Encapsulation of hexylsalicylate in an animal-free chitosan-gum Arabic shell by complex coacervation

Fabrication of oil (hexylsalicylate) encapsulated microcapsules comprising a shell of gum Arabic and fungal chitosan via complex coacervation was investigated herein. This study highlights the influence of the fabrication conditions including the ratio of gum Arabic to chitosan, their net electrokinetic charge/zeta-potential and turbidity on the physico-mechanical properties of the resulting microcapsules. Glutaraldehyde was employed as a chemical cross-linking agent. Three states of the capsules were characterised namely, moist, air-dried and spraydried using several analytical techniques (SEM, TEM, FTIR, and UV-Vis spectrophotometry). Moreover, the microcapsules were assayed for their mechanical properties including rupture force, nominal stress at rupture, and nominal deformation at rupture, which were determined to be 2.0 +/- 0.1 mN, 3.6 +/- 0.3 MPa, and 22.7 +/- 1.5%, respectively. An encapsulation efficiency (similar to 60%) of the oil-based active ingredient and an oil leakage rate (< 10% after one month) in water environments were determined. Such promising results suggest the above mentioned vegetable chitosan-gum Arabic microcapsules to be a potential carrier for the encapsulation of fragrance ingredients, which presents a new opportunity to globally overcome cultural and religious concerns associated with animal sourced products.