Peppers (Revised)

Capsicum peppers (mainly Capsicum annuum, Bell pepper and capsicum frutescens, Chilli pepper) are the most popular and most widely used condiment all over the world. The genus Capsicum consists of all the ‘chilli pepper plants’ with 3-5 wild species and over 2000 cultivars. Its fruits are consumed in fresh, dried or processed form as table vegetable or spice. Capsicum peppers are extensively pickled in salt and vinegar. Colour and flavour extracts are used in both the food and feed industries, for example, ginger beer, hot sauces and poultry feed, as well as for some pharmaceutical products. Sweet, non-pungent capsicum peppers are widely used in the immature, green-mature or mature-mixed-colours stage as a vegetable, especially in the temperate zones. Capsicum extracts show promise against some crop pests.

Pepper (Capsicum annuum), belongs to the family Solanaceae and the Capsicum genus. There are approximately 30 species within the genus Capsicum, which includes a wide variety of pepper plants. C. annum includes both mild (sweet peppers e.g. Bell pepper) and spicy peppers (chilies). Other notable cultivated species within the genus include: C. frutescens (e.g. Tabasco peppers & bird's eye chili, C. chinense (extremely hot peppers. Eg. ghabanero and Scotch bonnet), C. pubescens, and C. baccatum (e.g aji amarillo and aji rocoto). Of these species, Capsicum annum is the most economically significant crop due to its spicy aroma and flavor.
Capsicum annuum is native to South America specifically in regions of Mexico, Central America, and South America. Today, it is cultivated and grown worldwide in both tropical and temperate regions, including North and South America, Asia, Africa, and Europe. In Africa, hot pepper is considered a traditional vegetable or spice, while sweet pepper is considered exotic in temperate regions.
Sweet pepper thrives in temperate climates and is essential in Western industrialized nations. Conversely, hot pepper usually prefers warmer conditions. While some hot pepper types, like aromatic hot pepper, can adapt to temperate climates, bird pepper grows too slowly for outdoor cultivation in such conditions.
Capsicum peppers are versatile crop used as condiments in various cuisines globally. Its fruits are consumed in fresh, dried or processed form as table vegetable or spice. Sweet peppers are widely used in the immature, green-mature or mature-mixed-colors stage as a vegetable, especially in the temperate zones. In contrast, chili peppers are primarily used to spice up dishes and create hot sauces and salsas. Chilies are available in a range of different forms, such as frozen, canned, dried (either in whole or crushed form), and pickled. They can also undergo various processes to create fermented goods, powders, sauces, curry pastes, and salsas. Dried chilies are frequently turned into powders for cooking purposes, and both fresh and dried chilies are utilized in the production of hot sauce. Furthermore, Capsicum leaves can be consumed and are incorporated into soups and stews.
C. annuum is a rich source of vitamins, especially vitamin C, which is essential for the immune system. It contains dietary fiber, antioxidants, and other vitamins and minerals. The compound capsaicin found in hot chili peppers may have potential health benefits, including pain relief, improved metabolism, and appetite control. Top global producers of Capsicum annuum include China, India, Mexico, Indonesia, and Turkey. In Africa, countries like Nigeria, Egypt, and South Africa are significant producers of C. annuum.
(Grubben et al., 2004, Swamy, 2023)

Species account 

Capsiccum annum (Bell/ Sweet peppers)
Sweet peppers plants are perennial, short bushes with woody branching stems growing to a height of upto 1m. Leaves: broad, dark green, and lance-shaped, with serrated edges. Flowers: white or purple bell-shaped flowers which are 2.5 cm (1 in) in diameter. Fruits: thick and fleshy fruit walls, which are typically bell-shaped, though they can also be elongated or blocky in shape. come in a range of vibrant colors, including red, green, yellow, and orange.
Sweet peppers have a mild taste due to their low capsaicin content, making them suitable for salads, stuffing, and various culinary applications where a mild, non-spicy taste is desired. The crops are perennial but are normally grown as annuals in temperate regions for only one growing season.
(Plant village n.d, Swamy, 2023)

Cultivars commonly grown in Kenya: 

Sweet pepper (C. annuum):

