be designated as a meat juice.

ANALYSIS OF LABORATORY MEAT JUICES.

19

In muscle tissue there is found approximately 75 per cent of water.
Of the 100 parts of nitrogen in beef, 75 parts consist of proteid mat-
ter insoluble in water; 10 parts consist of water-soluble proteid, and
12.5 parts of extractives, which are also water soluble. Unfortunately
in making these analyses the total kreatinin was not determined.
As before stated, all of these juices are characterized by a large
amount of coagulable proteid, while the percentage of the other
constituents present seems to vary with the water content. The small
amount of sodium chlorid in the ash is noticeable, and the amount
of nitrogen present in the form of albumoses and peptones is small,
as would be expected in a true meat juice. It is evident from Table
VI that there is considerable water-soluble amido nitrogen present
in the juice of meats.

Table VI. — Meat juices prepared in laboratory.

Preparation of juice.

Composition of sample.

Serial
No.

Water
in juice.

Ash.

Chlorin
as so-
dium
chlorid
in ash.

Phos-
phoric

acid
(P2O5).

Ether
extract.

Acidity

as lactic

acid.

17091
17092

Round beef, cold pressed

Chuck beef, cold pressed

Per cent.
85.76
86.85
90.65
91.90
89.56

91.10

96.13

96.58

98.11

Per cent.
1.53
1.86
1.36
1.29
1.27

1.40

.46

.43

.39

Per cent.
0.12
.20
.15
.19
.16

.12

.05

.05

.05

Per cent.
0.37
.31
.36
.29
.37

.18

.14

.11

.12

Per cent.

0.27

.30

.19

.64

Per cent.

0.27

.32

17091
17092
19766

Round beef pressed at 60° C

Chuck beef pressed at 60° C

Juice from beef chuck at 60° C. . .

Juice pressed from sirloin steak

and water

.15
.20

19767

19785

Juice extracted from sirloin
steak by cold pressure

19786

Juice extracted from beef chuck
by cold pressure

19787

Juice extracted from beef chuck
by cold pressure after 6 hours
at 60°-100° C

Serial
No.

1705)1

17092
17091
17092
19766
19767

19785

19786

19787

Preparation of juice.

Round beef, cold pressed

Chuck beef, cold pressed

Round beef pressed at 60° C

Chuck beef pressed at 60° C

Juice from beef chuck at 60° C.
Juice pressed from sirloin steak

and water

Juice extracted from sirloin

steak by cold pressure

Juice extracted from beef chuck

by cold pressure

Juice extracted from beef chuck

by cold pressure after 6 hours

at60°-100°C

Composition of sample.

Total
nitro-
gen.

Per ct.
2.08
1.74
1.16
1.09
1.09

1.18

.48

.43

.24

Insolu-
ble

nitro-
gen.

Per ct.

0.16

.29

Coag-
ulable
nitro-
gen.

Per ct.
1.37
.98
.68
12 I .41

.54
.34
.34

Proteose
nitrogen.

Per ct.
0.06
.07
.04
.07
.42

.20

Trace.

Trace.

Trace.

Peptone
nitrogen

Per ct.

0.16

.11

.01

.21

.18
None.
None.

.12

Amido
nitro-
gen.

Per ct.

0.33

.29

.43

.27
.18

.26

.14

.09

Unde-
ter-
mined
matter.

Per ct.
0.47
1.03
1.90
.40
2.92

.94

.85
.59

.25

20

MEAT EXTRACTS.

Table VI. — Meat juices prepared in laboratory — Continued.

Serial
No.

Preparation of juice.

Results in terms of total nitrogen.

Insol-
uble
pro-
teid.

Coag-

ulable

pro-

teid.

Albu- Pep-
moses. tones.

Amido
bodies.

Perct.

Per ct.

2.88

7.69

4.02

6.32

3.45

.86

6.42

19.26

38.53

16.95

15.25

50.00

Nitrogenous bodies.

Insol-
uble
pro-
teid.

Coag-

ulable

pro-

teid.

Pro-
teoses.

Pep-
tones.

Per ct.

Per ct.

0.38

1.00

.44

.69

.25

.06

.44

1.31

2.63

1.25

1.13

Trace.

None.

Trace.

None,

Trace.

.75

Amido
bodies.

17091
17092
17091
17092
19766
19767

19785

19786

19787

Round beef, cold
pressed

Chuck beef, cold
pressed

Round beef pressed
at 60°C

Chuck beef pressed
at 60° C

Juice from beef
chuck at 60° C

Juice pressed from
sirloin steak and
water

Juice extracted from
sirloin steak by
cold pressure

Juice extracted from
beef chuck by cold
pressure

Juice extracted from
beef chuck by cold

Eressure after -6
oursat60°-100°C.

Per ct.

7.69
16.66

Per ct.
65.87
56.32

58.62

37.61

44.95
45. 76
70.83
79.07

0

Per ct.

15.87
16.66
37.07
24. 77
16.51

22.03

29.17

20.93

33.33

Per ct.
1.00
1.81

Per ct.

8.56
6.13

4.25

.75

2.56

3.06
3.38
2. 13
2.13

0

Per ct.
1.03
.90
1.34

.84
.56

.81

.44

.28

.28

YEAST EXTRACTS.

Manufacture and Use of Yeast Preparations.

Yeast on hydrolysis yields extractives which are similar to those
obtained from meat. For many years yeast extracts have appeared
on the market, especially in Germany, and have also been mixed with
and used to adulterate meat extracts. Such products are now manu-
factured in this country to a limited extent. The water extract or
infusion of yeast, when evaporated in the open-kettle process, darkens
and looks like an extract of meat. Caramel is sometimes added to
further deepen the color. When the process of evaporation is allowed
to go too far, a bitter taste appears, which is due to the peptones
formed, and it is claimed this may be removed by washing with water
and dilute ammonia solution. In general the preparation of an
extract of yeast is similar to that of an extract of meat. In an extract
of yeast the higher nitrogen forms are more abundant than in meat
extract. Two samples of yeast extract examined contained 5.68 and
5.67 per cent of total nitrogen. In regard to their stimulating effect
and general action on the body the two extracts (meat and yeast) are
practically identical according to Wintgen,0 and their value as a
proteid sparer depends only in part on their nitrogen content.

«Abs. Pharm. Ztg., 1905, 50:432.

DETECTION OF YEAST EXTRACTS. 21

Methods of Detection.

Searl a suggests as a method for detecting yeast products added to
meat preparations, that a solution of the extract be boiled one or two
minutes with a modified Fehling's solution. In the presence of yeast
extract a bluish-white precipitate is obtained. Arnold and Mentzel b
claim that a slight bluish-white precipitate is given even with pure
meat extracts, but by experience an analyst learns to detect by this
method the presence of about 20 per cent of yeast extract in meat prep-
arations. Mickoc suggests the determination of kreatin and xanthin
bodies as a means of determining the nature of the extract. Wintgend
states that the filtrate from the zinc sulphate precipitate obtained
in the determination of albumoses is entirely clear in the case of meat
extracts, but somewhat turbid with yeast extracts. This he finds to
be true even when the best S. & S. filter paper is employed. By this
method the authors could detect from 20 to 30 per cent of added yeast
extract.

E. Baur and H. Barschall'' have applied the colorimetric test, as out-
lined by Folin, for kreatinin to meat and yeast extracts. They find
no kreatin or kreatinin in yeast extracts and base a distinction
between the two on this test. Salkowski-^ has studied the various
carbohydrates of yeast and gives several tests for yeast gum.

The most reliable test is unquestionably the determination of
kreatin. A yeast extract -contains no kreatin and in a typical meat
extract there is found from 10 to 20 per cent of the total nitrogen in
the form of kreatin and kreatinin. The distribution of the various
xanthin bases also is different in the two kinds of extracts; in meat
extracts, according to Micko/ xanthin and hypoxanthin predominate,
while in yeast extracts adenin and guanin predominate.

Result of Tests.

A test for yeast extracts consisting in boiling the samples for one or
two minutes with an unmodified Fehling's solution was tried. Four
samples were tested with the following results:

Color of precipitate.

A. Meat extract Very deep violet color.

B. Yeast extr?ct Very deep green color.

C. 50 per cent yeast and 50 per cent meat extract Intermediate color.

D. 25 per cent yeast and 75 per cent meat extract Violet color, not as

strong as A.

This test is of value as a qualitative and a confirmatory -test for
yeast extracts in the presence of meat extracts.

aPharm. J., 1903, 7.7:516 and 704; 1904, 72:86.

&Pharm. Ztg., 1904, 49:176.

cZts. Nahr. Genussm., 1902, 5:193; 1903, 6:781.

dArch. Pharm., 1904, 242:537.

«Arb. kaisert. Gesundheitsamte, 1906, 24:562.

/Ber. d. chem. Ges., 1894, 27:499.

S'Loc. cit.

22 MEAT EXTRACTS.

The method of Searl for the detection of yeast extract by the use of
a modified Fehling's solution was also tested. The method is as
follows :

Prepare a modified Fehling's solution by dissolving 200 grains of copper sulphate
and 250 grains of neutral tartrate of sodium- in 4 ounces of water. Add to this 250
grains of sodium hydroxid dissolved in 4 ounces of water. Dissolve 10 grains of the
sample to be examined in 1.5 ounces of water, add to this one-half volume of the above
solution and boil for one or two minutes. With genuine meat extract no precipitate
is given. When yeast extract is present a curdy, bluish-white precipitate is formed.

This method was tested on a sample of meat extract, a yeast ex-
tract, a 50 per cent solution of yeast and meat extract, and a solution
containing 20 per cent of yeast and 80 per cent of meat extract. In
the case of the meat extract a very fine precipitate was obtained.
In the three cases where yeast extract was present a flocky, bluish-
white precipitate was formed. It is evident from these results that
the presence of 20 per cent of yeast extract in meat mixtures may
be detected by this method.

Searl also gives a modification to be applied when doubtful results
are obtained by the original method. In such cases 3 to 6 grams (50
to 100 grains) of the sample are dissolved in from 4 to 8 cc (1 to 2
drams) of water. Alcohol is added to precipitate the proteid matter,
the solution is thoroughly shaken, and filtered. The residue is dis-
solved in 45 cc (1.5 ounces) of water, filtered if necessary, and the
usual method applied.

This modification was tried on 10 and 20 per cent mixtures of yeast
extract, but the results obtained were not satisfactory, and it is
doubtful if less than 20 per cent of yeast extract can be detected in
the presence of meat extract by this method.

Another test is described by Wintgen,0 who claims that the zinc
sulphate filtrate in the case of meat extracts is clear, but with yeast
extracts it is turbid. This was found to be the case, as the following
results show:

Zinc sulphate filtrate.

A. Meat extract Clear.

B. Yeast extract Cloudy.

C. 50 per cent yeast and 50 per cent meat extract ( "loudy.

D. 25 per cent yeast and 75 per cent meat extract Cloudy.

The solutions of these extracts, or mixtures, were saturated with
chemically pure zinc sulphate after adding two drops of strong sul-
phuric acid. The solutions stood over night and the nitrates were
examined in the morning. The only clear filtrate obtained was that
from meat extract alone.

The most important test for determining the nature of an extract,
whether meat or yeast, is the determination of kreatin and kreatinin.
This test, which has been used in the Bureau of Chemistry for two or

« Arch. Pharm., 1904, 242:537.

DETERMINATION OF KREATININ.

23

three years and found to be of great value, was perhaps first applied
by Micko.a As before stated, yeast extracts contain no kreatin or
kreatinin, while in meat extracts these two bodies are present in con-
siderable amounts.

Some experiments on meat extract, yeast extract, and mixtures
of the two were tried with satisfactory results, using the Folin6 colori-
metric method. In determining the kreatinin by this method in the
presence of yeast extract, slightly higher results are obtained than
when yeast extract is not present. When the kreatin and kreatinin
are determined together (after dehydrolysis) in a sample of meat
extract the presence of yeast extract does not seem to affect the
results. In the case of the yeast extract no kreatin or kreatinin was
found, as is shown in Tables VII and VIII.

Table VII.- -Kreatinin in meat and yeast extracts.

