Measuring the Preferences of Taste Neurons NERVE CELL ACTIVITY TESTS demonstrate that taste neurons can respond to different types of taste stimuli--be they sweet, salty, sour or bitter--although the cells usually respond most strongly to one type. (Bitter stimuli not shown.) Image:
Bite into a gooey candy bar, and what mouth sensations do you experience? Mmmm ... chewy, sweet, creamy--with the signature, slightly bitter richness of chocolate as you close your mouth to swallow and the aroma wafts up into your nasal passages. Indeed, smell is an important component of flavor, as anyone with a severe head cold can testify.
Flavor is a complex mixture of sensory input composed of taste (gustation), smell (olfaction) and the tactile sensation of food as it is being munched, a characteristic that food scientists often term "mouthfeel." Although people may use the word "taste" to mean "flavor," in the strict sense it is applicable only to the sensations arising from specialized taste cells in the mouth. Scientists generally describe human taste perception in terms of four qualities: saltiness, sourness, sweetness and bitterness. Some have suggested, however, that other categories exist as well--most notably umami, the sensation elicited by glutamate, one of the 20 amino acids that make up the proteins in meat, fish and legumes. Glutamate also serves as a flavor enhancer in the form of the additive monosodium glutamate (MSG).
This article was originally published with the title Making Sense of Taste.