本研究通过体外模拟胃肠道消化海洋鱼蛋白低聚肽，运用高效凝胶过滤色谱、紫外全波长扫描、圆二色光谱表征其消化前后结构变化，测定其消化前后DPPH自由基清除率、ABTS自由基清除能力、铁离子还原能力（FRAP）及氧自由基吸收能力（ORAC）的变化，以探究模拟胃肠道消化对海洋鱼蛋白低聚肽结构及抗氧化活性的影响。分子量分布数据揭示了海洋鱼蛋白低聚肽中分子量为150~1000 u的组分为其主要组成部分，所占比例最高可达88.39%；紫外全波长扫描、圆二色光谱扫描表明海洋鱼蛋白低聚肽对胃蛋白酶有很强的抗消化稳定性以及对胰蛋白酶有较好的抗消化稳定性。在浓度1~15 mg/mL范围内，海洋鱼蛋白低聚肽的DPPH自由基清除率与其浓度成正相关，最高为67.86%；ABTS自由基清除能力、FRAP值及ORAC值三个抗氧化指标均显示海洋鱼蛋白低聚肽在消化后其抗氧化活性均有一定程度的提高，其中ORAC值在先胃蛋白酶后胰蛋白酶消化后提高最显著（p<0.01）。总之海洋鱼蛋白低聚肽的结构和抗氧化活性均具有抗消化稳定性。

In this study, marine fish protein oligopeptides (MFPO) were digested through simulated gastrointestinal tract in vitro. The gel filtration chromatography, UV full wavelength scanning and circular dichroism spectrum were used to characterize the structure changes before and after digestion. DPPH free radical scavenging rate, ABTS free radical scavenging capacity, ferric ion reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) were measured before and after digestion to explore the effect of simulated gastrointestinal digestion on antioxidant activity of MFPO. The components with molecular weight of 150~1000 u were the main components of MFPO, accounting for up to 88.39% revealed by the molecular weight distribution data. The MFPO was proved to have strong anti-digestion stability to pepsin and good anti-digestion stability to trypsin by UV full wavelength scanning and circular dichroism spectrum scanning. In the concentration range of 1~15 mg/mL, the DPPH free radical scavenging rate of MFPO was found positively correlated with their concentration, and the highest was 67.86%. The other three antioxidant indexes including ABTS free radical scavenging capacity, FRAP and ORAC were also determined that the antioxidant activities of MFPO increased to a certain extent after digestion, among which the ORAC value increased most significantly after pepsin followed by trypsin digestion (p<0.01). The results showed that the structure and antioxidant activity of MFPO had anti-digestion stability.

国家重点研发计划项目（2016YFD0400604）；国家自然科学基金项目（31671963）；北京市科技创新基地培育与发展工程专项（Z191100002819001）