UNIVERSITY OF CALIFORNIA

COLLEGE OF AGRICULTURE

AGRICULTURAL EXPERIMENT STATION

BERKELEY, CALIFORNIA

CIRCULAR 349

October, 1941

UTILIZATION OF CALIFORNIA FRUITS

W. V. CRUESS1 and G. L. MARSH2

For a number of years, the markets have not been able to absorb the
supply of most kinds of California fruits at prices that are profitable to
the grower, and frequently large surpluses have been allowed to go to
waste. The causes for this situation are several, among which may be
mentioned overplanting stimulated by post-War high prices ; increased
competition with fruits and fruit products of other regions, for example,
pineapple products; decreased buying power of consumers owing to the
depression ; and changing fruit food habits, for example, use of certain
fruit juices instead of certain other canned or stewed fruits. Because of
this situation the California Agricultural Experiment Station receives
numerous requests for information and advice concerning utilization of
surplus fruits. The present circular has been prepared to answer such
requests.

It has been stated that foods are competitive for a place on the table
and in the human stomach. Human intake of food, expressed on the
calorie basis, is rather inelastic, other things being equal. Yet, the per-
capita consumption of fruits of all kinds expressed upon the fresh basis
is only about 206 pounds a year,3 or about 3.7 per cent of the total food
intake per capita on a calorie basis, assuming an average value of fruits
on the fresh basis of 200 calories per pound and an average total require-
ment of 3,000 calories per day per person.4 It would seem that American
consumers could use more fruits without seriously upsetting the economy
of staple foods, such as cereal products, dairy products, sugars, and
meats.

1 Professor of Fruit Technology and Chemist in the Experiment Station.

2 Associate in the Experiment Station.

3 Shear, S. W. Deciduous fruit statistics. University of California Giannini Founda-
tion Mimeo. Rept. 69:16. 1940.

4 Atwater, A. O. Principles of nutrition and nutritive value of food. U. S. Dept.
Agr. Farmers' Bui. 142:1-48. 1902.

[1]

2 University of California — Experiment Station

The present circular is based largely upon the results of investigations
made at this station during the past twenty-five years. The information
is presented according to products, such as unf ermented beverages and
sieved fruits, rather than according to the different varieties of fruits.

References. — Most of the journal articles cited in this circular can
be consulted in any well-equipped library. This station does not have
these articles for distribution. The bulletins of various agricultural
experiment stations can be obtained from the stations issuing them,
sometimes for a small charge if the publications are not out of print. If
they are out of print, they may be consulted in the bound volumes in
many of the larger libraries. The available United States Department
of Agriculture publications can be had for small sums in coin or money
order (stamps are not accepted) from the Superintendent of Documents,
Washington, D. C. Those that are out of print will be found in bound
sets in libraries. We have attempted to indicate the various station and
United States Department of Agriculture publications out of print at
the time this circular goes to press.

PRESENT DISPOSAL OF CALIFORNIA FRUITS

Shear (see footnote 3, p. 1) has prepared the statistics given in table
1 to indicate in a general manner the present outlets for California fruits.

The total quantity of oranges used commercially for processed prod-
ucts, according to Shear, was 126,238 tons a year for the period 1934-
1938. About 25,000 tons of this total are canned as juice, the average for
the period in question being about 750,000 cases annually. A consider-
able tonnage is utilized for bottler's sirups, orange concentrate, and
dairy-base sirups. Some oranges are used for essential oil and for dried
stock feed. An unknown quantity is not utilized in any manner and is
dumped on the cull heaps in the citrus areas. The above uses comprise a
relatively small proportion of the total orange production. It must be
remembered, however, that a very large proportion, probably more than
50 per cent, of the oranges sold fresh are used in juice stands, restaurants,
in the home, and elsewhere, for juice consumed fresh.

Grapes designated "otherwise processed" in table 1 are those crushed
commercially for wine. Practically all of the wine grapes shipped fresh,
namely, 161,960 tons annually for the 1934-1938 period, were utilized
for the making of wine in the home. Most of the table and raisin grapes
"otherwise processed" were crushed for wine.

Most of the apples "otherwise processed" were utilized for fresh juice
and vinegar, small amounts being utilized for hard cider, brandy, apple
wine, boiled cider, and apple butter.

Cir. 349]

Utilization of California Fruits

Most of the 11,025 tons of cherries "otherwise processed" were barreled
in brine containing sulfur dioxide and lime. These were utilized for
preparation of Maraschino cherries, principally for addition to canned
fruits for salad and canned fruit cocktail.

With the exception of 1939, all of the apricots grown were harvested;
Shear estimates that about 9,000 tons were not picked in 1939.

TABLE l*

Harvested Production and Utilization of California Fruits on a Fresh

Basis; Average 1934-1938

Kind of fruit

Total fruits

Deciduous, total

Grapes, total

Deciduous tree, total

Citrus, total

Deciduous tree:

Apples

Apricots

Cherries

Figs

Peaches

Pears

Plums

Prunes

Grapes:

Wine

Table

Raisin

Citrus :

Oranges

Lemons

Grapefruit

Harvested

tons
5,558,880

3,941,752

2,118,600

1,823,152

1,617,128

206,592

216,000

20,360

86,900

482,400

219,800

60,600

530,500

558,200

371,600

1,188,800

1,237,761

325,037

64,330

Dried

tons

1,875,868

1,875,868

881,520

994,348

0

72,648

143,640

0

76,260

139,300

32,000

0

530,500

6,160
874,400

Canned

(other than

orange

j uice)

tons
399,953

399,953

4,060

395,893

0

528

54,320

3,420

5,025

265,060

65,700

1,840

0

0

0

4,060

Otherwise

tons
943,756

757,523

736,800

20,723

186,233

14,

0
915
0
0
0
0
0

395,280
160,920
180,600

126,238
55,723
4,272

Used as
fresh fruit

tons
2,339,303

908,408

496,220

412,188

1,430,895

118,608

18,040

11,025

5,615

78,040

122,100

58,760

0

161,960
204,520
129,740

1,111,523

269,314

50,058

* From: Shear, S. W. Deciduous fruit statistics. University of California Giannini Foundation Mimeo.
Rept. 69:6. 1940.

A large proportion of the figs after drying were converted into dried
fig paste for use by bakers, confectioners, and cracker manufacturers.

Of the total fig production, about 5,900 tons on the dry basis, or about
20 per cent of the crop, was unmerchantable each year. Most of this was
unfit for human consumption and was used for stock food.

4 University op California — Experiment Station

Most of the freestone peaches were harvested each year and utilized
for drying, canning", and fresh sale; but in 1938 about 21,000 tons and in
1939 about 9,000 tons of clingstone peaches were not utilized. In 1935,
1936, and 1937, all of the clings were harvested. An average of about
35,900 tons of clings were dried each year.

All of the Bartlett pear crop was harvested in 1935 and 1936. In 1937
about 10,000 tons, in 1938 about 20,000 tons, and in 1939 about 5,000
tons of Bartlett pears were not harvested.

Similar data for other fruits are difficult to secure or to estimate. The
production of most California fruits at present, however, is in excess of
the quantity that can be marketed at reasonable profit under existing
economic and world political conditions.

UNFERMENTED BEVERAGES

One of the most important outlets for certain fruits is their use in
various unfermented beverages. These are chiefly fresh, canned, and
bottled juices, bottled carbonated beverages (fruit soda waters), so-
called "dairy-base beverages," beverages made from dried fruits, and
fountain beverages. The dairy and fountain beverages are prepared
from sirups and concentrates.

In view of the continued increase in consumption of unfermented
fruit juices, they should utilize an increasing proportion of the surplus
of certain fruits.

Fresh Juices. — Practically all lemons and limes sold fresh are used for
the preparation of lemonade and limeade, or added in the fresh condition
to various mixed beverages. Much of the orange crop is used in the home
or in juice stands, restaurants, hotels, hospitals, and other establishments,
for preparing juice for immediate consumption in the fresh state. Many
thousands of tons of apples are crushed and pressed for juice sold fresh.

Freshly prepared juices are superior in flavor and aroma to those
preserved in any manner. The principal obstacles to increased use of
fresh juices lie in cost of transportation of fresh fruits to distant centers
of population ; the relatively short season for some fruits ; and, except
for citrus fruits, the high cost and large size of equipment required for
extracting the juice.

If inexpensive, simple, small-sized, easily cleaned devices for extract-
ing apple, grape, and berry juices were made available and popularized
for home and juice-stand use, it is likely that consumption of the fresh
juices could be increased materially. The growers' associations have
popularized such devices for preparation of citrus juices with very great
benefit to their industry. This fact is of particularly great importance

Cm. 349] Utilization of California Fruits 5

to the growers and shippers of Washington Navel oranges ; for the juice
of this fruit has proved, to date, unsuitable for canning or bottling,
owing to its strong tendency to undergo rapid adverse changes in flavor
and quality after extraction.

In Europe fresh grapes and fresh grape juice are used in important
quantities in the so-called "grape cure." That is, many of those suffering
from digestive disturbances, nervous disorders, alcoholism, or certain
other ailments go to the grape districts and for a period of several weeks
live chiefly on fresh grapes and grape juice. It is specified that the juice
must be consumed immediately after pressing, a recommendation sup-
ported by scientific evidence that vitamin C is very rapidly oxidized in
fresh juice and that vitamin Bx decreases rather rapidly on standing of
the juice. The grape cure seems to have some scientific basis since most of
the ailments treated by it are due to Bx deficiency.

Perhaps American producers and shippers of fresh grapes could in-
troduce this European custom to America with advantage.5 But, it would
probably be necessary to secure further experimental evidence on the
dietary value of grapes. They are known to be a fair source of vitamin
Bx, a good source of G (riboflavin) , and to exert a strongly basic reaction
in the system.

While orange, apple, and grape juices probably will remain for some
time to come the most important of juices for fresh use, it is possible
that pomegranate, Logan and Boysen blackberries, and certain other
fruits might attain some favor for this purpose.

Bottled Juices. — Since the bottling of juices is thoroughly covered in
Circular 344 of this station6 and in other publications, it will be presented
only very briefly here.

Grape juice will be considered first and the other bottled juices com-
pared with it. California packs very little grape juice, because of the
scarcity of the Concord and other eastern juice varieties. The investiga-
tions of this station, however, show that a desirable juice can be made
from California vinif era grapes.

The preparation of grape juice in the eastern United States is des-
cribed by Tressler, Joslyn, and Marsh/ and by Tressler and Pederson,8
to whose publications the reader is referred for details.

Based upon the investigations made by this station, the procedure
recommended in Circular 344 is suggested for the preparation of bottled

5 Anonymous. Fruit juice for heart disease. Food Industries 12(2) :95. 1940.

6 Joslyn, M. A., and G. L. Marsh. Utilization of fruit in commercial production
of fruit juices. California Agr. Exp. Sta. Cir. 344:1-63. 1937.

7 Tressler, D. K., M. A. Joslyn, and G. L. Marsh. Fruit and vegetable juices, xii +
549 p. Avi Publishing Co., Inc., New York, N. Y. 1938.

8 Tressler, D. K., and C. S. Pederson. Preservation of grape juice. II. Factors
affecting the rate of deterioration of bottled Concord juice. Food Kesearch 1:87-97
1936.

6 University of California — Experiment Station

white and bottled red juices from California grapes. Additional details
are given in some less readily available publications.9

Bottled apple juice is usually brilliantly clear, a condition that re-
quires special treatment. The apples used should be of rich flavor and
tart. The Winesap, Stayman Winesap, and Spitzenburg (Esopus Spit-
zenburg) have proved satisfactory in our tests.10 If picked at the proper
stage of maturity, the Gravenstein gives a pleasing juice. The Yellow

Fig. 1. — A continuous juice extractor. (Courtesy of
American Utensil Co., Food Industries photograph.)

Newtown is also of fair quality for juice. The procedure described in
Circular 344 (see footnote 6, p. 5) is recommended.

Logan and Boysen blackberry and other berry juices may be packed
as described in Circular 344. These juices should be sweetened before
bottling in order to retain their fresh flavor. They are diluted with water
at the time of serving. Figure 1 illustrates a suitable juice extractor.

9Cruess, W. V. Unfermented fruit juices. California Agr. Exp. Sta. Cir. 220:1-32.
1920. (Out of print; replaced by Circular 344, cited in footnote 6.)

Cruess, W. V., and J. H. Irish. Fruit beverage investigations. California Agr. Exp.
Sta. Bui. 359:526-68. 1923. (Out of print.)

Cruess, W. V., and L. Cash. Canning of California grape juice. Fruit Products
Journal 15:357-58, 364, 373. 1936.

10Celmer, E. E., and W. V. Cruess. Experiments on the canning of apple juice.
Fruit Products Journal 16:356-59, 379. 1937.

Cir. 349] Utilization of California Fruits 7

Circular 344 discusses the problems of flavor retention in citrus juices
and describes modern procedure based largely on the research of this
station.

Pomegranates yield a very good juice useful in mixing with other
juices. At present there is practically no market for this fruit. See
Circular 344 for procedure.

The utilization of surplus prunes is at present the most serious eco-
nomic problem in California fruit industries. Our recent studies have
developed a procedure that gives a beverage of superior flavor. As this
process is not given in Circular 344, it is presented briefly here.

Prunes of the present or last season's crop and of superior quality
must be used. Small inferior prunes are fit only for stock feed. The
prunes are covered with water, heated to 175°-190° F and allowed to
stand 8-24 hours. The liquid is then drawn off and the extraction re-
peated with fresh water. In practice, three tanks would be operated in a
series as a diffusion battery and a single extract instead of three would
be obtained, as in extracting sugar from beets. The extracts are mixed
and diluted to 20° Balling with water, and citric acid added to taste.
It is heated to 175° F, bottled, sealed, and cooled. Under the food and
drug regulations, the product may not be termed a "juice." It may be
called "prune beverage" qualified by the words, "an extract of dried
prunes."

Plum juice, made from red or black or purple plums, or a mixture of
one of these with white plums, is pleasing in flavor and appearance.
Addition of sugar is usually necessary as with berry juices.

Peaches, pears, apricots, and certain other fruits do not give undiluted
juices suitable for bottling ; but pulpy bottled beverages may be made
as described in Circular 344.

Canned Fruit Juices. — In recent years the canning of fruit juices has
attained great importance, and now utilizes a considerable proportion of
the pineapples of Hawaii, the grapefruit of Florida and Texas, and the
oranges of California and Florida. We believe that canned apple juice
and canned beverages made from prunes and from apricots are suffi-
ciently pleasing in flavor and appearance and of such high dietary value
that they have the possibility of attaining great popularity.

The canning of these and other fruit juices is presented quite fully
in Circular 344 (cited in footnote 6, p. 5). The following additional
comments may, however, be helpful.

