Abstract:In this study，the soy protein isolate powder was added in traditional sweet flour paste.To investigate a new type of sweet flour paste，we used the low-salt solid soy sauce fermentation process，through detection of physical and chemical indicators，organic acids and volatile flavor compounds in conjunction with the sensory evaluation，to determine the koji making time and ratio of raw materials.The results showed that the glucoamylase activity and protease activity of different ratio of raw materials at 40 h were highest during making koji.When the ratio of raw materials flour and soy protein isolate powder was 9 ∶1（mass ratio）and the koji making time was 40 h，the physical and chemical indicators were reasonable.7 kinds of organic acids were detected and the content of tartaric acid，malic acid，acetic acid，lactic acid and citric acid was higher than that of other groups.The detection of volatile flavor compounds was in most species，36 species.The sensory evaluation scores on other indicators scored were no less than the case of other groups，particularly full-bodied score.