酸肉发酵中蛋白质降解及影响因素的研究

Study on Protein Degradation and Its Affecting Factors in Fermentation Process of Sour Meat

目的:了解蛋白质降解与酸肉品质间的关系以指导合理消费。方法:分析酸肉在发酵过程中主要环境因素、乳酸菌数及蛋白质降解产物的变化。结果:总蛋白质、肌原纤维蛋白和肌浆蛋白随发酵时间延长逐渐下降,非蛋白氮逐渐增加;蛋白质降解中间产物多肽氮及氨态氮呈先升后降趋势,发酵60d时挥发性盐基氮为19.56g/100g;氨基酸组成分析显示,发酵可提高蛋白质氨基酸分;相关性分析显示总蛋白质、肌原纤维蛋白和肌浆蛋白含量变化与乳酸菌数和氯化钠含量变化呈显著负相关,而与水分活度和pH值呈显著正相关;非蛋白氮与乳酸菌数和氯化钠含量显著正相关,而与水分活度和pH值显著负相关。结论:发酵可提高酸肉蛋白质营养价值,综合安全及风味因素,建议酸肉发酵时间在20～40d为宜。

The relationship between protein degradation and quality of fermented sour meat was investigated by analyzing the environmental factors, the lactic acid bacteria number and the degraded products of protein in sour meat during fermentation. The results indicated with the increasing fermentation time, the contents of protein, myofibril protein and myosinogen reduce while the content of non-protein nitrogen （NPN） increases. The intermediate products of protein degradation including peptide nitrogen and amino acid nitrogen increase at first and then fall down. The content of total volatile basic nitrogen is 19.56 g/100 g sour meat fermented for 60 d. Analysis on amino acid composition showed that the amino acid score increases during fermentation. The contents of protein, myofibril protein and myosinogen are conversely linked to lactic acid bacteria number or NaCl content, but positively to activity of water （Aw） or pH value. However, the changes of NPN show a different pattern and positively related to the lactic acid bacteria number or NaCl content, but negatively related to Aw or pH value. In this regard, the nutritive value of protein in sour meat can be improved by fermentation and the best fermented time of sour meat is suggested to be between 20 d and 40 d when considering safety and flavour of sour meat.