Insight into the effect of geography and variety on the wine flavory distinctness based on the variations of indigenous microbiota in Xinjiang of China

Abstract

Wine fermentation and flavour formation are the result of complex biochemical reactions driven by the microbial activity at the influences of multiple scales, of which the regional distinctness is significantly affected by the specific microbiota. In the study, volatile profiles and fungal compositions were examined by analysis of HS-SPME-GC-MS and high-throughput amplicon sequencing. The results indicated that succinic acid levels were significantly altered by regional factor, while tartaric acid, lactic acid, and volatile acidity were significantly affected by varietal factor. A total of 71 volatiles was characterized and quantified in the resultant wines. Chemometric approaches (OPLS-DA and Random Forest clarification) were used to identify the key regional variations of volatiles from different varietal wines. Nine of the key volatiles were clarified in Cabernet Sauvignon wines, including 1-propanol, isoamylol, (E)-3-hexen-1-ol, 1-heptanol, phenylethyl alcohol, ethyl isovalerate, ethyl 2-methylbutanoate, diethyl succinate, and phenethyl acetate, while seven of the regional variations across Marselan wines were identified involving 1-octen-3-ol, 1-heptanol, ethyl acetate, isobutyl isovalerate, diethyl succinate, d-limonene, and nerol. The microbial amplicon-based result showed that the genera of Saccharomyces, Hanseniaspora, Aspergillus, and Cladosporium, were predominant on grape epidermis and during spontaneous fermentations, of which the relative abundances were adjusted by region, subregion, and variety. Correlation analysis highlighted that several non-fermentative fungi were significantly associated with aroma-active compounds with the exception of fermentative yeasts. This study underscores the intricate interplay between regional factors and varietal characteristics in shaping wine aroma characteristics, highlighting the importance of microbial diversity in enhancing wine quality and uniqueness.

Keywords: Flavour distinctness; Microbial diversity; Red wine; Subregion; Volatile compounds; Xinjiang.