Carotenoids from tomatoes inhibit heterocyclic amine formation

Tomatoes are a rich source of antioxidants and they are commonly used for meat cooking in Mediterranean countries. The effects of tomato antioxidants on the formation of carcinogenic/mutagenic heterocyclic amines were investigated. A liq. model system contg. as precursors creatinine, glucose and glycine in molar concns. comparable to those present in bovine meat (chem. model system) was employed. A freeze-dried bovine meat juice (meat juice model system) was also used for some expts. In both model systems, an inhibiting effect of tomato carotenoid fraction on the formation of imidazoquinolines (IQx, MeIQx and DiMeIQx) was obsd. Using carotenoid ext. at 1000 ppm, inhibitions of 36% and 11% of IQx and MeIQx formation resp. in the chem. system and of 13% of MeIQx and of 5% of 4,8-DiMeIQx in the meat juice system was obsd. The effect of the main tomato flavonoid, quercetin, was investigated using the meat juice system. Quercetin gave an inhibition of MeIQx formation between 9 and 57% with a max. effect of 67% at 10 ppm.