• California Wonder
• Yolo wonder
• Emerald Giant
• Ruby Giant

Hot pepper 

• Anaheim
• Fresno
• Jalapeno
• Long Red Cayenne
• Rocket
• Short Bullet

Ecological Information

Climatic requirements and cultural practices for production of sweet peppers and chillies are the same. They also share a same complex of pests and diseases. Capsicum peppers tend to tolerate shade conditions up to 45% of prevailing solar radiation, although shade may delay flowering. Capsicum peppers grow best on well-drained loamy soils at pH 5.5-6.8. They grow at a wide range of altitudes, with rainfall between 600 and 1250 mm. Severe flooding or drought is injurious to most cultivars. Seeds germinate best at 25-30°C. Optimal temperatures for productivity are between 18 and 30°C. C. frutescens are more tolerant to high temperatures. Cooler night temperatures down to 15°C favour fruit setting, although flowering will be delayed as temperatures drop below 25°C. Flower buds will usually abort rather than develop to maturity if night temperatures reach 30°C. Pollen viability is significantly reduced at temperatures above 30°C and below 15°C. 

Agronomic aspects

Capsicum peppers are propagated by seed. Seeds should be harvested from mature fresh fruit after 2 weeks of ripening after harvest. Seeds remain viable for 2-3 years without special conservation methods if they are kept dry. They rapidly lose viability if they are not properly stored especially at high temperature or humidity. Seed dormancy may occur to a small extent, especially if seed is harvested from under-ripe fruits. Some 200-800 g of seed is required per ha, depending on plant density. When using own seeds, hot-water treat the seeds. 

For information on hot-water treatment of seeds click here. 

Seedbeds are usually covered with straw, leaves or protective tunnels. For better production, seedlings should be transferred to seedling pots (plastic pots, paper cups, banana leaf-rolls, etc.) when the cotyledons are fully expanded. Transplants are planted out in the field at the 8-10 true leaf stage, usually 30-40 days after sowing. Hardy transplants can be produced by restricting water and removing shade protection, starting 4-7 days before transplanting. Transplanting should be done during cloudy days or in the late afternoon, and should be followed immediately by irrigation. Direct sowing in the field is practised to a limited extent. Capsicum peppers are well adapted to sole cropping and intercropping systems. Capsicum peppers are often relay-cropped with tomatoes, shallots, onions, garlic, okra, Brassica spp. and pulses. They also grow well among newly established perennial crops.  

Capsicum peppers thrive best if supplied with a generous amount of organic matter. A reasonable recommendation is to supply 10-20 t/ha of organic matter. General nutrient requirements are 130 kg/ha of N, 80 kg/ha of P and 110 kg/ha of K. Nutrient availability is subject to soil type and environmental conditions, so local recommendations vary. Manual weeding is usual for weed control. It is most critical at the reproductive phase. Organic or plastic mulches are very effective for weed control, and reflective mulches help to minimise insect vectors of plant viruses. Staking can help minimise lodging. Capsicum peppers may be grown under rain-fed or irrigated conditions. To avoid certain diseases, pests or allelopathic damage, capsicum peppers should not be planted after other solanaceous crops, sweet potato or jute. 

Harvest, post-harvest practices and markets 

Harvesting

Peppers are typically ready for harvesting approximately 2 months after transplanting, though the exact timing can vary based on the pepper types, season and the fruit maturity desired.  Harvest maturity is determined using various criteria which vary based on the pepper types. The most common indicator of fruit maturity is the size of the pepper which should be fully developed, reach its expected size for the particular variety, and exhibit a frim, thick wall and a shiny skin. Green fruits are mature when firm, if gently squeezed they make a characteristic popping sound.
The pepper's external color is another important indicator. The decision on when to harvest depends on market color preferences. Sweet capsicum peppers are often harvested at the green mature stage, although sometimes they are harvested red. Assorted fruit colors such as yellow, orange, chocolate and purple are also available in specialized markets. Hot capsicum peppers are harvested green or red depending on their utilization. For the fresh market, fruits are harvested mature but firm, whereas capsicum peppers sold as dried pods may be left to partially dry on the plants before harvesting. 
Harvesting is done by hand, gently holding the fruit and snapping it off the plant or using a small knife. The fruits are harvested once per week preferably in the cooler hours of the day. Avoid harvesting when peppers are wet to prevent decay. Remove peppers with skin injuries and any diseased fruit separately from the healthy ones. Use wide, shallow, stackable plastic containers with smooth surfaces for protection. These should be cleaned daily to prevent disease buildup. If using wooden crates or straw baskets, line them with newspapers to minimize fruit abrasion. Avoid canvas or nylon sacks. Keep harvested peppers cool and shaded. Avoid tightly packing or exposing peppers to direct sunlight, as high temperatures reduce shelf life. Handle peppers carefully throughout to prevent any bruising or punctures which may cause decay. Yields under irrigated conditions tend to be higher than for rain-fed production, but vary with other management practices. Sun-drying usually takes place in a vacant field or roadside, on mats or a well-swept area. In the sun, capsicum peppers will dry adequately in 10-20 days, with frequent turning of fruits. Steaming of hot and capsicum pepper before being sun-dried tends to improve the appearance, making dried fruits look glossy.
(NGMC & NARI, 2003, CABI, 2005)

