Enhancing flavour with non-Saccharomyces during vinegar alcoholisation: a mechanism study

The effects of mixed fermentation of non-Saccharomyces (Pichia fabianii, Kluyveromyces thermotolerans, and Saccharomycopsis fibuligera) with Saccharomyces cerevisiae on the physicochemical indexes and flavour of rice vinegar fermentation were studied. The mixed fermentation increased the activity of & beta;-glucosidase and esterification enzyme. The & beta;-glucosidase activity of P. fabianii was 1.6 times higher than that of S. cerevisiae alone, and the esterification enzyme activity was increased by about four times. Compared with the single fermentation of S. cerevisiae, the mixed fermentation of P. fabianii and S. cerevisiae increased the type and content of aromatic esters and produced ethyl acetate and phenethyl acetate. The mixed fermentation of K. thermotolerans and S. cerevisiae made an outstanding contribution to produce higher alcohols. Among them, the content of isobutanol and phenylethanol increased by nearly ten times; the content of isoamylol increased by more than eight times. S. fibuligera provides a unique flavour of phenols because of 2-methoxy-4-ethylphenol and 2-methoxy-4-ethylphenol.