Antioxidant Properties and Correlation with Chemical Components in Selenium-Enriched Rape Powder

This work aims to study the in vitro antioxidant activity of selenium-enriched rape powder extract and its correlation with basic chemical components. The results showed that compared with regular rape powder extract, selenium-enriched rape powder extract contained more nitrogen compounds, polyphenols, flavonoids, total selenium and polysaccharide-bound selenium, and had higher Fe3+ reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation, and hydroxyl free radical scavenging activity. Correlation analysis showed that the antioxidant activity was positively correlated with nitrogen compounds, total sugar, polyphenols, flavonoids, saponins, polysaccharides, total selenium, and polysaccharide-bound selenium. Partial correlation analysis showed that the antioxidant activity was only significantly or highly significantly positively correlated with polysaccharides and polysaccharide-bound selenium, which indicated that the difference in antioxidant activity between the two rape powder extracts may be mainly caused by the differences in polysaccharides and polysaccharide-bound selenium contents. In conclusion, there are differences in the basic chemical compositions of selenium-enriched and regular rape powder extracts, and selenium-enriched rape powder extract has a higher in vitro antioxidant activity. Polysaccharide-bound selenium was the major antioxidant component.