Preparation of microcapsules of W/O/W emulsions containing a polysaccharide in the outer aqueous phase by spray-drying

A water-in-oil-in-water (W/O/W) multiple emulsion containing a hydrophilic substance, 1, 3,6,8-pyrenetetrasulfonic acid tetrasodium salt (PTSA), and a wall material in its inner and outer aqueous phases, respectively, was prepared by a two-step emulsification using a rotor/stator homogenizer, and was further homogenized with a high-pressure homogenizer. Maltodextrin or gum arabic were used as wall materials, and olive oil was used as the oily phase. The high encapsulation efficiency for PTSA (>0.9) was realized. The emulsion was spray-dried to produce microcapsules of W/O/W type. The efficiencies of the microcapsules prepared with maltodextrin and gum arabic were 0.82 and 0.67, respectively. Stability of the microcapsules was examined at 37 degreesC and 12%, 33% and 75% relative humidity. Microcapsules prepared with maltodextrin were more stable than those prepared with gum arabic.