Trapping phenylacetaldehyde by litchi shell polyphenols and their characteristic catechins in chemical model and roast pork patty: Identification of catechins-adducts and toxicity assessment

Inhibitory effects of litchi shell polyphenols (LC) and their characteristic catechins on 2-amino-1-methyl-6-phenylimidazole [4,5-b] pyridine (PhIP) formation were investigated in chemical model and roast pork patty. Eight catechins-adducts were identified by UPLC-Q-TOF-MS and their toxicity were evaluated by Discovery Studio. Results showed inhibition rates of LC on bound-PhIP could reach 10.95 % and 100 % respectively in both chemical model and roast pork patty, and inhibition rates on free-PhIP could reach 76.47 % in roast pork patty. However, LC had no inhibiting effect on free-PhIP, and even promoted it in chemical model. UPLC-Q-TOF-MS indicated that Epicatechin (EC), Epigallocatechin (EGC) and Epigallocatechingallate (EGCG) eliminate PhIP by capturing phenylacetaldehyde to form adducts. LD₅₀ of the formed adducts were lower than the chronic rat oral loael value, indicating that EC, EGC and EGCG would not form more toxic adduct during PhIP reduction. This study provides a new perspective for the application of LC in inhibiting PhIP and a reference for improving the theoretical system of dietary polyphenols in inhibiting heterocyclic aromatic amines.