Gravenstein apples yield an excellent canned juice if the fruit is
allowed to reach full flavor on the tree and is not picked at the immature
stage customary for the fruit for eastern shipment. For best results the

8 University of California — Experiment Station

juice of the Yellow Newtown should be blended with that of a variety
of higher acidity and flavor such as the Winesap, Stayman Winesap, or
Baldwin. All apple juices rapidly lose their flavor and aroma in plain
tin cans; on the other hand, reenameled type-L cans, or cans lined with
so-called "apple-juice enamel" retain these qualities almost perfectly.
This station was the first to establish the fact that enamel-lined cans are
necessary for the retention of flavor in apple juice. (See footnotes 9 and
10, p. 6.)
In preparing canned prune beverage — that is, water extract of dried

Fig. 2. — Citrus-juice extraction and straining equipment. (Courtesy of
F. W. Bireley Company.)

prunes — the same precautions stressed for the bottled juice should be
observed ; namely, only prunes of high quality and of the current or the
last season's crop should be used and the extractions should be made at
not above 190° F. Small prunes give a juice of very undesirable flavor
and old prunes impart a tobaccolike odor and flavor to the juice. Such
fruit should not be used for human food in any form. Prune beverage
retains its flavor much longer and better in enamel-lined than in plain
tin cans.

While California canned grapefruit juice has been unable to compete
with that of Florida and Texas, it is possible that a blend of California
grapefruit and orange juices would be able to meet that competition
successfully. It is a very pleasing drink.

Cm. 349] Utilization of California Fruits 9

Other promising blends are orange juice and apricot puree, grape-
fruit juice and prune beverage, orange and carrot juice, grapefruit and
celery juice, and Boysen or Young blackberry and orange juice.

For methods to be followed in the extraction and canning of these
various juices, see Circular 344, cited in footnote 6 (p. 5) .

Frozen-Pack Juices. — It was found by Cruess, Overholser, and Bjar-
nason11 more than twenty years ago that various fresh juices frozen in
airtight containers and stored at 0° F retained their fresh character-

Fig. 3. — Continuous agitating heater for very rapid pasteurization of canned
juices. (Courtesy of Thermal Research Corporation.)

istics for at least two years. Eckart and Cruess12 reported that fresh
pineapple juice retained its quality fairly well in the frozen condition in
airtight containers. Tressler, Joslyn, and Marsh (see footnote 7, p. 5),
as well as Joslyn and Marsh (see footnote 6, p. 5) and others recom-
mend the preservation of fruit juices by freezing, when it is desired to
retain the juice in a nearly fresh condition for a considerable period.
Owing to the cost of freezing storage and the greater cost of transporta-
tion and distribution, the frozen-pack juices are somewhat more costly
than those preserved by the usual bottling and canning procedures.
Nevertheless, the method may attain importance for certain juices of

11 Cruess, W. V., E. L. Overholser, and S. A. Bjarnason. Storage of perishable
fruits at freezing temperature. California Agr. Exp. Sta. Bui. 324:1-20. 1920. (Out
of print.)

12 Eckart, T. G., and W. V. Cruess. Freezing storage of pineapple products. Fruit
Products Journal 10:364-66. 1931.

10 University of California — Experiment Station

delicate and unstable flavor. At present a moderate amount of orange
juice is preserved in this manner for retail sale, and large quantities are
so preserved in bulk for subsequent use in preparation of "dairy base" or
other products. See Circular 344 for details of freezing juices.

For institutional use and for a short storage period of two or three
weeks, paraffin-lined cardboard cups or tubs or friction-top cans may be
used. For prolonged storage, airtight containers are advised.

In sales trials made by this Division during the period 1920 to 1924,
a frozen-pack punch sirup proved very popular. It was prepared by
mixing aproximately 1 part of concentrated lemon juice, 1 part of con-
centrated orange juice, and 3 parts of a deeply colored, concentrated
juice or sirup, such as red-grape concentrate, pomegranate sirup, or
Logan or other blackberry sirup. The thoroughly mixed blend was packed
in paraffined cardboard, slip-cover, cylindrical cartons and stored at
0°-10° F. The consumer merely added water to the frozen sirup which on
melting chilled the drink. "With the better quality of fruit concentrates
now available, a product of this type should be well received. It could
be marketed through the regular frozen-pack food channels and ice
cream stores.

The punch sirup was also pasteurized in bottles in our tests and dis-
tributed in grocery stores without refrigeration. But its shelf life is then
rather short — probably not more than two months.

Beverage Sirups for Home Use (Squash Sirups). — In England and
in many of its possessions and dependencies, bottled fruit sirups are very
generally used in the home for preparing squashes by diluting the sirups
with plain or carbonated water. They are also used in mixed alcoholic
drinks.

The procedure for preparing and preserving the sirups is simple.
Sugar is added to the fresh juice to give a sirup of medium density, 60 °~
70° Brix, and it is preserved with sodium benzoate or sulfur dioxide or
by pasteurization at 175° F. Juices from fruits rich in pectin should be
treated with a pectic enzyme to prevent jelly formation.

In a recent visit to Egypt, it was observed that orange, lemon, lime,
pomegranate, grapefruit, strawberry, and mango squash sirups were
popular. The principal objection to such sirups is that the dilution of
5 or 6 to 1 with water before serving is so great that they use relatively
little fruit.

In experimental production and trial sales of fruit-beverage sirups for
home use by this station (Bulletin 359 ; see footnote 9, p. 6) , the beverages
were found to be much more satisfactory if the juices were sweetened only
enough to permit dilution with about 2 parts of water to 1 of sweetened

Cir. 349] Utilization of California Fruits 11

juice. Berry juices, sweetened apricot puree, and a sweetened mixture
of orange and lemon juices were satisfactory. See Shallah and Cruess.13

For further details of preparing and preserving squash sirups see
Charley and Harrison."

"Dairy-Base" Beverages. — Noncarbonated, sweetened, and diluted
unfermented orange drinks are now rather widely distributed in milk
bottles by milk dealers and others who prepare them from "dairy-base"
sirups. There should be a potential demand for other fruit beverages of
similar nature. The procedure for orange "dairy-base" sirups is de-
scribed in Circular 344 (cited in footnote 6, p. 5) .

Possibly, among California juices, undiluted prune beverage, and the
diluted beverages made from sweetened Boysen blackberry, apricot,
peach, and pomegranate juices might find favor as "dairy-base" drinks.
It would seem that apple and grape juices should be sold undiluted if
distributed as "dairy" beverages, for they are very low in cost and retain
their flavor well. They could be distributed by dairy delivery companies.

Concentrates. — Since concentrated fruit juices are used primarily for
the preparation of unfermented drinks rather than for other purposes,
they are included in this chapter.

The most common method of concentrating consists in boiling the
juice under a high vacuum in a vacuum pan ; preferably at a temper-
ature not above 120° F. For details see Tressler, Joslyn, and Marsh
(footnote 7, p. 5) , Charley and Harrison, Cruess,15 Irish,16 or other refer-
ence. The vacuum pan should be constructed of stainless steel, Monel
metal, Inconel alloy, or other alloy not attacked by the juice. Citrus and
apple juices should be deaerated and flash-pasteurized ; grape and berry
juices should be flash-pasteurized before concentration. Orange concen-
trate retains its flavor better if some sugar is added to the juice before
concentration. Vegetable juice concentrates can be made as described for
fruit concentrates.

Much of the volatile flavoring and aroma is lost in ordinary vacuum-
concentrating. In the Serailian process, the Pf audler ester impregnation
process, and in an improvement on these by Mottern,17 a portion of the
distillate containing the volatile constituents is collected and returned
to the concentrate.

13 Shallah A., and W. V. Cruess. Canning of apricot juice. Fruit Products Journal
13:205.1934.

14 Charley, V. L. S., and T. H. J. Harrison. Fruit juices and related products. Im-
perial Bureau of Horticulture and Plantation Crops, Technical Communication
11:1-103. 1939. (Price 5 shillings.)

13 Cruess, W. V. Commercial fruit and vegetable products. 2d ed. x 4- 798 p. McGraw-
Hill Book Company, Inc., New York, N. Y. 1938.

16 Irish, J. H. Fruit juice concentrates. California Agr. Exp. Sta. Bui. 392:1-20.
1925. Eevised 1931. (Out of print.)

17 Mottern, H. H. Concentrated apple juice. Fruit Products Journal 17:68-70. 1937.

12 University of California — Experiment Station

Juices may be concentrated by freezing out some of the water as ice
crystals and removing these in various ways; as by centrifuging, by
metal draper, or by screening. See Tressler, Joslyn, and Marsh (foot-
note 7, p. 5) ; Charley and Harrison (footnote 14, p. 11) ; or Cruess
(footnote 15, p. 11), for further details. The ultimate practical concen-
tration is about 50° Brix; whereas in a vacuum pan about 72° Brix is
readily attainable. In the freezing process, oxidation is severe ; there-
fore, the juices should be flash-pasteurized to destroy enzymes before
concentration. Cruess18 found that a very satisfactory concentrate was
obtained by blending concentrates made by freezing with those made by
vacuum concentration to give a product of 60°-65° Brix.

Concentrates are preserved with sodium benzoate, cold storage, or by
pasteurization. The second is the best of these.

They are used after diluting to beverage strength with water or after
diluting and sweetening. They are also useful in preparing sirups for
making carbonated beverages. See the next section.

They are, however, not so stable as squash sirups and are inclined to
darken rather rapidly and to change in flavor when stored at room
temperature.

Carbonated Beverages. — Several billion bottles of carbonated, non-
alcoholic beverages are consumed in the United States annually (Bulletin
359, cited in footnote 9, p. 6) . Extremely little of this total contains any
fruit juice. Some in the past has been flavored with so-called "true fruit
flavors," which are usually principally imitation fruit flavor. Fruit
beverages contain valuable dietary substances not found in the usual
carbonated beverage; for example, vitamins and certain mineral ele-
ments,

Since fruits are now abundant and low in cost and since the technology
of preparing carbonated beverages from them has been well developed,
there would appear to be no unsurmountable technical or economic diffi-
culty in increasing the use of fruits in these products.

During 1923 and 1924 the Fruit Products Laboratory of this station
produced carbonated fruit beverages on a small commercial scale and
sold them through grocery stores in the Oakland and Berkeley area in
order to test consumer opinion. The demand grew rapidly beyond the
capacity of the facilities. The retail prices were 10 cents for a single
7-ounce bottle, 15 cents for two bottles, and 75 cents for a dozen bottles,
plus the usual deposit for the empty bottles. The most popular beverages
were orange, red-grape blend, fruit punch (a blend of several juices),
lemon, Logan blackberry, and strawberry. The cost of producing the bev-

18 Cruess, W. V. Commercial production of grape syrup. California Agr. Exp. Sta.
Bui. 321:410-16. 1920. (Out of print.)

Cir. 349] Utilization of California Fruits 13

erages ranged from 2.07 cents a bottle for lemon to 3.50 cents for rasp-
berry beverage, exclusive of the cost of the bottle. The procedures used in
preparing and bottling the beverages were those developed in this lab-
oratory and described in Bulletin 359 (cited in footnote 9, p. 6). This
bulletin is now out of print but the information is presented fully by
Tressler, Joslyn, and Marsh (cited in footnote 7, p. 5).

Since completion of these sales trials, the commercial production of
carbonated beverages containing orange juice has increased ; and there
is increasing interest in other fruit beverages among bottlers.

In Holland and in Egypt, carbonated beverages of 25 to 50 per cent
fruit-juice content are produced. The juices were lightly sweetened,
diluted with water, carbonated at low temperature in bulk ; filled into
bottles of approximately 12-ounce size, sealed, and pasteurized at 140° F.
Pineapple, grapefruit, orange, and apple were most popular. It is our
belief that fruit beverages of this type have greater possibilities than
those that are highly diluted. It would be desirable for federal and state
food authorities to establish minimum fruit content for carbonated fruit
beverages.

Preservation of Juices by Chemical Preservatives. — Sodium benzoate,
benzoic acid, and sulfurous acid (sulfur dioxide, fumes of burning sul-
fur) are the only chemical preservatives permitted by law. Two new
preservatives are under consideration by the federal Food and Drug
Administration.

Much barreled and bottled apple juice is preserved in America with
sodium benzoate, and various juices and sirups are preserved in Great
Britain with sulfurous acid. Some orange "dairy base" and most soda
fountain sirups are preserved with benzoate.

There is a strong consumer prejudice against food products preserved
with benzoate because of the former practice of concealing spoilage and
inferiority by its use. At present, however, all juices and other products
so preserved are subject to strict governmental inspection and, hence,
are usually of good quality.

The usual concentration of sodium benzoate required for preservation
of juices is about 0.1 per cent by weight ; but Cruess, Richert, and Irish19
found that juices from thoroughly ripe fruits and therefore of sub-
normal acidity may require as much as 0.30 per cent. At 0.1 per cent
benzoate or higher, the juice possesses, to most consumers, a decided
"scratchy" or "burning" taste.

With sulfurous acid, such high concentration (0.1 per cent or more

19 Cruess, W. V., P. H. Eichert, and J. H. Irish. The effect of hydrogen ion concen-
tration on the toxicity of several preservatives to microorganisms. Hilgardia 6(10) :
295-314. 1931.

14 University of California — Experiment Station

as sulfur dioxide) must be used iu order to preserve juices permanently
that the flavor and odor are objectionable. It is valuable, however, in
lower concentrations for checking undesirable changes caused by oxida-
tion. For this purpose 0.02 per cent as sulfur dioxide is adequate. It is
not objectionable at this concentration. A combination of about 0.05
per cent benzoate and about 0.02 per cent sulfur dioxide maintains
orange and apple juices in a nearly natural condition for a considerable
period.

Preservation by Sterilizing Filtration. — In Switzerland and Ger-
many, much apple juice is preserved in sterile bottles by close filtration.
The process is in use also in Holland and England. It was devised by
Professor Boehi in Switzerland in 1912. For details of the procedure see
Charley and Harrison (cited in footnote 14, p. 11) .

In brief the procedure is about as follows : apples of suitable flavor
and maturity for juice are crushed and pressed. The juice is roughly
filtered and then filtered through a Seitz "germ-proofing" sterile pad
(or similar filter) and is conveyed by sterile equipment to an impregnat-
ing pump, where it is impregnated to about 120 pounds pressure with
carbon dioxide. It is pumped into sterile 5,000-10,000-gallon wax-lined
or glass-lined steel tanks previously freed of air. It is stored at 50°-54° F
under about 120 pounds carbon dioxide pressure. The few yeast cells and
mold spores that may be present are held in check by the carbon dioxide.

