Capsicum annuum L. (Sweet pepper, Bell Pepper / Chili Pepper)
Sweet pepper (Capsicum annuum L.)
Sweet pepper is an annual horticultural crop widely cultivated in many countries with temperate, subtropical and Mediterranean climates. The plant has an herbaceous habit, with an erect, branched stem and alternate leaves, ovate to lanceolate in shape and generally dark green in colour. Flowers are solitary or borne in small clusters, with a whitish or greenish corolla. The fruit is a hollow, fleshy berry, highly variable in shape, size and colour: it may be elongated, blocky, conical or rounded, and can appear green, yellow, orange or red, depending on the cultivar and the ripening stage.
From a cultivation perspective, sweet pepper requires mild temperatures and good light availability, with optimal growth conditions between 20 and 30 °C. It is sensitive to temperatures below 12–14 °C and to prolonged heat stress, both of which may impair fruit set. The crop prefers well-drained soils of medium texture, rich in organic matter, with a slightly acidic to neutral pH. Water management must be regular and balanced, avoiding both drought stress and waterlogging, which can promote rots and physiological disorders. Factors such as balanced fertilization, planting density, cultivar selection and prevailing climatic conditions significantly affect yield and commercial quality.
The fruit composition is characterised by a high water content, followed by carbohydrates and a fraction of dietary fibre. Sweet pepper provides potassium, smaller amounts of calcium and magnesium, and a variable range of bioactive compounds such as carotenoids, flavonoids and, in pungent types, capsaicinoids. It is also a source of vitamins, both water-soluble and fat-soluble. The presence of capsaicin in hot cultivars underlies the pungent sensation and the technological and culinary interest associated with these fruits. The levels of nutrients and phytochemicals vary according to cultivar, pedoclimatic conditions, maturity stage and crop management.
From a food and technological standpoint, sweet pepper is consumed fresh, either raw or cooked, and is a highly versatile ingredient in many culinary preparations. It can be preserved by drying, freezing, fermentation or processed into sauces, preserves, pastes and other industrial products. Colour, aroma, flesh firmness, absence of defects, size uniformity and intact skin are key parameters in commercial evaluation. The different types (sweet or hot; elongated, blocky or conical fruit) are suited to specific market demands and are used both for fresh consumption and for industrial processing.
Botanical classification (APG IV system)
Common name: Bell pepper
Botanical name: Capsicum annuum L.
Kingdom: Plantae
Clade: Angiosperms → Eudicots → Asterids
Order: Solanales
Family: Solanaceae
Genus: Capsicum
Species: Capsicum annuum L.
Indicative nutritional values per 100 g (raw edible portion)
| Component | Approx. value per 100 g |
|---|---|
| Energy | ~ 26–31 kcal |
| Total carbohydrates | ~ 6.0–6.5 g |
| — of which sugars | ~ 4.0–4.5 g |
| Dietary fibre | ~ 1.5–2.1 g |
| Proteins | ~ 0.9–1.2 g |
| Total fats | ~ 0.2–0.4 g |
| — of which saturated fatty acids (SFA) | trace |
| — monounsaturated (MUFA) | trace |
| — polyunsaturated (PUFA) | trace |
| Sodium | very low |
| Potassium | ~ 210–220 mg |
| Calcium | ~ 8–12 mg |
| Magnesium | ~ 10–12 mg |
| Phosphorus | ~ 20–25 mg |
| Iron | ~ 0.3–0.5 mg |
| Vitamin C | ~ 80–120 mg (depending on colour and ripeness) |
| B-group vitamins (e.g., B6, folates) | small amounts |
| Vitamin A (β-carotene) | higher in red peppers |
Values may vary depending on cultivar, colour, ripeness stage and agronomic conditions.
Mini-glossary of acronyms
SFA = Saturated fatty acids. When they largely replace unsaturated fats in the diet, their intake is associated with a less favourable cardiovascular profile.
MUFA = Monounsaturated fatty acids. Generally considered beneficial when replacing saturated fats.
PUFA = Polyunsaturated fatty acids. Include omega-6 and omega-3, essential in small amounts and involved in membrane structure and inflammatory balance.
Plant characteristics
Habit: Annual herb (in temperate climates) or perennial (in tropical zones), 40–100 cm tall, with an erect, branched stem.
Leaves: Alternate, ovate to lanceolate, smooth, and bright green.
Flowers: Solitary or in small clusters, white or greenish, hermaphroditic, insect-pollinated.
Fruits: Pendulous or erect berries of variable shape and color (red, yellow, orange, green, or purple); smooth or wrinkled surface; sweet or pungent flavor.
Seeds: Flat, pale yellow, numerous, contained in the central placenta of the fruit.
