Spirulina platensis is a microalga containing protein and other nutrients, also pigments which has several advantages in food and pharmaceuticals. Phycocyanin is a blue pigment from Spirulina sp. composed by α and β polypeptide with phycocyanobilin. Phycocyanin can be extracted by ultra-sonication method. However, this pigment can be easily degraded because of its instability caused by pH, temperature, and light. One of methods for maintaining the stability is encapsulation by coating material. Water soluble chitosan (WSC) is known as a low-molecular weight and low toxic coating material dissolve in water. The purposes of this study were to determine phycocyanin extraction with different time and evaluate the stability of phycocyanin in WSC nanoparticles. Phycocyanin-WSC nanoparticles were prepared with three different ratio of WSC to phycocyanin i.e 1:1, 1:0.75, 1:0.5 (w/w). Extraction phycocyanin using ultrasonicator for 15 min showed the highest concentration (1.28 mg/mL) and yield (2.56%). The smallest size and narrow polydispersities of phycocyanin-WSC nanoparticles was achieved with ratio of WSC to phycocyanin of 1:0.75 (w/w). Encapsulation of phycocyanin in WSC nanoparticle enhanced the stability at 50°C for 90 min. Encapsulation can be used for any supplement application.

Phycocyanin is a phycobiliprotein compound obtained from Spirulina platensis that can be used as a natural color, functional food, or as a cosmeceutical ingredient. The ultrasonication-assisted extraction (UAE) method can be an alternative to obtain phycocyanin from S. plantesis wet biomass. We were aimed to determine the effect of ultrasonication time on profile crude extract phycocyanin from wet biomass S. platensis, and to compare the profile crude extract phycocyanin produced from UEA and freeze-thawing methods. Phycocyanin was extracted from wet biomass S. plantesis using the UEA method with different times: 1) the extraction was carried out for 20, 30, 40, 50, and 60 minutes of ultrasonication, and 2) the extraction was carried out for 10, 15, and 20 minutes of ultrasonication. The result showed that UAE for 10 minutes has the highest concentration, yield, and purity index of phycocyanin, namely 1065.54±182.76 g/mL, 10.65±1.82%, 1.12±0.04. This result also was higher than the crude extract of phycocyanin obtained from the freeze-thawing method. Thus, the ultrasonic-assisted extraction (UAE) method can effectively produce phycocyanin from Spirulina plantesis wet biomass.