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Contribution from the Bureau of Plant Industry
WM. A. TAYLOR, Chief

Washington, D. C. PROFESSIONAL PAPER December 30, 1915

MILLING AND BAKING TESTS OF WHEAT CON-
TAINING ADMIXTURES OF RYE, CORN COCKLE,
KINGHEAD, AND VETCH.

By, Ri. .C. Miter, Assistant in Charge of Dockage Investigations, Office of Grain

Standardization.
CONTENTS.

: Page. Page
MGrOdUCTIOMMMY S26 oo 2s 8 oo Ss Sacks 1S iRestsawithiflouniblendse ss.) see -~aseae saan 17
Frequency otf occurrence of impurities in Tests with wheat containing kinghead seed. - 18

WAGER Res Se Selec ee eae cc ta eee ee 2 | Testswith wheat containing wild-vetch seed,
Comparison of the specific gravity of wheat HES BTOWIs c= 58 See. 2 Soe ee aE eae 19

andvoieitsimlpunitiesss.ss4-cs-sscees ss snes 2 | Analyses of wheat, of the impurities, and of
Methods of preparation and milling-------_-. 3 flour containing admixtures. .............. 20
Descriptions of the different impurities... ... ® | ‘Specialicleaning devices. .--- 2.222.255.2260 22
Comparative milling yields of wheat and of Mechanical analyses of corn-cockle screenings. 22

TTS) UO OUT BIL (IRE STS ees ee peda Fe 1Oe|#Summeary ose. 22 ee soos ee eee eee 23
Milling and baking tests of wheat contain-

THAR THOCY OBLONG TES ey es mesial ALS Rech aa 10

INTRODUCTION.

Wheat as grown and as marketed frequently contains various kinds
of so-called inseparable impurities, such as rye (Secale cereale), corn
cockle (Agrostemma githago), kinghead, or great ragweed (Ambrosia
tryfida), and wild vetch (Vicia angustifolia). These impurities are
considered inseparable, inasmuch as they are not readily removed
from wheat by the grain-cleaning machinery in general use in grain
elevators and flour mills, because of their similarity in size, shape,
and specific gravity to the wheat in which they occur.

Millers claim that the presence of these impurities in wheat in
appreciable amounts injures the milling and baking qualities of the
flour. The result is that wheat which contains a noticeable amount

of these ingredients when marketed is generally penalized by being

as —— eee eee
Notre.—The data presented in this bulletin are applicable to the, wheat-producing sections of the
‘United States and are of interest to farmers, grain dealers, flour millers, and bakers.

10373°—Bull. 328—15——1

DD BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE.

given a lower commercial grade or by a reduction in price, as com-
pared with wheat that is free from such impurities. Special experi-
ments to determine the effects that these impurities have on the
millng and baking qualities of wheat were begun in 1912 by the
Office of Grain Standardization and were continued in 1913 and 1914.
The results of milling and baking experiments with wheat con-
- taining various amounts of rye, corn cockle, kinghead, and vetch show
conclusively that these impurities have detrimental effects on the
quality of the flour.t. Further experiments are planned with such
impurities as rye, barley, wild oats, kafir, and wild-rose seed, and also
with sprouted and bin-burnt wheat. |

FREQUENCY OF OCCURRENCE OF IMPURITIES IN WHEAT.

A study of the analyses of samples of wheat secured from the crops
of 1911, 1912, and 1913, as grown and as marketed, shows that a
large percentage of the samples of spring and durum wheat contained
rye, barley, oats, wild oats, corn cockle, kinghead, and wild-rose seed,
and that wild vetch is sometimes found in appreciable amounts.
Rye was found in 83.1 per cent of the hard winter-wheat samples
secured. This information is given in Table I.

TaBLE I.—Wheat samples from the crops of 1911, 1912, and 1913, which contained cer-
tain impurities, showing the percentage of each impurity found.

COMPARISON OF THE SPECIFIC GRAVITY OF WHEAT AND OF ITS
IMPURITIES.

The specific gravity of wheat varies with the type or class and
also with the quality. The average specific gravity of a number of
samples of soft wheat, determined in connection with investigations
with grain, was 1.3891, with a range between 1.3616 and 1.4133,
of the Office of Grain Standardization, who made all the baking and practical tests with the flour, assisted

by W. K. Marshall, aid in grain standardization, and to Thomas Sanderson, in charge of the experimental
mill of the North Dakota Agricultural College, who made the milling tests. ‘

MILLING AND BAKING TESTS OF WHEAT. 3

while the average specific gravity of a number of samples of hard
wheat was 1.4273, the range being from 1.4152 to 1.4427.

Roberts! found a range in specific gravity between 1.227 and 1.386
in tests with 52 different types of wheat.

In his studies of various kinds of seeds Nobbe? gives the average
specific gravity of 30 samples of wheat as 1.4131, with a variation
between 1.3766 and 1.4396. The specific gravity of various other
seeds is also given, viz, corn cockle (Agrostemma githago), 1.233; rye,
for different tests, 1.325 and 1.371; barley, 1.351. The specific
sravity of different species of vetch (Vicia) is given as follows: Vicia
benghalensis, 1.344; Vicia dumetorum, 1.203; Vicia faba, 1.298; Vicia
lutea, 1.273; Vicia monanthos, 1.327; Vicia narbonensis, 1.300.

Table II gives a comparison of the specific gravity of wheat with the
specific gravity of several impurities very frequently found in wheat.
These figures represent but one test of the impurities used in the milling
and baking tests described in the following pages. It will be noted
that the corn-cockle seed has a specific gravity nearly equal to that
of wheat,’ while rye and hairy vetch have a greater specific gravity
than wheat. The samples of rye, barley, kafir, and hairy vetch
were cleaned with a small milling separator to remove any foreign
matter, such as chaff or dirt, and the small and light kernels were also
removed. The samples of rye and hairy vetch were possibly above
the average quality. This is indicated by the test weight per bushel
after the samples were cleaned. The rye weighed 58 pounds and the
hairy vetch 64 pounds per bushel in comparison with 57 pounds per
bushel, the test weight of the wheat used in the various tests with the
different impurities. The kinghead seed, though having a smaller
specific gravity than wheat, is somewhat larger and is not readily
removed with ordinary mill cleaning machinery.

TaBLE I1.—Specific gravity of wheat and of certain impurities frequently found.

Pee au Sp. er. Impurity. Sp. gr. Impurity. Sp. gr. Impurity. Sp. gr.
Wheat (spring). -| 1.3992 || Barley.......-. 13425) P otieeeeeee 1.3175 || Corn cockle....-.- 1.3915
TRAC Suet 1.4097 || Wiid oats...... 1. 3320 || Kinghead....-- . 9563 || Hairy vetch....| 1.4888

Figure 1 shows the comparative size and shape of wheat and rye
kernels and of seeds of corn cockle, hairy vetch, kinghead, and wild
vetch.

METHODS OF PREPARATION AND MILLING.
To insure greater uniformity in the different tests, a sufficient

quantity of wheat of one variety was purchased each year to make all
the milling tests desired. Thus, the samples milled and used as

1 Roberts, H. F. Breeding for type of kernel in wheat. Kans. Agr. Exp. Sta. Bul. 170, p. 108-114, 1910.
* Noble, Friedrich. Handbuch der Samenkunde, p. 315-319. Berlin, 1876.

4 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE,

checks in each experiment are comparable with the samples con-
taining the different impurities.

The wheat used in the experiment was thoroughly cleaned and
scoured before making up the milling samples containing the various
admixtures of rye, corn cockle, kinghead, and hairy vetch. This was
done because the samples were neither cleaned nor scoured after the
mixing, since it was desired that a definite known percentage of any
added impurity should go to the rolls for milling into flour, bran, and
shorts.

