Types of food additives and their functions
A food additive is a natural or synthetic substance which is added to food to prevent spoilage or to improve its appearance, taste or texture.
Types of food additives and their functions
Food additives that are commonly used are:
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Preservatives are substances added to food to slow down or to prevent the growth of microorganisms so that food can be kept for longer periods of time.
Table shows some examples of preservatives and how they work.
|Preservative||Example||How it works|
|Salt||Salted fish||Salt or sugar draws the water out of the cells of microorganisms and retards the growth of microorganisms.|
|Vinegar||Pickled mango||Vinegar provides an acidic condition that inhibits the growth of microorganisms.|
|Sodium nitrite or sodium nitrate||Burger, sausage and luncheon meat||These preservatives slow down the growth of microorganisms.|
|Benzoic acid or sodium benzoate||Oyster sauce, tomato sauce, chilli sauce and fruit juice|
|Sulphur dioxide||Fruit juice|
Some preservatives can cause side effects on health.
- Sodium nitrite is added to meat to preserve and to stabilise its red colour. However, sodium nitrite can cause stomach cancer. During cooking, the nitrites produce nitrosamines, which are carcinogenic.
- Eating too much food preserved with salt such as salted fish increases the risk of high blood pressure, heart attack and stroke.
- Eating too much food preserved with sugar can cause obesity, tooth decay and diabetes.
- Sulphur dioxide may cause asthma and allergies in certain people who are sensitive to this additive.
- Food containing fats and oils can turn rancid, that is, the fats and oils are oxidised to become unpleasant-smelling acids, on exposure to the air.
- All foodstuff are vulnerable to oxidation. Examples are the browning of apples or potatoes exposed to air.
- Antioxidants are added to food to prevent oxidation that causes rancid fats and brown fruits.
- The use of BHA and BHT has been controversial as it has produced adverse reactions in dogs. Thus, there is a restriction on the amount of this antioxidant used.
- Vitamins C and E are among the safest antioxidants known.
- Vitamin C inhibits the formation of carcinogenic nitrosamineS, stimulates the immune system and protects against chromosome breakage.
- Vitamin E neutralises free radical compounds before they can damage cell membranes and helps to reduce the risk of heart disease and cancer.
Table shows some examples of antioxidants.
|Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT)||Margarine||To retard rancidity in oils.|
|Ascorbic acid (vitamin C)||Fruit juice||To preserve the colour of fruit juices.|
|Alpha tocopherol (vitamin E)||Vegetable oils||To retard rancidity in oils.|
|Sodium citrate||Cooked cured meat||To stop fats from turning rancid.|
- Flavourings are used to improve the taste of food and restore taste loss due to processing.
- Examples of flavouring are sugar, salt, vinegar, monosodium glutamate (MSG), aspartame and synthetic essences such as pentyl ethanoate.
- Table shows some examples of Flavourings.
|Monosodium glutamate (MSG)||Frozen food, spice mixes, canned and dry soups, salad dressings and meat or fish- based products||To bring out the flavour in many types of food.|
|Diet drinks, low- calorie frozen desserts and some soft drinks||To sweeten food.|
|Synthetic essences Pentyl||Pentyl ethanoate (banana flavour), ethyl butanoate (pineapple flavour), methyl butanoate (apple flavour) and octyl ethanoate (orange flavour)||To produce artificial flavours which resemble natural flavours.|
- Many food are actually emulsions. Emulsions are either oil droplets suspended in water or water droplets suspended in oil.
- Stabilisers are substances which help to prevent an emulsion from separating out.
- Stabilisers are used in food which contain oil and water. Examples of these foods are margarine, butter, ice cream and salad cream such as mayonnaise.
- Examples of stabilisers are lecithin, mono- and di-glycerides of fatty acids.
- Thickeners are used to thicken food.
- Acacia gum can act as a thickener as well as a stabiliser.
- Table shows some examples of thickeners.
Thickeners Example Modified starch Instant soups and puddings Pectin Jam Acacia gum Chewing gum, jelly and wine Gelatine Yogurt Xanthan gum Sauce, salad dressing
- Food colourings are dyes.
- Food processing often leads to a loss of colour.
- Food dyes are used to add or restore the colour in food in order to enhance its visual appeal and to match consumers’ expectations.
- Food dyes can be classified into natural and artificial food dyes.
- Artificial food dyes are usually used because they are more uniform, less expensive and have brighter colours than natural food dyes.
- Many food dyes are azo compounds or triphenyl compounds.
- Azo dyes have colours such as red, orange and yellow, whereas triphenyl dyes have colours such as blue and green.
- Tartrazine, a yellow azo dye, is used in orange drinks, custard powder, sweets and apricot jam. Tartrazine is believed to cause hyperactivity in children.
- Brilliant blue FCF, a blue triphenyl dye, is found in beverages, jellies, confections and syrups. It can be combined with tartrazine to produce various shades of green.
Do we need food additives?
- Many countries have enacted laws to control the use of food additives so as to safeguard the health of their citizens. In Malaysia, the public are protected against health hazards in the use of food additives by Food Act 1983 and Food Regulation 1985.
- Before an additive is used, it must be approved by the government.
- Food additives are never given permanent approval, but are continually reviewed and modified or withdrawn when necessary.
- Thus, food additives can be considered safe in our diet.
The advantages of using food additives are as follows.
- They make the food stay fresh longer, look nicer and taste better.
- They make seasonal crops and fruits available throughout the year.
The disadvantages of using food additives are as follows.
- Some of the food additives are associated with diseases like cancer, asthma, allergies and hyperactivity.
- Some food additives make the food less nutritious.