ANNUAL REPORT, 1934 35 



DEPARTMENT OF DAIRY INDUSTRY 



J. H. Frandsen in Charge 



A Method for the Determination of the Relative Stiffness of Cream During 

 the Whipping Process. (W. S. Mueller.) The purpose of this study was to find a 

 simple method for measuring the relative stiffness of cream throughout the 

 whipping process and to show the importance of such measurements. It was 

 found that, by the use of a mechanical whipper and sensitive wattmeter, a con- 

 tinuous record of the stiffness of the cream throughout the whipping process 

 could be obtained by simply recording the input of the motor in watts at inter- 

 vals of ten seconds, or less if desired. It was found that this method of measuring 

 relative stiffness of cream could not be used with all mechanical whippers. The 

 wattmeter method for measuring the stiffness of cream while it is being whipped 

 should be useful in studies of cream whipping made either by the scientist or by 

 the commercial dairyman. The results of this investigation have been prepared 

 for publication in the Journal of Dairy Science. 



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

 M. J. Mack, and H. G. Lindquist.) This investigation was continued by studying 

 the effect of the following factors: 



1. Separation temperature. 



2. Standardization with various dairy products. 



3. Pasteurization temperature. 



4. Homogenization. 



5. Rate of cooling. 



6. Addition of gelatin and other stabilizers. 



7. Addition of sugar. 



In the study of these various factors the keeping quality of the whipped cream 

 received considerable attention as this is important to the dairyman selling cream 

 already whipped. Further studies are necessary before any conclusions can 

 be drawn. 



Use of Gelatin in Ice Cream Specialties. (W. S. Mueller and J. H. Frandsen.) 

 The results of this investigation have been published in The Ice Cream Trade 

 Journal for July 1934. The following summary and conclusions were made: 



1. The addition of fruit-flavored gels to ice cream specialties seems desirable 

 from the standpoint of attractiveness, palatability, and greater variety. 



2. Fruit-flavored gelatin will remain clear, even at ice cream storage tempera- 

 tures, when the correct amount and kind of sugar is used in making the gel. 



3. A gelatin-sugar mixture which contained 30 percent cane and 30 percent 

 corn sugar proved most satisfactory. 



Effect of Aging Treatment on the Bacterial Count of Ice Cream Mixes. (W. S. 



Mueller and R. L. France, Department of Bacteriology.) A report of this in- 

 vestigation has been published as Bulletin 314. 



The Effect of Aging Treatments on the Tyndall Phenomenon of Gelatin- Water 

 Solutions. (W. S. Mueller.) In this study gelatin-water solutions were subjected 

 to the same aging treatments as the ice cream mixes (as reported in Bulletin 

 302) and the effect on the Tyndall phenomenon noted. It is hoped that these 

 observations will aid in explaining the effect of the high (68°F.) initial aging 

 temperature on ice cream mixes containing gelatin. 



