Optimized encapsulation of anthocyanin-rich extract from haskap berries (Lonicera caerulea L.) in calcium-alginate microparticles

BACKGROUND: The chemical instability of extracted anthocyanins (ACNs) limits their application and broader use as food colorants and health-promoting functional ingredients. Encapsulation technology can improve ACN stability and widen their potential applications. OBJECTIVE: The objective of this study was to optimize the microencapsulation of ACNs from haskap berries (Lonicera caerulea L.) in calcium-alginate particles by the extrusion/gelation method. METHODS: Response Surface Methodology (RSM) by Box-Behnken (BB) design was used for the optimization, followed by the desirability function. Three input variables were evaluated: concentrations of sodium alginate (x₁, w/w %) and calcium chloride (x₂, w/v %), and gelation time (x₃, min). The responses were encapsulation efficiency (y₁, %) and particle size (y₂, μm). RESULTS: There was a good fit for the model where encapsulation efficiency was used as a separate response (R² = 97.98%), however, the model for particle size did not give as good an agreement (R² = 63.86%). The desirability function was used to optimize the two responses simultaneously and the optimum conditions were determined as 9.0% (w/w) alginate solution, 2.0% (w/v) CaCl₂, and 10 min in the gelation solution. CONCLUSIONS: These results illustrate the application of RSM followed by a desirability function to optimize encapsulation parameters for a combined response, where several measures are considered.