Mixed Fermentation with Wickerhamomyces anomalus and Saccharomyces cerevisiae Improved the Quality of Steamed Bread

In this study, Saccharomyces cerevisiae and non-Saccharomyces strains were isolated from sourdough. S. cerevisiae SQJ20, which had a stronger gas-producing capacity than commercial activated dry yeast, was selected from 78 strains of S. cerevisiae. Wickerhamomyces anomalus GZJ2 and Torulaspora delbrueckii SDJ6 were selected to improve the quality of steamed bread. Co-fermentation with S. cerevisiae SQJ20 and W. anomalus GZJ2 at a ratio of 1:2 significantly improved the quality of steamed bread. Furthermore, W. anomalus GZJ2 increased the contents of total protein and free amino acid (13.69%), with the increase being greatest in the sweet amino acid proline (94.69%), the aromatic amino acid phenylalanine (82.63%), and the essential amino acid lysine (66.26%). The electronic nose and sensory evaluation results corroborated that the addition of W. anomalus GZJ2 improved the quality of steamed bread. In conclusion, co-fermentation with S. cerevisiae SQJ20 and W. anomalus GZJ2 could improve the quality of steamed bread without extending the fermentation time. Our observations provide a reference for the industrial production of flavored steamed bread.