FIZZ AND BUZZ

The fizzy appearance of carbonated drinks needs to be backed by sharpness of flavour. It is acids that provide this quality.

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COLOURS

We need colour in food because all of the senses contribute to the experience of eating.

FLAVOURINGS

In truth there are only really four flavours: sweet, sour, bitter and salt. What we call flavour is a subtle combination of these four blended with the odours that food gives off.

How acids confer zest on food and drinks

Zest is a highly desirable attribute in food, and sharpness of flavour is always due to acids. The classic examples are cola drinks where besides the carbon dioxide which produces the actual fizz, phosphoric acid (E338) gives the sharpness. All fruits contain varying degrees of sugar but without their characteristic acids; citric in lemons, malic in apples, tartaric in grapes etc; they would be sickly and dull. The word acid does not have particularly friendly connotations, but acids of one kind or another are a major component of natural foods.

The acids that are added to food are all, except phosphoric acid, found in natural foodstuffs anyway. Besides imparting sharpness of flavour, acids are used because the overall acidity of foods can be crucial. In jam-making for example the acidity of the fruit determines its setting properties. Acids also have preservative and antioxidant properties.

The most commonly used acid is citric acid (E330). Originally derived from citrus fruits it is now produced by fermentation of molasses by an Aspergillus mould. It has many uses besides simply adding tartness: it is also an antioxidant and a preservative. Next in the league table is phosphoric acid (E338) for its use in cola drinks.