Thermal degradation mechanism of myricetin in palmitic acid

Lipid oxidation governs myricetin degradation in heated palmitic acid. • o-Quinone formation triggers B-ring cleavage and oxidative dimerization. • Carbonyl addition and lipid-derived ester conjugates were detected. • Vitamin C suppresses radical-driven pathways and improves myricetin retention. Dietary polyphenols are susceptible to degradation during high-temperature cooking, yet their transformation behavior in lipid-rich frying systems remains poorly understood. The thermal stability and degradation of myricetin in a simplified palmitic acid model under frying-relevant conditions was investigated. Myricetin degraded rapidly at 180 °C but remained relatively stable at 120 °C. UPLC–QTOF–MS/MS, supported by density functional theory calculations, suggested that myricetin transformation is temperature-dependent but primarily governed by lipid oxidation–derived radical and carbonyl chemistry. Vitamin C markedly delayed myricetin degradation by suppressing radical initiation and limiting o -quinone–centered downstream reactions. These findings highlight lipid oxidation as a key determinant of polyphenol stability during frying and clarify the protective role of antioxidants in lipid-rich thermal processing systems. Download: Download high-res image (202KB) Download: Download full-size image