Study On The Antioxidant Effect Of Fermented Barley ?-glucan

?-glucan is an important functional factor in barley.The results of the previous study showed that the structure and function of barley?-glucan were changed after fermentation by Lactobacillus plantarum dy-1,but the effect on its antioxidant activity was not clear.Therefore,this paper focused on the physicochemical properties and in vitro antioxidant effect of barley?-glucan during dy-1 fermentation,and further explored the effect of dy-1 fermentation on the antioxidant effect of barley?-glucan in vivo and the possible mechanism of action,using Caenorhabditis elegans as a test model.The main study contents and results was as follows:1.Effect of L.plantarum dy-1 fermented barley on the basic physicochemical properties and in vitro antioxidant activity of?-glucan.Determination of molecular weight,rheology and in vitro antioxidant activity of barley?-glucan at different fermentation times.The results showed that dy-1 fermentation degraded the molecular weight of barley?-glucan from 1.052×10⁵ Da to 4.965×10⁴ Da within 0?24 h.The water-and oil-holding properties of barley?-glucan increased significantly with the increase of fermentation time,and the fluid viscous behavior of barley?-glucan increased and the elastic characteristics decreased at 6%concentration.The in vitro antioxidant activity of barley?-glucan before and after fermentation,and the hydroxyl radical scavenging activity and total antioxidant capacity of FRAP increased with the increase of fermentation time,but decreased significantly up to 32 h of fermentation.2.Effect of barley?-glucan on the in vivo antioxidant effect of nematodes before and after fermentation.To investigate the effects of FBG(fermented barley?-glucan)and RBG(raw barley?-glucan)on nematode growth and movement indices,in vivo antioxidant enzyme activity and longevity under oxidative stress conditions.The results showed that both FBG and RBG improved the growth index,locomotor behavior,mean survival rate and mean lifespan of nematodes;the effect of RBG treatment on the improvement of SOD enzyme activity and ROS level was better than that of FBG,while the effect of FBG treatment on the improvement of MDA content and mean lifespan in nematodes was better than that of RBG.3.Effect of barley?-glucan on the transcriptome of nematodes before and after fermentation,and transcriptome sequencing of H₂O₂-induced nematodes using RNA-Seq.The results showed that FBG mainly suppressed the calcium signaling pathway through the expression of Cyp-D gene and promoted the Wnt signaling pathway through the upregulation of GSK-3?gene to improve the oxidative damage in nematodes,while RBG mainly suppressed the calcium signaling pathway through the expression of ANT-solute carrier family 25 gene and promoted the lifespan regulation pathway through the downregulation of hsp-12.6 gene to improve the nematode.In the process of arachidonic acid metabolism,gene C03H5.4 was down-regulated by FBG and up-regulated by RBG.4.Effect of barley?-glucan on the metabolome of nematodes before and after fermentation and co-regulation mechanism.Screening and identification of differential metabolites involved in the regulation of FBG and RBG by metabolomics under oxidative stress conditions,and combined with transcriptomic data for combined KGML analysis.The results showed that the difference between FBG and RBG on the regulation of oxidative stress in the organism was mainly reflected in the arachidonic acid metabolic pathway;the gene C03H5.4 and the metabolites Leukotriene B4(Leukotriene B4)and Leukotriene A4(Leukotriene A4)were significantly down-regulated by FBG,and the metabolites PC(16:0/16:0)and 14,15-DiHETrE were significantly upregulated.