Why red chilli and green chilli are spicy in taste?

Answer 1

Red and green chillies contain a group of chemicals called 'capsaicinoids' which cause the burning sensation. These compounds are concentrated around the centre area of the chilli, where the seeds are (though not actually in the seeds). The hottest of these is called 'capsaicin', which is an irritant to mammals and produces a burning sensation with any tissue it comes into contact with (though is only noticeable in mucous membranes such as the mouth, eyes and genitals in the case of most chillies).

Capsaicin tricks the brain into thinking the area of the body in contact with the capsaicin is being burned, causing it to produce endorphins, the body's natural pain relievers. This results in a pleasurable sensation, which is why so many people across the world are chilli lovers!

Chilli pepper heat is measure in Scoville Heat Units (SHU), after the pharmacologist Wilbur Scoville who created the rating scale. Originally this was a subjective test which required panels of volunteers to taste chilli extract diluted in water - the more water required to dilute the chilli extract so no heat was detectable, the hotter the chilli, and therefore the higher the scoville rating. The measure is now done in labs using HPLC systems, which gives a more accurate and less subjective rating of a chilli. Currently the hottest chilli in the world is the Bhut Jolokia from Assam in India, which has a rating of 1,001,304 SHU (pure capsaicin is 16 million SHU).