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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.

This 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.

Pectin extractable from okra (Abelmoschus esculentus L.) is known to have various food and non-food applications. The objective of this work was to investigate the effect of particle size of milled samples on okra pectin yield using two different extraction solvents. Phosphate buffer (PB) and citric acid solution (CAS) (at pH 6, temperature of 80°C and for 1 h) were used to extract pectin from 10 g of milled okra sample with varying particle sizes (0.5, 1 and 2 mm). Ethanol was added to the aqueous extract to precipitate the pectin. The crude pectin obtained was then freeze-dried and the % pectin yield was calculated. The average okra pectin yield when PB was used for extraction were 19.6±4.0%, 15.8±1.0% and 11.9±1.5% for 0.5 mm, 1 mm and 2 mm particle sizes, whereas that of the CAS counterparts were 32.7±8.1%, 25.6±0.8% and 35.6±5.5%, respectively. However, considering purity of the pectin extracts (PB > CAS), the present findings indicated that a higher pectin yield is achievable with 0.5 mm as the optimal particle size of okra pod powder using phosphate buffer as extraction solvent.

Cucurbita pepo L., Citrullus lanatus T. and Cucumis melo L. belong to the family Cucurbitaceae and are cultivated for their seeds. The fruit pulp and peel are discarded as agro-waste after seed removal. This study evaluated the physicochemical and functional properties of the pulp and pectin extracts from the Cucurbitaceae species. Proximate, antioxidant, total polyphenol and flavonoid contents were determined. The purity, structural and sugar constituents of the extracted pectin were analysed using spectrophotometric techniques (NMR, FTIR and LCMS). Results showed that the pulp wastes had high carbohydrate content (28.4 to 69.7%) and demonstrated high antioxidant activities (40 to 50%, 63 to 85% and 0.2 to 0.4 mg mL−1 for DPPH, ABTS and FRAP respectively). Cucurbita pepo L. had the highest pectin yield (13.9%), and the purity of the pectin extracts ranged from 60.4 to 75.2% for total carbohydrate and 3.3 to 4.4 % for protein. The pectin extracts showed structural similarities. LCMS fingerprints of the pectin extracts showed that the monosaccharides comprised of mannose, rhamnose, galacturonic acid, glucose, galactose, xylose, arabinose and fucose. The polymers demonstrated high water absorption capacities (309 g/100 g to 604 g/100 g) and can be applied as thickeners in food systems.

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.

Borassus aethiopum (African palmyra palm (APP)) fruit is an underutilized tropical fruit but has potential food applications. In the present work, the suitability of APP fruit–wheat composite flour in the development of noodles was investigated. The fresh APP fruit pulp was separated, oven-dried at 60°C and milled into flour. The obtained flour was mixed with commercial wheat flour to obtain three composite flours with 5%, 10% and 15% of APP fruit flour. The functional properties and proximate composition of the composite flours were determined. The cooking properties and consumer preference of the noodles developed were also evaluated. The cooking yield, water uptake and gruel solid loss ranged from 259.81% to 300.97%, 159.81% to 200.97% and 11.52% to 17.11%, respectively. The water absorption capacities, swelling power and the solubility indices of the flours ranged from 197.10% to 492.66%, 621.99% to 734.91% and 4.53 to 26.48%, respectively. On the 7-point hedonic scale, the flavour, smell, colour and overall acceptability ranged between 4.2 and 5.3, 4.8 and 5.65, 4.05 and 5.3 and 4.10 and 5.03, respectively. The inclusion of APP fruit flour at 5% level yielded noodles with enhanced nutritional quality and highest overall consumer acceptability.

Okra (Abelmoschus esculentus) is an economically important crop in sub-Saharan Africa. The vegetable is of major technological interest in food and medicinal applications. A survey was conducted by administering structured questionnaires (1560) in major okra-producing regions in Ghana to determine the level of okra utilization and nutritional and medicinal attributes of the crop. The okra pectin yield and intrinsic viscosity at different maturity stages were also investigated. Isolation of okra pectin from the pods at different harvest maturity was performed by aqueous extraction at pH 6.0. The intrinsic viscosity [η] of the okra pectin solutions was determined at 20°C using Ubbelohde capillary viscometer. The survey showed that okra is well known (96.9%) across the country among the various ethnic groups. The majority (94.7%) of the respondents use okra as food, whereas few utilized the crop as medicine (22.1%) and for other applications (9.6%). The respondents widely used okra in the form of soup (73.1%) and stew (68.7%) consumed popularly with banku (81.3%) and tuo zaafi (38.8%). The majority of respondents (65.2%) showed interest in the development of new products from okra. Highest pectin yield was obtained for intermediate matured fruits, followed by that of immature fruits and lowest for overgrown fruits. The intrinsic viscosity value, however, was highest for immature fruits. The study showed that okra is mainly used as food among various ethnic groups and that it is important to identify the most appropriate stage of development to harvest the okra fruit. This knowledge would enhance the potential of okra for specific use or functionality.

The objective of this study was to investigate the effect of okra pectin as a stabilizer and a texturizer on the quality and consumer acceptability of tigernut milk and fried yam, respectively. Okra pectin concentrations 0% (control), 0.2%, 0.4% and 0.6% were used in the preparation of tigernut milk as well as to pretreat yam slices before deep frying. The viscosity and microbial quality of the tigernut milk samples were evaluated, whilst the moisture content, oil uptake and colour of fried yam were also determined. Consumer acceptability test was conducted on both the tigernut milk and fried yam using 50 semi-trained panelists. The viscosity of the tigernut milk samples which ranged from 4.67 cP to 10.50 cP increased with increasing concentrations of okra pectin. The microbial load of all tigernut milk samples were within the acceptable limits. With the exception of sample appearance, okra pectin also had no significant effect (p > 0.05) on the sensory quality of tigernut milk. On the other hand, okra pectin treatment in the fried yam samples resulted in significantly different moisture (54.33–56.71%), oil uptake/fat content (4.00–5.50%) and colour (L*a*b*) values. Results showed that okra pectin had no significant effect (p > 0.05) on all sensory quality parameters of fried yam samples though 0.2% okra pectin treated yam had the highest mean overall acceptability. The findings suggest that treatment with okra pectin can be exploited to make appreciable impact on the quality and consumer acceptability of fried yam.