COMPOSITION OF ANIMAI, BODIES 371 



small, never exceeding, according to Hoffman, 2 or 3 per 

 cent. 



493. Hemoglobin, When fresh meat is soaked in cold 

 water, the solution becomes red in color on account of the 

 hemoglobin which is extracted. Hemoglobin is a pro- 

 teid which imparts the red color to the blood and is coag- 

 ulated by heat at a temperature of 128 to 132 F. 

 There is a sufficient amount of various salts in the 

 blood to dissolve some of the fibrin proteids which are 

 precipitated at a temperature of about 140 F. or 60 C. 



494. Insoluble Proteids. The larger portion of the 

 nitrogenous material of the muscles is in the form of in- 

 soluble muscular fiber. From 90 to 95 per cent, of the 

 total nitrogenous matter of fat-free lean meat is present 

 in soluble forms. In the grains, various insoluble pro- 

 teids are found and in the different meats different kinds 

 of insoluble proteids are present. Meats differ both as 

 to the kinds and proportional amounts of the several 

 proteids which they contain. 



495. Peptones. When muscular fiber is acted upon 

 by some ferments, peptones are produced. Only a small 

 amount of peptones is present in meat. When meat is in 

 cold storage to undergo the curing process before it is 

 placed upon the market, the peptonizing process takes 

 place to a slight extent. If the process is too long con- 

 tinued, ptomains, which are poisonous compounds, may 

 develop. When meat of the best quality is produced, 

 long curing is unnecessary. 



496. Keratin is an amide compound present in meat 