No.

Description of sample.

Weight

of
sample.

Krea
Weight.

tin in.
Per cent.

Kreatinin

calculated

to meat

extract

used.

Increase of
kreatinin
due to pres-
ence of
yeast ex-
tract.

1

Grams,
j 0.2660
\ .2663

Mg.

8.804
8.804

3.39
3.31

Per cent.
3.39
3.31

Per cent.
0

3.35

0

1.87

1.87

135

0

3.75

3.75

0

.4800
f .4154
\ .3756

0

7.788

7.013

0

3

Mixture— 50 per cent meat and 50 per cent

0.40

1.87

3.19
2.62

3.75

4.25
3.49

4

Mixture— 75 per cent meat and 25 per cent

f .2638
\ .3030

8.437
7.941

.52

Average

2.91

3.87

Table VIII. — Total kreatinin {including kreatin converted to kreatinin) in meat and

yeast ertracts.

Description of sample.

Weight

of
sample.

Kreatinin.

Kreati-
nin cal-
culated
to meat
extract
used.

Increase
of kreat-
inin
due to
presence
of yeast
extract.

Kreatin
calculated
as kreat-
inin (by
difference) .

No.

Weight

Per

cent.

1

Grams.
10. 2210
\ .2144

Mg.
11. 571
9.870

5.24
4.60

Per cent.
5.24
4.60

Per cent.
0

Per cent.
\ 4.92-3.35

Average

/ — 1. 57

4. 92 4. 92

?

.5250
i . 4378
I .4020

0

11. 571
9.691

0

2.64
2.41

0

5.29

4.82

0

0

3

Mixture— 50 per cent meat and 50 per cent

1 5.05-3.75
J =1. 30

0.13

2.53

438
3.19

5.05

5.85
4.25

4

Mixture— 75 per cent meat and 25 per cent

/ .3554
\ .3255

15. 577
10.385

1 5.05-3.87
j* =1. 18

.13

Average

3.79

5.05

a Loe. cit.

bZts. physiol. Chem., 1904, ^:223.

24 MEAT EXTRACTS.

MISCELLANEOUS PREPARATIONS.

Classification.

In Tables IX and X are reported all commercial samples examined
which do not fall under either Table II or Table IV. No samples
were found to comply with the definition for meat juice, nor were
any peptones of American manufacture examined. The well-known
German albumose and peptone powders, somatose and Witte's pep-
tone, seem to answer the definition of peptones. A class of products
consisting largely of albumoses and peptones under the general
name of "atmid" or steam products is on the market. Another
class of albumose and peptone preparations is prepared by chemic-
ally treating lean meat with acid and pepsin, by means of which all
the fibrin, albumin, and gelatin are rendered soluble after being
digested in water at a temperature of 100° F.

In this connection attention may be called to the crab extracts
which have recently appeared in the German market. Ackermann
and Kutscher" describe and present the analysis of an extract pre-
pared from the flesh of crustaceans. This product has appeared on the
market in Germany under the names " Krebsextract," "Krebsbut-
ter," and "Krabbenextract." Extracts of this class do not repay
the outlay necessary for their preparation. The usual method em-
ployed in manufacturing a meat extract was used. The nitrogen
bodies were separated by the Steudel-Kutscher treatment with
tannin, baryta, and lead. No kreatin or kreatinin was found, but
an abundance of leucin, tyrosin, arginin, and lysin. Several of the
constituents of this extract have been isolated and identified. Other
extracts are prepared from fish, shrimps, clams, anchovies, etc., but
are not of any great commercial importance.

The various extracts, juices, and powders included in Tables IX
and X under "Miscellaneous preparations" are grouped according
to the following classification: Class I, includes extracts with high
total kreatinin (approaching 10 per cent) and a total meat base con-
tent of 40 per cent. The proteose and peptone nitrogen should run
from 30 to 50 per cent. Products in Class II have a proteose and
peptone nitrogen content above 50 per cent. They are low in both
kreatinin and meat bases. Class III includes preparations that
are low in proteose and peptone nitrogen and in kreatinin, but high
in meat bases. Class IV includes extracts that are high in insoluble
and coagulable proteid. The last four extracts are included in the
fourth class. Extract marked No. 15910 resembles those of Class I
and the extract marked No. 16037 those of Class II, but in both
cases the insoluble and coagulable proteid figures are high. Sev_
eral meat powders are included in Table VII. The number of such

aZte. Nahr. Genussm., 1907, 13. 180, 610, 613.

MISCELLANEOUS PREPARATIONS. 25

products is far less numerous than the solid and fluid extracts.
These products consist largely, if not entirely, of albumoses and
peptones in addition to some insoluble proteid matter. The amount
of insoluble and coagulable proteids is relatively small in most of
the samples examined and the balance of the nitrogen is distributed
between the proteoses, peptones, and meat bases. The relative
amount of these nitrogenous bodies present depends on the method
of manufacture and extent of the hydration to which they are sub-
jected. The net weights, as well as the retail prices of the extracts
purchased, are interesting and are given in Tables II, IV and IX.

Discussion of Results.

In several of these preparations but a small amount of meat extrac-
tives or bases is found. The amount of kreatin and kreatinin is
negative in several cases, showing that the products in question
were not made by the evaporation of an infusion of meat. The
total nitrogen is extremely low in a number of instances, falling to
0.42 per cent in sample 16044. The stimulating value of the amido
acids and the nutritive value of the higher forms of nitrogen must
be exceedingly small in these cases. This same sample (16044)
contains 91.69 per cent of water and retails for $1 per bottle of 477
grams. Another sample, 15989, retailing for 60 cents a bottle of
179 grams, is evidently largely an artificial product and on applying
the method for the determination of organic phosphorus the sample
did not appear to resemble a beef juice or extract. This sample
contains but 2.36 percent total nitrogen, of which only 3.81 percent
is in the form of meat bases; kreatinin is lacking, the insoluble resi-
due is relatively large, and alcohol is present.

26

MEAT EXTRACTS.

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NITROGENOUS CONSTITUENTS.

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28 MEAT EXTRACTS.

METHODS OF ANALYSIS AND THEIR DISCUSSION.

One of the great obstacles in the way of a thorough and careful
study of proteids is the unsatisfactory condition of the analytical
methods. Many of the variations in results which have appeared
are undoubtedly due to faulty methods. Another serious source of
error in this line of work lies in the fact that different methods are
used by different analysts and the results are not comparable. For
instance, copper oxid, phosphotungstic acid, tannic acid and salt, and
other reagents, are used by various workers to precipitate the higher
amido bodies and separate them from the simpler amido bodies.
That the precipitating power of these reagents is not the same is well
known. For determining acid and alkali albumins, insoluble proteid,
and coagulable proteid, the methods give only approximate results,
those for the determination of several of the individual bodies, such
as kreatin, kreatinin, and ammonia, being in a much more satis-
factory condition.

PREPARATION OF SAMPLE.

In the case of liquid and semiliquid preparations the bottle should
be thoroughly shaken and great care taken to see that the solution is
complete. Pasty and solid extracts or powders should be removed
from the container and thoroughly mixed before sampling. A very
convenient method is to dissolve a weighed sample in a measured
quantity of water and run this out of a burette as needed. This
solution should be kept cold and the determinations started without
delay.

MOISTURE.

Moisture was determined in the various preparations examined by
drying the sample over night in a ^ater-jacketed drying oven. In
the case of solid meat extracts approximately 3 grams of the sample
were used, for fluid extracts, 10 to 12 grams, and for meat powders, 2
grams.

ASH.

The ash content of the commercial samples is seen to be surprisingly
high in many cases. (See Tables II, IV, and IX.) This is due to the
fact that sodium chlorid is present in meat extracts in varying and
often excessive quantities. Especial attention is called to the large
percentage of sodium chlorid present in several of the samples exam-
ined. The figures reported in the tables are obtained by calculating
the total chlorin to sodium chlorid.

The ash was determined by the official method a and the sodium
chlorid in the ash by the following procedure:

Dissolve the ash sample with nitric acid and make up to volume in a 200-cc flask.
Use 20 per cent, or any convenient aliquot, for titration with sulpho-cyanid according
to the Vol hard method.

«U. S. Dept. Agr., Bureau of Chemistry, Bui. 107, p. 38.

METHODS OF ANALYSIS.

29

A small amount of sodium chlorid is present in meat, and as much
as 12 per cent is permitted by the tentative standard for meat extract,
but the presence of 25 to 30 per cent is excessive and should be
regarded as an adulteration.

From 0.8 to 1.8 per cent of meat is mineral matter, and calculated
to water-free substance this amounts to from 2.3 to 7.5 per cent. The
average composition of the ash of meat, according to Konig,a is as
follows :

Per cent.

Potassium 37. 04

Sodium 10. 14

Calcium 2. 42

Magnesium 3. 23

Oxid of iron 0. 44

Per cent.

Phosphoric acid 41. 20

Sulphuric acid 0. 98

Chlorin 4.66

Silica 0. 69

Jolly 6 gives some very interesting figures showing the various com-
binations of phosphoric acid found in the muscles and tendons of
calves and oxen, and the metabolism of the various mineral salts
is fully discussed by Albu and Neuberg.c The analyses of the ash of
several samples of meat juice prepared in the laboratory are given in
Table XL

Table XI. — Analyses of ash of meat juices.

Substance.

Chlorin

as
sodium
chlorid.

Composition of salt-free ash.

Serial
No.

Insol-
uble
matter.

Cal-
cium
oxid.

Mag-
nesium
oxid.

Potas-
sium
oxid.

Resid-
ual so-
dium
oxid.

Sul-
phur

tri-
oxid.

Phos-
phoric
acid
(P2O5).

197ti6
19767

Juice from beef chuck at 60°C

Juice pressed from sirloin

steak

Per ct.
12.37

8.56

10.20

12.15

13.43

Perct.
0.45

0. 56

1.02

1.06

1.69

Perct.
0.89

0.96

Trace.

Trace.

Trace.

Per ct.
0.10

Trace.

Trace.

0.49

0.37

Perct.

47.85

45.67
49.77
47.30

51.58

Per ct.
5.91

2.71

4.64

8.03

9.46

Perct.
3.37

1.56

0.66

0.74

1.91

Per ct.
33.22

37. 12

19785
19786
19787

Juice extracted from sirloin
stoak by cold pressure

Juice extracted from beef
chuck by cold pressure

Juice extracted from beef
chuck after 6 hours at 60°
to 100° C

33.74
29.56

34.20

The most striking point in the analysis of the ash of meat extracts
is the large amount of potash salts present, practically one-half of
the salt-free (XaCl-free) ash being composed of potassium oxid.
The amount of phosphoric acidd is also high, amounting to fully
one-third of the salt-free ash. The percentage of phosphoric acid
given in the table may be low, as part of the organic phosphoric acid
is volatile especially if the ash be heated to a very high temperature.
The other constituents of the ash of meat juice are oxid of iron,

« Chemische Zusammensetzung der menschlichen Nahrungs- und Genussmittel.
1889. 3rd cd., 1: 236.

&Compt. rend., 1879, 892K&.

c Mineral Stoffwechsel, Berlin, 1906.

dThe provisional volumetric method was used — U. S. Dept. Agr., Bureau of Chem-
istry, Bui. 107, p. 16.

30

MEAT EXTRACTS.

calcium, magnesium, and sodium. Phosphates and sulphates of cal-
cium and potassium, organic sulphur, and a small amount of insoluble
matter, principally silica, are also present.

In Table XII figures are given showing the composition of the ash
of various meat extracts and miscellaneous preparations. As the
percentage of sodium chlorid shown in Table XII is much greater than
that present in the natural meat juice, the figures for the salt-free
ash are correspondingly lower. The amount of insoluble matter is
surprisingly high in several cases and it appears that some insoluble
substance must have been added. For comparison the following
results are quoted from K6nig,a showing the average composition of
the ash of meat extracts:

Per cent.

Potassium 42. 26

Sodium .' 12. 74

Calcium, 0. 62

Magnesium 3.15

Chad of iron 0. 28

Results of the analysis of the ash of meat peptones are also given.
Konig states t hat the salts, especially the potash salts present in the
ash of meat extracts, are valuable on account of their action on the
nervous system.

