CHANGES IN" FRESH BEEF DURING COLD STORAGE. 91 



at least, to enzym action. In the light of present information the 

 enzym protease may be considered as the active agent. 



CoaguToMe nitrogen. — The changes that took place in this con- 

 stituent during storage consisted of fairly marked decreases, which 

 in general became larger as the storage period was lengthened. How- 

 ever, because of the irregular changes that took place in total soluble 

 nitrogen, which in turn affected the amounts of coagulable nitrogen 

 present in the meat at a given time, the full extent of the trans- 

 formation of coagulable nitrogen into noncoagulable forms is not 

 shown by the decreases in coagulable nitrogen, but is shown rather 

 by the increases in noncoagulable nitrogen. 



Noncoagulable nitrogen. — This constituent increased continuously 

 throughout the cold-storage periods employed in these experiments. 

 The average increase in the noncoagulable nitrogen in the beef stored 

 for 14 days was 1.36 per cent, while the increase in the beef stored 

 for 177 daj's was 37.39 per cent of the noncoagulable nitrogen origi- 

 nally present. In large part at least, the changes of coagulable pro- 

 tein into noncoagulable forms may be regarded as being due to the 

 action of the enzym protease. 



Proteose nitrogen. — While the relative increase in this constituent 

 during storage was large in each experiment, there was no direct 

 relation between tne length of the storage period and the increase in 

 proteose nitrogen. The average increase in this constituent during 

 14 days of storage amounted to 34.04 per cent and the increase during 

 54 days of storage amounted to 268.91 per cent of the amount initi- 

 ally present, while the increase observed in case of the quarter stored 

 for 177 days amounted to but 57.72 per cent of the proteose nitrogen 

 initially present. The proteoses are, of course, an intermediate 

 product in the autolysis of muscle proteins, and no marked accumu- 

 lation of this product during cold storage was to have been expected. 

 While in some cases the increases in the proteose content of the cold- 

 storage meat were relatively large, yet in no case did the proteose 

 nitrogen constitute any considerable proportion of the total nitrogen 

 of the meat, the maximum average percentage being 1.97 in the 

 case of carcass No. 6, which had been stored for a period of 54 days. 



Amino nitrogen. — Without exception, each quarter of beef con- 

 tained more amino nitrogen at the end of its storage period than did 

 the corresponding fresh quarter, and likewise, without exception, 

 the longer a qiiai-ter was held in storage at a gi\'en temperature the 

 greater was the i-olativo increase in this constituent. In the quarter 

 that was stored in the packing-house cooler for 54 days, however, the 

 amino nitrogen did not increase by as gi'cat an amount as did that in 

 the (juartei" held in storage iti (he bui'cau's cold-stor'age I'oorn for 42 

 days. 1'his was j)rohai)ly due to the lower storage temperature in 

 Mie first instance. 



