Protein – Polysaccharide Matrix as Novel Wall Material for Rice Bran Oil Encapsulation

Abstract

An attempt was made to optimize the encapsulation of rice bran oil using tapioca starchwhey protein isolate matrix as wall material by spray drying technique. The selected independent variables for optimization were oil concentration (20, 25, 30 %), wall material starch-protein ratio (1:1, 3:1, 5:1) and drying inlet air temperature (140, 150, 160 ºC). Encapsulated rice bran oil powder was evaluated for encapsulation efficiency, peroxide value, and gamma oryzanol content. Optimization of the process conditions was carried by model fitting technique of response surface methodology using Design Expert Software. The results indicated that 20 % oil concentration, 2.2:1 starch-protein ratio, and 140°C drying inlet air temperature are optimum to obtain maximum of 79.52 % encapsulation efficiency, 12,390 ppm gamma oryzanol content, and minimum of 1.52 meq. kg-1 of peroxide value. Analysis of encapsulated powder for size and shape indicated that 90 % of the particles were below 21 μm size having spherical shape with smooth surface.