Table XII. — Analyses of the ash of meat extracts and miscellaneous preparations.

Per cent.

Phosphoric acid 30. 59

Sulphuric acid 2. 03

Silica : 0. SI

Chlorin 9. 63

Serial No.

18152
18159
18161
18434
18435
18563
18584
18623
18624
19398
19399
19461
19707
19818
18460
18633
18636
19458
19460
19465
19467
18629
18635
18637
19817
18877

Chlo-
rin as
sodium
chlo-
rid.

Per

cent.
39.78
40.85
63.47
41.39
82.13
34.22
53.23
75.27
33.64
32.65
Ml 86
37. 61
12.78
12.24
12.21
42.34
22.93
30.88
12.21
49.97
57.17
47.33
54.80
53.98
48.02
39.48

Composition of salt-free ash.

Insol-
uble
mat-
ter.

Per

cent.

0.42

.22

.27

4.66

.67

1.43

1.62

0

.74

8.02

9.05

2.74

9.97

3.01

29.38

5.38

1.70

.61

29.38

5.74

1.35

11.35

17.28

.65

3.46

14.11

Ferric
oxid.

Per

cent.

(»)

Cal-

Mag-

Potas-

Resid-

Sul-
phur
tri-

oxid.

Per

cium
oxid.

nesium
oxid.

sium
oxid.

dium
oxid.

Per

Per

Per

I'<r

cent.

cent.

cent.

cent.

cent.

0.27

0.35

.53.44

7.31

5.50

Trace.

Trace.

40.81

6.20

11.19

1.42

.47

50.31

6.52

8.13

Trace.

.90

46. 92

13.97

4.69

1.62

Trace.

27.59

21.94

Trace.

.17

45.53

8.47

2.19

.26

.41

64.70

6.37

2. 46

Trace.

Trace.

40.36

Trace.

Trace.

50.51

10.02

3.47

.46

.56

61. 36

4.08

2.55

Trace.

Trace.

49.07

5.27

5.44

3.72

Trace.

39.01

13.24

15.18

Trace.

Trace.

42.85

10.40

2.59

Trace.

Trace.

41.21

9.64

2.96

.32

Trace.

27.59

6.99

1.81

7.80

16.82

3.17

3.40

16.30

Trace.

.18

43.88

4.76

3.48

9.33

.95

30.22

6.03

5.30

.32

Trace.

27.59

6.99

1.81

.64

.54

45.75

4.94

3.70

Trace.

Trace.

47.02

5.23

10.60

.59

Trace.

46.82

18.36

2.56

Trace.

Trace.

39.00

9.09

4.51

Trace.

Trace.

49.63

18.99

2.33

Trace.

Trace.

32. 42

9.22

6.25

Trace.

.17

34.96

7.72

3.27

Phos-
phoric
acid
(Ps05)

Per
cent.
23. 26
25. 56
24.50
25.25
23.84
23.99
30.08
29.40
22.30
24.29
27.09
26.05
22.70
20.75
26.37
.69
28.31
37.53
3ft 37
32. 18
29.65
27.51
23.98
36. 05
24.53
16. 86

Alkalin-
ity (N/10
hydro-
chloric
acid).

cc per 100
grams.
79.71
60.86
85.96
26.10
49. 80

70. 13
63.49
CO. 47

68. 70

55.04
43.06

65.91
107.64
43.06

75.66
79.10
33.31

a Loc. cit.

6 Present in small amount.

c Present.

METHODS OF ANALYSIS. 31

SEPARATION OF ORGANIC AND INORGANIC PHOSPHORUS.

The 10:1 ratio of total phosphoric acid to organic phosphoric acid
suggested by Siegfried and Singewald a is not constant. This method
should be further investigated before applying it to all extracts and
food products in general. The high inorganic phosphoric acid con-
tent in some cases might be explained by the fact that phosphates
may have been added, but we should hardly expect this in the case
of organic phosphorus.

The method of Siegfried and Singewald for the separation of the
organic from the inorganic phosphorus was applied to meat extracts
in the following manner:

Dissolve an amount of the original sample corresponding to 10
grams of the water-free material in water in a 300 cc flask. Add 50 cc
of barium chlorid (10 per cent solution) and 10 cc of ammonia (10
per cent solution) . Make the solution up to the mark and thoroughly
shake. Allow to stand and employ an aliquot of 250 cc of the filtrate
for the estimation of phosphorus by the peroxid method to obtain
the amount of phosphorus present in organic form. This figure sub-
tracted from the amount of total phosphorus gives the amount of
phosphorus in the inorganic form. The accuracy of the method is
questionable as the filtrate in the majority of cases was cloudy, and
sometimes the slow filtration renders the method extremely tedious.

ACIDITY.

In the average solid or pasty extract the lactic acid content varies
from 4 to 8 per cent, and, as a rule, the extract showing the highest
phosphoric acid content likewise shows the highest acidity. This is
undoubtedly due to the fact that some of the phosphoric acid is in
the form of dihydrogen or acid phosphate, although the character of
the acidity has not been definitely determined.

The method employed for determining acidity consisted in adding
tenth-normal sodium hydroxid to a dilute solution of the meat
extract in water until a drop removed by means of a small capillary
tube and tested on a piece of litmus paper gives a neutral reaction.
The results are expressed in cubic centimeters of tenth-normal
sodium hydroxid, also as per cent of lactic acid present. It is recog-
nized that the acidity of meat extracts is due to various causes, but
lactic acid is the predominating acid, and the results for acidity are
usually expressed in the case of such products as per cent of lactic
acid. (See Tables I, III, and IX.)

<*Zts. Nahr. Genussm., 1905, 10\f>2\.

32 MEAT EXTRACTS.

NITROGENOUS BODIES.

Classes of Nitrogenous Constituents and General Methods of Separation.

It is believed that the proteids are made up of molecules of extreme
complexity — hundreds of atoms of carbon, hydrogen, oxygen, and
nitrogen — but the arrangement of these atoms and their number
have not been definitely determined. Various proteid substances are
spoken of, for example, albumins and peptones, as pure chemical
substances, but it is impossible at present to prepare two specimens
of egg albumin exactly alike, and in the case of peptones even more
difficulty is encountered. Because certain nitrogenous bodies give
color reactions that are alike and exhibit a few points in common,
they are grouped together under a definite term. It is not surpris-
ing, therefore, that the methods for the separation of nitrogenous
bodies are far from satisfactory in many cases.

Professor Mallet" says the following classes of the nitrogenous
constituents of food are commonly recognized as requiring separate
consideration :

1. Proteids proper (by some called albuminoids), and their closely related deriva-
tives, trie proteoses and peptones.

2. Gelatinoids or collagens, and allied substances immediately derived from them,
such as gelatin, chondrin, etc.

3. Simpler amids, amido-acids, and allied substances, such as the asparagin, glu-
tamin, etc., of vegetable materials, and the "flesh bases" (kreatin, kreatinin, etc.)
of animal origin.

4. Alkaloids, or amine-like compounds of well -determined basic character.

5. Ammonia and its salts,
fi. Nitrates.

To these, no doubt, should be added lecithin and analogous sub-
stances containing nitrogen, but closely allied to the fats.

The average nitrogen content of the pasty or solid extracts usually
varies from 6 to 9 per cent. The nitrogen in the so-called meat juices
is subject to much greater fluctuation, depending largely on the con-
tent of solids. Although a high nitrogen content is not a guarantee
of the character or mode of manufacture of an extract, an average
nitrogen content is desirable.

All nitrogen determinations were made by T. C. Trescot.

Several new determinations were applied to the analysis of meat
products. These include the separation and estimation of the meat
bases by a modification of the Schjerning tannin-salt method,6 the
determination of kreatin and kreatinin by the colorimetric method of
Folin,c the determination of xanthin bases by the method of Schitten-
helm/ the estimation of ammonia by the magnesium oxid method,"

« U. S. Dept. of Agr., Bureau of Chemistry, Bui. 54, page 7.

b J. Amer. Chem. Soc, 1906, 12:1485.

cZts. physiol. Chem., 1904, 41:223.

^U. S. Dept. Agr., Bureau of Chemistry, Bui. 90, page 129.

«U. S. Dept. Agr., Bureau of Chemistry, Bui. 107, page 9.

METHODS OF ANALYSIS. 33

the determination of total phosphorus by the peroxid method," and
the separation of the organic from the inorganic phosphorus by the
method of Siegfried and Singewald,6 described under ash. Sodium
chlorid was estimated by the Volhard method.0

The methods of the Association of Official Agricultural Chemists
were used in most cases.rf For the determination of total nitrogen,
total meat bases, xanthin bases, and insoluble and coagulable pro-
teids aliquots of one solution of the sample were used. The pep-
tones were determined by the tannin-salt method6 and the kreatinin^
by a modification of Folin's method (page 39).

Many reagents have been used to separate the meat bases from the
nitrogenous bodies of larger molecular weight. Phosphotungstic
acid has been more widely employed than any of the others, but is
known to precipitate many of the diamido acids,*7 and its power to
precipitate completely the peptones7' is not established. Mallet '
states that the use of phosphotungstic acid as a precipitant, fol-
lowed by washing the precipitate with hot water, seems to effect a
separation of all the simpler amidic substances from the proteids and
proteid-like bodies, excepting only the peptones. Mallet quotes
authority to show that the peptones are precipitated by tannic acid.
The method was tried in the present investigation, but was discarded.
Bromin has been suggested by Allen and Searle^ as a reagent for
separating the higher amido bodies from the lower amido acids, but it
has been found by Schjerning* and others to be unreliable. That
the tannin-salt reagent makes an absolute separation is not claimed,
but it seems to be the best at present available.

Insoluble and Coagulable Proteids.

In Table XIII figures are given showing the amount of nitrogen
present in the insoluble form as distinguished from that present in the
coagulable form. This separation was made on seven extracts in-
cluded in Table VII (miscellaneous preparations), which showed high
coagulable nitrogen figures. The provisional methods l of the Asso-
fl J. Amer. Chem. Soc, 1904, 2 6: 1108.

&2te. Nahr. Genussm., 1905, 10: 521.

cLiebig's Annalen, 1878, 190:1.

«*U. S. Dept. Agr., Bureau of Chemistry, Bui. 107.

e.U. S. Dept. Agr., Bureau of Chemistry, Bui. 99, p. 182.

/All kreatinin figures refer to kreatinin and kreatin estimated as kreatinin after
dehydration.

g Hammarsten, Physiological Chemistry, 1904, p. 80.

T. S. Dept. Agr., Bureau of Chemistry, Bui. 73, p. 92.

I U. S. Dept. Agr., Bureau of Chemistry, Bid. 54, p. 21.

J Analyst, 1897, ££: 258.

* Zts. anal. Chem., 1900, 59:545. TJ. S. Dept. Agr., Bureau of Chemistry, Bui. 81,
p. 104.

I U. S. Dept. Agr., Bureau of Chemistry, Bui. 107, p. 115.

43689— Bull. 114—08 3

34

MEAT EXTRACTS.

ciation of Official Agricultural Chemists for meat fiber and eoagulable
proteids in meat extracts were followed.

The amount of insoluble material in several instances is extremely
large and the name "extract" hardly applies to such products. The
amount of eoagulable proteid in sample No. 17882 is very high. Xo
insoluble material should be present in a properly prepared extract.
As noted under meat juice, however, the eoagulable proteid is the
characteristic form of nitrogen for such products. Meat extracts,
both the solid and liquid, contain some eoagulable proteid.

Table XIII. — Separation of insoluble and eoagulable nitrogen.

Nitrogen as

E xpressed in terms
of total nitrogen.

"

Serial
No.

Remarks.

Insol-

Coagu-
lable

Insol-

Coagu-

Total.

uble

uble

lable

proteid.

proteid.

proteid.

proteid.

Per cent.

Per cent.

Per cent.

Percent.

Per cent.

17879

4 57

1.16

a 141

25.38

ao9

Same brand as 15910, Table VI.

