半硬干酪成熟过程中蛋白质水解特性研究

CHARACTERISTICS OF PROTEOLYSIS OF SEMI-HARD CHEESE DURING RIPENING PERIOD

干酪成熟过程中蛋白质的水解是非常重要的反应,影响着干酪的品质。试验以3种类切达半硬干酪为原料,采用凯氏定氮和SDS-PAGE的方法测定干酪成熟期间可溶性氮(SN)含量的变化以研究其在不同的成熟阶段蛋白质的水解特性。结果表明:随着成熟时间的延长,2种使用发酵剂乳酸菌的干酪12%TCA SN含量和pH4.6醋酸盐缓冲液SN含量随成熟期延长而逐渐增加,而未使用发酵剂乳酸菌的干酪SN含量基本保持不变。通过SDS-PAGE凝胶电泳试验可知干酪中蛋白质分解产生的肽类在成熟21d后含量急剧增多且分子量范围在97.2KD以下。

The quality of cheese was effected by the proteolysis, which was very major reation during ripening period of cheese. The proteolysis characteristics of three cheddar - like semi - hard cheeses were measured by the Kjeldahl method and SDS - polyacrylamide gel electrophoresis. The result showed that both the 12% TCA solublen nitrogen and pH4.6 acetate buffer soluble nitrogen increased during ripening period in the two cheeses using starter culture ,but had no significant changes in the noculture cheese. According to the SDS - PAGE,the propertied had significant increased after 21 ripening days,and the moctdar of the propertied was below 97.2KD.