CHEDDAR CHEESE RIPENING 251 



ment. These enzymes produce effects 1 closely related to, 

 if not identical with, those of pepsin in the following par- 

 ticulars : neither the rennet enzyme nor pepsin causes 

 much, if any, proteolytic change except in the presence 

 of acid; the quantitative results of proteolysis furnished 

 by the rennet enzyme and pepsin agree closely, when 

 working on the same material under comparable condi- 

 tions ; the classes of soluble nitrogen compounds formed 

 by the two enzymes are the same, both quantitatively and 

 qualitatively; neither enzyme forms any considerable 

 amount of amido compounds and neither produces any 

 ammonia; the soluble nitrogen compounds formed by 

 both enzymes are confined to the group of compounds 

 known as paranuclein, caseoses and peptones. 



Rennet exerts a digestive effect on the casein 2 which is 

 intensified by the development of acid in the curd. The 

 soluble nitrogenous products formed in Cheddar cheese 

 by the rennet enzymes are the albumoses and the higher 

 peptones. Experiments show that no flavor develops 

 until the amido acids and ammonia are formed. When 

 the rennet enzymes were the only digesting ferments in 

 the cheese, there was no trace of cheese flavor. This is 

 probably due to the fact that the rennet enzyme changed 

 the casein into caseoses and peptones but did not form 

 amido acids and ammonia. Some authorities 3 think 



1 Van Slyke, L. L., et al., Action of rennin or casein, N. Y. 

 (Geneva) Exp. Sta. Tech. Bui. 31, 1913. 



Van Slyke, L. L., et al., Cheese ripening investigations ; rennet 

 enzyme as a factor in cheese ripening, N. Y. (Geneva) Exp. 

 Sta. Bui. 233, 1903. 



2 Bosworth, A. W., Studies relating to the chemistry of milk 

 and casein, N. Y. (Geneva) Exp. Sta. Tech. Bui. 37, 1914. 



3 Wis. Exp. Sta. Kept. 1898, Distribution of galactase in 

 milk from different sources, pages 87-97. 



Wis. Exp. Sta. Kept. 1903, pages 195-197, 201-205, 222-223, 

 Action of proteolytic ferments on milk. 



