Valorisation of by-product-derived polysaccharides as a sustainable strategy to improve the sensory profile of wine

Abstract

The agri-food industry generates large amounts of coproducts and by-products that represent valuable resources for developing sustainable and innovative solutions. Among these, plant-derived polysaccharides have attracted attention due to their ability to interact with polyphenols and modulate sensory perception. Astringency, a key mouthfeel attribute in wine, is mainly associated with interactions between polyphenols and oral components such as salivary proteins and oral epithelial cells. This work aimed to evaluate the potential of polysaccharides derived from agri-food by-products as modulators of wine astringency through different molecular mechanisms.

Two complementary approaches were used. First, a highly astringent red wine from northern Portugal was supplemented with grape skin polysaccharides and aged for nine months, with effects assessed via physicochemical analysis and polyphenol–salivary protein interactions. Second, a red wine extract model was combined with citrus-derived pectic polysaccharides. Their influence on interactions between polyphenols and oral components was evaluated using in vitro oral models containing salivary proteins, oral epithelial cells (HSC-3 cell line), mucin and mucosal pellicle. Polyphenol adsorption and changes in salivary protein family interactions were analysed to better understand the mechanisms involved.

Polysaccharides reduce wine astringency by limiting interactions between polyphenols and salivary proteins. In an oral model, all fractions decreased polyphenol adsorption, especially at higher concentrations. They also modulated binding with key salivary proteins (proline-rich proteins, statherin/P-B peptide, cystatins). Their effectiveness depends on structural traits like molecular weight and uronic acid content, likely enhancing hydrogen bonding with phenolics and reducing interactions with oral surfaces.

Ackowledgements

This work was financed by national funds from FCT – Fundação para a Ciência e a Tecnologia, I.P., under the scope of the project UID/50006/2023 of the Associate Laboratory for Green Chemistry-LAQV REQUIMTE and by the project STrengthS4WineChaiN (NORTE2030-FEDER-01786100).

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