Effect Of Lactobacillus Sanfranciscensis On The Structure Of Glutenin In Dough

Sourdough means a sour dough,which is a stable multi-strain fermentation system,and its microbial community is mainly composed of lactic acid bacteria,yeast and mold.Lactobacillus sanfranciscensis is one of the most dominant lactic acid bacteria in sourdough.In this research,a strain of L.sanfranciscensis Gm4 isolated from Chinese traditional sourdough was used as an experimental object to study its effect on the structure of glutenin macropolymer(GMP)and to conduct a genomic analysis.The main conclusions are as follows:First,in this research,L.sanfranciscensis Gm4 isolated from sourdough was used to ferment GMP solution.Meanwhile,L.plantarum and Saccharomyces cerevisiae,which are also the dominant bacteria in sourdough,were used as controls to observe the solubility of GMP,free thiol content,secondary structure changes.The results show that the effect of Gm4 on the secondary structure is obvious,making all the irregular coils in the protein converted into β-sheet and β-turn.L.plantarum,which is also a lactic acid bacterium,also observed similar results.While the effect of S.cerevisiae on secondary structure is weak.Within 6 hours of fermentation,Gm4 promoted the conversion of disulfide bonds to free sulfhydryl groups and depolymerized GMP.The content of free sulfhydryl groups after fermentation of S.cerevisiae was similar to Gm4,while L.plantarum promoted the conversion of free sulfhydryl groups to Sulfur bond.After 24 hours of Gm4 fermentation,the dissolution rate of GMP increased by 2.47%,lower than 7.06% of L.plantarum,which was similar to the results of S.cerevisiae.Subsequently,Secondly,Illumina Hiseq next-generation sequencing technology was used to sequence the genome of L.sanfranciscensis Gm4 and preliminary bioinformatics analysis.From the GO annotation results,it is found that in terms of biological processes,Gm4 has higher gene abundance in cellular process,single-organism process,and metabolic process;in terms of molecular function,gene abundance is higher in aspects such as membrane,membrane part,and cell;In terms of cellular components,binding and catalytic activity gene abundance is higher.It shows that it has a positive regulating effect in related metabolic processes.In the COG functional annotation,Translation,ribosomal structure and biogenesis have the highest gene abundance values,followed by Replication,combination and repair,Amino acid transport and metabolism,Nucleotide transport and metabolism,etc.