At the time of bottling the juice is drawn off. A small amount of the
carbon dioxide is left in the juice to render it faintly sparkling; but most
of the gas is allowed to evolve from the juice and is recovered and com-
pressed for future use. The juice is again close-filtered to remove all
yeasts and molds, bottled in bottles sterilized by heat and sulfur dioxide,
and sealed with sterile caps. It is not heated.

The juice is brilliantly clear and free of cooked taste, although the
flavor is altered perceptibly from that of the fresh.

In America the process and equipment would be much more costly
than are our usual methods of preservation, and the product would have
to command a higher price. Nevertheless, it might fill a possible limited
market to consumers who demand a brilliantly clear juice. As pre-
viously stated, the present trend in the United States is toward the
"natural" juices; that is, cloudy or pulpy juices canned, or bottled and
preserved by pasteurization. The "Seitz-Boehi cold process" has been
commercially used for apple juice in Washington state and to some
extent in California.

Other Methods of Preservation. — In the Katadyn process (see Charley
and Harrison cited in footnote 14, p. 11), a weak direct electric current

Cm. 349] Utilization of California Fruits 15

is passed through the juice between silver electrodes. Minute quantities
of silver are reported to be taken up by the liquid and are said to exert a
sterilizing and preservative effect. There appears to be much uncertainty
as to whether this procedure is permissible under American food and
drug regulations owing to the alleged presence of silver in the juice.

In the Matzka process, heat is applied in addition to an electrolysis
treatment between silver electrodes. According to Arengo-Jones of
Canada, who has investigated the process (see Charley and Harrison
cited in footnote 14, p. 11) , the Matzka process is essentially one of simple
pasteurization.

Ultraviolet light has been tested as a sterilizing agent for juices. It is
successful with white juice in thin layers, but causes undesirable changes
in flavor.

We have found that ultrasonic waves of high frequency can be used
to sterilize small quantities of juice but on a large scale have not proved
very effective; that is, complete sterilization is almost impossible of
attainment. In tests in this laboratory high-frequency electric current
and short radio waves failed to sterilize juices except by their heating
effect.

Powdered Juices. — Lemon and orange juices have been dried commer-
cially by the Merrill-Soule spray drying process and equipment. To these
and other fruit juices must be added corn sugar, milk sugar, milk, or
other agent that will prevent formation of a gummy mass or sirup. The
juices are rich in levulose, which is a very hygroscopic sugar and difficult
to dry to a powder. In the drying process a great deal of the fresh fruit
aroma and flavor is lost by volatilization, and the added sugar necessary
in maintaining a powder considerably increases the sweetness; hence
some juices should be acidified with fruit acid, such as citric, or with
lemon juice before drying. Tressler, Josyln, and Marsh (cited in foot-
note 7, p. 5) give details of equipment and procedure. Spray driers
other than the Merrill-Soule may be used ; for example, the well-known
Jensen-Gray spray drier.

Several years ago a simple procedure20 was devised in this laboratory
for converting juices into a granular or powdered form. The juices were
first concentrated to about 70° Brix. Anhydrous dextrose was then added
until a solid mass resulted from the absorption of water by dextrose to
form hydrated dextrose crystals. From 1 to 2 parts of dextrose to 1 part
by weight of concentrate was usually required, the proportion depending

20 Cruess, W. V., J. H. Irish, and P. H. Eichert. Powdered fruit juices. Pacific Rural
Press 67:741. 1929.

Richert, P. H. Solid grape products. The aim of California investigators. Fruit
Products Journal 9:39-40. 1929.

16 University of California — Experiment Station

upon the amount of water absorbed by the dextrose. It has also been
found possible to add the required amount of dextrose before concen-
tration. The solidified mass was ground to the desired degree of fineness.
It dissolved readily in water and was a satisfactory base for unf ermented
drinks. On prolonged standing, however, the granular or powdered
product tended to "cake" unless stored in airtight containers. It is
believed that such a product would be useful in soda fountains, in the
manufacture of prepared gelatin desserts, and in the home for preparing
refreshing beverages and frozen desserts. It would be convenient for use
by campers, "hikers," and others who require highly concentrated foods.

FRUIT SIRUPS FOR TABLE USE

Acording to statistics of the United States Department of Agriculture,
about 4,000,000 gallons of maple sirup, about 35,000,000 gallons of sor-
ghum sirup, about 20,000,000 gallons of sugar-cane sirup, and about
125,000,000 gallons of blended sirups (imitation maple and others) are
produced annually in the United States. Cruess (cited in footnote 15,
p. 11) estimates cane molasses for cooking purposes at 25-30 million
gallons and corn sirup for table use at 30-35 million gallons a year. The
grand total is about 240,000,000 gallons of sirups for household use
annually.

If all of this were made from fruit of an average of about 15 per cent
sugar content, over 6,000,000 tons of fresh fruit would be required ; if
made from dried fruit of 60 per cent sugar content, about 1,600,000
tons. If only 10 per cent of it were made from fruit, about 600,000 tons
of fresh fruit or about 160,000 tons of dried fruit would be needed.
These estimates are offered to indicate that production of table sirup is
an important industry.

The usual wholesale price of blended sirups is about $1.00 a gallon. A
ton of grapes will yield about 40 to 45 gallons of sirup, and a ton of
raisins about 150 gallons. Yoder21 gives the cost of manufacture of sugar-
cane sirup at 11 cents a gallon. Canning, boxing, transportation, and
selling costs must be added. Consequently, it can be seen that the return
per ton of grapes, raisins, or other fruit would not be very great, and
probably only surplus and cull fruit could be used. Nevertheless, under
present conditions of surplus production of grapes, raisins, apples, and
prunes, table-sirup manufacture might be considered, remembering that
as with all new food products, much time, money, and effort would be
needed to introduce fruit table sirups on the market.

Sirup suitable for table use was prepared from red wine grapes on a

21 Yoder, P. A. Growing sugar cane for syrup. IT. S. Dept. Agr. Farmers' Bui.
1034:1-35.1919.

Cir. 349] Utilization of California Fruits 17

small commercial scale by this station22 from 1919-1925, and was favor-
ably received in sales trials. The bulletin on the subject (Bulletin 321,
cited in footnote 18, p. 12) is out of print; therefore, the method of
manufacture will be briefly outlined. It was as follows : Thoroughly ripe
red wine grapes of the common varieties such as Zinf andel, Carignane,
and Alicante Bouschet were crushed, stemmed, heated to 160° F, and
pressed. The juice was filtered and then concentrated in vacuo to 67°-68°
Brix. The sirup was allowed to stand several weeks to deposit excess
cream of tartar. It was then bottled and pasteurized at 150° F. Re-
enameled type-L tin plate could be made into the usual sirup-can form
and used for the sirup. The color bleaches and corrosion is severe in
plain tin. At concentrations much above 68° Brix, crystallization of
dextrose to give a solid or pasty mass will occur; but at or below 68°
Brix, yeast will usually develop and cause spoilage in time ; hence the
need for pasteurization.

The flavor is much improved if equal amounts of muscat and red wine
grapes are used in preparing the sirup. The sirups are useful not only
on hot cakes and waffles, in such products as jelly rolls and gelatin
desserts, but also* in fruit punches and other drinks.

White-grape sirup may be made in similar manner except the grapes
are pressed without heating and the juice is heated to about 175° F and
cooled before filtration. Use of equal amounts of muscat for flavor and
of other white grapes of neutral flavor, such as Thompson Seedless, is
recommended.

White-grape sirup darkens slowly in storage, but the flavor remains
pleasing. In plain tin it retained its light color for a much longer period
than in glass, in our tests, owing, probably, to the reducing action of
nascent hydrogen evolved from the metal. If desired, part of the acidity
may be neutralized in the juice by heating with a calculated amount of
calcium carbonate, cooling, and filtering. Calcium tartrate is precipi-
tated and may be recovered for use in tartaric acid manufacture.

Fresh grape juice maybe preserved with sulfur dioxide for future use in
sirup making23 and the sulfur dioxide removed during sirup manufacture.

Apple juice and Bartlett pear juice may be converted into cooking
and table sirups by treating with pectinol or other pectic enzyme as
directed by Marshall,24 filtering, and concentrating in a vacuum pan or
in a "boiled cider" concentrator26 in the open to about 70° Brix. Unless

22 Cruess, W. V., and D. S. Glenn. Table syrup from grapes. Fruit Products Journal
9:366-68,383.1930.

28 Cruess, W. V., and E. W. Berg. Kemoval of sulf urous acid from grape syrup. In-
dustrial and Engineering Chemistry 17:849. 1925.

24 Marshall, E. E. The relation of clarifying and sterilizing treatment to sedimenta-
tion of apple juice. Fruit Products Journal 16:328-29, 331. 1937.

18 University of California — Experiment Station

the juice is treated with a pectic enzyme, the sirup is apt to become a
jelly. The apple sirup is useful in making mincemeat and apple butter
as well as on the table. The pear sirup is satisfactory for table use.

Raisins yield a pleasing table sirup. The procedure used in our experi-
ments consisted in stemming, passing the raisins through the saws but
not the seeder section of a raisin seeder in order to puncture the skins,
extracting several times in a diffusion battery with hot water, and then
proceeding as described for white-grape sirup. Muscat raisins should
be used because of their rich flavor.

Dried figs give a sirup of rich flavor when handled as described for
raisins. The figs are coarsely ground or sliced before extraction. Dates
may be crushed and then extracted, although it is very difficult to filter
the date infusion brilliantly clear. In neither case should the final con-
centration exceed 70° Brix, and both sirups should be pasteurized. Fig
sirup is not laxative ; the so-called "fig sirups" used as laxatives contain
an added laxative such as senna or cascara sagrada.

From prunes a fairly satisfactory table sirup can be secured if prunes
of good quality are extracted with water at 175°-180° F and the in-
fusion concentrated in a vacuum pan to 68°-70° Brix. The sirup is much
less viscous if the infusion is treated with a pectic enzyme.

Table sirups may be made also by sweetening with cane sugar, berry
juices previously treated with a pectic enzyme.

Orange juice should be partially neutralized with calcium carbonate,
filtered, decolorized with carbon, and again filtered before concentration.
The sirup tends to darken and develop a "stale orange" flavor.

FRUIT CANDIES

The per-capita consumption of commercially made candy in the
United States was 15.9 pounds in 1939, according to the United States
Department of Commerce. Much candy is also made in the home. If a
total per-capita annual consumption of 20 pounds is assumed, the total
would be about 2,600,000,000 pounds, or about 1,300,000 tons. In other
words, the use of fruits in candy offers an attractive field of develop-
ment. Most of these candies contain no fruit. Our investigations, begun
in 1918, show that fruits can be utilized readily in many kinds of candy.
Fruit candies are of greater dietary value than other candies because of
the vitamins, minerals, and other special food values of the fruits. Also,
they are less "filling," that is, not so rich ; therefore more may be eaten
without discomfort. Figure 4 shows a type made with dried fruit.

The high cost of candied fruits prevents their general use.

25 Anonymous. Keducing cider to boiled cider. Hydraulic Press Mfg. Co. Bui 82:
1-16. 1930.

Cir. 349] Utilization of California Fruits 19

Our experiments have developed inexpensive formulas for the use of
fruits in candies, many of which can be prepared at a cost not above that
of popular candies of the 5-cent bar type. Space will not permit a full
presentation of our results. For formulas and further details see Exten-
sion Circular 10 and journal articles.26

In Latin American countries and in Spain, fruit-jelly candies are very
popular. They are usually packed in rectangular tin boxes with hinged

Fig. 4. — Dried-fruit candies.

tops; often in the form of a loaf about 4 x 6 x 10 inches which is sliced at
the table for serving as a dessert. In Aix en Provence, France, the manu-
facture of fruit-jelly candies is an important industry. These candies are
popular throughout France. The procedure is similar to that in the
formula given in Extension Circular 10.

In Bari, Italy, a large factory, that of Lorenzo La Rocca, was visited
recently, in which are prepared pure-fruit- jelly bars of two sizes, sell-
ing for the equivalent of about 1 to 3 cents each. Demand was reported
to be excellent. Sales trial in Berkeley in 1920 proved that American
consumers also are fond of such candies.

Dried fruits may be used in chocolate fudges, divinity fudges, cara-
mels, marshmallows, nougats, and various other standard candies as well
as in uncooked candies. For formulas see Extension Circular 10.

26 O'Neill, Agnes, and W. V. Cruess. The home preparation of fruit candies. Cali-
fornia Agr. Ext. Cir. 10:1-31. Eevised. 1938.

Cruess, W. V. Fruit candies. Manufacturing Confectioner 11(3) :33-36; (4) :30-34;
(8): 25-29. August, 1931.

Cruess, W. V. Utilization of fruits in the candy industry. Fruit Products Journal
19:164-66,174.1939.

20 University of California- — Experiment Station

PECTIN

At present considerable quantities of dried apple chops, peels, and
cores are used in preparing powdered pectin and pectin sirups; and
waste lemon peels are used in preparing powdered pectin. The powdered
pectins find extensive use in jelly and preserve factories ; and the pectin
sirups in making jellies and preserves in the home. Some pectin is used
as a medicine in the treatment of diarrhea. For an outline of the pro-
cedures used in preparing pectins commercially see Commercial Fruit
and Vegetable Products (cited in footnote 15, p. 11) as well as the refer-
ences listed therein, and other references given below.27

Expansion of the market for pectin appears to depend upon the dis-
covery and development of new uses for it, both in foods and for in-
dustrial purposes. The California Fruit Growers' Exchange research
staff and others are making progress in that direction.

BASES FOR JELLIES AND JAMS

Jelly Juices. — In 1921-1923 and subsequently, considerable experi-
mental work was done in this station on the preparation, preservation,
and utilization of fruit juices to be used in jelly making.28

In brief, the recommended procedure consists in cooking crushed or
sliced fresh fruits of suitable variety with water to cover, until soft;
pressing ; filtering the juice and concentrating it, preferably in a vacuum,
until it will give a good jelly if it is boiled to the jellying point with an
equal volume of cane sugar. The unsweetened juices are preserved by
pasteurization ; namely, by heating to 180°-212° F, canning or bottling
scalding hot, placing containers on sides to sterilize caps or lids, and
cooling. Re-enameled type-L or similar cans or glass containers must be
used for red juices.

To use the juice the housewife or manufacturer adds sugar in equal
amount and cooks to the jellying point, normally about 8° F above the

27 Wilson, C. P. Kelation of chemistry to the citrus products industry. Industrial
and Engineering Chemistry 20:1302-7. 1928.

Wilson, C. P. The manufacture of pectin. Industrial and Engineering Chemistry
17:1065-68.1925.

Wilson, C. P., et al. U. S. Patent No. 1,497,884. U. S. Patent Office, Washington,
D. C. June, 1924. (In using patented processes, permission must be obtained from
the holders of the patents.)

