The types of colorants that may be produced using microalgae and cyanobacteria include phycobilipigments (PBPs), carotenoids and chlorophylls. These colourants may fall within the category of permitted natural colourants as per EC regulations. Advantages of microalgal colourants for food applications are nutritional value, sustainability, non-toxicity and non-carcinogenicity.
PBPs are brilliant-coloured water-soluble pigments that include:
- Allophycocyanin (bluish-green)
- Phycocyanin (blue)
- Phycoerythrin (purple)
- Phycoerythrocyanin (orange).
PBPs are proteinaceous pigments containing essential amino acid with some, such as phycocyanin, reported as possessing antioxidant, anti-inflammatory, anti-viral, anti-cancer and immuno-stimulatory activities. Carotenoids and chlorophylls are lipid-soluble light-harvesting pigments, reported with several health benefits mostly due to their antioxidative properties. Carotenoids are yellow, orange or red, while chlorophylls are green pigments. These organisms can provide an array of colours with bioactive properties and are an excellent natural source of food colour with nutritional benefits.
Food colour is the most important factor after flavour and texture to evaluate food quality because when consumers look at a food or beverage, they “taste” with their eyes. Colours are the visual palette and first impression that “sets the table” for other sensory experiences. Recently, the use of natural colourants has greatly increased as some synthetic pigments have been considered responsible for health disorders and undesirable taste. Consequently, consumers are showing more interest in alternative natural food colourants.