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Chemistry of Food Colourings

There is undoubtedly a link between food, its colour and its associated flavour. Would crème soda taste the same if it were not green? Would tomato sauce taste like tomatoes if it were yellow? Whether it is because a food was historically one colour or because it is associated with a specific fruit or vegetable – like anything banana flavoured is yellow or green is mint, consumers prefer that the colour of food matches its flavour.

According to Chemistry for Life, the link between colour and taste is logical. Since oranges are orange, we expect orange-coloured drinks to be orange-flavoured. Red drinks should taste like cherries, and purple drinks should taste like grapes. If a food is multicoloured, it could be mouldy and should not be eaten.

The reason, however, that food colourants are so important is that much of the food we eat is processed. These foods are altered from their natural states to make them safe, to remove harmful bacteria, or to make them appealing and to prolong their shelf life. That said, much of what we eat would not look appealing if it was not coloured, for example, hot dogs would be an unappetising grey/brown.

Food colourants can either be natural or synthetic.

Natural Food Colouring

Natural dyes have been used for centuries to colour food. Some of the most common ones are carotenoids, chlorophyll, anthocyanin, and turmeric.

Carotenoids have a deep red, yellow, or orange colour. Probably the most common carotenoid is beta-carotene, which is responsible for the bright orange colour of sweet potatoes and pumpkins. Beta-carotene is soluble in fat, which makes it a great choice for colouring dairy products. It is therefore often added to margarine and cheese.

Chlorophyll is another natural pigment, found in all green plants. Mint- or lime-flavoured foods, such as sweets and ice cream, are sometimes coloured using chlorophyll.

Anthocyanin is the best natural source for deep purple and blue colours. Grapes, blueberries, and cranberries owe their rich colour to this organic compound. It is soluble in water, and is therefore used to colour water-based products including soft drinks, and jelly.

Turmeric is another natural food additive and is often added to mustard to impart a deep yellow colour.

Artificial Colours

One of the main reasons that the food industry still uses artificial dyes is cost. Synthetic dyes can be mass-produced at a fraction of the cost of gathering and processing the materials used to make natural colourings.

Another reason is shelf life. Artificial dyes might be longer-lasting than natural ones of the same colour. Also, although nature produces an impressive hue of colours, those suitable for use as a food dye are limited. But there is no limit to the variety of colours that can be artificially produced in a lab.

Some of the most common synthetic dyes include:

· Carmosine

· Chocolate Brown HT

· Ponceau 4R

· Sunset Yellow

· Tartrazine

The future of food colourants

While it one may think natural dyes are healthier than artificial ones, this is not always the case and despite the bad publicity some artificial food dyes and colourants have received over the years, they have been proven safe to use.

The bottom line is that eating involves more than just taste. It is a full sensory experience. Both food scientists and chefs will tell you that the smell, sound, feel, and, yes, the sight of your food are just as important as taste to fully appreciate what you eat.

Chemgrit Food sources and supplies various food dyes and colourants for use in the food and beverage industry. For information contact Chemgrit Food.

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