Cultivated for over 2000 years, the walnut tree produces an edible fruit nowadays primarily valued for food but formerly also used to produce dyes and medicines. Although there are about 15 species of walnut the most common varieties are the English walnut, black walnut and the butternut or white walnut. This tree nut is low in saturated fat, high in fiber and protein. It is also a source of antioxidant rich phytochemicals.
The English Walnut (Juglans regia): also know as the wild Persian or royal walnut, the English walnut is the most popular of walnut species. Although it's not native to England, the English walnut gets its name because the British introduced the tree to many of the territories in the former British Empire. The word 'walnut' is an old English word meaning “foreign nut,” which may be a reference to the Gauls (a Celtic people living in Northern France).
English walnuts were probably first cultivated by the Chinese over 2000 years ago and were also widely cultivated by the Ancient Greeks. Later the Roman Empire spread their cultivation throughout Europe, particularly in France, where they were highly valued for walnut oil from the 4th century onwards. To this day walnut oil is more popular than olive oil in France. The term 'noix de Granoble' is an appellation d' origine that applies to the best varieties of French walnuts grown in the Grenoble region.
The English walnut tree is thought native to Southeastern Europe, the Himalayas, Southwestern China and Russia. English walnut trees produce dark green fruits that contain a woody nut, usually in late summer. Juglans regia may be propagated but does not crop well (produce fruit) in cold climates. Walnut crops are usually gathered by hand but a machine (which shakes the tree) is sometimes used. English walnut trees have long been held in high regard as they can live for 300 to 400 hundred years and are large and majestic, reaching heights of 100 feet.
The Black Walnut (juglans nigra): Native to the Appalachians, the Black Walnut is the English walnuts North American cousin. Both types of walnut tree have similar uses, indeed they have been considered the most important and attractive timbers for decorative furniture making since the 17th century and the Queen Anne period. Walnut timber has traditionally been used for wood veneers, gunstocks, rifle butts, paneling and also the fascias of cars.
Butternuts or White Walnuts (Juglans cinerea): the United States is the world's largest producer of walnuts and one of it's most common species is the butternut. Butternuts, which are native to the Eastern Untied States, where used by Native American tribes as a dye plant and for medicinal uses. The Menominee Tribe of Wisconsin extracted brown juice from the husks of butternuts which they used to dye their sheepskin clothing. Indeed, walnut husks were universally used to make hair dyes well into the 20th century. The Butternut or white walnut was also used as a laxative up until the 19th century and is listed in the U.S. Pharmacopeia.
Culinary Uses: walnuts, which are closely related to pecans, are extremely versatile in the kitchen, complementing both appetizer, main course, dessert and also as condiment. However, the walnut is most often associated with baking. It is either ground or chopped as an ingredient or used halved as a decoration. Indeed, the walnut is the second most popular nut in baked items after the almond. Walnuts feature in many world cuisines, from Middle Eastern chicken entrees, to Asian dishes and Italian pesto.
Walnut oil has a strong flavor and is not suitable for preparing certain foods, such as mayonnaise. It is more expensive than extra virgin olive, but like olive oil is suitable for salads. Walnut leaves are used for rapping cheese, (walnut leaves contain antibiotic substances) and also for tea. The husks of walnuts are used for a French liqueur known as brou de noix and there are also walnut flavored wines.
Nutritional Value: An excellent food for vegetarians, walnuts are packed with nutrition. 50g of walnuts has 7.2g of protein, 9.2 of carbohydrate, 2.4g fiber and 31g of fats. They are a good source of copper, magnesium, potassium, phosphorus, vitamin B6, vitamin D, thiamine, folic acid, niacin, iron, riboflavin and pantothenic acid. Because of their high fat content, walnuts are extremely calorific; a 100g serving contains 650 calories. Yet, walnut oil is low in saturated fat (9.1g per 100g) and high in poyunsaturated and monounsaturated fat, making it a healthy alternative. Only canola oil (7.2g per 100g) contains less saturated fat.
Antioxidants: aside from vitamins, minerals, fiber and fatty acids, walnuts are a source of phytochemicals or flavonoids which are non-nutrients commonly found in plants. Flavonoids have positive effects on the body, reducing the risk of chronic diseases such as cancer and diabetes. 100g of walnuts contains 1625 mg of gallic acid, a phytochemical also found in tea, grapes and hops. Walnuts are also a source of pronthocyanidins, (approximately 600 mg/100g) which are oligomeric flavonoids, most commonly found in the skins of grapes and blueberries.
Primary image from flickr.com.