Booker, W. A. Fruit pectin: its commercial preparation and uses, vi + 170 p. Avi
Publishing Co., Inc., New York, N. Y. 1928.

28 Cruess, W. V., and L. Singh. Marmalade juice and jelly juice from citrus fruits.
California Agr. Exp. Sta. Cir. 243:1-8. 1922. (Out of print.)

Cruess, W. V., and G. L. Marsh. Fruit jelly juices. Fruit Products Journal 11:
325-27. 1932. (Out of print.)

Cruess, W. V. Utilization of surplus plums. California Agr. Exp. Sta. Bui. 400:
1-21. 1926. (Out of print.)

Cir. 349] Utilization of California Fruits 21

boiling point of water — 220° at sea level. The jelly maker is saved the
trouble and labor of preparing the raw fruit and may make jelly at any
time of the year. Many jelly manufacturers preserve such jelly juices
for their own use ; but so far as we know, such juices are not on the retail
market for household use. Our sales trials indicate a latent demand for
these products for home use. Any one who may wish to undertake their
manufacture should make certain that no patents are infringed.

In Spain, the Seville (sour) orange is converted into a canned marma-
lade base and exported to England and elsewhere for use in the com-
mercial preparation of marmalade. Cruess and Singh (cited in footnote
28) developed a satisfactory procedure for preparing and canning a
marmalade juice from California oranges and lemons.

Jam Bases. — We have packed and sterilized in cans undiluted purees
of peaches, apricots, plums, and pears. These were found suitable for
preparing fruit jams and butters in the home or factory by adding an
equal weight or volume of sugar and cooking to the desired consistency.

Also the sliced, crushed, or coarsely ground fruits previously prepared
as for canning in sirup, were steamed, packed hot in cans, sealed, pro-
cessed in boiling water, and cooled. For household use in jam making,
such a pack is probably preferable to the puree.

Plum and apricot jam bases were kept in plain tin cans for over three
years without loss from corrosion.

FROZEN PACK

This station29 was among the first to undertake an investigation on
the freezing storage of fruits in small containers for retail distribution,
although the barreling of berries and some other fruits for use in pre-
serve factories had been done commercially previous to our studies. In
recent years interest and research in frozen pack have greatly increased,
and the litertaure now is extensive. Only a few of the leading references
will be cited ; for additional lists see Tressler and Evers30 or Cruess (foot-
note 15, p. 11). Several other references31 may also be consulted.

Owing to the fact that the principles and details of preparing, packag-

29 Cruess, W. V., and E. L. Overholser. Freezing fresh fruits in cans. Canning Age.
6:97-99. 1925.

30 Tressler, D. K., and C. F. Evers. The freezing preservation of fruits, fruit juices
and vegetables, x -f 369 p. Avi Publishing Co., Inc., New York, N. Y. 1936.

31 Diehl, H. C, W. T. Pentzer, J. A. Berry, and C. E. Asbury. Suggestions for freez-
ing foods are outlined. Western Canner and Packer 26(5):31-33; (6):39-41;
(7) :33-35; (8) :43-44. 1934.

Joslyn, M. A. Preservation of fruits and vegetables by freezing storage. Cali-
fornia Agr. Exp. Sta. Cir. 320:1-35. 1930. (Out of print.)

Joslyn, M. A., and G. L. Marsh. Changes occurring during freezing storage and
thawing of fruits and vegetables. California Agr. Exp. Sta. Bui. 551:1-40. 1933.
(Out of print.)

22 University of California — Experiment Station

ing, freezing, storing, and distributing frozen-pack fruits are well cov-
ered in the publications cited, these processes will not be presented here
except in outline.

Well-ripened fruits of suitable varieties are prepared as for canning.
They are then packed with a suitable amount of dry sugar or suitable
sirup in cartons or cans and frozen quickly by some system that will
promote rapid exchange of heat between the fruit and the freezing
medium. They are stored at a low temperature, preferably about 0° F,
and distributed under freezing refrigeration to consumers.

The consumer usually thaws the fruit before serving, although it
may also be served in the frozen state.

Sweetened purees may be frozen in cans or cartons for use as frozen
desserts.

Apricots, peaches, pears, and apples tend to become brown and off-
flavored if not parboiled, or frozen in sirup. Sirup, however, adds greatly
to the weight of the packed product. Marsh and Joslyn, and also Wood-
ruff,32 find that dipping of the cut fruits in dilute sulfur dioxide, salt,
phosphoric acid, or citric acid solutions before freezing prevents darken-
ing and minimizes undesirable oxidative changes in flavor.

Citrus juices and other juices retain their fresh flavor very well in
the frozen state when packed under exclusion of air.

Frozen fruits have been well received, and the principal obstacles to
a more rapid increase in their use is the scarcity of retailers' freezing-
storage facilities, and the rather high retail cost of the products.

FRUITS IN ICE CREAMS AND ICES

While considerable fruit is used at present in ice creams and ices, often
so little is added that reinforcing with artificial color and flavor is neces-
sary. Investigations conducted by the divisions of Fruit Products and
Dairy Industry of this station33 have demonstrated that the addition
of artificial color and flavor is unnecessary if sufficient fruit is used;
and that the frozen products are greatly improved by use of a larger
proportion of fruits than is customary.

Since the subject is well covered in Circular 331, the presentation here
will deal only with subjects not found in the circular.

Special Packs of Canned Fruits. — We have packed, experimentally,

32 Marsh, George, and M. A. Joslyn. Unpublished data.

Woodruff, J. G. Preserving fruits by freezing. I. Peaches. Georgia Agr. Exp. Sta.
Bui. 163:1-46. 1931.

33 Turnbow, G. D., and W. V. Cruess. Investigations on the use of fruits in ice cream
and ices. California Agr. Exp. Sta. Bui. 434:1-38. 1927. (Out of print.)

Cruess, W. V., W. C. Cole, and M. A. Joslyn. Fruits in ice cream and ices. Cali-
fornia Agr. Exp. Sta. Cir. 331:1-28. 1933.

Cm. 349] Utilization of California Fruits 23

apricots prepared for use in ice cream as follows : Thoroughly ripe apri-
cots were pitted, ground, sweetened with 20 per cent of sugar (2 pounds
to 8), heated to boiling, canned boiling hot, sealed, and processed a short
time in boiling water. One no. 10 can of this fruit would be used with
enough basic ice-cream mix to give 5 gallons of fruit-ice-cream mix, or
about 10 gallons of finished ice cream. In using such generous amounts
of fruit, care must be taken that the finished product is above the food-
law minimum in fat content.

Similar products were made wTith peaches and pears. The pear flavor
carries very well in both water ice and ice cream — is, in fact, superior to
the peach in that respect.

In some cases the diced fruits are desirable. In figure 5 is illustrated
equipment for dicing fruits to be canned as fruit cocktail, a product
useful in"tutti frutti" ice cream.

Use of Avocados. — Use of avocados in ice cream and experiments on
other avocado products have been reported by Cruess and Harold.31 We
have found that the ground, lightly sweetened pulp may be preserved
indefinitely in the frozen state and is equal to the fresh for use in ice
cream. Preservation by heat destroys the fresh flavor and renders the
fruit unfit for use in ice cream. The frozen-pack fruit could be prepared
by shippers or others in southern California from sound, off-grade fruit
and distributed to the ice-cream industry.

Prunes in Ice Cream. — Dried prunes of the French variety gave, in
our experiments, ice creams and ices not only of very pleasing flavor,
but also with the mildly laxative properties of that fruit. The fruit is
cooked and sieved and the resulting puree added to the basic mix. For
the convenience of ice-cream makers, the puree of "sieved prunes" may
be canned very easily. See Bulletin 483 of this station.35 See Circular
331 (footnote 33, p. 22) for further details. Fresh prunes may be pitted
by the machine shown in figure 6 and ground for use in ice cream.

Other Fruits and Products in Ice Creams and Ices. — Purees, pulps,
and sauces made of nectarines, plums, fresh prunes, cherries, and apples
have proved to be satisfactory flavor bases for ice creams and ices. Mixed
fruits such as commercially canned fruit cocktail, fruits for salad, mixed
frozen pack, or mixed fresh fruits give very pleasing ice creams and
ices. The mixed fruits should be chopped, diced, or coarsely ground.
Certain blends of fruit juices such as red grape, orange, and berry are
particularly well suited for the preparation of ices.

34 Cruess, W. V., and E. Harold. Investigations on utilization of cull avocadoes.
Fruit Products Journal 7(6) :12-14, 20. 1927.

35 Mrak, E. M., and W. V. Cruess. Utilization of surplus prunes. California Agr.
Exp. Sta. Bui. 483:1-34. 1929.

24

University of California — Experiment Station

Fig. 5 — Improved fruit dicer: A, closed; B, open. (Courtesy of
Food Machinery Corporation.)

Cir. 349]

Utilization of California Fruits

25

Joslyn and Cole36 report as follows on the results of experiments on
the use of wines in ice creams and ices : Claret and Riesling dry wines
gave ices of pleasing flavor and good texture, and the ices have possibili-
ties for desserts or as side dishes for meats. The following formula was
satisfactory: wine, 25 per cent; cane sugar, 17 per cent; corn sugar, 5
per cent ; acidity, 0.5 per cent total acid expressed as citric ; pectin, 0.5
per cent; the remainder consists of regular basic ice mix. Muscatel,

Fig. 6. — Fresh-fruit pitting machine. (Courtesy of Elliott Machinery Company.)

sherry, and port did not give ices of satisfactory flavor. None of the
wines were satisfactory in ice cream. Prospective users of wine in ices
or ice creams are warned that they must secure approval of state and
federal liquor-control authorities. Penalties for violating regulations
are very severe.

Fruits Canned for Use in Homemade Ice Creams. — In experiments
conducted in this station, various fruits have been canned for making

36 Joslyn, M. A., and W. C. Cole. The use of wines in ices. Wines and Vines 18(8) :8.
1937.

26 University of California — Experiment Station

ice creams and ices in the home. Figs, apricots, freestone peaches, and
pears are particularly satisfactory. The ripe fruit is prepared as for
canning in sirup as halves. It is then coarsely ground, mixed with 1 part
of sugar to 4 of fruit, heated to boiling, canned hot, sealed, processed in
boiling water until well cooked; and the cans are then thoroughly cooled.
The product is somewhat better for use in home recipes if, before can-
ning, a stabilizer is added, such as fruit pectin previously dissolved in
sugar and water, or alginate, or gelatin.

If the fruit is whipped with an egg beater before placing in the freez-
ing tray of the home refrigerator, and again as it begins to harden, the
finished product is "fluffy" and not too dense. Or it may be added to an
ice-cream mix or to a fruit-ice mix, recipes for which are available from
dealers in home refrigerators.

Frozen Fruits. — The usual fruit ice or sherbet contains relatively
little fruit. It is chiefly basic mix consisting of fruit acid, sugar, stabil-
izer, water, and added flavor or color, or both. Some fruit, usually 10 to
25 per cent, is added to this basic mix.

Frozen-pack fruits prepared and canned as outlined in the preceding
section or prepared in similar manner from the fresh fruits give on
freezing in a commercial freezer a healthful and pleasing all-fruit
dessert. But, if the fresh fruit is used, it should be sieved to a fine con-
sistency to avoid lumps ; or should be cooked with the sugar until soft.
Berries, apricots, freestone peaches, nectarines, and pears respond well

to this procedure.

DRIED-FRUIT PRODUCTS

As a result of the investigations of Christie, Nichols, Mrak, and others
of the Fruit Products Division, in part in cooperation with the divisions
of Agricultural Engineering and Pomology of this station and other
agencies, important improvements have been made in the drying of
fruits and in the processing and packing of dried fruits. Examples are
improvements in prune-dehydration practice and in prune-dehydrater
design, walnut-dehydration practice and dehydrater design, dehydra-
tion of grapes, and the development of a satisfactory procedure for pre-
paring and dehydrating a new product, dried cling peaches.

Dehydration affords a means of improving the quality of dried prunes
and some other fruits, because it prevents fermentation and minimizes
enzymic changes such as darkening of the flesh and deterioration of
flavor during drying. See Bulletin 40437 for further information.

Canned Prunes. — A satisfactory procedure is described in Bulletin
483 (cited in footnote 35, p. 23) for the canning of ready-to-serve prunes

37 Christie, A. W. The dehydration of prunes. California Agr. Exp. Sta. Bui. 404:
1-32. Revised 1929 by P. F. Nichols. (Out of Print.)

Cir. 349] Utilization of California Fruits 27

in light sirup. Thorough blanching before canning, acidification of the
sirup, use of a deep head space, and of resistant type-L or similar tin
plate are recommended. When so canned the fruit keeps well without
serious corrosion of the plate.

We believe that canned or glass-packed, processed dried prunes of
high moisture content, 30-33 per cent, packed without added liquid in
a form similar to that of several products now on the market, would find
considerably greater favor if extensively advertised. They are very suit-
able for eating out of hand and appeal to children particularly. The
product keeps well, does not dry out in the sealed container and as long
as the can is sealed, is immune to insect attack, molding, sugaring, and
fermentation. Similarly, dried figs, peaches, dates, and pears may be
packed in glass for eating out of hand.

Dry-Packed Canned Dried Figs and Raisins. — Dried figs and muscat
raisins responded well to processing and packing in a manner similar to
that used for dry-pack prunes. Sulfur ed dried fruits kept well in glass
containers when packed in the above manner, but attacked the tin plate
with formation of hydrogen sulfide gas when canned ; also they darkened
rather rapidly in the cans.

Such fruits cook quickly when taken from the container and heated
in water or light sirup, so that preliminary soaking in water is un-
necessary.

Improved Nonmetallic Packages. — Recently, transparent cellophane
wrappings or bags of "Pliofilm" and other nearly moistureproof mate-
rials have been made available as moisture-retaining linings or wrap-
ping for cartons. Also paper "cans" lined with a moisture-resistant
material and sealed with tin ends have been perfected by one of the
large can companies. Preliminary tests indicate that these packages are
very resistant to diffusion of moisture. In other words, inexpensive
packages of the "Pliofilm"-hmer-liner and paper-"can" types greatly
prolong the shelf life of dried fruits and deliver them in a moister, more
attractive condition to the consumer.

Sugaring of Dried Fruits. — Investigations by Christie, Nichols,
Mrak, and others of this laboratory, and by Hiltner of the California
Dried Fruit Association demonstrated that sugaring of carton-packed
prunes could be prevented by coating with a thin film of oil, as was done
later commercially with raisins. An edible vegetable oil must be used
because edible mineral oils are considered medicines by the food-and-
drug authorities. Edible vegetable oils rancidify in time, although when
accompanied by a natural anti-oxidant such as Avenex, rancidity is
delayed. Also it was found by Cruess and Katzprowsky (unpublished

28 University of California — Experiment Station

data) that coating of prunes and other dried fruits with a dilute solution
of dextrin, pectin, gelatin, or other suitable food colloid delays sugaring
and improves the appearance of the fruit.

