Enhancing phycocyanin stability through encapsulation: optimization of maltodextrin and sodium alginate ratios

Phycocyanin from Spirulina sp. exhibits significant nutritive benefits but faces major limitations in industrial applications due to instability toward abiotic stress factors such as light, temperature, and pH. Encapsulation is an effective solution to enhance phycocyanin’s stability against these stressors. The present study analyzed the double encapsulation of phycocyanin by optimizing encapsulant ratios of maltodextrin (MD) and sodium alginate (SA). The testing formulations used in the study were 6.5%, 7.5%, and 8.5% w/w of MD and 3.5%, 2.5%, and 1.5% w/w of SA, formulated in the ratio of 6.5 MD:3.5SA, 7.5 MD:2.5SA, and 8.5 MD:1.5SA and encapsulated phycocyanin in 1:1 ratio. The results showed that the 8.5 MD:1.5 SA matrix achieved the highest encapsulation efficiency (99.8 ± 0.01%), supported by structural and functional analyses, including thermal degradation and antioxidant activity studies. Thermal stability of the 8.5 MD:1.5 SA encapsulated phycocyanin was retained for 30 min at 60 °C, and antioxidant activity remained high, with 90.2 ± 0.47% at 30 min. In vitro release studies further revealed that the 8.5 MD:1.5 SA matrix effectively protected phycocyanin in acidic environments, with the potential for targeted release in the small intestine. Overall, the 8.5 MD:1.5 SA encapsulated phycocyanin demonstrates enhanced stability, making it a promising candidate as a functional food and natural colorant in the food industry.