Each sample milled consisted of 100 pounds, including the impurity
(e. g., 99 pounds of wheat and 1 pound of corn-cockle seed; 98 pounds
of wheat and 2 pounds of corn cockle seed, etc.). The samples were

Fic. 1.—Grains of rye (A) and wheat (B); seeds of corn cockle (C), hairy vetch (D), kinghead ( £), and
wild vetch (F). On account of the shape, size, and specific gravity of these impurities they are not
easily separated from wheat. (Natural size.)

milled at the North Dakota Agricultural College in the experimental
mill, which has a capacity of 50 barrels per day of 24 hours.

To obtain results which would be comparable with average com-
mercial conditions at country points, the methods of milling used in
country mills were followed in general in the tests with the so-called
inseparable impurities. The flour yields obtained compare very favor-
ably with those secured by well-equipped country mills of 50 to 100
barrels daily capacity, since it was possible in milling the samples to
make five breaks and as many reductions as desired, up to seven or
eight.

In the tests covering the three years, the samples were milled as
straight flours (that is, only one grade of flour was made from the

MILLING AND BAKING TESTS OF WHEAT. 5

total flour obtained) and, in addition, in the 1913 tests, three grades
of flour, viz, patent, first clear, and second clear, were made from
wheat containing 10 per cent admixtures of rye, corn cockle, king-
head, and hairy vetch, in order to study the effects of a large percent-
age of these different impurities on each grade of flour.

In the 1912 and 1913 tests where the one grade (straight flour) was
made, the percentages of impurities used in the admixtures were 1, 2,
3, 5, and 10, except that in the 1912 experiment with corn cockle
tests were made with but 1, 2, and 3 per cent. In 1914 the milling
tests were continued with samples of wheat with admixtures, viz,
1,2, and 3 per cent each of corn cockle and kinghead, and 1, 2, 3, and
5 per cent of rye. No milling tests were made with admixtures of
hairy vetch, as the experiments of 1912 and 1913 showed very con-
clusively the detrimental effects which this impurity has on the
milling and baking qualities of wheat and flour.

Samples of wheat which contained large amounts of wild-vetch seed
were secured by the writer from the 1914 crop as marketed by farmers
at country points, and the results of the milling and baking tests of
these samples are given in Table IX (p. 20). The results show that
the detrimental effects of hairy vetch and of wild vetch in wheat as
milled are very similar in character.

DESCRIPTIONS OF THE DIFFERENT IMPURITIES.

RYE.

Rye (Secale cereale) is the impurity most common and abundant in
hard winter wheat. Millers object to its presence, claiming that it
injures the color of the flour, but the opinions of millers differ greatly
as to the amount of rye that may be present in wheat before the
color of the flour will be affected. Some millers contend that 2 per
cent of rye in wheat will injure the color of the flour, while others
hold that amounts up to 5 per cent will not noticeably affect the
quality of the flour or bread.

Rye was also found in 39.2 per cent of the spring-wheat samples
secured, as indicated in Table I, and in one case the farmer’s wheat
crop. contained 14.3 per cent. On account of the excessive amount
of rye in this wheat the farmer received 8 cents less per bushel than
he would have received had the grain been free from rye. The
presence of rye in a considerable percentage of the samples examined
was probably due to the fact that wheat containing rye was used
for seeding purposes. Frequently wheat is sown on land which was
planted in rye the previous season, and the rye shattered during
harvest produces a volunteer crop which matures and is harvested
with the wheat. Where the wheat crop partially winterkills, the per-
centage of rye is considerably increased, as rye is not so subject to

6 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE,

winterkilling as wheat. Baking tests with flour milled from wheat
samples containing different percentages of rye showed detrimental
effects on both the color and the texture of the crumb when above 3
per cent of this impurity was added to the wheat. }

Examinations of samples of flour milled from wheat which con-
tained various percentages of rye showed the presence of a consider-
able number of grayish and greenish yellow specks, especially in the
samples containing more than 3 per cent of this ingredient.

Wheat containing a 3 per cent admixture of rye will yield a darker
colored flour, showing quite distinctly toward the tail of the mill.
When rye is milled alone about 48 per cent of flour is obtained, as
shown in Table III (p. 10). Rye flour does not bolt freely, but
when blended with wheat in small amounts it seems to cause very
little trouble in bolting, since the wheat flour aids the rye flour in
passing through the bolting cloth. The fact that the flour yield
was but slightly reduced even in samples of wheat with 5 per cent

Fic. 2.—Wheat containing 6 per cent of corn-cockle seed and 8.7 per cent of other foreign matter, as
delivered at a country elevator. (Natural size.)

or more of rye would indicate that a large proportion of the rye
flour bolted through with the wheat flour. When wheat containing
10 per cent of rye was milled into three grades of flour, the injurious
effects of rye were most pronounced in the second-clear flour, as
evidenced in the baking results given in Table VI (p. 16).

CORN COCKLE.

Corn cockle (Agrostemma githago) is an annual prolific weed, the
seed of which is rough, black, and of such a shape and size as to
make it difficult to separate from wheat. It is very common, being
widely distributed over the United States, and is especially abundant
in the sections producing soft red winter, spring, and durum wheats.
It is not an uncommon occurrence for wheat to contain 1 or 2 per
cent of this weed seed, and occasionally 5 or 6 per cent of corn cockle
is present in the grain as marketed (fig.2). The presence of 1 or 2 per
cent of corn cockle in wheat is likely to lower the grade or price given
the farmer and will lower the baking qualities of the flour. The fact

MILLING AND BAKING TESTS OF WHEAT. a

that a single plant of corn cockle has been known to yield as high
as 2,500 seeds shows it to be an exceedingly prolific and obnoxious
weed, which every farmer should strive to eradicate or prevent from
getting a start if the farm is not infested.

In milling wheat containing but 1 per cent of corn cockle, black
specks, which are finely broken pieces of the outer covering of the
seed, appear in the flour. When milled alone, corn-cockle seed will
yield from 45 to 50 per cent of flour having a bluish white color and
aspecky appearance. Baking tests of three grades of flour milled
from wheat containing 10 per cent of corn cockle indicated that this
impurity was well distributed in each grade of flour (Table VI,
p- 16).

Figure 2 Team ont a sample of spring wheat obtained by the

writer from a farmer’s wagon as the grain was unloaded at a country
grain elevator. The mechanical analysis of this sample showed it to
contain by weight 6 per cent of corn cockle, 1 per cent of wild buck-
wheat, and 7.7 per cent of other grains, which consisted of oats,
wild oats, and barley.

The presence of such an amount (6 per cent) of corn cockle in this
wheat resulted in a loss to the farmer, not only in the lower price per
bushel which he received but in addition a dockage was assessed.

This term ‘‘dockage”’ is used with reference to the foreign matter
present in wheat when marketed. It is the custom in the States
producing spring wheat which contains a considerable quantity of
foul weeds and other foreign matter to, deduct from the gross weight
of the load a certain amount expressed in pounds per bushel. For
example, if a load of 50 bushels of wheat is found to contain 2 pounds
of foreign matter for each bushel, then 100 pounds is deducted from
the gross weight, and the owner of the grain receives pay for 50
bushels less the 100 pounds of dockage, or 48 bushels and 20 pounds
of wheat.

KINGHEAD, OR GREAT RAGWEED.

Kinghead (Ambrosia trifida) is an annual weed belonging to the
ragweed family, which grows very rank, from 3 to 15 feet high, in
moist soil. Consequently, it is found more frequently and much
more abundantly in river valleys and in sections where the ground
hes low and where there is a good supply of moisture than in well-
drained areas or sections with a light rainfall. According to Britton
and Brown, this weed is widely distributed over the United States.
However, it seems to be a greater pest in the Northwest, especially
in Minnesota, North Dakota, and South Dakota, than in the other
Pheat_produeme States.

