Effects Of Lactic Acid Bacteria On Sourdough Fermentation And Chinese Steamed Bread

We separated16strains lactic acid bacteria(LAB) from different sourcessourdough． These16strains were directly used in Chinese steamed breadproduction，then sensory the evaluation，By a series of identification，filtering thetwo higher rated LAB DN812and DM616，respectively：Lactobacillus planetariumand Streptococcus thermophilus．These two LAB used in Chinese steamed bread sourdough，to study the effectof LAB on sourdough properties.Studies have shown that the sourdoughfermentation force before the upward trend reaching a certain value and then adownward trend in36hours．Adding Streptococcus thermophilus，Lactobacillusplanetarium and yeast mixed fermentation in the sourdough the size of4hours toreach the peak of495mL；2hours gas production when the first reached themaximum956mL；its gas production up to3172mL at36hours．The mixturefermentation is superior to only add yeast sourdough single bacteria and yeastfermentation of the sourdough， the sourdough to hold gas also significantlyimproved， indicating that the mixed bacteria help to improve sourdoughfermentation power．With the extension of the fermentation time，the sourdough of adding LABacidification than only add yeast sourdough；sourdough moisture content，wateractivity and reducing sugar changes have some degree of volatility；wash out thegluten content are downward trend and basically not to wash the gluten content ofthe fermented sourdough after fermentation20hours；previous period yeast dominantof the fermented sourdough then LAB dominant of the fermented sourdough withthe extension of the fermentation time．After steaming bread cooling1hours，the determination of indicators of theChinese steamed bread and then by a sensory score comprehensive evaluation insourdough.At8hours， adding Streptococcus thermophilus， Lactobacillusplanetarium and yeast dough and then by modulation of steaming bread of sensoryevaluation scores up to93．Place in the refrigerator after3days，the index of height to diameter ratio，specific volume and whiteness of resteamed Chinese steamed bread and the steamed bread just steaming out shows general tendency．But the indicators of resteamedbread relatively small and the hardness was significantly larger．Chinese steamed bread began to mildew when stored at10days in roomtemperature，the degree of moldy even more serious as the fermentation time toextend；Chinese steamed bread which adding LAB have lesser mold degree thanthose not adding LAB，the instruction shows that to add LAB the Chinese steamedbread can extend the shelf life．...