26 MASS. EXPERIMENT STATION BULLETIN 305 



depended largely" on the human e\e, which at best is never exact. A new Tyndall- 

 meter, using photo-electric cells, is being developed in order to attain greater 

 accuracN'. 



Stabilizers for High Fat Ice Cream. (W. S. Mueller.) During the past few 

 \ears a number of ice cream manufacturers have been selling an ice cream high 

 in fat (16-24 per cent). This brings up a new problem; namely, what is the 

 best stabilizer for this new product? Very little experimental work has been 

 reported on the stabilization of high fat ice cream. The purpose of this study 

 is to determine the amount of gelatin needed for high fat ice cream, and also to 

 determine the advantages and limitations of the following proposed gelatin sub- 

 stitutes as a high fat ice cream stabilizer: Krabyn, Hygell, Yelkin, Kelco-gel, 

 Lakoe, Galagum, and Pectin. Some of these proposed stabilizers will also be 

 used in conjunction with gelatin. 



A chemical analysis of the stabilizers to be used in this study has been made 

 bv E. B. Holland, Department of Plant and Animal Chemistry. Studies on the 

 effect of these various stabilizers on the quality of the ice cream have not pro- 

 gressed sufficiently to make possible definite conclusions. 



The Effect of Aging temperature on the Bacteria! Count of the Ice Cream Mix. 



(W. S. Mueller and R. L. France.) This research has shown definitely that a 

 pasteurized ice cream mix may be aged for six hours at 68° F. with no significant 

 increase in bacterial count. Indications are that a mix may even be held 10 

 hours at 68° F. with no significant increase in bacteria! count. These results 

 are contradictory to a general beiief in the ice cream industry that a pasteurized 

 ice cream mix must be cooled to approximately 40° F. immediately after homogeni- 

 zation in order to avoid marked increases in bacterial growth. Probable reasons 

 for this lag in bacterial growth are being studied. 



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

 M. J. Mack, and H. G. Lindquist.) The purpose of this project is to study 

 factors, either neglected or inadequately studied in previous research, which 

 affect the whipping of cream and the stability of the finished product. 



Some previous studies on whipping cream are open to criticism because man- 

 ually operated wh'ppers were used which prevented whipping under standard 

 conditions to a given degree of stiffness. In this investigation a mechanical 

 whipper has been connected with a sensitive wattmeter so that the whipping 

 process can be carefully studied and controlled. Preliminary trials with this 

 method have shown that both the rate of whipping and the stiffness of the whipped 

 cream can be measured at any time in the process with considerable exactness. 

 A method of this type should be used in the control laboratory as well as for 

 research since minor differences, often overlooked in hand whipping, are easily 

 detected with a mechanical whipper which has a constant speed. 



Preliminary studies have been made on the following factors: 



1. Effect of percentage of fat. 



2. Effect of temperature. 



3. Effect of aging. 



4. Effect of delated cooling. 



A Study of Ice Creams High in Fat Content. (AI. J. Mack.) A tendency 

 towards the manufacture of richer ice cream has been evident in New England 

 for several years. Keen competition within the industry, coupled with lower 

 ingredient costs, undoubtedly are factors which have an important bearing on the 

 increased use of richer ice creams. 



