Walnut oil

Walnut oil is oil extracted from walnuts Juglans regia (Persian walnuts). Each 100 g of oil provides about 63.3 g polyunsaturated fatty acids, 22.8 g monounsaturated fats, and 9.1 g saturated fats. It contains no cholesterol.

Unlike most nuts that are high in monounsaturated fatty acids, walnut oil is composed largely of polyunsaturated fatty acids (72% of total fats), particularly alpha-linolenic acid (14%) and linoleic acid (58%), although it does contain oleic acid as 13% of total fats.

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.

Over 99% of walnut oil sold in the USA is produced in California. There are also producers in China, Iran, Mexico, France, Romania, Moldova, Ukraine, Turkey, Australia, New Zealand.

There are two types of walnut oil commercially available: cold pressed and refined. Cold pressed walnut oil is typically more expensive due to the loss of a higher percentage of the oil. Refined walnut oil is expeller pressed and saturated with solvent to extract the highest percentage of oil available in the nut meat. The solvents are subsequently eliminated by heating the mixture to around 400 °F (200 °C). Both methods produce food grade culinary oils.

...
Wikipedia