Enhancing the in vitro Antioxidant Capacities via the interaction of amino acids
In this article, antioxidant capacities of 20 amino acids were quantitatively determined via methodology of mixing one amino acid with the others and using four antioxidant assays to understand the synergistic effects of the individual amino acid contributing to the total antioxidant capacity. Some of the individual amino acids and their mixtures showed their characteristics of antioxidant capacities, and antioxidant peptides showed different results in different experiments. From the ABTS assay study, it was found that nine of 20 amino acids had antioxidant capacities, and most of their mixtures had synergetic effects, Moreover, an oxygen radical absorbance capacity assay study was conducted, and the results aligned well with the ABTS study. However, the DPPH and FRAP assay studies, indicated that cysteine was the only amino acid having antioxidant effect in 20 amino acids. The result showed that the combinations of high antioxidant amino acids and weak antioxidant amino acids or non-antioxidant amino acids led to an obvious increase in antioxidant capacity compared with the theoretical antioxidant capacity.