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

Abstract

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 (0.5%, 0.75%, and 1%, w/v) of alginate and GDL were used, 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, encapsulation efficiency, and 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 boiling point of water for 15 min had a significant impact on retention of catechin and curcuminoid content which in 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 unencapsulated formulations as they exhibited lesser pungent flavor and bitterness. Thus, the optimized encapsulating formulations can be used to produce thermally stable microcapsules containing polyphenol-rich mixed plant extracts and used as functional ingredients.