Capsaicin in Capsicum
For more details on this topic, see Capsaicin.The fruit of most species of Capsicum contains capsaicin (methyl vanillyl nonenamide), a lipophilic chemical that can produce a strong burning sensation (pungency or spiciness) in the mouth of the unaccustomed eater. Most mammals find this unpleasant, whereas birds are unaffected. The secretion of capsaicin protects the fruit from consumption by mammals while the bright colors attract birds that will disperse the seeds.
Capsaicin is present in large quantities in the placental tissue (which holds the seeds), the internal membranes and, to a lesser extent, the other fleshy parts of the fruits of plants in the genus Capsicum. Contrary to popular belief, the seeds themselves do not produce any capsaicin, although the highest concentration of capsaicin can be found in the white pith around the seeds.
The amount of capsaicin in the fruit of Capsicums is highly variable and dependent on genetics and environment, giving almost all types of Capsicums varied amounts of perceived heat. The only Capsicum without capsaicin is the bell pepper, a cultivar of Capsicum annuum, which has a zero rating on the Scoville scale. The lack of capsaicin in bell peppers is due to a recessive gene that eliminates capsaicin and, consequently, the "hot" taste usually associated with the rest of the Capsicum family.
Chili peppers are of great importance in Native American medicine, and capsaicin is used in modern medicine—mainly in topical medications—as a circulatory stimulant and analgesic. In more recent times, an aerosol extract of capsaicin, usually known as capsicum or pepper spray, has become widely used by police forces as a non-lethal means of incapacitating a person, and in a more widely dispersed form for riot control, or by individuals for personal defence.
Although black pepper and Sichuan pepper cause similar burning sensations, they are caused by different substances—piperine and hydroxy-alpha sanshool, respectively.
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