Hydrolyzed Karaya Gum: Gelatin Complex Coacervates for Microencapsulation of Soybean Oil and Curcumin

Abstract

This is the first report on utilizing hydrolyzed karaya gum (HKG) as a novel polyanion material for complex coacervation with gelatin A. With negative zeta potentials at pH > 2.5, HKG formed the complex coacervate with a maximum yield at pH 3.75 and 1: 1 HKG:gelatin ratio. The optimal complex coacervates were used to encapsulate soybean oil containing curcumin using different shell:core ratios, homogenization speeds, concentrations of emulsifier, and drying techniques. Optical microscopy showed that increasing homogenization speed and Tween 80 concentration produced smaller and more uniform coacervate particles. Increasing the shell:core mass ratio from 1 to 4 resulted in a linear increase in encapsulation efficiencies for both soybean oil and curcumin. Accelerated peroxidation tests on the microcapsules showed enhanced protective effects against oil peroxidation when increasing shell:core ratios and using freeze-drying instead of oven-drying at 50 oC. In vitro release of curcumin in simulated gastric and intestinal fluids was faster when using freeze-drying and decreasing shell:core ratio. This study shows perspective novel applications of HKG in microencapsulating active ingredients for food and pharmaceutical industries.