Vegan fining strategies in Port wine: implications for chemical composition and One Health sustainability

Background: Wine fining is a critical step for stabilisation and clarification, traditionally relying on animal-derived agents such as gelatine. However, increasing regulatory, environmental and ethical concerns have driven the search for sustainable alternatives aligned with the One Health framework, integrating human, environmental and food system health [1-3]. Objective: This study aimed to evaluate the impact of vegan fining agents on the physicochemical, phenolic, volatile and elemental composition of different Port wine styles. Methods: Winery-scale fining trials were conducted using White, Tawny and Ruby Port wines. Two non-animal-based alternatives (pea protein and yeast-derived products) were compared with reference controls. Treatments were applied in triplicate (n=3) using 40 L stainless steel tanks. Wines were analysed according to official OIV methods, including basic physicochemical composition, colour and phenolic parameters, volatile compounds and elemental composition. Data were analysed by one-way ANOVA followed by Tukey’s HSD post hoc test, with significance set at p<0.05. Results: Fining effects were strongly matrix-dependent. In White wines, colour intensity and total phenolics were significantly reduced by gelatine, while vegan agents showed intermediate behaviour. In Tawny wines, most parameters remained stable, although total anthocyanins decreased significantly with protein fining, particularly for gelatine. In Ruby wines, fining treatments significantly reduced colour intensity and total phenolic index, with gelatine showing the strongest effect, while vegan treatments induced moderate changes. Volatile composition was only marginally affected, with minor variations in higher alcohols and esters, indicating limited sensory impact. Elemental composition remained largely unchanged across treatments, and cadmium showed no variability. Overall, observed differences were often statistically significant but of low oenological magnitude. Conclusions: Vegan fining agents demonstrated comparable performance to gelatine in maintaining wine quality while reducing reliance on animal-derived products. From a One Health perspective, these findings support the adoption of non-animal-based fining strategies as a sustainable alternative, minimising environmental impact and aligning with evolving consumer and regulatory expectations without compromising wine stability or composition.