Structure and physicochemical properties of Ghanaian grewia gum

F.M. Kpodo, Jakob K. Agbenorhevi, Jekaterina Alba, Alan Smith, Gordon Morris, Vasileios Kontogiorgos

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Grewia polysaccharides were isolated using sodium metabisulphite and phosphate buffers and the influence of the different extraction techniques on the chemical composition and structural characteristics of the extracts were determined. Structure and chemical composition of the resulting polysaccharide extracts were determined using FT-IR and NMR spectroscopy, neutral sugar analysis, size exclusion chromatography coupled to multi-angle light scattering (SEC-MALS), dilute solution viscometry and steady shear rheology. Chemical composition was similar irrespectively of the extraction solvent used and ranged between 11.1 and 16.5% for protein, 53.4 and 66.9% for total carbohydrate, 18.5 and 35.1% for total uronic acid and 23.5 and 28.6% for rhamnose. Predominate sugars in the extracts were rhamnose and uronic acids with spectroscopy showing the presence of esterified groups. Intrinsic viscosity varied between 6.5 and 9.1 dL g−1 and related with molar mass (754–2778 × 103 g mol−1). Grewia polysaccharide dispersions at 1 g dL−1 exhibited a shear thinning flow behaviour with crude and sodium metabisulphite extracts having higher viscosities. Overall, differences in extraction techniques produced grewia samples with tailored bulk properties for use in the food and pharmaceutical industries.
Original languageEnglish
Pages (from-to)866-872
Number of pages7
JournalInternational Journal of Biological Macromolecules
Early online date2 Nov 2018
Publication statusPublished - 1 Feb 2019


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