Wine-makers use sulfites in various steps of winemaking, from fermentation to bottling. However, sulfites have been connected to human health problems, and despite the various attempts to replace or minimize their levels in the winemaking process, no significant and widely used commercial process with marketable proof has appeared so far. In recent years, significant efforts to produce healthier wines has led to the replacement or reduction of the addition of sulfites, using alternative substances or techniques. Resveratrol and related biophenols seem to be of great interest, since beyond their protective nature and contrary to sulfites they can positively affect consumer health (Kontaxakis et al., 2020). These bioactive phytochemicals are naturally produced in grapes as evolutionary acquired mechanisms against pathogens and UV irradiation. The research team of the Department of Agriculture, of the Hellenic Mediterranean University, in collaboration with «Alexakis SA» and «Domaine Paterianakis» wineries, investigated the possibility of replacing the addition of sulfur dioxide (SO₂) by natural antioxidants. The addition of two concentrations of trans-resveratrol (30 and 60 ppm) and two concentrations of a mixture of phenolic substances extracted from winemaking by-products (60 and 120 ppm) was examined. Natural antioxidants were used as alternatives to the additional use of sulfuric anhydride after the fermentation in white (Vilana, Assyrtiko) and red (Kotsifali, Mantilari) wines. The effect on the antioxidant capacity and the physicochemical characteristics of the wines was studied during their storage for one year in the bottle. Classical wine analyses (OIV), determination of total phenolic components and determination of the antioxidant capacity of the wines (Rivero-Pérez et al., 2008; Waterhouse, 2001) were carried out to evaluate the effectiveness of the treatments in maintaining the quality of the wines. The addition of natural antioxidants, as an alternative to the addition of sulfuric anhydride, affected the characteristics of the wines, increasing the antioxidant capacity and the content of total phenolic components. The addition of natural antioxidants limited the quality degradation of the wines, limiting the volatile acidity in the wines to a degree proportional to the amount added. The winetasting evaluation of the experimental wines, it emerged that the addition of phenolic substance extracts affected the taste and aroma of the wines in a manner similar to a prolonged extraction during the fermentation period. In conclusion, the addition of antioxidant substances extracted from winemaking by-products can limit the need to add sulfuric anhydride to protect wines during their maturation and ageing.

120 wine samples were studied of 4 Cretan varieties (Assyrtiko, Vilana, Kotsifali, Mandilari) provided by 2 wineries (Alexakis and Paterianaki winery). The maturation process achieved with the addition of alternative antioxidants (phenols of 60 ppm and 120 ppm, resveratrol of 30 ppm and 60 ppm). The wine sampling took place over a period of 4 months, 8 months and 12 months during the years of 2019 and 2020.