Effect of the Reaction Volume on the Microencapsulation of Pequi (caryocar Coriaceum Wittm.) Oil by Complex Coacervation

Abstract

The oil from Pequi pulp, also known as pequi oil (PO) is a promising bioactive for the food industry, and complex coacervation is a simple encapsulation method to improve its stability and use as a food ingredient. The high reaction volume used is considered a challenge to microcapsule production by coacervation process. Therefore, the objective of this study was to evaluate the effect of the reaction volume on the formation, morphology, size, yield, and efficiency of pequi microcapsules. The complex coacervation was performed with wall material composed by polymers (gelatin and gum arabic) and pequi oil as the core material. The oil was mixed with gelatin, added the polysaccharide and pH was adjusted to 3.5, to allow the microparticle formation. The reaction volume treatments T1, T2, T3, and T4, related to wall material concentration, were 0.39, 0.77, 0.58, and 1.16 g 100 mL-1, respectively. The results of zeta potential were close to zero, without differences related to the reaction volume. Optical microscopy showed that, regardless of volume, microparticles of pequi oil presented defined walls, mononuclear core and particle size from 2.71 up to 7.27 µm, adequate for food application. In a smaller reaction volume (T1 and T3), the coacervates were aggregated due to the increase of the chemical interactions; in higher volumes (T3 and T4) the microcapsules showed an inverse behavior. The yield ranged from 58.40 up to 63.42 %. The encapsulation efficiency exhibited high values ??ranging from 90.05% ± 8.15 to 99.40% ± 0.21. The variation of reaction volume did not influence the formation of pequi oil microcapsules in the analyzed treatments, but the dispersion of the microcapsules changed. This study provided a new perspective on how the reaction volume influences the encapsulation by complex coacervation.