On account of its shape and size (fig. 1) this seed, like corn cockle,
is difficult to clean out of the wheat. One means of removing it, in

8 BULLETIN 328, U. S: DEPARTMENT OF AGRICULTURE.

addition to the regular grain-cleaning machinery commonly found
‘in mills, is that of floating it out with wheat washers, specially
devised machines for cleaning smutty wheat.. Since installing this
equipment is expensive, few mills have such facilities, and they must
depend on the ordinary grain cleaners, which remove but a small
percentage of the kinghead seed, often present in quantities as high
as 3 or 4 per cent. Unless wheat that contains large amounts of
kinghead seed is mixed with a sufficient quantity of clean wheat to
reduce the percentage of kinghead to a minimum, the flour produced
will be of inferior quality. Such flour contains black specks, which
injuriously affect the quality of the bread both in color and texture.
The writer secured in a country mill samples of flour milled from
wheat containing about 2 per cent of kinghead seed. Baking tests
of these samples showed that both the color and the texture of the
loaf were very seriously affected. When milled alone, kinghead seed

Fic. 3.~-Wheat containing 28 per cent of kinghead seed and 3.5 per cent of other foreign matter, as unloaded
from a wagon at a country elevator. (Natural size.)

gave a very low yield (less than 16 per cent) of flour, which was dark
gray in color. The flour was readily reduced, the bulk of it being
made on the break rolls and the first reduction. On account of the
dark color of this flour, a mixture of 1 per cent of kinghead seed in
wheat when milled is noticeable in the flour. When wheat con-
taining 10 per cent of kinghead was milled into three grades of flour.
the injurious effects of this so-called inseparable ingredient were in
evidence in all grades, as shown by the results of the baking tests
given in Table VI (p. 16). |

Figure 3 shows a sample of spring wheat as grown and delivered to
an elevator by a farmer. This sample contained 28 per cent of
kinghead seed by weight, in addition to 2 per cent of rye and 1.5 per >
cent of wild oats. On account of the excessive amount of this prac-
tically inseparable weed seed in the wheat, the price and grade were
greatly reduced, and, as with the sample which contained corn cockle,
a heavy dockage was assessed by the grain buyer.

MILLING AND BAKING TESTS OF WHEAT, 9
WILD VETCH.

Wild vetch (Vicia angustifolia) is a narrow-leaved species, closely
related to common vetch, and is an annual weed growing about 1 to 2
feet high in fields and waste places. The seed is nearly round, black
or dark brown in color, and, as a rule, fully as large as corn-cockle seed.
For this reason it is difficult to separate it from wheat, and when
present in appreciable quantities it lowers the grade and reduces the
price given forthe wheat. Although this weed is neither so prevalent
nor so abundant as corn cockle, yet in some localities, especially in
sections producing spring wheat, it is found in such amounts as to be
a pest. The species of wild-vetch seed found in the wheat samples
secured at country points consisted largely of the narrow-leaved
vetch and to a lesser extent the hairy-pod vetch (Vicia hirsuta). The
latter species has short pods covered with fine, short hairs (hence the

Fic. 4.—Wheat containing 3.8 per cent of wild-vetch seed and 1.5 per cent of other foreign matter, as
unloaded from a farmer’s wagon at a country elevator. (Natural size.)

name hirsuta), while the narrow-leaved vetch has black pods an inch
or more in length.

Because it was not feasible to secure a sufficient amount of wild-
vetch seed for use in the milling and baking tests which were made to
study the effects of such an impurity in wheat, hairy-vetch seed
(Vicia villosa), which is very similar.in size and shape, was substi-
tuted for wild vetch. Hairy-vetch seed is less highly colored than
seed of the wild vetch, which has a reddish orange-colored meat, and
possibly the effect on the color of the crumb of the loaf was less pro-
nounced than would have been the case if wild-vetch seed had been
used. Where 1 per cent of hairy-vetch seed is present in wheat as
ground, the flour will have a yellowish appearance and a noticeable
odor of vetch. When milled alone, hairy-vetch seed gave a flour
yield of about 58 per cent. It was hard to bolt, having a somewhat
gummy consistency. The color of the flour was similar to that of
powdered sulphur and consequently when blended with wheat flour
it imparted a yellowish tint to the bread.

Figure 4 shows a sample of spring wheat containing 3.8 per cent of
wild-vetch seed by weight, in addition to the other impurities, con-

10373°—Bull. 328—15——2

10 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE,

sisting of 0.5 per cent of wild oats and 1 per cent of pigeon grass and
other weed seed. This wheat was obtained from a farmer’s wagon
as the grain was unloaded at a country elevator. Because the grain
buyer considered wild vetch an inseparable impurity which would
injure the milling qualities of the wheat, the farmer was given a
lower price for his grain than he would have received had the wheat
been free from vetch seed.

COMPARATIVE MILLING YIELDS OF WHEAT AND OF ITS IMPURITIES.

Table III shows the yields of bran, shorts, and straight flour ob-
tained in milling wheat in comparison with the yields of these products
obtained in milling rye, corn cockle, kinghead, and hairy vetch as used
in the milling and baking tests. Averages are given of three tests with
wheat and corn cockle and of two tests with rye, kinghead, and hairy
vetch.

TaBLe III.~—Milling tests of wheat, rye, corn cockle, kinghead, and hairy vetch, showing
comparative yields of straight flour, bran, and shorts.

Straight |Quantity

Ingredient. Bran. Shorts. gua milled: Machine used in milling. color of flour.
Sees NS VS Ec SUR (eM eeace 2s 1) pe ae a
Per cent. | Per cent. | Per cent.| Pounds.

Wine ate pee a: 1285 14.7 71. 4 120 |) 50-barrel miulle=-- 22-22" te mete White.
Rayietnk So ueres 13.6 31.3 47.8 1B jal aoe Osos Sees tc RN ere ae Gray.
Corn cockle -. 22.9 28.0 47.6 20 | Small experimental mill.......-| Bluish white.
Kinghead..-- 52.3 31.9 15.8 Oiler GO. Seo BES eee ee Dark gray.
Hairy vetch.. 12.9 25.3 57.8 ‘Daas dO eee eee Yellow.

A relatively low yield of flour was secured when each impurity
was milled by itself, especially in the test with kinghead seed, from
which less than 16 per cent of flour was obtained. The presence of
more than 1 per cent of this impurity in wheat as milled resulted in
a noticeably decreased flour yield, as shown in Table IV.

Although the flour from each impurity was difficult to bolt when
milled alone, when the mixtures of rye, corn cockle, and hairy vetch
with wheat were milled the yield of flour was not greatly reduced.
In all probability the*wheat flour aided in bolting through a greater
proportion of the flour from each of the impurities. On account of
the decidedly different color of the flour of each impurity from that
of wheat flour, the detrimental effects on the color of the bread made
from such flour mixtures are very noticeable. (See Table IV.)

MILLING AND BAKING TESTS OF WHEAT CONTAINING IMPURITIES.
TESTS WITH ADMIXTURES OF VARIOUS PERCENTAGES OF EACH IMPURITY.

Table IV gives the results of millmg and baking tests with samples
of wheat containing certain percentages of the so-called inseparable :
impurities—rye, corn cockle, kinghead, and hairy-vetch seed. These
data are the averages of tests covering three years with rye, kinghead,
and corn cockle, with the exception of the tests with 5 per cent and 10

MILLING AND BAKING TESTS. OF WHEAT. Jed

per cent of corn cockle, in which instances tests were made for one year
only, and the results obtained in the experiments with hairy vetch
are the averages of tests covering two years.

TABLE IV.—Milling and baking tests of clean wheat and of wheat containing different
percentages of rye, corn cockle, kinghead, and hairy vetch.

