EFFECT ON THE STRUCTURE OF MICROCAPSULES BY COMPLEX COACERVATE WHEN SUBMITTED TO SEPARATION AND DRYING PROCESSES

Microcapsules (MCs) obtained by complex coacervation (CC) are formed when the amino-protonated pair (protein) with the carboxyl group (polysaccharide) interact by van der Waals interactions (vdW). The vdW forces play an important role, conferring surface adhesion, colloidal stability and self-assembling of microparticles, however, being a weak interaction, it makes the microcapsules sensitive to pH, polysaccharide concentration, charge density, molecular weight and flexibility of the polyelectrolyte chain. The objective of this work was to produce microcapsules of green coffee oil (GCO) by complex coacervation and to evaluate the morphological effects caused by centrifugation and freeze-drying. For this, a concentration of 0.65% (m/V) of biopolymers gelatin (GE) and cashew gum (GC), ratio of 1: 3.5 GE / GC, and 25% (w/w) GCO core were used, resulting in MCs-GCO. Zeta potential (ζ), process yield (PY), loading capacity (LC) and encapsulation efficiency (EE) were performed. The complex coacervation results were zeta potential (ζ) close to zero (1.86 ± 0.44 (mV)), which indicates stable microcapsules, and encapsulated efficiently the GCO (EE of 85.57 ± 1.41%), presenting 33.49 ± 0.34% and 30.87 ± 4.69 of PY and LC, respectively. Centrifugation resulted in agglomeration of MCs-GCO, which could hinder the use in hydrophilic foods, with low viscosity and low turbidity. However, the agglomeration is dispersed with a mild mixing step, showing irregular and polynuclear MCs. After freeze-drying, the material became rigid. For its application in foods, it would be necessary to reduce the granulometry, which would result in loss of GCO. Even with different morphology after freeze-drying, MCs-GCO, when rehydrated, returned to the initial morphology. Thus, GCO was efficiently encapsulated by complex coacervation. Centrifugation resulted in agglomeration of MCs-GCO and freeze-drying modified the complex shape, however, upon being rehydrated under agitation, they returned to their original (polymorphic and multinuclear) format.