Extraction of Okra plant gum and evaliation of its physico-chemical properties

Gums are polysaccharides that are capable of producing products with high viscosity at low concentrations. In this study, the okra plant gum was extracted with two solvents, water and sodium hydroxide. Extraction efficiency, viscosity, FTIR spectroum and chemical parameters were evaluated to select the optimum extraction. Okra gum extracted with sodium hydroxide compared with okra gum extracted with water, according to the hydrogen bonds between its molecules, had higher viscosity and showed upper stress against flow behavior. This extracted gum had a pseudoplastic or shear thinning behavior with shear rate of 44s-1 and the viscosity value of 11.1mPa.s. The FTIR pattern showed the dominance of oxygen-hydrogen bonds in the compound that represents a lot of parts of galactronic acid in the structure of this gum. Besides, extracting by alkali increased galactronic acid in gum and consequently increased the amount of Hydrogen-Oxygen bonds and the viscosity of the gum. The extracted gum with sodium hydroxide contained alkaline pH (9.75), >10% humidity and high dry matter (90%). Water absorption capacity was 7.9 g water/g material and total ash, protein and carbohydrates were 17.39, 22.80 and 50.464 percent, respectively. Extraction efficiency of gum depending okra pods was 2.39% for water extractingand 5.62% for sodium hydroxide extracting methods.