Effect of tannic and gallic acid on glycation of egg white protein and formation N-(Carboxyl methyl) lysine

Abstract

The present study assessed the effect of incorporation of different concentrations of tannic acid (TA) and gallic acid (GA) (0.12, 0.5 and 1%w/v) in heat-treated egg white (EW) protein and glucose (Gl) (120 °C within 20 min) at 3:3% w/w on Carboxyl methyllysine (CML) formation using RP-HPLC and fluorescence detector. TA and GA at concentrations of 0.12 %w/v led to 6-folds decrease in CML content in comparison with EW-Gl where the CML level reached nearly 50 and 42 μg/mL, respectively, after 20 min heating. The evaluation of Maillard reaction products (MRP) formation during the heating process using antioxidant activity and fluorescence intensity tests indicated that there were significant inverse relationships between fluorescence intensity and antioxidant activity in all samples especially at the first minute of the heating process. The result of FTIR and SDS-PAGE confirmed that in the presence of TA and GA, the rate of glycation of protein significantly diminished in comparison with EW-Gl. The level of intercellular reactive oxygen species in Human umbilical vein endothelial cells (HUVEC) using TA and GA-containing samples were lower than when using heat treated EW-Gl samples. Moreover heat-treated TA and GA containing samples showed high antibacterial activities. The results indicated that TA and GA have a good potential in the enhancement of safety heat-treated food products through its antioxidant and antimicrobial activities, and also preventing CML production.