Chen Chun-Chi, Chen Liang-Yu, Li Wen-Tai, Chang Ken-Lin, Kuo Meng-I, Chen Chao-Jung, Hsieh Jung-Feng
Department of Biological Science and Technology, School of Life Sciences, Longyan University, Longyan 364012, China.
Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Longyan University, Longyan 364012, China.
Nanomaterials (Basel). 2021 Oct 1;11(10):2594. doi: 10.3390/nano11102594.
The effects of chymosin on the physicochemical and hydrolysis characteristics of casein micelles and individual caseins were investigated. Adding 0.03 units of chymosin/mL led to the casein micelles in skim milk coagulating after a 3 h incubation period at 30 °C. SDS-PAGE investigation showed that β-CN, κ-CN, α-CN, and a portion of β-lactoglobulin (β-LG) in the milk supernatant fraction (MSF) were precipitated into the milk pellet fraction (MPF). The mean particle size of the MSF with chymosin decreased from 254.4 nm to 179.2 nm after a 3 h incubation period. Mass spectrometry and SDS-PAGE analysis suggested that chymosin hydrolyzed individual β-CN, κ-CN, and α-CN, but not β-LG. Chymosin hydrolysis led to a decrease in the molecular weights of the hydrolyzed β-CN, κ-CN, and α-CN. Particle size analysis indicated that there was no difference in the particle size distribution of hydrolyzed β-CN and α-CN. Moreover, our outcomes demonstrated that the hydrolysis of κ-CN by chymosin occurs before that of β-CN and α-CN.
研究了凝乳酶对酪蛋白胶粒和单个酪蛋白的物理化学及水解特性的影响。在30℃下孵育3小时后，每毫升添加0.03单位凝乳酶会导致脱脂乳中的酪蛋白胶粒凝固。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）研究表明，乳清上清液部分（MSF）中的β-酪蛋白（β-CN）、κ-酪蛋白（κ-CN）、α-酪蛋白（α-CN）以及一部分β-乳球蛋白（β-LG）沉淀到乳沉淀部分（MPF）中。孵育3小时后，添加凝乳酶的MSF的平均粒径从254.4纳米降至179.2纳米。质谱和SDS-PAGE分析表明，凝乳酶可水解单个的β-CN、κ-CN和α-CN，但不能水解β-LG。凝乳酶水解导致水解后的β-CN、κ-CN和α-CN的分子量降低。粒径分析表明，水解后的β-CN和α-CN的粒径分布没有差异。此外，我们的结果表明，凝乳酶对κ-CN的水解发生在对β-CN和α-CN的水解之前。
