Effects Of Different Drying Methods On Selenium Species And Bioavailability In Cardamine Violifolia

Selenium（Se）is an essential trace element and its effective supplementation depends not only on the intake of Se but also on the bioavailability of each Se species in the body.As a Se-rich plant,Cardamine violifolia（C.violifolia）was approved as a food ingredient in 2021 and is a good dietary source of organic Se,however,there are few studies on the effects of different drying methods on the Se species and bioavailability in C.violifolia.Therefore,in this paper,the effects of different drying methods on the physicochemical quality,total polyphenols,total flavonoids,total Se,each Se specie and antioxidant activity of C.violifolia were investigated by using fresh C.violifolia as the research object,and the bioaccessibility and bioavailability of total Se and each Se specie in C.violifolia treated with different drying methods were studied by simulating human gastrointestinal digestive environment and Caco-2 monolayer cell model.The bioaccessibility and bioavailability of total Se and each Se specie in C.violifolia treated with different drying methods were investigated by simulating human gastrointestinal digestive environment and Caco-2 monolayer cell model.The main findings are as follows:The effects of five drying methods（far-infrared drying（FIRD）,vacuum drying（VD）,microwave vacuum drying（MVD）,hot air drying（HD）and freeze-vacuum drying（FD））on the physicochemical quality,total polyphenols content,total flavonoids content,total Se content,content of each Se specie and antioxidant activity of C.violifolia were investigated,and the correlations between antioxidant activity and different antioxidant components were analyzed.The results showed that the FIRD-treated samples maintained the green color and had the highest retention of total Se and organic Se,with 72.86%and 82.13%for leaves and 86.32%and 83.71%for stems,while the retention of total Se and organic Se in the VD,MVD and HD-treated samples were lower than 70%.Although the FD-treated samples had better microstructure,color and higher total polyphenol and total flavonoid contents,their total Se and organic Se retention rates were lower than 60%.the results of DPPH·,ABTS⁺·scavenging ability and ferric ion reducing ability indicated that the FIRD,FD and VD-treated samples had better antioxidant activity.The correlation results showed that there was a significant correlation between total Se content,total polyphenol content and antioxidant activity.The bioaccessibility of total Se and each Se specie in leaf of C.violifolia treated with different drying methods was investigated by simulating the human gastrointestinal digestive environment,and the results showed that the bioaccessibility of total Se in FIRD and MVD treated samples was higher than 75%;the bioaccessibility of total Se in VD,FD and HD treated samples was lower than 70%.The results of organic Se species（Se Cys₂,Me Se Cys and Se Met）showed that FIRD-treated leaf samples had the highest bioaccessibility,reaching 81.59%,71.79%and 84.59%,respectively,followed by MVD-treated leaf samples.The translocation rate and uptake rate of each Se specie in FIRD and MVD treated leaf of C.violifolia samples at different time periods were investigated by Caco-2 monolayer cell model.The results of the translocation rate showed that in the AP-BL direction,Se Cys₂ and Me Se Cys in FIRD-treated samples had the highest translocation rate at 90 min,8.12%and8.61%,respectively,and Se Met had a lower translocation rate,only 2.15%at 120 min;while the translocation rate of each organoselenium specie in MVD-treated samples was around 4%.The uptake rate results showed that in AP-BL direction,the uptake rate of organoselenium species in FIRD and MVD treated samples increased with time,where the uptake rate of Me Se Cys in FIRD treated samples was 39.54%,which was significantly（p<0.05）higher than Se Cys₂ and Se Met.The results of bioavailability of total Se and each Se specie in the dried samples of C.violifolia showed that the bioavailability of total Se in FIRD-treated samples reached 49.11%,which was significantly higher than that of MVD-treated samples.The bioavailability of inorganic Se specie was the lowest,and among the organic Se species,the bioavailability of Se Cys₂ was significantly lower than that of Me Se Cys and Se Met,among which,the bioavailability of organic Se in FIRD-treated samples of C.violifolia was significantly higher than that of MVD-treated samples.