Effects Of Lactobacillus Pentosus 124-2 On The Quality Of Sourdough Steamed Bread

Sourdough is a kind of starter with lactic acid bacteria and yeast as the main bacterial community.The steamed bread fermented by sourdough has a pleasant taste and long shelf life.Lactobacillus pentosus 124-2(L.pentosus 124-2)is a common strain in sourdough.This study used L.pentosus 124-2 and yeast to produce sourdough.In this study,yeast,L.pentosus 124-2,and sourdough were used as starters to study the effects of dough components,network structure forces,glutenin macropolymer structure,and disulfide bond on steamed bread quality during sourdough fermentation.The main research contents and results are as follows:(1)Effects of sourdough fermentation on dough quality and its components.Firstly,the differences in farinaceous and tensile properties of doughs with different starters were measured,and then the changes in HMW-GS and LMW-GS,free sulfhydryl groups and disulfide bonds,network space forces,and starch thermodynamic properties in doughs with different starters,and analyzed the effect of sourdough fermentation on dough components.The results show that compared with YSB dough,the degree of weakening of SSB dough was increased,and the elasticity and ductility were improved.The relative contents of 1Ax1 and 1Bx7+1By8 were the highest,indicating that the participation of L.pentosus 124-2 in fermentation can promote the enrichment of subunits that positively impact dough quality.The content of disulfide bonds and hydrogen bonds increased significantly,indicating that the sourdough fermentation made the gluten network structure more fully developed by changing the dough components to improve its physical properties.(2)The molecular weight distribution and composition changes of glutenin macropolymer in the fermentation process of different starter doughs were analyzed by SDS-PAGE and SE-HPLC.After fermentation,compared with YSB,the intensity of glutenin macropolymer electrophoresis bands was significantly weakened in SSB,the ratio of LPP and SMP decreased,and the ratio of SPP and LMP increased.FTIR results show that the ratio of random coils and ?-turns in the secondary structure of GMP increased significantly during sourdough fermentation,and the content of disulfide bonds in LSB and SSB was significantly higher than in YSB.It is shown that sourdough fermentation can improve the flexibility and hydration of dough by increasing the disorder and cross-linking degree of protein.(3)Taking steaming quality,sensory quality and storage quality of steamed bread as indicators,the effect of sourdough fermentation on the quality of steamed bread was studied.The results show that the sourdough fermentation significantly increased the specific volume,cohesion,whiteness,core density and porosity of steamed bread,significantly decreased the hardness,and improved the sensory quality of SSB.The results of steamed bread storage quality show that the texture deterioration rate,aging rate and moisture migration rate of SSB were lower than those of YSB,and LSB had the lowest aging rate and moisture migration rate,indicating that sourdough fermentation could inhibit the deterioration of steamed bread storage quality.