Microbial diversity of fermented dough and volatile compounds in steamed bread prepared with traditional Chinese starters

Abstract Steamed bread prepared by using sourdough as a fermentation starter is a traditional staple food in China. We used metagenomics-based gene amplicon sequencing to analyse the bacterial and yeast/mould diversity of fermented dough prepared with two kinds of traditional Chinese starters from Xinxiang (XX) and Heze (HZ). The results indicated that although Lactobacillus and Pediococcus predominated in both fermented doughs, the species and content of acid-producing bacteria in the HZ dough were greater than those in the XX dough, consistent with higher total acidity in the HZ dough compared to the XX dough. For the yeast/mould diversity, Saccharomycetales was dominant in both fermented doughs. Interestingly, in the HZ samples, 25.56% of the yeast/mould belonged to Hyphopichia. A larger number of volatile compounds were found in the samples prepared with traditional Chinese starters compared to the sample prepared with a commercial yeast (CY). These results indicate that microbial diversity plays a role in the construction of the physical and chemical properties of steamed bread, which is helpful for differentiating traditional Chinese sourdough starters and for industrially producing steamed breads.