12 STUDIES OF POULTRY. 



Chemistry Bulletin 115. Pennington reported the analysis of the fat 

 of chickens of known history, stored for four months, at the First 

 International Congress of Refrigerating Industries (Proc., vol. 2, 

 p. 252). A rise was observed in the acid value in all twelve lots 

 examined, in some cases closely agreeing with the rise reported by 

 Richardson (loc. cit.) and in other cases exceeding it. A decrease 

 in the iodin number is generally found, representing a loss of unsatu- 

 rated acids, as well as a loss in the Hehner number, which would 

 indicate a solution of acids originally insoluble. 



The question of acidity in crude fat, both fresh and cold stored, 

 has been further studied by Pennington and Hepburn, in an effort 

 to find chemical criteria by which aging food fat might be judged. 

 Incidentally, among the samples of fat examined were some from 

 cold-stored fowls of known history and carefully prepared. A rise 

 in free fatty acid was observed which, in the same lot of chickens, 

 tended to increase with the length of the storage period. 



FORMATION OF AMMONIACAL NITROGEN AT FREEZER TEMPERATURES. 



It will be recalled that Richardson (loc. cit.), in the brief state- 

 ment of his work on cold-stored poultry, asserts that change during 

 storage did not occur, because there was a uniform ammoniacal nit- 

 rogen content. In his work on beef Richardson very properly lays 

 great stress on the presence of loosely bound ammoniacal nitrogen, 

 and studies in detail several of the methods for its estimation. He 

 finally adopted boiling with magnesium oxid as the preferable course 

 to pursue. Pennington and Greenlee, 6 studying flesh decomposition, 

 repeated the work of Richardson, but without success, because it was 

 not possible to reach a point where the loosely bound nitrogen ceased 

 to be evolved, even though many distillations were made ; and because, 

 with the most exact conditions obtainable, there was a discouraging 

 discrepancy between the quantities of such nitrogen from chickens of 

 similar though not identical history. The authors therefore adapted 

 the Folin method for ammoniacal nitrogen to chicken meat, with a 

 gain in differentiation and accuracy. 



The study of dry-picked chickens, chilled for twenty-four hours at 

 32-38 F. (0 C.-3 C.), shows that the quantity of loosely bound 

 nitrogen in the flesh varies from 0.011 to 0.012 per cent of the fresh 

 substance. Similar chickens, stored for one year, showed 0.019 per 

 cent ; for two years, 0.027 per cent ; for two years, but in bad condition, 

 0.036 per cent ; for the same period of time but in excellent condition, 

 0.023 per cent. A fowl properly chilled, then kept nine days in a 



J. Amer. Chem. Soc., 1910, 32: 568-572. 

 & J. Amer. Chem. Soc., 1910, 32 : 561-568. 

 [Cir. 64] 



