Bioactive compounds and functional potential of Uapaca kirkiana (Muell. arg.) fruits

A Chawafambira,A Mpofu,Mc Achilonu,Mm Sedibe

doi:10.18697/ajfand.93.19660

A Chawafambira, A Mpofu + Show 2 more

Open Access

https://doi.org/10.18697/ajfand.93.19660

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Abstract

Consumption of Uapaca kirkiana indigenous fruit by the local populace is growing in popularity because of the acclaimed health and functional benefits. The aim of the study was to determine the bioactive compounds and functional properties of the U. kirkiana fruit. Besides the fruit’s pulp yield, the bioactive phytochemical constituent, physicochemical properties and functional characteristics of the pulp were analysed. The sugar, starch, minerals, and ascorbic acid constituents of the fruit pulp were, respectively determined using the following instruments: brix refractometer, megazyme kit, inductive coupled plasma-optical emission spectrometer and 2,6- dichlorophenolindophenol (DCPIP) titration test. The total phenolic content (TPC), tannin, and flavonoid contents were evaluated using Folin Ciocalteau test, tannin binding test and vanillin test, respectively. The average weight of the U. kirkiana fruits harvested from three regions having different climatic conditions ranged from 23.56 to 34.20 g per fruit. The mean pulp weight was from 12.15 g/100 g to 15.09 g/100 g per fruit. The biochemical and functional parameters obtained include total titratable acid (0.3 - 0.48 g/kg), antioxidantactivity (34.96 - 36.68%), vitamin C (15.74 - 16.63 mg/100 g), dry matter content (28.81 - 29.38%), pH (4.3 - 4.6) and sugar content (20.29 - 21.87 g/100 g). Fructose was the dominant sugar (10.12-11.0 g/100 g). Preliminary phytochemical screening of the pulp indicated the presence of tannins, flavonoids, amino acids and carbohydrate content. Total phenolic content ranged from 67.0 to 82.5 µg GAE/g. The essential elements constituent evaluation of the pulp revealed that Fe content was 11.3 - 12.2 mg/100 g, K (383.07 - 439.8 mg/100 g), Mg (28.7 - 35.1 mg/100 g), Ca (16.4 - 17.3 mg/100 g), P (13.4 - 15.1 mg/100 g), Na (9.08 - 9.78 mg/100 g), Cu (0.8 - 0.94 mg/100 g) and Zn (0.87 - 0.94 mg/100 g). This study, besides establishing U. kirkiana fruit as a good source of micronutrients (Fe, Cu, Zn), reveals that the fruit is also an excellent source of phenolic compounds, vitamin C and sugars, hence use as a dietary supplement may combat some nutritional deficiencies. We, therefore, recommend U. kirkiana fruits to be used to produce nutritive functional foods with health benefits such as probiotic jams and as an additive. Key words: Indigenous fruit, micronutrients, phenolic, pulp, phytochemicals, U.kirkiana, megazyme kit

Highlights

Uapaca kirkiana belongs to the genus Uapaca of the family Euphorbiaceae and subfamily Phyllanthaceae [1, 2]
Pulp weight recorded in Zimbabwe were lower than the pulp yield of 28.3 g/100 g in U. kirkiana fruits obtained in Tanzania as reported by Ndabikunze [6]
The Tanzanian fruits were pulped using a mechanical fruit pulping machine as compared to a manual process used in Zimbabwe, the low pulp weights/ yield observed in this work

Summary

Introduction

Uapaca kirkiana belongs to the genus Uapaca of the family Euphorbiaceae and subfamily Phyllanthaceae [1, 2]. The U. kirkiana plant is an underutilized indigenous fruit tree (IFT) found in the Miombo ecological zone in sub-Saharan Africa. Uapaca kirkiana was found to be the most preferred indigenous fruit tree among consumers and farmers [1]. The underprivileged and vulnerable groups of the society in drier regions of the sub-Saharan Africa are known as intensive consumers of wild fruits. The fruit is noted to be a good source of sugar, protein, and energy for the local consumers [6, 7]. Studies have confirmed that the fruit contains water (58.0-72.6 %), carbohydrates (28.7 %), proteins (0.1-0.5 %), fat (0.3-0.4 %), calories (523 kcal /100 g) and serves as a good source of Fe, Zn, Ca and K [6, 7]. Owing to diverse species of U. kirkiana, caused by differences in soil quality and varying environmental conditions, the indigenous plant has wide-range of functional properties as well as rich phytochemicals [6]

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