Polymerization-Dependent Thermal Stability of Chinese Quince Proanthocyanidins and Their Inhibition of Heterocyclic Amines in a Simulated Frying System

Heterocyclic amines (HCAs), a class of potent mutagenic and carcinogenic compounds generated during the high-temperature processing of protein-rich foods, pose significant health risks to humans. Proanthocyanidins (PAs) are used to inhibit HCAs due to their low toxicity and strong inhibitory activity. However, PA activity may vary at different temperatures. In this study, PAs with different degrees of polymerization were heated at 180 °C to evaluate their thermal stability and inhibition of HCAs. With increasing temperature, the antioxidant activities of highly polymerized PAs (PPA) and oligomeric PAs (OPA) decreased. OPA demonstrated higher residual rates and antioxidant activities compared to PPA. Following simulated frying, the thermal stability of OPA and PPA decreased, while total oligomeric PA content increased. OPA exhibited stronger inhibition of HCAs than PPA, while PPA-180 (PPA after heating at 180 °C) and OPA-180 (OPA after heating at 180 °C) had a stronger inhibitory effect compared to PPA and OPA, respectively. In the HCA model system, OPA-180 stood out by exhibiting the highest inhibition rates. The study provides a foundation for the inhibition of HCAs by PAs.