Dietary vitamin E effects on the formation of heterocyclic amines in grilled lean beef

The effects of tissue antioxidant levels on formation of heterocyclic amines (HAs) and their mutagenicity in grilled lean beef were studied. Meat from 54 feedlot steers fed different levels of vitamin E (340, 690, 1040 and 1740 IU/animal/day) for 120-days was used to provide beef with different levels of antioxidants (α-tocopherol). Prevalent HAs were then analyzed by HPLC using UV/Fluorescence detection. Five major HAs were found: 2-amino-3,8-dimethyl-imidazo(4,5-F)Quinoxaline (MeIQx), 2-amino-3,4,7,8-tetramethyl-imidazo(4,5-F)Quinoxaline (TriMeIQx), ß-Carboline-9H-Pyrido[3,4-b]indole (Norharmane), 1-Methyl-9H-pyrido[3,4-b]indole (Harmane) and 2-amino-1-methyl-6-phenylimidaza(4,5-B)pyridine (PhIP). Total content of HAs in grilled lean beef ranged from 9.57 ng/g to 11.59 ng/g. There was, however, a trend (P = 0.097) found for reduced mutagenicity with increasing tissue levels of α-tocopherol. The increasing dietary vitamin E significantly increased the α-tocopherol level in lean beef (P < 0.001), but it had no significant (P > 0.05) inhibitory effects on the content of individual and total HAs.