2i8 Journal of Agricultural Research voi. m. no. j 



COLOR OF UNCOOKED SALTED MEATS 



To a sample of finely ground fresh beef was added 0.2 per cent of potas- 

 sium nitrate, and the material was placed in a refrigerated room at a 

 temperature of 34° F. for seven days. At the end of that period the 

 meat had a bright-red color, but gave evidences of incipient putrefac- 

 tion. On extraction with 95 per cent alcohol, a faintly red-colored 

 extract was obtained, which on spectroscopic examination showed a faint 

 band just at the right of the D line. The color of the extract quickly 

 faded. On extraction with water the sample yielded a dark-red extract, 

 which retained its color without change for several days. On spectro- 

 scopic examination the following spectrum was observed: Just at the 

 right of the D line a very heavy dark band, and a trifle to the left of the 

 E line a heavy band, but wider than and not quite so dark as the first 

 band and with less sharply defined edges. These bands correspond 

 exactly in position with those of oxyhemoglobin and NO-hemoglobin, 

 but more closely resemble the latter. 



On treatment with sodium-nitrite solution the extract changed some- 

 what in color to a reddish brown, but still showed the two absorption 

 bands noted above, and in addition showed a methemoglobin band at the 

 left of the D line. The presence of this band would indicate that the 

 extract contained some oxyhemoglobin, which on treatment with sodium 

 nitrite changed to methemoglobin. On treatment with hydrazin hydrate 

 the extract was not changed in color, and showed the following spectrum: 

 Just at the right of the D line a very heavy band; at the left of the E line 

 a somewhat lighter and wider band with less sharply defined edges. This 

 spectrum corresponds exactly with that of the original extract. 



The position of the absorption bands just noted, the fact that these 

 bands were unaffected on treatment of the extract with hydrazin hydrate, 

 and the solubility of the color in water are sufficient proof that the color 

 of the meat under examination was due to the presence of NO-hemo- 

 globin. 



The production of NO-hemoglobin in the sample of meat under exami- 

 nation is easily explained. The potassium nitrate added to the meat had 

 been reduced, either by bacterial or enzym action or by both, to potas- 

 sium nitrite, nitrous acid, and nitric oxid, with the consequent formation 

 of NO-hemoglobin. 



Samples of various uncooked meats and sausages in which saltpeter 

 had been used as one of the curative agents were obtained on the market 

 for the purpose of studying the coloring matter of these products, and the 

 following results were obtained: 



Smoked pork shoulder. — The freshly cut surface of the meat was 

 bright red in color. On extraction with water the finely ground lean 

 meat gave a dull-red colored extract, which showed the following spec- 

 trum : Just at the right of the D line a fairly heavy dark band. ■ No other 



