Food additives are used to preserve the flavour or to improve the taste and appearance of certain foods. They have actually been used for many years e.g. pickling food in vinegar, adding salt to bacon, or sulfur dioxide to wine. However, the 20th century saw a huge rise in the types of additives used for preserving processed foods.
So that consumers could keep a track of the additives that were in food they were numbered with an 'E number', a European method of additive numbering. Alkanet is additive number 103. However, as it is not approved for use in Europe it does not have an E number. A similar thing is seen with acetic acid (E260). This is approved for use in Europe but not in other countries and is thus referred to as '260' in these places.
Additives can be broadly catagorised:-
Acids: these are added to food to give a sharper taste. A good example of this is vinegar.
Anticaking agents: these are added to foods such as milk or custard powders to stop them from sticking.
Antioxidants: these can be beneficial to health but stopping the effects of oxygen on some food. Vitamin C is an example of an antioxidant.
Food colouring: replaces colour that is lost in food during preparation. Also used to enhance the physical appearance of some foods.
Sweeteners: these are used to replace sugar in food and to keep the calorie content low. They can be beneficial for people with diabetes as well as preventing tooth decay and diarrohea that can be the product of too much sugar.
A lot of controversy has existed around food additives for many years, though most are considered safe. However, there are some that are known to be carcinogenic and toxic and have been linked to some adverse reaction in children such as hyperactivity.