Sweetness

For other uses, see Sweetness (disambiguation).
"Sweet" and "Sweetening" redirect here. For other uses, see Sweet (disambiguation) and Sweetening (disambiguation).
Sweet foods, such as this strawberry shortcake, are often eaten for dessert.

Sweetness is a basic taste most commonly perceived when eating foods rich in sugars. Sweet tastes are generally regarded as pleasurable. In addition to sugars like sucrose, many other chemical compounds are sweet, including aldehydes, ketones, and sugar alcohols. Some are sweet at very low concentrations, allowing their use as non-caloric sugar substitutes. Such non-sugar sweeteners include saccharin, aspartame, sucralose and stevia. Other compounds, such as miraculin, may alter perception of sweetness itself.

The perceived intensity of sugars and high-potency sweeteners, such as aspartame and neohesperidin dihydrochalcone, are heritable, with gene effect accounting for approximately 30% of the variation.[1]

The chemosensory basis for detecting sweetness, which varies between both individuals and species, has only begun to be understood since the late 20th century. One theoretical model of sweetness is the multipoint attachment theory, which involves multiple binding sites between a sweetness receptor and a sweet substance.

Studies indicate that responsiveness to sugars and sweetness has very ancient evolutionary beginnings, being manifest as chemotaxis even in motile bacteria such as E. coli.[2] Newborn human infants also demonstrate preferences for high sugar concentrations and prefer solutions that are sweeter than lactose, the sugar found in breast milk.[3][4] Sweetness appears to have the highest taste recognition threshold, being detectable at around 1 part in 200 of sucrose in solution. By comparison, bitterness appears to have the lowest detection threshold, at about 1 part in 2 million for quinine in solution.[5] In the natural settings that human primate ancestors evolved in, sweetness intensity should indicate energy density, while bitterness tends to indicate toxicity.[6][7][8] The high sweetness detection threshold and low bitterness detection threshold would have predisposed our primate ancestors to seek out sweet-tasting (and energy-dense) foods and avoid bitter-tasting foods. Even amongst leaf-eating primates, there is a tendency to prefer immature leaves, which tend to be higher in protein and lower in fibre and poisons than mature leaves.[9] The "sweet tooth" thus has an ancient heritage, and while food processing has changed consumption patterns,[10][11] human physiology remains largely unchanged.[12] Biologically, a variant in fibroblast growth factor 21 increases craving for sweet foods.

  1. ^ Hwang LD, Zhu G, Breslin PA, Reed DR, Martin NG, Wright MJ (2015). "A common genetic influence on human intensity ratings of sugars and high-potency sweeteners". Twin Res Hum Genet. 18 (4): 361–7. doi:10.1017/thg.2015.42. PMID 26181574.
  2. ^ Blass, E.M. Opioids, sweets and a mechanism for positive affect: Broad motivational implications. (Dobbing 1987, pp. 115–124)
  3. ^ Desor, J.A.; Maller, O.; Turner, R.E. (1973). "Taste acceptance of sugars by human infants". Journal of Comparative and Physiological Psychology. 84 (3): 496–501. doi:10.1037/h0034906. PMID 4745817.
  4. ^ Schiffman, Susan S. (2 June 1983). "Taste and smell in disease (Second of two parts)". The New England Journal of Medicine. 308 (22): 1337–43. doi:10.1056/NEJM198306023082207. PMID 6341845.
  5. ^ McAleer, N. (1985). The Body Almanac: Mind-boggling facts about today's human body and high-tech medicine. New York: Doubleday.
  6. ^ Altman, S. (1989). "The monkey and the fig: A Socratic dialogue on evolutionary themes". American Scientist. 77: 256–263.
  7. ^ Johns, T. (1990). With Bitter Herbs They Shall Eat It: Chemical ecology and the origins of human diet and medicine. Tucson: University of Arizona Press.
  8. ^ Logue, A.W. (1986). The Psychology of Eating and Drinking. New York: W.H. Freeman.
  9. ^ Jones, S.; Martin, R.; Pilbeam, D. (1994). The Cambridge Encyclopedia of Human Evolution. Cambridge: Cambridge University Press.
  10. ^ Fischler, C. (1980). "Food habits, social change and the nature/culture dilemma". Social Science Information. 19 (6): 937–953. doi:10.1177/053901848001900603. S2CID 143766021.
  11. ^ Fischler, C. Attitudes towards sugar and sweetness in historical and social perspective. (Dobbing 1987, pp. 83–98)
  12. ^ Milton, K. (1993). "Diet and primate evolution". Scientific American. 269 (2): 70–77. Bibcode:1993SciAm.269b..86M. doi:10.1038/scientificamerican0893-86. PMID 8351513.