Quantity
ae : of wheat
apes 5 Score. | required © Remarks concerning—
a ‘ Bl} # per barrel
ag S138 of flour.
Sample description. SM ce
(o)
heVS | Sele le
n H 3 os o
5 & 2 = 3 =s BE g Crumb. Dough.
iS fo) HIOL 5S
SlalelEel| > sss] a | «
P..ct|P.ct|P..ct|P..ct| C.c
Clean wheat (check). -.|12. 5)14. 7|71. 4|58.0) 2,510} 94) 96 4 34| Creamy ._.-..-
Wheat with rye: Biastic
IO" Ceialinsdcoascon 11. 9)16. 5)70. 0/57. 3} 2.410} 94} 95 4 “(0 es COs eee ;
2 TOO CAM psaeosoines 11. 9/15. 9)71. 2/57. 4; 2,430} 93) 94 4 30| Creamy gray ..|)} =
SipelGenterese ee 12. 3/16. 1|70. 7/57. 3) 2,440} 91} 93 4 37| Slightly gray -.
HO Chiscsascoose 12. 7/16. 3)70. 0)57. 3} 2,440} 90} 92 4 40° Grays Fairly elastic.
10 per cent.....-.../12. 9/16. 5/70. 0/57. 9} 2,370} 90} 92 4 40}... .. Goes Ae
Clean wheat (check). . .|11. 7/15. 4)71. 8/58. 2] 2,565) 94{ 97 4 Sal CredmMiye sees: | Elastic.
Wheat with corn cockle: P
IL Xe? CeiNlcsoodebac 14. 8/13. 6}70. 0/58. 1}-2, 500) 93) 95 d 40| Creamy gray -. } F eae
2 per cent.........- 16. 0/12. 9169. 7/57. 4| 2,470] 90/ 9o| 4| 41| Gray.......... iprairly elastic.
3) OP CM cae osonue 15. 7/12. 9/70. 4/57. 7) 2,220) 86) 87 4 38] Very gray..--- (2).
Clean wheat (check). . .|12. 8)14. 1/70. 3)62.3) 2,765) 95) 96 4 39| Creamy ......- Elastic.
Wheat with corn cockle:
[OR COW sooooseee 14, 1/15. 5}70. 1/60. 9} 1,750) 80) 82 4 40| Very gray..-.-..- (2).
lOiperkcente-- 2-222 16. 5/13. 1/69. 3/59. 4} 910) 50) 70 4 43 anes Coser |e (2)s
Clean wheat (check). . .|12.5)14. 7/71. 4/58.0) 2,510} 94! 96 4 34] Creamy......-
Wheat with kinghead: |
IL TOE COMlisdsoncosec 13. 0/15. 3)70. 2|57. 8} 2,445} 93) 88 4 39| Very gray....- |+Elastic.
AEC gone seoae 13. 9)15. 7/69. 4/57. 8) 2,450} 92) 88 4 AD in IS Oise
[Oe CN ispacdsacne 14. 3/16. 8/67. 6|57.9) 2,400} 89} 79 4 KNesece dotnseee sect
DPCINCOMbyseeee a5 14. 6)20. 2/63. 3/57. 9] 2,350) 86) 70 5 11) Dirty gray.... Ss at Part
10 per cent........- 16. 2/20. 5/61. 5157.8} 2,240| 80; 50| 5| 19/_...- doce ein “| }Pairly elastic.
Clean wheat (check)... ./11. 4/15. 5}71. 3/58. 0) 2,450) 95} 96 4 30} Creamy - __:--- Elastic.
Wheat with hairy
vetch:
leper centiase, ase 14. 1)14. 4/69. 7|57.9} 2,115} 88) 92 4 Aye a dosssst 5% (3)
BO eTy COMtsnan ane 13. 2/12. 9/71. 2/57. 8} 2,015) 83] 90 4 Sol ellOWeeeeeee. (3)
3 [OG COMP soo ocoo de 12. 8)14. 6/71. 2/58. 2} 1,940} 78) 85 4 Giileeuse dott (4)
HIG CVM eos ssesoe 12. 714. 3)70. 7/58. 8] 1,835} 69} 79 4 37| Very yellow. (°)
10 per centes2 2 -_ = 13. 4/15. 0)70. 2,56. 3} 1,605) 63) 68 4 BYiocoac Gove teceee (8)
1 Fairly elastic, irritating to hands. 4Slightly sticky and ‘‘runny;’’ odor and flavor of vetch.
2Sticky and “‘runny;”’ very irritatingtohands. Sticky and “runny;’’ odor and flavor of vetch.
3Fairly elastic; odor and flavor of vetch. 6Short and ‘‘runny;’’ strong odor and flavor of vetch.

A study of Table LV brings out the detrimental effects which the
added impurities had on the milling and baking qualities of the wheat.
For convenience of discussion the factors of importance from the
commercial standpoint may be grouped under two headings, viz,
milling quality and baking quality.

MILLING QUALITY.

The amount of flour which can be obtained from a bushel of wheat
is of prime importance to the miller, since it is the most valuable mill
product. Therefore, any impurity that reduces the yield of flour
obtained in milling wheat, or that lowers the quality of the flour, has
a direct bearing on the milling value and should receive careful con-
sideration in grading wheat.

12 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE,

The admixture of kinghead seed in wheat greatly reduced the yield
of flour, the reduction being especially evident with an increased
amount of this impurity, while the addition of different percentages
of rye, corn cockle, and hairy-vetch seed did not so materially reduce
the amount of flour obtained.

BAKING QUALITY.

One of the prime requisites of flour is that it have good baking
qualities, that is, produce a large loaf having good texture and color
of crumb, and in addition have the power of absorbing and retaining a
large amount of water. Housewives demand a flour having a white
or creamy color. Any factor, therefore, which in any way injures the
baking qualities of flour, such as reducing the size of the loaf or low-
ering the color or texture of the bread, should necessarily be consid-
ered in placing a valuation on flour and consequently on the grade of
wheat from which the flour was milled.

EFFECTS OF IMPURITIES IN WHEAT,ZON QUALITIES OF FLOUR AND BREAD.

The presence of rye in wheat has a detrimental effect on the loaf
volume, and when more than 3 per cent of this ingredient is added the
color and texture of the bread will be noticeably injured. The effects
of the addition of such impurities as corn cockle, kinghead, or vetch to
wheat are much more detrimental in character than where rye is
added, as shown in the greater reduction in the size of loaf and the
decidedly iower scores given the color and texture of the bread.

With an increased percentage of corn cockle there was a very decided
reduction in the loaf volume, with a consequent injurious effect on the
texture. In mixing the dough an irritation of the skin of the hands _
was noticed with the flour milled from wheat contaiming 3 per cent
of corn cockle, with a decided increase in the amount of the irritation
when a larger amount of corn cockle was added.

The amount of water absorbed was also considerably less in the
tests with flour from wheat containing more than 3 per cent of corn
cockle than in the check test with pure wheat flour. When more than
3 per cent of either corn cockle or vetch seed was added to the wheat
and made into flour, the dough was ‘“‘runny”’ and sticky. In the tests
with 3 per cent and 5 per cent admixtures of hairy vetch, there was
an apparent increase in the percentage of water absorption as com-
pared with the check sample. However, the remarks concerning
the effect on the dough in this connection indicate that an excessive
amount of water had been added to the flour, resulting in a “runny”’
and sticky dough. Asmaller amount of water was added to the flour
from the 10 per cent mixture of vetch in an attempt to improve the
consistency of the dough, but even then it was short and somewhat
“runny.” Astrong and disagreeable odor and flavor of vetch was very
noticeable in the bread made from flour of hairy-vetch mixtures.

MILLING AND BAKING TESTS OF WHEAT, 113)

In these tests with the different impurities described there seemed
‘to be a very close relation between the effects produced on the loaf
volume and on the texture of the crumb. Where the volume was
greatly decreased, as shown in the results of the tests with corn cockle,
a compact loaf of bread with very small pores was obtained, while in
the tests with kinghead and rye the pores were much larger and very
irregular in shape. Evidently the strength of the gluten was greatly
injured by the presence of flour from these various impurities, espe-
cially when added in considerable quantities, and corn cockle in large
amounts seemed to destroy practically all fermentation.

