铁离子螯合亲和层析分离抗氧化活性核桃肽

采用铁离子螯合亲和层析方法分离出具有不同抗氧化活性的核桃肽,并探讨核桃肽的抗氧化活性与铁结合能力的关系。结果表明,核桃肽在酸性条件(pH 5.5)下与铁的结合能力最强,随着pH逐渐升高,结合能力下降。磷酸氢二钠对吸附到铁亲和层析柱上核桃肽的洗脱效果最好,通过阶段洗脱,得到铁结合能力逐渐增强的核桃肽组分(F1、F2和F3)。对其总还原能力和2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)自由基清除能力进行测定,发现其抗氧化能力为F3>F2>F1(P<0.05)。结果表明,核桃肽的铁结合能力越强,其抗氧化活性越高。

Separation of Antioxidant Walnut Peptides with Immobilized Metal Affinity Chromatography

Walnut is an important forestry product. The peptides hydrolyzed from walnut protein have the antioxidant activities. In this study, immobilized metal affinity chromatography (IMAC) was used to separate the walnut peptides with different antioxidant activities. The results showed that the binding abilities of walnut peptides on iron column were highest at pH 5.5. The binding amount of peptides decreased with the increasing of pH. The amount of eluted walnut peptides from column with Na2HPO4 was higher than that of other solutions. With stepwise elution, there fractions (F1, F2, and F3) were obtained. Furthermore, the antioxidant activities of the tree fraction were evaluated with reducing power and 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) system. The peptides from F1 to F3 presented improving antioxidant activity. Our results showed that the stronger iron binding ability of the walnut peptides, the higher antioxidant activities.