狼山鸡腌制风干成熟过程中蛋白质分解及游离氨基酸变化规律

Proteolysis and Free Amino Acid in Langshan Chicken during Curing and Air Drying Ripening

以狼山鸡为原料进行腌制风干成熟,分析测定加工过程中鸡胸肉中蛋白质分解和游离氨基酸变化情况,探究其蛋白质分解变化规律.结果表明：狼山鸡在风干成熟过程中蛋白质有显著的分解,蛋白质水解指数（proteolysis index,PI）显著降低（P＜0.05）,肌肉肌浆蛋白和肌原纤维蛋白在腌制结束后显著分解（P＜0.05）;分子质量大于85 kD的蛋白被逐渐分解,20～25 kD的小分子蛋白逐渐累积,产品风干成熟过程中游离氨基酸总量呈显著上升趋势（P＜0.05）,说明蛋白质分解形成了风味前体物质;部分游离氨基酸在风干成熟后期出现降低的趋势,说明风干成熟后期较高的温度可以促进游离氨基酸进一步转化为风味物质.

This study was undertaken to investigate the proteolysis of myofibrillar and sarcoplasmic proteins and the consequent generation of free amino acids in the breast muscle of Langshan chicken from Nantong,Jiangsu province during curing and air drying-ripening.The results showed that the proteolysis index （PI） decreased significantly （P ＜ 0.05） during the air drying-ripening process.The contents of myofibrillar and sarcoplasmic proteins in chicken breast muscle were reduced significantly at the end of curing （P ＜ 0.05）.Electrophoresis analysis showed that the proteins with a molecular weight more than 85 kD were degraded into smaller molecules （20-25 kD）.Moreover,the total amount of free amino acids indicated a significant upward trend （P ＜ 0.05）,suggesting the formation of flavour precursors from decomposed proteins.However,some free amino acids decreased at the late drying-ripening stage.This phenomenon indicates that higher temperature can promote further conversion of free amino acids into flavour precursors.