摘要

Chinese cantonese sausage (CCS) is famous for its exotic flavors. This paper studied the dynamic chemical changes of sausages during oven-heating by using sodium nitrite, free amino acids (FAA),.free fatty acids (FFA) and oxidation of fat as indicators. Sausages were prepared and hanged in an oven for heating, 3 h. at 50 C and then 69 h at 40 C. Samples were taken for analysis during heating. N-1-naphthylethylenediamine dihydrochloride was analysed to determine the change of sodium nitrite in the sausage and ninhydrin colorimetry was used to determine FAA concentration (counted by cysteine). The peroxide value and carbonyl value were evaluated to determine the oxidation of fat. The chromogenic rate of sausage was determined as chromogenic rate = [A(1) x 290/(A(2) x 680)] x 100%. There were three factors influencing nitrite content at different stages during the whole oven-heating process. During the first 6 h, the weight loss resulting from water evaporation mainly caused the increase of nitrite content from 10 mg/kg to 60 mg/kg. At the middle part between 6 and 50 h, nitrite content decreased from 60 mg/kg to 30 mg/kg, being consumed in the chromogenic reaction. After 50 h, the nitrite content decreased further from 30 mg/kg to 15 mg/kg as the pH value increased, which was related to the increase of precursors of flavor-forming reaction and oxygenolysis. The increase of pH did not correlate with the changes of content of FAA or FFA during the early period, which might be due to the relatively, small amount of their content and FAA also had alkalescence. After 50 h, the pH value increased sharply, which resulted from FAA and FFA turning into precursors of flavor-forming reaction. The increase in the pH value accorded with the decrease of nitrite content. The amount of peroxide value and carbonyl value kept increasing, especially at the later part of the oven heating, which was the critical formation period of flavor substances. Therefore, it was concluded that consumption of FAA and FFA and the increase of oxidation of fat resulted. in the formation of flavor substances.