338 SCIENCE AND PRACTICE OF CHEESE-MAKING 



various conditions employed. Each analysis rep- 

 resents the average of the results obtained with 24 

 different cheeses. 



It is noticeable that all of the soluble forms of 

 nitrogen compounds increase in amount; while 

 some increase continuously, like amino acids and 

 ammonia, others increase for some months and 

 then decrease, as paranuclein, caseoses, and pep- 

 tones. Taking the total water-soluble forms in the 

 cheese at the end of 18 months, we see that, of the 

 total amount (47.25 per cent), 45.4 per cent was 

 formed in the first six weeks, 65.5 ' per cent in the 

 first 3 months, 76.5 per cent in the first 6 months, 

 and 92 per cent in the first 9 months, which is one-half 

 the entire period covered by our study. In gen- 

 eral, it is seen that, under uniform conditions, (i) 

 the formation of water-soluble proteins and protein 

 derivatives increases as cheese ages; (2) the rate of 

 formation of such compounds is more rapid in the 

 early stages of ripening, steadily diminishing with 

 ^S^'y (3) about two-thirds of these compounds are 

 formed in the first 3 months and over 90 per cent in 

 the first 9 months. 



Temperature and cheese-ripening. — In general, 

 we find in every individual cheese that temperature 

 exerts a marked influence upon the changes taking 

 place in the proteins. The effect of temperature 

 is, of course, modified by other conditions. As il- 

 lustrative of the effect of temperature, we give in 

 the table following averages in which each analysis 

 embodies the analytical results furnished by four 

 different cheeses ripened at the same temperatures. 



