ANNUAL REPORT, 1938 49 



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

 The effect of agitation of the cream aftei pasteurization on the whipping proper- 

 ties of the cream is being studied. The results seem to indicate that preliminary 

 agitation of the cream immediately after pasteurization does not improve its 

 whipping properties. A preliminary agitation period of one-half minute, at 

 70°, 85", or 100° F., decreased the rate of whipping and slightly decreased the 

 overrun, but did not affect the maximum stiffness and the amount of serum drain- 

 age from the whipped cream. 



Changes that Occur in the Storage of Frozen Sweet Cream. (H. G. Lind- 

 quist.) A few batches of cream, to which small amounts of salts (sodium citrate 

 and disodium phosphate) were added, were frozen and stored. The stored frozen 

 cream, on thawing and heating, oiled oft badly, and no beneficial results from the 

 addition of salts were noted. The project will be continued, adding salts and 

 sodium alginate before freezing the cream. 



The Use of Egg Solids in Ice Cream. (M. J. Mack.) Egg solids in some form 

 are frequently used in ice cream, and many states specify a minimum amount of 

 egg yolk solids which must be present in ice cream custards. 



Either fresh, frozen, or dehydrated egg yolk may be used. One of the principal 

 reasons for using egg yolk in ice cream is to increase the whipping ability and thus 

 decrease the freezing time for ice cream when frozen in batch freezers. Egg yolk 

 has other advantages in ice cream: it affects the flavor and color of the product, 

 increases the stability, and improves the melting appearance of the ice cream. 



A number of companies have offered for sale dehydrated egg yolk mixed or 

 "blended" with other solids, such as egg albumen, milk solids, and sugar. The 

 claim is made that these "blends" are superior to the plain dehydrated yolk. 

 The data collected thus far indicate, however, that the blended yolk may be 

 inferior to the powdered egg yolks even to a greater extent than might be ex- 

 pected from the dilution effect produced by the admixture of other solids to the 

 egg yolk. Some blended products appear to affect the rate of whipping very 

 little and to aftect adversely the melting appearance of the finished ice cream. 

 Users of blended egg yolk powders have unknowingly failed to comply with State 

 regulations for ice cream custards because of the lower egg solids content of such 

 products. 



Factors Affecting the Melting Appearance of Ice Cream. (M. J. Mack.) Ice 

 creams frequently fail to melt to a smooth, creamy liquid, and the consumer 

 may therefore assume that the product is of poor sanitary quality or that it has 

 been adulterated. Invariably the product is entirely suitable for consumption; 

 the unsatisfactory melting appearance is the result of some factor which has no 

 adverse effect on the other properties of ice cream. 



Defects which often appear in the melting appearance of ice cream are (1) 

 failure to melt, (2) a "curdy" or "feathery" appearance, and (3) exudation of milk 

 serum from the product. Previous research has shown that factors which affect 

 adversely the stability of the casein in ice cream also cause the melting appear- 

 ance to be undesirable. In this investigation a number of factors have been found 

 to affect the melting appearance which have little or no effect on the stability 

 of the casein in the product. 



The composition of ice cream has much to do with the melting appearance. 

 Variations in the butter fat content as well as in the amount of serum solids, 

 sugar, stabilizer, and egg solids all affect the melting characteristics of the product. 

 The stabilizer used is of significance in this respect as is the homogenization 

 pressure, pasteurization temperature, and rate of freezing. The purpose of this 

 investigation is to establish the effect of each of the above factors on the melting 



