Walnut

Walnut
Juglans regia L.
Family Juglandaceae A. Rich. et Kunth.

Description of Walnut

The walnut tree is a large deciduous tree, reaching up to 30 m or more in height, with a straight trunk up to 1.5 m in diameter. Older trunks are covered with cracked dark gray bark, while younger ones have smooth light gray bark, and young branches are glossy, ranging from olive-green to brown. It forms a wide, spreading, sparse crown and has a powerful root system.
Walnut leaves are aromatic, alternate, long-petioled, compound, very large, 15–60 cm long, odd-pinnate, with 2–5 pairs of elongated-ovate or elliptical leaflets, 5–15 cm long and 2.5–8 cm wide. The leaflet base is slightly cordate, the apex blunt or pointed, the margin entire or slightly toothed, with the upper unpaired leaflet larger than the lateral ones. They are glabrous and dark green on the upper side, pubescent along the veins and lighter on the underside; leaves of sprout shoots are often multipinnate.
Walnut flowers are inconspicuous, small, and unisexual; male flowers are in many-flowered, large, hanging, cylindrical, green catkins, 8–12 cm long, with 20–30 stamens in the lower flowers of the inflorescence and 6–8 in the upper ones; female flowers are solitary or gathered in racemes of 2–3 (5) at the tips of annual branches, green, with a four-lobed perianth, a pistil with two purple fringed stigmas; the ovary is unilocular with false septa.
The walnut fruit is a false drupe up to 5 cm long and 3 cm wide with a green, leathery-fleshy, glabrous pericarp, bluntly ribbed on the sides, blackening and lignifying, cracking and separating upon ripening. This outer part is called the exocarp. From the separating exocarp falls the incompletely 2–4-locular, so-called walnut, up to 45 mm long and 35 mm in diameter; its shape varies greatly in roundness, from oval to spherical. The walnut shell (endocarp) also varies in thickness and hardness; it is whitish-brown, woody, hard, with a dull, unevenly pitted, reticulate-wrinkled surface covered with a network of groove-like depressions—traces of vascular bundles—with large ribs and a pointed apex; the inner surface of the shell is more or less unevenly folded to fold-pitted, rarely almost smooth.
The walnut seed (kernel or nut meat) is without endosperm, lobed due to division by fruit septa, and unevenly folded, cerebriform—corresponding to the irregularities of the inner surface of the shell; it is covered with a thin, membranous light brown skin.
It blooms in April–May when leaves unfurl.
Walnut fruits ripen in August–September.
There are many varieties that differ in nut shape (oval, elongated-conical), size (large, medium, small), shell thickness (thick- and thin-shelled, soft- and hard-shelled), septum structure, etc. Internationally known varieties include: 'Chandler', 'Hartley', 'Franquette', 'Howard', 'Mayette', 'Payne', 'Serr'.
Manchurian Walnut (J. manshurica Maxim.) differs with a looser crown, more leaflets per leaf (9–21) with a strongly elongated apex, dirty brown nuts of a cigar-like shape, up to 5 cm long, having an abrupt short point, 6–8 longitudinal, pointed ribs with large wrinkles between them. The shell is very thick and hard, deeply pitted, so the kernel is difficult to extract and can only be removed in small pieces; the seed is small, rich in oil. It is widespread in Primorye (its western range boundary is the Zel River), Amur region, North Korea, and Northeast China in mixed forests, along river valleys, and adjacent slopes. Kernel yield is about 15% of the nut's weight. A small amount of alkaloids, essential oil, tannins are found in young leaves, and fresh leaves contain up to 1720 mg% ascorbic acid. The pericarp contains up to 14% tannins. The oil content in the kernel is high – averaging 55%. The bark contains: 5.1% tannins, the shell – up to 30%. The phloem of the Manchurian walnut is used as an analgesic and wound-healing agent; the tree bark is used to treat acute bacterial dysentery; a decoction of leaves promotes glucose absorption by the body and is used as an auxiliary agent for diabetes; a decoction and infusion of leaves and pericarps are used as an astringent. The oil is suitable for food and technical purposes.
Butternut (J. cinerea), a North American butternut, is often cultivated in the middle and southern belts. Its fruit is elongated-ovate, dark brown, with a thick shell and a small, oil-rich kernel. It is used in homeopathy: an essence is prepared from the inner layer of the fresh bark of its branches, trunks, and roots.

