Anti-mutagenic and anti-oxidative activities found in Chinese traditional soybean fermented products furu

Furus, Chinese traditional soybean products, which are salted, fermented and seasoned bean curd preserved in dipping sauce, were studied for their anti-mutagenic and anti-oxidative activities. There are many varieties of furu by region, depending on their ingredients and bacterial strain used. Furus, not only have peculiar palatable taste and aroma, but also present strong anti-oxidative activity which ordinary Japanese soybean curd, tofu, never shows. Against benzo(α)pyrene, all samples, regardless of solid or dipping sauce, showed anti-mutagenic activity. In general, red furus had higher activity than white. All red furus inhibited more than 50% of the mutagenicity and this high suppressive ratio suggested that it was raised mainly by secreted substances discharged from the bacterial body rather than by functional compounds originating from soybeans. In the case of white furu, which showed wide differences in activity, the functional role of each spice and condiment added needs to be further studied, in addition to the soybean and white furu ferment-rice malt.