双酶法制得米糠蛋白肽抗氧化组分的分离纯化

Separation and Purification of Rice Bran Antioxidant Peptide with Bienzyme

利用双酶法水解制得了米糠蛋白。以制得的具有生物活性的米糠蛋白多肽混合液为原料,分离纯化得到了米糠蛋白抗氧化肽,为米糠及其蛋白的深加工奠定理论基础。利用木瓜蛋白酶和风味蛋白酶双酶水解制备米糠蛋白肽。以DPPH·,·OH清除率为主要指标,采用不同截留分子量（1.0×10~4和3×10~3 Da）的超滤膜对米糠蛋白肽进行初步分离,获得3种不同分子质量组分,再利用SP-Sephadex C-25离子交换色谱和Sephadex G-25凝胶色谱,逐步分离纯化出单一的抗氧化肽段。采用RP-HPLC证明了分离肽段的均一性,同时分析检测出该肽段的氨基酸组成,明确肽段抗氧化活性与其氨基酸组成的关系：它是由13种氨基酸组成,其中Glu和Asp摩尔分数分别为21.46%和15.57%,还有7种人体必需氨基酸,占米糠蛋白抗氧化肽氨基酸总含量的39.2%。

The rice bran protein hydrolysates induced by bienzyme were separated and purified to get antioxidant peptides.The purpose was to provide the theoretical foundation for the processing deeply in the rice bran and its protein.Rice bran peptides hydrolyzed by compound enzyme of papain and flavorase were prepared.With DPPH radical scavenging and hydroxyl radical-scavenging as main indicators,rice bran peptides were preliminarily separated and purified by ultrafiltration with different molecular weight membrane（1.0×10~4 and 3×10~3 Da）,and then further purified by SP-Sephadex C-25 ion exchange chromatography and Sephadex G-25 gel chromatography.So a single antioxidant peptide was gotten from separating step by step and identified by RP-HPLC and its amino acid composition was detection.The relationship between antioxidant activity and amino acid composition of peptide was clear.The peptide was constituted of 13 amino acids,which of Glu and Asp made up of 21.46% and 15.57%,respectively.There were also 7 essential amino acids,and accounted for 39.2% of the total of amino acids of rice bran protein antioxidant peptide.