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), antioxidant
activity (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.
