Ascorbic acid microencapsulation by spray chilling: Production and characterization

- The carrier consisted of mixtures of lauric acid and oleic acid.
- High effective encapsulation efficiencies were achieved (58%-88%).
- The oleic acid content highly influenced the properties of the microparticles.
- Ascorbic acid release from the microparticles followed the Ritger-Peppas kinetic model.
- Intermediate concentration of oleic acid in the carrier leads to low core release.

This study reports on the use of spray chilling to synthesize solid lipid microparticles containing ascorbic acid and describes the characterization of the resulting microparticles. Lauric acid (LA)/oleic acid (OA) mixtures at 70/30, 80/20, and 90/10 g:g ratios served as carrier. Different carrier/core (core = aqueous ascorbic acid solution 30 g/100 g) ratios, namely 70/30, 75/25, and 80/20 (g:g), were tested. The synthesized microparticles presented high TE values, which varied from 89% to 98%; differences between experiments were not significant (p > 0.05). EE values were inversely proportional to the amount of LA in the carrier; EE ranged from 58% to 88%. The mean volume moment of particle D[4,3] of the microparticles containing LA concentrations of 70 g/100 g of lipid and 90 g/100 g of lipid ranged from 45 to 67 μm and from 18 to 24 μm, respectively. The core release profile revealed that microparticles containing intermediate concentration of LA in the carrier (80 g/100 g of lipid) retained the ascorbic acid core better. The ratio between the fatty acids used as carrier rather than the ratio between the carrier and the core affected the characteristics of the microparticles the most.