Effects of carrageenan and chitosan as coating materials on the thermal degradation of microencapsulated phycocyanin from spirulina sp.

Abstract

Phycocyanin is a natural substance that can be used as an antioxidant and food colorant. The quality of phycocyanin deteriorates when it is exposed to heat, and such deterioration is evidenced by decreases in its antioxidant activity and color. Encapsulation, which introduces a coating material over a substance of interest, has been applied to prevent changes in substance quality. The objective of the present research is to evaluate the kinetics of thermal degradation of phycocyanin coated with carrageenan or chitosan. Encapsulated phycocyanin samples were exposed to temperatures of 40, 50, or 60°C for 90min, and kinetics of the resulting degradation was evaluated to determine changes in sample quality. The results showed that the thermal degradation of encapsulated phycocyanin at 40-60°C follows first-order reaction kinetics with reaction rate constants (k) of 4.67-9.17 × 10-5s-1 and 3.83-7.67 × 10-5s-1 for carrageenan and chitosan, respectively, and that the k of encapsulated phycocyanin is slower than that obtained from samples without the coating materials (control). Encapsulation efficiencies (EE) of 68.66% and 76.45%, as well as loading capacities of 45.28% and 49.16%, were, respectively, obtained for carrageenan and chitosan.