Research and Development Center, Seoul Dairy Cooperative, Ansan, Kyunggi 425-839, South Korea. Division of Food Bioscience and Technology, College of Life Science and Biotechnology, Korea University, Seoul 136-701, South Korea
J Dairy Sci. 2013 Aug;96(8):4899-911. doi: 10.3168/jds.2013-6613. Epub 2013 Jun 13.
The objective of this study was to determine the enhanced effects on the biological characteristics and antioxidant activity of milk proteins by the combination of the Maillard reaction and enzymatic hydrolysis. Maillard reaction products were obtained from milk protein preparations, such as whey protein concentrates and sodium caseinate with lactose, by heating at 55°C for 7 d in sodium phosphate buffer (pH 7.4). The Maillard reaction products, along with untreated milk proteins as controls, were hydrolyzed for 0 to 3h with commercial proteases Alcalase, Neutrase, Protamex, and Flavorzyme (Novozymes, Bagsværd, Denmark). The antioxidant activity of hydrolyzed Maillard reaction products was determined by reaction with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, their 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, and the ability to reduce ferric ions. Further characteristics were evaluated by the o-phthaldialdehyde method and sodium dodecyl sulfate-PAGE. The degree of hydrolysis gradually increased in a time-dependent manner, with the Alcalase-treated Maillard reaction products being the most highly hydrolyzed. Radical scavenging activities and reducing ability of hydrolyzed Maillard reaction products increased with increasing hydrolysis time. The combined products of enzymatic hydrolysis and Maillard reaction showed significantly greater antioxidant activity than did hydrolysates or Maillard reaction products alone. The hydrolyzed Maillard reaction products generated by Alcalase showed significantly higher antioxidant activity when compared with the other protease products and the antioxidant activity was higher for the whey protein concentrate groups than for the sodium caseinate groups. These findings indicate that Maillard reaction products, coupled with enzymatic hydrolysis, could act as potential antioxidants in the pharmaceutical, food, and dairy industries.
本研究旨在通过美拉德反应与酶解的结合，确定对牛奶蛋白的生物学特性和抗氧化活性的增强作用。美拉德反应产物是通过在 pH7.4 的磷酸钠缓冲液中于 55°C 加热乳蛋白制剂（如乳清蛋白浓缩物和乳清蛋白酸钠）7d 获得的。美拉德反应产物与未经处理的牛奶蛋白作为对照，用商业蛋白酶 Alcalase、Neutrase、Protamex 和 Flavorzyme（诺维信，丹麦 Bagsværd）在 0 至 3h 内进行水解。水解美拉德反应产物的抗氧化活性通过与 2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸）二铵盐反应、其 1,1-二苯基-2-苦基肼自由基清除活性和还原铁离子的能力来测定。进一步的特性通过邻苯二甲醛法和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳来评估。水解度随时间的推移呈逐渐增加的趋势，其中 Alcalase 处理的美拉德反应产物水解度最高。随着水解时间的增加，自由基清除活性和还原能力逐渐增加。酶解和美拉德反应的组合产物的抗氧化活性明显高于水解产物或美拉德反应产物单独的抗氧化活性。与其他蛋白酶产品相比，Alcalase 产生的水解美拉德反应产物表现出显著更高的抗氧化活性，且乳清蛋白浓缩物组的抗氧化活性高于乳清蛋白酸钠组。这些发现表明，美拉德反应产物与酶解相结合，可以作为制药、食品和乳制品行业的潜在抗氧化剂。