17880

8.505

a 15

.015

37.04

.17

Same brand as 15909, Table VI.

17881

2.015

.312

.619

15.48

30.72

Same brand as 16043, Table VI.

17882

2.435

.013

2.32

.53

95.28

Same brand as 15989, Table VI.

17884

a22

1.66

.02

51.55

.62

Same brand as 16037, Table VI.

17885

& 315

.202

.029

a 19

.46

Made by company manufactur
Tal>le" VI, but an entirely

ng 16041,

different

product, as stated on label.

17887

5.81

1.13

.021

19.45

.36

Same brand as 15963, Table VI.

Proteoses and Peptones.

The following tentative standard for peptones has been framed by
the standards committee:

Peptones are products prepared by the digestion of proteid material by means of
enzymes or otherwise, and contain not less than ninety (90) per cent of proteoses
and peptones.

The proteoses and peptones are nitrogenous bodies of smaller
molecular weight and greater solubility and diffusibility than the
albumins. They are prepared from the albumins by the process of
hydration. The peptones are below the proteoses in the process of
hydrolysis. The distinction between the proteoses and peptones
usually considered is that made by Kuhne,a who defined the pro-
teoses as nitrogenous bodies precipitated by ammonium sulphate,
while the peptones are not precipitated by this reagent. These two
bodies also differ in solubility and as to certain chemical reactions.

The zinc sulphate method6 was employed for the determination
of the proteoses. The peptones were precipitated together with the
proteoses by the tannin-salt reagent0 and the peptone figures ob-
tained by difference.

«ZtB. Biol., 1886. tS:42&.

&U. S. Dept. Agr.. Bureau of Chemistry. Bui. 107, p. 115.

cJJ. S. Dept. Agr., Bureau of Chemistry, Bui. 99, p. 182.

METHODS OF ANALYSIS. 35

In regard to the nutritive value of the albumoses and peptones
much uncertainty exists, but many investigators, as Munk,a Deiters, b
Zuntz,c Pollitzer,d and others, have shown that pure albumoses and
peptones can replace proteid matter of equivalent nitrogen content.

The nature of the proteoses, as precipitated by saturating a sam-
ple of Liebig's meat extract with zinc sulphate, was lately investi-
gated by Micko,c who applied the Fischer ester method to the pro-
teoses. He identified the following amido bodies by this method:
•Glycocoll, leucin, isoleucin, alanin, amido valerianic acid, prolin (race-
mic and active), asparaginic acid (racemic and dextrorotatory), glu-
taminic acid anhydrid, and phenylalanin. No xanthin or kreatin
was found in the proteose precipitate.

Gelatin,
general discussion.

The addition of gelatin to meat preparations has been practiced
in the past. By this means the manufacturer increased or main-
tained a certain nitrogen content, but supplied the nitrogen in a
form lacking in stimulating effect and probably in nutritive value.
The buyer was consequently deprived of the characteristic essen-
tials of a true meat product, although the nitrogen content was
relatively high. In many cases only a small proportion of the added
gelatin existed in the extract as such, as it was converted by a grad-
ual process of hydration into gelatoses and gelatin peptones. While
the methods for the separation of gelatin from proteid matter are
far from satisfactory, it is a much simpler process than the detec-
tion of gelatoses and gelatin peptones and their separation from the
albumoses and peptones, no satisfactory method for the separation
of these bodies being known.

Some gelatin may be formed in the preparation of a high-grade
extract of meat, although with proper precautions there should be
practically none present. When a sufficient amount of gelatin is
present it is readily detected by the setting qualities of the extract
after warming. The power of gelatinizing is only possessed by unal-
tered gelatin; its dissociation products do not have this power.

Micko-f has recently studied the gelatin cleavage products and
finds that practically the same bodies are formed on hydrolysis as in
the case of the albumoses. In both cases glycocoll predominates.
This investigator states that no gelatin is present in Liebig's extract

a Therap. Monatsh., June, 1888. Deutsche ined. Wochenschr. , 1889, No. 2.

6 Von Noorden's Beitriige zur Lehre vom Stnffwechsel, 1892, p. 47.

cAreh. gesam. Physiol., 1885, 57:313.

d Ibid., p. 301.

eZts. Nahr. Genussm., 1907, 7^:253.

/Ibid., p. 284.

36 MEAT EXTRACTS.

but the soluble forms (glutin and gelatoses) are present, being formed
by action of the lactic acid on the gelatin.

The following tentative standard has been framed by the food
standards committee:

Gelatin (edible gelatin) is the purified, dried, inodorous product of the hydrolysis, by
treatment with boiling water, of certain tissues, as skin, ligaments, and bones, from
sound animals, and contains not more than two (2) per cent of ash and not less than
fifteen (15) per cent of nitrogen.

EXPERIMENTAL WORK ON METHODS.

Experiments were made to test the following gelatin methods:

(1) the Stutzer ice- water alcohol method,0 modified by Bigelow; 6

(2) theBeckmannc formaldehyde method; (3) the trichlor-acetic-acid
method of Obermayer. d

The gelatin used in these experiments was a product of good
quality used in preparing culture media. With Millon's reagent it
gave a faint pink reaction in the cold, and upon heating a red color
developed, showing some proteid matter was present. This reaction
shows the presence of tyrosin, and as pure gelatin contains no tyrosin,
a small amount of proteid must have been present as an impurity.
The biuret test gave a faint reaction with the gelatin solution.

The solution of gelatoses and gelatin peptones used was prepared
by treating some of the gelatin with weak (3 or 4 per cent) hydro-
chloric acid for four days on the steam bath. This solution also
gave the Millon and biuret tests. Neither the gelatin nor gelatose
solutions showed signs of gelatinizing. The former was of 1.14 per
cent and the latter of 0.64 per cent strength.

The modified Stutzer method gives, in the case of pure gelatin
solutions, a rough approximation of the amount present, the results
showing that about 84 per cent are recovered. With a solution of
gelatoses and gelatin peptones, this method gives about 3.6 per cent
of the nitrogen present as gelatin nitrogen. This may be due to a
trace of gelatin in the gelatose solution. In the case of Witte's pep-
tone 19 per cent of the total nitrogen appears as gelatin nitrogen
according to the modified Stutzer method. It seems that the abso-
lute alcohol precipitates a portion of the albumoses present in Witte's
peptone. In the case of the meat extract used, 3.7 per cent of the
nitrogen is estimated as gelatin nitrogen by this method. Mixtures
of gelatin with gelatoses, Witte's peptone, and meat extract were
made in various combinations; also mixtures of the meat extract,
Witte's peptone, and gelatose without gelatin. The results for gela-

aZts. anal. Chem., 1895, 54:568.

&U. S. Dept. Agr., Bureau of Chemistry, Bui. 107, p. 116.

c Analyst, 1895, 20:44.

d Zts. anal. Chem., 1890, 29 : 114.

METHODS OF ANALYSIS. 37

tin were very irregular and inaccurate, and in all cases only a portion
of the gelatin added was recovered. It is evident that the presence
of albumoses and peptones, as well as of gelatoses and gelatin peptones,
tends to dissolve the gelatin and give low results by this method.

The Beckmann formaldehyde method," together with some com-
ments thereon, reads as follows:

A method for the estimation of gelatin in meat extracts is based upon the fact that
formaldehyde combines with it to form a nonfusible and insoluble compound —
formalin-gelatin. In order to render insoluble 1 gram of gelatin dissolved in water
about two drops of the 40 per cent solution in water of formaldehyde (formalin) are
added. The quantity required is so trifling that its weight may be neglected.

The presence of much free acid hinders the reaction, which, however, takes place
perfectly well in a slightly alkaline solution. * * * If formic or acetic acid be
present, either too little precipitate is obtained or none at all. * * * Soluble
egg-albumin and serum albumin left residues on mixing with formalin. * * *
Merck's dry peptone was found to be completely soluble in the presence of formalin,
and by this means gelatin and albumin could be easily separated from peptone. * * *

In determining whether a meat extract contains gelatin, the albumin is estimated
in an aliquot part of a watery solution by means of acid. Another portion is treated
with formalin, steamed on the water bath, and, after boiling for a short time with
water, the residue is collected in a Gooch crucible, dried at 100° C, and weighed.
After subtracting the amount of albumin previously found, this gives the gelatin.
The peptone, etc., in the filtrate can be precipitated in the usual way. The method
will be of use in milk analysis for detecting adulteration with an emulsion of gelatin
and fat.

The results obtained by this method were not satisfactory, and con-
firm the results obtained by Stutzer. All of the solutions were
filtered hot. The gelatin does not seem to form an insoluble formalin-
gelatin as described by Beckmann and the gelatin results were
extremely low-. In the case of meat extract and Witte's peptone,
some nitrogenous matter was precipitated by the formaldehyde, the
latter giving quite a large precipitate. When the gelatose solution
was used, practically no precipitate was obtained. On mixtures of
these various substances, either alone or in the presence of gelatin,
only incomplete results were obtained.

Obermayer agrees with Kaabe'' in stating that trichloracetic acid
will precipitate albumin and albumin peptones and thus affords a
separation from other peptones, such as gelatin peptones, which are
only precipitated by this reagent in concentrated solution.

The trichlor-acetic-acid method for precipitating gelatin as outlined
by Obermayer is briefly as follows :

Precipitate the solution with an excess of trichlor-acetic acid, and
wash the precipitate with dilute sulphuric or hydrochloric acid.
Thoroughly extract the precipitate with alcohol, then with ether,
dry and weigh the precipitate. According to Obermayer, the albu-

« Report of Thirteenth Assembly of Bavarian Chemists, 1894, pp. 18-20.
*>Zts. anal. Chem., 1882, 21 : 303.

38 MEAT EXTRACTS.

mins and gelatin, as well as the albumin and gelatin peptones, are
precipitated by this reagent. In an excess of the reagent the albumin
peptones are soluble, while the gelatin peptones are not.

A 10 per cent solution of trichloracetic acid was prepared and its
action tested on the following nitrogenous bodies: (1) Gelatin; (2)
a mixture of gelatoses and gelatin peptones; (3) Witte's peptone
(albumose and peptone preparation) ; (4) meat extract. The results
of the test are as follows:

In the case of the gelatin sample ten drops of the reagent gave a
slight precipitate, while the other three nitrogenous substances exam-
ined gave no precipitate. An excess of the reagent gave a heavy
white precipitate with gelatin and Witte's peptone, a smaller pre-
cipitate in the case of the meat extract (the reaction being obscured
by the dark color of the solution), while the gelatose solution showed
only a slight turbidity.

It is evident from these results that trichloracetic acid does not pre-
cipitate the gelatoses, neither when a small amount nor when an
excess of the reagent is used. The gelatoses are precipitated by the
tannin salt reagent and it is possible that a method for estimating the
gelatoses may be worked out on the basis of the trichloracetic acid

reagent.

Total Meat Bases.

The meat bases contain from 40 to 60 per cent of the nitrogen in
solid meat extracts, as is shown in Table III. In one of the poorest
extracts examined, but 3.82 per cent of the total nitrogen is present
in this form.

The meat bases are divided into two general classes, the mono- and
the di-amido acids. By the method of analysis employed, the meat
bases are found in the filtrate from the tannin-salt precipitate.
Some of the meat bases, for example, kreatin and kreatinin, and the
hexon and xanthin bases are well defined chemical bodies that have
been isolated and analyzed, but a considerable number of the nitro-
genous bodies classed as total meat bases are of unknown constitution
and are classed as undetermined nitrogenous matter.

Many new bodies have been found in meat extract in recent years.
Kutschera has recently found the following nitrogenous bodies:
Ignotin, methyl guanidin, carnomuscarin, neosin, novain, and oblitin.
Krimberg6 has demonstrated the presence of carnosin, carnatin,
and methyl guanidin in flesh. Mickoc applied Fischer's ester method
to Liebig's extract and found alanin, leucin, and glycocoll in abund-
ance. No amido valeric acid was found, and most of the amido acids
were left in a sirupy mass.

«Zts. Nahr. Genussm., 1905, JO: 528.
bZts. physiol. Chem., 1906, 48:412.
c Zts. Nahr. Genussm., 1902, 5:193.

