Considering the increasing demand for the production of wines suitable for allergen-sensitised, vegetarian and vegan consumers, this study aimed to compare the effectiveness of commercialised vegetable proteins derived from pea and potato and the traditionally used fining agent (i.e., animal gelatine) at two different doses. Their ability to both remove monomeric, oligomeric, and polymeric flavanols that are involved in the wine astringency perception and preserve anthocyanins and colour characteristics was assessed.
PROJECT LAYOUT:
- Four young red wines (one wine for each variety, all belonging to vintage 2016) from Italian wineries were used in the present study for the fining trials: Primitivo, Montepulciano, Syrah, and Nebbiolo.
- The fining agents used in this study were four commercially available and allergen-free vegetal-derived protein extracts; two from pea (PE1 and PE2) and other two from potato (PT1 and PT2). The study also included one animal gelatine (GE).
- Wine fining trials were carried out in filled 1-L bottles where two different dosages (Low and High) were added for each fining agent to each wine.
- All fining experiments were carried out in triplicate, by setting for 7 d at 18 °C.
- Wines were filtered and subjected to chemical and sensory analyses.
RESULTS:
- Total phenolic compounds and flavanols – the fining agents reacted differently on the different cultivars in terms of efficacy in the removal of phenolic compounds. This study highlighted for the first time that both the effectiveness of vegetal-derived proteins and the target compounds are influenced by the wine phenolic composition.
- Total anthocyanins and colour parameters – anthocyanin losses in Primitivo and Nebbiolo wines, which are richer in cyanidin-3-glucoside than Montepulciano and Syrah, were higher after fining treatments with pea-derived proteins (PE1H and PE2H, respectively) whereas the lowest contents of anthocyanins corresponded to both GEH and PT1H treatments in Montepulciano and Syrah wines.
- Regarding vegetal fining agents, PT1 treatments (potato-derived protein) were the most effective in the reduction of flavanol compounds, followed by PE1 (pea-based protein). PT1 treatments removed flavanols in a relatively similar way to gelatine whereas PE1 formulation preserved coloured pigments better. An important aspect to consider is the strong influence of formulation for the potato-based fining agents (PT1 and PT2) because PT2 treatment caused only a minor removal of flavanols and few changes in colour parameters. Therefore, great variability in potato-based fining agents on the market can be assumed because of different sources, extraction conditions, extract preparation and possible protein hydrolysis. Undoubtedly, this leads to a different binding affinity and efficiency.
CONCLUSIONS:
This comparative study demonstrated the use of plant-based fining agents (pea and potato) as viable alternatives to gelatine to produce vegan-friendly, allergen-free wines. However, the results of this study strongly suggest the necessity of preliminary wine fining trials, possibly accompanied by phenolic and sensory analyses of the trial wines before large scale fining.
REFERENCE
RÃo Segade, S.; Paissoni, M.A.; Vilanova, M.; Gerbi, V.; Rolle, L.; Giacosa, S. Phenolic Composition Influences the Effectiveness of Fining Agents in Vegan-Friendly Red Wine Production. Molecules 2020, 25, 120. https://doi.org/10.3390/molecules25010120
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