Preparation of spray-dried curcumin microcapsules using a blend of whey protein with maltodextrin and gum arabica and its in-vitro digestibility evaluation

Abstract

In the present study, attempts were made to prepare spray-dried curcumin microcapsules using a blend of whey proteins and carbohydrates. Curcumin was first dissolved in buffalo milk butteroil and then it was converted into an emulsion using skim milk, WPC-80, and a blend of maltodextrin and gum arabica as the wall material solids. Optimization of ingredients level for stable curcumin emulsion was done by varying core: wall material solids ratio and protein: carbohydrates ratio in the wall material solids. Particle size, zeta potential, viscosity, encapsulation efficiency, and emulsion stability of the emulsions were evaluated. Emulsion having core: wall material solids ratio of 1:2 and protein: carbohydrates ratio of 1:2 was found to yield stable emulsion with highest curcumin content and hence was selected for spray drying. Spray drying was performed at different inlet air temperatures. Bulk densities, encapsulation efficiency, moisture content, water activity, and reconstitution parameters decreased while DPPH free radical scavenging activity increased with an increase in the inlet air drying temperature. Inlet air temperature of 180 °C was found suitable for drying curcumin emulsion. In-vitro digestion of spray-dried curcumin microcapsules revealed that the developed encapsulate was resistant to gastric digestion but was digested by intestinal fluids.