Sulphur dioxide (SO2) is widely used in the wine industry for its antioxidant and antimicrobial properties. European Union regulations limit SO2 content in red and white wines to 150 mg/L and 200 mg/L, respectively, while the World Health Organization recommends a daily intake limit of 0.7 mg per kg of body weight. Due to health concerns, there is a growing demand for wines with reduced or no SO2. To address this, the industry is exploring alternatives such as chemical methods, antioxidant substitutes, non-thermal technologies, and bioprotection with non-Saccharomyces strains.
The use of stilbenes as an alternative to sulphur dioxide
Stilbenes, a type of phenolic compound, are being studied as potential SO2 replacements due to their antioxidant properties. These compounds are found in winemaking waste, particularly vine shoots, which are rich in trans-resveratrol and ε-viniferin. Research has demonstrated that stilbene extracts from vine shoots can serve as effective wine preservatives. For example, commercial vine shoot extract (Vineatrol®) has been used successfully in red and white wines to improve colour, sensory characteristics, and storage stability.
The objective of the research
The study aimed to promote sustainability by using raw vine shoot extracts without further purification to reduce costs. The objective was to assess the preservative properties of this raw extract as a substitute for SO2 in rosé (Sangiovese) and red (Negramaro) wines. The study analysed the impact on the wines’ colour, phenolic content, volatile compounds, and sensory profiles at bottling and after three, six, and 12 months compared to wines with SO2.
Results
- The vine shoot extract increased trans-resveratrol, catechin, and gallic acid levels.
- It was positively correlated with procyanidin dimers in red wine, suggesting increased polymerisation.
- The extract provided less antimicrobial protection than SO2, as shown by higher ethyl phenol levels.
- It offered different oxidative protection, with less protection against anthocyanin degradation but better protection against carbonyl formation and oxidation of phenolic acids.
- Sensory analysis indicated that the extract enhanced the sensory profile of both wines, with a preference after 12 months of storage.
Conclusions
Vine shoot extract could be combined with reduced doses of SO2 in wines, mitigating issues related to SO2 use and offering a sustainable use for winemaking by-products. Further research is needed to optimise dosages and application stages.
Reference
Noviello, M., Antonino, C., Gambacorta, G., Paradiso, V.M., and Caponio, F. (2024). Use of vine-shoots stilbene extract to the reduction of SO2 in red and rosé Italian wine: Effect on phenolic, volatile, and sensory profiles. Heliyon, Published: July 08, 2024, DOI: https://doi.org/10.1016/j.heliyon.2024.e34310
Image: Pexels
