Phytase-loaded core-shell microparticles for enzyme stabilization using ethanol anti-solvent precipitation

In plant-based diets, phytate reduces the adsorption of minerals. Fortifying foods with phytase can improve mineral bioavailability by hydrolyzing phytate. However, phytase is susceptible to environmental stress such as heat and acidic conditions encountered during food processing. A core-shell microparticle composed of a phytase-chitosan core and a shell consisting of cross-linked alginate-κ-carrageenan was developed using ethanol anti-solvent precipitation. The ethanol concentration, phytase-to-chitosan ratio, and alginate-κ-carrageenan concentration were evaluated to produce stable core-shell microparticles. The core-shell microparticles had a loading capacity of 32.7% with a high encapsulation efficiency of 80.3% and uniform micro-size with a diameter of 3.2 μm (CV = 9.4%, PDI = 0.178). Loaded phytase retained 62.7% enzymatic activity after heat treatment and digestion conditions. The core-shell microparticles effectively retained phytase activity under typical food processing conditions.