Food Values 357 



To Test Foods for Starch. Boil a small amount of cornstarch 

 in water in a test tube, and then add a few drops of iodine. 

 Observe what happens and state your conclusion. Boil other 

 nutrients in the same manner, add drops of iodine, and state 

 conclusions. 



To Test for Grape Sugar. Boil a few grapes in water in a 

 test tube, or boil grape sugar in solution in a test tube. Into this 

 tube pour some Fehling's solution. Observe what happens and 

 state your conclusion. Boil other food substances, treat them 

 in the same manner, and state conclusions. 



To Test for Protein. Boil a small amount of white of egg 

 in water in a test tube, shake the solution and add a few drops 

 of nitric acid, noting the change in color; then add a few drops 

 of ammonia and note the further change. State your conclusion. 

 Test other food substances in the same manner and state con- 

 clusions. 



To Test for Fats and Oils. Put a drop of olive oil on a sheet 

 of paper and leave it in a warm place. After a few minutes hold 

 the paper before the light. Note what has happened and state 

 your conclusion. Test other nutrients in the same manner and 

 state your conclusions. 



To Test for Water. Hold a piece of cold glass over a test 

 tube containing boiling water and notice that water vapor forms 

 on the glass. Heat in a dry test tube a small piece of animal or 

 vegetable food you desire to test for water and hold a piece of 

 cold glass over it. Observe what occurs and state your conclusion. 



To Test for Mineral Matter. Burn the food to be tested in 

 an iron spoon. Observe what remains in the spoon after the 

 substance has thoroughly burned and state your conclusion. 



To Test for an Acid or Alkaline Substance. Some people suf- 

 fering from an acid condition of the stomach must avoid acid 

 foods and eat more alkaline foods. Litmus paper enables one to 

 test foods for acids or alkalis. Acid substances will turn blue 

 litmus paper red. Alkaline substances will turn red litmus paper 

 blue. 



Importance of Water. The importance of a supply of 

 water, free from impurities of a harmful nature, cannot be 



