Analysis of ester-producing performance in high-yield ethyl hexanoate yeast and the effect on metabolites in bio- enhanced Daqu, the starter for Baijiu and other traditional fermented foods.

Abstract

Ethyl hexanoate, one of the key flavor compounds in strong-flavor Baijiu. To improve the content of ethyl hexanoate in strong-flavor Baijiu, a functional strain with high yield of ethyl hexanoate was screened and its ester-producing performance was studied. Upon identification, the strain was classified as Candida sp. and designated as ZY002. Under optimal fermentation conditions, the content of ethyl hexanoate synthesized by ZY002 can be as high as 170.56 mg L-1. A fermentation test was carried out using the ZY002 strain bioaugmented Daqu to verify the role of the strain applied to Baijiu brewing. It was found that strain ZY002 could not only improve the moisture and alcohol contents of fermented grains but also diminish the presence of reducing sugar and crude starch. Furthermore, it notably amplified the abundance of flavor compounds. In this study, Candida sp. ZY002 with a high yield of ethyl hexanoate provided high-quality strain resources for the actual industrial production of Baijiu.