During the aroma micro-encapsulation process, a significant phase is to choose a suitable carrier material that provides protection for the substance being encapsulated and to determine the optimal process parameters. The properties of spray dried emulsion as well as the emulsion properties-dependent attributes of powders obtained impact the efficiency of the micro encapsulation process. Therefore, the objective of this study was to determine the correlation between the per cent content of individual carriers in the emulsion of vanillin aroma and some selected physical properties of microcapsules obtained, and the efficiency of micro-encapsulation. A mixture of maltodextrin DE = 10 and gum arabic was used as a carrier for the vanillin aroma micro-encapsulation. The solutions prepared for the experiment had levels of concentration of 20 and 30 % (m/m) of the above named substances. The flavour addition was 21.7 % (m/m) in proportion to the total dry matter content in the solution. The content of gum arabic in the solutions was 11 %; additionally, the solutions of 30 % concentration level were made with a reduced content of gum arabic of 7 %. The solutions were homogenized using a two-stage homogenization at pressure values of 20 : 7.5 MPa. The emulsion was dried in a spray dryer with a rotational speed of the disc being 650 RPS and a feed rate of raw material being 1·10-6 m3·s-1, at an inlet air temperature of 160 °C. The reduction from 30 to 20 % of dry matter content in the emulsions resulted in the decrease in their viscosity (from 11 to 4 mPa·s) and density (from 1103 to 1060 kg/m3). The reduction of the per cent content of gum arabic caused the viscosity to decrease from 11 to 8 mPa·s; however, there were no statistically significant changes in the density of emulsions. Changing the concentration of the carriers from 20 to 30 % caused a statistically significant decrease in the apparent and loose bulk density, porosity of the powder bed, and in the shape factor of the particles as well as an increase in the content of water and diameter of particles. As for the powders produced from solutions having 30 % of the added carriers with a lower content of gum arabic (7 %) and compared to the powders with a higher amount of gum arabic, a statistically significant decrease in the particle diameters was found as was an increase in the loose bed density and bed porosity. The efficiency of micro-encapsulation was between 55 and 75 %. A positive correlation was confirmed to exist between the encapsulation efficiency and apparent density, and the average particle diameter of powders.
vanillin aroma, density, equivalent diameter, micro-encapsulation efficiency