Sensory systems of the brain: the gustatory system

The gustatory system is a specialized sensory system dedicated to evaluating potential food sources, and is the main driver of feeding decisions.¹ In contrast to the olfactory system, which can distinguish millions of kinds of odours, the gustatory system can only distinguish five basic taste qualities: sweet, salty, bitter, sour, and umami (the flavour associated with the ‘savoury’ taste of amino acids).¹ While limited, this taste palate is sufficient to meet all essential dietary requirements:

• Sweet taste promotes the consumption of foods rich in energy;
• Salty taste promotes a diet with correctly balanced electrolytes;
• Bitter taste offers warning against the ingestion of toxic or otherwise noxious compounds;
• Sour taste suggests the ingested food may not be fully ripe, or may be fermented;
• Umami taste promotes sufficient intake of protein.¹

Taste is often used interchangeably with flavour.¹ However, while taste only refers to the five basic qualities recognized by the gustatory system, flavour is a result of the integration of multisensory inputs from gustatory, olfactory and somatosensory inputs.¹

Reference:
1.Kandel ER, Koester JD, Mack SH, Siegelbaum SA. Principles of Neural Science, 6th edition. McGraw-Hill Professional; 2021.