Enzymes in Cheese -ripening 419 



sel, and the studies conducted independently by Jensen, 

 in Europe, demonstrated that there is another impor- 

 tant factor in cheese-ripening, that has hitherto been 

 overlooked. Babcock and Russell, and, likewise, Jen- 

 sen, showed that the rennet employed in cheese-making 

 contains pepsin. The latter, as is well known, is capable 

 of causing the digestion of protein substances. By 

 using increased quantities of rennet in the preparation 

 of cheese, the experimenters found that there was a 

 corresponding increase in the amounts of total soluble 

 nitrogen, and of albumoses and peptones formed in the 

 course of six months. Furthermore, they found that still 

 another enzyme, galactase, plays a prominent role in 

 cheese-ripening. This enzyme has its origin apparently 

 in the cow's body, for it is secreted with the milk. It 

 resembles some of the bacterial enzymes in its action 

 on protein substances and in the end products formed. 

 Unquestionably, the two enzymes are prominent in 

 cheese-ripening and are instrumental in the breaking 

 down of the complex protein substances into more 

 simple compounds. 



Additional investigations carried out in Europe, and, 

 more particularly, at the New York Experiment Sta- 

 tion, make it practically certain that the pepsin and 

 galactase are by themselves insufficient for the complete 

 ripening of cheese. In the investigations at the New 

 York station, a lot of Cheddar cheese was divided into 

 two portions, one of which was allowed to ripen under 

 normal conditions, while the other was treated with 

 chloroform so as to exclude the action of microorganisms 

 but not of the two enzymes. When examined at dif- 



