Chemicals in food

Many chemical substances such as flavourings, sweeteners, dyes, antioxidants, fortifiers, emulsifiers and antifoaming agents are added to food for their preservation and enhancing their appeal. With the exception of preservatives, fortifying agents, antioxidants and artificial sweeteners. The other classes of chemicals are added either for ease in processing or for cosmetic purposes. In real sense, these substance have no nutritive value.

Preservatives
Usually food is most appetizing when it comes from the production line in the food processing plant. But, during storage and distribution undesirable changes occur in flavour, colour, texture and appetitic appeal. To delay these changes many chemical substances are added to food. These chemicals are called food preservatives. They prevent spoilage of food due to microbial growth. commonly used preservative is sodium benzoate (C6H5COONa).In order to preserve colourless food materials potassium metabisulphite or sodium metabisulphite is used.

Artificial sweetening agents
These are another types of food additives which are non-nutritive substituents for sugar. The first popular artificial sweetener was saccharin. It was marketed as its water-soluble sodium or calcium salt. Saccharin is approximately 300 times sweeter than cane sugar.
Besides saccharin, the other commonly marketed artificial sweeteners are aspartame, alitame, sucralose etc. Aspartame is unstable at cooking temperatures, limiting its use as a sugar substitute to cold foods and soft drinks. Alitame is more stable than aspartame during cooking. One potential problem with alitame and similar type of high-potency sweeteners is the difficulty in controlling sweetness of food.

Antioxidants
These are the important food additives. Antioxidants are compounds which retard the action of oxygen on the food. It helps on the preservation of the food materials. These are more reactive towards oxygen than the food products. They also reduce the rate of involvement of free radicals in the ageing process of food. The two commonly used antioxidants are butylated hydroxy toluene (BHT) and butylated hydroxy anisole (BHA). Vitamin E is a natural antioxydent.

Edible colour
Edible colours used for food are essentially dyes. These are used to colour food products. Some of the azodyes using as food dyes are suspected to be dangerous for asthma patients and young children. However, natural dyes like carotene are safe food dyes.