The Effects Of Lactobacillus On The Quality Of The Sourdough Steamed Bread And Its Starch Digestibility

Chinese steamed bread is one of the traditional staple foods in China,and it has been appreciated by the consumers due to its unique flavor,taste and eating-quality.Currently,the production of the domestic market steamed bread took the yeast as the starter,resulting flavor and odor are far from that of traditional sourdough steamed bread.Microbial colony in traditional sourdough starter containing yeast and Lactobacillus,and metabolism of lactobacillus can improve the quality and flavor of steamed bread.However,because of the complexity of the sourdough fermentation and the microbial content of uncontrollability,microbial fermentation process to nutrient digestion is more difficult to control in dough,especially starch digestion.Therefore,In this paper,the lactobacillus with strong fermentation ability and moderate acid production ability,was isolated from the traditional sourdough,yogurt and pickles.The quality and starch digestibility of steamed bread fermented by commercial yeast powder and the lactobacillus were measured to study the effect of lactobacillus fermentation on the quality and starch digestibility of steamed breadThe main contents of the paper are as follows:(1)A Lactobacillus named WX 2-10 was isolated and rescreened from traditional sourdough,yoghurt and pickle.Then through the 16S rDNA sequence analysis,the results showed that the WX 2-10 belonged to the genus of Lactobacillus planetarium.(2)The influence of lactobacillus on the quality of streamed bread were studied.In this study,steamed bread fermented by commercial yeast powder(angel yeast)and the lactobacillus(Lactobacillus plantarum)were studied for their sensory evaluation scores,texture parameter and antioxidant properties.The result shows that the streamed bread by adding lactobacillus has very big positive impact on the sensory evaluation,structure parameters and antioxidant properties.Lactobacillus a can improve specific volume of the steamed bread,and make the streamed bread more flexible and looser,and its taste and texture being better than the dry yeast streamed bread.This is a theoretical basis for adding lactobacillus to increase steamed bread quality and the ability of antioxidant.(3)Effect of lactobacillus on the starch digestibility(in vitro and in vivo)of streamed bread were studied.Steamed breads fermented by commercial yeast powder and the lactobacillus were studied for their starch digestibility.Starch digestion in vitro showed that the sugar yield of steamed bread fermented by lactobacillus was lower than yeast steamed bread after starch degradation.In vivo experiments,the blood glucose level and the area under the blood sugar curve of the human body was more lower and stable than the yeast steamed bread.In conclusion,the steamed bread fermented by lactobacillus has higher nutritional value than the yeast steamed bread,and the postprandial glycemic index rises slowly,which is more conducive to the control of blood sugar and the maintenance of post-prandial satiety.The excellent performance of lactobacillus fermented steamed bread is achieved by changing the size of starch,increasing the degree of starch polymerization,resistant starch(RS)content and amylose content to inhibit the activity of a-amylase,and delay the postprandial blood sugar.However,it did not change the functional group structure of starch molecules,nor did it produce new substances...