Enhancement of antioxidant, carbonyl scavenging and anti-glycation activities of polysaccharide-based hydrocolloids by covalent grafting with gallic acid.

Carbonyl stress contributes to pathological disorders leading to the progression of a variety of chronic diseases. Exploration of food ingredients with carbonyl scavenging capacities became one of the most potential strategies for the prevention of these diseases. Polysaccharide-based hydrocolloids have wide application approaches in the food industry. However, the carbonyl scavenging capacity of some natural polysaccharide-based hydrocolloids is unsatisfactory due to structural limitations. In this research, gallic acid (GA) was grafted onto different hydrocolloids (xanthan gum, carrageenan, carboxymethylcellulose, carboxymethyl chitosan (CMCS), and sodium alginate) by a free radical-mediated reaction to improve their antioxidant, carbonyl scavenging, and anti-glycation activities. The antioxidant activity of hydrocolloids was significantly improved after GA grafting. Among them, CMCS-GA (graft ratio 15.45 mg GA/g) exhibited the same ABTS scavenging ability as the equivalent amount of free GA and Vc. The carbonyl scavenging capacity, and the inhibitory effects on the fluorescent advanced glycation end products (AGEs) and protein oxidation products of some hydrocolloids also increased significantly GA grafting. The scavenging capacity of CMCS-GA on MGO, GO, ACR, and MDA in the model reaction increased by 220 %, 100 %, 6 %, and 58 %, respectively. Overall, CMCS-GA showed the best performance in radical scavenging, carbonyl scavenging, and AGEs inhibition compared to all the other hydrocolloids investigated. The findings showed that grafting GA onto hydrocolloids is a viable strategy to enhance the carbonyl scavenging capacity and anti-glycation activity of hydrocolloids.