Juice quality and polyphenol concentration of fresh fruits and pomace of selected Nova Scotia-grown grape cultivars

Ratnasooriya, C. C., Rupasinghe, H. P. V. and Jamieson, A. 2010. Juice quality and polyphenol concentration of fresh fruits and pomace of selected Nova Scotia-grown grape cultivars. Can. J. Plant Sci. 90: 193-205. Juice, fresh fruit and pomace of 10 selected Nova Scotia-grown grape cultivars (five table and five wine cultivars) were evaluated for their physicochemical parameters and major phenolic compounds to determine their suitability in use for developing functional beverages. Colour intensity, total soluble solids, total anthocyanin concentration and antioxidant capacity were significantly higher in juice of wine grape cultivars than in juice of table grape cultivars. Titratable acidity was not significantly different among the juice of the two categories. In juice, a high positive correlation was observed between total phenolic concentration measured using Folin-Ciocalteu assay and antioxidant capacity measured using oxygen radical absorbance capacity (ORAC) (r=0.87) and ferric reducing antioxidant power (FRAP) (r = 0.95). Flavan-3-ols, stilbenes and anthocyanin concentrations were significantly higher in fruits of wine grape cultivars, while the distribution of flavonols was highly variable in two categories. The descending order of total phenol concentration in fruits was: Lucie Kuhlman > Baco Noir>Marechal Foch>Castel 19637>Sovereign Coronation>Leon Millot>Van Buren>Swenson Red>Suffolk Red>Reliance. The average overall concentrations of flavan-3-ols, navonols, stilbenes and anthocyanins ill pomace were 40, 90, 60 and 50% higher than that of the fresh fruits. Among the cultivars evaluated, Castel 19637 and Lucie Kuhlman showed the greatest potential for the development of a functional beverage; however, further characterization on sensory quality attributes is required.