Influence of system formulation on the release of encapsulated food active compounds. Analysis based on a...

Encapsulation technology is used in the food industry mainly to protect unstable active compounds and allow their controlled release at a specific site. The release is strongly influenced by the structure of the encapsulating matrix (e.g., its formulation). In this study, the influence of alginate-based particle formulation (matrix) on astaxanthin (active compound) release was experimentally evaluated and theoretically analyzed using a mechanistic mathematical model. Particles were obtained by external ionic gelation using gelling solutions with different calcium concentrations (25.75 mM, 250 mM, 474.25 mM) and equal curing time (30 min). The theoretical analysis of the active release from the encapsulation systems studied showed good agreement with the experimental data (MAPE < 15 %). The model assumes that water diffusion, active dissolution and diffusion, and matrix swelling and erosion occur simultaneously. Analysis of the dimensionless model parameters and theoretical profiles of the volume-averaged fractions of released active, absorbed water, remaining polymer, and developed matrix stress showed that for higher calcium concentrations in the gelling medium, water uptake and matrix erosion were slower, swelling had a greater effect, and the matrix exhibited more elastic behavior. The results highlight the potential of the proposed model as a valuable tool for the design and optimization of encapsulation systems.