Monday, July 13, 2009
Chrality & smell
D-form amino acids tend to taste sweet, whereas L-forms are usually tasteless. Spearmint leaves and caraway seeds, respectively, contain L-carvone and D-carvone - enantiomers of carvone. These smell different to most people because our olfactory receptors also contain chiral molecules that behave differently in the presence of different enantiomers. how odd - I really like spearmint, and I absolutely loathe the taste and smell of caraway seeds. This applies to chemical enantiomers, as well. Hence the stark difference between n-butanol and t-butanol. I recall seeing some chiral compounds being sold as "artificial" sweeteners. Whatever the compound was, it tasted sweet, but it was the wrong handedness to be metabolized. I wondered why that didn't take the place of aspartame (which was at the time the big new 'sweetener' in the wake of sacchrine's PR downfall).