Changes in structural and functional properties of globulin–polyphenol complexes in mung beans: exploration under different interaction ratios and heat treatment conditions

Abstract

Summary In this study, mung bean was used as raw material to reveal the interaction mechanism between mung bean protein and polyphenols in the water solution system of heat treatment and to speculate the binding form of the two. Structural and functional changes of globulin–polyphenol complexes in mung bean under different interaction ratios and heat treatment conditions (70, 85 and 100 °C) were analysed using 2D and 3D fluorescence, Fourier transform infrared spectroscopy, particle size and ζ potential. The results showed that mung bean globulin–polyphenol binding was a static quenching mechanism, with mainly hydrophobic interactions. Heat treatment had little effect on binding sites and may induce partial covalent binding. Antioxidant activity of the interaction improved; however, heat treatment reduced the antioxidant capacity of the complexes. Before and after heat treatment, globulin–polyphenol complexes had poor solubility, but its emulsification and foaming ability are significantly improved. Polyphenol addition improved mung bean globulin secondary structure, and the thermal stability of the complex was greater than that of mung bean globulin. This study provides a theoretical reference for clarifying the binding mechanism of mung bean protein and polyphenols, which is significant for mung bean food processing and production.