The Basic Tastes
It is likely that we can recognize only a few basic tastes. Most neuroscientists put the number at
five. The four obvious taste qualities are:
How do we perceive the countless flavours of food?
First, each food activates a different combination of the basic tastes.
Second, most foods have a distinctive flavour as a result of their taste and smell
Third, other sensory modalities contribute to a unique food-tasting experience (e.g.
texture, temperature, and pain sensations)
The Organs of Taste
Although we taste with our tongue, there are other areas of the mouth (e.g. palate, pharynx, and
epiglottis) that are also involved. Odours from the food pass, via the pharynx, into the nasal
cavity, where they can be detected by olfactory receptors.
The tip of the tongue is most sensitive to sweetness, the back to bitterness and the sides to
saltiness and sourness. However, most of the tongue is sensitive to all basic tastes.
The surface of the tongue is scattered with small projections called papillae. Each papilla has
from one to several hundred taste buds (see Fig. 8.2) and each of these have 50 – 150 taste
receptor cells. Taste cells make about 1% of the tongue epithelium. Taste buds also have
basal cells that surround the taste cells and a set of gustatory afferent axons. A person typically
has 2000-5000 taste buds.
Tastants at very low concentrations will not be tasted, but at some critical concentration, the
stimulus will evoke a perception of taste. This is the threshold concentration. At levels just