Effect of temperature, pH, metal ions, and oil type on Chinese quince proanthocyanidins' thermal stability, antioxidant activity, and inhibition of heterocyclic amine formation during simulated frying

Abstract

Heterocyclic amines (HCAs) are potent carcinogenic and mutagenic compounds generated during the frying of meat. The addition of Chinese quince proanthocyanidins (PAs) to fried food can reduce HCA formation. However, differences in food parameters (such as temperature, pH, presence of metal ions, and oil type) affect the efficacy of PA-mediated inhibition of HCA formation. In this study, two PAs (P1 and P2) of different molecular weights were prepared from Chinese quince. The effects of pH, metal ions, and oil type on the thermal stabilities, antioxidant capacities, and HCA-inhibitory abilities of P1 and P2 were studied during simulated frying. After simulated frying, the degree of polymerization (DP) and molecular weights of P1 decreased dramatically from 15224 Da to 2280 Da, while they decreased slightly in P2. Fe3+ decreased the thermal stability of P1 and P2 more than high pH; however, both factors reduced the HCA formation-inhibitory activity. Notably, the thermal stabilities of P1 and P2 in sunflower oil were lower than those in other oils; however, the inhibition of HCAs by P1 and P2 in sunflower oil (69.31% and 72.11%, respectively, for norharman) differed only slightly from that in the other oils. Multivariate analysis revealed positive correlations among thermal stabilities, antioxidant capacities, and HCA-inhibitory activities. Thus, Chinese quince PAs may be potentially used as food additives to mitigate the production of harmful HCAs in fried food.