METHODS OF ANALYSIS. 39

Intermediate between the peptones and the amido acids is a
class of substances, recently described by Fischer," called peptids,
which are divided into two classes, the dipeptids and the polypep-
tids. The importance of Fischer's work can not be overestimated,
as a beginning has thus been made in the important problem of deter-
mining the construction of the proteid molecule.

Kreatin and Kreatixin.
application op kreatinin test to meat extracts.

Kreatin and kreatinin are two amido bodies which characterize
meat and therefore they are natural and essential constituents of
meat preparations. The other meat bases are important constitu-
ents of an extract of beef, but occur in smaller amounts.

As kreatin is the principal amido body found in meat, we expect
to find it, together with kreatinin, its dehydrated form, in still larger
quantities in meat extracts. In several cases in which the extract
acted suspiciously, no kreatin was found, and grave doubts exist as to
the source of such products. True meat extracts give high kreatin
and kreatinin results, as well as high figures for meat bases. The
estimation of the kreatin and kreatinin is, therefore, a very important
determination and of great value in determining artificial and imita-
tion meat and yeast products, and in establishing the source and
purity of an extract of meat.

The determination of kreatin and kreatinin was carried out as fol-
lows : Use an aliquot of the filtrate from the insoluble and coagulable
proteid determination, the amount depending on the character of
the extract.6 The aliquot must contain sufficient total kreatinin,
after dehydration of the kreatin to kreatinin, to give a reading not
far from 8° on the scale of the Dubosc colorimeter after applying the
colorimetric method as outlined by Folin c for the estimation of krea-
tinin in the urine. Heat this aliquot with 5 cc of half-normal hydro-
chloric acid for three and a half hours on a steam bath under a reflux
condenser. Neutralize the hydrochloric acid by the addition of 5 cc
of half-normal sodium hydroxid, then add 15 cc of a saturated
picric acid solution, and 5 cc of 10 per cent sodium hydroxid.
Shake the solution and allow it to stand for five minutes; make up
to 500 cc and compare the color with a half-normal solution of potas-
sium bichromate in the Dubosc colorimeter. The half -normal
bichromate solution when the scale is set at 8° corresponds to .10 mg
of kreatinin and from this figure the amount of kreatinin in the ali-
quot is readily calculated.

« Untersuchungen iiber Aminosauren, Polypeptide unci Proteine (1899-1906), Berlin,
1906.

b Aliquot should represent approximately 0.2 gram of a first class, solid beef
extract.

e Zts. physiol. Chem., 1904, 41 :223.

40 MEAT EXTRACTS.

Definite amounts of kreatin and kreatinin were added to samples
of meat extracts and practically the entire amounts added were
recovered by this method. The color of the various extracts inter-
fered slightly with the reaction and attempts were made to remove
the color by precipitating with basic acetate of lead and phospho-
tungstic acid and by filtering through animal charcoal. In all such
cases, however, low results were obtained on testing the filtrate for
kreatinin. Consequently, in this work the kreatinin method was
applied directly to the coagulable proteid filtrate and no allowance
was made for the error due to the color. Since the method calls for
a dilution to 500 cc and but 10 to 15 cc are used for the determination,
this error is negligible. Grindley and Woods" have determined
separately the kreatin and kreatinin content of several extracts of
meat and found both present in varying amounts. It is necessary,
therefore, to determine these two bodies separately when a careful
study of the nitrogenous bodies of meat extract is made. Some later
experiments in the Bureau of Chemistry have shown that three and
one-half hours heating in a boiling water bath is necessary for the
complete conversion of kreatin into kreatinin. Benedict and Myers b
have described a rapid method for the estimation of kreatin and
kreatinin by conversion into kreatinin in an autoclave. This
method reduces the time of dehydration of the kreatin to fifteen
minutes.

APPLICATION OF KREATININ TEST TO TANNIN-SALT FILTRATE.

In view of the fact that a portion of the kreatin in a sample of
meat extract is precipitated by the tannin-salt reagent0 the total
kreatin and kreatinin in the filtrate from the tannin-salt precipi-
tate is determined, as well as the total kreatinin in the extract, before
adding the reagent. A more correct figure is accordingly obtained
for the total meat bases by adding to the total meat bases figures the
amount of total kreatinin precipitated by the tannin-salt reagent.
In applying the Folin method to the filtrate of the tannin-salt pre-
cipitate considerable difficulty was encountered. The tannin was
removed by means of baryta and the barium with sulphuric acid.
After neutralizing, the total kreatinin was determined in the usual
manner. In the estimation of the peptones, correction must like-
wise be made for the amount of kreatin and kreatinin precipitated
by the tannin-salt reagent.

Xanthin Bases.

In addition to kreatin and kreatinin, a true meat extract or meat
juice should contain small amounts of xanthin bases, including
xanthin, hypo-xanthin, guanin, and adenin. These bodies are de-

a J. Biol. Chem., 1907, 2 : 309. c J. Amer. Chem. Soc, 1906, 28 : 1485.

&Amer. J. Physiol., 1907, 18:397.

METHODS OF ANALYSIS. 41

rived from the nuclei of the cells, and, consequently, in an extract
that is prepared from fresh, unaltered beef a certain amount of these
bodies should be obtained together with the salts and other extractive
matter. The determination of the xanthin bases is, therefore, of
value in determining the origin of an alleged extract of meat.

The xanthin base figures in the tables show a variety of results,
which is explained by the fact that in the preparation of the extract
under certain conditions of heat and pressure some of these bodies
are destroyed. The following modification of Schittenhelm's method
was employed for their determination:

Use an amount of the standard solution equivalent to 5 grams of the original extract.'
Place in a large evaporating dish and add 500 cc of 1 per cent sulphuric acid. Evap-
orate to 100 cc within 4 to 5 hours. Cool and neutralize with sodium hydroxid.
Add 10 cc of 15 per cent sodium bisulphate, and 15 cc of 20 per cent copper sulphate;
allow this to stand over night, filter, and wash. The precipitate suspended in water
is treated with sodium sulphid and warmed on the steam bath. Add acetic acid to
acidify and filter hot. To the filtrate add 10 cc of 10 per cent hydrochloric acid and
evaporate to a volume of about 10 cc. Filter, make ammoniacal, and add ammo-
niacal silver nitrate of 3 per cent strength. After standing several hours the solution
is filtered and washed with distilled water until no longer alkaline. The nitrogen
in the precipitate is that of the xanthin bases.

Ammonia.

Ammonia in meat extracts is determined by the method0 of the
Association of Official Agricultural Chemists, which consists in distill-
ing the sample in the presence of magnesium oxid. In several of the
samples examined high ammonia results were obtained which might
indicate some degree of putrefaction. It is questionable, however,
whether the ammonia results obtained by the magnesium oxid
method are not too high.

Many investigators have stated that ammonia salts are present in
meat extracts. Probably the ammonia combines with acids of the
fatty series to form these salts, which are soluble in alcohol and vola-
tile with alcohol vapor. The ammonia is estimated by dissolving 10
grams of the meat extract in water, adding barium carbonate and
distilling. It has been suggested that ammonium salts, especially
ammonium sulphate, are added to meat preparations to increase the
nitrogen content, and in some of the extracts examined a relatively
high sulphur content was noted.

SUCCINIC ACID.

Weidel b first called attention to the presence of succinic acid in meat
extracts. Salkowski, c Kutscher and Steudel/ and others claimed

« IT. S. Dept. Agr., Bureau of Chemistry, Bui. 107, p. 9.
bLiebig'sAnnalen, 1871, 158:353.
cZts. klin. Med., 1890, Supplement to vol. 17, p. 77.
d Zts. physiol. Chem. , 1903, 38 : 101.

42 MEAT EXTRACTS.

that succinic acid was a putrefaction product and its presence in
meat extract showed that fresh meat had not been used in manufac-
turing the extract. Siegfried0 held that the source of the succinic
acid is a definite substance of acid character and he called this sub-
stance " Phosphorfleisch Saure" or "Muskelnucleon." Later work,
however, indicates that succinic acid is a cleavage product of fresh
meat formed by the action, at high temperature, of dextrose or other
reducing substance on amido acids, especially aspartic acid. Conse-
quently, the presence of succinic acid in a meat extract does not
mean that spoiled meat was used in its manufacture. In 1904 two
or three brands of American meat extract were tested for the pres-
ence of succinic acid by means of ether extraction and the pine sliver
test and this body was shown to be present. .

The question of the presence of succinic acid in meat extracts is
thoroughly discussed in a recent publication of the German Board of
Health.6 "

ETHER EXTRACT.

The ether extract should not be above 0.6 per cent in a sample of
meat extract, as the fat is liable to become rancid and injure the
flavor of the product. Moreover, a high fat content shows lack of
care in preparing the extract.

The provisional method employed for determining the ether ex-
tract c is conducted as follows:

Dry the sample over night in the presence of dry sand in a lead dish
at the temperature of boiling water. Then thoroughly grind and
extract the dried sample with anhydrous ether, in a continuous ex-
traction apparatus for sixteen hours. Satisfactory duplicate results
are obtainable by this method, but it is the opinion of the authors
that the sample should be digested with pepsin and acid before ex-
tracting with ether, in order to break up the proteid matter and thus
expose the fat to the action of the ether more completely.

GLYCEROL.

That glycerol has Deen added to fluid meat extracts and other
similar preparations is well known, and it was found in several of the
samples reported in this bulletin. The purpose in adding it seems
to be to give the product additional smoothness and bod}". More-
over, glycerol is of considerable value as a preservative. Glycerol
is burned in the body and thus becomes a source of energy, but it
does not act as a proteid sparer.

Various methods were tried for the determination of glycerol in
meat extracts and related products, including the method of the

a Zts. physiol. Chem., 1903, 39 : 126.

&Arb. kaiserl. Gesundheitsamte, 1906. vol. 24.

cU. S. Dept.- Agr., Bureau of Chemistry, Bui. 107, p. 114.

METHODS OF ANALYSIS. 43

Association of Official Agricultural Chemists a for the determina-
tion of glycerol in wines, and Lane's method,6 as well as numerous
extraction methods. Among the solvents used were benzol, amyl-
acetate, gasoline, carbon tetrachlorid, carbon bisulphid, and acetone.
All of these solvents extract varying amounts of meat bases, or
extractives, and give different results on the glycerol present. The
following reagents were used to precipitate the dissolved meat bases:
Lead acetate, silver nitrate, and phosphotungstic acid. The best
results were obtained by extracting with acetone, the meat bases
being precipitated first with silver nitrate, lollowed by phospho-
tungstic acid. The glycerol in the filtrate was estimated by the
Hehner c method.

Shukoff and Shestakoff d describe an acetone extraction method,
but weigh the glycerol, and it is impossible to estimate this bod}" in
the case of meat extracts by weighing on account of the salts and
extractives dissolved by the acetone and weighed as glycerol.

A method using anhydrous copper sulphate and extracting with
acetone is now under investigation.

NITRATES.

A qualitative test for nitrates was made in 28 samples of meat
extracts, meat peptones, fluid meat juices, and fluid extracts. The
samples were collected in July, 1907, and in general represent the
same brands as were used in the other studies.

The diphenylamin e test was used. The reagent was made by
dissolving 1 part of diphenylamin in 100 parts of concentrated sul-
phuric acid. The test was applied as follows:

Transfer 1.5 grams of the semisolid, or 1 cc of the liquid extracts,
to a 250 cc beaker and boil with animal charcoal for two or three
minutes. Filter the solution hot and test one drop of the filtrate
on a porcelain plate with three drops of the diphenylamin reagent.
A blue color indicates nitrates, and the depth of color shows in a
general way the amount of nitrates present.

Negative tests for nitrates were obtained in the case of 14 of the
28 samples examined. The results on the 14 samples giving posi-

o U. S. Dept. Agr., Bureau of Chemistry, Bui. 107, p. 83.

b Unpublished. The method reads as follows:

Precipitate a known weight or volume with basic lead acetate, make, up to a known
volume with alcohol, filter, take an aliquot part, add a little anhydrous lime, distil
nearly to dryness in a steam bath (keep the flask immersed), add an excess of anhy-
drous CaO, mix, moisten with alcohol to facilitate mixing if necessary, distil again
on steam bath to combine water with CaO, and extract with two-thirds alcohol and
one-third chloroform, as usual.

cj. Soc. Chem. Ind., 1889. 8:4.

