Protein derived from purple wheat bran was hydrolyzed sequentially using alcalase proteases for the production of antioxidant peptides. Purple wheat bran protein (PWBP) hydrolysates were fractionated using size-exclusion (G-25) and ion-exchange chromatography methods to identify the structure of antioxidant peptides. The free radical scavenging activity of peptides purified from PWBP hydrolysates was evaluated using superoxide anion radical-scavenging activity and determination assays of Trolox equivalent antioxidant capacity (TEAC). Results demonstrated that purple wheat bran peptide F4-4 exhibited the highest antioxidant activity among other hydrolysates. F4-4 was further identified as Cys-Gly-Phe-Pro-Gly-His-Cys, Gln-Ala-Cys, Arg-Asn-Phe, Ser-Ser-Cys, and Trp-Phe by high performance liquid chromatography (HPLC) spectrometer coupled with Orbitrap Elite™ mass spectrometer (LC–MS/MS). Antioxidant peptides 2 and 4 showed improved stability when the temperature was lower than 80 °C. These peptides also demonstrated good digestive stability in vitro system by simulating gastrointestinal digestion.

中文翻译：

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紫色麦麸中抗氧化肽的纯化，结构分析和稳定性

使用alcalase蛋白酶将紫色麦麸中的蛋白质顺序水解，以生产抗氧化剂肽。使用大小排阻（G-25）和离子交换色谱法对紫色的麦麸蛋白（PWBP）水解产物进行分级分离，以鉴定抗氧化剂肽的结构。使用超氧化物阴离子自由基清除活性和Trolox等效抗氧化剂容量（TEAC）的测定方法评估从PWBP水解产物纯化的肽的自由基清除活性。结果表明，紫色麦麸肽F4-4在其他水解产物中表现出最高的抗氧化活性。F4-4被进一步鉴定为Cys-Gly-Phe-Pro-Gly-His-Cys，Gln-Ala-Cys，Arg-Asn-Phe，Ser-Ser-Cys，高效液相色谱（HPLC）光谱仪和Orbitrap Elite™质谱仪（LC-MS / MS）结合使用Trp-Phe和Trp-Phe。当温度低于80°C时，抗氧化剂肽2和4表现出更高的稳定性。这些肽还通过模拟胃肠道消化而表现出良好的体外消化稳定性。