Fungi diversity and volatile in spontaneously fermented Cabernet Sauvignon wines: Insights into four sub-regions Penglai's Terroir

Abstract

Numerous studies have demonstrated a link between wine characterization and the regional microbial community in a large geographical region, but few have addressed the composition of microbial communities within smaller geographical regions and their impact on wine aroma. This study aimed to investigate differences in fungal communities during the fermentation of winemaking grapes in sub-regions within 30 km, as well as the terroir characteristics of regional wines. High-throughput sequencing identified Colletotrichum and Alternaria as the predominant fungi in the grape mash, with substantial microbial composition differences among sub-regions. During fermentation, Saccharomyces and Hanseniaspora emerged as key contributors, influencing alcoholic fermentation and preserving vineyard-specific characteristics. VPA results highlighted that fermentation substrates, organic acids, and fermentation products jointly propel the microbial community dynamics in Cabernet Sauvignon fermentation, achieving an explanation degree of 93.70–98.00 %. A total of 64 volatile compounds were identified across the wines, with ethyl acetate, 1-propanol, 2-methyl-1-propanol, 3-methyl-1-butanol acetate, 2-hydroxy-propanoic acid ethyl ester, 2-methyl-propanoic acid, phenylethyl alcohol showing significant inter-regional differences. Based on OAV values and distribution frequencies, 11 volatile compounds were determined as characteristic aroma compounds of the Penglai region, aligning with the outcomes of sensory evaluation. The relationship between fungal flora diversity and wine chemistry indicated that the predominant species during fermentation had a significant impact on the volatile composition of wine. This research enhanced our comprehension of the distinctive terroir flavors in Penglai regional wines, facilitating the further production of high-quality wines with local characteristics.