Co-Fermentation of Wickerhamomyces anomalus and Saccharomyces cerevisiae in Bread Dough: Effects on Ethyl Acetate Production and Flavor Enhancement.

Fermentation affects the quality of bakery products. Saccharomyces cerevisiae is the traditional baking yeast, but the desire for alternative flavor profiles has driven interest in non-Saccharomyces yeasts. Wickerhamomyces anomalus, a non-Saccharomyces yeast with high ester-producing ability, has attracted attention as a promising co-fermentation partner. Although previous studies have explored its co-fermentation potential in alcoholic beverage production, the effects of its co-fermentation with S. cerevisiae on dough fermentation characteristics, bread quality, and flavor remain largely unexplored. The aim of this study was to evaluate the baking potential of W. anomalus strains isolated in Korean nuruk and to examine the effects of co-fermentation with S. cerevisiae on bread quality. Dough co-fermented with both yeasts showed improved leavening ability and distinct volatile compound profiles compared with single-fermented dough. Specifically, ethyl acetate levels were higher in co-fermented dough than in dough fermented only with S. cerevisiae. Among the strains tested, W. anomalus NIYL25845 exhibited gas production comparable to the control strain KCTC27761 and the highest ethyl acetate production during co-fermentation. Bread co-fermented with S. cerevisiae and W. anomalus NIYL25845 had a similar specific volume and texture to those of bread fermented with S. cerevisiae alone, although the co-fermented bread exhibited higher baking loss. The levels of esters and higher alcohols increased compared with the control (sole S. cerevisiae fermentation), and the ethyl acetate content reached 3.80 ± 0.54 ppm - the highest among all bread samples tested. These results suggest that co-fermentation with W. anomalus NIYL25845 is a promising strategy for enhancing bread flavor without compromising bread quality.