Analysis of microbial diversity of traditional Chinese starters and screening of special flavor yeast for Chinese baked flatbread

Introduction: Traditional Chinese starters have unclear microbial complexity and community functions. Methods: To screen functional yeasts for flavor enhancement of Chinese baked flatbread (CBF), Saccharomyces cerevisiae Y4 was isolated and identified from traditional Chinese starters using a combined approach of high-throughput sequencing and culturomics. The traditional starters samples were aseptically collected from Luohe, Xinxiang in Henan province and Rizhao in Shandong province. Results: The analysis of microbial communities revealed that Luohe starter had the highest fungal (Chao1 = 271.86) and bacterial (Chao1 = 341.76) richness, with dominant genera including Saccharomyces and Lactiplantibacillus. Saccharomyces cerevisiae Y4 showed the following performance: saturated gas production at 48 h, 12% ethanol tolerance, high acid tolerance (OD value below 0.15), and 1975 mL gas production in fermented dough. CBF fermented by Y4 had a high sensory score (82.8) and 40 volatiles, including the unique 1-octen-3-ol and a prominent level of phenethyl acetate content. Discussion: In this study, a superior yeast strain was identified, providing theoretical insights and valuable microbial resources for optimizing the flavor of CBF.