Figures 5 and 6 graphically illustrate the injurious effects of rye,
hairy vetch, kinghead, and corn cockle, on the milling and baking
qualities of straight flour made from wheat containing these impu-
rities. The results of the milling and baking tests in this connection
are given in Table IV, and the discussion of these results is given on
page Il. |

Plate I is a reproduction of photographs of bread baked from flour
obtained in milling samples of wheat which contained different per-
centages of rye, corn cockle, kinghead, and hairy vetch showing the
detrimental effects of these impurities upon the baking qualities of
flour.

TESTS WITH A 10 PER CENT ADMIXTURE OF EACH IMPURITY.

MILLING TESTS.

Table V gives the results of milling tests with samples of wheat
containing 10 per cent admixtures of rye, corn cockle, kinghead, and
hairy-vetch seed. These samples were milled into three grades of
flour—patent, first clear, and second clear. The addition of 10 per
cent of kinghead resulted in a great reduction in the yield of total
flour, while there was scarcely any difference in the flour yields ob-
tained from the admixtures of rye and corn cockle compared with the
check sample of clean wheat. In this experiment but one milling test
was made with each admixture and with the clean wheat. In the
test with the 10 per cent admixture of hairy vetch, where three
grades of flour were made, there was an apparent increase of 1 per cent
of total flour over that of the check sample. Previous tests with
hairy vetch indicated that this impurity had little, if any, effect on the
flour yield, and the result of this one test with a 10 per cent admixture
of hairy vetch would be within the limits of variation, especially since
in several tests with check samples of this lot of wheat, milled as
straight flour in connection with other tests made in 1913, there was
a range of 1.5 per cent in the flour yields obtained, the maximum
yield being 71 per cent.

With the exception of the test with rye, the amount of patent flour
obtained from the samples containing impurities was noticeably less

14 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE.

than in the check test with clean wheat, and the percentage of the
lower grades of flours was correspondingly increased. This fact is of
great importance in placing a valuation on wheat which contains any
considerable amount of these objectionable impurities, for a reduction
in the yield of high-grade flour that can be obtained is a financial loss
to the miller, and the grade of such wheat should be lowered according

to the percentage of admixture of the impurity.

FIELD OF STRAIGHT FLOUSP—PER CEN: FIELD OF STRAIGHT FLOUR-FPER CEVT

:
0
&
N
I
;
:
:
N
S|
N)
.
S
N
k
8
:
N)
AN)
S
Xt

AINIOUNT OF HAIER VETCH MIIKEO. WITH WHEAT —PEP CENT

Fie. 5.—Diagram showing the results of the milling and baking tests of straight flour milled from wheat

containing various percentages of rye and hairy vetch.

TaBLE V.— Milling tests of clean wheat and of wheat containing 10 per cent admixtures
of rye, corn cockle, kinghead, and hairy vetch, milled into three grades of flour.

Quantity of
wheat used

Mor Total flour made. nok Dares
Description of ure *_ |otal AGat
sample. Blige Bran. | Shorts. Agu
pering

ent. | clear.| clear. | els.

Clean wheat (check)! 14, 9 14.7 135.0) | 6985) |(6a58)) L955 4.0 4 42
With 10 per cent—
Rye te ie 14.6 | 14.6 13.8 | 69.3 | 77.2 | 18.2 4.6 4 43
Corn cockle....| 14.5 | 14.3 15.2 | 69.2°| 74.1 | 21.8 4.1 4 43
Kinghead...... 14.9 | 18.9 20.3 | 60.4 | 71.2 | 24.3 4.5 5 24
Hairy vetch....)} 15.0 | 13.7 13.3 | 70.5 | 74.8 | 22.4 2.8 4 38

Pat- | First | Second} Bush- Pounds.

Color effects on
flour.

White.

Slightly gray.!
Bluish tint and
black specks.”

Gray.3
Yellow.?

1 Most evident in second clear. 2 Very injurious to all grades. 3 Injury evident in all grades.

MILLING AND BAKING TESTS OF WHEAT. 105)

BAKING TESTS.

Table VI gives the results of baking tests with flour milled from sam-
ples of wheat containing 10 per cent admixtures of rye, corn cockle,
kinghead, and hairy vetch. These results are interesting, especially
when correlated with the milling results given in Table V. The
greatest injury of rye is seen in its effects in the second-clear
flour, where the scores for the color and texture of the crumb were
materially lowered. More second-clear flour was obtained from the
test with rye than from the tests with any of the other impurities.

FIELO OF STRAIGHT FLOUR YPER CENT 5 YIELO OF STFPAIGHT FLOUR -PER CENT

AINMIOUNT OF AINGHEARO NUXKED WITH WHEAT — PEP CENT

:
y
t
u
|
;
W
‘
S
:
S
.
8
S
N
:
0
N
Q
;
t

Fig. 6.—Diagram showing the results of the milling and baking tesis of straight flocr milled from wheat
containing various percentages of kkinghead and eorn cockle.

Corn cockle was well distributed in all three grades of flour, as shown
by the exceedingly detrimental effects for all factors given.

Even though the amount of kinghead in each grade of flour was
small, the injurious character of this impurity was especially notice-
able in the color of the crumb and the texture of the loaf.

That the flour from hairy-vetch seed was well distributed in all
three grades of flour is evidenced by the deleterious effects on volume,
color, and texture of the loaf. As in the tests where the one grade,
straight flour, was made, rye seemed to have a less injurious effect on
the baking qualities in these tests with three grades of flour than did
corn cockle, kinghead, and vetch.

16 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE.

TaBLeE VI.—Baking tests with patent, first-clear, and second-clear flour, milled from
clean wheat and from wheat containing 10 per cent admixtures of rye, corn cockle, king-
head, and hairy vetch.

1 Sticky and ‘‘runny’’; irritating to hands.
2 Short and slightly ‘‘runny’’; strong odor of vetch.
3 Short and slightly ‘‘runny’’; very strong vetch odor.
4 Short and ‘‘runny’’; very strong vetch. odor.
The comparative results of the baking tests of patent, first-clear,
and second-clear flour milled from wheat samples containing 10 per.

cent admixtures of rye, corn cockle, kinghead, and hairy vetch, as

PRET CLEAR SECOND CLEAR

AOESOPPTION oF WATER ——FEF CENT

CHE CH
ore
COCALE
AINGHEAO
e627

FOLYNIE OF LOAF — oc.

TEXTUPE OF LOAF—SCORE

ee SS
os
so
as
Tro

COoLOfF OF BSFEARO— SCORE.

Se OS,
7o
e6Eé
so
HAIER” VETCH E ss

Fic. 7.—Diagram showing the results of baking tests with patent, first-clear, and second-clear flour milled
from wheat containing 10 per cent admixtures of rye, corn cockle, kinghead, and hairy vetch.

given in Table VI, are shown diagrammatically in figure 7. The
presence of corn cockle in flour very perceptibly lessens the percentage
of water that will be absorbed, and both corn cockle and hairy vetch

Bul. 328, U. S. Dept. of Agriculture. PLATE I.

Fie. 1.—Loaves from clean wheat (a) and from wheat containing admixtures of rye: b, 1 per
cent; c, 2 per cent; d, 3 per cent; e, 5 per cent; f, 10 per cent.

Fic. 2.—Loaves from clean wheat (a) and from wheat containing admixtures of corn cockle:
b, 1 per cent; c, 2 per cent; d, 3 per cent; e, 5 per cent; /, 10 per cent.

Fig. 3.—Loaves from clean wheat (a) and from wheat containing admixtures of kinghead seed:
b, 1 per cent; c, 2 per cent; d, 3 per cent; e, 5 per cent; jf, 10 per cent.

Fic. 4.—Loaves from clean wheat (a) and from wheat containing admixtures of hairy-vetch
seed: b, 1 per cent; c, 2 per cent; d, 3 per cent; ¢, 5 per cent; 7, 10 per cent.

Cross SECTIONS OF LOAVES OF BREAD OBTAINED IN CONNECTION WITH THE MILLING AND
BAKING TESTS WITH SAMPLES OF WHEAT CONTAINING VARIOUS PERCENTAGES OF RYE,
CorRN COCKLE, KINGHEAD, AND HairY VETCH. THE RESULTS OF THESE TESTS ARE
GIVEN IN TABLE IV.

