Properties of phycobiliproteins, such as their natural antioxidant, anti-inflammatory, food colourant, strong pigment and anti-aging activities, have given them considerable potential for use in food, cosmetics and medicinal applications.  They have also proven to be therapeutic in treating diseases such as Alzheimers disease and cancer.  Given their large range of applications and potential uses, researchers have been trying to find and develop ways to produce and purify phycobiliproteins to meet the growing demand for them. One such phycobiliprotein is C-phycocyanin (C-PC), which is found in spirulina.  A limiting factor of C-PCs usage in these applications is its protein stability, given that in its natural form, C-PC is highly sensitive to light and heat when in aqueous solution, due to its photosensitive phycocyanobilin (PCB) chromophore, which also makes it prone to free-radical oxidation. Like other natural food colourants, C-PC is also sensitive to acidic conditions and oxidant exposure. This has prompted studies to develop methods of stabilising C-PC/PCB and expand their applications to other food systems.
More details on the applications of phycocyanin in food and medicine can be found here.