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ABSTRACTAnnona muricata L. (soursop fruit) is a seasonal plant with bio-geographical distribution in tropical and subtropical climates. This study evaluated the proximate, phenolic, and antioxidant properties of different parts of soursop fruit. The influence of oven and solar drying on phenolic and antioxidant activities of extracts (pulp, seed, and peel) were assessed. Proximate analysis on different parts of the soursop fruit showed the pulp to have high carbohydrate (32.9% ± 0.3) and moisture (19.1% ± 1.0). The seeds however contained higher crude fat (37.5% ± 1.2) and protein (25.0% ± 0.1) contents. Total phenolic content of the seeds (8.7 mgGAE g−1 ± 0.1) was higher than that of the pulp and the peel (8.6 mgGAE g−1 ± 0.1). The solar-dried fruit parts demonstrated superior antioxidant activity to the oven-dried parts. Extracts from the solar-dried soursop fruit samples, especially the seed, can serve as useful therapeutic ingredient for diet supplementation and could also be exploited for its high oil and protein contents.

ABSTRACTThis study aimed to evaluate the physicochemical properties of okra residue obtained after pectin extraction from three okra genotypes (Asha, Balabi, and Agbagoma). The okra residue was oven-dried. Proximate analysis and functional properties were determined using standard AOAC methods, whereas mineral content was determined using atomic absorption spectroscopy. Phenolics and antioxidant capacity were determined using the Folin-Ciocalteu and DPPH methods. The okra pectin extraction residues were rich in carbohydrates (70.0–71.7%) and ash (19.55–21.9%), but had relatively low proteins (0.87–3.62%) and moisture (4.71–5.94%) contents. The okra residue samples had high potassium (8.59–9.27 mg/100 g) and sodium (.380–3.93 mg/100 g) contents. The solubility index for the varieties ranged from 18% to 25%, whiles swelling power ranged from 8% (Balabi) to 10% (Asha). The pectin extraction by-products showed high water absorption (546% to 617%) and oil absorption (216% to 318%) capacities. Residues from all okra genotypes demonstrated antioxidant activity (7.13–15.15%) and contained varied amounts of phenolic compounds (13.85–33.58 mg GAE/100 g). The results showed that okra residue obtained after pectin extraction has high nutritive and functional values, and could be exploited for other economic utilization instead of discarded as waste.

The pasting properties of starch are influenced by the starch-hydrocolloid interaction in the mixed system. In this study, the effect of pectin extract from three okra genotypes (Agbagoma, Asontem, and Sengavi) at concentrations of 0%, 5%, 10%, and 15% on the pasting properties of starch were investigated. The pasting properties of the mixed systems were determined using the Rapid Visco-Analyzer. The results showed that okra pectin decreased the peak viscosity and setback value of starch with the highest exhibited by Agbagoma and Asontem. The final viscosity of starch was increased in most samples except for 10–15% Agbagoma and 15% Asontem pectin systems. The peak time (3.84 − 6.84 min) increased with increasing okra pectin concentration. Pasting temperature for the mixed systems ranged from 51.24 oC (for 10% Sengavi) to 80.65°C (for 15% Agbagoma). Overall, okra pectin affected the pasting properties of starch and decreased starch retrogradation.