Effect of Antioxidants on 3-Chloropropanol Esters, Glycidyl Esters and Physicochemical Properties in Rapeseed Oil with Different Ingredients during Intermittent Frying

Using rapeseed oil as the frying medium, this study conducted the intermittent frying of chicken wings, french fries, and youtiao (fried dough sticks) by adding synthetic antioxidant tert-butylhydroquinone (TBHQ) and natural antioxidant rosemary extract. The research investigated how these antioxidants influence 3-chloropropanol esters (3-MCPDE), glycidyl esters (GEs), and physicochemical properties in rapeseed oil under different frying durations and food matrices, while analyzing inter-indicator correlations. The objectives were to reveal the regulatory patterns of antioxidants on 3-MCPDE, GEs, and oil quality during intermittent frying of different foods, and to evaluate their antioxidant capacities. Results showed that after 5 d of intermittent frying, all three fried foods exhibited distinct compositional changes in their respective oils, with a highly significant positive correlation (P<0.01) between 3-MCPDE and GEs levels. Oil quality parameters consistently deteriorated across all food types. The addition of 0.7 mg/kg rosemary extract demonstrated maximum inhibition rates of 8.30% on 3-MCPDE in french fries oil and 6.77% on GEs in chicken wing oil, while moderately suppressing the increase of saturated fatty acids (SFA) and trans-fatty acids (TFA), as well as the degradation of polyunsaturated fatty acids (PUFA) in all three oils. TBHQ at 0.2 mg/kg showed a 4.45% inhibition rate on GEs formation in french fries oil. Both antioxidants effectively inhibited deterioration of acid value, iodine value, and peroxide value to varying degrees. Under the experimental conditions, rosemary extract exhibited superior capability in preserving rapeseed oil quality compared to TBHQ. The study emphasizes that risk factors generated during high-temperature frying of foods in rapeseed oil warrant significant attention.