The effect of adding oleic acid in the production of stearic acid lipid microparticles with a hydrophilic core by a spray-cooling process

Abstract

The objective of the present work was to study the effect of adding oleic acid (OA) to the stearic acid (SA) used in the production of lipid microparticles (LP) by the spray-cooling process, the core material being a glucose solution, using lecithin as the surfactant. The fatty acid composition of the lipid raw materials was characterized. For the lipid mixtures the thermal behavior was determined by differential scanning calorimetry (DSC), and the solid fat content (SFC) and iso-solids diagrams also determined. The efficiency of encapsulation was determined in the LP produced, and also the particle size distribution, morphology and the release of the core material into the aqueous medium. The LP showed spherical, wrinkled forms. The addition of OA modified their crystallization pattern and aided in incorporation of the core material, resulting in a lower surface glucose amount of 2 to 7% for the mixtures as compared to 22% for pure SA. The encapsulation efficiency was high for the OA/SA mixtures (92%–96%) but only reached 75% when SA was used alone. The release profile was also modified, being greater for SA as compared to the mixtures containing OA.