There are a large variety of peppers (Capsicum annuum), that are very different from one another and can be divided into several different species and varieties. The most widely used variety of peppers in Europe and the United States are bell peppers. They have three or four chambers and can be up to 15 cm in length and 10 cm in diameter. The most popular variety turns red when it matures, but the yellow ones are also popular, as are the orange, purple, and green varieties. Cubanelle peppers are somewhat smaller peppers. The Anaheim variety (New Mexico) of peppers is somewhat larger and pointed. The poblano variety is a little wider. The short wax / hot wax variety has a waxy surface and is often yellowish or white in color (immature). Long wax is slightly less spicy. Cascabel chili peppers come in red, yellow, or brown and even though they are significantly smaller (5–6 cm) than other varieties, the skin is thick and firm and they work particularly well for stuffed peppers.
From Wikipedia: “The bell pepper (also known as sweet pepper or pepper in the United Kingdom, Canada and Ireland, and capsicum in Australia, India, Pakistan, Bangladesh, Singapore and New Zealand) is a cultivar group of the species Capsicum annuum. Cultivars of the plant produce fruits in different colors, including red, yellow, orange, green, chocolate/brown, vanilla/white, and purple. Bell peppers are sometimes grouped with less pungent pepper varieties as "sweet peppers". The ribs and seeds inside bell peppers may be consumed, but some people find the taste to be bitter.
Peppers are native to Mexico, Central America, and northern South America. Pepper seeds were imported to Spain in 1493, and from there spread to other European, African, and Asian countries. Today, China is the world's largest pepper producer, followed by Mexico and Indonesia.”
“Capsicum peppers are rich sources of antioxidants and vitamin C. The level of carotene, like lycopene, is nine times higher in red peppers. Red peppers have twice the vitamin C content of green peppers.
Red and green bell peppers are high in para-coumaric acid.”
Capsaicin in Capsicum:
“The bell pepper is the only member of the Capsicum genus that does not produce capsaicin, a lipophilic chemical that can cause a strong burning sensation when it comes in contact with mucous membranes. The lack of capsaicin in bell peppers is due to a recessive form of a gene that eliminates capsaicin and, consequently, the "hot" taste usually associated with the rest of the Capsicum genus. This recessive gene is overwritten in the Mexibelle pepper, a hybrid variety of bell pepper that produces small amounts of capsaicin (and is thus mildly pungent). Sweet pepper cultivars produce non pungent capsaicinoids, with many physiological effects similar to the more pungent sister compound capsaican.”
From “en.wikipedia.org/wiki/Capsicum”: “Capsicum fruits and peppers can be eaten raw or cooked. Those used in cooking are generally varieties of the C. annuum and C. frutescens species, though a few others are used, as well. They are suitable for stuffing with fillings such as cheese, meat, or rice. They are also frequently used both chopped and raw in salads, or cooked in stir-fries or other mixed dishes. They can be sliced into strips and fried, roasted whole or in pieces, or chopped and incorporated into salsas or other sauces, of which they are often a main ingredient. They can be preserved in the form of a jam, or by drying, pickling, or freezing. Dried peppers may be reconstituted whole, or processed into flakes or powders. Pickled or marinated peppers are frequently added to sandwiches or salads. Frozen peppers are used in stews, soups, and salsas. Extracts can be made and incorporated into hot sauces.”