This hand-colored scanning electron micrograph shows oil-filled glands on a Peppermint (Mentha x piperita) leaf; image by Martin Oeggerli / Micronaut.
Mints are widely distributed aromatic herbs. Most species grow best in wet environments and moist soils, growing between 10–120 cm tall. The most popular mints for commercial usages are peppermint (Mentha × piperita), native spearmint (Mentha spicata), Scotch spearmint (Mentha x gracilis), and cornmint (Mentha arvensis).
The culinary source of mint are fresh or dried leafs. In the visually predominant peltate glandular trichomes, the secretion is stored in an enlarged subcuticular cavity, which gives these oil-filled glands their glossy bulbous appearance. Both, peltate and capitate glandular trichomes produce secretions containing monoterpenes. Peltate glandular trichomes have eight secretory cells on top of one stalk cell and one basal cell, whereas the much smaller capitate (pale bright appearance) glandular trichomes have just one secretory cell, one stalk cell and one basal cell. Non-glandular trichomes (i.e. “hairs”) appear much more elongated and contain no aromatic substances.
The substances that give the mints their characteristic aromas and flavors are menthol (the main aroma of peppermint and Japanese peppermint) and pulegone (in pennyroyal and Corsican mint). The compound primarily responsible for the aroma and flavor of spearmint is L-carvone.
Mint leaves are used in teas, beverages, jellies, syrups, candies, and ice creams. In Middle Eastern cuisine, mint is used in lamb dishes, while in British cuisine and American cuisine, mint sauce and mint jelly are used, respectively. Additionally, mint essential oil and menthol are extensively used as flavorings in breath fresheners, drinks, antiseptic mouth rinses, toothpaste, chewing gum, desserts, and candies, such as mint (candy) and mint chocolate.
Finally, mint oil is also used as an environmentally friendly insecticide for its ability to kill some common pests such as wasps, hornets, ants, and cockroaches.