Optimization of Wall Materials for Astaxanthin Powder Production from Shrimp Shell Extract Using Simplex Lattice Mixture Design

Shrimp shell waste is an attractive source of value-added bioactive-rich by-products. Shrimp shell extract containing astaxanthin was recovered by solvent extraction method (petroleum ether/acetone/water with a ratio of 15 : 75 : 10) and ultrasound process (amplitude 20% for 15 min at 35°C). The extract was then encapsulated by freeze-drying using wall materials such as maltodextrin (with the dextrose equivalent (DE) of 7 (MD7) and 20 (MD20)) and modified starch (Hi-Cap 100) incorporated at different ratios. Simplex lattice with augmented axial points in the mixture design was applied for the optimization of wall material. The optimal wall materials were 29.4% (MD7), 34.0% (Hi-Cap 100), and 36.6% (MD20), with encapsulation yield (Y) of 94.6%, encapsulation efficiency (EE) of 91.8%, astaxanthin content (Ast) of 46.1 μg/g DW, and DPPH scavenging capacity of 64.0%, respectively. The optimized microcapsules had spongy morphology and brittle and flaky mass. The degradation kinetics of bioactive astaxanthin in UV light was evaluated and found to follow first-order reaction kinetics. The microcapsules obtained under optimal wall composition exhibited the highest UV light stability with half-life values of 76.8 h, demonstrating a high stability.