Technically a walnut is the seed of a drupe or drupaceous nut, and thus not a true botanical nut.
Walnuts are one of the oldest tree food known to man, dating back to 7000 B.C.
The Romans called walnuts Juglans regia, “Jupiter’s royal acorn.”
Early history indicates that English walnuts came from ancient Persia, where they were reserved for royalty. Thus, the walnut is often known as the “Persian Walnut.”
Walnuts were traded along the Silk Road route between Asia and the Middle East. Caravans carried walnuts to far off lands and eventually through sea trade, spreading the popularity of the walnut around the world.
English merchant marines transported the product for trade to ports around the world and they became known as “English Walnuts.” England, in fact, never grew walnuts commercially.
Walnut tree is a large, deciduous tree attaining heights of 25–35 meters (80 to 120 feet), and a trunk up to 2 meters (6 feet) diameter, commonly with a short trunk and broad crown, though taller and narrower in dense forest competition. It is a light-demanding species, requiring full sun to grow well.
The bark is smooth, olive-brown when young and silvery-grey on older branches, and features scattered broad fissures with a rougher texture.
The leaves are alternately arranged, 25–40 cm (10 to 16 in) long, odd-pinnate with 5–9 leaflets, paired alternately with one terminal leaflet.
The male flowers are in drooping catkins 5–10 cm (2 to 4 in) long, and the female flowers are terminal, in clusters of two to five, ripening in the autumn into a fruit with a green, semifleshy husk and a brown, corrugated nut.
The whole fruit, including the husk, falls in autumn; the seed is large, with a relatively thin shell, and edible, with a rich flavour.
Walnuts are among the most nutritious of all nuts. There are 654 calories in 100 grams (3.5 ounces) of walnuts.
Walnuts are an excellent source of anti-inflammatory omega-3 essential fatty acids. They are also rich in antioxidants, including being a very good source of manganese and copper. Walnuts are also a good source of molybdenum, vitamin E, B-complex vitamins, ellagitannins, catechin and melatonin. Many other minerals are provided by walnuts in valuable amounts. These minerals include calcium, chromium, iron, magnesium, phosphorus, potassium, selenium, vanadium and zinc.
Some of the health benefits of walnuts include a reduction of bad cholesterol in the body, an improvement in metabolism, and control of diabetes. They also good for anti-inflammatory properties, aid in weight management, and help as a mood booster. They are also believed to slow down the spread of cancer.
Dr Joe Vinson, from the University of Scranton, analysed the antioxidant levels of nine different types of nuts and discovered that a handful of walnuts contained twice as many antioxidants as a handful of any other commonly eaten nut.
Walnuts can be consumed as snack, or as a part of various desserts and salty dishes.
Walnut oil is available commercially and is chiefly used as a food ingredient particularly in salad dressings.
Walnuts have always been considered as “Brain Food”, perhaps because the surface structure of the walnut has a crinkly appearance like that of the brain. Due to this reason, they have been considered as a symbol of intelligence, leading to the belief that they actually increase one’s intellect. While this is not exactly true, recent studies have proven that the consumption of these seeds does help in promoting brain function.
China is the largest producer of walnuts in the world, producing nearly half of the global walnut supply.
The United States is the second largest producer of walnuts, accounting for approximately one third of the total world production. California is the nation’s numberone walnut producer, accounting for nearly all walnuts produced in the U.S.
Although commercial walnut orchards usually have a life expectancy of 60-100 years, in favourable circumstances walnut trees can live for 300 years or more.
The word “walnut” derives from Old English wealhhnutu, literally “foreign nut,” with wealh meaning “foreign.” The walnut was so called because it was introduced from Gaul and Italy. The previous Latin name for the walnut was nux Gallica, “Gallic nut.”
In China, pairs of walnuts have traditionally been rotated and played with in the palm of the hand, both as a means to stimulate blood circulation and as a status symbol. Individual and pairs of large, old, symmetrically shaped, and sometimes intricately carved walnuts are valued highly and have recently been used as an investment, with some of them fetching tens of thousands of dollars.
The most walnuts crushed by the hand in one minute is 212, achieved by Prabhakar Reddy P, (India), in Andhra Pradesh, India, on 13 August 2017. Prabhakar beat the previous record by just one verified crushed walnut.
The most walnuts cracked against the head in one minute is 181 and was achieved by Muhammed Rashid (Pakistan), in Udine, Italy, on 17 April 2016.