PATTERNS OF PIGMENT CHANGES IN POMEGRANATE (PUNICA GRANATUM L.) PEEL DURING FRUIT RIPENING

Fruit color is one of the most important factors in marketing satisfaction. Pomegranate (Punica granatum L.) cultivars generally have fruit with colors ranging from green to red during ripening. An elite Chinese pomegranate cultivar ‘Taishanhong’ was picked at 7 stages and analyzed by HPLC to determine chlorophylls, carotenoids, and anthocyanins in the peels of fruit. The pigment patterns of fruit development at different stages were revealed. Total chlorophylls and carotenoids decreased during fruit maturation, while a continually increase of total anthocyanins occurred. After August 14, anthocyanin levels exhibited a rapid increase. With regard to carotenoids, represented by β-carotene and lutein, levels exhibited a constant decline except for an initial increase β-carotene concentration. Chlorophylls (chlorophyll a, chlorophyll b) decreased continuously until they almost disappeared. The temporal changes in chlorophyll a, chlorophyll b, and lutein during the color transition of the peel from green to red were very similar. Six anthocyanins including delphinidin 3,5-diglucoside (Dp3,5dG), cyanidin 3,5-diglucoside (Cy3,5dG), pelargonidin 3,5-diglucoside (Pg3,5dG), delphinidin 3-glucoside (Dp3G), cyanidin 3-glucoside (Cy3G), and pelargonidin 3-glucoside (Pg3G) exhibited varying patterns with time. The main concentration of Cy3,5dG (2.99 mg 100 g^-1) and Cy3G (3.10 mg 100 g^-1) presented significant differences during ripening period (p<0.05) compared with other four anthocyanins. The results indicated that the loss of green colour and the development of red coloration were due to an almost complete loss of chlorophylls and carotenoids, and an increase in anthocyanins. Cy3,5dG and Cy3G were the major anthocyanins in pomegranate peel.