Pitted Prunes. — Machines are now available for pitting fresh prunes.
When dehydrated after pitting, the product is attractive in appearance
and flavor, particularly if steamed or lightly treated with sulfur dioxide
fumes to inactivate enzymes before drying. Dried prunes are pitted
commercially for bakers' use; the improved, modern machines do very
satisfactory work and leave practically no broken pits. The pitted dried
prunes may be finely ground, as are figs, for paste; the paste is then
brought to 35-40 per cent moisture, canned, and sealed scalding hot for
bakers, candy makers, ice-cream makers, restaurant, and household use.
If packed at the usual dried-prune moisture content of 20-25 per cent,
the paste is too dense and tough to be easily used. See sections on fruit
candies (p. 18) and fruit ice creams (p. 22) for methods of using prune
paste or pulp in these products. The machine illustrated in figure 7 is
useful for pitting dried prunes and dates.

Mrak found that prune pulp and paste can be used successfully in
stuffed crackers, that is fruit "newtons," if cooked with a considerable
proportion of invert sirup. If the customary corn sirup (glucose) is
used, the filling rapidly dries out, and toughens after baking.

See section on cereal products (p. 31) for further suggestions.

Prunes have been shown by Morgan, Hunt, and Squier38 to be very
rich in vitamin G (riboflavin) and rich in A, both very important in
human nutrition.

Apricots and Peaches. — In normal times the European markets take
a large proportion of the dried-fruit output, including apricots and
peaches. With the abundance and relatively low prices of fresh and
canned fruits, as well as their convenience, it is difficult to increase
American consumer interest in dried fruits.

Nevertheless, dried apricots and peaches are both excellent sources
of vitamin A ; are rich in basic mineral elements, that is, those that com-
bat "dietary acidosis"; and have been shown by Whipple30 to be very
rich in the substances that promote hemoglobin formation. That is, they
are valuable in combatting anemia, such as that following severe loss of
blood, or after debilitating diseases such as influenza and pneumonia.
If these facts were made known more generally, they should greatly
stimulate the use of these fruits.

38 Morgan, A. F., M. J. Hunt, and M. Squier. The vitamin B and G content of
prunes. Journal of Nutrition 9:395-402. 1935.

89 Whipple, G. H. Hemoglobin formation as affected by diet and other factors.
American Medical Association Journal 104:791-93. 1935.

Cm. 349] Utilization of California Fruits 29

Processing the dried fruits in dilute sirup improves their appearance
and their edibility as a candy or between-meal "snack."

When ground to a paste, they are useful in bakery products, "new-
tons," and for rapid cooking into sauces and jams.

Fig. 7. — Small dried-fruit pitter (upper) and dried-
fruit grinder (lower), for preparing date paste and
similar products. (Courtesy of Elliott Machinery Com-
pany.)

A factory in Oakland, California, dehydrates dried apricots, peaches,
and pitted prunes to a bone-dry (nearly water-free) state, grinds them
to a powder or coarse meal, and packs them in friction-top cans. They
are used by bakeries, and to some extent by others. They are excellent
for use in bread.

The dehydration of clingstone peaches was first done commercially
by Christie and Cruess at the University Farm, Davis, in 1919 (see

30 University of California — Experiment Station

Bulletin 404, cited in footnote 37, p. 26). The procedure developed by
them is now in commercial use for drying 35,000 to 50,000 tons (fresh
basis) of clingstone peaches annually. The fruit is pitted by machine,
lye-peeled, sulf ured on wooden slat trays, dehydrated, binned to equalize
the moisture, graded, sorted, and packed in boxes, cartons, or cellophane-
wrapped packages. The product was popular in Holland, Denmark, Nor-
way, and Sweden, before the war.

See Commercial Fruit and Vegetable Products (cited in footnote 15,
p. 11) for information on standard methods of drying fruits and on
processing and packing dried fruits. The Station has in preparation
a circular by Mrak and Long on fruit drying and dried-fruit packing.39-1

Figs. — At present the bulk of the dried-fig pack is converted into a
heavy paste made by finely grinding sorted, selected figs. The paste is
packed in paraffin-paper-lined boxes for use by the baking and confec-
tionery industries. Fig paste has long been a standard commercial
product, and the Station claims no credit for its development. This
laboratory has, however, developed formulas for its use in candies, in
a breakfast cereal, and in ice cream. See sections on use of fruits in
these products.

Also, experiments have been conducted in this laboratory on the
utilization of the lower grades in preparing fruit wines, and of cull figs
in the manufacture of brandy. Some figs are used commercially in brandy
manufacture, but like other fruit brandies, fig brandy is not in great
demand because of the abundance of better-known distilled liquors.

In localities where figs do not dry well in the sun, the unpublished
data of Christie and of Nichols show that dehydration may be used
advantageously. Such figs are satisfactory for making into paste. Sulfur-
ing is advisable if a light color is desired. The freshly sulfured fruit
should be exposed to the sun for a few hours before dehydration in
order to improve the color.

Cherries. — In 1920-1923 Christie and Cruess40 conducted experiments
on the drying of cherries and cooperated with commercial dehydrators
in drying this fruit. A satisfactory procedure consisted in dipping the
fruit a few seconds in dilute (0.5 per cent) sodium hydroxide, rinsing,
spreading on wooden slat trays, sulf uring about % to 1 hour in the fumes
of burning sulfur, and dehydrating at not above 150° F in a tunnel
dehydrater.

39a Mrak, E. M., and J. D. Long. Methods and equipment for the sun-drying of
fruits. California Agr. Exp. Sta. Cir 350. (In press.)

40 Cruess, W. V., and A. W. Christie. Dehydration of fruits. California Agr. Exp.
Sta. Bui. 330:1-30. 1921. (Out of print.)

Cruess, W. V., and A. W. Christie. Some factors of dehydration efficiency. Cali-
fornia Agr. Exp. Sta. Bui. 337:1-23. 1921. (Out of print.)

Cir. 349] Utilization of California Fruits 31

The fruit "refreshes" well on soaking in water a few hours and cook-
ing. Unless cherries are sulfurecl before drying, the color of black
varieties becomes brown, and that of white ones darkens badly.

Pears. — The usual sun-dried pear is attractive in appearance but of
rather poor flavor owing to its high sulfur dioxide content. Cruess and
Christie (cited in footnote 40) found that pears prepared by halving,
lye-peeling, exposing a relatively short time to sulfur dioxide fumes, and
dehydrating at not above 150° F gave products of attractive appearance
and excellent cooking quality. With modern mechanical peelers, it is.
possible that the price could be materially reduced and the quality
improved.

Apples. — The drying of apples is a declining industry at present,
although the present commercial product is satisfactory. Improvement
in cold-storage practice has made fresh apples available throughout the
year, and the export market is less extensive than formerly.

It is possible that "apple flakes," a confectionlike, sweetened, dried-
apple pulp developed at the Utah Agricultural Experiment Station" in
1921, or a similar product devised more recently at the Washington
Agricultural Experiment Station,42 might be worthy of commercial trial.
These products cook quickly and have been reported to possess a pro-
nounced apple flavor. They may be used as confections or for cooking.

We believe, however, that other apple products, such as canned juice,
canned sauce, and peeled, sliced apples, fresh or frozen, for bakers' use,
have greater possibilities.

FRUITS IN CEREAL PRODUCTS

Man's most important source of energy is that of the cereal products,
including bread, cakes, crackers, breakfast cereals, hot cakes, pies, and
waffles. Some of these, such as pies, raisin bread, tarts, newtons, and
Jelly rolls, contain fruits or fruit products. In England various tea
cakes contain a great quantity of raisins and other fruits, and scones and
buns are made with raisins or currants.

In Bread. — Raisin bread was established commercially many years
ago by an intensive advertising and sales-service campaign by the then
newly formed raisin growers' association. The new bread proved popular
and utilized many thousands of tons of raisins. The early raisin breads
were rich in raisins and therefore attractive in appearance and of dis-
tinctive and pleasing flavor. In a survey conducted in 1931 by J. H.

41 Abell, T. H. Apple candy: a commercial use for cull apples. Utah Agr. Exp. Sta.
Bui. 179:1-14. 1921.

42 Gerritz, H. W., and J. L. St. John. Concentrated fruit and vegetable products :
a new apple concentrate. Food Industries 11:369-70, 416-17. 1939.

32

University of California — Experiment Station

Irish and W. V. Cruess,43 it was found that most raisin breads then on
the market were decidedly deficient in raisins ; most contained less than
10 per cent by weight of raisins and some less than 5 per cent. The best
raisin breads contained over 30 per cent of raisins. Figure 8 shows the
appearance of two raisin breads from the survey.

While loaves made with very high content of raisins are not so light
in texture nor of such large volume as the usual raisin loaf, they are
much superior in flavor and in appearance of the cut slice. They retain
their freshness for a long period owing to the invert sugar of the fruit,
and are particularly desirable for toasting. We have no suggestions for

-Samples from raisin-bread survey ; on the left, satisfactory
raisin content.

improving existing raisin breads and promoting the use of raisins in
bread, other than cooperation of the raisin packers and distributors
with bakers to increase the raisin content of commercial raisin breads
to above 30 per cent. At present low prices, this would not add materially
to the cost of the loaf. It would greatly improve quality and should
correspondingly increase the use and markets for raisins. We would sug-
gest that a few leading bakeries in each large urban area be induced to
place such a bread on the market; if their venture proves profitable,
other bakers will follow suit.

In England, currant buns and raisin scones are very popular. The
bun contains a generous amount of Greek or Australian currant raisins
(dried Zante currant grapes). We have similar products in America.
The raisin scone, however, is not generally known in America. As served
in restaurants and tea parlors in England, it appears to be made of
baking-powder biscuit dough, to which is added seedless raisins, perhaps
25 per cent by weight. It is the English equivalent of the great American

43 Irish, J. H., and W. V. Cruess. Eaisin bread investigations. Bakers Weekly 71(6) :
45^7. 1931.

Cir. 349] Utilization of California Fruits 33

doughnut, and is served with tea, Bovril, English "coffee," or other hot
drinks, much as Americans serve coffee and doughnuts. It might prove
popular in America if properly introduced by chain restaurants, cafe-
terias, and bakeries.

In 1929 Mrak and Cruess reported successful experiments made in
cooperation with the Sperry Flour Company of San Francisco, and
several bakeries in the Oakland-Berkeley area in making prune bread.
Subsequently, in cooperation with L. B. Williams of the Dried Fruit
Research Institute of San Francisco, one of the large chain-store organi-
zations baked prune bread made according to the Station formula,
and sold it one day a week ("prune-bread day"). Demand was excellent.
Prune pulp made by sieving cooked prunes was added to the dough. The
formula will be found in Bulletin 483 (cited in footnote 35, p. 23) but
is subject to revision to suit the bakery routine.

Pitted, chopped prunes, if free of pieces of pit, may be incorporated
in bread dough; also vacuum-dehydrated, bone-dry, powdered prunes
may be so used, but are much more costly than the pulp or pitted prunes.
Canners could supply canned prune pulp in no. 10 cans at low cost for
use in prune bread ; or bakers could prepare the pulp readily by cooking
and sieving the dried prunes.

At one time figs were used in a bread. The figs were torn open by
machinery, sorted on a belt, cut into pieces about % to *4 inch in di-
ameter and dusted with flour for sale to bakers. The bread was pleasing
in appearance and flavor. It enjoyed a limited sale in California some
twenty years ago. If supported by sustained sales and service effort, it
might be made an important market for figs.

Apple bread has been made at various times. Apple puree, or un-
sweetened applesauce, or finely ground dried apples may be added to
the dough. Owing to the light color of the apples, they are not very evi-
dent to the eye. The loaf is said to remain fresh for a considerably longer
time than plain bread, and it toasts well.

In general, the less-acid fruits, such as raisins, prunes, and figs, appear
better suited than the tart fruits, such as apricots, peaches, and apples,
for use in bread.

Newtons. — Fig newtons, sweet pastry cookies stuffed with fig paste,
are well known, low-priced, and popular. Ground figs (fig paste) are
cooked to a heavy consistency with sugar and glucose or invert sirup
and the paste is folded into the rolled-out newton dough; the dough is
then cut to the desired length and baked in a continuous oven.

Prune pulp, apricot pulp, and other fruit pulps can be used in a
similar manner. We found that prune pulp in newtons dried out rather

34 University of California — Experiment Station

rapidly, and the newtons became soggy. If used within a few days after
baking, they were satisfactory.

Fruit Products for Use in Pies. — With muscat raisins a rich and
pleasing pie is obtained; with Thompson Seedless raisins the pie is
rather characterless.

Canned water-pack Thompson Seedless grapes picked before they are
fully ripe are a very good substitute for gooseberries in pies. Canned
muscat grapes are used to some extent in pies.

Sieved prunes make an excellent open or crisscross pie of the pumpkin
type. Bakers have found the formula given in Bulletin 483 (cited in
footnote 35, p. 23) satisfactory.

We believe that the greatest possibility for increasing the use of
fruits in pies is not in the commercial pie industry, but in the home —
namely, in providing the housewife with canned fruits suitable for use
in pies and at low cost. No one at present packs solid-pack, canned fruits
for pie, in cans of suitable size for home use. The housewife must use
fresh fruits in season, or dried fruits or relatively high-priced canned
fruits in sirup. The customary no. 10 ("gallon") size can of pie fruit
is packed for wholesale distribution to commercial bakers and is much
too large for home use. A no. 2% can is about the proper size for the home.

We have canned peaches sliced crosswise, not in the usual commercial
crescent-shaped slices, solid-pack, and found them well received by
Berkeley housewives. Slices of this type give a homemade appearance
to the pie. The sliced fruit was steamed until partially cooked, canned
hot, sealed, and processed a short time in boiling water. The fruit packed
in this manner was preferred to that thickened with flour or tapioca
starch and flavored with cinnamon and sugar. The housewives who coop-
erated in the experiments preferred to add their own thickening agent
and flavoring.

Pears were packed successfully in similar fashion. A small amount of
boiling water was added to fill the spaces.

Ripe, halved apricots were steamed and packed as outlined for the
sliced peaches.

Prune pulp was canned and used in open pies. Fresh plums were
canned whole as solid pack after steaming until soft.

Pitted, sour, water-pack, pie cherries are already available for home
use. The Royal Anne (Napoleon) and Black Tartarian, the principal
California varieties, are not much in favor for use in pie. Some Royal
Amies have been pitted, artificially colored, and canned for use in pies.
This is an expedient of doubtful value.

