Walnut oil

Wagner equation Wagner number Wakamatsu reaction Waldhof fermentor Walkman Wallace plasticity Wallach procedure Wall baffles Wallboard Wall geometries Wallpaper paste Wallpaper pastes Wallpapers Wall plaster Walnut oil... 

A considerable quantity of oil can be extracted from waste material from shelling and processing plants, eg, the inedible kernels rejected during shelling and fragments of kernels recovered from shells. About 300 t of pecan oil and 300—600 t of English walnut oil are produced aimuaHy from such sources. The oil is refined and used for edible purposes or for the production of soap the cake is used in animal feeds (see Feeds and feed additives). Fmit-pit oils, which closely resemble and are often substituted for almond oil, are produced on a large scale for cosmetic and pharmaceutical purposes (143). For instance, leaves, bark, and pericarp of walnut may be used to manufacture vitamin C, medicines, dyes and tannin materials (144). 

Nuss-griesskohle, /., -gnis, m. nutty slack, -kem, m. nut kernel, -kemmehl, n. nut meal, -kohle, /. nut coal, -kormrng, /. nut size, -ol, n. nut oil specif., walnut oil. 

The ratio of palmitic acid to stearic acid (P/S) can be used to differentiate between drying oils, since these two saturated monocarboxylic acids are less subject to chemical reactions during treatment and ageing. Also, they have a similar chemical reactivity, so their ratio can be hypothesized to be relatively unaltered during ageing. The P/S ratio approach was pioneered by Mills [10], and has been subsequently adopted in a number of studies [7 9]. Typical values of the P/S ratio are 1 2 for linseed oil, 2 3 for walnut oil, 3 8 for poppy seed oil and 2.5 3.5 for egg. 

Evaluating the P/S ratio requires particular care first, because of the presence of mixtures of more than one binder, such as egg and oil in tempera grassa secondly, due to the presence of waxes, and in particular beeswax, which has been widely used as a coating and restoration material and thirdly, due to the contribution of FAs from other sources such as fouling or micro-organisms, which can considerably alter the P/S values from those expected for reference materials. For instance, because the ratio for walnut oil falls between the value of linseed oil, poppy oil and egg lipids, using the P/S ratio it is not possible to differentiate between pure walnut oil, and mixtures of linseed and poppy oil or egg. 

Oliveira R, Rodrigues MF and Bernardo-Gil MG. 2002. Characterization and supercritical carbon dioxide extraction of walnut oil. J Am Oil Chem Soc 79(3) 225-230. 

Wolff, R.L. (1993a) Occurrence of artificial trails polyunsaturated fatty acids in refined (deodorized) walnut oils. Sci. Aliment., 13, 155—163. 

Phytic acid (= Inositol soya bean, sunflower, walnut oil Widespread e.g. Poaceae [seed] AO... 

You may hear about getting omega-3s from plant sources, especially flaxseed and flaxseed oil but also from soybeans, canola and walnut oils, and various kinds of nuts. All of those foods contain a far less potent form of the beneficial fatty acids called alpha-linolenic acid (ALA). You may even see ALA supplements on sale in health food stores and pharmacies, but only a fraction, a small fraction, of ALA is converted by the body into EPA and DHA. Stick with the fish oils or the concentrated ethyl ester supplements. 

Walnut (Juglans regia). Walnut oil is an unsaturated oil containing both linoleic (50-60%) and linolenic acids (13-15%) and rich in tocopherols ( 1500 mg/kg of oil). It is used as a gourmet oil in Japan, France, and other countries. A recent paper gives the detailed composition (fatty acids, triacylglycerols sterols, and tocopherols) of oil extracted with hexane and with supercritical carbon dioxide (171). 

Walnuts contain about 65% lipids, however, considerable differences exist among varieties (range 52-70%, w/w) (1,40). Walnuts also contain 15.8% protein, 13.7% carbohydrate, 4.1% water, and 1.8% ash (w/w) (1). The fatty acid composition of walnut oil is unique compared with other tree nut oils for two reasons walnut oil contains predominantly linoleic acid (49-63%) and a considerable amount of ot-linolenic acid (8-15.5%). Other fatty acids present include oleic acid (13.8-26.1%), palmitic acid (6.7-8.7%), and stearic acid (1.4—2.5%) (Table 5) (40). The tocopherol content of walnut oil varies among different cultivars and extraction procedures and ranges between 268 mg/kg and 436 mg/kg. The predominant tocol isomer is y-tocopherol (>90%), followed by a-tocopherol (6%), and then (3- and 8-tocopherols (41). Nonpolar lipids have been shown to constitute 96.9% of total lipids in walnut oil, whereas polar lipids account for 3.1%. The polar lipid fraction consisted of 73.4% sphingolipids (ceramides and galactosylcera-mides) and 26.6% phospholipids (predominantly phosphatidylethanolamine) (42). Walnut oil contains approximately 1.8g/kg phytosterols (1), primarily p-sitosterol (85%), followed by A-5-avenasterol (7.3%), campesterol (4.6%), and, finally, cholesterol (1.1%) (42). 

Several research groups have investigated the oxidative stability of walnut oil and have shown that it is readily oxidizable. Demir and Cetin (36) investigated the oxidative stability of expeller-pressed and hexane-extracted walnut oil at... 

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