Analyses of functional components of grapes and grape products

Abstract

In this study, various functional components of grapes and grape products were analyzed. Resveratrol and ellagic acid, representative components of polyphenols found in grapes, were analyzed using high-pressure liquid chromatography. Relatively higher contents of resveratrol in seedless grapes and ellagic acid in Muscat Bailey A (MBA) grapes were found compared to those in other grape cultivars. Total polyphenols and total flavonoids were significantly higher in 'Campbell Early' grape varieties. A comparison of the antioxidant activity showed that the DPPH and ABTS scavenging activities of the MBA grape varieties were significantly higher. Among the grape products, wine had higher contents of the functional components than grape juice, particularly, red wine, which had higher content than white wine due to the differences in the manufacturing and fermentation processes. Grape juice contained higher contents of functional components in the concentrated form (100%). Some varieties contained relatively higher functional components compared to other antioxidants (acorbic acid, trolox). In conclusion, grape is considered an excellent antioxidant fruit with representative food color.