Onion

Onion
Allium cepa L.
Amaryllidaceae Family

Description of Onion

Onion is a perennial bulbous plant, cultivated as biennial. Bulb flattened-spherical or elongated, 5–15 cm in diameter, usually single, sometimes with 2–3 bulbs in sheath. Outer scales (husk) dry, yellow, yellowish-brown, reddish, white or purple; inner fleshy, juicy, white, greenish or purple, arranged spirally-concentrically on shortened stem (bottom). Roots fibrous, thin, unbranched, up to 30 cm. Leaves (feathers) basal, sheathing, tubular, hollow, 20–60 cm long, grayish-green, with waxy coating. Flower arrow hollow, 30–150 cm, swollen below middle. Flowers (50–200) small, up to 1 cm, on pedicels up to 3 cm, gathered in spherical umbel (5–10 cm), greenish or white, sometimes with bulbils, covered by two-leaved wrapper before flowering. Fruit three-celled capsule with 1–6 black, triangular, wrinkled seeds. Flowering in June–August, fruiting in August–September. Varieties: ‘Stuttgarter Riesen’, ‘Red Baron’, ‘Sturon’. Taste: pungent, semi-sweet, sweet.

 

Distribution and Ecology of Onion

Onion originates from Southwest Asia (Iran, Afghanistan, Central and Western India). Not found in the wild, widely cultivated in Europe, Asia, North America, Africa. Prefers loose, fertile soils (pH 6.5–7.5), moderate watering, temperature 15–25 °C, withstands frosts to -5 °C. Propagated by seeds (sow in March–April) or sets (diameter 1–2.5 cm). Yield: 3–5 kg/m². Care: watering (5–10 L/m² every 7 days), nitrogen and potassium feeding (20–30 g/m²), loosening, protection from onion fly and downy mildew. Grown in open ground or greenhouses. Ecologically improves soil, but requires crop rotation to prevent pathogen accumulation.

 

Raw Materials from Onion

Raw materials: bulbs (bulbus Allii cepae) and leaves (folia Allii cepae). Bulbs harvested in August–September, when neck softens and leaves lodge, cleaned, dried at 25–35 °C in ventilated room (yield 80–90%). Leaves cut young (up to 30 cm) in June–July, dried at 30–40 °C (yield 10–15%). Quality: bulbs whole, dry, with neck 2–5 cm, damaged ≤5%, sprouted ≤10%; leaves green, moisture <10%. Store bulbs at 0–3 °C (6–8 months), leaves in airtight containers (1 year). Aroma pungent, onion-like.

 

Chemical Composition of Onion

Bulbs: essential oil (0.005–0.15%, allicin, allyl sulfide, cycloalliin, methylalliin), phytoncides, flavonoids (quercetin, kaempferol), ascorbic acid (10–33 mg%), vitamins (B1 60 mg%, B2 0.02 mg%, nicotinic acid 0.5 mg%), carotene (60 mg%), proteins (2–4.5%), sugars (10–14%, glucose, fructose, sucrose, maltose), pectin, inulin, minerals (K 223 mg%, Ca 1 mg%, Mg 1.2 mg%, Fe 0.04 mg%, manganese, phosphorus, iodine, zinc), protocatechuic, ferulic, citric, malic acids. Leaves: essential oil (0.15%), ascorbic acid (20–90 mg%), carotene (4 mg%), nicotinic acid, proteins (1%), fiber. Calorie content: 40–45 kcal/100 g.

 

Effects and Applications of Onion

Essential oil (allicin, allyl sulfide) has bactericidal, fungicidal, phytoncidal effects, suppresses pathogenic microorganisms. Pectins, mucilages improve digestion, kidney function, intestinal peristalsis. Onion has anti-atheromatous, anti-thrombotic, anti-sclerotic, hypoglycemic, choleretic, protistocidal, mild sedative effects. Used for ARVI, angina, tonsillitis, atherosclerosis, hypertension, diabetes, urolithiasis, colitis with constipation, worms, prostate adenoma, trichomonal colpitis, hypovitaminoses C and B. Juice stimulates spermatogenesis, increases appetite. Pulp treats burns, purulent wounds, mouth ulcers, calluses. Leaves have keratolytic effect. Onion with honey, fried or boiled in milk, helps with cough and bronchitis.

 

Precautions for Using Onion

Raw onion (>100 g/day) may cause stomach irritation, flatulence due to sulfides (propionaldehyde, thiopropanal-S-oxide), which also cause tearing. Juice (>30 ml/day) irritates mucous membranes. Prolonged consumption (more than 2 weeks) may disrupt intestinal microflora. In cardiovascular diseases start with small doses. Store raw materials at humidity <10%. Give children under 3 years ≤20 g/day. Do not combine with anticoagulants or diuretics without doctor's consultation. Reduce tearing when cutting by cooling onion (10 min in refrigerator) or peeling under water.

 

Contraindications for Using Onion

Raw onion and juice contraindicated in peptic ulcer, gastritis with high acidity, pancreatitis, acute kidney and liver diseases, allergy to Allium, children under 1 year.

 

Recipes with Onion

1. Infusion for Atherosclerosis. Grind 100 g onion, pour 200 ml warm water, infuse 8 h, drink 50 ml 3 times a day, 10 days.
   
2. Juice with Honey for Cough. Mix 50 ml juice with 20 g honey, drink 15 ml 3 times a day 20 min before meals, 7 days.
   
3. Pulp for Purulent Wounds. Grind 50 g onion, apply through gauze for 2 h, 1 time a day, 7 days.
   
4. Juice for Worms. Drink 20 ml juice 1 time a day, 7 days.
   
5. Juice for Urolithiasis. Mix 30 ml juice with 30 ml water, drink 2 times a day, 10 days.
   
6. Infusion for Mouth Ulcers. Grind 50 g onion, pour 150 ml boiling water, infuse 1 h, rinse mouth 3 times a day, 5 days.
   

 

Cosmetics from Onion

Juice and husk of onion used to strengthen hair, fight dandruff and improve skin condition.

1. Hair Mask. Rub 20 ml juice into scalp, leave 15 min, rinse, 2 times a week.
   
2. Husk Infusion for Hair. Pour 25 g husk with 500 ml boiling water, infuse 15 min, rinse hair, 1 time a week.
   
3. Skin Lotion. 20 ml juice, 50 ml water, wipe face, 1 time a day.
   
4. Mask for Dandruff. 20 g onion, 10 g honey, apply to scalp for 10 min, rinse, 1 time a week.
   

 

Culinary Uses of Onion

Onion adds aroma and taste to dishes, improves sauces, soups, meat dishes. Consumed fresh, boiled, fried, canned and dried in salads, pies, soups, gravies, mince, sausages, preserves (mushrooms, cucumbers), sauerkraut, cottage cheese, cheese.

1. Onion Soup. 200 g onion, 500 ml broth, 20 g butter, cook 15 min, serve with cheese.
   
2. Salad with Onion. 100 g onion, 100 g cucumbers, 20 ml oil, mix, season with salt.
   
3. Fried Onion. Fry 150 g onion in 20 ml oil until golden, serve as side dish.
   
4. Marinade. 50 g onion, 30 ml vinegar, 10 g spices, marinate meat 2 h.
   

Tips: Cool onion before cutting (10 min in refrigerator) or peel under water to reduce tearing. Coat in flour or sprinkle with powdered sugar for golden color when frying.

 

Other Properties of Onion

Honey plant. Husk contains dye for coloring silk and fabrics yellow-orange. Onion repels insects when planted in gardens.