ABSTRACT
The sense of taste, gustation, provides a means of avoiding potentially noxious foodstuffs or selecting for foods which have a high energy content. Five tastes are well defined—salty, sour, sweet, bitter, and umami (due to monosodium glutamate)—on the basis that no cross adaptation occurs between them. Plant alkaloids, some of which are toxic in high concentrations, are extremely bitter. A sour taste may signify a food degraded by microbiological action. By contrast a sweet food has a high content of sugars and so a readily available supply of metabolic energy. The sensory experience produced by having food in the mouth is called flavor perception, and relies on several sensory modalities. Apart from smell and taste, information about food texture is provided by mechanoreceptors and proprioceptors in the mouth and jaw innervated by trigeminal afferents. Flavor perception is important in triggering or modifying autonomic responses to feeding, for example, salivation, gastric secretion, and changes to gastrointestinal motility.
