Effect of tea polyphenols on the formation of advanced glycation end products (AGEs), functional and structural properties of modified protein in Maillard reaction

To improve the solubility and processing properties of gluten protein, Maillard reaction at three temperatures (70 degrees C, 100 degrees C and 130 degrees C) was used to modified gluten, and the effect of tea polyphenols (TPs) on the functional and structural properties of Maillard reaction products (MRPs) were investigated. The results showed that higher temperature and TPs increased significantly (p < 0.05) the antioxidant activity of MRPs and the order was ABTS > TRC > DPPH, which maxima were 72.5%, 61.5% and 44.3%, respectively, when the TPs addition was 0.3 g/100 mL at 130 degrees C. After undergoing thermal treatment, significant increase of foamability and emulsifying stability was observed, while the foam stability and emulsifying activity decreased with the addition of TPs. TPs altered the maximum UV absorption value and caused a red-shift for MRPs. Additionally, the reduced fluorescence intensity indicated that TPs decreased the amount of Maillard reaction intermediates as well as AGEs. Furthermore, 0.3 g TP/100 mL significantly increased (p < 0.05) hydrophobicity with maximum of 48.6%, while beta-sheet content decreased from 45.7% to 40.4% compared to the control. The Maillard reaction improved the processing properties of gluten protein, and TPs effectively inhibited the production of AGEs and 5-hydroxymethylfurfural.