The encapsulation of phytosterols (non-water soluble and hydrophobic solids) by spray drying using a combination of maltodextrin, arabic gum and low concentrations of surfactant (T20 with HLB 16 or SDS with HLB 40) was successfully achieved.
A significant effect of the type and concentration of surfactant on the process yield, encapsulation efficiency, phytosterols retention and product quality was found. All the observed trends were well correlated with studied feed properties (feed suspensions viscosity, particle size of the dispersed phase and wettability of wall solutions on the phytosterols). Although higher process yields were obtained by including T20, the addition of SDS led to better and satisfactory encapsulation efficiency and phytosterols retention, smaller microparticles sizes and adequate process yield for laboratory-scale spray dryers. The enhancement in performance given by SDS (with respect to T20) was explained in terms of the greater affinity between phytosterols and wall solutions. For all feed formulations, the microparticles Sauter mean satisfies the more restricted upper size limit of 25 μm, which is required to ensure the incorporation of phytosterols into the intestine micellar phase.