原料乳体细胞数对硬质干酪蛋白水解及风味与质构品质的影响  

Effect of Raw Milk Somatic Cell Count on Protein Hydrolysis and Flavor and Texture Quality of Hard Cheese

作　　者：穆硕 刘鑫宇 罗洁[1] 任发政[1] 李博[1] 王娜 张永祥 葛克山[1] MU Shuo;LIU Xinyu;LUO Jie;REN Fazheng;LI Bo;WANG Na;ZHANG Yongxiang;GE Keshan(Key Laboratory of Functional Dairy,Co-constructed by Ministry of Education and Beijing Government,College of Food Science and Nutritional Engineering,China Agricultural University,Beijing 100083,China;Hebei Engineering Research Center of Animal Product,Sanhe 065200,China)

机构地区：[1]中国农业大学食品科学与营养工程学院,教育部北京市共建功能乳品重点实验室,北京100083 [2]河北省畜产食品工程技术中心,河北三河065200

出　　处：《食品科学》2019年第15期64-70,共7页Food Science

基　　金：中荷奶业发展中心项目(2017R01)

摘　　要：干酪成熟过程中蛋白质的水解是风味形成的重要途径。在中国自由放养和小规模奶牛养殖仍占有一定比例,这其中的手动挤奶方式会导致原料乳中含有一定数量具有蛋白酶活性的体细胞,影响干酪成熟及风味。目前关于体细胞通过蛋白水解作用对脱脂干酪挥发性风味物质的影响尚未明确。本研究选取3种不同体细胞数的原料乳,解析体细胞的细胞组成并制作脱脂干酪,在90 d的干酪成熟期中测定干酪的蛋白酶活性、蛋白水解水平、成熟后干酪的挥发性风味物质组成及其质构特性,评价不同体细胞数、干酪的蛋白质水解程度及其对干酪风味和品质的影响。结果表明:体细胞数越高的干酪蛋白酶活性越高,αs2酪蛋白水解程度越高,对干酪风味和质构也有不同程度的影响;使用体细胞数适量增加的原料乳(10×10^4~30×10^4个/mL)有利于干酪风味的形成;中等体细胞数组中干酪特征风味物质3-羟基-2-丁酮含量最高(34.57%),是低体细胞数组含量(28.64%)的1.2倍、高体细胞数组含量(20.72%)的1.6倍;原料乳中过多体细胞(多于86×10^4个/mL)则会导致干酪过度水解并产生不良风味,高体细胞数组中检测到会引起不良风味的风味物质如辛醛、壬醛、仲辛酮、己醛。Proteolysis is an important way of flavor generation during cheese ripening. Manual milking is always applied to free-range dairy cows and small-scale dairy farms, which now still accounts for a large proportion of the total in China, and it results in retention of somatic cells(SCs) in raw milk, affecting cheese ripening and flavor. However, the effect of somatic cells on volatile flavor compounds in cheese through proteolysis has not yet been elucidated clearly. In the present study,three skim milks containing different somatic cell counts were used for cheese manufacture after being analyzed for somatic cell composition, and the changes in protease activity and proteolysis level during 90 days of ripening, as well as the volatileflavor compounds and texture of the ripened cheeses were measured. It was shown that cheese with higher somatic cell count(SCC) had higher levels of both protease activity and proteolysis of αs2-casein and that the SCC in raw milk had different influences on the volatile flavor compounds and texture of cheese. Increasing SCC in an appropriate range(10 × 10^4 to30 × 10^4 cells/m L) was favorable for the formation of cheese flavor. The amount of 3-hydroxy-2-butanone, responsible for the characteristic flavor of cheese, in the medium SCC group was the highest(34.57%), which was 1.2 and 1.6 times higher than that of the low(28.64%) and high(20.72%) SCC groups, respectively. Excessive somatic cells(more than 86 × 10^4 cells/m L)in raw milk caused excessive hydrolysis and off-flavor generation during cheese ripening. More octanal, furfural, octyl ketone, and hexanal as unfavorable cheese flavor were detected in the highest SCC group.

关 键 词：体细胞 干酪 蛋白水解 风味 

分 类 号：TS201.2[轻工技术与工程—食品科学]