1. Describe the appearance of the gliadin. 2. What was the result when water was added? 3. When burned, what was the odor of the gliadin, and what does this indicate? 4. What is gliadin?
Experiment No. 29
Bread-making Test
Make a "sponge" by mixing together:
- 12 gm. sugar,
- 12 gm. yeast (compressed),
- 4 gm. salt,
- 175 cc. water (temp. 32° C.).
Let stand ½ hour at a temperature of 30° C. In a large bowl, mix with a knife or spatula 7.7 gms. of lard with 248.6 gms. of flour. Then add 160 cc. of the "sponge," or as much as is needed to make a good stiff dough, and mix thoroughly, using the spatula. With some flours as small a quantity as 150 cc. of sponge may be used. If more moisture is necessary, add H2O. Keep at temperature of 30° C. Allow the dough to stand 50 minutes to first pulling, 40 minutes to second pulling, and 30 to 50 minutes to the pan. Let it rise to top of pan and then bake for ½ hour in an oven at a temperature of 180° C. One loaf of bread is made of patent flour of known quality as a standard for comparison, and other loaves of the flours to be tested. Compare the loaves as to size (cubic contents), color, porosity, odor, taste, nature of crust, and form of loaf.
Experiment No. 30
Microscopic Examination of Yeast
On a watch glass mix thoroughly a very small piece of yeast with about 5 cc. of water and then with the stirring rod place a drop of this solution on the microscopical slide, adding a drop of very dilute methyl violet solution. Cover with the cover glass and examine under the microscope. The living active cells appear colorless while the decayed and lifeless ones are stained. Yeast cells are circular or oval in shape. (See Fig. 46.)