Evaluation of chitosan as a wall material for microencapsulation of squalene by spray drying: Characterization and oxidative stability studies

Abstract

The present study was aimed at investigating the efficacy of chitosan as a wall material for microencapsulation of squalene by spray drying for functional food applications. Based on different core to wall material ratio (1:1, 0.5:1 and 0.3:1 on w/w basis), emulsions were prepared and evaluated in terms of emulsion stability, particle size, zeta potential, polydispersity Index (PDI), rheology and microstructure. The optimized emulsion combination was spray dried and characterized, physically and chemically. The encapsulation efficiency of the powder was found to be 26±0.6% whereas other properties such as particle size, zeta potential, water activity, hygroscopicity, Carr Index, Hausner ratio have shown satisfactory results. SEM analysis showed that the squalene microcapsules were smooth spherical particles free from dents and fissures. FTIR data further confirmed the encapsulation of squalene with chitosan. However, TGA, oxidative stability and accelerated Rancimat results showed that chitosan was not able to protect squalene from oxidation during storage. The results suggest that chitosan is not an appropriate wall material for microencapsulation of squalene and hence a combination of wall materials could be attempted for the encapsulation of squalene.

Keywords: Chitosan; Dynamic light scattering; Microencapsulation; Peroxidation; Rheology; Squalene.