Winemaking Characteristics of Four Longan Varieties from Luzhou Based on Organic Acids, Amino Acids and Flavor Compounds

This study investigated the winemaking characteristics of four common longan varieties (Shixia (SX), Lidongben (LDB), Rongyu (RY), and Fenglisui (FLS)) in Luzhou, Sichuan province, aiming to facilitate the utilization of medicinal and culinary resources and advance the development of the fruit deep-processing industry. By determining basic physicochemical indicators, organic acid contents and amino acid profiles during fermentation, as well as volatile flavor compounds, electronic nose (E-nose) response patterns, and sensory attributes of the finished wine, we found significant varietal differences in fermentation characteristics and final product quality. SX exhibited superior fermentation performance, with the highest ethanol production, moderate organic acid levels, and significant amino acid utilization. In terms of product quality, LDB wine contained higher organic acid contents, conferring it a more pronounced sour note, while RY wine was rich in umami and sweet amino acids, contributing to its umami and sweet flavor profile. A total of 246 volatile compounds were identified across all wine samples, among which 29 had an odor activity value (OAV) < 1, including phenethyl alcohol, 1-pentanol, ethyl acetate, ethyl octanoate, ethyl decanoate, methyl salicylate, phenethyl acetate, and octanoic acid. These compounds, collectively imparting fruity and floral aromas, were common to all varieties. Notably, Shixia wine exhibited significantly higher concentrations of alcohols and esters compared with the other varieties (P < 0.05). E-nose analysis demonstrated significant differences in sensor responses for S1 (ammonia and amines), S4 (alcohols and organic solvents), S10 (alkanes and combustible gases), and S11 (aromatic compounds) among the four varieties (P < 0.05). In sensory evaluation, Shixia wine achieved the highest overall score, with prominent wine-like and fruity aromas. Correlation analysis showed significant positive correlations between the contents of esters and total volatile substances and aroma characteristics (P < 0.05). This study validates the superior winemaking potential of the Shixia longan variety, offering insights for the high-value utilization of medicinal and culinary resources in fruit wine production.