Abstract: In order to enhance the flavor and texture of sourdough steamed bread, this study analyzed the growth, fermentation and aroma production characteristics of Saccharomyces cerevisiae XTC-y11 and XTC-m13, Cyberlindnera jadinii HSO-y3, which had been isolated from sourdough, and S. cerevisiae CICC 31616 and evaluated the sensory quality and volatile flavor compounds of steamed bread made with each of these strains. The results revealed that XTC-y11 grew at the fastest rate. XTC-y11 and XTC-m13 had better sugar metabolism than the other strains. Compared with S. cerevisiae CICC 31616, XTC-y11 produced more gas, and XTC-m13 resulted in a larger expansion volume of dough, showing higher fermentation capacity. The total ester concentration of the fermentation broth of HSO-y3 at 24 h was highest (1.672 g/100 mL). The whiteness, hardness, chewability and elasticity of steamed bread with XTC-y11 or XTC-m13 were moderate. The results of sensory evaluation showed that steamed bread with XTC-y11 or XTC-m13 scored highest. Altogether, 37 volatile components were identified in the four steamed breads by gas chromatography-ion mobility spectrometry (GC-IMS), with the predominance of alcohols and esters. 4-Pentenoic acid, 2-methylbutyraldehyde, (E)-2-hexenoic acid, ethyl lactate, ethyl acetate and 2-amylfuran were predominant in steamed bread with XTC-y11, while esters were predominant in steamed bread with HSO-y3. Using partial least square-discriminant analysis (PLS-DA), we found significant differences in volatile components among the four steamed breads, and identified 18 differential compounds. In summary, XTC-y11 had a positive effect on the flavor and quality of steamed breads. This study provides a favorable reference for improving the quality and flavor of steamed bread.

Key words: yeast; fermented dough; fermentation characteristics; volatile flavor components; steamed bread