Walnut Totally Explained

Everything about Juglans totally explained

Walnuts (genus Juglans) are plants in the family Juglandaceae. They are deciduous trees, 10 - 40 meters tall (about 30-130 ft.), with pinnate leaves 200 - 900 millimetres long (about 7-35 inches), with 5 - 25 leaflets; the shoots have chambered pith, a character shared with the wingnuts (Pterocarya) but not the hickories (Carya) in the same family.
The 21 species in the genus range across the north temperate Old World from southeast Europe east to Japan, and more widely in the New World from southeast Canada west to California and south to Argentina. The Latin name Juglans derives from Jovis glans, "Jupiter's acorn": figuratively, a nut fit for a god.
The word walnut derives from Old English wealhhnutu, literally "foreign nut", wealh meaning "foreign" (wealh is akin to the terms and Vlach; see *Walha and History of the term Vlach). 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".

Shells

The walnut shell has a wide variety of uses. It is commonly used as an organic abrasive, to polish and clean a number of different materials. Black walnut shell is the hardest of the walnut shells, and therefore has the highest resistance to break-down. It is environmentally friendly and can be recycled.

Cleansing and polishing: Walnut shells are mostly used to clean soft metals, fiberglass, plastics, wood and stone. Uses include cleaning automobile and jet engines, electronic circuit boards, and paint and graffiti removal. This soft grit abrasive is well suited for air blasting, de-burring, de-scaling, and polishing operations because of its elasticity and resilience. For example: In the early days of jet transportation, crushed walnut shells were used to scour the compressor airfoils clean, but when engines with air cooled vanes and blades in the turbine started being manufactured this practice was stopped. The problem being that the crushed shells tended to plug up the cooling passages to the turbine, resulting in turbine failures due to overheating.

Oil well drilling: The shell is used widely in oil well drilling for lost circulation material in making and maintaining seals in fracture zones and unconsolidated formations.

Paint thickener: Walnut shells are added to paint to give it a thicker consistency for "plaster effect" ranges.

Explosives: Used as a filler in dynamite.

Cosmetic cleaner: Occasionally used in soap and exfoliating cleansers.

Parkland and garden trees

Walnuts are very attractive trees in parks and large gardens. The Japanese Walnut in particular is grown for its huge leaves, which have a 'tropical' appearance.
As garden trees they've some drawbacks, in particular the falling nuts, and the releasing of the allelopathic compound juglone, though a number of gardeners do grow them. However, different walnut species vary in the amount of juglone they release from the roots and fallen leaves - the black walnut in particular is known for its toxicity. Juglone is toxic to plants such as tomato, apple, and birch and may cause stunting and death of nearby vegetation. Juglone appears to be one of the walnut's primary defence mechanisms against potential competitors for resources (water, nutrients and sunlight), and its effects are felt most strongly inside the tree's "drip line" (the circle around the tree marked by the horizontal distance of its outermost branches). However, even plants at a seemingly great distance outside the drip line can be affected, and juglone can linger in the soil for several years even after a walnut is removed as its roots slowly decompose and release juglone into the soil.

Walnut as food plants

Walnuts are used as food plants by the larvae of some Lepidoptera species. These include:

Brown-tail (Euproctis chrysorrhoea)

the Coleophora case-bearers C. laticornella (recorded on J. nigra) and C. pruniella.

Common Emerald (Hemithea aestivaria)

Emperor Moth (Pavonia pavonia)

The Engrailed (Ectropis crepuscularia)

Walnut Sphinx (Amorpha juglandis) In addition, walnuts are a popular snack among woodland creatures, specifically mice and squirrels.

Health aspects of walnuts

A 2006 study published in the Journal of the American College of Cardiology found that eating walnuts after a meal high in unhealthy fats can reduce the damaging effects of such fats on blood vessels. Researchers from Barcelona's Hospital Clinic conducted a study on 24 adult participants, half of whom had normal cholesterol levels, and half of whom had moderately high levels of cholesterol. Each group was fed two high-fat meals of salami and cheese, eaten one week apart. During one meal, the researchers supplemented the food with five teaspoons of olive oil. The researcher added eight shelled walnuts to the other meal, the following week.
   Tests after each meal showed that both the olive oil and the walnuts helped reduce the onset of dangerous inflammation and oxidation in the arteries after the meals, which were high in saturated fat. However, unlike the olive oil, the walnuts also helped the arteries maintain their elasticity and flexibility, even in the participants with higher cholesterol.
   Lead researcher Dr. Emilio Ros said walnuts' protective effects could be because the nuts are high in antioxidants and ALA, a plant-based omega-3 fatty acid. Walnuts also contain arginine, which is an amino acid that the body uses to produce nitric oxide, necessary for keeping blood vessels flexible.
   The latest scientific development has revealed that the plant leaves have the function of reducing fasting blood sugar (FBS) in diabetic rats, of which beta cells could be regenerated, indicating the promising future of the plant for medicinal use.

Walnut extract and Alzheimer's

A 2004 study by the NYS Institute for Basic Research in Developmental Disabilities

(OMRDD) found that walnut extract was able to inhibit and defibrillize (break down) fibrillar amyloid beta protein - the principal component of amyloid plaques in the brains of patients with Alzheimer's. The study looked at the effect of walnut extract on amyloid beta protein fibrillization by Thioflavin T fluorescence spectroscopy and electron microscopy. Similarly, in a study done at Baldwin-Wallace College in Berea, Ohio it was found that two of its major components in walnuts, gallic and ellagic acid, act as "dual-inhibitors" of the enzyme acetylcholinesterase which, in association with amyloid-ß, inhibits protein aggregation, and will also inhibit the site of acetylcholinesterase responsible for the breakdown of acetylcholine.
These results suggest that walnuts may reduce the risk or delay the onset of Alzheimer's disease by maintaining amyloid beta protein in the soluble form and prevent the breakdown of acetylcholine.

Further Information

Get more info on 'Juglans'.

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