Walnut oil

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Walnut oil is oil extracted from walnuts, Juglans regia . The oil contains polyunsaturated fatty acids, monounsaturated fatty acids, and saturated fats. [1] [2]

Contents

Composition

According to gas chromatographic and HPLC analysis, virgin walnut oil consists of linoleic acid (60–62%). It also contains many phenolc compounds including γ-tocopherol, tanins, and flavanoids. Several of these exhibit antioxidant properties. [2] 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%). [1]

Walnuts typically contain high concentrations of phenolics including ellagic acid. [3]

Culinary use

A cup of California roasted walnut oil Walnutoil-cup.jpg
A cup of California roasted walnut oil
Pressing the nuts under high pressure Moulin de Severy 09.jpg
Pressing the nuts under high pressure

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. [4] Although chefs sometimes use walnut oil for pan-frying, most avoid walnut oil for high-temperature cooking because heating tends to reduce the oil's flavour and produce a slight bitterness. Walnut oil is preferred in cold dishes such as salad dressings. [4]

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. Walnut oil, like all nut, seed and vegetable oils can turn rancid.

Over 99% of walnut oil sold in the US is produced in California. [5]

Artistic use

Linoleic acid, the major component of walnut oil, is a "drying oil", which means that in air it polymerizes, forming strong strong but flexible films, useful in oil paints and varnishes. [6] 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.

Some woodworkers 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. [7]

Related Research Articles

<span class="mw-page-title-main">Triglyceride</span> Any ester of glycerol having all three hydroxyl groups esterified with fatty acids

A triglyceride is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and other vertebrates, as well as vegetable fat. They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver, and are a major component of human skin oils.

α-Linolenic acid Chemical compound

α-Linolenic acid, also known as alpha-linolenic acid (ALA), is an n−3, or omega-3, essential fatty acid. ALA is found in many seeds and oils, including flaxseed, walnuts, chia, hemp, and many common vegetable oils.

<span class="mw-page-title-main">Vegetable oil</span> Oil extracted from seeds or from other parts of plants

Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of edible plants. Like animal fats, vegetable fats are mixtures of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or fats from seeds. Olive oil, palm oil, and rice bran oil are examples of fats from other parts of plants. In common usage, vegetable oil may refer exclusively to vegetable fats which are liquid at room temperature. Vegetable oils are usually edible.

<span class="mw-page-title-main">Coconut oil</span> Edible oil derived from coconut

Coconut oil is an edible oil derived from the kernels, meat, and milk of the coconut palm fruit. Coconut oil is a white solid fat below around 25 °C (77 °F), and a clear thin liquid oil in warmer climates. Unrefined varieties have a distinct coconut aroma. Coconut oil is used as a food oil, and in industrial applications for cosmetics and detergent production. The oil is rich in medium-chain fatty acids.

A saturated fat is a type of fat in which the fatty acid chains have all single bonds between the carbon atoms. A fat known as a glyceride is made of two kinds of smaller molecules: a short glycerol backbone and fatty acids that each contain a long linear or branched chain of carbon (C) atoms. Along the chain, some carbon atoms are linked by single bonds (-C-C-) and others are linked by double bonds (-C=C-). A double bond along the carbon chain can react with a pair of hydrogen atoms to change into a single -C-C- bond, with each H atom now bonded to one of the two C atoms. Glyceride fats without any carbon chain double bonds are called saturated because they are "saturated with" hydrogen atoms, having no double bonds available to react with more hydrogen.

<span class="mw-page-title-main">Linseed oil</span> Oil obtained from the dried, ripened seeds of the flax plant

Linseed oil, also known as flaxseed oil or flax oil, is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant. The oil is obtained by pressing, sometimes followed by solvent extraction.

<span class="mw-page-title-main">Hemp oil</span> Oil from hemp seeds

Hemp oil is oil obtained by pressing hemp seeds. Cold pressed, unrefined hemp oil is dark to clear light green in color, with a nutty flavor. The darker the color, the grassier the flavour. It should not be confused with hash oil, a tetrahydrocannabinol-containing oil made from the Cannabis flower.

<span class="mw-page-title-main">Grape seed oil</span> Liquid fat derived from grape seeds

Grape seed oil is a vegetable oil derived from the seeds of grapes. Grape seeds are a winemaking by-product, and oil made from the seeds is commonly used as an edible oil.

<span class="mw-page-title-main">Cottonseed oil</span> Cooking oil

Cottonseed oil is cooking oil from the seeds of cotton plants of various species, mainly Gossypium hirsutum and Gossypium herbaceum, that are grown for cotton fiber, animal feed, and oil.

<span class="mw-page-title-main">Drying oil</span> Oil that hardens after exposure to air

A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components crosslink by the action of oxygen. Drying oils are a key component of oil paint and some varnishes. Some commonly used drying oils include linseed oil, tung oil, poppy seed oil, perilla oil, and walnut oil. Their use has declined over the past several decades, as they have been replaced by alkyd resins and other binders.