Of the other California fruits, the fig is one of the most satisfactory
for use in pie. The fruit may be sorted ; the softer fruit set aside for pie

Cir. 349J Utilization of California Fruits 35

use, washed, steamed thoroughly, canned in solid-pack scalding hot,
sealed, and processed about 1% hours in boiling water in no. 2x/2 cans
or 2 hours in no. 10 cans. The housewife or baker adds sugar, thickener
if needed, and uses the product in either open or covered pies. The varie-
ties with prominent seeds such as the Calimyrna are preferred.

Bakers find frozen-pack fruits excellent for use in pies. Bulk-packed
berries and pitted sour cherries, in particular, are so used in important
amounts. Perhaps a market could be developed for small packages of
frozen-pack berries for use in homemade pies. For this purpose they
could be packed in cartons or paraffined cups as a 5:1 pack instead of
the usual 2 or 3 : 1. Price is, of course, an obstacle in this instance.

Apricots and peaches for bakers' use should be dipped in dilute sulfur
dioxide solution before freezing in order to prevent darkening.

Pears in any form have not proved popular for use in pies. In most
canneries the pie grade of pears are ground and run into the sewer as a
waste product.

Water-pack and solid-pack canned fruits in no. 2% cans for house-
hold use are not only useful in pies but also in preparing jams, pre-
serves, butters, and jellies.

Prepared Fresh Fruits for Bakers' Use. — At one time commercial pie
bakeries used chiefly canned apples or fresh apples prepared on the
premises for use in pies. At present much of the bakers' needs for pie
apples is supplied by sliced fresh apples prepared in factories devoted
to their production. As the publication on this subject by Mrak and
Joslyn44 is not readily available, the following details are given.

1. A sodium bisulfite solution testing about 3,000 to 4,000 p. p.m. sulfur
dioxide is prepared by adding about 1% pounds of C. P. sodium bisulfite
to 20 gallons of water. A sulfur dioxide solution of about 4,000 p. p.m.
can also be used. Two per cent salt may also be added if desired.

2. Paraffined wood, aluminum, stainless steel, or block-tinned equip-
ment should be used for handling the solutions and fruit. Iron and
copper must be avoided.

3. The apples are peeled, cored, and discharged into the solution. They
are then removed, sorted, and trimmed, sliced or quartered, and dis-
charged into the fresh solution.

4. The prepared fruit is exposed to the fresh solution for not less than
2 nor over 5 minutes. As the solution becomes weaker, the length of treat-
ment is increased.

44 Mrak, E. M., and M. A. Joslyn. Investigations on the use of sulfurous acid and
sulfites in the preparation of fresh fruits and frozen fruits for bakers' use. Fruit
Products Journal 12:135-40. 1933.

36 University of California — Experiment Station

5. The solution is kept up to strength by adding more sulfur dioxide
or bisulfite as necessary and occasionally replacing the solution with a
freshly prepared one. The strength of the solution can be checked and
controlled by frequent titration with standard iodine. This is not neces-
sary unless rigid control is essential. Details of this testing procedure
will be sent upon request.

6. The treated fruit is drained and packed in paraffin-paper-lined
boxes. It should be delivered to bakers and other users promptly.

Peaches, pears, and apricots may be handled in similar manner.

Fruit Breakfast Cereals. — H. M. Reed, formerly of this laboratory,
reported in 192945 on a successful formula for a dried-fruit cereal. Since
his paper is not easily available, the more important details will be given
briefly.

The formula for preparation of one such product is as follows :

7*4 pounds whole-wheat flour
14% pounds white flour

1 pound baking powder

1 pound salt

21/£ pounds nonrancidifying solid fat
721/2 pounds prune pulp of about 73 per cent moisture

The ingredients were mixed into a dough ; quickly formed into small
loaves; placed in bread pans greased with a nonrancidifying fat; baked
in a slow oven at about 410° F to avoid scorching and to cook through.
The loaves were then sliced and the slices dried bone-dry on trays in a
dehydrater. These were then coarsely crushed, screened to uniform size
like Grapenuts, toasted a short time at 300 °, and packed in parchment-
lined, paraffin-wrapped cartons. The product resembles Grapenuts in
color and appearance and has a pronounced prune flavor. It is served in
the same manner as any dry cereal.

Cruess and Irish46 reported that the following formula gave a product
that is not so hard and dense as that given by the Reed formula :

3 00 parts finely ground dried fruit
100 parts Cerelose or other corn sugar
50 parts wheat bran
100 parts whole-wheat flour

3 parts salt

4 parts baking powder.

All ingredients except the baking powder were mixed with water to
give the desired consistency. Then the baking powder was mixed in

45 Reed, H. M. A new fruit cereal. Fruit Products Journal 8(10) :7-9. 1929.

46 Cruess, W. V., and J. H. Irish. The use of fruits in cereals. Fruit Products Journal
12:302-3. 1933.

Cm. 349] Utilization of California Fruits 37

quickly and the dough formed into loaves. These were dusted with whole-
wheat flour ; placed in pans greased with nonrancidif ying fat and baked
at about 410° F. The loaves were then sliced and treated as described in
the Reed procedure.

A third procedure described by Cruess and Irish was as follows :

100 parts wholewheat flour
100 parts ground dried fruit
25-50 parts bran

6 parts baking powder
3 parts salt
Water to make a stiff dough

The dough was rolled on a slab or smooth board surface to about y32
inch in thickness and dusted with flour. The thin sheet of dough was
quickly cut into small rectangular pieces of about the size of Post
Toasties and baked in a quick oven to a golden brown. The baking
powder raises the "flakes" somewhat and makes them rather crumbly in
texture. This product would probably lend itself well to continuous and
automatic factory procedure.

Attempts were also made to prepare flakes by dropping a thin batter
of fruit pulp, flour, baking power, and other ingredients on a hot metal
surface but without very marked success. Sticking and scorching were
the main difficulties. Possibly these could be overcome with commercial-
scale equipment. At present, date flakes are made commercially in Beau-
mont in Riverside County by drying a thin layer of date paste on a

hot roll.

FRUIT SAUCES

At the present time, applesauce is the only canned fruit sauce avail-
able to the housewife and to eating establishments. Our experiments
have demonstrated that excellent canned and glass-packed sauces can
be made from other fruits.47

The procedure recommended for apricots, pears, and peaches is as
follows : The fruits are prepared as for canning as halves, then ground
coarsely. One part of sugar is added to about 6 of fruit. The fruit is then
heated to boiling, canned, sealed hot, processed a short time at 212° F,
and cooled thoroughly. If the product is overcooked or cooled insuffi-

47 Cruess, W. V. Utilization of surplus peaches and pears. Canning Age 12:457-64,
512-15. 1931.

Marsh, G. L., and W. V. Cruess. Experiments on the utilization of surplus apri-
cots. Fruit Products Journal 11:334-35. 1932.

Cruess, W. V. Canned crushed peaches. Fruit Products Journal 15:328. 1936.

Cruess, W. V. The utilization of surplus plums. Fruit Products Journal 18:72-74,
89, 91, 101-5. 1938.

Cruess, W. V. Commercial fig products. Fruit Products Journal 17:337-39, 343,
368, 369, 377; 1937; 18:39-42. 1938.

38 University of California — Experiment Station

cieiitly, it is apt to be too soft. An alternative procedure is to pack the
ground fruit with 1 volume of 40° Brix cane-sugar sirup to 3 parts by
volume of the fruit ; exhaust 12-15 minutes at 200° F, seal, process at
212° until cooked to the desired extent, and cool thoroughly.

Figs are stemmed, washed, coarsely ground or sliced, mixed with 1
part of sugar to about 4 of fruit, heated to boiling, canned hot, sealed,
and processed at the boiling point about 1 hour (not less, in order to
avoid spoilage) , and cooled well.

Plums were made into a sauce by adding water to barely cover in a
kettle, adding 1 part of sugar to 4 of the mixture, cooking until soft,
canning scalding hot, processing a short time at the boiling point, and
cooling. Enameled type-L cans should be used for red plums.

These various sauces are not jams to be used as spreads on bread. They
are tart to mildly tart or only moderately sweet in taste and are to be
served as breakfast dishes and as light desserts. Those made from figs,
pears, peaches, and apricots are very useful in whips, gelatin desserts,
open pies, homemade ice cream, and puddings.

For further details see the references cited in footnote 47.

SIEVED FRUITS OR FRUIT PUREES

Sieved fruits are in considerable demand in canned form as foods for
infants. These products may be made from the fresh fruits by first pre-
paring them as for canning in the usual manner. They are then steamed
until soft and passed through a Sep-ro-siv type of apparatus (tomato-
juicer) or through a tomato-pulper (Cyclone). The hot puree may be
canned, sealed, and processed in boiling water until heated completely
through to not less than 190° F. Figs require a longer period at the boil-
ing point because their low acidity renders them very difficult to sterilize.
There is danger of botulinus poisoning from insufficiently sterilized fig
products. Acidification with about 0.5 per cent of citric acid before can-
ning is a great protection against such danger.

Dried prunes may be cooked with water until soft; then passed through
a tomato-pulper of sturdy construction; and the puree canned as de-
scribed for other fruits. Such prunes are of very heavy consistency and
require sweetening for the average adult. In the home they may be di-
luted with water and lightly sweetened for serving as breakfast drinks.
They are also useful in various frozen desserts, puddings, gelatin des-
serts, whips, and similar desserts.

At present sieved fruits are available to the housewife only in very
small cans or jars for infant feeding. Perhaps there would be a market
for these products in larger cans and jars for use in the home in the

Cir. 349] Utilization of California Fruits 39

various manners indicated above. The canning procedure is very simple
and inexpensive and fruit of the smaller sizes could be used. Therefore,
the retail price should be low.

BREAKFAST FRUITS

For many years canned and glass-packed "breakfast figs" have been
on the market. Most of the Kadota figs canned in this state and some of
the Texas variety are packed in this form ; that is, in a light sirup for
use as a breakfast dish. Recently other California fruits have appeared on
the market under this same title ; namely, as breakfast apricots, peaches,
and pears.

The fruit may be packed in the usual commercial manner in a light
sirup ; although, in order to set it off as a distinctly different product,
the fruit may be sliced or packed as a sauce as previously described.
Except for figs, the sirup should be approximately 20° to 25° Brix at
time of canning ; figs require a sirup of about 50° in order to "bring out"
their characteristic flavor.

Diced pears and peaches have been packed commercially in this man-
ner, but did not become popular.

Mixed fruits such as canned fruit cocktail are excellent as breakfast
dishes and for light desserts. For breakfast use, the mixed fruits should
be packed in somewhat lighter sirup than is used for the usual fruit
cocktail. The Maraschino cherries may be omitted in the breakfast mix
and the cost thereby considerably reduced. For breakfast use, we have
found, that the addition of some grapefruit juice to the sirup adds to
the flavor in a pleasing manner.

COFFEE SUBSTITUTES

For many years various coffee substitutes made from dried figs or
prunes or both admixed have been on the American market. The chopped
dried fruits may be roasted and coarsely ground for use in making
breakfast beverages free of caffein. Care must be taken in roasting in
order not to char the products unduly. Roasting should be conducted
with automatic control of temperature and time. Suitable controllers are
available.

If a roast low in sugar is desired, the sugars may be extracted from the
chopped fruit with hot water, the fruit then drained, dehydrated, and
roasted.

There are several fruitless coffee substitutes and decaffeinated coffees
of pleasing character available at relatively low price. Consequently we
doubt whether a very great potential market exists for fruit "coffees."

40 University of California — Experiment Station

VINEGAR

Vinegars have been made experimentally by commercial vinegar fac-
tories and by various research laboratories from many kinds of fruits.
In America, however, the average consumer is accustomed to use apple
vinegar chiefly ; those of southern European origin prefer wine vinegar.
Vinegar is a low-priced product and is used in limited quantities. That
is, price is of no particular importance in vinegar consumption as the
human organism's capacity for this product is definitely limited. Cull
apples and apple waste from apple dryers are the usual raw materials
and are worth only $1.50 to $3.00 a ton for vinegar making. We believe,
except for making small amounts of vinegar in the home, that the use of
other fruits for vinegar would be decidedly unprofitable. For details of
procedure see Circular 332.48

PICKLED AND SPICED FRUITS

Figs and peaches and to a lesser extent a few other fruits are packed
in glass or canned in a heavy vinegar sirup as "fruit pickles" or in a
lighter sirup as "spiced fruits."

In the preparation of fruit pickles in heavy sirup, the fruit prepared
as for canning is cooked in a spiced sirup in jelly kettles to a heavy pre-
serve, packed in glass, sealed, and pasteurized in the containers. The
following formula may be used or modified to suit the desires of the
operator : 20 gallons water

12 ounces dry gingerroot
14 ounces whole cloves
18 ounces stick cinnamon
3 gallons 40-grain cider vinegar
125-130 pounds sugar

The spices are placed in cheesecloth bags. The fruit is cooked in the
sirup to a preserve consistency, that is, to about 60 per cent sugar. It is
allowed to stand overnight to absorb sirup, then the spices are removed,
and the fruit is packed in vacuum-sealed preserve jars and pasteurized
at 175°-180° F for 30 minutes. If the fruit tends to shrivel during cook-
ing, it is blanched until tender in boiling water before cooking in the
sirup. Very tender fruits such as apricots may have to be placed in a
heavier sirup and cooked a shorter time. Some packers use the progres-
sive method of cooking, in which the fruit is cooked a short time on each
of several successive days in sirup increased in density each day by addi-
tion of sugar.

48Cruess, W. V., and M. A. Joslyn. Home and farm preparation of vinegar. Cali-
fornia Agr. Exp. Sta. Cir. 332:1-29. 1934.

Cir. 349] Utilization of California Fruits 41

Spiced fruits may be considered those canned or glass-packed directly
in a medium to medium-heavy, spiced, vinegar sirup. One procedure con-
sists in proceeding exactly as in the preparing of fruit pickles described
in the preceding paragraph to the point where the fruit is to be added;
except that only sufficient sugar is used to give a sirup of 40° Brix.

Instead of cooking the fruit in kettles in the sirup, it is packed in cans
of resistant tin plate such as type-L cans ; the spiced vinegar sirup is
added; and the cans exhausted in the usual manner, sealed, and processed
until the fruit is of desired texture. The time required will vary greatly
with the variety of fruit and whether it is packed whole or in halves. A
few pieces of cinnamon and cloves may be added to each package, if de-
sired, for the sake of appearance. Small cling peaches and small pears are
peeled and canned whole. In order to facilitate sirup penetration, cling
peaches should be cut to the pit with a knife or a cut made around the
pit with a pitting spoon. Apricots, plums, figs, and cherries are canned
whole. Of California fruits, figs, cling peaches, and apricots appear to
be best suited.

