Walnut oil is oil extracted from walnuts, Juglans regia. The oil contains polyunsaturated fatty acids, monounsaturated fatty acids, and saturated fats.
Composition
According to gas chromatographic and
HPLC analysis, virgin walnut oil consists of
linoleic acid (60–62%). It also contains many phenolc compounds including
tocopherol, tanins, and
. Several of these exhibit
antioxidant properties.
[ According to another source, walnut oil is composed largely of polyunsaturated fatty acids (72% of total fats), particularly alpha-linolenic acid (14%) and linoleic acid (58%), oleic acid (13%), and saturated fats (9%).][
]
Walnuts typically contain high concentrations of phenolics including ellagic acid.
Culinary use
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.[
]
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 . Both methods produce food-grade culinary oils. Walnut oil, like all nut, seed and vegetable oils can rancidification.
Over 99% of walnut oil sold in the US is produced in California.
Artistic use
Linoleic acid, the major component of walnut oil, is a "drying oil", which means that in air it polymerizes, forming strong but flexible films, useful in and .
Some Woodworking favour walnut oil as a finish for implements that will come in contact with food, such as wooden bowls, because of its safety. Rancidity is not an issue because walnut oil dries when applied to wood in a thin coating. People who mix oil and wax to formulate wood finishes value walnut oil as an ingredient because of the edibility of both ingredients. The oil typically is combined with beeswax in a mixture of 1/3 oil to 2/3 beeswax.
