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Walnut oil is oil extracted from English walnuts (also known as Persian walnuts). Each 100.0g of oil provides about 63.3g polyunsaturated fatty acids, 22.8g monounsaturated fats, and 9.1g saturated fats. It contains no cholesterol. It is about 60% linoleic acid, an essential polyunsaturated omega-6 fatty acid, and 23-27% monosaturated oleic acid, an omega-9 fatty acid. Walnut oil also contains about .7g per Tbsp (or 1.5g per 100g) of alpha linolenic acid, which supplies the body with needed omega-3 fatty acids, another form of polyunsaturated fats essential to human nutrition.
Walnut oil is edible and is generally used less than other oils in food preparation, often due to high pricing. It is light-coloured and delicate in flavour and scent, with a nutty quality. Although chefs sometimes use walnut oil for pan frying, most avoid walnut oil for high temperature cooking; heating tends to reduce the oil's flavour & nutritive value and to produce a slight bitterness. In addition cooking rapidly destroys the oil's antioxidants. Walnut oil is at its most valuable in cold dishes such as salad dressings, where it lends its flavour to best advantage.
Walnut oil was one of the most important oils used by Renaissance painters. Its short drying time and lack of yellow tint make it a good oil paint base thinner and brush cleaner. However, some practitioners consider walnut oil paint film to be inferior to linseed oil paint film.
Commercially, walnut oil has become hard to find; demand often is low, and stock readily becomes rancid if stored in transparent, warm or ventilated containers. Instead of walnut oil, many artists and stores sell linseed oil, poppyseed oil, and safflower oil as replacements. Recently, the problem of rancidity has been solved with the introduction of commercial alkali refined walnut oil paints and media.
Some woodworkers favour walnut oil as a finish for implements that will come in contact with food, such as cutting boards and wooden bowls. People who mix oil & wax to formulate wood finishes value walnut oil as an ingredient because of its edibility and resistance to oxidation (going rancid). The oil typically is combined with beeswax in a mixture of 1/3 oil to 2/3 beeswax.
- USDA National Nutrient Database for Standard Reference, SR25 (National Nutrient Database for Standard Reference, Release 25 Software v.1.2.2 ) (accessed April 6, 2013); Basic Report: Nutrient data for 04528, Oil, walnut http://ndb.nal.usda.gov/ndb/foods/show/641?qlookup=Walnut+Oil&fg=&format=&man=&lfacet=&max=25&new=1
- "Alpha-linolenic acid". University of Maryland Medical Center.
- "Omega-3 fatty acids". University of Maryland Medical Center.
- "Walnut Storage and Selection". Homecooking.about.com. 2010-08-09. Retrieved 2011-11-10.
- Erik Schimek. "Finishing with Walnut Oil and Beeswax". Erikorganic.com. Retrieved 2011-11-10.