米曲霉固态发酵玉米胚芽粕对蛋白质理化性质及抗氧化性的影响

Physicochemical and antioxidant properties of corn germ protein extracted from fermented corn germ meal by Aspergillus oryzae

以玉米胚芽粕为原料,利用米曲霉对其进行固态发酵,随后从发酵产物中提取玉米胚芽蛋白,对比发酵前后提取的玉米胚芽蛋白的抗氧化性、表面疏水性、巯基含量及氨基酸含量的变化。以可溶性蛋白含量为指标,通过单因素试验和正交试验确定玉米胚芽粕的最佳发酵条件为接种量7. 2×108CFU/g、发酵时间6 h、料液比1∶2. 5,在此条件下玉米胚芽蛋白中可溶性蛋白含量为0. 827 g/g。与未发酵提取的玉米胚芽蛋白相比,发酵后提取的玉米胚芽蛋白的表面疏水性、游离巯基含量分别增加了10. 3和1. 5μmol/g,氨基酸总量和疏水性氨基酸总量分别提高了12. 49个百分点和6. 29个百分点,抗氧化性(DPPH自由基清除率、还原力)也有所提高。

The corn germ meal was used as raw material,and the solid state fermentation was carried out with Aspergillus oryzae.Then the corn germ protein was extracted from the fermented product,and the antioxidation,surface hydrophobicity,sulfhydryl content and amino acid content of the corn germ protein were compared before and after fermentation.With soluble protein content as an index,the optimal fermentation conditions were determined by single factor experiment and orthogonal experiment as follows:inoculation amount 7.2×10~8 CFU/g,fermentation time 6 h,ratio of material to liquid 1∶2.5.Under the optimal conditions,the soluble protein content in corn germ protein was 0.827 g/g.In comparison with the protein extracted from unfermented corn germ meal,the free sulfhydryl content and surface hydrophobicity of the protein extracted from fermented corn germ meal increased by 1.5μmol/g and 10.3 respectively,the total amino acid content and total hydrophobic amino acid content increased by 12.49 percentage points and 6.29 percentage points respectively,the antixoidant capacity(including DPPH free radical scavenging rate and reducing power)also increased.