Esterification of guar gum hydrolysate and gum Arabic with n-octenyl succinic anhydride and oleic acid and its evaluation as wall material in microencapsulation

The present study was undertaken to introduce hydrophobicity in guar gum hydrolysate (GGH) with a view to develop a suitable alternative to gum Arabic (GA) as wall material for microencapsulation. This was done by esterification with n-octenyl succinic anhydride (OSA) and oleic acid. The study was carried out by optimizing three parameters in the esterification process, viz. concentration of the acid, temperature, and time of reaction by response surface methodology (RSM). The reaction was monitored in terms of degree of substitution (DS), and optimized for maximal DS. The maximum DS of GGH oleate, GGH-OSA, and GA-OSA was found to be 0.061, 0.072, and 0.070, respectively. These derivatives were evaluated for their ability to be used as wall materials in microencapsulation with respect to emulsion stability, viscosity and particle size. Our results indicate the wall materials to follow the order GA-OSA > GGH-OSA > GA > GGH-oleate.