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

Abstract

Encapsulation of vanillin through β-cyclodexterin inclusion complex coacervates (β-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/β-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 μm 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/β-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/β-cyclodextrin inclusion is the result of chemical interactions, but physical interaction between core and shell leads to encapsulate vanillin/β-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.