Abstract:Soybeans, flour, and bran were used as raw materials to prepare high-salt dilute soy sauce, and the dose dependent effects of bran addition on the soy sauce physicochemical indices and antioxidant capacity were explored. Headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) were performed to detect and analyze the aromatic components of soy sauce samples. Koji protease activity was highest, and amino acid nitrogen (0.87 g/mL) and total nitrogen (1.81 g/mL) were most abundant when the ratio of soybean, flour, and bran was 7:2:1 (S2). Compared with the control soy sauce, the antioxidant capacity of soy sauce fortified with bran was significantly enhanced; the respective reducing powers of S2 (7:2:1) and S3 (7:1:2) were 30.38% and 20.85% higher than that of S1 (7:3:0) at the end of fermentation. The respective DPPH free radical scavenging rates of S2 and S3 were 31.818% and 28.59% higher than that of S1 (P<0.05). Sixty volatile flavor compounds were detected in soy sauce with bran added. Bran addition significantly increased the types and contents of aldehydes, acids, and heterocyclic compounds in soy sauce, enriching the aroma components of soy sauce richer, and improving its quality and flavor. These results are informative, promote the high-value utilization of bran in soy sauce production, and significantly contribute to the optimization of soy sauce brewing technology.
