Synergistic inhibitory effects of EGCG and chitosan or sodium alginate on 5-hydroxymethylfurfural formation in biscuits

Heat-induced hazard 5-hydroxymethylfurfural (5-HMF) is detected in various baked foods. Although catechins and polysaccharides could inhibit 5-HMF, their inhibition efficiency was limited when used alone. Therefore, this study aimed to explore the synergistic inhibitory effect of catechins and polysaccharides on 5-HMF in biscuits. Epigallocatechin gallate (EGCG), chitosan, and sodium alginate were screened out due to their superior maximum inhibition rates (55.90%, 67.20%, and 66.62%, respectively), and their synergism were investigated by isobologram analysis. The interaction index (gamma) varies inversely with the synergism. When gamma < 1 or >1, it represented synergism or antagonism, respectively. The results showed that the synergism between EGCG and chitosan in the ratio of 1:1 (gamma = 0.221) was better than that of 1:2 and 1:3 (gamma = 0.671 and 0.523, respectively). Moreover, EGCG and sodium alginate only showed synergism in the ratio of 1:1 (gamma = 0.358), while antagonism was observed in the ratios of 1:2 and 1:3 (gamma = 1.12 and 1.25, respectively).The optimum inhibition rate (54.57%) on 5-HMF was reached when EGCG (0.1 g/kg) combined with sodium alginate (0.1 g/kg). Compared with those used alone, the co-addition of EGCG and chitosan could decrease the dosage of EGCG to 1/5 and that of chitosan to 1/7, indicating a significant improvement in inhibit efficiency. Finally, the concentration of inhibitors correlated negatively with 5-HMF content and browning index of biscuits, suggesting they might inhibit 5-HMF by hindering Maillard reaction or caramelization reaction. This study provided an efficient and cost-effective solution for 5-HMF control in baking products.