Influence of grapes origin and yeast strain on aroma profile of corvina and corvinone dry passito wines

During wine production process high attention to the microbiological control from fermentation of the grape must to bottling is necessary. In fact, control of the indigenous microflora of the grape ensures correct fermentation activity of the inoculated starter, while control of the microorganisms in the finished wine is essential to prevent wine spoilage and to ensure the dominance of the desired bacteria when malolactic fermentation is required (Mas and Portillo, 2022).

Dada la importancia de los suelos y de los substratos geológicos en la zonificación vitivinícola, los autores realizan una revisión de estudios sobre las formaciones más importantes en la D.O. Jerez-Xérès-Sherry y Manzanilla-Sanlúcar de Barrameda.

In Portugal, the prospection and conservation of representative samples of intra-varietal variability of grapevine has been carried out for 46 years, and in 2010 an infrastructure was created for the conservation of all these genetic resources – the portuguese association for grapevine diversity (porvid) experimental centre for the conservation of grapevine diversity. the aim is to save the genetic identity of ancient varieties to prevent their imminent loss and to preserve the raw material for current and future selections, thus adding economic value and sustainability to the vine and wine sector.

Astringency is an important red wine quality attribute, which can be measured both chemically and sensorially. The use of tannin activity shows potential as a valuable chemical measurement in understanding red wine mouthfeel properties such as astringency and bitterness, which is also affected by tannin structural factors, in addition to matrix effects. Tannin activity is defined as the enthalpy of interaction between tannins and a hydrophobic surface. Studies involving tannin activity have been performed since the early 2010’s, but chemosensory studies used to evaluate how structure-activity relationships change across multiple, consecutive vintages are limited. The aim of this study is to investigate how tannin activity may be linked to red wine mouthfeel, and how all these variables may change according to wine age.

Fungal chitosan is a polysaccharide made up of glucosamine and N-acetyl-glucosamine and derived from chitin-glucan of Aspergillus niger or Agaricus bisporus. Fungal chitosan has been authorized as an antiseptic agent in wine since 2009 (OIV) and in organic wine in 2018. At the maximum dose of 10g/hl, it was shown to eliminate Brettanomyces bruxellensis, the main spoilage agent in red wines. Fungal chitosan is highly renewable, biocompatible (ADI equivalent to sucrose) and non-allergenic. However, winemakers often prefer to use sulfites (SO2), though sulfites are classified as priority food allergens, than chitosan. Indeed, many conflicting reports exist regarding its efficiency and its side effects towards beneficial wine microorganisms or wine taste. These contradictions could be explained by the heterogeneity of the fungal chitosan lots traded, the diversity of the wines (chemical composition, winemaking process), but also, by the recently highlighted huge genetic diversity prevailing in wine microbial species.