Grape seed extract: the first protein-based fining agent endogenous to grapes

Abstract

Background and Aims There is a growing interest in finding alternative wine fining agents to replace potentially allergenic animal‐derived and plant‐derived proteins. In this context, the potential use of grape‐derived fining agents would be beneficial as they would not introduce additional, potentially allergenic products to the finished wine. In this project, grape seed flour, a by‐product of the grape oil seed industry, has been used to prepare a grape seed extract (GSE) for testing as a novel wine fining agent. Methods and Results The fining performance of GSE was compared with that of patatin, pea proteins, polyvinylpolypyrrolidone and potassium caseinate in a white and in a rosé wine, and of ovalbumin and gelatin in a red wine. Reduction of turbidity, effect on wine colour, the concentration of phenolic substances, browning potential and wine sensory attributes were determined. Grape seed extract was effective in decreasing white wine turbidity when compared to potassium caseinate. In red wine, GSE removed some anthocyanin and proanthocyanins, while wine colour was only slightly affected. The greatest GSE effect was observed on the sensory properties of the treated wines, as it strongly reduced the vegetal notes in the rosé wine and improved the overall taste of the red wine as a result of the reduction in both acidity and astringency. Conclusions Grape seed extract can be considered a valid allergen‐free alternative to the most common wine fining agents. Significance of the Study Grape seed extract is the first effective fining agent endogenous to grapes, thus not attracting the legal restrictions concerning the presence of foreign substances.

Phenolic Composition Influences the Effectiveness of Fining Agents in Vegan-Friendly Red Wine Production

“…In the present study, the removal of flavanols during wine fining was similar to or even higher than that previously published for the use of gelatin, potato-based proteins (about −9% for PRO using both patatin and gelatin at 10 and 30 g/hL dose, FRV ranging from −1.1% to −13.9% for patatin and from −7.1% to −18.8% for gelatin at 10 and 30 g/hL [6]), and pea-derived proteins (−6.8% for PRO at 10 g/hL dose [8]; −3-5% of catechin and epicatechin and −15-22% of oligomeric proanthocyanidins at 20 g/hL dose [18]). The effectiveness of GEH fining agent to remove oligomeric and polymeric flavanols is undoubted as this treatment reduced PRO and FRV contents more than vegetal-derived proteins in Montepulciano and Nebbiolo wines, which are richer in polymeric proanthocyanidins, and was highly effective in Primitivo and Syrah wines.…”

“…One pea-based fining agent had an effect comparable to gelatin (animal origin) on the removal of polymeric flavanols with a minor loss of anthocyanins and therefore better preserving the wine color in terms of intensity and hue. For Primitivo, Montepulciano, and Syrah wines, even though there was a formulation-dependent effect, vegetal proteins gave more balanced reductions in terms of target phenolic compounds contributing to astringency and color perception.Molecules 2020, 25, 120 2 of 20 isolated from cereals, legumes, potatoes [6,7], seaweeds, grape seed extracts [8,9], and yeasts [10,11]. Other vegetal non-proteinaceous products, such as polysaccharide-based agents isolated from cell wall material of fresh apples and grapes or their respective pomaces, have shown great potential for wine fining purposes [12][13][14][15].Focusing on protein-based fining agents, they can have a different affinity to different types of phenolic compounds.…”

“…In the Raboso red wine, a reduction in some anthocyanins (−1.0-4.0%) and proanthocyanidins (−3.2-5.9%) was observed, similarly to other animal-and vegetal-derived fining agents tested, without markedly affecting wine chromatic characteristics (less than −5%). Nevertheless, the most important impact of GSE corresponds to the sensory attributes, reducing the vegetal notes in the Raboso rosé wine and both acidity and astringency in the Raboso red wine [8]. The dosages used were 5, 10, and 20 g/hL of GSE, corresponding respectively to 2.2, 4.4, and 8.7 g/hL of protein.Despite the effort made by various research groups in relation to the use of vegetal proteins as wine fining agents, few have been commercialized until now.…”

“…Molecules 2020, 25, 120 2 of 20 isolated from cereals, legumes, potatoes [6,7], seaweeds, grape seed extracts [8,9], and yeasts [10,11]. Other vegetal non-proteinaceous products, such as polysaccharide-based agents isolated from cell wall material of fresh apples and grapes or their respective pomaces, have shown great potential for wine fining purposes [12][13][14][15].…”

Clarification of apple juices with vegetable proteins monitored by multiple light scattering

“…For instance, pea and soy proteins have been applied in red wine (Ben, Mouls, Fulcrand, Douieb, & Hajjaj, ; Kang, Niimi, & Putnam Bastian, ). In addition, other protein sources have been investigated, such as potato (Gambuti, Rinaldi, Romano, Manzo, & Moio, ), grape seeds extract (Gazzola, Vincenzi, Marangon, Pasini, & Curioni, ), or enzymatically and chemically hydrolyzed wheat gluten (Maury, Sarni‐Manchado, & Cheynier, ).…”