| Soybean peptides have good physical and chemical properties and physiological functions, which can be well used in food and medicine areas. People pay more and more attention to the way which produces soybean peptides by the microbial fermentation. The method of fermentation in step is used in this subject to research the technology of producing soybean peptides by the solid-state fermented soybean meal with Aspergillus oryzae. Early in the fermentation, controlled the fermentation conditions to reach to the optimal conditions for the production of protease by the solid-state fermented soybean meal with Aspergillus oryzae. After getting the highly active protease, changed the fermentation conditions, making sure that the protease which was produced in the first step will be better working for the soybean meal, so people will get the real need of soybean peptides.This thesis focused on the following three aspects:(1)Researching on the optimal culture and fermentation conditions of the production of protease by the solid-state fermented soybean meal with Aspergillus oryzae. Make sure the optimal conditions of the production of protease by doing single complication test and orthogonal test. The optimal condition is: raw materials than the (soybean / wheat bran) 93%,water is 60%,material is 30g, Inoculum is 10%, KH2PO41.0%,the temperature of fermentation is 30℃, the time of fermentation is 66h.In this conditions, the production of protease by the solid-state fermented soybean meal with Aspergillus oryzae has the highest activity which is 975.74U/g.(2)Researching on the methods of measuring the activity of protease. By measuring the activity of the protease by the method of Folin-phenol, at the same time, improving the traditional method of Formaldehyde, we got the two right methods for the subject which are the method of Folin-phenol and the method of improved Formaldehyde.(3)Researching on the optimal conditions of hydrolysis of producing soybean peptides by the solid-state fermented soybean meal with Aspergillus oryzae. The optimal conditions of hydrolysis is: the temperature of hydrolysis is 50℃, the time of hydrolysis is 4h, peptide conversion rate is 46.10%.Finally, compared with the traditional fermentation that the time of fermentation has been reduced 26h, the peptide conversion rate has been increased 5.91%. Therefore, the research on the technology of producing soybean peptides by the solid-state fermented soybean meal with the method of fermentation in step in this subject has proved to reduce the time of fermentation and increase the peptide conversion rate, it has an important significance in the production and application. |
