Effects of heating and the addition of seasonings on the anti-mutagenic and anti-oxidative activities of polyphenols

Polyphenols are functional compounds in edible plants. In this study, we investigated the effects of heating and addition of seasoning, with and without heating, on the DPPH radical scavenging activity and the anti-mutagenicity effect against benzo(α)pyrene of polyphenols. Anti-oxidative activity and anti-mutagenicity of polyphenols were hardly influenced by heating without seasoning. Radical scavenging activity was clearly promoted by the addition of soy sauce, rice soybean paste, barley soybean paste and consommé, and a similar tendency was observed on the anti-mutagenicity of polyphenols by adding two kinds of soybean pastes. Marked increases in the activities of caffeic acid, and catechin occurred and epicatechin was several-fold more active than the seasoning itself. Heating around the boiling point enhanced the radical scavenging and anti-mutagenic activities of catechin, epicatechin, naringenin and naringin with seasoning addition. However, analysis showed differences of increments in these three polyphenols. More active reaction products might have been formed by interaction of constituents in the model system.