College of Food Science and Engineering, Northwest A&F University, Yangling 712100, China.
J Dairy Sci. 2013 Jul;96(7):4242-51. doi: 10.3168/jds.2012-6511. Epub 2013 May 16.
The present research described the preparation, purification, and identification of antioxidant peptides from goat milk casein (GMC). Goat milk casein was hydrolyzed by using a combination of neutral and alkaline proteases to obtain goat milk casein hydrolysates (GMCH) with high antioxidant activity. After desalting by nonpolar macroporous absorption resin, GMCH was isolated and purified by gel filtration chromatography and reversed-phase HPLC, respectively, and further identified by nanoliter electrospray ionization-tandem mass spectrometry. Antioxidant activities of GMC, GMCH, and pure peptides were evaluated and compared using free radical scavenging activity, metal ion chelating ability, and anti-lipid peroxidation ability. Compared with GMC, the free radical-scavenging ability and ferrous ion-chelating ability of GMCH increased significantly. The inhibition effect of lipid peroxidation of GMCH was much stronger than that of tert-butylhydroquinone and phytogermine and a little lower than that of ascorbic acid. The antioxidant activity of GMCH could be attributed to the high antioxidant activity of oligopeptides, especially 5 novel oligopeptides: Val-Tyr-Pro-Phe, Phe-Gly-Gly-Met-Ala-His, Phe-Pro-Tyr-Cys-Ala-Pro, Tyr-Val-Pro-Glu-Pro-Phe, and Tyr-Pro-Pro-Tyr-Glu-Thr-Tyr, which were first observed in GMCH. The antioxidant activity of these 5 novel oligopeptides and GMCH increased 3.59 to 380 times compared with GMC, combining anti-lipid peroxidation ability of GMCH, which indicated that GMCH and its purified fractions in different stages could be used as functional food ingredients, food additives, and pharmaceutical agents in the future.
本研究描述了从山羊乳清蛋白（GMC）中制备、纯化和鉴定抗氧化肽的方法。使用中性和碱性蛋白酶的组合水解山羊乳清蛋白，得到具有高抗氧化活性的山羊乳清蛋白水解物（GMCH）。经非极性大孔吸附树脂脱盐后，分别通过凝胶过滤色谱和反相 HPLC 对 GMCH 进行分离和纯化，并用纳升电喷雾串联质谱进一步鉴定。采用自由基清除活性、金属离子螯合能力和抗脂质过氧化能力评价和比较 GMC、GMCH 和纯肽的抗氧化活性。与 GMC 相比，GMCH 的自由基清除能力和亚铁离子螯合能力显著提高。GMCH 的抑制脂质过氧化能力远强于叔丁基对苯二酚和植酸生育酚，略低于抗坏血酸。GMCH 的抗氧化活性可归因于其具有较高抗氧化活性的寡肽，特别是 5 种新的寡肽：Val-Tyr-Pro-Phe、Phe-Gly-Gly-Met-Ala-His、Phe-Pro-Tyr-Cys-Ala-Pro、Tyr-Val-Pro-Glu-Pro-Phe 和 Tyr-Pro-Pro-Tyr-Glu-Thr-Tyr，这是首次在 GMCH 中观察到的。与 GMC 相比，这 5 种新寡肽和 GMCH 的抗氧化活性分别提高了 3.59 至 380 倍，结合 GMCH 的抗脂质过氧化能力，表明 GMCH 及其不同阶段的纯化产物未来可作为功能性食品成分、食品添加剂和药物制剂使用。
