Diversity of anthocyanins and other phenolic compounds among tropical root crops from Vanuatu, South Pacific

Abstract

To study the composition and amounts of phenolic compounds in ten tropical root crop species consumed daily worldwide and particularly in South Pacific, acidified aqueous extracts were analyzed. Among 134 samples, 78 components were found. Among total peaks detected from these fractions, 3 anthocyanins (peonidin-caffeoyl-feruloylsophoroside-5-glucoside, petunidin-3-glucoside and pelargonidin-3-glucoside), 5 flavonols (hyperoside, isorhamnetin-3-glucoside, kaempferol-3-glucoside, quercetin-3-glucopyranoside and quercetin-3′-glucoside,6′-acetate), 3 flavanols (catechin, epicatechin and epicatechin-3-gallate), and 3 phenolic acids (caffeic acid, chlorogenic acid and 3,5-dicaffeoylquinic acid) were tentatively identified by HPLC-DAD. Although many compounds remain to be identified, results suggest that these tropical root crops are good sources of anthocyanins and phenolic compounds. The greater yam ( Dioscorea alata) had the highest anthocyanin content (up to 93.3 mg CGE/100 g DW), while taro ( Colocasia esculenta) had the widest range of flavonols (up to 326.7 mg QGE/100 g DW). Cultivars of these staples should be exploited in breeding programs for the development of varieties with enhanced health and nutritional benefits.