o. 21

Boric Acid in Meat

Cut into very small pieces 5 gms, of meat, removing all the fat
possible. Place in an evaporating dish with 20 to 25 cc. of water to
which a few drops of HCl have been added and warm slightly. Dip a piece
of turmeric paper in the meat extract and dry. A rose-red color of the
turmeric paper after drying (turned olive by a weak ammonia solution) is
indicative of boric acid.

1. How may meat be tested for boric acid? 2. Why is HCl added to the
water? 3. Why is the water containing the meat warmed slightly? 4. What
is the appearance of the turmeric paper after being dipped in the meat
extract and dried? 5. What change takes place when it is moistened with
ammonia, and why?

Experiment No. 22

Microscopic Examination of Cereal Starch Grains

Make a microscopic examination and drawings of wheat, corn, rice, and
oat starch grains, comparing them with the drawings of the different
starch grains on the chart. If the material is coarse, pulverize in a
mortar and filter through cloth. Place a drop or two of the starchy
water on the slide, cover with a cover glass, and examine.

Experiment No. 23

Identification of Commercial Cereals

Examine under the microscope two samples of cereal breakfast foods, and
by comparison with the wheat, corn, and oat starch grains previously
examined tell of what grains the breakfast foods are made and their
approximate food value.

Experiment No. 24

Granulation and Color of Flour

Arrange on glass plate, in order of color, samples of all the different
grades of flour. Note the differences in color. How do these differences
correspond with the grades of the flour? Examine the flour with a
microscope, noting any coarse or dark-colored particles of bran or dust.
Rub some of the flour between the thumb and forefinger. Note if any
granular particles can be detected.

Experiment No. 25

Capacity of Flour to absorb Water

Weigh out 15 gms. of soft wheat flour into an evaporating dish; then add
from burette a measured quantity of water sufficient to make a stiff
dough. Note the amount of water required for this purpose. Repeat the
operation, using hard wheat flour.

1. How may the absorptive power of a flour be determined? 2. To what is
it due? 3. Why do some flours absorb more water than others?

Experiment No. 26

Acidity of Flour

Weigh into a flask 20 gms. of flour and add 200 cc. distilled water.
Shake vigorously. After letting stand 30 m