OF PASTEURIZATION 221 



The decrease in moisture is in all probability due to the 

 more contracted and dry condition of constituents, which in this 

 condition tend to diminish their power to hold water. 



The difference in curd content between the raw cream and 

 the pasteurized cream butter is very slight. The curd content 

 of butter made from sour pasteurized cream is usually from 

 .1 to .5 per cent lower than in raw cream butter. The very 

 slight difference shown in the table is in all probability due to 

 the fact that all the butter was washed thoroughly with two 

 washings of water and that the removal of the buttermilk was 

 facilitated by the relatively small churnings. 



The acid content of the butter in above table is unusually 

 low and this again suggests that the butter was washed thor- 

 oughly. Generally butter contains from about .1 to .3 per cent 

 acid, as shown in the averages of 44 churnings of sour cream 

 tabulated below. 



Table 41. Acidity of Butter Made from Raw and Pasteurized 

 Cream. Averages of 44 Churnings. 



Pasteurization tends to lower the acidity of the cream and 

 butter. The decrease usually averages about .05 per cent, but may 

 be greater. It is greater in the flash process than in the holding 

 process of pasteurization. The lowering of the acidity due to 

 pasteurization may be explained to be caused by the expulsion 

 by heat of carbon dioxide and other volatile acids which may 

 be present in the cream, and the higher the temperature of 

 pasteurization, the more complete is this expulsion and there- 

 fore the greater the decrease of the per cent acid in pasteur- 

 ized cream butter. 



The influence of pasteurization to reduce the acidity in 

 cream and butter must of necessity largely depend on the con- 

 dition of the cream. The carbon dioxide and other volatile 

 acids present are, in the main, products of fermentation. They 



