米曲霉发酵所制大豆肽的分离纯化与抗氧化性研究

利用辐照诱发米曲霉孢子突变,筛选得到酶活力强且特异性高的米曲霉诱变菌株。利用米曲霉诱变菌株对豆腐皮加工后的剩余豆浆(下浆水)进行发酵,制备大豆肽的发酵液,发酵液经超滤和凝胶过滤进行分离纯化,采用铁离子还原抗氧化剂能力测定法(FRAP法)和二苯基苦基苯肼法(DPPH法)研究不同相对分子质量大豆肽的抗氧化能力。结果表明,相对分子质量在1 000～10 000范围内的大豆肽具有很好的抗氧化活性,其中抗氧化性和稳定性最好的大豆肽组分的相对分子质量在1 200～1 400之间。

Purification and Antioxidant Activity Determination of Soybean Peptide Fermented from Soy Film By-products by Aspergillus oryzae

Aspergillus oryzae with strong enzyme activity and high specificity was screened from spore mutation through irradiation.Soybean peptides were made by soy milk remained from soy film by-products and fermented by Aspergillus oryzae.Purification of soybean peptides was then done through ultrafiltration and gel filtration.Antioxidant activity of purified soybean peptides with different molecular weight was determined using FRAP(ferric reducing antioxidant power) and DPPH(2,2-diphenyl-1-picrylhydrazyl) methods.The results showed that the sample with molecular weight between 1 000 and 10 000 had better antioxidant activity.The molecular weight of sample that had best antioxidant activity and stability was between 1 200 and 1 400.