藜麦芽发酵浓浆模拟体外消化及抗氧化活性研究

STUDIES ON SIMULATED IN VITRO DIGESTION AND ANTIOXIDANT ACTIVITY OF FERMENTED QUINOA MALT PASTE

目的研究发酵工艺和体外消化过程对藜麦芽浓浆营养物质及抗氧化活性的影响。方法借助体外模拟消化模型,对藜麦芽发酵浓浆进行消化,与未发酵浓浆对比,对蛋白质水解度、还原糖、多酚、黄酮含量进行测定。通过DPPH自由基、羟自由基、超氧阴离子自由基清除率以及铁还原能力和总抗氧化能力五种方法评价藜麦芽发酵浓浆的抗氧化活性。结果与未发酵样品相比,经过发酵的藜麦芽浓浆蛋白质水解度提高了23.28%,模拟小肠消化后再提高17.14%;经过发酵后,藜麦芽浓浆的快消化淀粉(rapidly digested starch,RDS)和慢消化淀粉(slow digested starch,SDS)含量分别增加了21.22%、5.14%,抗性淀粉(resistant starch,RS)含量减少26.23%;多酚与黄酮经过消化含量明显升高,在模拟小肠消化中升高最明显,尤其发酵浓浆的多酚得到充分释放。在抗氧化活性研究中,对未发酵组、发酵组和发酵消化组分别进行抗氧化实验,均表现出一定抗氧化活性,发酵组和发酵消化组抗氧化能力明显高于未发酵组,同时发酵消化组抗氧化活性最高。结论发酵可以提高藜麦芽浓浆的消化特性和抗氧化活性,经过消化后营养更易被吸收,且抗氧化活性增强。

Objective To study the effects of fermentation and in vitro digestion on nutrients and antioxidant activity of quinoa malt paste. Methods The quinoa malt paste was digested using an in vitro model of gastrointestinal digestion. The proteolytic degree, the contents of reducing sugar, polyphenol and flavonoids of the fermented paste were determined in comparison with unfermented paste. The antioxidant activity of the paste was evaluated by determining scavenging rates against DPPH radicals, hydroxyl radicals, and superoxide anion free radicals, as well as iron reducing ability and total antioxidant capacity. Results Compared with unfermented paste, after pepsin digestion, the protein hydrolysis of quinoa malt fermented paste increased by 23.28%, which was further increased by 17.14% following simulated intestinal digestion. Moreover, the rapidly digested starch （RDS） and slow digested starch （SDS） contents of the quinoa malt paste were increased by 21.22% and 5.14% respectively, and the resistant starch （RS） content decreased by 26.23%. The contents of polyphenols and flavonoids were increased significantly after digestion, and polyphenols showed the highest level in simulated intestinal digestion which may be due to full release during fermentation. Meanwhile, the antioxidant activity of the fermentation group and the digestion group was significantly higher than that of the unfermented group, and the digestion group was the highest. Conelusion Fermentation can improve the digestion and antioxidant activity of quinoa malt paste, and the nutrients are more easy to be absorbed after digestion with enhanced antioxidant activity.