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.

How do we taste?

Taste is a complex mixture of flavours and aroma, or smell.

The receptors for the human sense of taste are located on the tongue and on the soft palate. There are just five stimuli to which these receptors respond. These are:

  • sweet (as in sugar)
  • sour (as in acidic substances like lemon juice)
  • bitter (strong coffee or quinine in tonic water)
  • salt (table salt)
  • umami (monosodium glutamate, savouries, soya sauce, crisps)

The traditional view is that tastes are detected on different parts of the tongue (see the taste map opposite). Receptors for each taste are located in taste buds in specific areas of the tongue and each area can only detect one particular taste.

However, more recent research suggests that this may not be the case. The taste buds are still found in the same areas on the tongue but each one can detect all five tastes (sweet, sour, bitter, salt and umami). The brain is able to recognise which receptors are being stimulated and this goes towards the flavour sensation that we experience. The way in which we taste foods and perceive flavours is clearly very complex.

Our sense of smell also makes up a big part of how well we 'taste' food. Flavour molecules in the food enter the air in the nose and are detected by millions of receptors that feed information to the brain. Chewing helps to transfer more odour from the mouth to the back of the nose. The area which is sensitive to smell is located at the back of the nose where several million receptor cells per square centimetre respond to thousands of chemicals in the food.

Taste areas of the tongue

Location of the taste receptors as shown on a traditional 'taste map'.

Receptors for umami are thought to be spread evenly across the surface of the tongue.

Sight plays an unexpectedly important role in our perception of flavours. The taste of a colourless, shapeless food is extremely difficult to recognise. We may need visual "clues" to enable us to identify taste and flavour accurately.

The brain interprets signals from taste, smell and even vision before turning them into an impression of the food's taste. Different people will find different tastes nice or unpleasant. Flavourings are added to food products to give, enhance or intensify flavour.

Find out about flavourings in food