体外模拟消化对海洋鱼骨胶原低聚肽结构和抗氧化活性的影响

The effect of simulated digestion in vitro on structure and antioxidant activity of marine fish bone collagen oligopeptides

该研究以海洋鱼骨胶原低聚肽为研究对象,通过体外模拟肠胃液消化,分析了消化前后海洋鱼骨胶原低聚肽的分子质量分布,其中模拟先胃液后肠液消化后分子质量<1 000 u的组分和重均分子量降低最多(约23.95%),其他消化模式处理组分子质量变化较稳定;紫外全波长扫描显示,消化前后溶液中酪氨酸变化量小于5%;圆二色光谱分析结果表明,模拟先胃液后肠液消化后反平行式β-折叠减少最多,为24.12%,其余二级结构,变化不超过8.33%,同时其余处理组二级结构组成相对稳定,表明海洋鱼骨胶原低聚肽能够在一定程度上耐受胃肠道中胃蛋白酶和胰蛋白酶作用。通过测定DPPH自由基清除率、ABTS阳离子自由基清除率、铁离子还原能力及氧自由基吸收能力4个指标,推测出海洋鱼骨胶原低聚肽不仅在分子质量和结构方面具有抗消化稳定性,其抗氧化能力也具有抗消化稳定性。这为海洋鱼骨胶原低聚肽在天然抗氧化功能食品中的应用提供了理论基础。

Marine fish bone collagen oligopeptides(MFBCO) were used as the raw material in this study to explore their molecular mass distribution before and after simulated gastrointestinal digestion in vitro. The components with molecular weight less than 1000 u and the average molecular weight decreased by up to 23.95% after simulating digestion of gastric fluid before intestinal fluid, and the molecular weight changes of other digestion mode treatment groups were more stable. Ultraviolet full-wavelength scanning results showed that the change of tyrosine in the solution before and after digestion was less than 5%. Furthermore, circular dichroism spectroscopy analysis results showed that the content of antiparallel beta-folding decreased by 24.12% after simulating digestion of gastric fluid before intestinal fluid, and the changes of other secondary structures did not exceed 8.33%. Moreover, the secondary structure composition of other treatment groups was relatively stable which indicating that MFBCO could tolerate pepsin and trypsin in the gastrointestinal tract to some extent. DPPH free radical scavenging activity, ABTS free radical scavenging activity, ferric reduction ability plasma assay(FRAP) and oxygen radical absorbance capacity(ORAC) were further determined. It was inferred that MFBCO not only had anti-digestion stability in molecular weight and structure, but also had anti-digestion stability in antioxidant activity. This study provides a theoretical basis for the application of MFBCO in natural antioxidant food.