Bul. 328, U. S. Dept. of Agriculture. PLATE II.

Fic. 1.—Effects of 10 per cent admixture of rye in wheat: a, Patent flour (check); 6, patent flour
(10 per cent rye); ec, first-clear flour (check); d, first-clear flour (10 per cent rye); e, second-
clear flour (check); 7, second-clear flour (10 per cent rye).

Fic. 2.—Effects of 10 per cent admixture of corn cockle in wheat: a, Patent flour (check): 5,
patent flour (10 per cent corn cockle); e, first-clear flour (check); d, first-clear flour (10 per
cent corn cockle); e, second-clear flour (check); 7, second-clear flour (10 per cent corn cockle).

Fre. 3.—Effects of 10 per cent admixture of kinghead seed in wheat: a, Patent flour (check);
b, patent flour (10 per cent kinghead seed); ¢, first-clear flour (check): d, first-clear flour (10
per gent pine bead seed); e, second-clear flour (check); /, second-clear flour (10 per cent king-
head seed).

Fic. 4.—Effects of 10 per cent admixture of hairy-vetch seed in wheat: a, Patent flour (check):
b, patent flour (10 per cent hairy-vetch seed); c, first-clear flour (check); d, first-clear flour
(10 per cent hairy-vetch seed); ¢, second-clear flour (check); 7, second-clear flour (10 per cent
hairy-vetch seed).

Cross SECTIONS OF LOAVES OF BREAD OBTAINED IN CONNECTION WITH THE BAKING
TESTS WITH PATENT, FIRST-CLEAR, AND SECOND-CLEAR FLOuR, MILLED FROM WHEAT
CONTAINING 10 PER CENT ADMIXTURES OF RYE, CORN COCKLE, KINGHEAD, AND HAIRY
VETCH. THE RESULTS OF THESE TESTS ARE GIVEN IN TABLE VI.

“MILLING AND BAKING TESTS OF WHEAT, sb

have an especially injurious effect on the loaf volume and texture.
The color of the crumb of bread from flour that is milled from wheat
containing large amounts of corn cockle, kinghead, and vetch is prac-
tically destroyed. 3

The information given in Table VI and graphically shown in detail
in figure 7 is summarized in figure 8. The factors taken into con-
sideration in making up this illustration are the percentage of absorp-
tion of water, volume of loaf, and texture and color of loaf for patent,
first-clear, and second-clear flour milled from samples of wheat con-
taining 10 per cent admixtures of rye, kinghead, hairy vetch, and
corn cockle.

The total scores given the loaves of bread from the samples con-
taining admixtures of impurities are graphically compared with the
scores given the check sample of clean wheat, which is used as the

standard for comparison, with a
rating or score of 100.

CHE CA

In this figure the impurities are Be
arranged in the order of their
detrimental influence on the bak-
ing qualities, beginning with rye,
which, as a whole, had the least in-

jurious effects. Corn cockle is thus

shown to be a much more objec- Sk ee

MAUFRI VET CH > 7SE

tionable impurity than any of the cocne zi
others used in the tests, the score
in every instance falling far below loaf scores, showing the detrimental effects of

Fic. 8.—Diagram comparing the summarized

‘ sie 10 per cent admixtures ofrye, kinghead, hairy
that of ay of the other Impurities. vetch, and corn cockle in wheat on the baking

Plate IT is .a reproduction of qualities of patent, first-clear, and second-clear

photographs of bread baked from flour. COE On is made with the check test
with clean wheat.

patent, first-clear, and second-clear »
flour obtained in milling wheat samples containing 10 per cent
admixtures of rye, corn cockle, kinghead, and hairy vetch, and it
illustrates the deleterious effects which these impurities have on the
baking quality of flour.

TESTS WITH FLOUR BLENDS.

Tests were made with blends of wheat flour and definitely known
percentages of flour from rye, corn cockle, kinghead, and hairy-vetch
seed, for additional study of the effects of these impurities on the baking
qualities. The flour used in these tests was obtained in milling each
of the ingredients represented in Table III. The results of the baking
tests with blends of wheat flour with each of these impurities are
given in Table VII. A blend of 0.5 per cent was in every instance
injurious, the detrimental effects being most apparent in the color of

18 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE,

the bread, and with but 1.5 per cent blends the deleterious effects on
the color and texture of the bread are especially noticeable.

Blends of rye and corn-cockle flour give a grayish tinge to the
crumb, while the addition of kinghead flour results in a loaf with a
dirty lookmg crumb. Hairy-vetch blends give to the bread a yellowish
color and a strong and disagreeable flavor and odor characteristic of
vetch.

TasLe VII.—Baking tests with wheat flour blended with different percentages of flour
made from rye, corn cockle, kinghead, and hairy vetch.

Score.

Water
Sample description (flour blends). absorp- l AES
tion Texture | Color concerning crumb.
of loaf. | of crumb. |
Per cent.
Wihes Getlout (Che ks) 5 se ee ee nen ee dS. 2 93 95 | Creamy.
Wheat flour with rye flour:

O:5SPer CON (= as See 2 ae ane seereemee ae one 58. 2 90 92 | Creamy gray

OS7OTPCPiG CNG aes eS Se is Pe 58. 2 89 91 Do.

tO Per Cen Geese ee Cer eee Se eS 58. 2 88 89 Do.

1 O}PCE CON Geren ema eee ee eee cee ee 57.1 86 85 Do.
Wiheatdioun (Check) <n nance ee rs ease he 57.9 94 95 | Creamy.
Wheat flour with corn-cockle fiour: |

OS Per Cents sek toes eee eee, Se eee 57.6 93 89 | Creamy gray

OFoqecen tances meets Bee of | tye S79 91 88 Do.

HELO PEM CRtSe rece seers ese eee ee ae ae a7. 9 91 87 Do.

Ae SSD CIC CI eect see eerie ee oa eae te 07.9 89 85 Do.

Wihiea tai our CRCCK)- as sce ces ete mer etn See ea oe 57.9 95 95 | Creamy
Wheat flour with kinghead flour:

OM PER CONGE: isos 255526 see eee. kee oo 57.6 91 86 | Dirty gray.

D575 PCR CCN GASES ern ee see ee Ee 57.6 90 80 | Do.

iQ PER CONG eer e tose eee or nee eee sk 57.9 89 75 | Very dirty gray.

WED PCT CONG. 2 See ne een ee oes eS ee oe Os 57.4 84 60 | Do.
Wihlentiiloun (check) occ. cc oe eee cee ea een ae ee 57.9 92 95 | Creamy.
Wheat flour with hairy-vetch flour:

OF PCRGCNtA . cc eke ee coe cee es ese ee eee eee o7. 4 91 92 | Creamy yellow.

O: 75 PCE COR Geo Se ease ce eee eee eee 57.9 90 91 | Yellow.

tO PEMGON Gases see eee gas fe eee ese 57.6 89 90 Do.

125 Per Genie Ee a Seas 57. 6 | 86 87 | Do.

TESTS WITH WHEAT CONTAINING KINGHEAD SEED.

Table VIII gives a comparison of the results of milling and baking
tests of samples of wheat containing kinghead seed, as delivered at a
country elevator, with the results of tests of samples of the same
wheat from which the knghead was removed by hand picking. In
these tests two samples of spring wheat, one a variety known as Blue-
stem, with 3.6 per cent of kinghead, and the other a bearded spring
wheat known as Velvet Chaff, containing 4.5 per cent of kinghead
seed, were each divided into two portions. One part was then milled
with the kinghead, while from the other part the kinghead seed was
removed by hand picking and the clean wheat milled. The detri-
mental effects of the presence of this impurity in wheat are seen in
the reduced flour yield, a smaller loaf volume, and a considerably
poorer crumb texture, while the color score of the loaf is as low as
that given bread made from low-grade flour, since the crumb was

MILLING AND BAKING TESTS OF WHEAT. 19

dark gray in color. As shown in figure 9, b, the pores of the loaf are
large and very irregular in shape in the bread made from wheat con-
taining 4.5 per cent of kinghead seed when milled.

