单 位：
甘肃农业大学食品科学与工程学院甘肃省功能乳品工程实验室
关键词：
牦牛乳硬质干酪;酪蛋白降解;尿素聚丙烯酰胺凝胶电泳;苦味;主成分分析
摘 要：
针对牦牛乳硬质干酪的苦味缺陷,分别以小牛皱胃酶、微生物凝乳酶和木瓜蛋白酶制作的牦牛乳硬质干酪为研究对象,利用尿素聚丙烯酰胺凝胶电泳,研究牦牛乳硬质干酪pH 4.6水不溶性酪蛋白的降解程度,且对成熟过程中的牦牛乳硬质干酪苦味进行感官评价,探究牦牛乳硬质干酪pH 4.6水不溶性酪蛋白降解对其苦味的影响。结果表明:牦牛乳硬质干酪在成熟期间酪蛋白发生了明显的降解,且α-酪蛋白均比β-酪蛋白降解速率快。经尿素聚丙烯酰胺凝胶电泳分离后,发现木瓜蛋白酶制作的牦牛乳硬质干酪pH 4.6水不溶性酪蛋白在Pre-α_s-酪蛋白区域有较强的蛋白带。木瓜蛋白酶制作的牦牛乳硬质干酪pH 4.6水不溶性酪蛋白中α_s-酪蛋白和β-酪蛋白降解程度均显著或极显著高于微生物凝乳酶和小牛皱胃酶制作的牦牛乳硬质干酪(P<0.05或P<0.01),木瓜蛋白酶制作的牦牛乳硬质干酪的苦味值极显著高于微生物凝乳酶和小牛皱胃酶制作的牦牛乳硬质干酪的苦味值(P<0.01),通过主成分分析得出3种凝乳酶制作牦牛乳硬质干酪的苦味值和未降解β-酪蛋白和α_s-酪蛋白含量成极显著负相关。这为控制牦牛乳硬质干酪品质提供了理论参考。
译 名：
Effect of Casein Degradation on Bitterness of Hard Yak Milk Cheese
作 者：
WANG Ling;LIANG Qi;SONG Xuemei;ZHANG Yan;Functional Dairy Product Engineering Laboratory of Gansu,College of Food Science and Engineering,Gansu Agricultural University;
关键词：
hard yak milk cheese;;casein degradation;;urea-polyacrylamide gel electrophoresis(urea-PAGE);;bitterness;;principal component analysis
摘 要：
In view of the bitter taste defect in hard yak milk cheese,calf rennet,microbial rennet and papain were used to prepare yak milk hard cheese in the present study to explore the degradation degree of pH 4.6 water-insoluble casein of hard yak milk cheese,as evaluated by urea-polyacrylamide gel electrophoresis(urea-PAGE) and sensory evaluation of bitterness during the ripening period,as well as explore the effect of degradation degree of pH 4.6 water-insoluble casein on bitterness of hard yak milk cheese.The results indicated that hard yak milk cheese casein revealed significant degradation during the ripening period;moreover,α_s-casein underwent much more extensive and faster degradation than β-casein.The pH 4.6water-insoluble casein of hard yak milk cheese made with papain showed higher intensity bands in the Pre-α_s-casein region as shown by urea-PAGE,while the degradation degree of α_s-casein and β-casem was significantly higher than that of pH 4.6water-insoluble casein from hard yak milk cheeses prepared with microbial rennet and calf rennet(P < 0.05).The bitterness of hard yak milk cheese prepared with papain was significantly higher than that obtained from microbial rennet and calf rennet(P < 0.01).These results suggested that the contents of residual α_s-casein and β-casem showed a highly significant negative correlation with bitterness for three yak milk hard cheeses by principal component analysis.This investigation can provided a theoretical basis for the quality control of hard yak milk cheese.
