Materials that change the orientation of polarized light are called optically active materials. Some optically active solutions rotate the direction of polarization clockwise, to the right; others rotate it counterclockwise, to the left.

All organically produced glucose rotates the direction of polarization of light clockwise. This sugar is called d-glucose. Another sugar, called l-glucose, rotates the direction of polarization to the left. It can only be made by inorganic chemical synthesis. Both d-glucose and l-glucose have the same chemical formula: C6H12O6. However, the atoms in each of these isomers are arranged in a different pattern. The left-handed sugar (l-glucose) tastes just as sweet as the right-handed one (d-glucose), but your body can't use it as an energy source. That's how left-handed sugars can produce sweetness without calories.

All of the proteins in your body and in all organisms on earth are made from amino acids that rotate the direction of polarization of light to the left. On the other hand, laboratory-synthesized amino acids, and amino acids found on meteorites, are made up of equal numbers of amino acids that rotate light to the right and amino acids that rotate light to the left. No one knows why this is so.

Los edulcorantes funcionan con ese principio, usar una molecula dextrogira en vez de levogira:

Alguien me comentó que el químico que se usa para los ambientadores de pino típicos era la misma que la que se usa en los ambientadores de limón, pero que una era la levógira y otra la dextrógira... Nunca supe si era verdad pero me hizo mucha gracia

Yo tenia entendido que el limoneno tenia dos verisiones con diferente quiralidad. Una daba olor a limon y la otra naranja.

Pensaba que no, pero el acido citrico tambien huele a limon aunque se consigue industrialmente por medio de hongos.
Si diluyes y lo pulverizas el citrico huele a estornudo.

Limonene is common in cosmetic products. As the main odor constituent of citrus (plant family Rutaceae), D-limonene is used in food manufacturing and some medicines, e.g. as a flavoring to mask the bitter taste of alkaloids, and as a fragrant in perfumery; it is also used as botanical insecticide,[6] particularly the (R)-(+)-enantiomer is most active as an insecticide. It is added to cleaning products such as hand cleansers to give a lemon-orange fragrance (see orange oil). In contrast, L-limonene has a piney, turpentine-like odor.