Red hot chilli peppers!!!

The chilli pepper or chilli is the fruit of plants from the genus Capsicum.  The substances that give chili peppers their intensity when ingested or applied topically are capsaicin (8-methyl-N-vanillyl-6-nonenamide) and several related chemicals, collectively called capsaicinoids.

Cayenne pepper

Chili peppers originated in the Americas but spread around the world and India is now the world's largest producer, consumer and exporter of chili peppers.

When consumed, capsaicinoids bind with pain receptors in the mouth and throat that are responsible for sensing heat. Once activated by the capsaicinoids, these receptors send a message to the brain that the person has consumed something hot. The brain responds to the burning sensation by raising the heart rate, increasing perspiration and release of endorphins.

The "heat" of chili peppers was historically measured in Scoville heat units (SHU), which is a measure of the dilution of an amount of chili extract added to sugar syrup before its heat becomes undetectable to a panel of tasters; the more it has to be diluted to be undetectable, the more powerful the variety and therefore the higher the rating.  The modern commonplace method for quantitative analysis of SHU rating uses high-performance liquid chromatography to directly measure the capsaicinoid content of a chili pepper variety. Pure capsaicin is a hydrophobic, colorless, odorless, and crystalline-to-waxy solid at room temperature, and measures 16,000,000 SHU.



Chemistry of a Chilli-click to enlarge



Capsaicin extracted from chillis is also used in pepper spray as an irritant, a form of less-lethal weapon.

Red chilies contain large amounts of vitamin C and small amounts of carotene (provitamin A). Yellow and especially green chilies (which are essentially unripe fruit) contain a considerably lower amount of both substances. In addition, peppers are a good source of most B vitamins, and vitamin B₆ in particular. They are very high in potassium, magnesium, and iron. Their very high vitamin C content can also substantially increase the uptake of non-heme iron from other ingredients in a meal, such as beans and grains.

For more information visit:-
http://www.compoundchem.com/2014/01/15/why-chilli-peppers-are-spicy-the-chemistry-of-a-chilli/
http://en.wikipedia.org/wiki/Chilli_pepper