CO-ENCAPSULATION OF IRON AND ASCORBIC ACID BY SPRAY DRING AND FLUIDIZED BED COATING OF MICROPARTICLES

Due to insufficient iron intake through diet, iron deficiency is a global issue, linked to various diseases. Food fortification with iron, especially in combination with ascorbic acid, can be used to address this deficiency. Microencapsulation of iron is an alternative to prevent oxidation. However, spray drying can lead to low encapsulation efficiency and porous particles. Therefore, strategies to improve microparticle properties are needed. This study evaluates two approaches: (i) combining protein with maltodextrin in the wall material to form a protein film on the microparticles’ surface, aiming for denser particles; and (ii) coating particles in a fluidized bed. These strategies may provide better protection, bioavailability, and controlled release. Microparticles containing ferrous sulfate and ascorbic acid were produced by spray drying, using whey protein isolate and maltodextrin as encapsulating agents in ratios of 0:100 (MP0), 30:70 (MP30), and 50:50 (MP50). The microparticles were physicochemically characterized and evaluated for encapsulation efficiency and morphology. Scanning electron microscopy showed spherical, irregular particles with concavities in al formulations. Encapsulation efficiency of ascorbic acid and Fe²⁺ ranged from 60.5% (MP0) to 91.6% (MP30) and from 13.2% (MP50) to 49.7% (MP30), respectively. MP30 microparticles exhibited better retention and protection properties of the active compounds and were selected for coating with hydroxypropyl methylcellulose (1%) in a fluidized bed, at 1.5 ml/min solution rate and 50 ºC. The coated particles (C-MP30) formed aggregates, characterized similarly to uncoated particles. Stability analysis under accelerated conditions (50 ºC, 70% relative humidity) for MP30 and C-MP30 showed that C-MP30 particles had better initial stability, ensuring higher concentration of the compounds during the first days. However, the coating did not interact positively with the particle throughout the analysis, showing greater degradation of the active compounds.