 

Habitat and Ecology of Walnut

The homeland of the walnut is the Balkans, Central and Asia Minor, Iran, Afghanistan. It is cultivated in Europe, the Caucasus, Central Asia, China, North America, and Australia. It grows in mixed forests, along streams, and on slopes (up to 2000 m). It prefers deep, fertile soils (pH 6.0–7.5), temperatures of 15–25 °C, watering with 20–30 L/tree every 10 days, and does not tolerate frosts below -25 °C. It propagates by seeds and grafting. Yield: 2–3 t/ha. Care includes: pruning, fertilizing with potassium and phosphorus (30–50 g/tree), and protection against the walnut husk fly. Ecologically, it enriches the soil and repels insects (juglone).

 

Walnut Raw Materials

Raw materials: leaves (folia Juglandis), pericarps (cortex Juglandis fructus), unripe fruits (fructus Juglandis), kernels (semen Juglandis). Leaves are collected in spring and early summer (May–June), during flowering, when they have reached normal size but have not yet fully developed and are covered with essential oil glands, possessing a balsamic scent. They are plucked or broken off and placed in baskets or bags, then the leaflets are removed from the central petiole. Leaves should not be collected wet, with dew or after rain, as they turn black during drying. They are dried at a temperature of 30–35 °C under sheds, in attics, or in dryers, spread in a thin layer (2–3 cm) on cloth or paper, stirring periodically. Blackened leaflets are discarded. The yield of dry raw material is 23–25%. The raw material consists of individual leaflets up to 15 cm long and 6 cm wide, dark green on top, lighter on the bottom, with a spicy aroma and an astringent, slightly bitter taste. Moisture content not higher than <13 %, browned and blackened leaves not more than 5 %, other parts of the nut not more than 5 %, comminuted parts (sieve with 3 mm holes) not more than 3 %, organic impurities not more than 0.5 %, mineral impurities not more than 0.5 %. Pack in bales of 50 kg, store in wooden boxes lined with paper, in dry, ventilated rooms.
Pericarps and unripe fruits are collected in August–September, cut in half, blackened parts removed, and dried at 30–40 °C in a warm room or dryers. The raw material consists of pericarps cut in half, dark brown in color, odorless, with a bitter-astringent taste. Yield 20 %. Moisture content not more than <14 %, blackened pericarps not more than 5 %, other parts (shell, leaves, flowers) not more than 1 %, parts of other plants not more than 1 %, mineral impurities not more than 0.5 %. Kernels are extracted from mature nuts, dried at 25–30 °C (yield 40–50 %). Quality: kernels are light, moisture <13 %. Store in airtight containers (leaves/pericarps: 1 year; kernels: 2 years).

 

Chemical Composition of Walnut

Walnut leaves contain: naphthoquinone derivatives (alpha- and beta-hydrojuglones, easily oxidized to juglone (5-hydroxy-1,4-alpha-naphthoquinone) - a yellow dye), phenolic acids (caffeic, p-coumaric), flavonoids (hyperoside, quercetin 3-arabinoside, kaempferol 3-arabinoside, etc.), alkaloid juglandine, ascorbic acid (3 %, maximum in the middle of the growing season), carotene (33 mg %), B vitamins, inositol, gallotannins (up to 5 %), a small amount of gallic and ellagic acids, essential oil (up to 0.03 %), pectins, bitter substances, mineral salts.
Pericarps contain: alpha- and beta-hydrojuglones, ascorbic acid (up to 3 %), tannins (up to 25 %), malic, citric acids, sugars, enzymes.
Unripe fruits contain: up to 2500 mg % ascorbic acid, fatty oil, beta-sitosterol, sugars, starch.
Kernels contain: up to 80 % fatty oil (glycerides of unsaturated fatty acids: linoleic 56–64 %, oleic 14–28 %, linolenic 7–13 %; saturated fatty acids: stearic, palmitic, not more than 10 %), carbohydrates (up to 7 %), easily digestible proteins (12–23 %, especially arginine, histidine), alpha-tocopherol (up to 73 mg %), B vitamins, fiber, iron and cobalt salts. Caloric content of kernels: 650–700 kcal/100 g.