Pickled and spiced fruits are used as relishes or appetizers and in

salads.

FRUIT WINES

Wines made from grapes and hard cider made from apples are the
principal fruit wines throughout the countries of the temperate zones. On
the other hand, wines are made commercially in limited quantities from
berries, cherries, oranges, and pears; and dried figs and raisins have
been used for homemade wines. At present the market is well supplied
with grape wines and hard cider. Berries are not produced in surplus in
California. Because of these conditions, we doubt whether other fruit
wines made to sell at prices competitive with those of grape wines and
hard cider would be profitable or salable in appreciable quantities. On
the other hand, perhaps a moderate demand could be created for fruit
wines of the dessert or cordial type.

Governmental Regulations. — All alcoholic-beverage industries are un-
der strict state and federal control. No fermented beverage may be made
for sale until the necessary permits have been secured, and full, written
approval given by the various alcoholic beverage control and tax units.
Penalties for nonobservance are extremely severe ; prison sentences are
not uncommon for violations. For specific information, apply to the
State Liquor Control Board, Sacramento, and to the nearest office of the
Alcohol Tax Unit of the United States Bureau of Internal Revenue.

Grape Wines. — There are many books on wine making, the best of
which are listed at the end of Chapter XXX of Commercial Fruit and

42 University of California — Experiment Station

Vegetable Products (cited in footnote 15, p. 11). Bulletin 63949 discusses
the production of table wines and supersedes the dry-wine section of
Extension Circular 88,GO now out of print. Bulletin 65150a discusses the
production of dessert wines and supersedes the corresponding section
of Extension Circular 88. A description and discussion of commercial
wines and methods of production will also be found in Principles and
Practice of Wine Making?1 Much information can also be secured from
various journals.52

Hard Cider. — Hard ciders are of several types: (a) natural unforti-
fied, (b) sugared unfortified, (c) fortified, and (d) sparkling. The first-
named may be made and sold free of internal-revenue tax. The others
are termed "apple wines" and are subject to the respective state and
federal wine taxes and regulations.

In preparing natural hard cider, we have found that it is necessary to
apply sound wine-making practices. Selected pure yeast and a moderate
addition of sulfur dioxide (100-125 p. p.m.) should be used. Otherwise
the product is apt to be diseased and vinegar-sour. Commercial pro-
ducers find that the fermented product should be filtered brilliantly
clear, bottled, and pasteurized at 140°-150° F in the bottles. Prepared
in this manner, it is ready to use within a month after crushing and keeps
indefinitely. If stored in barrels as is grape wine, it is apt to become in-
fected with spoilage bacteria that cause it to sour and become "mousey."

Fortified apple wines are made in about the same manner as fortified
grape wines, as described by Cruess (references in footnote 15, p. 11 ; and
footnote 51) . The best fortified commercial cider that we have examined
was made by fortifying slightly fermented apple juice with apple brandy
of high quality to about 20.5 per cent alcohol. The brandy may be made
from cull apples, peels, and cores. In the production of fortified wines of
all kinds, the rules given by the Bureau of Internal Kevenue53 must be
followed. Braskat54 has recently given a good description of the produc-
tion of apple and other fruit wines in the Pacific Northwest.

49 Amerine, M. A., and M. A. Joslyn. Commercial production of table wines. Cali-
fornia Agr. Exp. Sta. Bui. 639:1-143. 1940.

50 Joslyn, M. A., and W. V. Cruess. Elements of wine making. California Agr. Exp.
Sta. Cir/88:l-64. (Out of print.)

50a Joslyn, M. A., and M. A. Amerine. Commercial production of dessert wines.
California Agr. Exp. Sta. Bui. 651:1-186. 1941.

51 Cruess, W. V. Principles and practice of wine making, vi 4- 212 p. Avi Publishing
Co., Inc., New York, N. Y. 1934.

52 Fruit Products Journal, Avi Publishing Co., Inc., New York, N. Y. ; Wine Re-
view, San Francisco, California; Wines and Vines, San Francisco, California.

53 United States Bureau of Internal Revenue. Regulation No. 7 relative to the pro-
duction, fortification, tax payment, etc., of wine. Federal Register 2:2467-2516. 1937.
Also issued as a reprint. 188 p. 1937.

54 Braskat, Norman, and H. A. Quinn. Apple wine. Wine Review 8(2): 6-8, 26-27.
1940.

Braskat, Norman. Fruit wines. Wine Review 7(12) :8, 26. 1939.

Cir. 349] Utilization of California Fruits 43

Sparkling* cider is usually made by the same methods as are in use for
sparkling wines. See Bulletin 639 (cited in footnote 49), and the book
cited in footnote 51 (p. 42) .

Perry. — In the preparation of perry, or fermented pear "cider," we
have found the procedure used for hard cider satisfactory. In brief it
was as follows : hard-ripe pears were crushed and pressed in apple-juice
equipment. Soft-ripe fruit cannot be pressed successfully. To the juice
was added 100-125 p. p.m. of sulfur dioxide in the form of sodium bisul-
fite (NaHSOg) , and a starter of 3 per cent by volume of active pure yeast
in sterilized fruit juice. After fermentation was complete, the new perry
was allowed to settle several days. It was then filtered and aged several
months in oak before bottling.

Berry Wines. — In preparing raspberry and Logan, Young, and Boy-
sen blackberry wines, the fruits were crushed coarsely ; given an addition
of 125-150 p. p.m. of sulfur dioxide, a starter of pure yeast, fermented
until soft (2-4 days), pressed, sweetened with cane sugar to bring alco-
hol x 2 + residual sugar to an amount equal to an original 22°-23° Brix
for table wines, and to 28°-30° Brix for dessert wines. Fermentation
then proceeded to completion. The new wines were then allowed to settle,
were racked, filtered, and aged in contact with oak. Sugar addition as
indicated is necessary because these fruits are lacking in it. We are op-
posed 'to the excessive watering of such wines as is done so commonly in
commercial practice. If the ripe California fruits are used, no water
should be added. Some unf ermented sugar should remain in the dessert
wines in order to give proper balance.

Cherry Wines. — Ripe black cherries should be used. It is desirable
that the pits be removed. The fruit is crushed, sulfur dioxide added as
described for berries, and the fruit fermented 3 to 4 days with pure
yeast. It is then pressed and treated as outlined for berries.

B$rry Cordials. — Berry juices are made into cordials by addition of
sugar and high-proof brandy. Special federal permission is required
and the tax is very high. Berry- wine and other fruit-wine production in
Europe is well described by Kroemer and Krumholz.55

Citrus Wines.- — Some orange wine similar to sherry, and some grape-
fruit wine have been made commercially. The sherry-type wine may be
made by fortifying with high-proof brandy the fresh juice, or that which
has been partially fermented by controlled pure-yeast fermentation; and
then settling, racking, filtering, and aging in the wood until of desired
flavor. Unfortunately, excessive darkening and undesirable changes in
flavor are apt to occur. Mild decolorizing of orange wine with vegetable

55 Kroemer, K., and G. Krumholz. Obst- und Beerenweine. 292 p. Serger und
Hempel, Braunschweig, Germany. 1932.

44 University of California — Experiment Station

decolorizing carbon will prevent these changes, according to Von
Loesecke, Mottern, and Pulley.56

Orange juice is an excellent medium for alcoholic fermentation, and
consequently high alcohol content may be attained by its fermentation.
In experiments in this laboratory, orange wines of 18 to 19 per cent
alcohol content have been attained by adding about 5 per cent of cane
sugar at intervals of 2 to 3 days during fermentation. Some excess of
sugar may be left to improve the flavor.

Wines of alcohol content corresponding to that of grape table wines
(11.0-13.5 per cent) can be made by fermentation of orange juice, and
grapefruit juice sweetened to 20°-24° Brix; and by usual cellar treat-
ment thereafter. The darkening problem and undesirable flavor changes
are problems here as with the fortified wines. Most consumers prefer
slightly sweet citrus wines to those sugar-free. Grapefruit wine is on the
average superior to the orange in flavor and color.

Dried-Fruit Wines. — Infusions may be made from dried fruits by hot
extraction with several changes of water, and fermentation of the in-
fusion with pure yeast. Or the dried fruits may be covered with cold
water, fermented with added yeast until soft, and pressed, and the re-
sulting infusion fermented to completion.

Such "wines" however, are very poor substitutes for fresh-fruit wines,
and should be used only for distillation for brandy.

FRUIT BRANDIES

In France and most other Mediterranean countries, grape brandy
and certain fruit brandies, such as Calvados (a famous French apple
brandy), Kirsch (cherry brandy), and arrack (date brandy), are more
generally used than is whiskey ; in the United States, the British Isles,
and northern Europe, the reverse is true. Perhaps with proper advertis-
ing of high-quality fruit brandies, some increase in their consumption
could be attained.

In small-scale tests and by use of a very small registered experimental
still, we have made small quantities of plum, peach, apple, and pear
brandies from the fresh fruits, and prune, fig, and date brandies from
the dried. The fresh fruits were crushed, fermented with pure yeast and
sulfur dioxide (100 p.p.m.), pressed, and the wine distilled to 130-140
proof ; the distillate diluted to 100 proof, and aged in bottles in contact
with oak shavings. The dried fruits were covered with water and then
handled as described for the fresh.

56 Loesecke, H. W. von, H. H. Mottern, and G. N. Pulley. Wines, brandies and
cordials from citrus fruits. Industrial and Engineering Chemistry, industrial edition
28:1224-29. 1936.

Cm. 349] Utilization of California Fruits 45

The amounts made were altogether too small to secure accurate data
on yields, but the flavor and bouquet of the aged brandies were of inter-
est. The best brandies were those in which considerable of the "heads"
and "tails" (aldehydes and fusel oils) of the distillation were retained.
Those distilled to a nearly neutral brandy developed very little char-
acter. On the other hand, too much "heads" or "tails" will give a harsh,
disagreeable product.

The details of factory design and equipment, government regulations
and taxes, aging, and other details are beyond the scope of this circular.
For further information see books57 on the subject and Bulletin 652.57a

In general it may be said that the equipment needed for a brandy dis-
tillery is costly, the federal regulations very strict ; the taxes very high,
and the manufacture of high-quality brandies a difficult art. In addition,
the product should be aged slowly in the wood for at least three years ;
therefore, heavy capital outlay is required. For these reasons, fruit-
brandy production should be undertaken only by those who are well
financed and who have or can secure experienced personnel.

VALUE OF FRUITS IN THE DIET

Fruits are very valuable in the diet, and most Americans could use
more fruits and fruit products with benefit to health. They provide valu-
able vitamins, particularly C (the antiscorbutic or antiscurvy vitamin) ,
G (riboflavin) of great dietetic importance, A (the "anti-infective" vita-
min), and some Bt (the antineuritic vitamin). Most fruits, on digestion,
exert a marked basic reaction in the body, and thus counteract the acid
residues of some other foods. Some fruits, particularly the stone fruits,
are valuable in combatting anemia. Most are valuable sources of impor-
tant minerals ; and most fruits exert a mild laxative action, owing to
the bulk effect or to the presence of laxative substances.

Those who wish to obtain specific information on this and related sub-
jects concerning human nutrition may consult any authoritative book
on nutrition.58 The 1939 United States Department of Agriculture Year-
book is an excellent reference on the subject.

57 Hirstein, K. M., and T. C. Gregory. Wines and liquors, xii + 360 p. D. van
Nostrand Co., New York, N. Y. 1935.

Hirsch, I. Manufacture of whiskey, brandy and cordials, xvii 4- 136 p. Sherman
Engraving Co., Newark, N. J. 1934.

B7a Joslyn, M. A., and M. A. Amerine. Commercial production of brandy. California
Agr. Exp. Sta. Bui. 652:1-80. 1941.

58 Sherman, H. C. The chemistry of food and nutrition. 640 p. The Macmillan Com-
pany, New York, N. Y. 1938.

McCollum, E. V. The newer knowledge of nutrition. 5th ed. 701 p. The Macmillan
Company, New York, N. Y. 1939.

United States Department of Agriculture. Food and life, U. S. Dept. Agr. Year-
book 1939. xv + 1165 p. 1939. For sale bv Superintendent of Documents, Washington,
D. 0., for $1.50.

46

University of California — Experiment Station

BY-PRODUCTS

The preceding sections have dealt chiefly with the utilization of fruits
of edible quality. In addition, there are often large quantities of certain
fruits unsuitable for food purposes and of waste fruit materials such as
fruit pits, pomace (press cake) , still slops, peels, and cores. Some of these
cull fruits and waste products are utilized in part ; others are discarded.

Fig. 9. — Grape pomace mixed with lime, for use as a fertilizer.

For example, grape pomace is often used as a low-grade fertilizer. See
figure 9.

Space will not permit a detailed presentation of the manufacture of
various by-products from fruit wastes. The more important products
will be discussed briefly, and the general procedures and sources of in-
formation will be indicated.

Industrial Alcohol. — The Station receives many inquiries from grow-
ers, promoters, and fruit processors for information on establishing
"power" alcohol factories, and the production of "power" alcohol. A
great deal of ill-advised, promotional literature has appeared on the
subject, and a number of attempts have been made to persuade fruit
growers to invest in such plants.

Cir. 349]

Utilization of California Fruits

47

From a consideration of possible yields and returns, the utilization of
fruits for industrial alcohol, including that for possible admixture with
gasoline, does not appear inviting. A very useful publication59 has re-
cently appeared on the subject of alcohol and other motor fuels from
farm products. The authors, Jacobs and Newton, estimate the approxi-
mate yields of alcohol from various fruits as shown in table 2. "We have
in addition calculated the value of the alcohol from 1 ton of each fruit
at 30 cents a gallon.

Jacobs and Newton call attention to the fact that "power" alcohol
(anhydrous 100 per cent, 200-proof ethyl alcohol) from fruits, potatoes,

TABLE 2

Approximate Commercial Yields of 99.5 Per Cent Alcohol from

One Ton of Various Fruits

Fruit

Apples, average fresh

Apricots, fresh

Dates, dry

Figs, fresh

Figs, dry

Grapes, eastern

Grapes, California. . .

Peaches, fresh

Pears

Plums

Prunes, dry

Raisins

* From: Jacobs, P. B., and H. P. Newton. Motor fuels from farm products.
U. S. Dept. Agr. Misc. Pub. 327:1-129. 1938.
t Estimate by present authors.

and other crops must compete with that made from molasses, a very low-
priced product. Table 3 gives their estimated costs of 100 gallons of
alcohol from various raw materials.

