Microencapsulation of Ferrous Sulfate in Lipid Matrices Produced by Spray Chilling: Characterization, Controlled Release, and In Vitro Gastric Behavior

Iron deficiency is a global nutritional concern, and food fortification is a strategy to address it. However, direct iron fortification can negatively impact sensory attributes. Spray chilling microencapsulation offers a solution while enhancing iron bioavailability. This study aimed to produce iron-containing microparticles using spray chilling with varying ratios of beeswax and cocoa butter. The ratios had minimal impact on overall yield (73%–75%). The microparticles exhibited β and β′ polymorphic forms, and the inclusion of cocoa butter led to a more amorphous and heterogeneous matrix, resulting in more complex thermal behavior. Higher cocoa butter content improved iron retention (79%–81%) compared with higher beeswax concentrations (69%–70%). LPMs with greater cocoa butter content exhibited reduced iron release, with release kinetics following diffusion and relaxation mechanisms. Iron release across different temperatures ranged from 0.11 to 0.42 mg L⁻¹, influenced by the lipid matrix, particle distribution, and size. The highest release was attributed to smaller, more homogeneous particles containing only one lipid in the matrix. LMPs effectively protected iron release under simulated gastric conditions, allowing significant release in simulated intestinal conditions (36.1%–56.3%). These iron microparticles show potential for use in the food industry, particularly for fortifying various food products, including infant formulas and supplements.