Development of vanillin/β-cyclodexterin inclusion microcapsules using flax seed gum-rice bran protein complex coacervates

Encapsulation of vanillin through beta-cyclodexterin inclusion complex coacervates (beta-CD-IC) was developed to achieve higher thermal stability and controlled release of vanillin. The effect of protein to polysaccharide (Pr: Ps) ratio and core (Vanillin/beta-CD-IC) to wall (coacervate) ratio on the vanillin encapsulation as well as thermal, microstructural and physical characteristics of microcapsules were investigated. Microcapsules had particle size ranging from 0.75 to 4.5 mu m with negative surface charge and narrow size distribution. Although particle size and encapsulation efficiency were increased by increasing the Pr:Ps ratio and core to wall ratio, the zeta-potential decreased. Vanillin/beta-cyclodexterin loaded microcapsules had the maximum encapsulation efficiency about 85% at core to wall ratio of 1:3 and Pr:Ps ratio of 9:1. Structural studies by Fourier-transform infrared spectroscopy (FTIR) indicated the entrapment of encapsulant and X-Ray diffraction data and scanning electron microscopy (SEM) images showed that microcapsules have amorphous structure with soft surface. Furthermore, FTIR results indicated the formation of vanillin/beta-cyclodextrin inclusion is the result of chemical interactions, but physical interaction between core and shell leads to encapsulate vanillin/beta-cyclodextrin inclusion in rice bran protein-flaxseed gum (RBP-FG) coacervates. Microencapsulation increased the vanillin thermostability and its shelf life. Therefore, it is possible to increase thermal stability of vanillin against environmental conditions. (C) 2019 Elsevier B.V. All rights reserved.