*Zte. angew. Chem., 1905, 18:294.

eArch. Hyg., 1884, 2:373.

44 MEAT EXTRACTS.

tive reactions showed in 6 cases a slight trace and in 8 cases a very
strong reaction, indicating that the "liquor" from the parboiling of
corned beef was used in their preparation. (See p. 13.)

UNDETERMINED MATTER.

Under this head are included nonnitrogenous organic matter as
well as glycerol and carbohydrates. Glycerol has been considered
under a separate caption. The amount of undetermined matter
present depends on the mode of preparation of the extract; not
more than 10 per cent should be present in a meat extract. Inosite
and various amido acids, from which the nitrogen has been split off,
also constitute a portion of the undetermined matter.

Several of the samples which gave a high per cent of undetermined
matter were tested for starch, reducing sugar, and glycerol. The
following qualitative results were obtained:

Qualitative tests for starch, reducing sugar, and glycerol.

Sample.

Starch.

Sugar.

Glycerol.

15910

Present

None

Present

Present

None

None

None

None

Trace

Present

None

None

None.

159fti

15977

Present.

16041

16048

16049

Present.

The albumose and peptone products which are high in undeter-
mined matter, according to the tables, contain carbohydrates (starch
and sugars). In the case of several of the fluid meat extracts, or
juices, and in one or two solid extracts, glycerol is present.

HISTORICAL NOTE ON NUTRITIVE VALUES.
GELATIN.

It has long been known that gelatin is present in various amounts
in meat extracts. The collagen of the muscle on hydration yields
gelatin, and if the hydration be carried far enough soluble gelatin,
gelatoses, and gelatin peptones are found. Gelatin, while rich in
nitrogen, is not capable of keeping the body in nitrogenous equilib-
rium, since the nitrogen is not present in a form available to the body
as in all true proteids. This has lately been explained by Kaufl-
mann a on the ground that the gelatin molecule is lacking in the
tyrosin, cystin, and tryptophane groups and that by feeding these
amido bodies with gelatin animals are kept in nitrogenous equilibrium.

KaufTmann states that one-fifth of the proteid of a ration can be
replaced by gelatin, but when used in large proportions the body is

aPfluger's Arch., 1905, 109 :440.

NUTRITIVE VALUES. 45

not kept in equilibrium. This was demonstrated by an experiment
conducted by the author on himself, and also on dogs. Mancini*
has fed large amounts of gelatin and little proteid and claims that
gelatin has a proteid sparing action. Murlin^ has replaced two-
thirds of the proteid nitrogen by gelatin in the case of both dogs and
men reduced to a starvation level and finds the equilibrium is not
changed by this substitution. Gelatin and its cleavage products have
been studied by Chittenden and Solley e and Levene * among others.

A valuable contribution to the literature on the subject of the nutri-
tive value of gelatin by Murlin6 has recently appeared. The review
of the literature here given is in part taken from this article. The
experiments performed by this author were made on dogs and the
fasting requirement of nitrogen was used as a working basis. Murlin
states that the power of the organism to utilize gelatin as a proteid
substitute depends to some extent on the proteid condition of the
body at the beginning of the experiment, as well as upon the loss of
proteid during its progress.

In the experiments with dogs as high as 58 per cent of gelatin nitro-
gen was substituted for proteid nitrogen, the amount varying with the
diet. In the case of man, if two-thirds of the potential energy were
in the form of carbohydrates it was found to be possible to supply 63
per cent of the total nitrogen in the form of gelatin nitrogen for a
period of two days and maintain a daily retention of nitrogen of 0.71
gram.

Exact knowledge of the nutritive value of gelatin had its beginning
in the researches of Carl Voit/ published in 1872. As early as 1860
Voit and Bischoffs' had established experimentally the truth first
perceived by Donders,A that gelatin reduces the proteid requirements
of the body; but they were of the opinion at this time that it could
perform all the work of proteids and replace them entirely in the diet.
After Voit1 had shown that a part only of the nitrogenous excreta
is derived from the proteids of the body tissue, a portion coming from
the "circulating" proteids, he again investigated the extent to which
gelatin could be substituted for proteid, and reached the following
conclusions :

Gelatin exercises its sparing power on the proteids both with large and with small
quantities of proteid (meat) fed at the same time, and with small quantities in much

"Arch. d. Farmacol. sperim., 1906, 5: 309, 337.

&Proc. Soc. Exper. Biol, and Med., 1904, 2 :38.

cj. Physiol., 1891, 12 .2%.

dZts. physiol. Chem., 1904, 41:8.

«Amer. J. Physiol., 1907, ^9:287.

/Zts. Biol., 1872,5:297.

y Die Gesetze der Ernahrung des Fleischfressers, Leipzig, 1860.

h Die Nahrungsstoffe, Crefeld, 1853.

*Zts. Biol., 1869, 5:329.

46 MEAT EXTEACTS.

higher degree than either fat or carbohydrates. It can be shown that large quantities
of gelatin spare more proteid from combustion than do small quantities; that, however,
proteid is lost from the body even' if with large quantities of gelatin the greatest possible
amount of fat be given. A direct laying-on of gelatin, either in the glutin-yielding
tissues or in the proteid-forming tissues, is not possible, and it must therefore be
assumed that when gelatin is formed in the body it is at the expense of proteid. Gela-
tin, for this reason, is capable of replacing proteids of the food only in part. "

Voit made no special attempt to set the limits within which proteid
may be so replaced, but gives for a large dog these figures: 168 grams
of dry gelatin spared 84 grams of dry flesh.6

The next investigation bearing on the comparative value of gelatin
and proteid was that of Oerum,c who placed a dog on a daily diet of
meat, starch, butter, and meat extracts; he then replaced all of the
meat with enough gelatin to maintain the same nitrogen supply. He
records a considerable increase in the nitrogen of the urine in the
latter case.

Pollitzer,d in the course of some experiments undertaken to prove
that the products of proteid digestion are to be classed with the pro-
teids themselves, and not with the proteid-sparing foods merely,
compared the effects of gelatin on the nitrogen output with those of
horseflesh and its products of gastric digestion. He concludes that
peptone and hemialbumose (prepared by Kuhne's methods) have a
nutritive value which is in "sharp contrast with the considerable loss
of nitrogen which takes place after feeding an equivalent amount of
gelatin."

Ganze fed PaaFs glutin-peptone and was able to cover more than
half of the total nitrogen requirements therewith. Gerlach f also pre-
pared a "glutin-peptone," and found that it is a good "sparing agent,"
but is not of itself able to replace proteid.

Munk a in a brief series of experiments attempted to find the "upper
limit for the substitution of food proteid with gelatin," and reached
the conclusion that at least half as much proteid must be fed as is
destroyed by the animal in fasting, if nitrogen equilibrium is to be
maintained.

Kirchmann,A in a very painstaking research with proteid-free
gelatin, determined that the proteid destruction may be reduced
under the influence of gelatin alone as much as 35 per cent, and that
this maximum effect is obtained when 62 per cent of the body's
energy requirement is supplied by the gelatin.

"Zts. Biol., 1872, 5:297.
b Ibid.

cXordiskt medicinskt Arkiv, 1879, vol. 11, reviewed by Hammarsten in Maly'fl
Jahresbericht fur Thierchemie, 1879, 9: 308.
d Archiv gesam. Physiol., 1885, 37 : 301.
« Quoted by Kirchmann, Zts. Biol., 1900, 40:54.
/ Die Peptone. Hamburg and Leipzig, 1891.
9 Archiv gesam. Physiol., 1894, 58 : 309.
h Loc. cit.

NUTRITIVE VALUES. 47

Krummacher,a carrying the work begun by Kirchmann still
further, found that when the entire energy requirement of the dog
was covered by gelatin the total sparing was only 37.5 per cent of
the fasting nitrogen. Applied to a man whose energy requirement
is 2,500 calories daily Krummacher calculates that if 5 per cent of
his requirements were supplied in gelatin (i. e. about 33 grains of dried
and purified gelatin), the proteid' destruction in his body would be
reduced from 70 grams to about 56 grams, or, in other words, the 33
grams of gelatin would replace 14 grams of proteid.

Gregor6 used gelatin in feeding infants in certain cases where
excess of proteid was contraindicated, and concluded that with a diet
containing 4.8 grams of nitrogen per day (of which "nearly all" was
gelatin N), not more than half as much nitrogen was lost from the body
as in starvation.

Bratc prepared a gelatose, which he identifies by 'Chittenden's d
method as a deuterogelatose, and fed it to convalescent patients as a
substitute for a portion of the proteid in their diets.

Mancini6 studied the nitrogen balance of five convalescents from
typhoid fever, while giving " large quantities" of gelatin. He
observes a considerable retention of nitrogen, but doubts whether
proteid nitrogen can be replaced by gelatin nitrogen.

Kauffmann/ studied the replacing power of gelatin in a diet con-
taining "only as much proteid (mainly casein) as is necessary with a
sufficient supply of energy for maintenance of the body's condition."
He concludes from his experiments on dogs that not more than one-
fifth of the proteid in such a diet can be replaced by (pure) gelatin
if nitrogen equilibrium is to be maintained. With one-fourth of the
proteid nitrogen so replaced a small minus balance occurs. Kauff-
mann's paper is concerned chiefly with the attempt to bring gelatin
up to the full nutritive value of proteid by adding to it the amido-
acids which it lacks, but which casein contains.

Rona and Muller,^ in attempting to confirm Kauffmann's results
with gelatin, tyrosin, and tryptophan, found first "the smallest
quantity of proteid nitrogen with which the animal could well get
along," and then replaced one-fifth of this proteid (casein) with
gelatin nitrogen. Their observation as regards the amount which
would be replaced was quite in accord with Kauffmann's, for when
gelatin was substituted for two-fifths of the casein there was a dis-
tinct minus balance.

oZts. Biol., 1901, 42:242.

& Centralblatt fur innere Medicin, 1901, 22 : 65.

c Deutsche medicinische Wochenschrift, 1902, p. 21.

rfj. Physiol., 1891, 12:23.

eReale Accademie dei Fisiocritici di Sieni, 1905, 17:667.

/Archiv gesam. Physiol., 1905, 109:440.

9Zts. physiol. Chem., 1907, 50:263.

48 MEAT EXTRACTS.

The conclusions reached by the various investigators may be sum-
marized briefly as follows: Gelatin can replace proteid only in part
(Voit, Oerum, Pollitzer); it has, however, a high proteid-sparing
effect, whether fed alone (Kirchmann, Krummacher), or with other
foods (Voit, Oerum, I. Munk, Kauffmann, Rona and Muller) in infant
feeding (Gregor), or in convalescence (Brat, Mancini) ; this proteid-
sparing effect is exerted also by gelatin-peptones (Ganz, Gerlach)
and gelatoses (Brat).

MEAT EXTRACTS AND JUICES.

The various protein bodies and amido acids are so closely asso-
ciated that it is impossible to produce amido acids without produc-
ing albuminoses and peptones. Consequently, every commercial
meat extract must consist partly of albuminoses, peptones, etc. The
best extracts on the market to-day contain about 50 per cent of the
total nitrogen in the form of meat base nitrogen. When a meat
preparation contains only a small amount of its nitrogen in the form
of meat base nitrogen, the term " extract" seems to be no longer
applicable. And it is evident that the product represents much less
meat than an extract with 50 per cent of its nitrogen in the form of
meat base nitrogen, provided the total nitrogen in both cases is
approximately equal. Moreover, it is necessary to distinguish
between a meat extract containing large amounts of stimulating amido
acids and relatively small percentages of albumoses, peptones, and
insoluble proteid matter, and an extract (or, more properly, a meat
product) which consists largely of albumoses, peptones, and insoluble
matter and relatively small amounts of amido acids. The food value
of this last group of products is undoubtedly greater than that of the
former group, but they should not be classed as extracts because
of their different nature. The value of the amido bodies as food is
uncertain, but at least they furnish energy to the body. It appears,
therefore, that the value of meat extracts lies principally in their stim-
ulating qualities, the active principles of tea and coffee being on a
similar basis.

