Nutraceutical value of yellow- and red-fleshed South African plums (Prunus salicina Lindl.): evaluation of total antioxidant capacity and phenolic composition.

Alet Venter,Elizabeth Joubert,Dalene De Beer

doi:10.3390/molecules19033084

Abstract

Ten South African plum cultivars and selections, including yellow- and red-fleshed plums from two harvest seasons were evaluated in terms of nutraceutical value (phenolic composition, total polyphenol content (TPC) and total antioxidant capacity (TAC)) and fruit attributes (colour, fruit mass, etc.). Plums were evaluated at two maturity stages, i.e., directly after harvest (unripe) and after a commercial cold storage and ripening regime (ripe). The phenolic composition of South African plums varied greatly, both qualitatively and quantitatively, between cultivars and selections. Neochlorogenic acid, cyanidin-3-O-glucoside and quercetin-3-O-glucoside were the predominant hydroxycinnamic acid, anthocyanin and flavonol, respectively, although not present in all plums. The flavan-3-ols, (+)-catechin, (−)-epicatechin and procyanidins B1 and B2, were present in all plums. Red-fleshed plums tended to display higher TAC and TPC than yellow-fleshed plums. The flavan-3-ol content was highly correlated with TAC. The effect of harvest season was cultivar-dependent, but cultivar differences were not obscured. In terms of maturity stage, the ripe fruits tended to contain higher levels of anthocyanins and some flavonol compounds, although the TPC and TAC were not affected in most cases. South African plums, especially the red-fleshed selections PR04-32 and PR04-35, were shown to provide generally high TAC and TPC compared to literature values.

Highlights

Plums grown in South Africa for the fresh fruit market are classified as Japanese plums (Prunus salicina Lindl.)
Plum fruit (Prunus salicina Lindl.) from a range of yellow- and red-fleshed cultivars and selections were harvested during the summer of 2010/2011 (December 2010 to February 2011; first harvest season) and 2011/2012 (December 2011 to February 2012; second harvest season) (Table 1)
The red-fleshed selections PR04-32 and PR04-35 have especially high nutraceutical value, i.e., higher total antioxidant capacity (TAC) and TPC than some commercial cultivars, this was due to a high flavan-3-ol content and not linked to their flesh colour

Summary

Introduction

Plums grown in South Africa for the fresh fruit market are classified as Japanese plums (Prunus salicina Lindl.). Japanese plums differ from European plums (Prunus domestica L.) in various aspects such as size and composition of volatile compounds, sugars, organic acids and phenolic compounds [1,2]. The antioxidant activity of phenolic compounds is believed to contribute to the health benefits of plums [11]. Due to the nutritional and nutraceutical value of plums, it has been suggested as an important fruit to incorporate into the diet [5]. Interest in the nutraceutical value of foods has guided plant breeders to select genotypes for further evaluation based on phenolic content and antioxidant activity [12]

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