Taste (gustation): how we perceive basic tastes and flavor

Anatomy and receptors

The sensory cells responsible for taste are clustered in taste buds located mainly on the surface of the tongue but also on the soft palate, pharynx and near the epiglottis. Each taste bud contains receptor cells that respond to certain molecules. Signals from these cells are carried by cranial nerves to brainstem nuclei and then relayed to regions including the gustatory cortex, where conscious perception of taste emerges.

Basic taste qualities

• Sweet — indicates sugars and energy-rich nutrients.
• Sour — detects acids, can signal spoilage or unripe fruit.
• Bitter — often associated with potentially toxic compounds.
• Salty — senses sodium and other salts important for physiology.
• Umami — a savory taste linked to amino acids such as glutamate.

These categories are broad: many subtler sensations arise from combinations of receptor activity plus retronasal olfaction (smell from the back of the nose) and oral texture. The old notion of a rigid "tongue map" that divides taste zones is inaccurate; most areas of the tongue have mixed sensitivity.

Function, development and disorders

From an evolutionary perspective, gustation guides dietary choices and protects against ingestion of poisons. Taste sensitivity changes across the life span and can be affected by illness, medications, smoking or injury. Clinical conditions include ageusia (loss of taste), hypogeusia (reduced taste), and dysgeusia (distorted taste). Research into taste perception informs nutrition, food science and treatments for taste disorders.

Taste is tightly integrated with culture and cooking: culinary techniques manipulate sweetness, acidity, saltiness, bitterness and umami to create balanced dishes. For further general information see introductory resources on the sense of taste (overview) and more specific discussions about human gustation (human taste), animal comparisons (animal taste), tongue anatomy (tongue), the concept of flavor and food evaluation (food), oral physiology (mouth), bitterness receptors (bitter), throat receptors (epiglottis) and brain processing (gustatory cortex).