Antioxidant activity of Maillard reaction products from a Yak casein-glucose model system

Maillard reaction products (MRPs) were prepared by reacting both Yak and Holstein casein with different ratios of glucose to casein from 0:1 to 2.5:1. The results showed that the content of intermediate products and browning intensity of the Yak casein-glucose system increased with increasing concentrations of glucose, but were lower than for the Holstein system at the same ratio. With glycosylation, the reducing power and the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of both Yak and Holstein caseins were enhanced. With increased glucose content, the reducing power of Yak MRPs increased at the same concentration. The metal chelating activity of Holstein MRPs decreased or was eliminated in the ratio range of 0.5:1 to 2.0:1 g glucose g −1 casein, while that of Yak MRPs were reduced in general. Improvement of the inhibitory activity for Yak casein was lower than that of Holstein casein after glycosylation by glucose.