42 MASS. EXPERIMENT STATION BULLETIN 369 



13.6, 12.9, and 12.5 percent respectively. When reconstituted milks were used, 

 the reduction was 16.7, 13.7, and 11.4 percent for skim milk, part skim milk, 

 and whole milk. As the butter fat content of the chocolate milk was increased, 

 the digestibility of the milk proteins tended to increase. 



In feeding experiments, white rats were able to digest 85, 71, 69, and 71 percent, 

 respectively, of the protein when the feeds contained milk powder, milk powder 

 plus 4 percent American cocoa, milk powder plus 4 percent Dutch cocoa, and 

 milk powder plus 4 percent American cocoa and 2 percent cocoa fat. The digest- 

 ibility of the milk proteins was reduced only 7 percent by the Dutch and 6 percent 

 by the American cocoa and appeared to be unaffected by the cocoa fat. 



Nutritive Value of Milk Flavored with a Water Extract of Cocoa. (W.S. Mueller.) 

 The purpose of this study is to determine whether a water extract of cocoa has 

 the same effect as cocoa powder on the nutritive value of the milk. The following 

 diets were fed to three groups of eight rats each: Plain whole milk, whole milk 

 plus 3 percent cocoa, and whole milk plus 6 percent of concentrated water ex- 

 tract of cocoa, with sugar, sodium alginate, and minerals added to all three. 

 The concentrated water extract was made from 50 grams of cocoa per 100 c. c. 

 of water, and enough was added to the milk so that the rats received the extract 

 obtained from the same amount of cocoa that was fed to the animals on the 

 cocoa powder diet. The principle of the paired feeding method was used through 

 a period of 12 weeks. Animals receiving the plain milk and the milk plus cocoa 

 extract made about equal gains in weight, which were higher than the gains made 

 by the animals receiving milk plus cocoa powder. After the animals had been on 

 test for eight weeks, the extract group was more active than the control group 

 and the cocoa powder group was the least active of the three. A decrease in the 

 volume of urine was noted for the cocoa extract group, and their urine was higher 

 in acidity than that produced by the plain milk diet. On the other hand, the 

 urine from the animals receiving cocoa powder was lower in acidity than that of 

 the control group. 



The cocoa powder used in this experiment contained 2.5 percent cacao red, 

 while the water extract of the same cocoa contained only a trace. The results 

 of this study as well as previous nutritional studies indicate a correlation between 

 the digestibility of the chocolate milk and the amount of cacao red in the chocolate 

 flavoring material. This phase of the study is being investigated further. 



Improving the Flavor and Keeping Properties of Milk and Some of Its Products. 



(W. S. Mueller and M. J. Mack.) This project deals chiefly with antioxidants 

 for milk and some of its products. The antioxidative properties of various cereal 

 flours have been described in a paper published in Food Research 4 (No. 4):401- 

 405, 1939 (Contribution 337). 



The antioxidative properties of various sugars are now being investigated. 

 Sugar itself has antioxidative properties and is also a suitable carrier for the 

 antioxidative substance obtained in extracts from oat and corn flour and other 

 materials. Results to date indicate that the antioxidative property of sugar is 

 affected to a greater extent by the refining process than by the kind of sugar. 



Cocoa was found to contain a powerful antioxidative substance which could 

 be removed in the water or alcohol extract. The concentrated extract proved 

 to be an effective antioxidant for milk when used alone or in conjunction with a 

 carrier such as skim milk powder. Decolorizing the water extract of cocoa, 

 however, removed most of its antioxidative properties. 



The addition of .05 percent of d-gluco ascorbic acid and butyl ester of tyrosine 

 prevented an oxidized flavor in susceptible milk. 



The Effect of Aging Treatments on Gelatin and Other Ice Cream Stabilizers. 



(W. S. Mueller.) An explanation for the effect produced on gelatin solution by 



