Why Do Peppers Taste Hot?

Peppers are fruit of plants in the genus Capsicum, named because plants in the genus contain capsaicin. The chemical is an irritant for many mammals, including humans, and is responsible for the hot and spicy flavor characteristic of peppers.

Botany

The genus Capsicum falls within a family of flowering plants called Solanacea (nightshade), which includes paprika, belladonna, petunia, potato, tomato and eggplant. Some Solanacea family members have medicinal value while others--such as bittersweet nightshade--are poisonous to humans and some animals.

Capsaicin

Capsaicin is a primary ingredient in pepper spray. When peppers are handled or cooked, the chemical causes a burning sensation if it comes into contact with eyes, skin or other mucous membranes.

Anatomy

The hottest parts of peppers are the seeds and ribs because they contain the highest concentration of capsaicin. Generally, a pepper's heat is inversely proportional to size, with smaller peppers being hotter than larger peppers.

Scoville Hotness Scale

The Scoville Heat Scale, developed in 1912 by an American chemist named Wilbur Scoville, measures the heat of peppers in Scoville heat units. Green peppers are generally milder than red peppers. For example, a green bell pepper has a heat rating of zero while a habanero pepper--well known for being intensely spicy--has a heat rating of 100,000 to 350,000.

Medicinal Uses

Capsaicin has been used to treat pain associated with arthritis and psoriasis. Capsaicin cream, sold over the counter with brand names such as Zostrix, is believed to reduce levels of Substance P, a neurotransmitter responsible for pain sensations.

References

• Capsaicin; Memorial Sloan-Kettering Cancer Center
• The Scoville Heat Scale

Resources

• Chili Pepper Magazne