ANNUAL REPORT, 1941 45 



mine whether cocoa powders commonly sold in this country contain such an 

 enzyme. In preliminary studies 25 samples of cocoa powder have been investi- 

 gated. When one percent of cocoa powder, by weight, was added to good quality 

 milk (.16 percent acidity), only one cocoa powder coagulated the milk shortly 

 after heating at 149° F. for 30 minutes. Further investigation will be made, 

 using milk of higher acidity and of a low protein stability, and also adding a larger 

 amount of cocoa to the milk. 



8. The Effect of Various Methods of Pasteurization on Chocolate Milk. (W. S. 

 Mueller and A. M. Shipley.) Further experiments in pasteurizing chocolate- 

 flavored milk by the Electropure process substantiate in a general way the results 

 of last year. However, in the latest trials, the Electropure method was more 

 efficient in the reduction of the bacteria count of highly viscous chocolate milks. 



Cooperative Study with the American Dairy Science Association Committee 

 on Methods for Determining the Curd Tension of Milk. (W. S. Mueller.) The 

 final report of the committee on methods of determining the curd tension of milk 

 was published in the Journal of Dairy Science, 24, September 1941. 



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



(VV. S. Mueller and M. J. Mack.) A major flavor defect of orange or lemon ice 

 and sherbet is the development of terpene odors and flavors, as a result of the 

 oxidation of the oil in the flavoring material. It seems logical that this flavor 

 defect could be prevented or minimized by the addition of an antioxidant. 

 Therefore, the antioxygenic effect of oat flour and of a concentrated extract of 

 oat flour was studied by adding 0.5 and 0.1 percent of these substances, respec- 

 tively, to lemon and orange ices. Fresh orange and lemon juice were used as the 

 flavoring materials. The control samples developed a harsh flavor after four 

 days, while the samples containing the antioxidants had a typical orange and 

 lemon flavor for several weeks. In the concentrations used, the concentrated 

 extract of oat flour was slightl)- more effective than the powdered oat flour. A 

 protective action was also noted when a sugar which had been treated with the 

 oat flour concentrate was added to the orange and lemon ices. 



Cocoa flour was found to be an effective antioxidant when added directlj' to 

 milk. Also cocoa flour and oat flour possessed antioxygenic properties when 

 used for treating paper milk-container stock. 



Factors which may affect the solubility of the antioxidant oat flour in ice 

 cream mix and milk are being investigated. The effect of temperature of the milk 

 at the time the oat flour is added has been studied. No significant differences 

 were noted for temperatures ranging from 50° to 160° F. 



The Use of Corn Syrup Solids in Ice Cream and Ices. (M. J. Mack and J. H. 

 Nair.) The use of dried corn s\Tup as a sweetener in frozen dairy products was 

 discussed in a previous publication. (Corn Syrup Solids Improve Frozen Dairy 

 Products. Lynn R. Glazier and Merrill J. Mack. Food Industries, June 1941, 

 p. 68.) The replacement of 20 to 25 percent of the sucrose ordinarily used in 

 ice cream by corn syrup solids was found to affect but slightly the sweetness of 

 the product and to improve somewhat the body and texture and melting charac- 

 teristics of the ice cream. Consumer acceptance of ice cream containing sucrose 

 and corn syrup solids seemed to be slightly greater than of that containing sucrose 

 as the only sweetening agent. During the first part of the study it became evident 

 that factors other than the sugar content of ice cream may affect the apparent 

 sweetness of the product. Therefore, the project is being continued to study 

 some of these factors. 



Preliminary results indicate that the apparent sweetness of ice cream may be 

 affected by such factors as the source of butterfat, the ratio of fat to serum solids, 



