Phenolics and antioxidant activity in different cultivars/clones of Vitis vinifera L. seeds over two years

Grape seeds (GS) are one of the most important by-products of the winery and grape juice industry. GS contain a vast array of health-giving metabolites, including several polyphenols known for their remarkable antioxidant activity. In this study, it has been evaluated the nutraceutical potential of seeds from 15 grapevine cultivars/clones in terms of total phenols, monomeric, dimer, polymeric, gallate esters flavan 3-ols composition and in vitro antiradical activity. Considerable quali-quantitative differences in polyphenol content and AA had been observed among GS from different cultivars/clones collected in 2013 and 2014. In most of the investigated cultivars/clones, the better values of TP, FL and AA were recorded in GS collected in 2014. The polymeric procyanidins were significantly higher in 2014 in all the cultivars, while the gallate esters were significantly higher in 2013. These differences can be attributed to different climatic conditions in 2013 and 2014. In conclusion, the data here reported help to identify the best source of GS for the recovery of bioactive polyphenols and to valorize these waste materials.