Mistakenly known as Blue spirulina, Phycocyanin is a pigment-protein complex from the light-harvesting phycobiliprotein family, found abundantly in Spirulina and other Cyanobacteria, or blue-green algae as they are referred to.
All phycobiliproteins are water-soluble, so they cannot exist within the membrane like carotenoids do. Instead, phycobiliproteins aggregate to form clusters that adhere to the membrane called phycobilisomes.
Phycocyanin is characterised by its light blue color, absorbing orange and red light, particularly near 620 nm, and emits fluorescence at about 650 nm (both depending on which type it is). Allophycocyanin absorbs and emits at longer wavelengths than phycocyanin C or phycocyanin R.
Phycocyanin Stability and Heat Resistance
C-phycocyanin is found in cyanobacteria which thrive around hot springs, as it can remain stable up to around 70°C, with identical light absorbing behaviors at 20 and 70°C.
Thermophiles contain slightly different amino acid sequences, making them stable under these higher conditions. Molecular weight is around 30,000 Da. Stability of this protein in vitro at these temperatures has been shown to be substantially lower. Photo-spectral analysis of the protein after 1 min exposure to 65°C in a purified state demonstrated a 50% loss of tertiary structure.
Natural Food Colorant
As a product, phycocyanin is extracted from spirulina, and is used in the food and beverage industry as a natural coloring agent. Indeed, Blue Spirulina offers a nutritious alternative to its chemical counterparts, which have recently been banned for use by the FDA due to their carcinogenic potential.
This new trend suggests a new paradigm shift, where food colorants are not only harmless, but can even be beneficial for our health. The addition of a therapeutic substance as a food colorant presents a brighter future for all those with a sweet tooth, and a massive market potential for spirulina growers who take the innovative approach.
Medical Uses of Phycocyanin
Phycobiliproteins have fluorescent properties that are used in immunoassay kits, to test antibodies and identify infections within the body. Such tests can be used to identify carcinogenic cells in the body, providing a healthy alternative to the common radiation treatment.
Phycocyanin can promote blood cell regeneration, improve lymphocyte activity and lymphatic system to improve immune function, and comprehensively enhance the disease resistance of the body. In addition, C-phycocyanin could inhibit TGF-β1-induced EMT and C-PC might be a potential anti-fibrosis drug