The question of the nutritive value and relative worth of the vari-
ous nitrogenous constituents of meat preparations is a much-dis-
cussed but unsettled problem. Beef juice prepared from fresh beef
by pressure and heating and used unchanged is an ideal product,
containing the extractives as well as a large amount of nutritive
material. As a commercial product, however, it is impracticable.
The higher forms of nitrogen, insoluble proteids, alkali and acid albu-
mins, and coagulable proteids, as well as the unchanged proteids, are
the most desirable forms for the healthy individual. The invalid
may require partly digested proteids, such as proteoses and peptones.
A large amount of nitrogen in this form should be avoided, as many

NUTRITIVE VALUES. 49

investigations have shown that diarrhoea and other disorders follow
the feeding of peptones. The stimulating properties of the amido
acids are most valuable in that they create an appetite and prepare
the system for food.

The scope of this report will not permit of the exhaustive treat-
ment of this' subject, but brief mention is made of the following con-
tributions as indicative of the tendency of the results obtained :

Biirgi a states that meat extracts are not foods, and that all mate-
rial taken in this form is quickly eliminated. Only 4.57 per cent of
the nitrogen, 14.85 per cent of the carbon, and 17.55 per cent of the
energy content is retained. According to Rubner6 meat extracts,
after they have served their purpose of stimulating digestion, are
eliminated from the body as rapidly as possible. W. H. Thompson0
has fed arginin to dogs and found from 37.6 to 77 per cent in the
urine; on injecting arginin 82 per cent appeared in the urine. A
part of the arginin nitrogen appeared in the urine as ammonia. Voit d
claims that the value of meat extracts lies in their flavor, which pro-
motes the flow of the digestive juices. As the constituents of meat
extracts are largely in a form ready for elimination, Rubner e holds
that they have little food value.

Pfeiffer, Einecke, and Schneider / have fed asparagin to cows and
report a favorable effect on the milk and its constituents, and W.
Yoltz^ claims asparagin can replace proteid without lowering the
quality of the milk and that it acts as a proteid sparer in herbivora.
In omnivora its proteid sparing power is small and it seems to have
no such power in carnivora but rather increases proteid cleavage.
In feeding experiments with mice on a zein ration Willcock and Hop-
kins * found that on adding tryptophane to the ration the lives of the
mice were lengthened. Henriques and Hansen* have maintained
nitrogenous equilibrium on feeding hetero-albumose.

Rubner i discusses the alcohol-soluble and alcohol-insoluble por-
tions of fluid beef. The nutritive value of fluid beef is considered at
length and the author concludes that if enough of such product for an
entire ration were taken the cost would be enormous. The claim that
two teaspoonfuls of fluid meat have a nutritive value equivalent to
one and one-fourth pounds of cooked meat is deemed correct. Two

a Arch. Hygiene, 1904, 51:1.

»Ibid, p. 19.

cj. Physiol., 1905, &*: 106.

d Stoffwechsel, 1882, p. 449.

«Zts. Biol., 1883, ^9:343.

/Mitt, landw. Inst, konigl. Univ. Breslau, 1905, 5:179.

^Fuhlings landw. Ztg., 1905, 54 (2) :41; (3) : 96.

fcj. Physiol.. 1906, 35: 88.

<Zts. physiol. Chem., 1906, 48: 383.

iZts. Biol., 1879, 15:485.

43689— Bull. 114—08 4

50 MEAT EXTRACTS.

teaspoonfuls of fluid meat weigh about 52 grams and are equivalent
to 65 grams of pure meat free from fat and bones. Barker a recently
published a thorough review of the question and has taken up several
new points. In normal man the amido bodies do not appear in the
urine to any extent; therefore, they must be of value, and the author
believes they are synthesized into protein by the cells of the small
intestine. W. Yoltz b claims that amido bodies of different chemical
constitution produce varying effects on the nitrogen and caloric bal-
ances of the body. The tightly bound NH2 groups, holding an inter-
mediate position in the molecule, such as are found in glycocoll, tend
to increase the nitrogen retention less than the carboxyl NH2 groups,
which are more easily separated from the molecule. The amids in an
ordinary diet give more favorable results than when fed alone. On
feeding various amids to dogs the author obtained favorable results.

An unsigned article in the Pharmaceutische Zeitung c discusses the
manufacture of meat extracts, and says that when meat (fat and bone
free) is extracted with water by heating, the extract does not taste
like the commercial meat extract, and is whitish, but after continued
heating over an open fire and the addition of 30 per cent of salt, the
commercial product, a brown aromatic extract with a characteristic
taste, is obtained. In preparing meat juice, 1 pound of meat cut up
and pressed yields 60 to 100 grams of a red-colored juice. Evaporate
this at 60° C. in a vacuum to one- third its bulk and a slightly red
solution with a taste of meat, but no salty taste, is obtained — a
product differing from the commercial article. It contains 30 per
cent of coagulable nitrogen. If a little of the solid commercial meat
extract is added, we have the commercial meat juice. This article is
answered by L. Geret,d who tells of the virtues of Liebig's extract.
H. Otto e claims that meat extracts contain no nutriment, and that the
fine odor and aroma of meat bouillon is destroyed in the commercial
product.

The nutritive value of beef preparations is also discussed by Chit-
tenden/ Liebig's and Armour's extracts were analyzed and found to
consist largely of soluble extractives and inorganic salts of muscle
tissue. The nitrogen is high but not to any extent available for the
body's use, and according to Kemmerlich an animal fed on extract of
beef will succumb quicker than an animal not fed at all. Extracts are
useful on account of their stimulating and restorative value. The
content of potash salts causes a quickened and stronger heart beat.
An extract of beef is more like an alcoholic stimulant than a food.
Meat juices such as Wyeth's and Valentine's, according to Chitten-
den, have little food value, resembling dilute meat extracts.

"British Med. J., Oct. 27, 1907. 'Ml.id., p. 316.

b Arch. ges. Physiol., 1906, 112:413. « Ibid., p. 350.

c Pharm. Ztg., 1905, 50 : 197. /Med. News, 1891, 58 : 716.

NUTRITIVE VALUES. 51

The explanation of the oxidation of the various amido acids in the
body is now generally referred to the relative position and number
of carbon atoms in the side chains. Schotten,a Pohl,6 and Knoopc
have investigated this point quite thoroughly. The extent to
which the administration of various amido acids will maintain the
nitrogen equilibrium was first investigated by Loewi,d who showed
that the end products of digestion which no longer gave the biuret
reaction are still able to replace the albumins destroyed during
metabolism.

Abderhalden and Bergelle have shown that amido acids when
given in moderate amounts (glycocoll up to 5 grams; alanin, 3 grams;
leucin, 8 grams; phenylalanin, 3 grams) are completely destroyed in
the body. Stolte^ injected various amido preparations into a rabbit
and found an increased urea output in all cases. According to Mann 0
the first change which the amido acids undergo in the body is prob-
ably that of oxidation, oxy-acids being formed as occurs in plants
and in alcaptan-urea when tyrosin and phenylalanin are changed
into homogentisinic acid. It is an open question whether the carbon
chain, after the splitting off of the nitrogen which forms urea, breaks
up still further or whether it is utilized in the building up of other
nonnitrogenous substances, such as carbohydrates and fats. Wohl-
gemuth h by feeding rabbits with the inactive or racemised mono-
amido acids (such as tyrosin, leucin, aspartic acid, and glutaminic
acid) found that the inactive acids become dissociated during meta-
bolism in such a way that the component occurring normally in the
body is oxidized as far as it can be assimilated while the abnormal
component is excreted partly or completely in the urine.

The occurrence of monoamido acids in the urine during normal
and pathological conditions has been studied by Abderhalden/' Ab-
derhalden and Bergell/' Ignatowski,* Abderhalden and Barker/ and
Erben.m Loewi and Neubergn have studied the diamins of the urine.
Since the discovery of the enzym erepsin in the intestine the idea is
rather generally accepted that the proteid molecule is broken down
in part, at least to the ammonia stage, and the ammonia and other
groups are synthesized into the characteristic body protein through
the agency of the epithelial cells of the villi of the small intestine and
transported by the lympocytes through the blood stream to the
tissues,

a Zts. physiol. Chem., 1883, 8 : 60. h Ber. d. chem. Ges., 1905, 38 : 2064.

b Arch, exper. Path. Pharm., 1896, 37: 413. i Zts. physiol. Chem., 1903, 38 : 557.

« Hofmeister's Beitrage, 1904, 6 : 150. 1 Ibid., 1903, 39 : 9, 464.

d Arch, exper. Path. Pharm. , 1902, 48: 303. * Ibid. , 1904, tf : 371.

« Zts. physiol. Chem., 1903, 39:9. I Ibid., 1904, 42 : 524.

/ Hofmeister's Beitrage, 1903, 5:1b. m Ibid., 1904, 43 : 320.

9 Chemistry of the Proteids, 1906. n Ibid., 1904, 43 : 355.

52 MEAT EXTRACTS.

In a recent article on the physiological action of muscle extracts,
J. G. Sladea states that muscle extracts were formerly supposed to
represent the whole nutritive value of the meat, but recently all
nutritive power has been denied them, and indeed, except for such
traces of albumin, fat, or peptone as they may contain, it is difficult
to see whence such food value would come. This author concludes
that muscle extract has no stimulating effect upon man's central
nervous system nor upon the power of performing physical work. If
taken as a strong solution or in large amounts it is liable to cause pur-
gation. In moderate doses it stimulates the action of the heart.
This is not due to kreatin, xanthin, or urates. The movement of the
plain muscles throughout the body is increased, which is probably
due to ornithin and novain. Muscle extract in 0.5 per cent solution
ir creases the power of the voluntary muscle, in 0.1 per cent solution
it has no effect upon the efficiency of the muscle, and in 0.2 per cent
solution this is decreased. Xanthin has an action corresponding to
the first effect; that is, in saturated solution it increases the efficiency.
Kreatin has no action on voluntary muscle. The effect of fatiguing
a muscle before preparing an extract from it is to increase its extract-
ives and increase the activity of the extract. If injected into ani-
mals it causes great languor, prostration, and all the symptoms char-
acteristic of fatigue. Muscle extract administered as "beef tea"
acts as a moderate diuretic to men and other animals. The diuresis
is associated with vasodilatation of the kidney.

Dr. O. Dornbluth6 discusses the preparation and composition of
various meat extracts, powders, and other preparations. Nutrose
and milk casein products are considered.

Dr. J. Price c gives a recipe for preparing home-made meat extract
after the general plan of Liebig's original recipe. He considers that
meat extract or juice prepared as he describes it is highly nutritious.

A. Brestowskid claims that meat extracts possess no food value,
but on account of the meat bases, potassium phosphates, and their
flavor they have value in increasing muscle activity and the secretion
of the gastric juice. The food and therapeutic value of peptones is
discussed.

Pawlow e says that muscle extract is a stimulant to an exhausted sys-
tem and assists digestion. Pawlow has shown that muscle extracts
are stomach stimulants and cause a flow of gastric juice. He found
also that the individual extractives, such as kreatin and kreatinin, were

a J. Physiol., 1907, 85 (3): 163.
&Aerztliche Monatschrift, 1898, 2 :49.
c Philadelphia Polyclinic, 1894, p. 93.
d Medicin.-Chir. Centrbl., 1893, 2<?:653.

eThe Work of the Digestive Glands, 1897, translated from the Russian by W. H.
Thompson, London, 1902.

NUTRITIVE VALUES. 53

ineffectual, and concluded that the specific substance causing the
stimulation was not known.

