Effect of protein hydrolysates on advanced glycation end-products in frozen-thawed and reheated minced squid

The effects of the formation of advanced glycation end-products (AGEs), including N^ε-carboxymethyllysine (CML) and N^ε-carboxyethyllysine (CEL), in preheated minced squid treated with protein hydrolysates were investigated during frozen-thawed cycles and reheating. Lipid oxidation indexes, protein oxidation indexes and precursors of AGEs were also analyzed to explore the pathways of protein hydrolysates on AGEs and to reveal the mechanism of AGEs generation. During frozen-thawed cycles, the contents of AGEs, thiobarbituric acid reactive substances, glyoxal, and methylglyoxal in minced squid showed a continuous increasing trend, and the level of sulfhydryl groups decreased continuously. Reheating resulted in a significant increase in CML (53.4 − 160.4%) and CEL (2.7 − 76.9%), while glyoxal (4.6 − 11.9%) and methylglyoxal (2.0 − 11.8%) decreased. Protein hydrolysates inhibited both lipid oxidation and protein oxidation during frozen-thawed cycles and reheat compared to the blank group. The average level of AGEs in the experimental group after reheating was lower than that of the blank group by 37.0% (CML) and 32.9% (CEL). The results indicated that the addition of protein hydrolysates had a better inhibitory effect on the generation of AGEs during reheating.