 

Action and Application of Walnut

Walnut possesses bactericidal, anti-inflammatory, wound-healing, hemostatic, anthelmintic, hypoglycemic, analgesic, antitussive, antiseptic, and astringent properties. Juglone is attributed with bactericidal and fungistatic properties, effective in skin tuberculosis, eczema, and periodontitis. Flavonoids, tannins, and ascorbic acid provide wound-healing, anti-inflammatory, and hemostatic effects. Leaves and pericarps are used for diabetes, gastritis, diarrhea, eczema, acne, hemorrhoids, avitaminosis, jaundice, gout, furunculosis, pyoderma, herpetiform dermatitis, lymphatic diathesis, and menstrual irregularities. Kernels are used for atherosclerosis, anemia, hypertension, recovery after illness, increased acidity, anemia, for breastfeeding mothers, and to improve spermatogenesis and intestinal peristalsis. The juice of unripe fruits and oil treat burns, strengthen hair, and are used for eye diseases. Leaf infusions are used for gargling with angina, periodontitis, inflammation of lymph nodes, gums, for baths in skin diseases, joint pain, rickets, scrofula. A decoction of leaves is used as compresses for hemorrhoids, eczema, and cervical gland tumors. Walnut milk is a source of arginine for liquid diets. Crushed kernels with honey are recommended for tuberculosis and debilitating diseases. A decoction of pericarps is used for expelling worms and treating hemorrhoidal bleeding. In homeopathy, an essence from pericarps and leaves is used for uterine bleeding. Powdered root bark is a laxative.

 

Precautions for Walnut Use

Excessive kernels (over 100 g/day) or infusion (over 200 ml/day) can cause allergies (urticaria, Quincke's edema, allergic stomatitis, diathesis) or dyspepsia. External application of juice (more than 10 ml) can provoke dermatitis. Store raw materials at <13 % humidity. For children under 3 years old, give ≤10 g/day of kernels. Do not combine with antibiotics without consulting a doctor.

 

Contraindications for Walnut Use

Eczema, psoriasis, neurodermatitis, allergy to Juglandaceae, ulcerative colitis, enterocolitis, children under 1 year of age.

 

