Electron paramagnetic resonance (EPR)-verified autoxidation and hydrolysis induce lipid degradation in pan-fried hand-grasp pancakes

Auto-oxidation occurs during pan-frying of hand-grasp pancakes. • Hydrolysis was observed during the pan-frying process. • Lipid degradation was detected in hand-grasp pancakes during pan-frying. • The content of unsaturated fatty acids decreased following pan-frying. • The levels of unsaturated triacylglycerols declined post pan-frying. This study investigated the effects of pan-frying on fat quality in hand-grasp pancakes. The results demonstrated that fats exhibited significant quality deterioration: acid value increased by 50%–85%, peroxide value rose by 175%–490%, and p-anisidine value elevated by 65%–430%. The increments of conjugated diene value and conjugated triene value ranged from 20% to 50% and 35% to 73%, respectively. Meanwhile, the DPPH radical scavenging capacity decreased by 3%–30%, indicating a remarkable decline in antioxidant activity. Statistical analysis revealed consistent compositional changes in post-frying fats: the average free fatty acid (FFA) content in fats of the six brands of hand-grasp pancakes increased by 113.04%, whereas the average contents of unsaturated fatty acid (UFA) and unsaturated triacylglycerol (UUU) decreased by 1.81% and 4.82%, respectively. Electron paramagnetic resonance (EPR) measurements confirmed the presence of alkyl radicals (R•) in pancake fats verifying that autooxidation served as the primary oxidation pathway of fats in hand-grasp pancakes. This study provides theoretical foundations for the development of dedicated fats and quality improvement of hand-grasp pancake products.