Microencapsulation of curcumin by complex coacervation of lactoferrin and carboxymethyl tara gum for incorporation into edible films

Abstract

Curcumin is a natural bioactive agent found in turmeric (Curcuma longa) with many health benefits, but with susceptibility to alkaline conditions, light, oxidation and heat. The present research aimed microencapsulate curcumin by complex coacervation using lactoferrin (LF) and carboxymethyl tara gum (CMTG) for application in edible films. The study of wall material formation was carried out by phase diagram, zeta potential and isothermal titration calorimetry. Curcumin was encapsulated by complex coacervation using different core-to-wall ratios and total biopolymer concentration. Finally, the microcapsules were used for the fabrication of edible gelatin-based films. The results showed that LF and CMTG could form complexes at pH 4.5 by electrostatic attraction with high affinity and optimum encapsulation efficiency of curcumin (74.78 %). The microcapsules protected curcumin during the oral and gastric phases with an average release in the intestinal phase of 81.81 %. After in vitro gastrointestinal digestion, the bioaccessibility of encapsulated curcumin was approximately 67 %. Curcumin microcapsules were added to edible gelatin films, which resulted in reduced light transmission and presence of antioxidant activity (FRAP and DPPH·⁺). The films containing microcapsules had their mechanical properties preserved. Therefore, curcumin-containing microcapsules formed by complex coacervation of LF/CMTG can be used in the production of edible films with high functional properties.