To these costs must be added sales costs and overhead costs such as
taxes, insurance, depreciation, and office expense. Ash60 of the California
Packing Corporation estimates the cost of making alcohol from a fruit
at not less than 15 cents a gallon exclusive of cost of fruit. But accepting
the estimates given by Jacobs and Newton, it can be seen that at a good
price of 30 cents a gallon the manufacturer would lose 11.41 cents on
each gallon of alcohol made from apples or about $1.63 for each ton,
assuming he pays $5.00 a ton for the raw material.

B9 Jacobs, P. B., and H. P. Newton. Motor fuels from farm products. U. S. Dept.
Agr. Misc. Pub. 327:1-129. 1938.

60 Ash, Chas. Personal communication.

48

University of California — Experiment Station

Cull dried fruits unfit for any other purpose appear somewhat more
practicable than the fresh as sources of alcohol. Thus, at 30 cents a gallon
for alcohol, raisins would appear to barely return the manufacturer his
costs, if he pays $20.00 a ton for the raw material.

The market for alcohol for general industrial use (not for power pur-
poses) in varnishes, for other solvent purposes, and as a base for prep-
aration of other industrial compounds is well supplied at present with
alcohol from molasses. There is, therefore, no present need for use of
more expensive raw materials. In addition, alcohol can be made cheaply
from petroleum products, or from acetylene made from lime and coal,
or from wood waste.

TABLE 3
Comparison of Costs of Alcohol from Various Eaw Materials*

Raw material

Price of raw

material per

ton

Cost of raw

material for

100 gallons

of alcohol

Probable
manufactur-
ing cost per
100 gallons
of alcohol

By-product
credits per
100 gallons
of alcohol

Net cost of
100 gallons
of alcohol

Net cost
per gallon

Molasses

dollars
8.50
20.00
10.00
5.00
20.00

dollars
12.24
23.80
43.70
35.00
22.80

dollars
8.00
10.80
11.15
9.50
9.00

dollars
1.90
5.91
4 32
3 09
2.25

dollars
18.34
28.69
50.53
41.41
29.55

cents
18.34
28.69

50 53

Apples

Raisins

41.41
29.55

* From: Jacobs, P. B., and H. P. Newton. Motor fuels from farm products. U. S. Dept. Agr. Misc. Pub.
327:1-129. 1938.

Jacobs and Newton estimate the cost of an alcohol factory to produce
2,500 gallons of alcohol daily at $200,000, and one for 10,000 gallons
daily at $575,000.

Stock Feeds. — Some agricultural wastes are now used for stock feed.
Among these are dried citrus-fruit peels, dried apple pomace, dried
grape pomace, cull raisins, cull dried prunes, and cull dried figs. Some
surplus dried fruits of edible quality are also utilized, after suitable
denaturing for human consumption. Grape pomace, apple pomace, and
other fruit wastes are dried for stock feed in rotary drum driers heated
directly by the products of natural-gas combustion, or indirectly by
steam pipes. See figure 10.

The Station has conducted animal feeding tests61 with a number of

01 Mead, S. W., and H. E. Guilbert. The digestibility of certain fruit by-products
as determined for ruminants. I. Dried orange pulp and raisin pulp. California Agr.
Exp. Sta. Bui. 409:1-11. 1926. (Out of print.)

Regan, W. M., and S. W. Mead. The value of orange pulp for milk production. Cali-
fornia Agr. Exp. Sta. Bui. 427:1-16. 1927. (Out of Print.)

Miller, Robert F. Raisin by-products and bean screenings as feeds for fattening
lambs. California Agr. Exp. Sta. Bui. 431:1-16. 1927. (Out of print.)

Mead, S. W., and H. R. Guilbert. The digestibility of certain fruit by-products as

Cir. 349] Utilization of California Fruits 49

fruit wastes. The reader is referred to these for further details. In most
cases the fruit wastes were fed in dry form. The feeding value of most of
them is somewhat less than that of barley ; and most are decidedly low
in protein content. Their principal value is as a source of carbohydrates.
Some, such as prunes, furnish considerable vitamin A. Dried grape
pomace from wineries was found to be only 30 to 40 per cent as valuable
as rolled barley, and about 60 per cent as valuable as good hay for use
as stock feed. This material has been much overrated by the industry.
One advantage in using waste fruits for animal feeding is that several

Fig. 10. — Plant for preparing dried stock feed from citrus peels.

pounds of the product is required to produce one of meat or one of dried
milk. Consequently, human consumers have to eat perhaps only one
sixth to one eighth as much of the end product (expressed on a dry basis)
as of the fruits. Another advantage is that processing (drying) of the
wastes is simple, and another is that the market is near at hand, namely,
on the farm. Usually dairies, beef -steer feeding lots, or hog farms are
near the source of the raw material; hence transportation costs are low.
Dried grapefruit refuse has been shown to be 82.8 per cent digestible,
and dried orange refuse to be 80.8 per cent, according to research done

determined for ruminants. Part II. Dried pineapple pulp, dried lemon pulp, and
dried olive pulp. California Agr. Exp. Sta. Bui. 439:1-11. 1927. (Out of print.)

Hughes, E. H. The feeding value of raisins and dairy by-products for growing and
fattening swine. California Agr. Exp. Sta. Bui. 440:1-12. 1927. (Out of print.)

Regan, W. M., and G. E. Gordon. Fruits and fruit by-products as dairy cattle
feeds. 2 pages. University of California Agricultural Extension Service, Berkeley,
California. 1934.

Folger, A. H. The digestibility of ground prunes, winery pomace, avocado meal,
asparagus butts, and fenugreek meal. California Agr. Exp. Sta. Bui. 635:1-11. 1940.

50 University of California — Experiment Station

in Florida62 on the value of citrus wastes. The digestibility figures place
them in the class of high carbohydrate concentrates.

At the Virginia Agricultural Experiment Station03 the digestibility
of dried apple pomace from cider mills was determined, and found to be
about 67 per cent. Some of this product is used in California in a mixed
ration for dairy cattle by the Brown Dairy, Santa Cruz County.

Neal, Becker, and Arnold (cited in footnote 62) give the values shown
in tables 4 and 5 for composition and coefficients of digestibility of vari-
ous fruit products. From these tables one may compare the composition
of the dried meals and their relative values as stock feeds as shown by
their digestibilities. For a full discussion of this subject, see the various
publications cited (footnotes 61 to 63) . Unfortunately most of these are
out of print; but they may be consulted in any university or first-class
technical library; those published by the California Agricultural Ex-
periment Station are available in many city and county libraries in
the state.

Pit By-Products. — Apricot pits are collected from dry yards and can-
neries after drying in the sun and are cracked in plants in the Santa
Clara Valley. The kernels are separated from the shells by brine flota-
tion. Most of the kernels are shipped to eastern United States or to
Europe for use in preparing sweet oil for pharmaceutical and other
purposes, and imitation "bitter-almond" oil for use in flavoring extracts.
The shells are carbonized in continuous destructive stills. See figure 11.
Formerly the pyroligneous distillate, containing methyl alcohol, acetic
acid, and tar, was recovered, and some of the constituents purified. At
present, owing to other and cheaper sources of these compounds, the
distillate is not utilized. The gaseous compounds are burned as fuel in
the distillation. The carbonized shells are crushed, screened, and sold for
mixing in poultry feeds, or are treated for use in casehardening of steels.
They have high gas-absorbing power, consequently were in demand in
the first World War for use in gas masks.

Apricot pits yield about 23-25 per cent of kernels ; peach pits only
about 7 per cent. It is very difficult to recover the kernels from peach
pits. Consequently, they are dry distilled directly for carbon.

62 Neal, W. M., E. B. Becker, and P. T. Dix Arnold. Dried grapefruit refuse — a
valuable feed. Florida Agr. Exp. Sta. Press Bui. 466:1-2. 1934.

Neal, W. M., R. B. Becker, and P. T. Dix Arnold. The feeding value and nutritive
properties of citrus by-products. Florida Agr. Exp. Sta. Bui. 275:1-26. 1935.

Pulley, G. N., and H. W. von Loesecke. Drying methods changes composition of
grapefruit by-products. Food Industries 12(6) :62-63, 100-1. 1940.

63 Holdaway, W. C, W. B. Ellett, J. F. Eheart, and M. P. Miller. The importance of
properly balanced rations in trials to determine digestibility as shown in experi-
ments with dried apple pomace. Virginia Agr. Exp. Sta. Tech. Bui. 32:1-18. 1927.

Cib. 349]

Utilization of California Fruits

51

Cherry pits may be used in the same manner as apricot pits, although
those from brined cherries are said to be of little value.

The procedures generally followed in producing sweet oil and "bitter-

TABLE 4
Composition of Certain Fruit By-products*

Product

Dry

matter

Crude
protein

Crude
fiber

N-free
extract

Crude
fat

Ash

per cent
87.50
92.90
88.68
83.60
92.02
95.11
86.68
91.77
93.00

per cent
7.70
6.39
9.58
3.81
5.91

13.99
4.31
4.94

11.80

per cent
7.81
15.00
19.32
13.88
36.45
19.27
17.03
11.94
34.02

per cent
66.96
65.24
45.57
61.94
31.54
31.04
69.76
69.60
36.31

per cent

1.68

1.23

10.54

0.71

15.63

27.39

5.13

1.06

4.52

per cent
3.35

5.04

3.67

Pineapple pulp

Olive pulp

Olive pulp (pitted) ...

Apple pomace

Grapefruit pomace ....
Winery pomacef

3.26
2.49
3.43
3.77
4.23
6.35

* All except winery pomace from: Neal. W. M., R. B. Becker, and P.T. Dix Arnold. The feeding value
and nutritive properties of citrus by-products. Florida Agr. Exp. Sta. Bui. 275:1-26. 1935.
t From: Cruess, W. V. (Unpublished data.)

TABLE 5
Coefficients of Digestibility of Fruit By-Products*

Product

Orange pulp

Lemon pulp ....

Raisin pulp

Pineapple pulp.

Olive pulp

Apple pulp

Grapefruit pulp.
Winery pomacef

Dry
matter

per cent
89.33
81.43
44.78
74.56
19.09
67.00
82.80
27.30

Crude
protein

per cent
78.54
46.18
24.13
20.75
Slight
37.00
24.83
16.10

Crude
fiber

per cent
83.73
60.33
18.54
69.62
Slight
54.00
71.52
27.10

N-free
extract

per cent
95.40
92.01
52.01
79.75
20.27
80.00
92.43
23.00

Crude
fat

per cent
48.89
27.44
90.16
Slight
86.02
32.00
79.37
71.60

* All except winery pomace from: Neal, W. M., R. B. Becker, and P. T. Dix Arnold. Florida Agr. Exp.
Sta. Bui. 275:1-26. 1935.

t From: Folger, A. H. The digestibility of ground prunes, winery pomace, avocado meal, asparagus
butts, and fenugreek meal. California Agr. Exp. Sta. Bui. 635:1-11. 1940.

almond" oil from fruit kernels are described by Cruess (cited in foot-
note 15, p. 11) and by Rabak.64

Grape Seeds. — The seeds resulting from the seeding of muscat raisins
are mixed with water, and the adhering sugar-containing pulp fer-
mented. High-proof brandy is recovered by distillation. The seeds are
dried, crushed, and pressed for oil used in coating muscat raisins against

84 Babak, F. Peach, apricot and prune kernel as by-products of the fruit industry in
the United States. U. S. Bureau of Plant Industry. Bui. 133:7-34. 1908. (Out of
print.)

52

University of California — Experiment Station

sugaring and in other industrial processes. The press cake may be used
as a low-grade stock feed in mixed rations. It is very high in crude fiber.
Seeds are separated from winery pomace in European countries by
sifting and winnowing, and are used for fixed oil production. In experi-
ments conducted in this laboratory,65 seeds were separated from dried
pomace by screening. Oil was extracted by trichloroethylene from the
ground seeds. The seeds contained an average of about 10 per cent of oil.

Fig. 11. — Fruit-pit by-products plant.

Tannin may be extracted from seeds from natural, dry-wine pomace ;
those from sweet- wine pomace are practically devoid of tannin because
of previous extraction with water for recovery of alcohol.

Olive Pomace. — In Italy, France, and Spain, olive pomace is de-
hydrated and extracted with carbon disulfide, gasoline, or trichloro-
ethylene.60 The solvent is removed by distillation, and the residual oil
sold for soap making, or refined for use as edible oil. In Bari, Italy, many
factories are operated for the production of refined, edible oil from the
pomace.

In California most of the pomace is utilized as fuel, although recently

05 Cruess, W. V., and C. A. Weast. The utilization of pomace and still slops. Wine
Review 7(2) :10-14, 27. 1939.

66 Cruess, W. V. Olives in Egypt and Italy. Fruit Products Journal 19:11-16, 25, 28.
1939.

Cm. 349] Utilization of California Fruits 53

two solvent-extraction plants have been established in the San Joaquin
Valley.

Other By-products. — A number of the products discussed in previous
sections, such as fruit vinegars, wines, sirups, brandies, juices, jelly
juices, and others are in the nature of by-products if off-grade fruits and
fruit wastes are used as raw materials.

Pectin and essential oils are made from citrus peels, and citric acid is
made from the juice. Most of the surplus lemons of this state are so
utilized with the purpose of removing them from the fresh-fruit market,
regardless of the returns from the by-products. The enhanced value of
the remaining fresh fruit is considered the main objective. The processes
used have been outlined by Wilson (footnote 27, p. 20) . See also Cruess
(footnote 15, p. 11) and Poore.67

Pectin, as previously stated, is used in the manufacture of jellies,
jams, and preserves. Nonfood uses are being investigated by several re-
search laboratories. Citrus oils are used in soaps, cosmetics, and flavoring
extracts.

Citric acid (see references in footnotes 15 and 27, p. 11 and 20) is an
important lemon by-product. The California Fruit Growers' Exchange
has been responsible for the establishment and development of the manu-
facture of this acid as well as of essential oil, and pectin from cull and
surplus lemons.

At present severe competition exists between citric acid from lemons
and that made synthetically from sugars by the use of certain molds.
Citric acid is also made in Hawaii in considerable quantities from pine-
apple waste.

From the waste lees (sediment) from wine is recovered high-proof
brandy for fortification of dessert wines, and cream of tartar, used in
baking powder.

A very useful recent publication dealing with various aspects of the
problem of utilization of various surplus crops is that of the United
States Department of Agriculture.08 on the survey for the Regional Re-
search Laboratories. These laboratories, four in number, will be devoted
to research on the utilization of surplus plant and animal agricultural
products.

67 Poore, H. D. Citrus pectin. U. S. Dept. Agr. Dept. Bui. 1323:1-19. 1925.

68 Anonymous. Regional research laboratories, Department of Agriculture. 76tli
Congress, Senate Document 65:1-429. 1939.

15m-ll,'41(4308)