REPORT OF THE CHEMICAL DEPARTMENT. 



THE RELATION OF CARBON DIOXIDE TO 



PROTEOLYSIS IN THE RIPENING OF 



CHEDDAR CHEESE.* 



L. L. VAN SLYKE and E. B. HART. 



SUMMARY. 



1. The object of the work described in this bulletin was to ascer- 

 tain the extent to which carbon dioxide is formed in American 

 cheddar cheese during long periods of time in the process of ripen- 

 ing, and also to learn the nature of the chemical changes that give 

 rise to the production of this gas. 



2. Two cheeses were used for this study. One was entirely 

 normal ; the other was made from milk containing chloroform and 

 kept under antiseptic conditions. The investigation was continued 

 32 weeks, when a chemical study was made of the proteolytic end- 

 products. 



3. In the normal cheese, carbon dioxide was given off continu- 

 ously, though in decreasing quantities after about 20 weeks, and had 

 not ceased at the end of 32 weeks. The total amount thus produced 

 was 15.099 grams, equal to 0.5 per ct. of the fresh cheese. In the 

 chloroformed cheese, the total amount of carbon dioxide produced 

 was 0.205 gi'am, practically none being found after three weeks. 



4. In the normal cheese, the following end-products of proteolysis 



*Reprint of Bulletin No. 231. 



