Retronasal smell

Retronasal smell, retronasal olfaction, or mouth smell, is the ability to perceive flavor dimensions of foods and drinks. Retronasal smell is a sensory modality that produces flavor. It is best described as a combination of traditional smell (orthonasal smell) and taste modalities. Retronasal smell creates flavor from smell molecules in foods or drinks shunting up through the nasal passages as one is chewing. When people use the term smell, they are usually referring to orthonasal smell, or the perception of smell molecules that enter directly through the nose and up the nasal passages. Retronasal smell is critical for experiencing the flavor of foods and drinks. Flavor should be contrasted with taste, which refers to five specific dimensions: (1) sweet, (2) salty, (3) bitter, (4) sour, and (5) umami. Perceiving anything beyond these five dimensions, such as distinguishing the flavor of an apple from a pear for example, requires the sense of retronasal smell.

Evolutionarily, smell has long been presumed to be a less-important sense for humans, especially compared to vision. Vision appears to dominate human stimuli perception, but researchers now argue that smell cues are highly informative to humans despite being less obviously so. Before his death in 1826, French gastronome Brillat-Savarin published his book, the title of which is translated to The Physiology of Taste; Or, Meditations on Transcendental Gastronomy: Theoretical, Historical, and Practical Work, in which he makes the first mention of the importance of smell in the “combined sense” of taste. He defines taste in terms of the five taste dimensions in addition to flavor created with the nasal apparatus.Avery Gilbert, in his book The Nose Knows, reviews the work of Henry T. Finck, an American philosopher from the late 1800s who published a groundbreaking essay titled “The Gastronomic Value of Odours.” Flink called flavor a “second way of smelling,” and much subsequent scientific investigation in the early 1900s focused on attempting to break down smell dimensions into basic categories, a feat that has proven too complicated due to the vast number and complexity of odors.

Food connoisseurs and chefs are increasingly capitalizing on the newly ascertained understanding of the role smell plays in flavor. Food scientists Nicholas Kurti and Hervé This expanded upon the physiology of flavor and its importance in the culinary arts. In 2006, This published his book, Molecular Gastronomy: Exploring the Science of Flavor, in which he explores the physical mechanisms that bring about flavor perception. Kurti and This influenced others, such as Harold McGee, who’s 1894 book, On Food and Cooking: The Science and Lore of the Kitchen, has been extensively revised in 2004 and remains a key reference on the scientific understanding of food preparation. His book has been described by television personality Alton Brown as “the Rosetta stone of the culinary world.” Such a breakthrough in the understanding of the mechanisms behind experiencing the flavor of different foods is likely to continue inspiring those in the culinary arts to create novel combinations and recipes.

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Wikipedia