Determining the Per Cent of Skin in Beans
Place in an evaporating dish 10 gm. of beans, 50 cc. of water, and ½ gm. of baking soda. Boil 10 minutes or until the skins are loosened, then drain off the water. Add cold water and rub the beans together till the skins slip off. Collect the skins, place on a watch glass and dry in the water oven for ½ hour. Weigh the dried skins and calculate the per cent of "skin."
1. What does the soda do? 2. What effect would hard limewater have upon the skins? 3. How does removal of skins affect food value of beans and digestibility?
Experiment No. 15
Extraction of Fat from Peanuts
Shell three or four peanuts and with the mortar and pestle break them into small pieces. Place in a test tube and pour over them about 10 cc. of ether. Cork the test tube and allow it to stand 30 minutes, shaking occasionally. Filter on to a watch glass and let stand until the ether evaporates, and then observe the fat.
1. What is the appearance of the peanut fat? 2. What is the solvent of the fat? 3. What becomes of the ether? 4. Why should the peanuts be broken into small pieces?
Experiment No. 16
Microscopic Examination of Milk
Place a drop of milk on a microscopical slide and cover with cover glass. Examine the milk to detect impurities, as dust, hair, refuse, etc. Make drawings of any foreign matter present.