Physicochemical characterisation of the hydrocolloid from Brea tree (Cercidium praecox)

Abstract

SummaryThe Brea gum (BG) is a hydrocolloid obtained as phloematic exudate from Cercidium praecox. The exudate was purified by solution and subsequent drying. BG showed high solubility in water 28.3% at 25 °C that increased as temperature was raised. Viscosity of BG solutions increased with BG concentration increase and temperature decrease. Addition of acid or alkali produced changes in solution viscosity as the electrostatic charges on the macromolecule were altered. Solution density at 25 °C increased linearly with hydrocolloid concentration up to saturation. BG lowered the surface tension of water to 51.3 mN m−1 when BG concentration was 5%, remaining constant for higher concentrations. The diameter of oil droplets emulsified decreased and foamability increased with BG concentration increase up to 5% of BG. BG presents adequate functional characteristics for use as stabiliser in preparations with high content of insoluble solids and as stabiliser and emulsifier in emulsions and foams.