谷氨酰胺转氨酶对喷雾干燥蛋清粉凝胶硬度的影响
Effect of Transglutaminase on Gel Hardness of Spray Dried Egg White Powder
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摘要: 谷氨酰胺转氨酶(transglutaminase, TGase)通过交联作用,能有效提高蛋白质的性质,进而提高食品的特性。蛋清粉的凝胶性质主要由蛋清中蛋白质(egg white protein, EWP)提供。因此,本研究通过在蛋清液中添加TGase,对蛋清液进行酶处理,经喷雾干燥得到蛋清粉。将所得蛋清粉与蒸馏水以一定比例复溶后测定其凝胶强度,经单因素实验和响应面实验设计对高凝胶强度蛋清粉工艺条件进行筛选,并通过聚丙烯酰胺凝胶电泳(SDS-PAGE)初步分析TGase对蛋清粉凝胶强度影响的作用机理。研究结果表明:当酶作用pH值为7.05,酶作用温度为34.89℃,酶作用时间为85.73 min,TGase添加量为3.40 U/g蛋白质时。所得蛋清粉凝胶强度最大,为(800.365±5.237) g,比空白组提高了53.95%。通过SDS-PAGE电泳分析可得出结论:一定的TGase处理可使部分EWP发生分子内和分子间的交联,形成相对分子量较大的蛋白质分子,使蛋白质的结构更加紧密,并增加蛋白质对水分子的吸附能力,因此使蛋清粉硬度显著增强。Abstract: Glutamine transaminase(TGase) can effectively improve the properties of proteins and thus the properties of foods through cross-linking. The gel properties of egg white powder are mainly provided by protein in egg white(EWP). Therefore, in this study, by adding TGase into the egg white solution, the egg white solution was treated with enzyme, and the egg white powder was obtained through spray drying. The obtained egg white powder and distilled water were redissolved in a certain proportion to determine its gel strength. The process conditions of egg white powder with high gel strength were screened through single factor experiment and response surface experiment design. The mechanism of TGase on the gel strength of egg white powder was preliminarily analyzed by polyacrylamide gel electrophoresis(SDS-PAGE). The study results showed that when the pH value of enzyme ac-tion was 7.05, the temperature of enzyme action was 34.89 ℃, the time of enzyme action was 85.73 min, and the added amount of TGase was 3.40 U/g protein. The gel strength of egg white powder obtained was the highest,(800.365±5.237) g, which was 53.95% higher than that of the blank group. Through SDS-PAGE electrophoresis analysis, it can be concluded that certain TGase treatment can make part of EWP to cross-link intramolecular and intermolecular, forming protein molecules with relatively large molecular weight, making the structure of protein more tightly and increasing the adsorption capacity of protein to water molecules, thus significantly enhancing the hardness of egg white powder.