Dec. IS, J9I4 Coloring Matter of Salted Meats 221 



at the right of the D line had as their coloring matter NO-hemoglobin. 

 In the case of those samples giving a red-colored extract with alcohol 

 and showing an absorption band at the right of the D line but giving 

 no red-colored extract with water, the coloring matter of the meat was 

 not NO-hemoglobin, but a derivative of that compound. In the case 

 of those samples which gave red-colored extracts with both alcohol and 

 water and which showed an absorption band just at the right of the D 

 line, the cqlor is certainly due, in part at least, to NO-hemoglobin, and 

 it may be due, in part, to a derivative of NO-hemoglobin present as such 

 in the meat, or the alcohol may break down the NO-hemoglobin during 

 extraction. 



The evidence is ample to show that the action of saltpeter in the 

 curing of meats is primarily to cause the formation of NO-hemoglobin; 

 but it is very possible that under certain conditions of manufacture 

 or processing to which salted meats are subject, the NO-hemoglobin 

 may undergo changes. 



RED COLOR OF COOKED SALTED MEATS 



Haldane has shown that the red color of cooked salted meats is due 

 to the presence of NO-hemochromogen, a reduction product of NO- 

 hemoglobin to which the color of uncooked salted meats is due. NO- 

 hemochromogen is characterized by its solubility in alcohol, its resistance 

 to the action of reducing agents, and by a spectrum showing a distinct 

 band just at the right of the D line and a faint band a trifle to the left 

 of the E line. While Haldane's work seems to show clearly that the 

 color of cooked salted meats is due to NO-hemjjthromogen, it has seemed 

 desirable to study the subject further and to determine especially if the 

 NO-hemoglobin of uncooked meats be reduced to NO-hemochromogen 

 under other conditions than by cooking. The fact that in the examina- 

 tion of certain uncooked salted meats a coloring matter had been obtained 

 similar to NO-hemoglobin yet not possessing all of the properties of that 

 compound, as has already been noted, led the writer to believe that the 

 coloring matter of some uncooked salted meats might be due, in part at 

 least, to NO-hemochromogen. 



NO-hemochromogen is but briefly mentioned in the literature. The 

 compound is described by Linossier (1887), Haldane (1901), and by 

 Abderhalden (191 1). 



The following experiments in the production of this compound were 

 conducted by the writer. A dilute alcoholic, ammoniacal solution of 

 hematin was saturated, first with hydrogen to remove air, then with 

 nitric oxid, and finally again with hydrogen. On treatment with nitric 

 oxid the brown color of the solution gradually changed to reddish brown; 

 the characteristic spectrum of alkaline hematin disappeared, and in its 

 place appeared a spectrum showing a fairly heavy band just at the right 



