Cross-linked coacervates of cashew gum and gelatin in the encapsulation of pequi oil

ABSTRACT: Pequi oil is rich in bioactive compounds which can be encapsulated to increase protection against extrinsic environmental factors. A delayed degradation of pequi oil may occur by using microencapsulation technology, in addition to masking unpleasant flavors and aromas. Complex coacervation is a technique based on the electrostatic interaction between two oppositely charged biopolymers which form a matrix complexed around an agent of interest. However, cross-linking the particles is often necessary in order to make them more rigid. The objective of this research was to produce and characterize pequi oil microparticles in a cashew gum (CG) and gelatin (GE) matrix cross-linked with tannic acid. Cross-linked pequi oil microparticles were produced by varying the concentrations of biopolymers (0.5% to 1.5%) and tannic acid (0.3% to 8.1%) using a rotational central compound design. Ratio of cashew gum, gelatin and oil was 2:1:1 (m/m/m);respectively, at pH 4.5. The cross-linking process was performed with tannic acid for 30 minutes at 40 °C. The optimized formulation by means of the rotational central compound design for microparticle formation was 0.65% biopolymers (CG and GE) and 6.9% tannic acid. Increasing the tannic acid percentage in the cross-linking of the pequi oil particles had a higher yield and encapsulation efficiency. Cross-linking provided an increase in the degradation temperature of material; and consequently, improved the thermal stability of the particles. The cross-linking process was advantageous in producing the microparticles.