Roots: Taproot system, branched and sensitive to excess moisture.
Chemical composition (main constituents of the fruit)
Vitamin C: very high content (up to 150–200 mg/100 g in ripe red peppers).
Carotenoids: capsanthin, capsorubin, β-carotene, and lutein — natural antioxidants and precursors of vitamin A.
Capsaicinoids: capsaicin and dihydrocapsaicin (in hot varieties), responsible for pungency and local stimulating effects.
Flavonoids: quercetin, luteolin, apigenin — with antioxidant and vasoprotective activity.
B vitamins and vitamin E: contribute to metabolic and cellular protection.
Minerals: potassium, magnesium, iron, phosphorus, and zinc.
Dietary fiber and water (over 85%), promoting digestion and hydration.
Cultivation and growing conditions
Climate: Warm-temperate; sensitive to frost and cold.
Exposure: Full sun is essential for fruit development and color intensity.
Soil: Fertile, well-drained, rich in organic matter; pH 6–7.
Irrigation: Regular, avoiding waterlogging; drought reduces fruit size and quality.
Sowing and transplanting: From February to May; transplant once temperatures exceed 15 °C.
Harvesting: 60–90 days after transplanting, depending on the variety and ripeness stage.
Crop rotation: Avoid planting after other Solanaceae (tomato, potato, eggplant) to prevent soil diseases.
Uses and benefits (traditional and supported by preliminary scientific evidence)
Antioxidant and protective: due to its high content of vitamin C, carotenoids, and flavonoids.
Digestive and metabolic stimulant: enhances gastric secretion and fat metabolism.
Anti-inflammatory and analgesic: topical capsaicin reduces muscle and joint pain.
Vasodilator and circulatory tonic: supports peripheral microcirculation.
Depurative and mildly diuretic: promotes fluid elimination and detoxification.
Scientific studies have confirmed the benefits of capsaicin in reducing neuropathic pain and improving lipid metabolism, though concentrated preparations must be used carefully.
Applications
Food: Consumed fresh or cooked; used in sauces, preserves, oils, and spices (paprika, chili powder).
Herbal medicine: Extracts and oleoresins containing capsaicin in stimulating or warming formulations.
Cosmetics: Used in warming or toning ointments and creams.
Phytotherapy: Adjuvant in the treatment of muscular pain and joint stiffness.
Ornamental: Compact, colorful varieties cultivated as decorative plants.
Harvesting and processing
Harvesting: Manual or mechanical when fruits reach full color and maturity.
Drying: Natural or controlled drying for spice and powder production.
Grinding: For paprika or chili powder preparation.
Extraction: Natural or CO₂ solvent extraction for oleoresins and standardized extracts.
Storage: In cool, dry, and dark conditions to preserve pigments and aroma.
Environmental considerations
Capsicum annuum is a nutrient-rich crop but susceptible to pests and fungal diseases. Integrated or organic farming practices, crop rotation, and limited pesticide use are recommended.
Greenhouse and potted cultivation allow extended harvest periods and contribute to sustainable vegetable production.
Safety, contraindications, interactions
Generally safe in normal dietary amounts.
Capsaicin: Excessive intake may cause burning, gastritis, or skin irritation.
Contraindicated: In gastric ulcers, hemorrhoids, or gastrointestinal inflammation.
Topical use: Avoid application on broken or sensitive skin.
Allergies: Rare, but possible in individuals sensitive to Solanaceae.
Pregnancy and lactation: Moderate dietary consumption considered safe.
Common preparations (general, non-therapeutic use)
Fresh or cooked: Used in salads, sauces, roasted dishes, and stuffed recipes.
Chili powder: As a spice or condiment for sauces and preserved foods.
Digestive infusion (traditional): A small amount of chili in hot water to stimulate digestion.
Capsaicin ointments: Topical preparations for muscle or rheumatic pain relief.
Fresh pepper contains phenols, flavonoids, capsaicinoids, ascorbic acid, all components that exert an antioxidant activity. In the treated pepper there are fewer phytochemical components and the antioxidant activity is lower (1). Cooking the pepper subtracts at least 60% of vitamin C.
Capsaicin is the alkaloid that gives the pepper its spicy taste, it is a component with antioxidant properties.
An extract from the leaves of pepper significantly inhibited inflammatory cytokine production, inhibited cell proliferation without producing cytotoxicity, and suppressed the expression of inflammatory proteins (2).
Among the polyphenols present, caffeic acid, quercetin and kaempferol have the highest amounts and have shown antimicrobial activity (3).
From green bell pepper, an extract of pectic polysaccharides showed antineoplastic activity in breast cancer, in vitro and in vivo (4).
