In grapevine canopies, depending on canopy architecture, leaves and bunches can develop in conditions varying from heavily shaded to fully exposed. Studies on the effect of light exposure on specific phenolic compound and on the nutraceutical properties, evaluated as antioxidant activity, in seed and skin extract of Dolcetto grape cultivar are reported. Three levels of bunch exposure were carried out: fully exposed, middle shaded and heavily shaded. The grape was harvest at technological maturation during 2011 and 2012 vintage.
The response of total polyphenol, flavanol, anthocyanin contents and antioxidant activity to treatment conditions was variable an depend on the degree of bunch shading. Grapes that had developed on bunches receiving high levels of light ( fully exposed) for both years, showed a higher berry weigh and a higher number of seed per berry.
The seed extract from grape fully exposed, in both years, shows the lower phenolic content and the higher antioxidant activity. While the skin extract from heavily shaded, for both years, showed the higher phenolic content, but the antioxidant activity was higher only in 2011 year. The effects of light on quali-quantitative berry phenolic content are discussed.
Poster presented at Enoforum 2013, 7-9 May, Arezzo (Italy)