Yellow, orange, red – carotenoids, curcumin and carthamin
What do carrots, bell peppers, saffron and tomatoes all have in common? They all contain natural colouring agents known as carotenoids. There are over 600 different organic pigments, fourteen of which can be found in our everyday food, mostly in fruit and vegetables. Zeaxanthin and lutein give apricots, mangoes, sweetcorn and carrots their orangey-yellow colour while higher concentrations of lycopene make strawberries, cherries, watermelon and tomatoes red5. The popular saying that eating carrots will help you see in the dark is not pure fiction; scientific research has found very high concentrations of zeaxanthin and lutein in the retina and these two pigments protect against macular degeneration and cataracts6.
The yellowness of curry is due to a different molecule, called curcumin, which can be found in turmeric. It is used to colour many foodstuffs. Safflower blooms, alsoknown as ‘bastard saffron’ or ‘dyer’s saffron’ have been used for centuries as a natural textile dye. Safflower is still popular today, used to colour Buddhist monks’ robes with a reddish-yellow tone. Safflower contains two main colouring agents, one yellow and one red (carthamin). The yellow pigment is water-soluble and can fade after successive washing. If it is treated with something alkaline, such as bicarbonate of soda, the red pigment will then emerge.
Spirulina is one of the naturally blue food colourings used in the food industry. It is phycocyanin, the blue pigment in the micro-alga, which gives it its colouring properties. Nowadays, various strains of arthrospira algae are cultivated industrially for their nutritional properties, marketed under the name of spirulina. Alongside soya, it is one of the rare sources of vegetable proteins to contain all the essential amino acids and is thus a perfect aminogram. Analyses have revealed that it also contains several vitamins and antioxidants such as beta carotene.
A natural colouring agent extracted from animal matter: cochineal carmine
Cochineals are hemipteran parasitic insects of the Dactylopiidae family and from which the natural crimson red dye carmine is derived. Young female cochineals are harvested, dried and dehydrated in their natural environment, either in the heat of the sun or in ovens. Carmine is extracted by immersing the dried cochineals in hot water. This pigment is water soluble and varies in colour according to its pH. It is very stable under variations in heat and light and resists oxidization well. The colouring agent cochineal is sometimes also called carminic acid, carmine, C175470, E120 or natural red 4. It can be found in sweets, ice creams, yoghurts and various squashes and fizzy drinks, as well as in lipsticks and toothpaste. It is used as a staining agent in histology (carmine no.4); it is in fact the most well-known colouring agent for cytologists and also the oldest, since it was already used in 1849.
In Peru, this crimson-red colouring proves highly resistant to laundering and has been identified in cloths dated at around 400 BC. The Spanish developed cochineal farming after conquering Mexico and endeavoured to maintain the highly-profitable monopoly of this colonial industry. Cochineal insects live on cacti and so, during the 18th and 19th centuries, cacti were sown on the Canary Islands and cultivated there on a large scale. Cochineal farming spread there and, during the 20th century, the Canary Islands became the first exporter of carmine. When synthetic colouring agents were discovered between 1850 and 1870, production of cochineal dye declined and, today, only remains active in Peru.
Discovery of various colouring techniques intersperse the centuries. New, ingenious and creative methods to extract pigments, mix them and then tint or dye, all add a little colour to life, simply to please our senses. Nonetheless, coloured food also brings micronutrients which are essential for good health. So don’t wait any longer! Brighten up your plate today!