Abstract:

In this study, three aroma-producing yeast strains were screened from traditional fermented foods, Chongqing
pickled cabbage and Yangzhou bean paste. The characterization of these strains was also investigated for colony
morphology, ester-producing ability, carbohydrate utilization rate, dough fermentation ability and tolerance to high sugar
concentrations. The strain YG28B identified as Pichia guilliermondii by ITS rDNA sequencing was proved to have a huge
application potential. Preliminary studies on bread fermentation and baking application using YG28B indicated that bread
products showed good aroma when fermented with commercial dry yeast and YG28B cooperatively. The content of volatile
flavor substances as determined by GC-MS also showed a general rise in bread fermented by the combined starter cultures,
which displayed more attractive flavor when compared with that fermented by commercial dry yeast alone. This aromaproducing
yeast will have potential applications in baked products for improving the flavor of bread.

Key words: traditional fermented food, aroma-producing yeast, screening, fermentation ability, bread