| In this paper, corn gluten meal as research object were studied through the methodology of enzymatic hydrolyze to obtain short peptide mixture, in additional to refining, discussing the corn peptide's antioxidant activity. The solubility of corn gluten meal was increased and the hydrolysates have a lot of physiological activity, which profits the important theoretical and practical value to improving corn gluten meal in food industry.Studying the decolouring of hydrolysis solution, discussing the decolouring effects using powder active carbon,granular active carbon,clay and diatomite,determined powder active carbon is the best decolourant, and used it made single factor and orthogonal test, the results showed that high degree of discolouration could be obtained under the following condition: powder active carbon 2%,pH 5.0,temperature 60℃,time 60 min, under this condition, the decoloration rate was 69.7% and the nitrogen recovery was 76.7%.Use the hollow fiber ultrafiltration membrane of 3 KDa to isolated the corn decolouring of hydrolysis solution, the optimal ultrafiltration condition was at 25℃with pressure 0.1 MPa and time 15 min.Salt was removed by ion exchange resin , the results showed that different concentrations of corn peptide solution have greater impact on the desalination effect, when the corn peptide concentration was 50 mg/mL, not only desalination rate was more than 80%, and nitrogen recovery rate was much higher than the 20 mg/mL; velocity affects both the nitrogen recovery rate and desalination rate, but has greater effect of the nitrogen recovery rate. In this paper, when the core peptide in 10-fold column volume / h velocity through the ion exchange resins, the nitrogen recovery rate was 66.14 %, and the desalination rate reached over 80%.Comparison of different hydrolysis time, different concentrations of corn peptide's antioxidation ability before and after decolouring, through three aspects comprehensive evaluation from the clear·OH free radical and the DPPH free radical ability and the restore ability ,the results show that: With the hydrolysis time increased, the antioxidant capacity of corn peptide are constantly changing, when the hydrolysis time was 3 h, its on the DPPH radical scavenging rate was over 80% ; after decolouring the antioxidant capacity of corn peptide stronger than before decolouring; with Vc as contrast, in the concentration range of 0.5 ~ 4.5 mg/ml, the corn peptide antioxidant capacity smaller than Vc, but with the corn peptide concentration increased, its antioxidant capacity gradually increased, when the corn peptide concentration of 4.0 mg/ml , its DPPH radical scavenging rate was 87.7%.By studying the physicochemical properties of corn peptide, it was found that corn peptide had good solubility, which was over 95% in pH 2 ~ 10; viscosity is low, when its solution concentration was 40%, its viscosity only 4.2 mPa﹒s; at a certain concentration conditions, it has good foaming and foam stability; in different humidity conditions, the hygroscopicity is different, under the same conditions, the corn peptide's hygroscopicity was more than soybean peptide. The distributing of molecular weight and contents of amino acid for corn peptide were determined by HPLC. The results indicate that the molecular weight of most of corn peptide are below 3000Da before ultrafiltration, the molecular weight below 1000Da were predominated 94.31%; after the ultrafiltration With the 3 KDa ultrafiltration membrane. The content of mixture fractions of ultrafiltration (molecular weight below 1000Da) was 98.46%. Comparing with corn protein, most of the amino acid composition and content have no significant difference and the corn peptide has greater content of glutamic acid, leucine, alanine and phenylalanine .
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