Improvement of phycocyanin stability at different temperatures using microencapsulation by whey protein isolate

Abstract

Phycocyanin is a blue pigment in cyanobacteria known for its antioxidant activity and can be applied as a natural food colorant. However, one drawback to applying phycocyanin in food products is their high-temperature instability. In this research, we investigated the effect of encapsulation of phycocyanin using whey protein isolate (WPI) as the wall material to improve high-temperature stability. The study also assessed the physiochemical properties of microencapsulated phycocyanin. Phycocyanin was extracted from dry biomass Spirulina using a cold maceration method. Then, phycocyanin extract was encapsulated with prepared emulsions containing 0.25%, 0.50%, 0.75%, and 1.00% WPI as wall materials. The result showed all microencapsulated phycocyanin, regarding various concentrations of WPI, showed lower phycocyanin degradation at 60°C and 70°C at various heating times compared to control, suggesting higher stability. The control sample had 35.55±0.33% and 62.61±0.55% concentration degradation at 60°C and 70°C after 10 min heating. The microencapsulated phycocyanin with 0.50% WPI had 12.67±2.08% and 19.95±2.02% at 60°C and 70°C after 10 min heating. The encapsulation efficiency achieved 98-99% regarding various concentrations of WPI. There was no significant difference in solubility between the control and microencapsulated phycocyanin. Our result concluded that microencapsulation, using WPI as wall material, improved the high-temperature stability of phycocyanin.