05 March 2013

Types of food additives

These drinks were used in a taste-test. Volunteers had to say which one they preferred.

All three drinks taste the same!
We 'taste' with our eyes. If food does not look appealing then we often think it tastes bad as well.
Often, when foods are cooked or processed for sale, they lose their natural colour and look less tasty. Colourings are often added to help make the food look appealing and so 'taste' better.

Three orange drinks


Emulsions in food are mixtures of oil and water. These normally do not mix and will separate if left without an emulsifier. Roll over the photograph of the mayonnaise to see the effects when the emulsifier is not added.

Mayonnaise contains oil and water. The emulsifier keeps these mixed and without it the oil and water separate.

The acceptability of any food product greatly depends on the impression of taste when it is eaten. Our sense of taste is really a combination of two of our senses, taste and smell . Both of these sense respond to certain chemicals.

Gelling agents
The functions of these substances is fairly self explanatory:
  • Gelling agents gel foods, i.e. they give shape and structure
  • Thickeners or thickening agents make foods thicker
  • Stabilisers help to maintain the physical and textural properties of foodstuffs through their production, transport, storage and cooking

Drinks, like this chocomilk, contain cocoa powder that can form a sediment when the drink is on the supermarket shelf. Stabilisers help to prevent this.

Most preservatives today are actually fungistatic in their action. That means they prevent the growth of fungi, moulds and yeasts. They have little effect on bacteria but using a combination of preservatives, with antibacterial properties, can give good all round protection. Food preservatives help to control the spread of bacteria which can cause life threatening illnesses such as salmonellosis or botulism.

Bread will quickly go mouldy under the attack of microbes


Sugar is a most important flavouring substance. It gives the sensation of sweetness and provides a source of energy. However, excessive sugar intake is linked with a number of health problems including tooth decay, obesity and diabetes.
photo of sweetener and sugar
Intense sweeteners are many times sweeter than sugar. A small amount of intense sweetener replaces a large amount of sugar

Anti-caking agents

Processed foods often contain ingredients that are mixed as powders. Anti-caking agents are added to allow them to flow and mix evenly during the food production process. They rarely have nutritional value and only a small proportion of the additives find their way into the food.
Some anti-caking agents may be found in foods. For example, magnesium carbonate is used in table salt to improve its flow during manufacture. It is left in the salt so that it flows well when being sprinkled onto food.
Examples of foods that contain anti-caking agents include:
  • vending machine powders (coffee, cocoa, soup)
  • milk and cream powders
  • grated cheese
  • icing sugar
  • baking powder
  • cake mixes
  • instant soup powders
  • drinking chocolate
  • table salt
photo of salt pot
Magnesium carbonate is added to salt to make it flow easily
Oxidation reactions happen when chemicals in the food are exposed to oxygen in the air. In natural conditions, animal and plant tissues contain their own antioxidants but in foods, these natural systems break down and oxidation is bound to follow.
Oxidation of food is a destructive process, causing loss of nutritional value and changes in chemical composition. Oxidation of fats and oils leads to rancidity and, in fruits such as apples, it can result in the formation of compounds which discolour the fruit.
Roll over the picture to see the effects of oxidation on cut apple.
Antioxidants are added to food to slow the rate of oxidation and, if used properly, they can extend the shelf life of the food in which they have been used.
Acidulants are additives that give a sharp taste to foods. They also assist in the setting of gels and to act as preservatives.
Photo of fruitsThe pH of a food is a measure of its acidity, alkalinity or neutrality. Living tissues contain solutions called buffers which help to keep a constant pH inside cells.
Many natural foods are acidic. For example, oranges, lemons, apples, tomatoes, cheese and yoghurt contain natural acids, such as citric acid, that give them their characteristically sharp taste.
Many fruits contain natural acids that give them a sharp taste

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