Abstract:
In order to investigate the effect of fermentation with different lactic acid bacteria (LAB) on the digestibility and sensory characteristics of steamed bread, four LAB starter cultures,
Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus rhamnosus, and
Lactobacillus reuteri were respectively employed for sourdough preparation. Commercial yeast was subsequently added for further fermentation and steamed bread production. The fermentation time, organic acid content, and inhibition rate of α-amylase in sourdough were investigated. Additionally, a comparative analysis was performed on the in vitro starch digestibility, simulated in vitro fermentation products, and sensory attributes of the steamed bread. The results showed that the sourdough fermented by
L. plantarum and
L. fermentum took a shorter time to reach pH 4, thereby exhibited a higher fermentation efficiency; the
L. fermentum sourdough contained the highest acetic acid content, and the
L. rhamnosus sourdough contained the highest lactic acid content. All the 4 sourdoughs showed an inhibitory effect on α-amylase activity. The inhibition rate of
L. fermentum sourdough is more than 2 times than that of other sourdoughs, reaching approximately 15.13%. In vitro starch digestion test indicated that the starch digestibility of
L. reuteri steamed bread was higher than that of white steamed bread, whereas the digestibility of steamed bread fermented by other LAB was significantly lower; the proportion of rapidly digestible starch in
L. fermentum steamed bread was 13.51%, which was 0.40 times that of white steamed bread; the proportion of resistant starch was 64.29%, which was about 1.70 times that of white steamed bread. In vitro fermentation test showed that
L. plantarum steamed bread was more effective in increasing the amount of intestinal short-chain fatty acids(SCFAs) compared to others;
L. fermentum showed the best effect on the proliferation of intestinal probiotics. Sensory characteristic analysis revealed that
L. fermentum and
L. reuteri improved the specific volume and texture of steamed bread more significantly than other cultures. The overall sensory evaluation of steamed bread fermented with
L. rhamnosus,
L. reuteri, and
L. fermentum was superior to that of white steamed bread, with
L. fermentum demonstrating a significant enhancement in the structure of the steamed bread and the electronic nose showed that its flavor was more unique. Additionally, the result of electronic tongue indicated that
L. rhamnosus steamed bread had a more distinctive salty and umami taste.