There is an increasing interest in the valorization of wine waste by-products. Grape pomace/marc can be an important source of polyphenols but also of polysaccharides (PSs). Therefore, the aim of this work was to extract PSs from grape pomace and musts and incorporate them into wines to improve their quality and valorize these residues. Two white wines were elaborated and treated with four different PS extracts obtained from white grape pomace, white must, a wine purified extract rich in RG-II, and commercial inactivated yeasts. In general, the use of grape PSs extracted from grape pomace or must improve some characteristics of wine, increasing the polysaccharide and volatile concentrations. These PS extracts can be useful to modulate some taste attributes such as an excess of acidity and bitterness and can also prevent the loss of volatile compounds associated with fruity and floral notes over time. This is the first study that shows the effects of grape polysaccharides on the chemical composition and sensory characteristics of white wines. Considering the obtained results, the grape pomace and surplus of musts can be considered valuable sources to obtain polysaccharide-rich products, opening a new opportunity to take advantage of by-products from the wine industry.

Background and goals In recent years, some wineries have started to use wooden vats again for fermentation and/or for the storage of wines because they have attractive advantages for wine quality; for example, the use of wooden vats for alcoholic and malolactic fermentation of red wines may enhance the varietal characteristics and increase the complexity of the wine. The goal of this work was to study the evolution of the volatile compounds during the aging of red wine in oak vats compared to oak barrels, and the correlation of volatile compounds with sensory characteristics after 12 months of aging. Methods and key findings The red wines were produced according to the usual winemaking process in the winery and aged for 12 months in new untoasted wooden vats, new barrels, one-year-old barrels, and two-year-old barrels for two consecutive vintages. Volatile composition and sensory analyses were carried out. Conclusions and significance The wines aged in new barrels had a greater loss of ethyl esters and acetates of alcohols, while those aged in vats maintained slightly higher concentrations of these compounds which are responsible for fruity and floral aromas. A strong correlation was found between the sensory data and the volatile composition of the wines aged for 12 months, clearly distinguishing the wines aged in vats from those aged in barrels. These wines were well discriminated by projective mapping sensory analysis, which is an effective and simple tool to differentiate wines.

Volatile compounds contribute to wine aroma and can interact with polyphenols, polysaccharides (PS), and proteins. This work evaluated the effects of adding different PS extracts obtained from winery by-products, must and wine on the volatile composition and sensory attributes of young red wines. These results highlight the effect of the wine matrix on the impact of PS on the volatile composition. The highest concentrations of volatile compounds were reached in wines with higher phenolic content and mainly those treated with PS extracts contained higher proportions of low-molecular-weight PS (55–68%). These PS extracts maintained high concentrations of compounds related to fruity and floral aromas, such as ethyl esters of fatty acids (8–23%), alcohol acetates (9–23%), and terpenes (11–43%). In addition, the PS extracts from winery by-products and wines improved taste sensations in young red wines, mainly those with high acidity, by reducing acidity, bitterness and astringency. Therefore, PS extracts obtained from by-products have the capacity to modulate the volatile composition and mouthfeel of red wines with high phenolic content, excess acidity or astringency.

Grape polysaccharide extracts derived from winemaking by-products have been shown to affect key wine characteristics. This study aimed to investigate the application of different grape-derived, polysaccharide-rich extracts and commercial yeast products in white sparkling wines, since no other studies have been found. The impacts of these products on the volatile, phenolic and polysaccharide compositions, as well as on the foam properties and sensory characteristics, were evaluated. After 15 months of aging, the products used did not influence the color and phenolic composition of the sparkling wines. However, they had a positive effect on the volatile compounds, with treated wines showing a general increase compared with the control, mainly in ethyl esters and alcohol acetates, compounds associated with fruity and floral notes. The treated wines showed clear sensory differences compared with the control, including aromatic complexity, which may reflect better preservation of certain aromatic compounds over time. In addition, improvements in wine taste were observed, likely due to a reduction in perceived acidity and bitterness. These results demonstrate the potential of grape-derived polysaccharide extracts to preserve volatile compounds in sparkling wines and to enhance their aromatic complexity and mouthfeel, thus improving overall sensory quality.