Aroma Compounds Characteristics of Buckwheat Sourdough Steamed Bread Fermented by Mixed Culture of Weissella confusa and Wickerhamomyces anomalus

A mixed culture of Weissella confusa,a lactic acid bacteria(LAB)isolated from Jiugui wine starter and Wickerhamomyces anomalus,an aroma-producing yeast isolated from Meilanchun liquor were used to study the effect of fermentation on flavor compounds in buckwheat sourdough steamed bread. The symbiosis of the two strains was explored by measuring the growth curve of the strains. The difference in flavor compounds of the mixed fermentation(MBF),single bacteria fermentation and buckwheat steamed bread was compared by using SPME-GC-MS and rapid nasopharyngeal Heracles Ⅱ technology. The results showed that the number of LAB in MBF reached 9.38 log CFU/g,while the yeasts reached 8.51 log CFU/g,thus the two strains had a good symbiotic relationship. The main characteristic flavor compounds of buckwheat sourdough after fermentation were ethanol,acetic acid,ethyl acetate,acetoin and isoamyl alcohol. Compared with the single yeast fermented buckwheat sourdough steamed bread,the content of the esters in steamed bread with MBF increased from 5.27% to 9.53%,combined with ROAV analysis,the flavor intensity of mixed culture fermentation was significantly higher than that of single lactic acid fermentation and single yeast fermentation,which gave the steamed bread a stronger aroma and fruit aroma. Sensory evaluation confirmed that steamed bread with MBF had the highest overall acceptance compared to the other groups.