The Study On Producing Technology Of Nutritional Soy Sance With Rich Isoflavone Aglycones

This thesis studied on the producing technology of soy sauce, and attempted to increase the content of isoflavone aglycones in soy sauce, and also offered the new producing methods and parameters to explore the nutritional soy sauce.Study on screening the high yieldβ-glucosidase-producing strain. Traditional fermented soy sauce as material to gain the Aspergillus oryzae by activating,isolating and purifying, and which was screened the high yieldβ-glucosidase-producing strain with the Aspergillus oryzae keeped in the lab. The method of transparent collar was used in the first selection, and re-selected by comparing sporus amounts among different strains, and ter-selected by comparingβ-glucosidase activity of soy sauce koji fermented by different strains. At last, M2 strain was comfirmed of the high yieldβ-glucosidase-producing strain, and was used in the study on optimum technological conditions of making soy sauce koji and fermenting soy sauce.Study on the optimum technological conditions of making soy sauce koji.β-glucosidase activity as index to obtain the optimum conditions:soybean was soaked for 4h, cooked for 15min at 121℃, 1mL Aspergillus oryzae liquid (5×108cfu/mL) was inoculated in 100g soybean, fermented koji in 32℃,and fermention time was 84h. The influence level of producingβ-glucosidase from big to small was soybean soaked, time of making koji and temperature of making koji, and each condition was notable. The manifested test demonstrated that theβ-glucosidase activity of wet basis was 385.78 U/g, and theβ-glucosidase activity of dry basis was 537.86 U/g under the optimum conditions.Study on the optimum technological conditions of fermenting soy sauce. The contents of Daidzein, Genistein, Daidzin and Genistin were used as indexes and HPLC as determining method to reseach the optimum conditions of fermenting soy sauce based on time, temperature, imbitition and pH. The optimum technological conditions for fermenting soy sauce were as followed:fermentation time 10d, temperacture 44℃, imbitition 200mL, pH6.2. The manifested test demonstrated that Genistein was 103.03ug/g and Daidzein was 105.12ug/g, and corresponding Genistin was 15.76ug/g and Daidzin was 23.19ug/g under the optimum conditions, which were preponderant compared with soybean and other soybean product.Determination of the physical, chemical and microbial indexes of soy sauce was carried in this research. The isoflavone content of the soy sauce was 0.381mg/g. According to the method of GB2718-2003 (Method for analysis of hygienic standard of soybean sauce), the detection of the physical, chemical and microbial indexes of soy sauce were confirmed as follows: aminonitrogen content was 0.86g/100g, total acidity was 1.85g/100g, total arsenicum content was 0.02mg/Kg, lead content was 0.01mg/Kg, and aflatoxin BⅠcontent≤5ug/Kg. And the microbial indexes were as follows:bacillus coli were negative, pathogenic bacteria weren't detected. All indexes were consistent with the requirement of GB2718-2003.