BIOSORPTION OF UNDESIRABLE COMPONENTS FROM WINE BY YEAST-DERIVED PRODUCTS

Current changes of ecoclimatic indicators may cause significant variation in grapevine phenology and grape ripening. Climate change modifies several abiotic factors (e.g. temperature, sunlight radiation, water availability) during the grapevine growth cycle, having a direct impact on the phenological stages of the grapevine, modulating the metabolic profile of berries and activating the synthesis and accumulation of diverse compounds in the skin of berries, with consequences on the composition of the grapes.
The influence exerted by different meteorological conditions, during three consecutive years (2020-2022) on secondary metabolites such as the polyphenolic profile of Grignolino grapes was investigated. The samples were collected from three vineyards characterized by different microclimatic conditions mainly related to the vineyard aspect and to a different age of the plants.

The wine market interest for autochthonous varieties, particularly from less known wine regions, has significantly raised in the past few years. In that context, Slovenia, a small country from central Europe with a long winemaking tradition, is getting more and more attention, particularly through its range of unique regional varieties. Among them, Zelen, meaning “green” in Slovene, can only be found in the Vipava valley region, located on the western side of the country, near the border with Italy. When they are young, Zelen wines display very singular aromas reminiscent of rosemary, sage and white fruit. Despite its uniqueness, Zelen wine aromatic typicality is poorly documented in the literature.

Post-harvest grape berries dehydration/withering are worldwide applied to produce high-quality sweet and dry wines (e.i., Vin Santo, Tokaji, Amarone della Valpolicella). Temperature and water loss impact grape metabolism [1] and are key variables in modulating the production of grape compounds of oenological interest, such as Volatile Organic Compounds (VOCs), secondary metabolites responsible for the aroma of the final wine.
The aim of this research was to assess the impact of post-harvest dehydration on free and glycosylated VOCs of two Italian red wine grapes, namely Nebbiolo and Aleatico, dehydrated in tunnel under controlled condition (varied temperature and weight-loss, at constant humidity and air flow). From these grapes Sforzato di Valtellina Passito DOCG and Elba Aleatico Passito DOCG, respectively.

During bottle aging, many thiol compounds are involved in the expression of bouquet of great aged red wines according to the quality of the closure.1,2 Identifying thiol compounds in red wines is a challenging task due several drawbacks including, the complexity of the matrix, the low concentration of these impact compounds and the amount of wine needed.3,4
This work aims to develop a new strategy based on the functionalisation of oak wood organic extracts with H₂S, to produce new thiols, in order to mimic what can happen in red wine during bottle aging. Following this approach and through sensory analysis experiments, we demonstrated that the vanilla-like aroma of fresh oak wood was transformed into intense “meaty” nuances similar to those found in old but non oxidized red wines.

Volatile compounds play a significant role on the organoleptic properties defining wines quality. This particular role was exploited in several studies with the aim to differentiate wines from a more or less extensive production area, according to their sensory profile [1], as well as their chemical composition [2,3] (Di Paola-Naranjo et al., 2011; Kustos et al., 2020). Indeed, since aroma compounds development in grapes depends primarily on the environmental conditions of the vines and grapes (soil and climate), it is conceivable that these parameters craft the aromatic signature of the wine produced, in relation to its origin (Van Leeuwen et al., 2020). In this work, a general study on the aromatic and sensorial profile of wines produced in five sub-regions of the Corbières denomination, a renowned red grape varieties viticultural region in South France, was reported.