TasLE VIII.— Milling and baking tests with samples of wheat before and after the king-
head seed was removed.

Score.
Water
eine Flour Wolttm Cs |= aaa aaa | nemanksicon=
BcSeMpLION of sample. yield. Panes of loaf. Moxhuine Color cerning crumb.
of loaf. | ofcrumb.
Bluestem wheat: Per cent. | Per cent. CLO:
With 3.6 per cent of kinghead - 70. 8 62. 4 2, 365 80 60 | Dirty gray.
Free from kinghead.........-- 72. 6 62.6 2,395 84 86 | Gray.
Velvet Chaff wheat:
With 4.5 per cent of kinghead . 70. 7 61.2 2, 215 75 50 | Dirty gray.
Free from kinghead........-.- is fills @) 61. 2 2,325 90 93 | Creamy gray.

TESTS WITH WHEAT CONTAINING WILD-VETCH SEED, AS GROWN.

Table IX gives the results of milling and baking tests of two
samples of spring wheat obtaimed by the writer from farmers’ gran-
aries. Each sample contained a large amount of wild-vetch seed
and represented the
crops as grown. Two
kinds, or species, of
wild-vetch seed were
found in these sam-
ples. The bulk of the
seed was narrow-
leaved vetch (Vicia
angustifolia), and the
remainder was the
hairy-pod vetch (Vicia
hirsuta) C Fic. 9.—Loaves of bread made from wheat free from kinghead seed (a)

A comparison is and from wheat containing 4.5 per cent of kinghead seed (0).
given of the results of tests of wheat containing wild-vetch seed,
with the results of tests of the same lot of wheat from which the
vetch seed was removed by hand picking. One of the samples
contained 17.7 per cent and the other 10.3 per cent of wild-vetch
seed after being cleaned and scoured with the mill machinery.
The fact that the mill cleaners failed to remove the vetch seed
shows that this is practically an inseparable impurity. In fact,
the grain buyer for the mill in the locality where this wheat was
grown refused to purchase this wheat, which contained such a large
amount of wild-vetch seed, claiming that it could not be removed
from the grain and that it would be a risky undertaking to make
flour from such wheat. | ,

After these samples were cleaned as well as was possible with the
small milling separator and scoured twice with the scourer of the

20 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE,

North Dakota Agricultural College mill, they were thoroughly mixed
and divided into two portions. One part containing the wild-vetch
seed was then milled, while from the other part the wild-vetch seed
was removed by hand picking and the clean wheat thus obtained was
milled.

The detrimental effects of the presence of wild-vetch seed in wheat
as milled are very apparent for all factors given in the tabulation.
The injurious effects are noticeably greater in the test with the sample
of wheat containing 17.7 per cent of this impurity than in the test
with wheat in which there was 10.3 per cent of wild-vetch seed.

Fic. 10.—Loaves of bread from wheat before and after wild-vetch seed was removed: a, With 17.7 per
cent vetch seed; 0, after vetch seed was removed; c, with 10.3 per cent vetch seed; d, after vetch
seed was removed.

TaBLeE IX.— Milling and baking tests with samples of spring wheat before and after the
wild-vetch seed was removed.

Score.
D escription of sample Flour oe Volume | Remarks concern-
yield. cient! of loaf. Rextarei@oloron ing crumb.
ofloaf. crumb.
Spring wheat: Per cent. | Per cent. Cr.

With 17.7 per cent of wild 66.8 53. 2 1, 765 70 60 | Yellowish gray.
vetch. -

Free from wild vetch....-.. 68. 4 58. 2 2,509 95 97 | Creamy.

With 10.3 per cent of wild 66.5 54.4 2,050 80 75 | Yellowish gray.
vetch.

Freefrom wild vetch.......- 67.6 | 58. 5: 2,475 97 98 | Creamy.

Figure 10 is a reproduction of a photograph of the loaves of bread
baked from flour milled from samples of wheat contamimg wild-vetch
seed. The results of the tests in this connection are given in Table IX.

ANALYSES OF WHEAT, OF THE IMPURITIES, AND OF FLOUR CONTAINING
ADMIXTURES.

Samples of patent, first-clear, and second-clear flour obtained in
milling samples of wheat containing 10 per cent admixtures of rye, corn
cockle, kinghead, and hairy vetch were submitted to the Bureau of
Chemistry of the United States Department of Agriculture for chem-
ical analyses, and the results obtained are given in Table X._ A study

MILLING AND BAKING TESTS OF WHEAT. Dale

of this table brings out the following points: (1) The percentage of
ash is greater in every instance in the flour containing the impurities
than in the pure wheat flour. (2) The percentage of ether extract (fat)
of corn cockle and kinghead seed is higher than that of wheat and is
likewise greater in all three grades of flour containing these impurities
than in the flour from clean wheat. (8) The percentage of protem in
the poorer grades of flour (first and second clear) is relatively higher
in the flour containing impurities than in the flour from clean wheat,
with the exception of the first-clear flour from the 10 per cent rye
mixture. (4) The percentage of crude fiber is considerably greater in
the first-clear and second-clear flours from the admixture of corn cockle,
kinghead, and hairy vetch than in the same grade of flour from pure
wheat. (5) The acidity of the first-clear and second-clear flour from
corn-cockle seed and vetch-seed mixtures is noticeably higher than that
of the same grades of flour from the check sample of clean wheat.

The results of the chemical analyses dicate that the flour from the
different impurities was distributed to some extent in all three grades
of flour, a larger proportion in most instances going into the first-clear
and second-clear flours.

TABLE X.——Chemical analyses of wheat, rye, corn cockle, kinghead, and hairy vetch and
of patent, first-clear, and second-clear flour milled from samples cf wheat containing 10
per cent admixtures of these four impurities.

[Moisture and undetermined, including nitrogen-free extract, not given. 1]

Air-dry samples (per cent).

Description of sample. +a
Neh eer Pro- | Crude | Pento-} Invert] Su- Sey:
Pia tEaet tein. | fiber. | sans. | sugar. | crose. AcetiC.
Ail al (ios nee ro ere pae ee ae ae OY eee 1.74 1.91] 15.44 2. 62 7.10 0.14 1.88 0. 25
Oi Sis SiC SSO Raa IEE Poe a 1.97 ity | Pale) 2.38 | 10.02 13 2. 69 a2,
WONMICOCKIO I Nomina vos aa cee hin we = <3 3. 40 6.01 | 15. 44 6. 49 6. 02 32 1.58 25
iKéin ph ea dirs cece acite oes ees cele nels 2. 99 3.33 | 11.25] 44.88} 18.97 14 60 73
TAIT VA VIEL rerse saree siamese acti neieee 2. 84 -83 | 28.56 7.18 6.15 02 1b 535) 87
PATENT WHEAT FLOUR.
Wheat (Cheela) yor o 252-2 3-5). -beee nee ce . 50 1.16 | 12.88 15 2.99 18 1 12
Wheat with 10 per cent—
SSNS ee, Ges Lee Bac ts ae Re a 58 1.19 | 12.48 17 3.31 25 1.21 -12
CommycoClale ere reece eee at) 1.40 | 12.48 17 3. 67 22 1. 26 oll
iKanghead 6 7.2/2.5 sss se s'-| ba lone . 60 1.87} 13.51 17 3.35 30 Ube aly Salil
ETAT VAViCUCh Seis) eae a OM 76 1.25 | 14.88 25 3.75 . 20 1.37 27
FIRST-CLEAR WHEAT FLOUR.
Wheat (Cheek) Rae ce a ees cesar oe Oe, 1.60 | 13.91 SAL 3. 25 . 20 1.45 SUC
Wheat with 10 per cent—
JaSAy Ce) ss ee tack Te a re ema Ra 77 1.54 | 13.28 . 20 3. 87 aZAl 1.57 Siler
Wormico elles ee. see geek oxi 92 Q532n TAG 25 27 3.12 36 1. 46 25:
eta peal die ese ce ese nic eens .79 2.13 | 14.48 . 26 5. 82 30 1.44 pila
Hairy, veteh<aesa2 Soi os eee 91 1.62} 14.94 36 4.31 - 26 1. 65 soo
SECOND-CLEAR WHEAT FLOUR.
Wien; (checle) eer oy a . 80 1.86 | 13.91 23) 3.07 22 1.65 18
Wheat with 10 per cent—
LTO Sein ae rE end eee ee - 95 1.98 | 14.48 . 24 3. 86 -25 2. 55 - 22
Wormicockles co setae cmese ne vases: 1. 20 3.06 | 16.02 41 4.10 38 1.97 384
Rerriphea dee ae cls ace eee aes | 292 2.87 |} 14.88 43 3.45 34 1. 62 19
Hairy vetehi er. se 20 eee os 1.12 2.09 | 16.65 - 53 3.49 . 23 2.00 -39

