Encapsulation of rice bran oil in tapioca starch-soya protein isolate complex using spray drying

Microencapsulation of rice bran oil was done using spray drying technique for different oil concentrations (20, 25 and 30%), drying inlet air temperatures (140, 150 and 160 ºC) and a combination of wall material (tapioca starch and soya protein isolate) at different ratios (1:1, 3:1 and 5:1). The total solid content in the mixture used for spray drying was kept constant at 30%. A three-factor, three-level Box-Behnken design was employed for conducting the experiments in order to maximize encapsulation efficiency and gamma oryzanol content, and minimize peroxide value of the encapsulated powder. A polynomial regression model was fitted and the optimum conditions obtained were, 20% oil concentration, 2.6:1 starch-protein ratio (wall material) and 140ºC drying inlet air temperature. At optimum conditions, encapsulation efficiency was found to be 76.97%, total gamma oryzanol content was 12240 ppm and peroxide value was 1.49 meq/kg oil.