Effect of lipid oxidation on the color deterioration of ready-to-eat oysters: Discussion based on the model system

The contribution of lipid oxidation to color deterioration in ready-to-eat (RTE) oysters remains unclear. Therefore, this study established four polyunsaturated fatty acid (PUFA)-based model systems: P (PUFA), PG (PUFA + glucose), PA (PUFA + amino acids), and PAG (PUFA + amino acids + glucose). After accelerated storage (60 °C, 48 h), the browning index of the EPA- and DHA-added groups of the P system increased by 2.08- and 3.08-fold, respectively, indicating that lipid oxidation alone can cause browning. The browning extent followed P < PG < PA < PAG, indicating that glucose and amino acids independently and synergistically aggravated PUFA-induced discoloration. In PG and PA systems, glucose and amino acids enhanced coloration through radical-mediated reactions, respectively. The additional browning in the PA/PAG system was due to the formation of pyrrole and lipofuscin-like pigments. These results demonstrate lipid oxidation's key role in RTE seafood discoloration and provide a theoretical basis for quality control.