Colourings

Colourings are often added to enhance or alter foods, either to intensify their natural colour (such as gravy browning) or to give them a completely different hue (for example, adding saffron to paella).

Many dishes at home may be coloured using natural products; for example, spinach juice or chopped herbs may be used to create green sauces and mayonnaise, tomato paste to make delicate pink sauces to accompany shellfish, turmeric to give dark meat dishes a warm mahogany hue and onion skins to make golden broths. Natural colouring can also be provided when berries, grapes, or the juices of the fruits are added to foods or when sugar is heated to produce a caramel colour for desserts and sauces.

There are also a range of food colourants that may be bought in small bottles and used achieve bright colours in cakes, icing and other recipes. They should be used sparingly, a drop at a time until you have achieved the colour you want. There are around 50 dyes, pigments or other substances that have been approved for use in the European Union, all of which are given an 'E' number, ranging from E100-E199.

• E100-109 - yellows
• E110-119 - oranges
• E120-129 - reds
• E130-139 - blues and violets
• E140-149 - greens
• E150-159 - browns and blacks
• E160-199 - others

Some are entirely of natural origin, whilst others are synthetically made. Natural colourings include E100, a rich yellowy-orange extract made from curcumin, the turmeric plant. E101 is equally wholesome, also known as riboflavin or vitamin B2, and used as a yellow colourant in sauces, soups and jams. E140 is made from chlorophyll, whilst E162 is made from beetroot. E160-E161 encompass a range of carotenoids found in fruit and vegetables, such as carotene, lycopene and annatto.

However, there are a number of natural food colours that may cause allergic reactions for example, E120 (cochineal), a deep red colour made from crushed cactus beetles (Dactylopius coccus). These reactions can range from mild cases of asthma to anaphylactic shock. It has also been recommended that cochineal is eliminated from the diet of hyperactive children.

Concern about synthetic food colourings has recently been centred on 'azo dyes', a group of synthetic colours made from a by-product of coal distillation. E102, tartrazine, synthetic lemon yellow, is probably the best known of these. Azo dyes may cause allergy-type reactions in sensitive people, particularly amongst asthmatics and those with an aspirin intolerance. Reactions can include migraine, blurred vision, itching, rhinitis and gastric upset. Tartrazine is also thought to increase hyperactivity in children. Other azo dyes include E110 (sunset yellow), E122 (azorubine), E124 (ponceau 4R), E155 (brown HT).