The effect of vine variety and vintage on wine yeast community structure of grapes and ferments

Exploring the evolution of microbial communities from the phyllosphere and carposphere to the grape must of Vitis vinifera L. cv's Chardonnay and Pinot noir

Microbial communities associated with the grapevine phyllosphere and carposhere are a fundamental determinant of grape and wine quality. High throughput amplicon sequencing was used to profile the fungal and bacterial communities on the associated phylloplane and carposphere of Vitis vinifera L. cv's Chardonnay and Pinot noir in the Elgin and Hemel-en-Aarde wine districts of South Africa in the 2021-2022 growing season. The subsequent grape must was analysed to determine the prevalent microbiome. The most abundant bacterial and fungal genera found in both the phylloplane and carposphere of Chardonnay and Pinot noir were Pseudomonas and Filobasidium. The LEfSe (Linear discriminant analysis Effect Size) revealed significant differences in fungal and bacterial biomarkers from leaf, berry and grape must samples; however, no biomarkers were identified for cultivar nor location. Fungal β-diversity was significantly similar at different phenological stages, whereas bacterial β-diversity was significantly similar regardless of the site of colonisation. However, skin integrity of the grapes was may have influenced the microbial diversity.

Regional aroma characteristics of spontaneously fermented Cabernet Sauvignon wines produced from seven sub-regions in Shangri-La of China

Shangri-La is a promising wine region in China, which has great potential for producing high-quality wines with distinctive regional characteristics. In this work, the aroma properties of spontaneously fermented Cabernet Sauvignon wines produced from seven sub-regions of Shangri-La (Adong, Liutongjiang, Sinong, Xidang, and Nitong from Lancang River basin; Benzilan and Dari from Jinsha River Basin) were comprehensively analyzed using the headspace micro-extraction with gas chromatography-mass spectrometry, odor activity values, and olfactory evaluation. Results showed that a total of 59 volatiles belonging to seven groups were identified and quantified in all regional wines, with alcohols constituting the most abundant group, followed by esters and volatile fatty acids. Based on their odor activity values, six alcohols, seven esters, two terpenes, one C13-norisoprenoids, and three volatile fatty acids were identified as key volatiles which significantly contribute to the aroma of these wines. Principal component analysis showed the distinct compositions of these 19 key volatiles among the seven regional wines. Olfactory evaluation revealed certain differences in aroma profiles, particularly "Tropical fruit", "Dried fruit", "Vegetal", and "Sweet" among them. This study enhances our understanding on the unique terroir flavors of Shangri-La wines and is helpful for further producing high-quality wines with regional characteristics.