Postharvest practices 
Peppers are graded both in the field during harvest and at packing. Initial grading in the field involves separating damaged or unmarketable peppers from those suitable for marketing. At packing house, further grading based on size, shape, color, appearance and the presence of surface defects is carried out. 
Unless sold for the fresh market, hot capsicum peppers can be sun-dried. In the sun, capsicum peppers will dry adequately in 10-20 days, with frequent turning of fruits. Steaming of hot and capsicum pepper before being sun-dried tends to improve the appearance, making dried fruits look glossy. Fresh fruits can maintain their quality for as long as five weeks when stored at 4°C with a humidity level of 95%. Dried capsicum, on the other hand, can be stored for several months to meet the demand throughout the year.
The primary postharvest diseases in peppers include bacterial soft rot, gray mold, rhizopus rot, watery soft rot, black mold, anthracnose, and sour rot. These diseases are more common in wet, rainy conditions. To reduce their occurrence, it's crucial to implement effective pre-harvest disease control methods, handle, clean, and grade the peppers carefully, and maintain proper postharvest temperature control
(NGMC & NARI, 2003, CABI, 2005, Grubben et al., 2004)

Nutritional value

Capsicum annuum (sweet and chili), offer a variety of nutritional benefits and are renowned for their diverse range of flavors and spiciness. They can be enjoyed raw in salads, stuffed, sautéed, roasted, or added to various dishes like stir-fries, soups, and omelets.
Peppers are relatively low in calories, making them a healthy addition to a balanced diet, especially if you're trying to manage your weight. The fruits are exceptionally high in vitamin C, which is essential for immune function, skin health, and wound healing. Peppers, especially orange and red varieties, are high in beta-carotene, which the body can convert into vitamin A. Vitamin A is crucial for vision, immune function, and skin health. Peppers also contain vitamin B6, vitamin K, and vitamin E in varying amounts.
Peppers contain essential minerals such as potassium and folate. Potassium is important for regulating blood pressure, while folate is vital for cell division and DNA synthesis. They are also packed with antioxidants like flavonoids and carotenoids, including beta-carotene, lutein, and zeaxanthin. These compounds help protect cells from damage caused by free radicals, reducing the risk of chronic diseases.
Capsaicin, a compound found in hot peppers, has anti-inflammatory properties and may help alleviate pain and discomfort associated with conditions like arthritis and muscle aches. Other health benefits associated with the compounds include improved metabolism, and appetite control.
Note: The nutritional content of peppers can vary slightly depending on the color and ripeness. For instance, red peppers tend to have more vitamin C and beta-carotene than green peppers, which are harvested before fully ripening.
(Healthline n.d, Swamy, 2023, WebMD, 2022)
Table 1: Proximate nutritional value per 100g edible portion

Source (Nutrient data): West African food composition table (Stadlmayr, 2012)

^$ Draining the water several times leaches away water soluble nutrients significantly.

^a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO

^b NHS (refers to saturated fat)

^c https://www.hsph.harvard.edu/nutritionsource/water/

^d British Heart Foundation

^e FDA

^f NIH

^g Mayo Clinic

^h For pregnancy and lactation, the amount increases to 1.9 mg and 2.0 mg, respectively

Nutritive Value per 100 g of edible Portion