What Aristotle didn't know about flavor.

Aristotle confused taste with flavor because he did not realize that chewing food releases odorants (volatiles) that rise up behind the palate and enter the nose from the rear (retronasal olfaction). When Aristotle bit into an apple, the flavor of the apple was perceptually localized to his mouth so he called it "taste." The correct attribution of flavor to the sense of olfaction was not made until 1812, and the term retronasal olfaction did not come into common use until 1984. Recent research has focused on interactions; tastes can change the perceived intensities of retronasal olfactory sensations and vice versa. In particular, some retronasal olfactory stimuli enhance sweet taste signals in the brain. In addition to sweetening foods (and reducing dependence on sugars and artificial sweeteners), retronasal olfaction can bypass damaged taste nerves and thus perhaps restore sweetness perception in patients. Public Significance Statement This study reviews the history (Aristotle to present) of retronasal olfaction, which is perception of food-borne odorants (volatiles) from the mouth. It is now known that the signal for sweet taste in the brain can be enhanced by retronasal perception of certain volatiles; recent work has identified many more of these volatiles than were previously known. Sweetening foods and beverages with these volatiles may contribute to reductions in the use of sugar and artificial sweeteners and may also restore sweet taste to patients with taste nerve damage.