Effect Of Chitooligosaccharide On Protein Degradation And Metabolism In Beer Barley During Malting

Chitooligosaccharide is a kind of natural active oligosaccharide.Studies have shown that chitooligosaccharide plays a significant role in promoting seed germination,plant growth and enhancing plant resistance.Shell oligosaccharides can promote the dissolution of malt and barley germination,for the study of shell oligosaccharides for dissolution and metabolic activity of protein in beer barley,based on the different concentration and average molecular weight of shell oligosaccharide processing beer barley,determine the protein dissolved in the process of system of wheat and barley,hydrolysis enzyme activity,antioxidant activity and metabolite changes,to assess the effects of a shell oligosaccharide on barley germination process.A total of 5 different average molecular weight chitosan oligosaccharides(1k Da,2k Da,3k Da,5k Da,7k Da)and 5 concentrations(0.02%,0.04%,0.06%,0.08%,0.1%)were selected as variables in this paper.Samples were taken at different time points in the wheat making process.The crude protein content,total nitrogen content and soluble nitrogen content during barley germination were determined.The addition of chitooligosaccharide could significantly improve the dissolution of barley protein,and the protein synthesis effect was most significant when the concentration was 0.04% chitooligosaccharide(3k Da)at 24 h.Chitosan oligosaccharide(3k Da)solution with a concentration of 0.06% has the most significant effect on protein dissolution.The chitosan oligosaccharide concentration of 0.06% can effectively improve the activity of barley protease and xylanase,and the chitosan oligosaccharide concentration of 0.02% has the most significant effect on the activity of alpha-amylase,beta-amylase and cellulase.Low molecular weight chitosan oligosaccharide can significantly increase the activity of alpha-amylase and beta-amylase.The content of total phenols in malt was increased by adding chitosan oligosaccharide(3k Da)at the concentration of 0.04%.The content of catechin,epicatechin,ferulic acid and eugenic acid in malt was increased by HPLC.DPPH,ABTS and FRAP were used to investigate the effects of chitosan oligosaccharide on the antioxidant activity of barley during germination.The results showed that chitosan oligosaccharide promoted the accumulation of maltol compounds and enhanced its antioxidant activity.The study on malt metabolism level was conducted to track the organic acid level in barley germination.The addition of chitosan oligosaccharide at 2 h had an effect on ketoglutaric acid,pyruvate,tartaric acid and lactic acid,and at 10 h had an effect on citric acid,lactic acid,pyruvate and glyoxylic acid.The addition of chitooligosaccharide can significantly increase the content of auxin,show a growth advantage,and inhibit the production of gibberellin and abscisic acid.