Fruit anthocyanin profile and berry color of muscadine grape cultivars and Muscadinia germplasm

Abstract

Anthocyanin content and composition and CIE 1976 (L*, a*, b*) color space (CIELAB) color coordinates were examined for the skin of 22 muscadine grape (Vitis rotundifolia Michx.) cultivars and Muscadinia Planch germplasm. Analysis of berry skin extracts by high-performance liquid chromatography (HPLC) determined that anthocyanin content varied from less than 100 μg·g-1 in bronze and pink berries to over 5500 μg·g-1 in highly pigmented black berries. The anthocyanins delphinidin, cyanidin, petunidin, pelargonidin, peonidin, and malvidin were detected in their 3,5-diglucosidic forms. Analysis of berry color with a colorimeter revealed chroma (C*) ranged from 2.4 to 22.8 with the highest values occurring in bronze- and red-colored berries. As anthocyanin concentration increased, lightness (L*) decreased to a low of 20 to 23 in black-colored berries. Pink and red skin colors were primarily a result of lower levels of total anthocyanins, although there was also a shift away from delphinidin and petunidin production toward more cyanidin and peonidin. Malvidin, the most important anthocyanin for muscadine wine and juice color stability, was only abundant in a few clones, all of which had V. munsoniana (Simpson ex Munson) Small or V. popenoei (Fennell) Small in their pedigree. The interspecific hybrid 'Fennell's 3-way Hybrid' had the largest proportion of malvidin, contributing ≈58% of the total anthocyanin content. This clone also had low levels of delphinidin and high total levels of anthocyanin, making it a promising source for the improvement of muscadine grape pigment profiles.