FROM CHURN TO PACKAGE 129 



fat globules, Cooper, Nuttall, and Freak 1 write : " The 

 much debated question as to the presence of a mucous 

 envelope around the globules is one of considerable im- 

 portance in the problem of churnability. This envelope, 

 the membrane of Acherson, was supposed to be derived 

 from the protoplasm of the cell. It is most generally 

 accepted that no such membrane exists; yet Storch 

 (1897) conducted a series of experiments which tend to 

 show that there is such a mucous envelope ; also Sturte- 

 vant, Aberhalden and Voltz, and others assert that there 

 is a membrane." If the viscosity is broken by ripening 

 or by pasteurization, the cream will churn more easily 

 than when it is sweet or unpasteurized. 



98. Condition of milk-fat. It is generally considered 

 that the milk-fat comparatively low in volatile acids and 

 high in olein will churn more easily than the fat that is 

 rather high in these acids and low in olein, for it is softer. 

 The globules of the soft fat cohere more readily in churn- 

 ing than those of the hard fat. Therefore, it is necessary 

 to raise the churning temperature when the fat is too hard 

 to collect properly. The condition of milk-fat is affected 

 by feed, breed of the cow, her individuality, the stage of 

 her lactation period, and perhaps a few other factors. 



Influence of feed. The kind of feed that the cows 

 eat has a marked effect on the condition of the milk-fat. 

 Cottonseed products are among the feeds that most affect 

 the fat, especially in relation to churning. Smith, Wells, 

 and Ewing 2 write : " When cows were fed cottonseed 



1 Cooper, W. F., Nuttall, W. H., and Freak, G. A., The Fat 

 Globules of Milk in Relation to Churning, Jour. Agr. Sci., Vol. 4, 

 p. 154, 1911. 



2 Smith, F. H., Wells, C. A., and Ewing, P. V., The Changes in 

 Composition of Butter Fat Produced by Feeding Cottonseed 

 Oil, Ga. Exp. Sta., Bui. 122, p. 110, 1916. 



K 



