So while yesterday I talked about aniseed, which is part of the carrot family (along with fennel, cumin and caraway), today is all about the different species of plant in the mint family that we use as herbs. Their characteristic flavours and aromas are down to different combinations of volatile compounds, produced by the plants as a defence from herbivores.
The flavour of sweet basil is dominated by flowery notes, as well as eugenol, which smells of cloves. Lavendar, with its characteristic perfume, contains linalool (also found in black pepper), cineole (found in eucalyptus) and linalyl acetate.
Marjoram and oregano, stalwarts of Mediterranean cooking, are very closely related – marjoram is in fact a species of oregano, though less pungent in flavour as it contains less of the aggressive compound carvacrol. Another important chemical for the flavour of oregano is thymol, also found in thyme, which is why these two herbs can taste similar.
Rosemary contains pinene, cineole and other terpenes. Sage has a warm note from camphor and thujone, both with antimicrobial action. These are also nerve toxins, so can be damaging if eaten in too large an amount (it’s recommended that pregnant women avoid eating sage).
And finally, the mints themselves. Spearmint’s flavour comes from L-carvone and pyridines, while peppermint, a hybrid of spearmint and watermint, contains menthol. Menthol binds to temperature receptors in the mouth and cause them to send signals that the mouth is up to 7 degrees C colder than it really is.
The Science Sponge 