24 



FOOD MATERIALS AND HOW TO DETECT THEM 



Method. (a) Put a few crystals of cane sugar into a 

 test tube and add concentrated hydrochloric acid to the depth 

 of | inch. Heat the mixture and notice the change of 

 color. 



(6) Place a raisin, a fig, or a small piece of glucose in water 

 in a test tube and dissolve the sugar by shaking the mixture. 



Cane sugar. Test. 



Hydrochloric 

 acid. 



Grape sugar. Test. 



Fehling's 

 solution. 



FIG. 6. 



To a little of this solution add a drop of Fehling's solution 

 or Benedict's solution and heat it. What change occurs ? 



Conclusion. In two sentences state the test for these 

 two kinds of sugar. 



Suggestion. Test molasses and candies and find out 

 which contain cane sugar and which contain grape sugar. 



Test starch for grape sugar. Result? Test saliva for 

 grape sugar. Result ? Place starch paste and saliva in a test 

 tube and set it aside in warm place for \ hour. Then test the 

 mixture for grape sugar. Result? What does this indicate 

 as to the action of saliva in digesting starch in food? 