Walnut Recipes

1. Leaf Tea for Scurvy, Diabetes, Worms, Skin Diseases. 1 tablespoon chopped leaves per 1 glass boiling water, infuse 10 min, drink 1 tablespoon 2–3 times a day.
2. Leaf Tea for Skin & Venereal Diseases, Worms, GI Catarrh, Enterocolitis, Blood Sugar Reduction. 50 g leaves per 1 L water, drink.
3. Leaf Infusion for Diabetes. 1 tablespoon crushed leaves, 2 glasses boiling water, infuse 2 hours, take 1 tablespoon 2–3 times a day before meals.
4. Leaf Infusion for Diathesis & Rickets (5:200 ratio). Take 1 dessert spoon 3 times a day.
5. Leaf Infusion for Scrofula & Rickets (children) and Oral/Throat Inflammation. 1 tablespoon leaves, 1 glass boiling water, infuse 2 hours in closed container, strain, give children 1 teaspoon 3 times a day; use for gargling.
6. Leaf Infusion for Digestive Tract Diseases (20:200 ratio). Recommended as bactericidal, astringent, and anti-inflammatory for stomach catarrh, esophagitis, diarrhea, intestinal bleeding, and avitaminosis (especially vitamin C deficiency); take 1 tablespoon 3 times a day.
7. Leaf Infusion for Astringent, Oral Hemorrhage, Vitamin Supplement. 1 tablespoon crushed leaves, 2 glasses boiling water, infuse 1 hour; take 1 tablespoon every 2 hours as an astringent (for intestinal catarrh) or for rinsing mouth and throat for hemorrhages and bleeding gums, as a vitamin supplement for muscle weakness.
8. Leaf Infusion for Gastritis & Colitis. 2 tablespoons leaves, 0.5 L boiling water OR 4–5 tablespoons per 1 L boiling water, infuse 6 hours in a thermos, drink 2–3 glasses a day.
9. Dried Leaf Tea. 3 teaspoons dried leaves, 2 glasses boiling water, infuse. Drink in several sips as tea.
10. Dried Chopped Leaf Infusion (internal). 1 tablespoon dried, finely chopped leaves, 1 glass boiling water, infuse for internal use; drink throughout the day.
11. Leaf Decoction for Children (Rickets, Scrofula, Exudative Diathesis, Lymph Node Inflammation). 5 g leaves per 1 glass water, give children 1 teaspoon or dessert spoon 3 times a day.
12. Dermatosis Treatment for Children. Equal parts walnut leaves and Viola tricolor herb. Prepare hot infusion: 2 teaspoons per 1 glass boiling water – daily dose.
13. Leaf Infusion/Decoction for Baths (Rickets, Scrofula). Apply leaves in an infusion or decoction for baths for rachitic and scrofulous children.
14. Leaf Decoction for Baths/Washing (Joint Diseases, Skin Rashes). 250 g leaves in 1 L water, use for baths, washing.
15. Leaf Decoction for Compresses/Gargling/Douches. 3–5 tablespoons leaves, boil 15 min in 0.5 L boiling water, use for washing, compresses, gargling, and douches.
16. Leaf Poultice for Eczema, Cervical Gland Tumors, Hemorrhoids. Boiled leaves, apply as a poultice.
17. Leaf Decoction for Baths/Washing. 250 g leaves, boil in 1 L water, add to bath or use for washing.
18. External Treatment for Skin Diseases. 0.5–1 kg crushed dried or fresh leaves (mixed with flowers or unripe fruits), 1 bucket (8–10 L) water, boil gently for 30 min, dilute (1:1) with hot water at 37–40 °C, use for baths for skin diseases, neurodermatitis, dry and wet eczema, psoriasis, fungal skin lesions, purulent and atrophic ulcers, insect bite itching. Daily 2–3 baths or lotions.
19. Wart Treatment. Combination of walnut leaves with parsley leaves or roots.
20. Infusion for Female Genital Inflammatory Diseases. 2 tablespoons mixture of walnut leaves (25 g), chamomile flowers, sage leaves (15 g each), oak bark and Malva sylvestris flowers (10 g each), brew 1 L boiling water, use for douches, baths, cotton swabs.
21. Decoction of Dried Fruits for Diabetes & Hypertension. Take 1 tablespoon 3–4 times a day.
22. Chopped Nut Tincture. Chopped nuts infused in ethanol or vodka (1:10 ratio, 50 g raw material per 500 ml vodka), take 30–40 drops 3–4 times a day.
23. Green Nut Tincture for Stomach/Intestinal Inflammation & Indigestion. Approximately 30 finely chopped young fruits, 1 L ethanol or moonshine, infuse in a bottle in the sun for 14 days. The black fragrant tincture is drained, and the remaining nuts are sugared, mixed well, and left to infuse for about a month to produce a good liqueur. A little clove and cinnamon are added to the liqueur to taste. Both the tincture (1 shot glass 3 times a day) and the liqueur are used for inflammation and pain in the stomach and intestines, especially for mild indigestion after meals. The liqueur is less effective but very pleasant to taste.
24. Green Nut Tincture for Gastritis & Diarrhea. 30 chopped green nuts, 1 L 40% ethanol, infuse 15 days – 5–10 ml 3 times a day.
25. Mature Nut Septa Decoction for Diabetes. 40 g septa from mature nuts, simmer in 0.5 L boiling water over low heat for 1 hour – 15 ml 3 times a day.
26. Septa Tincture for Thyrotoxicosis, Diarrhea, Joint Diseases. Tincture of thin septa from 0.5 kg dried nuts in 0.5 L 40% ethanol or wine – 15–20 ml 3 times a day for 1 month.
27. Septa Tincture for Diarrhea, Chronic Colitis, Diabetes, Hypertension. Walnut septa infused in vodka or 40% ethanol (1:10), use for treatment, 20–30 drops 3–4 times a day for 15–30 days.
28. Septa Tincture for Thyroid Gland Diseases. 20% tincture of septa is used.
29. Infusion of Young Leaves or Fruits (internal/external). 20 g chopped young leaves or fruits, 200 ml boiling water, infuse 20 min; drink 1 tablespoon 3 times a day or use externally.
30. Infusion for Acne. 1 tablespoon mixture of walnut leaves, great burdock root, elecampane root, and St. John's wort herb, taken in equal parts, 1 glass boiling water, drink 2–3 glasses a day.
31. Decoction for Purulent Acne. 2 tablespoons mixture of walnut leaves, great burdock root, and tricolor violet herb, taken in equal parts, 0.5 L boiling water, boil 5 min, cool, strain, drink half a glass 4 times a day.
32. Decoction for Night Sweats, Tuberculosis. 1 tablespoon mixture of walnut pericarps, sage leaves, valerian root (25 g each) and field horsetail herb (50 g), boil in 1 glass water for 15 min, drink 3 glasses a day for 2–3 months.
33. Infusion of Leaves or Pericarps. 20 g leaves or pericarps per 200 ml boiling water, 1/3 glass 3 times a day.
34. Treatment for Sweating with Skin Inflammation. Cut off the pericarp from unripe fruits and rub affected areas or rinse with a decoction.
35. Infusion for Excessive Milk Production in Nursing Mothers. 1 teaspoon mixture of walnut leaves (20 g), common hop cones, and sage leaves (40 g each), brew 1 glass boiling water, drink 2–3 glasses a day.
36. Fresh Leaf Poultice for Wounds, Boils, Panaritium. Wash fresh leaves, lightly crush with a blunt object until a thick, viscous, dark green juice flows out; then apply leaves to wounds, boils, or tie to a finger with panaritium as a wound-healing and anti-inflammatory agent.
37. Ointment for Wound Healing. 15 g (1 tablespoon) chopped leaves, 100 g sunflower oil, infuse 7 days, then heat oil with leaves in a boiling water bath for 3 hours, strain twice through gauze, boil the strained mass for 0.5 hour, and add 15 g yellow wax to obtain an ointment.
38. Walnuts for High Stomach Acidity. Eat 25–100 walnuts daily.
39. Walnuts with Honey for Hypertension. Consume 100 g of walnuts with honey for 45 days (can be eaten plain), starting with 3 walnuts a day.
40. Walnut Preserve. Unripe fruits with pericarps, collected in the jelly-kernel stage, after treatment with lime water, lose their bitter taste, then used for jam – a dietary and medicinal product containing large amounts of juglone, ascorbic acid, tannins.
41. Chhonahwan. Walnut kernel – 30 g, psoralea and eucommia fruits – 100 g each, salt – 30 g. Gently grind all components into a powder, make honey balls (0.3 g each), take 5–6 g 3 times a day. Prescribed as a tonic, and for lower back pain.
42. For Vigor. Grind 150 g walnut kernels, add 150 g psoralea and eucommia fruits, grind to a paste, make 0.3 g balls. Take 50 balls on an empty stomach, washing down with warm salted water.
43. For Prolonged Uterine Bleeding. Take 50 walnut kernels, fried so that medicinal properties are preserved, with water.
44. For Wounds and Bruises. Crush walnut kernels, dissolve in water, and drink.
45. For Frequent Urination. Roast walnuts in glowing embers. Take before bedtime with water.
46. For Severe Breathing (Asthma, Cough, Inability to Lie Down). Walnut kernels (without peel), apricot seeds (without peel and pulp), ginger – 38 g each, grind, add evaporated honey, make 0.3 g balls and take before bedtime, chewing thoroughly and washing down with ginseng decoction.
47. For Increased Acidity, Frequent Sour Taste in Mouth. Effectively chew walnuts, washing down with ginger decoction.
48. For Acne. Roast 10 walnuts in glowing embers, then remove shells, gently grind with 32 g sophora flowers, dissolve in warm water, and drink.

