In vitro antioxidant and cytoprotective properties of Maillard reaction products from phloridzin-amino acid model systems.

BACKGROUND The aim of this study was to investigate in vitro antioxidant activities and cytoprotective effect of Maillard reaction products (MRPs) from phloridzin (Pz)-amino acid model systems. Their structures were also characterized by Fourier transform-infrared spectroscopy (FT-IR). RESULTS MRPs were prepared from the Pz-methionine (Met), Pz-lysine (Lys), Pz-isoleucine (Ile), Pz-histidine (His) or Pz-glutamic acid (Glu) model system. The Pz-Lys MRPs, rich in antioxidant potency, were subjected to ultrafiltration to yield four MRPs fractions with different molecular weights (Mw). The fraction with Mw 30–50 kDa had significantly (P < 0.05) higher antioxidant activity than other fractions. Moreover, it significantly (P < 0.05) attenuated the 2,2′-azobis (2-methylpropionamidine) dihydrochlorid (AAPH)-elicited decrease in cell viability in HepG2 cells in a concentration-dependent manner. FT-IR analysis indicated that the fraction with Mw 30–50 kDa had the strong stretching vibration for the O-H, N-H, C-H, C = O and C = C groups, suggesting the formation of intermediate MRPs during Maillard reaction. CONCLUSION The results obtained in this study may provide some basis for the purported health-promoting effects of MRPs and their potential application as antioxidant agents in food industry. Also, it is important for our understanding of the variation of bioactive substances in food during thermal processing.