Optimization of fermentation process of original wine of mulberry spirit based on response surface method and quality analysis

In this research, the mulberry wine was prepared using mulberry as raw material, and then mulberry spirit was obtained by mulberry wine distillation. The fermentation process of original wine of mulberry spirit was optimized by single factor and response surface experiments and the physicochemical indexes were determined by conventional methods. The volatile flavor components contents in mulberry spirit were determined by gas chromatograph (GC). The key aroma components were screened by aroma activity values (OAV). The results showed that the optimal fermentation process conditions of original wine of mulberry spirit were obtained as follows: fermentation temperature 32 ℃, initial sugar content 24%, Saccharomyces cerevisiae addition 2%, and fermentation time 50 d. Under these optimized conditions, the ethyl lactate contents, alcohol content, total acid, total ester and soluble solids contents in original wine of mulberry spirit were 0.2 mg/L, 12%vol, 5.3 g/L, 5.9 g/L and 4.8 g/L, respectively. A total of 33 volatile flavor components were detected in mulberry spirit, including 9 alcohols, 7 acids, 15 esters, 1 aldehyde, and 1 ketone. There are 15 key aroma components (OVA>1), of which benzyl alcohol, phenethyl alcohol, ethyl acetate, ethyl caproate and ethyl lactate contributed more to the flavor of mulberry spirit.