Effects Of Probiotic Fermentation On Dough Properties And Steamed Bread Quality

Steamed bread is welcomed by the most Chinese people because of its soft taste and economic benefits.Based on the fermentation advantages of probiotics and the demand of contemporary consumers for healthy food.The present study chooses three species of probiotics with better fermentation performance（saccharomyces cerevisiae,Lactobacillus plantarum,and Lactobacillus rhamnosus）to prepare the probiotics yeast,including saccharomyces cerevisiae（SC）,saccharomyces cerevisiae combined with Lactobacillus plantarum（SCLP）,saccharomyces cerevisiae combined with Lactobacillus rhamnosus（SCLR）.The optimum fermentation process of probiotic on steamed bread was determined by single factor and orthogonal experiments.Compared with ordinary commercial yeast,the properties of dough such as stretching,rheology,the secondary structure of protein and internal microstructure were measured.The water migration and antioxidant properties during dough fermentation were also analyzed.The effects of probiotics on specific volume,texture,sensory score,internal microstructure,flavor content,digestive characteristics,and antioxidant characteristics of the fermentation steamed bread were also explored.In addition,the effect of probiotic fermentation on the aging of steamed bread was evaluated by measuring the changes of hardness and elasticity,the migration of water,and the recovery of starch aging during storage.The tensile properties,rheology,secondary structure of protein and internal microstructure of the dough were measured.The moisture migration and antioxidant properties of the dough during fermentation were also analyzed.Then the effects of probiotics on steamed bread specific volume,texture,sensory score,internal microstructure,flavor substance content,digestive properties and antioxidant properties were investigated.Finally,the effects of probiotic fermentation on the aging of steamed bread were evaluated by measuring the changes of hardness and elasticity,the migration of water and the aging recovery of starch during storage.Firstly,the results showed that the best preparation processes of three probiotic steamed bread,consisting of SSC（SC fermented steamed bread）,SLP（SCLP fermented steamed bread）,and SLR（SCLR fermented steamed bread）were as follows:probiotic solution 4×10¹⁰cfu,fermentation time 1h,proofing time 60 min.Secondly,compared to the ordinary commercial yeast fermented dough（DAQ）,the probiotic fermented dough DS（SC fermented dough）,DLP（SCLP fermented dough）,DLR（SCLR fermented dough）changed the secondary structure of gluten protein and increased the content ofβ-corner,while decreased the content ofα-helix.Meanwhile,it also improved the rheological properties of dough,reduced the tensile resistance of dough,and increased the extension distance.In addition,probiotic fermentation also increased the content of total phenol,enhanced the scavenging ability of DPPH free radical,increased the reducing power,and reduced the water migration rate in dough.Among them,the content of total phenol in DLP is the highest（38.45μg/g）,DPPH radical scavenging was the strongest（72.03%）,and the reducing power was the best.Then,compared with common commercial yeast steamed bread,probiotic fermentation improved the specific volume and the texture characteristics of steamed bread.Among them,the specific volume of SLP is the best（2.33 m L/g）,and SLR showed the best texture characteristics;the digestive characteristics of steamed bread were reduced,the antioxidant properties were improved,and the sensory scores were higher in steamed bread after probiotic fermentation.In addition,54 flavor substances were found in four kinds of fermenting steamed bread.Among them,40 flavor substances were found in SLR,37flavor substances were found in SLP,33 flavor substances were found in SAQ,and 26flavor substances were found in SSC.Finally,by analyzing the quality and structure of steamed bread in the process of storage,the moisture migration and starch aging recovery situation analysis showed that probiotics steamed bread were hardness,slower elasticity change rate,and lower moisture migration rate than ordinary plain wheat roll,however,the surface of desiccation and internal slag phenomenon is not obvious.The starch aging enthalpy value with the extension of storage time were increased,but the rate of starch aging enthalpy value was lower than ordinary bread.the rising rate of it was as well.Therefore,the probiotic fermentation bread could slow down the aging of steamed bread.