Curcumin encapsulation in multilayer oil in water emulsion: Synthesis using ultrasonication and studies on stability, antioxidant and release activity.

Abstract

Curcumin is a natural polyphenol compound which is obtained from the turmeric plant, having numerous health promising benefits. In order to deliver the curcumin into the human body, it is necessary to develop an efficient carrier system for its encapsulation such that the physico-chemical properties of curcumin can be preserved during the storage. In this study, the encapsulation stability, antioxidant activity and release properties of curcumin encapsulated in the primary emulsion (PE: 0.0022 % (w/w) curcumin, 9.99 % (w/w) oil, 0.9 % (w/w) Whey protein isolate, pH 7) and secondary emulsion (SE: 0.00108 % (w/w) curcumin, 4.90 % (w/w) oil, 0.443 % (w/w) WPI, 0.2 % (w/w) sodium alginate, pH 5) prepared using ultrasonication was analyzed. It was observed that the formation of a double layer coating of secondary biopolymer over the primary coated droplet enhanced the encapsulation efficiency and antioxidant activity of the curcumin during the storage of 3 weeks. Moreover, the multilayer emulsions were freeze dried in order to see the effect of dehydration of emulsion on the stability of multilayer coated droplets. FTIR analysis indicated the presence of all the constituents including curcumin after the freeze drying of the emulsions. SEM images showed that the microstructure of emulsion droplets was found to be uniformly distributed in case of SE. The antioxidant activity of curcumin encapsulated in SE was found to be higher during storage whereas it was significantly reduced in other encapsulated systems like PE, olive oil and ethanol. In vitro release of curcumin from the multilayer emulsion was carried out under the simulated intestinal conditions of pancreatin enzyme and bile salt. The maximum release of 71% and 63% was obtained in SE and PE, respectively within 2 h of digestion. Overall this study provides useful information on the formation of multilayer emulsion as a carrier system for the better protection and controlled release of curcumin useful for the food and pharmaceutical applications.