36 MASS. EXPERIMENT STATION BULLETIN 327 



reduce the total amount of nitrogen absorbed. In view of these reports this 

 project was organized with the purpose of demonstrating by animal feeding 

 experiments whether the addition of cocoa to milk is harmful, beneficial, or 

 indifferent. Considerable progress has already been made in this study. 



Mineralized chocolate milk containing 1 percent cocoa had no noticeable 

 harmful effects on white rats receiving this diet for 17 weeks, while the addition 

 of 4 percent of cocoa to the milk was harmful. 



Some Factors Affecting the Properties of Whipped Cream. (W. S. 



Mueller, M. J. Mack, and H. G. Lindquist. ) In this investigation the following 

 properties of the unwhipped and whipped cream were studied: Viscosity, 

 maximum stiffness, whipping time, overrun, amount of drainage, and fat con- 

 tent of the drainage. 



A mechanical whipper of constant speed was used for whipping the cream. 

 Relative stiffness of the whipped cream was determined by measuring the in- 

 put of the whipper motor in watts at intervals of ten or five seconds throughout 

 the whipping process. The relative whippability of the creams was determined 

 by comparing the average watt increase in stiffness per second of whipping time. 



The following substances were added in varying amounts up to 0.6 percent 

 to cream before pasteurization: Kraftogen, dehydrated sodium caseinate, Dari- 

 loid, gelatin, vegetable gelatin, dehydrated egg albumin, and dehydrated egg 

 yolk. Only three of these substances — Dariloid, gelatin, and vegetable gela- 

 tin — increased the viscosity of the cream enough to be of any significance. 

 Dehydrated egg albumen and yolk, Kraftogen, Dariloid, and gelatin slightly 

 decreased whipping ability, while sodium caseinate and vegetable gelatin 

 slightly increased the whippability of the creams. All of the substances de- 

 creased the overrun, except Kraftogen and sodium caseinate, which had no 

 noticeable effect. The serum drainage from whipped cream that had stood for 

 24 hours was practically eliminated by the use of 0.4 percent Dariloid, 0.3 

 percent gelatin, or 0.4 percent vegetable gelatin, while the other substances 

 had no marked effect. All of the substances added to the cream had a tendency 

 to decrease the percentage of fat in the drainage, except the egg yolk, which 

 had no effect, and the egg albumin, which increased the loss of fat in the serum. 



The effect of amount of sugar and time of adding it was studied. The addi- 

 tion of 10 percent of sugar appeared to give sufficient sweetness to the whipped 

 cream. Before pasteurization and immediately before whipping are the least 

 desirable times for adding the sugar from the standpoint of whipping time, 

 overrun, and amount of drainage. Sugar may be added any time after the 

 first minute of whipping without any serious detrimental effects. 



Increasing the percentage of serum solids from 6.3 to 11 percent, at 1 percent 

 intervals, by the use of skim milk powder and condensed skim milk decreased 

 the whippability of the cream and had a slight tendency to decrease overrun 

 and drainage. The viscosity of the cream increased as the serum solids content 

 was raised. 



The effect of initially aging pasteurized cream for four hours at the following 

 temperatures was studied: 50°, 68°, 86°, and 104°F. As the initial aging 

 temperature was raised, the whippability of the cream decreased and the over- 

 run was variable. The amout of drainage increased only for the 86° and 104° 

 initial aging temperatures, and only the 104° temperature caused an increase 

 in viscosity. 



Reconstructed cream made by pumping butter and skim milk through a hand 

 homogenizer did not compare favorably with ordinary cream in whipping 

 ability. 



