Emulsification and microencapsulation properties of gum arabic

Emulsions of gum arabic solutions (10% w/w) and soya oil at oil/gum ratios of 0.25-5.0 were prepared by homogenization at 20 MPa. The resulting emulsions were subsequently spray-dried to produce powders with oil contents ranging from 20 to 82% (whv). Lipid globule size distributions and viscosities of the emulsions were determined, and particle size and percentage of extractable oil were determined for the spray-dried powders. The ability of the powders to redisperse in water was also examined. The average lipid globule Size (D-4,(3)) (0.57 mu m) did not vary significantly (P > 0.05) as the oil/gum ratio was increased from 0.26 and 1.0, but it did increase at higher ratios to a maximum of 2.02 mu m. The average particle size of the spray-dried emulsions was within the range 9-17 mu m, and the microencapsulation efficiency decreased from 100 to 48% when the oil/gum ratio was increased from 0.25 to 5.0, respectively. Powders with an oil content <50% dispersed readily in water.