Comparison of five thermal treatments on the formation of Nε-carboxymethyl-lysine in duck breast

Abstract

This study aimed to investigate the effect of five thermal processing methods: boiled (95 ± 2 °C for 15 min, B95/15); deep-fried (180 ± 2 °C for 10 min, DF180/10); pressure braised (121 ± 2 °C, 0.15 MPa for 15 min, AE121/15); pan-fried (160 ± 2 °C for 10 min, PF160/10); and roasted (200 ± 2 °C for 15 min, R200/15) on the level of Nε-carboxymethyl-lysine (CML) in duck breast. The processing methods exhibited distinct mechanisms on CML formation in duck breasts, with the heat treatment directly affecting the moisture status. The B95/15 was affected by lipid oxidation. Furthermore, peroxidation production denatured the protein structure during deep-frying, promoting CML formation. Pressure braising had a complex effect on protein denaturation, while high pressure (0.15 MPa) led to the loosening of myofibrillar protein (MP) structure and deamidations that could also be responsible for protein hydrolysis and unfolding. The CML contents in pan-fried samples were related to protein folding and aggregation due to disulfide bond formation. The high roasting temperature on the antioxidant system damaged the meat structure, resulting in protein oxidation. Overall, this study provides some insights into the reduction and control of CML in processed duck meat.