Mechanical characterization of fish oil microcapsules by a micromanipulation technique

This paper aims to study the mechanical properties of fish oil microcapsules made of different food-grade formulations and processing conditions, which is crucial to maintaining their mechanical integrity in further compaction for developing the final dosage form of tablet. The combination of gelatin and gum Arabic or maltodextrin were use as wall materials. Spray drying, complex coacervation, and double encapsulation (coacervation followed by spray coating) were used to prepare different fish oil microcapsules. Both fundamental physical properties and mechanical properties of microcapsules were investigated. The mechanical characterization results were obtained using a micromanipulation technique and revealed that the mean rupture forces of individual microcapsules ranged from 0.44 ± 0.11 to 1.73 ± 0.27 mN and tended to increase with increasing particle size. The Young's modulus of microcapsules was determined by fitting the experimental force versus displacement data with the Hertz model. The microcapsules prepared by coacervation of gelatin and gum Arabic followed by spray coating with a mixture of gelation and maltodextrin were the strongest and stiffest based on the calculated nominal rupture stress and Young's modulus respectively. These findings can provide guidance on choosing the most desirable formulation and processing conditions to produce strong microcapsules with desirable barrier properties for industrial applications.