University of Minnesota, Department of Food Science and Nutrition, St. Paul 55108, USA.
J Dairy Sci. 2010 Nov;93(11):4999-5009. doi: 10.3168/jds.2010-3122.
Plasmin is by far the predominant and most completely studied endogenous protease in bovine milk. Plasmin-induced proteolysis can have either beneficial or detrimental effects on the texture and flavor of dairy products, depending on the extent of hydrolysis and type of dairy product. In cheese, the breakdown of protein can help develop desirable flavors and texture during ripening, whereas in pasteurized milk and ultra-high-temperature milk, proteolysis causes undesirable gelation. Plasmin is part of a complex protease-protease inhibitor system in milk that consists of active and inactive forms of the enzyme, activators, and inhibitors. Considerable research has been done to isolate and characterize components of the plasmin system, determine how they interact, develop and compare quantitation methods, and determine how they are affected by cow characteristics, processing conditions, other milk components, storage conditions, and bacterial proteases. Considerable research has focused on enhancing or minimizing the activity of plasmin system components. The intent has been to control protease activity in casein and whey fractions, depending on the final food or ingredient application. Controlling the activity of plasmin has a great potential to improve dairy product quality and reduce their processing costs.
纤溶酶是迄今为止在牛乳中含量最丰富、研究最透彻的内源性蛋白酶。纤溶酶诱导的蛋白水解作用对乳制品的质地和风味可能产生有益或有害的影响，这取决于水解的程度和乳制品的类型。在奶酪中，蛋白质的分解有助于在成熟过程中形成理想的风味和质地，而在巴氏杀菌奶和超高温奶中，蛋白水解会导致不希望出现的胶凝。纤溶酶是乳中复杂蛋白酶-蛋白酶抑制剂系统的一部分，该系统包含酶的活性和非活性形式、激活剂和抑制剂。已经进行了大量的研究来分离和表征纤溶系统的成分，确定它们如何相互作用，开发和比较定量方法，并确定它们如何受到奶牛特性、加工条件、其他乳成分、储存条件和细菌蛋白酶的影响。大量的研究集中在增强或最小化纤溶系统成分的活性上。其目的是根据最终食品或成分的应用来控制酪蛋白和乳清部分的蛋白酶活性。控制纤溶酶的活性具有极大的潜力来提高乳制品的质量并降低其加工成本。
