550 



COMPOSITION AND PROPERTIES OF BUTTER 



cream, of carbon dioxide and other volatile acids which are ex- 

 pelled by the heat of pasteurization, and the higher the tem- 

 perature of pasteurization the more readily do these volatile 

 acids escape. It has been noticed also by the author and others 

 that the reduction of acid due to pasteurization is much greater 

 in the case of cream that had undergone considerable fermenta- 

 tion before pasteurization, than in cream that is comparatively 

 fresh and unfermented. 



Table 77. Per Cent Acid in Butter Made from Different Por- 

 tions of the Same Cream Before and After Pasteuriza- 

 at 145 F. 20 Minutes, 165 F. Flash and 

 185 F. Flash. 



In storage the acidity of the butter increases slightly, - due 

 to the breaking down of a portion of the milk sugar as shown 

 in the following results by Hunziker, Spitzer and Mills, 1 and 



Table 78. Showing Relation of Per Cent. Lactose and Per Cent. 



Acid in Fresh and Stored Butter Made from Raw and 



Pasteurized Cream Averages of 44 Churnings. 



x Hunziker, Spitzer and Mills Pasteurization of Sour, Farm-Skimmed 

 Cream for Butter Making. Purdue Bulletin 203, 1917. 



