1. Introduction
The color of a grape berry is determined by the quantity and composition of anthocyanins in its skin. It is known that red cultivars accumulate anthocyanins in their skins, whereas white cultivars do not synthesize them [1] and [2]. Anthocyanin compositions in grape cultivars have been studied by several researchers [2], [3] and [4]. Shiraishi and Watanabe [4] determined the anthocyanin compositions of 59 cultivars of red and black grapes and reported that most red cultivars contain mainly derivatives of the anthocyanidins cyanidin and/or peonidin, while black cultivars contain primarily delphinidin, petunidin, and/or malvidin derivatives.