Stability of C-Phycocyanin, a Blue Dye from Spirulina Maxima

Abstract

Spirulina maxima is characterized by its high protein content, which represents up to 70% of its dry mass. Among its nutrients is C-Phycocyanin (C-PC), a phycobiliprotein responsible for the blue-green color. The FDA (Food and Drug Administration) in the United States recognized Spirulina maxima as GRAS (generally recognized as safe). To obtain the C-PC extract, S. maxima biomass was dried and suspended in 40 mL of 100 mM phosphate buffer, pH 7.8, using an orbital shaker at 150 rpm and 40°C for 25 min. To calculate the concentration of C-PC (mg mL-1), the supernatant was read at 615, 620, 652, and 280 nm. The stability of the extract was analyzed for 0, 3, 6, 18, 24, 48, and 72 h, its response to temperature (4, 20, 40, 60, and 100 °C), pH (3, 5, 7, 7.8, and 9), and exposure to light (90 µmol m-2 s-1). In C-PC, greater stability was observed at pH 4-7 and 20°C, but under light. As the pigment concentration increased, the tendency for the drink to turn blue also increased. However, in the sensory evaluation, no significant differences were observed. This study demonstrated the stability of this natural pigment as a feasible alternative for the addition of various products, indicating its commercialization potential.