Comparison of the effect of exopolysaccharide-producing lactic acid bacteria from sourdough on dough characteristics and steamed bread quality

The use of exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) is promising in sourdough fermentation. However, the knowledge of the effects of various species of LAB on steamed bread making remains limited. In this study, the effects of two LAB with high EPS-producing capacity, namely Weissella cibaria L32 and Lactobacillus brevis L17 on dough fermentation and steamed bread quality were estimated. The addition of these two LAB strains significantly increased the titratable acidity and protease activity during the dough fermentation, especially L. brevis L17. Although the in situ EPS synthesised by LAB could improve the steamed bread quality, excessive acidification of L. brevis L17 would still increase the protease activity and thus destroy its gluten network structure. As a result, the steamed bread fermented with L. brevis L17 had the lowest specific volume and hardest texture in comparison with the steamed bread fermented with W. cibaria L32 and with added EPS produced by W. cibaria L32 and L. brevis L17. These results indicated that different EPS-producing LAB exhibited distinctive dough fermentation characteristics, and the in situ EPS-producing W. cibaria L32 could improve steamed bread quality, which confirmed its potential application in steamed bread making.