Study On Mung Bean Peptides Prepared By Fermentation

China is a traditional large country that grows mung bean whose main processingform is mung bean starch. However， a lot of mung bean protein has not been fullyutilized in the process of mung bean starch. Some are used as forage， others aredirectly emitted， which not only pollutes environment but also wastes a great deal ofprotein. Using mung bean protein as raw materials， mung bean polypeptide withbiological activity is made by microorganism fermentation，which can not only improvethe added value of mung bean but solve the problem of environmental pollution. Thishas a positive and practical significance. This article includes the analysis of mung beanpolypeptide concentration in fermentation liquid of different fermentation conditions，optimizing fermentation conditions by using response surface method on the basis ofsingle factor experiment， analysis of protease activity of mixed strains in fermentationliquid and analysis of polypeptide antioxidant properties of mung bean as well as thesensory evaluation of fermentation products and so on. The main research results are asfollowings.First， ferment mung bean protein powder by Bacillus subtilis1.0892， Aspergillusnige3324and the mixed bacteria of Bacillus subtilis1.0892and Aspergillus nige3324respectively in proper conditions. Select different strains by mung bean polypeptidecontent in the fermentation liquid. The experiment shows that the best fermented resultis the mixed Bacillus subtilis1.0892and Aspergillus nige3324. The mung beanpolypeptide in fermentation liquid can reach1392.72μ g/mL， which is the highest inthe three fermentation liquid. On the basis of single factor experiment， were optimizedthe fermentation conditions by using response surface method， the optimalfermentation conditions were: mixing Bacillus subtilis1.0892and Aspergillus niger3324according to the ratio of1.6:1，at the temperature of30℃， initial Ph value of7.0，4.3%of substrate concentration and inoculum at10.3%. Fermenting under thiscondition for48hours， mung bean polypeptide fermentation liquid can reach1397.42μg/m.Second， measure the protease activity produced by the mixed bacteria of Bacillussubtilis1.0892and Aspergillus nige3324. The experimental results show that under thecondition of at the temperature of30℃， initial Ph value7， inoculation quantityof10%， mixing Bacillus subtilis1.0892and Aspergillus niger3324according to theratio of1.5:1， protease activity can reach up to376.8U/mL after fermenting for48 hours.Third， measure the antioxidation of the mung bean polypeptide according to thereducing capacity of mung bean polypeptide， the clearance rate of superoxide anions（O2-）and hydroxyl free radical (·OH). The experiments show that the mung beanpolypeptide has stronger reducing capacity. The clearance rate of superoxide anions is46.57%and that of hydroxyl free radical is47.26%.Fourth， make sensory evaluation of the three different strains. The experimentsshow that the mixed strain of Bacillus subtilis1.0892and Aspergillus nige3324has thebest sensory evaluation. The numeric value of bitterness and odor are small.