Development, characterization, and consumer acceptance evaluation of thermally stable capsule beads containing mixed extracts of green tea and turmeric

The aim of this study was to investigate the ability of shell (coating) formulations comprised of alginate and glucono delta lactone (GDL) to encapsulate a mixture of green tea and turmeric extracts. Three concentrations of alginate and GDL were used at 0.5%, 0.75%, and 1%, w/v and their solid ratio was varied using a factorial design. A response surface model was applied to optimize the retention of catechin and curcuminoid contents, to determine encapsulation efficiency, and to minimize undesirable flavor and taste. Increasing the concentration of alginate and GDL significantly increased the retention of catechin and curcuminoid contents, encapsulation efficiency, and consumer acceptance (p < 0.05). The encapsulating solution containing 1% of each alginate and GDL performed the best against each criterion. The thermal treatment carried out at the boiling point of water for 15 min had a significant impact on the retention of catechin and curcuminoid content which, in the thermally-treated beads, was 5.15 and 3.85 times higher than unencapsulated, respectively. The consumer acceptance of the encapsulated beads after thermal treatment was higher than that of the unencapsulated formulations as they exhibited lesser pungent flavor and bitterness. The innovative process of thermally stable microencapsulation can produce anti-cancer activity compounds involved in functional food industrial sectors.