Raúl Domínguez-Perles

The objective of this work is the development of a new fermented beverage (‘kombucha’-like), enriched with broccoli by-products as an ingredient, a source of organosulfur compounds, which could be biotransformed into more bioaccessible, bioavailable, and bioactive metabolites. The new beverages have shown variations in the physicochemical (pH, 3.6–6.3; acidity, 0.65–1.39 g/L; °Brix, 4.63–8.20). Moreover, the phytochemical characterization has demonstrated different degrees of metabolization of the glucosinolates, leached during the infusion of the plant material into isothiocyanates (sulforaphane in concentrations up to 31.39 µg/100 mL) and its metabolic derivatives (sulforaphane-N-acetylcysteine in concentrations up to 5.37 µg/100 mL). Therefore, these results demonstrate that the increase in the concentration of the bioactive compounds concentration would provide higher bioavailability and health benefits. This is especially relevant with regard to anti-inflammatory activity. Reporting additional proof of enhanced biological benefits will boost the development of new functional beverages.

The by-products of grapes (Vitis vinifera L.) in the winemaking process present a diverse phytochemical profile of (poly)phenols, essentially represented by phenolic acids, flavonoids, and stilbenes, which have health benefits. In winemaking, solid (grape stems and pomace) and semisolid (wine lees) by-products are generated, negatively impacting the sustainability of the agro-food activity and the local environment. Although information on the phytochemical profile of grape stems and pomace has been reported, especially information concerning (poly)phenols, research on wine lees is necessary to take advantage of the compositional traits of this residue. So, in the present work, an updated, in-depth comparison of the (poly)phenolic profiles of these three resulting matrices in the agro-food industry has been carried out to provide new knowledge and interesting data on the action of yeast and lactic acid bacteria (LAB) metabolism in the diversification of phenolic composition; additionally, we extract complementarities for the possible joint application of the three residues. The phytochemical analysis of the extracts was carried out using HPLC-PDA-ESI-MSn. The (poly)phenolic profiles of the residues showed significant discrepancies. The results obtained showed that the greatest diversity of (poly)phenols was found in the stems of the grapes, followed closely by the lees. Through technological insights, it has been suggested that yeasts and LAB, responsible for the fermentation of must, might play a key role in the transformation of phenolic compounds. This would provide new molecules with specific bioavailability and bioactivity features, which might interact with different molecular targets and, consequently, improve the biological potential of these underexploited residues.