COMPOSITION AND FOOD VALUE OF BUTTER 11 



8. Water. — According to Thompson, Shaw, and 

 Norton,^ the average percentage of moisture in butter is 

 13.9, and the variation is 10.13 to 20.65 per cent. Usu- 

 ally there are very few impurities in water used for 

 washing butter, so that the composition of it may be 

 considered as simply H2O. 



9. Salt. — ' The salt-content of butter is variable. 

 Thompson, Shaw, and Norton ^ show a variation from 

 .68 per cent in one sample to 5.98 per cent salt in another 

 sample. The composition of salt varies. According to 

 Woll ^ the analyses of American salts are as follows : 



Table VI 



Highest in so- 

 dium ehlorid 



Lowest in so 

 dium ehlorid 



Sodium 

 Chlorid 



99.18 

 97.79 



Calcium 

 Sulfate 



.54 



1.48 



Calcium 

 Chlorid 



.19 



.28 



Magne- 



sium 

 Chlorid 



.05 

 .08 



Insoluble 

 Matter 



.05 

 .06 



Mois- 

 ture 



.01 

 .31 



10. Curd. — The curd of modern butter contains very 

 little if any albumin, for it is taken out in the washing. 

 The curd, therefore, is largely casein. According to 

 Thompson, Shaw, and Norton,^ the curd-content of the 

 average American creamery butter is 1.18 per cent. 



1 Thompson, S. C, Shaw, R. H., and Norton, R. P., The Normal 

 Composition of American Creamery Butter, U. S. Dept. of Agri., 

 B. A. I., Bui. 149, pp. 10-31, 1912. 



2 Woll, P. W., A Study of Dairy Salt, Univ. of Wis. Agri. Exp. 

 Sta., Bui. 74, p. 14, 1899. 



3 Thompson, S. C, Shaw, R. H., and Norton, R. P., The 

 Normal Composition of American Creamery Butter, U. S. Dept. 

 of Agri., B. A. I., Bui. 149, p. 10, 1912. 