1 Chemical analyses by Dr. J. A. Le Clerc, Chief ofthe Plant-Chemistry Laboratory, Bureau of Chemistry.

22 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE.

SPECIAL CLEANING DEVICES.

SPIRAL CLEANER FOR REMOVING ROUND SEEDS FROM GRAIN.

Machines especially devised for removing round seeds from grain
and screenings are advertised in various grain papers. and catalogues
of firms manufacturing grain-cleaning machinery. One machine used
to separate vetch from wheat or rye consists of an upright spiral
tube divided into several sections. The grain containing vetch is
fed into the top and follows its course down the spiral steel tubes.
The round seed travels more rapidly and finally gets into the outer
tube or section, while irregularly shaped seeds and lighter matter
move less rapidly and are discharged from the openings of the tubes
nearer the center. Such machines require very little space, no power
(being operated by gravity), and scarcely any watching. The
capacity of these machines for cleaning grain thoroughly is very
small, as only a few bushels per hour can be cleaned. They are very .
useful in separating vetch from rye or wheat where clean grain is
desired for seeding purposes, but they have insufficient capacity for
use in grain elevators or flour mills.

THE COCKLE CYLINDER.

In addition to the grain cleaners usually found in mills for pre-
paring wheat for grinding, specially constructed machines known as
cockle cylinders are frequently installed for the purpose of removing
from the grain corn-cockle seed and other foreign matter and seeds
of similar size and shape.

Although these machines are comparatively inexpensive, a con-
siderable quantity of wheat consisting of broken, small, and shriveled
kernels is taken out in removing the corn cockle. This increases the
mechanical loss that results from cleaning grain, and a portion of
the corn-cockle seed is left in wheat after being cleaned with the
cockle cylinder.

MECHANICAL ANALYSES OF CORN-COCKLE SCREENINGS.

Table XI gives the mechanical analyses of four samples of corn-
cockle screenings secured from country mills. Sample No. 73719
represents screenings removed in cleaning wheat with the cockle
cylinder. Half a pound of screenings was obtained from each bushel
of wheat cleaned. Analysis of this sample showed that but 1.3 per
cent was corn cockle and 93.6 per cent was wheat. In the other
three samples a relatively small percentage of the screenings con-
sisted of corn cockle, while a high percentage was wheat. Sample
No. 80994 represents corn-cockle screenings removed by the cleaning
machinery in general use in country mills, and the other three samples
are screenings removed from wheat with cockle cylinders. Such

MILLING AND BAKING TESTS OF WHEAT. De

screenings are not an entire loss to the miller, since he can often sell
them at a fair price for chicken or stock feeding. Corn-cockle screen-
ings are sometimes discriminated against, since it is known that corn-
cockle seed contains a poisonous substance known as saponin, or
sapotoxin, which is said to have caused trouble in instances where
screenings containing a considerable quantity of cockle have been
fed to chickens and other animals. Feeding tests have been made
by different experimenters with varying results. Some found that
young animals were more susceptible and more seriously affected
than mature ones, while other experimenters fed varying amounts
of corn-cockle seed to different kinds of animals with no apparent
symptoms of poisoning. Further experimentation along this line is
necessary before any definite conclusions can be drawn concerning
the amount of corn-cockle seed that may be fed to different classes
of animals before ill effects are produced.

TaBLE XI.— Mechanical analyses of samples of corn-cockle screenings.

Constituents (per cent).

Foreign matter. 5
5
Other grains. Weed seeds, ete. ra
m
Labora- 2
tory No. rs 3 a
® $ SD
S , = =A
\g eS a a ® of
“a 3 ; sy s o = ae 5
a = Lo} r) tov) S aes oO Ne
Bb © 3 3 8 g = S i $ els
eerie eziiemarat Se Wehbe |e | Br | rhe anes Al hreaea
3S Ss 3 PD = = =) 5 op = a a 5 fou Ie
uel eut Cue eal cali alee eel: Eco ialere iil omic
66634 5 A GD fa Gu Gy PG) || all Oa) PONE POnh a © 0 15.0 | 24.0] 76.0
TOO ee lL ce eee LT Ola LDS DONO ty 2th 2. 4c he T6iena8 lO 4 | 4.0...) 20, 4.46) 8s] 5302
TOW ES 6 4 Sf meabod Megat ole by EO), © .3 4 1.0 6))|/ 220 0 1.3} 6.4] 93.6
80994... 0 0 2 (0) 0 0 0 0 0 0 12 ae ZnO lls oul osoulerS4e0

1 T.=trace, the amount found being less than 0.1 per cent.
SUMMARY.

Wheat as grown and as marketed frequently contains certain im-
purities such as rye, kinghead (great ragweed seed), corn-cockle seed,
and wild-vetch seed.

Grain men and millers consider these impurities as inseparable, as
they are not easily removed from wheat with the cleaning ma-
chinery in general use in grain elevators and flour mills. It is claimed
that the presence of these so-called inseparable impurities in wheat
as milled injuriously affects the baking qualities of the flour. For —
this reason wheat contaiming an appreciable amount of any of these
impurities is penalized either by lowering the grade or by reducing
the price.

24 BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE.

Special experiments were made to ascertain what effects the
presence of rye, kinghead, corn cockle, or wild-vetch seed in wheat
has on milling and baking qualities.

A sufficient amount of wheat of one variety was purchased to make
all the milling tests for each year, in order to have a basis for com-
parison of all tests with the impurities. Different percentages of each
impurity were mixed with wheat samples, which were then milled
and baking tests made with the flour.

The results of these tests show that the presence of more than 2.
per cent of any of these impurities in wheat as milled has detrimental
effects on the milling and baking qualities.

The deleterious effects of rye in wheat are less pronounced than
those of corn cockle, kinghead, or vetch seed. If present in wheat
in amounts as high as 2 per cent or more, rye lowers the quality of the
bread.

Corn cockle seems to have exceedingly injurious affoct: on the
volume, color, and texture of the loaf, and when present in amounts
of 3 per cent or more reduces the percentage of water absorption of
the flour.

Kinghead in wheat in appreciable amounts materially lowers the ©
flour yield, and the detrimental effects of this impurity in the flour
are especially noticeable in the dirty color of the crumb and the
coarse, uneven texture of the bread baked from such flour.

Vetch seed in wheat will reduce the size of the loaf and give to the
bread a yellowish tinge and a disagreeable odor and flavor charac-
teristic of vetch.

Corn-cockle seed is a more objectionable impurity in wheat than
rye, kinghead, or wild vetch, since it contains a poisonous element
known as saponin, or sapotoxin, the presence of which is very unde-
sirable in flour or bread.

ADDITIONAL COPIES

OF THIS PUBLICATION MAY BE PROCURED FROM
THE SUPERINTENDENT OF DOCUMENTS
GOVERNMENT PRINTING OFFICE
WASHINGTON, D. C.

10 CENTS PER COPY
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