Brunton0 makes the following statement in regard to the effect of
beef tea or beef essence:

We find only too frequently that both doctors and patients think that the strength is
sure to be kept up if a sufficient quantity of beef tea can only be got down; but this
observation, I think, raises the question whether beef tea may not very frequently be
actually injurious, and whether the products of muscular waste which constitute the
chief portion of beef tea or beef essence may not under certain circumstances be actu-
ally poisonous. For although there can be no doubt that beef tea is in many cases a
most useful stimulant, one which we find it very hard, indeed, to do without, and
which could hardly be replaced by any other, yet sometimes the administration of
beef tea, like that of alcoholic stimulants, may be overdone, and the patient weak-
ened instead of strengthened.

Mays6 asserts that beef tea is entitled to be called a nutrient
because its action is the same as that of milk, or a 2 per cent solution
of ox blood. In a later paper c he ascribes this nutritive value to the
kreatin and kreatinin present.

Dr. Lehman d discusses the action and the toxicity of meat extracts
and concludes that Liebig's extract is not a heart poison, but is rather
an aid to the heart. Both in health and in sicknesss as much of the
extract can be used by the body as the stomach can stand. Home-
made meat extracts contain more potash than equivalent amounts of
Liebig's extract.

Dr. Carl Voit e gives a very able discussion of meat preparations
and considers them of great value as a condiment, but not as a food.

Dr. N. G. Vis/ conducted a set of experiments on men, using a
mixed diet, including beefsteak in the first period. For the beefsteak
he substituted in the second period an equivalent amount of nitrogen
in the form of sanatogen, a sodium-casein-glycerol-phosphoric-acid
compound. There was an increased excretion of nitrogen in both
urine and feces in the second period.

Frentzel and Toriyama 0 in opposition to Rubner find that of the
proteid-free extractive material of meat about two-thirds takes part
in metabolism in that it furnishes energy to the body.

Dr. Emil Burgi7' has studied the question of the heat and energy
value of meat and meat extractives in the case of dogs. His results
show that meat itself is a much more valuable source of energy than
are the meat extractives.

"The Practitioner, 1880, £5:325.

b The Lancet, 1886, 7:510.

clbid., 1887, 1:257.

<* Aerztliches Intelligenz, 1885, 32:318.

eMiinchener medic. Wochenschr., 1897, 44:221.

/Ibid., 1898,45:257.

ffAxch. Anat. Physiol., Physiol. Abt., 1901, p. 499.

>*Arch. Hyg., 1904, 51:1.

52 MEAT EXTKACTS.

In a recent article on the physiological action of muscle extracts,
J. G. Sladea states that muscle extracts were formerly supposed to
represent the whole nutritive value of the meat, but recently all
nutritive power has been denied them, and indeed, except for such
traces of albumin, fat, or peptone as they may contain, it is difficult
to see whence such food value would come. This author concludes
that muscle extract has no stimulating effect upon man's central
nervous system nor upon the power of performing physical work. If
taken as a strong solution or in large amounts it is liable to cause pur-
gation. In moderate doses it stimulates the action of the heart.
This is not due to kreatin, xanthin, or urates. The movement of the
plain muscles throughout the body is increased, which is probably
due to ornithin and novain. Muscle extract in 0.5 per cent solution
ir creases the power of the voluntary muscle, in 0.1 per cent solution
it has no effect upon the efficiency of the muscle, and in 0.2 per cent
solution this is decreased. Xanthin has an action corresponding to
the first effect; that is, in saturated solution it increases the efficiency.
Kreatin has no action on voluntary muscle. The effect of fatiguing
a muscle before preparing an extract from it is to increase its extract-
ives and increase the activity of the extract. If injected into ani-
mals it causes great languor, prostration, and all the symptoms char-
acteristic of fatigue. Muscle extract administered as "beef tea"
acts as a moderate diuretic to men and other animals. The diuresis
is associated with vasodilatation of the kidney.

Dr. O. Dornbliith6 discusses the preparation and composition of
various meat extracts, powders, and other preparations. Nutrose
and milk casein products are considered.

Dr. J. Price c gives a recipe for preparing home-made meat extract
after the general plan of Liebig's original recipe. He considers that
meat extract or juice prepared as he describes it is highly nutritious.

A. Brestowskid claims that meat extracts possess no food value,
but on account of the meat bases, potassium phosphates, and their
flavor they have value in increasing muscle activity and the secretion
of the gastric juice. The food and therapeutic value of peptones is
discussed.

Pawlow e says that muscle extract is a stimulant to an exhausted sys-
tem and assists digestion. Pawlow has shown that muscle extracts
are stomach stimulants and cause a flow of gastric juice. He found
also that the individual extractives, such as kreatin and kreatinin, were

a J. Physiol., 1907, 35 (3): 163.
*>Aerztliche Monatechrift, 1898, 2 :49.
c Philadelphia Polyclinic, 1894, p. 93.
d Medicin.-Chir. Centrbl., 1893, 28:653.

eThe Work of the Digestive Glands, 1897, translated from the Russian by W. H.
Thompson, London, 1902.

NUTRITIVE VALUES. 53

ineffectual, and concluded that the specific substance causing the
stimulation was not known.

Brunton0 makes the following statement in regard to the effect of
beef tea or beef essence :

We find only too frequently that both doctors and patients think that the strength is
sure to be kept up if a sufficient quantity of beef tea can only be got down: but this
observation, I think, raises the question whether beef tea may not very frequently be
actually injurious, and whether the products of muscular waste which constitute the
chief portion of beef tea or beef essence may not under certain circumstances be actu-
ally poisonous. For although there can be no doubt that beef tea is in many cases a
most useful stimulant, one which we find it very hard, indeed, to do without, and
which could hardly be replaced by any other, yet sometimes the administration of
beef tea, like that of alcoholic stimulants, may be overdone, and the patient weak-
ened instead of strengthened.

Mays6 asserts that beef tea is entitled to be called a nutrient
because its action is the same as that of milk, or a 2 per cent solution
of ox blood. In a later paper c he ascribes this nutritive value to the
kreatin and kreatinin present.

Dr. Lehman d discusses the action and the toxicity of meat extracts
and concludes that Liebig's extract is not a heart poison, but is rather
an aid to the heart. Both in health and in sicknesss as much of the
extract can be used by the body as the stomach can stand. Home-
made meat extracts contain more potash than equivalent amounts of
Liebig's extract.

Dr. Carl Voit e gives a very able discussion of meat preparations
and considers them of great value as a condiment, but not as a food.

Dr. N. G. Vis^ conducted a set of experiments on men, using a
mixed diet, including beefsteak in the first period. For the beefsteak
he substituted in the second period an equivalent amount of nitrogen
in the form of sanatogen, a sodium-casein-glycerol-phosphoric-acid
compound. There was an increased excretion of nitrogen in both
urine and feces in the second period.

Frentzel and Toriyama^ in opposition to Rubner find that of the
proteid-free extractive material of meat about two-thirds takes part
in metabolism in that it furnishes energy to the body.

Dr. Emil Burgift has studied the question of the heat and energy
value of meat and meat extractives in the case of dogs. His results
show that meat itself is a much more valuable source of energy than
are the meat extractives.

a The Practitioner, 1880, £5:325.

b The Lancet, 1886, i:510.

clbid., 1887, 1:257.

<* Aerztliches Intelligenz, 1885, «?2:318.

«Miinchener medic. Wochenschr., 1897, 44:221.

/Ibid., 1898,45:257.

9 Arch. Anat. Physiol., Physiol. Abt., 1901, p. 499.

ft Arch. Hyg., 1904, 51: 1.

54 MEAT EXTRACTS.

E. Kemmericha made a study of South American meat extracts
and peptones, and divides the proteid bodies of these substances into
three groups, depending on their action in the presence of various per-
centages of alcohol : (1 ) gelatin substances precipitated by 50 per cent
alcohol; (2) albumoses precipitated by 80 per cent alcohol; (3) the
peptones remaining in solution. The extractives are also in solution
with the peptones. The author suggests a separation based on the
fact that the extractives and salts dialyze while the other bodies
do not.

Frentzel and Schreuer6 fed meat extracts to dogs and compared
the results with those obtained when meat was fed. These authors
believe that the proteid-free extractives of meat, to one-third of their
total, take part in metabolism in that they produce heat and energy.

Dr. J. Forster c discusses Valentine's meat juice, and considers it
of no more value than Liebig's as a food — that is, it is of value as a
condiment.

Dr. R. Sendtner d gives analyses of some 12 meat extracts and
bouillon extracts. He considers the original Liebig process extract to
be the best and cheapest. Many of the bouillons and juices are
diluted meat extracts.

Frentzel and Schreuer e have studied the calorific value of meats
and meat meal. Dogs were used in the experiments. His results
agree with Ilubner's in showing that the calorific value of meat is
higher than that of meat powders and extractives.

Dr. Jung' in an article on meat extracts and peptones discusses the
various constituents of these bodies and methods for separating the
same. The author believes that large amounts of gelatin and gelatin
hydration products are present in some extracts, being included under
the term ''proteid" since no method for separating gelatin and its
hydration products from the various proteid bodies is known.

CONCLUSION.

It is commonly assumed that proteids, gelatinoids, and the simpler
amids have very different nutritive values, and, while all authorities
would agree in assigning the highest value to the first of these, there is
probably no small difference of opinion as to the order in which the sec-
ond and third should be rated. In considering such a question, there
should be separately taken into account relative digestibility or solu-

oZts. physiol. Chem., 1893, 18A09.
b Biedermann's Centrbl. Agr. Chem., 1902, «?/:391.
cZts. Biol., 1876, 12:475.
^ d Arch. Hyg., 1897, 6:253.

cArch. Anat. Physiol., 1901, p. 284.
/Chem. Ztg., 1900, 94 : 732.

XUTRTTTVi; VALUES. 55

bility, capability of undergoing osmotic absorption, and oxidizability
for the production of energy. At present, no definite numerical state-
ment of the relative nutritive values of nitrogenous bodies of these
three classes can be made. It seems much to be desired that more
extended experiments than have so far been recorded should be made
upon living animals (as far as possible upon human beings) to deter-
mine the utilization of both the gelatinoids and the simpler amids.
The latter no doubt undergo oxidation to some extent in the animal
body, and produce some energy in consequence. It is probably true
of these simpler amidic substances that much larger quantities than
analysis exhibits as constituents of the food consumed, or than analy-
sis detects among the residue of food rejected from the body without
having undergone complete oxidation, may be constantly formed
among the earlier products of the metabolism of the proteids, and
afterwards themselves undergo further change into the simpler and
more stable forms of carbon dioxid, water, and urea.

In the animal body the amido acids are acted upon in two ways;
that is, they are converted into the corresponding fixed acids or car-
bonic acid is split off, leading to the formation of Brieger's diamins,
or it is possible for both of these processes to take place. Usually the
albumins are converted in the alimentary tract by the four proteo-
lytic ferments (pepsin, trypsin, erepsin, and arginase) into primary
crystalline dissociation products, namely, the amido acids, which are
absorbed in this form. Whether a part of the albumin taken as food
can or can not be absorbed in the form of albumoses, peptones, and
peptids remains to be determined.

Meat preparations of the sort included in this report are largely
used by the sick and the young. Their use is recommended fre-
quently by physicians who may not have taken the trouble to ascer-
tain the true nutritive value of the product prescribed. It seems to be
the general consensus of opinion among scientific investigators who
have studied this question that the food value of these meat extracts
is rather limited, and although they are a source of energy to the
body they must not be looked upon as representing in any notable
degree the food value of the beef or other meat from which they are
derived. When prepared under the best possible conditions a com-
mercial meat extract is, of necessity, in order that it may not spoil,
deprived of the greater part of the coagulable proteids, which con-
stitute the chief nutritious elements of the juice. It is fair to state
that many manufacturers make no claim as to the food value of their
preparations, only a comparatively few making extravagant state-
ments as to the nutritive value of these products.

Preparations of this character are not wholly valueless in the sick
room, for they possess stimulating qualities, and in the kitchen they

56

MEAT EXTRACTS.

are useful on account of their flavoring properties. They are not,
however, concentrated foods, having on the contrary but compara-
tively little nutritive value. The meat juice prepared from fresh
meat, in the home or hospital, by continued heating at a low tem-
perature, is far superior as a food to the commercial meat extracts
and so-called meat jukes.

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