Food+Acidulant

Food Acidulant //By Mohamad Iswandi Bin Ishak//

Acidulants are additives that give a sharp taste to foods. They also assist in the setting of gels and to act as preservatives. The 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.

Acids, alkalis and buffers have important roles in the food industry. Acids have been used for centuries as important contributors to flavour and the acid environment they produce prevents the growth of many microorganisms. Bicarbonates, particularly bicarbonate of soda are used as mild alkalis whilst phosphates are used for their buffering action as well as for their characteristic taste. As the food industry has developed, so has the growth in production of processed foods. Many of these need the inclusion of an acidulant to give an acidic or sour taste.

Types of food accidulant that use in food products:

i) Acetic Acid
This is the acid found in vinegar and has a characteristic pungent smell. Acetic acid is widely used, particularly in the pickling industry. Naturally fermented vinegar has a variable pH and so acetic acid is added to this to form a pickling liquor with a specified acidity. It can also be used in confectionery goods and flavourings. The flavouring sodium diacetate is commonly known as 'salt 'n' vinegar' and is widely used in crisps. Acetic acid has excellent properties and hence has considerable importance as a preservative. Only acetic acid produced naturally by can legally be called vinegar. In Britain the main carbohydrate used is usually malt and so the vinegar it produces is called Malt Vinegar. Acetic acid can also be manufactured synthetically by various methods.

ii) Citric Acid

Citric acid was originally extracted from lemons and limes but it is now produced commercially by a fermentation process. The mould Aspergillus niger is used to ferment a carbohydrate source such as molasses.The function of citric acid in food are:
 * provide sharp taste in soft drinks and sweets
 * generate the optimum conditions for the formation of gels in jams, jellies, confectionary and desserts
 * help give the conditions for the stabilisation of emulsions (e.g. processed cheese and dairy products)
 * prevent the browning of salads
 * enhance the action of antioxidants and prevent deterioration in frozen food
 * act as an antioxidant in fats and oils
 * preserve meat products and help modify their texture during their processing

iii) Fumaric acid
Fumaric acid is the strongest tasting food acidulant. It has limited applications due to its very low solubility. In the main, it is used in gelatin dessert powders, cheesecake mixes and some powdered drinks. A substantial amount of fumaric acid is used in animal feedstuffs mainly because of its strong flavour and favourable price. It is manufactured synthetically from malic acid.

iv) Lactic acid
Lactic acid is widely used in the production of boiled sweets, pickled foods and as a raw material in the manufacture of important emulsifiers for the the baking industry. It is produced during anaerobic respiration and is commonly manufactured by a fermentation process, although it can be produced synthetically.

Malic acid is found naturally in apples, pears, tomatoes, bananas and cherries. It has similar applications to citric acid and is the preferred acid in low calorie drinks, cider and apple drinks. However, it has the disadvantage of being slightly more expensive than citric acid. It is produced commercially from maleic anhydride.

vi) Phosphoric acid
Is the acidulant used in the second largest amounts by the food industry. This is because of its use in one single product that is produced in massive amounts: cola drinks. Cola drinks are the best selling flavoured soft drink in the world. The acid used in these drinks is exclusively phosphoric acid. This has a harsh, biting taste which complements the cola flavour. Salts of phosphoric acid have many uses in the food industry. They can act as buffers, acidulants for baking powders and emulsifying salts in the production of processed cheese. Phosphoric acid is manufactured commercially from phosphate rock mined principally in North Africa and North America.

vii) Tartaric acid
This was the first food acidulant to be used in significant quantities although its use has now been mostly replaced by citric acid. The largest single application for tartaric acid is as a raw material for the manufacture of the emulsifiers. Tartaric acid can be manufactured by natural and synthetic routes. The natural route involves the recovery of tartaric acid from wine. The synthetic route involves the chemical reactions of maleic anhydride. An important salt of tartaric acid, potassium hydrogen tartrate (or cream of tartar), has applications as an acidulant for baking powder and sugar confectionery.