Studies on the mucilages extracted from okra fruits (<i>Hibiscus esculentus</i> L.) and baobab leaves (<i>Adansonia digitata</i> L.)

Abstract

Abstract Okra fruits and baobab leaves are just two examples of foods used to give a mucilaginous quality to West African food dishes. The mucilages were extracted from both foods and purified. Preliminary studies have been conducted to characterise the mucilages chemically, as well as study their viscous behaviour in relation to their use in West African dishes. Both mucilages are acidic polysaccharides with associated protein and minerals. Neither the quantity of protein nor minerals were significantly reduced during purification. The protein was not separated from the polysaccharide by either gel chromatography or disc electrophoresis. Hydrolysis of okra mucilage revealed that the polysaccharide was composed of galacturonic acid, galactose, rhamnose and glucose (1.3:1.0:0.1:0.1). Baobab mucilage on hydrolysis was found to contain mainly galacturonic and glucuronic acids with minor quantities of galactose, rhamnose, glucose and arabinose (11.7:11.3:1.0:0.6:0.4:0.1). The mucilages form viscous solutions at low concentrations (5–10 g/litre). They attain maximum viscosity in the neutral pH range. However, the mucilage solutions are not stable to heat and lose much of their viscosity when heated.