成熟温度对牦牛乳硬质干酪中乳酸菌自溶及氨肽酶活性的影响  

Effect of ripening temperature on the autolysis and aminopeptidase activity of Lactococcus lactis in hard cheese from Yak milk

作　　者：宋雪梅[1,2] 张炎[1,2] 张卫兵[1,2] 梁琪[1,2] 

机构地区：[1]甘肃农业大学食品科学与工程学院,甘肃兰州730070 [2]甘肃省功能乳品实验室,甘肃兰州730070

出　　处：《食品与发酵工业》2016年第5期38-43,共6页Food and Fermentation Industries

基　　金：国家自然科学基金资助项目(31260383)

摘　　要：通过动态监测5、10、15℃成熟牦牛乳硬质干酪在1~6个月成熟过程中乳酸菌总数、乳酸脱氢酶和氨肽酶活性等变化,探究提高成熟温度对其乳酸菌自溶和氨肽酶活性的影响。研究结果表明：成熟温度对p H值影响显著（P〈0.05）。干酪中乳酸菌在1~6个月成熟过程中其数量呈现降低趋势。p H值与乳酸菌总数之间存在负相关性。5、10、15℃成熟干酪中乳酸脱氢酶活力依次呈现增加趋势,15、10℃成熟干酪中氨肽酶活性高于5℃成熟干酪中氨肽酶活性。因此,15℃成熟干酪中乳酸菌自溶程度最强,其次为10℃成熟干酪,5℃成熟干酪中乳酸菌自溶程度最弱。15℃成熟干酪中广谱性氨肽酶（broad-specificity aminopeptidase,Pep N）和脯氨酸氨肽酶（X-prolyl-dipeptidlylaminopeptidase,Pep X）活性分别是10℃成熟干酪中Pep N和Pep X活性的2.19和2.64倍。5℃成熟干酪中Pep N、Pep X活性较低,分别没有超过0.29 U/g和0.4 U/g。Contains A large array of enzymes which involved in the production of flavor compounds and texture during cheese ripening are released from Lactococcus lactis intracellular milieu after bacterial lysis. Therefore,autolysis is considered to be highly important during cheese ripening. The aim of this work was to assess the effect of ripening temperature on the autolysis and aminopeptidase activity of Lactococcus lactis in hard cheese from Yak milk by determining starter counts and the activities of lactate dehydrogenase,general aminopeptidase,and X-prolyl-dipeptidlyl aminopeptidase in the hard cheese ripened at 5,10 and 15 ℃ for 1,2,3,4,5 and 6 months. p H value was significantly affected by the ripening temperature（ P〈 0. 05）. Lactic acid bacteria counts showed decreasing trend during the ripening of 6 months. Significant negative correlation was found between p H value and lactic acid bacteria counts.The activities of lactate dehydrogenase,general aminopeptidase,and X-prolyl-dipeptidlyl aminopeptidase in the hard cheese from Yak milk ripened at 10 and 15 ℃ were higher than those in the hard cheese ripened at 5 ℃. Lactic acid bacteria in the cheese ripened at 15 ℃ showed high autolytic activity,whereas those in the cheese ripened at 10 ℃and 5 ℃ showed medium and low autolytic activity. The Pep N activity and Pep X activity in the cheese ripened at 15℃ were respectively 2. 19 and 2. 64 times of those in the cheese ripened at 10 ℃,respectively. Pep N and Pep X were low in the cheese ripened at 5 ℃ and their activity was never higher than 0. 29 U / g and 0. 4 U / g.

关 键 词：牦牛乳 硬质干酪 自溶 乳酸脱氢酶 氨肽酶 

分 类 号：TS252.53[轻工技术与工程—农产品加工及贮藏工程]