CHANGES IN FRESH BEEP 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. 
Coagulable 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 days 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 quarter was held in storage at a given temperature the 
greater was the relative 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 great an amount as did that in 
the quarter held in storage in the bureau's cold-storage room for 42 
days. This was probably due to the lower storage temperature in 
the first instance. 