 

Walnut Cosmetics

Leaves, pericarps, and oil are used for skin and hair.

1. Hair Dye Decoction. Boil 50 g of leaves in 500 ml of water for 15 minutes, rinse hair, twice a week.
   
2. Skin Mask. 20 g crushed kernels, 10 ml honey, apply for 15 minutes, rinse, twice a week.
   
3. Acne Lotion. Pour 200 ml of boiling water over 20 g of pericarps, infuse for 20 minutes, wipe skin, once a day.
   
4. Hair Oil. Rub 10 ml of walnut oil into the scalp, once a week.
   
5. Hair Darkening Rinse. Boil 1 cup chopped walnut hulls (green or dried) in 4 cups water for 30 minutes. Strain and use as a hair rinse after shampooing for natural darkening.

 

Walnut Culinary Uses

Kernels are used fresh, dried, or roasted.

1. Nut Salad. Mix 50 g kernels, 100 g apples, 50 g raisins, 30 g honey.
   
2. Satsivi (Georgian Chicken with Walnut Sauce). 100 g kernels, 200 g chicken, 50 ml broth, 10 g garlic, spices, stew for 20 min.
   
3. Halva. 200 g kernels, 100 g sugar, 50 ml water, boil 15 min, cool.
   
4. Walnut Milk. 100 g kernels, 300 ml water, grind, strain, drink.
   
5. Walnut Pesto. Blend 1 cup walnuts, 2 cups fresh basil, 2 cloves garlic, 1/2 cup Parmesan cheese, 1/2 cup olive oil, salt, and pepper.
6. Baklava. Layer phyllo dough with a mixture of chopped walnuts, cinnamon, and sugar, then bake and soak in a sweet syrup.
7. Walnut Bread. Incorporate chopped walnuts into your favorite bread dough for a rich, nutty flavor and texture.

Tips: Add kernels to baked goods, store in airtight containers.

 

Other Properties of Walnut

The Common Walnut ( *Juglans regia* ) is a source of pollen for bees, enriches the soil, and repels insects (due to juglone). Its wood is used for furniture, and the bark and leaves are used for tanning leather. A decoction of the leaves can be used against the Colorado potato beetle.