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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.

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.