“White” grapes are actually green in color, and are evolutionarily derived from the purple grape. Mutations in two regulatory genes of white grapes turn off production of anthocyanins, which are responsible for the color of purple grapes.
Red grapes are large and medium in size and are round to oblong in shape cylindrical or oval berries for some varieties, the smooth, glossy skin ranges in color from pale blush to deep red, and the skin is firm and crisp
Black seedless grapes are small to medium in size and are round to slightly oval in shape. Their skin is deep purple to nearly black, and some varieties may have a waxy bloom or film on the surface to prevent moisture loss. The skin is firm and does not slip from its flesh. The flesh is translucent, tender, and less crunchy than most red or green table grapes.