Composition and physicochemical properties of locust bean gum extracted from whole seeds by acid or water dehulling pre-treatment

The purpose of this study was to extract locust bean gum (LBG) from whole seeds by two different dehulling pre-treatments. The first process consisted in separating the endosperm (gum) from the hull and the germ after seeds’ pre-treatment with boiling water. The second one used acidic pre-treatment. Then the composition and the physicochemical characteristics of the isolated gum were studied in order to evaluate the effect of extraction process. Comparisons to commercial samples and temperature influence on solubility and rheological properties are included. The yield and quality of Locust bean gum from whole seeds depended on the separation method used. The separation of the seed components by boiling water pre-treatment furnished a higher yield of yellowish endosperm (51–61% w/w), whereas acid dehulling pre-treatment gave an off-white gum yield (37–48% w/w). However, the mannose and galactose content, the solubility, the molecular size and the dynamic viscosity, were higher for LBG from acid dehulling pre-treatment. In addition, a considerable influence of solubilization temperature on macromolecular characteristics and on viscosity properties was noticed.