Linoleic acid (LA) is an organic compound with the formula HOOC(CH2)7CH=CHCH2CH=CH(CH2)4CH3. Both alkene groups are cis. It is a fatty acid sometimes denoted 18:2 (n-6) or 18:2 cis-9,12. A linoleate is a salt or ester of this acid.

<span class="mw-page-title-main">Sesame oil</span> Edible oil from sesame seed

Sesame oil is an edible vegetable oil derived from sesame seeds. The oil is one of the earliest-known crop-based oils. Worldwide mass modern production is limited due to the inefficient manual harvesting process required to extract the oil. Oil made from raw seeds, which may or may not be cold-pressed, is used as a cooking oil. Oil made from toasted seeds is used for its distinctive nutty aroma and taste, although it may be unsuitable for frying, which makes it taste burnt and bitter.

<span class="mw-page-title-main">Corn oil</span> Oil from the seeds of corn

Corn oil or maize oil (British) is oil extracted from the germ of corn (maize). Its main use is in cooking, where its high smoke point makes refined corn oil a valuable frying oil. It is also a key ingredient in some margarines. Corn oil is generally less expensive than most other types of vegetable oils.

The smoke point, also referred to as the burning point, is the temperature at which an oil or fat begins to produce a continuous bluish smoke that becomes clearly visible, dependent upon specific and defined conditions. Smoke point values can vary greatly, depending on factors such as the volume of oil utilized, the size of the container, the presence of air currents, the type and source of light as well as the quality of the oil and its acidity content, otherwise known as free fatty acid (FFA) content. The more FFA an oil contains, the quicker it will break down and start smoking. The lower the value of FFA, the higher the smoke point. However, the FFA content typically represents less than 1% of the total oil and consequently renders smoke point a poor indicator of the capacity of a fat or oil to withstand heat.

<span class="mw-page-title-main">Soybean oil</span> Oil obtained from seeds of soya plant

Soybean oil is a vegetable oil extracted from the seeds of the soybean. It is one of the most widely consumed cooking oils and the second most consumed vegetable oil. As a drying oil, processed soybean oil is also used as a base for printing inks and oil paints.

<span class="mw-page-title-main">Sunflower oil</span> Oil pressed from the seed of Helianthus annuus

Sunflower oil is the non-volatile oil pressed from the seeds of the sunflower. Sunflower oil is commonly used in food as a frying oil, and in cosmetic formulations as an emollient.

<span class="mw-page-title-main">Polyunsaturated fat</span> Type of fatty acid defined by molecular bonds

In biochemistry and nutrition, a polyunsaturated fat is a fat that contains a polyunsaturated fatty acid, which is a subclass of fatty acid characterized by a backbone with two or more carbon–carbon double bonds. Some polyunsaturated fatty acids are essentials. Polyunsaturated fatty acids are precursors to and are derived from polyunsaturated fats, which include drying oils.

<span class="mw-page-title-main">Pecan oil</span>

Pecan oil is an edible pressed oil extracted from the pecan nut. Pecan oil is neutral in flavor and takes on the flavor of whatever seasoning is being used with it. Pecan oil contains 9.5% saturated fat, which is less than in olive oil (13.5%), peanut oil (16.90%) or corn oil (12.70%). It is also used as a massage oil and in aromatherapy applications.

<span class="mw-page-title-main">Pistachio oil</span> Oil pressed from pistachio nuts

Pistachio oil is a pressed oil, extracted from the fruit of Pistacia vera, the pistachio nut.

<span class="mw-page-title-main">Cooking oil</span> Oil consumed by humans, of vegetable or animal origin

Cooking oil is a plant or animal liquid fat used in frying, baking, and other types of cooking. Oil allows higher cooking temperatures than water, making cooking faster and more flavorful, while likewise distributing heat, reducing burning and uneven cooking. It sometimes imparts its own flavor. Cooking oil is also used in food preparation and flavoring not involving heat, such as salad dressings and bread dips.

References

  1. 1 2 "National Nutrient Database for Standard Reference, Release 28". USDA National Nutrient Database. 2017. Retrieved 3 November 2017.
  2. 1 2 Ojeda-Amador, Rosa M.; Salvador, María Desamparados; Gómez-Alonso, Sergio; Fregapane, Giuseppe (2018). "Characterization of virgin walnut oils and their residual cakes produced from different varieties". Food Research International. 108: 396–404. doi:10.1016/j.foodres.2018.03.066.
  3. Bodoira, Romina; Maestri, Damián (2020). "Phenolic Compounds from Nuts: Extraction, Chemical Profiles, and Bioactivity". Journal of Agricultural and Food Chemistry. 68 (4): 927–942. doi:10.1021/acs.jafc.9b07160. PMID   31910006.
  4. 1 2 Ben-Erik van Wyk (2014). Culinary Herbs and Spices of the World. University of Chicago Press. p. 154. ISBN   9780226091839.
  5. "Walnut industry". California Walnuts. 2017.
  6. Ulrich Poth (2002). "Drying Oils and Related Products". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a09_055. ISBN   978-3527306732.
  7. Schimek, Erik (2010-03-19). "Finishing with Walnut Oil and Beeswax". Erik Organic. Archived from the original on 2011-05-08. Retrieved 2011-11-10.