Optimization of Fermentation Process and Study on Flavor Characteristics of Licorice Bingguo Wine

In this work, the fermentation process of Bingguo wine (BW) was systematically optimized using Bingguo fruit and licorice as raw materials. Single-factor tests combined with response surface methodology were adopted, taking alcohol content and sensory evaluation score as the core assessment indices. Volatile flavor substances in Bingguo, BW, and licorice Bingguo wine (BGW) were identified and quantified via gas chromatography-mass spectrometry (GC-MS). The discrepancies in volatile profiles and key odor-active constituents among the three samples were further explored by partial least squares-discriminant analysis (PLS-DA) and relative odor activity value (ROAV) analysis. The optimal technological parameters for BGW preparation were confirmed as follows: fermentation temperature of 20°C, fermentation time of 7 days, initial sugar content of 24 °Bx, and licorice supplementation level of 0.12%. Under these optimized conditions, the alcoholic strength of BGW reached 6.3% vol. In total, 335, 95, and 103 volatile components were identified in Bingguo, BW, and BGW, respectively. ROAV results demonstrated that ethyl hexanoate, ethyl acetate, and ethyl butyrate served as the shared key aroma-active compounds in both fermented wines. Significantly, the concentration of acetic acid in BGW was drastically elevated compared with that in BW, which endowed BGW with a unique sweet-sour taste profile that was clearly different from conventional BW.