108 



5.123 per cent, and nonproteid nitrogen 0.191 per cent. The ratio of 

 nonproteid to proteid nitrogen was 1:26.8. 



If tlu'so results are compared with those obtained for the corre- 

 sponding raw meats, it will be seen that there is a marked difference 

 between the chemical composition of uncooked meats and meats 

 cooked in hot water, the analysis of the 13 samples of the correspond- 

 ing uncooked meats (])eef and veal) being as follows: Water 70.08 « per 

 cent, insolu])le proteid 15.63 per cent, soluble proteid 2.30 per cent, 

 total proteid 17.93 per cent, nitrogenous extractives 1.09 per cent, non- 

 nitrogenous 1.63 per cefit, total organic extractives 2.72 per cent, fat 

 9.65 per cent, ash 1.01 per cent, making a total of 100.67 per cent. 

 The average nitrogen values for the uncooked meats were: Total 

 nitrogen 3.219 per cent, proteid nitrogen 2.868 per cent, and nonpro- 

 teid nitrogen, 0.351 per cent. The ratio of nonproteid to proteid 

 nitrogen was 1: 8.25. 



It is evident that there is a decided decrease in water content of the 

 meat when it is boiled in water. The average amount of water in the 

 11 samples of uncooked meats was 70.08 per cent, while in the 31 

 samples cooked in hot water it was only 57.50 per cent. This corre- 

 sponds with results previously obtained in this laboratory, and all go 

 to show that there is always a loss of water when meats are cooked in 

 hot water. It follows from the above consideration that the cooked 

 meats will contain a considerable higher percentage than the raw of 

 some or all of the constituents other than water. This is especially 

 true of the insoluble proteid, which amounts to 31.57 per cent in the 

 cooked meats and to only 15.63 per cent in the uncooked meats; that 

 is to say, the percentage amount of insoluble proteid in the cooked 

 meats is slightly more than twice as great as in the raw meats. It must 

 not, however, be supposed that this greater proportion of proteid in 

 the cooked meats is due entirely to the decrease in the proportion of 

 water. Some of the increase is due to the coagulation of albumin during 

 the process of cooking which renders some soluble proteid insoluble. 



Indeed, one of the most pronounced differences in the chemical com- 

 position of cooked and uncooked meats occurs in the amount of soluble 

 albumin present. The average (juantity of soluble proteid in the 13 

 samples of- raw meat was 2.30 percent, and in the 31 samples of boiled 

 meat only 0.38 per cent. In other words, during the cooking of the 

 meat 1.92 per cent of the proteid present in the uncooked meat in a 

 soluble form was rendered insola])le by coagulation. The actual 

 nature of this change will probably ])e Ijetter understood after a study 

 of the water-free substances. In the water-free substance of the 

 cooked meats there is 76.19 per cent of the insoluble proteid, 0.88 per 

 cent of soluble proteid. and 77.07 pei- cent of total proteid. On the 

 other hand, the insoluble proteid forms 56.37 per cent, the soluble 



a In the case of water the average represents 14 samples. 



