Tree nut oils

The photochemiluminiscence (PCL) assay was initially used by Popov and others (1987). Popov and Lewin (1994 1996) have extensively studied this technique to determine water-soluble and lipid-soluble antioxidants. The PCL assay measures the antioxidant capacity, toward the 02 radical, in lipidic and water phase. This method allows the quantification of both the antioxidant capacity of hydrophilic and/or lipophilic substances, either as pure compounds or complex matrices from different origin synthetic, vegetable, animal, human, etc. The PCL method is based on an approximately 1,000-fold acceleration of the oxidative reactions in vitro by the presence of an appropriate photosensitizer. The PCL is a very quick and sensitive method. Chua and others (2008) used this assay to determine the antioxidant potential of Cin-namomum osmophloeum, whereas Kaneh and Wang and others (2006) determined the antioxidant capacity of marigold flowers. The antioxidant activity of tree nut oil extracts was also assessed by this method (Miraliakbari and Shahidi 2008). 

Miraliakbari H and Shahidi F. 2008. Antioxidant activity of minor components of tree nut oils. Food Chem 111 (2) 421—427. 

Beuchat, L.R. and Worthington, R.E. (1978) Fatty acid composition of tree nut oils. J. Food Technol.,... 

Miraliakbari, H. Shahidi, F. 2008. Oxidative stability of tree nut oils. J. Agric. Food Chem. 56 4751-4759. 

Homan Miraliakbari Memorial University of Newfoimdland, St. John s, Newfoundland, Canada, Tree Nut Oils. 

Flavor Components of Fats and Oils, Lipid Oxidation Measurement Methods, Marine Mammal Oils, Modification of Fats and Oils via Chemical and Enzymatic Methods, Novel Separation Techniques for Isolation and Purification of Fatty Acids and Oil By-Products, Quality Assurance of Fats and Oils, Tree Nut Oils. 

Tree nuts, tree nut oils, and tree nut byproducts (defatted meals and hulls) are known to contain several bioactive and health-promoting components. Epidemiological evidence indicates that the consumption of tree nuts may exert several cardioprotective effects, which are speculated to derive from their lipid component that includes unsaturated fatty acids, phytosterols, and tocols (4). Recent investigations... 

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). 

Pine nuts (pinon or pignolia) are the edible seeds within the pine cone of several varieties of pine trees (Pinus sp.) but most commonly Pinus pinea or stone pine . Pine nuts are harvested all over the world, most notably in Russia, China, North Korea, Spain, Italy, and Turkey, among others. Pine nuts contain 48-61% lipids by weight (1, 60). Other constiments of pine nut include carbohydrate (19.3%), protein (11.6%), water (5.9%), and ash (2.2%) (1). Pine nut oil contains predominantly linoleic acid (46.4%) and oleic acid (38.1%). Maritime pine nut Pinus pinaster) oil also contains two fatty acids that are unique among tree nut oils pinoleic acid and sciadonic acid (Figure 2), which exist at 7% each in pine nut oU and may have antiatherogenic effects (Table 8) (63). The phenolic acid composition of defatted pine nut meal is given in Table 2 and shows that caffeic acid is the predominant phenolic compound (14). 

With today s busy lifestyles, tree nuts are convenient, tasty, nutritious, and easy snack that contribute to a healthy lifestyle. They are typically consumed as whole nuts (either raw or roasted or salted) or used as ingredients in a variety of processed foods, especially in spreads, bakery, and confectionary products, among others. Tree nnt oils, in particular hazelnut oil, are also used for several purposes such as cooking, salad dressings, and flavoring ingredients, among others [3-6]. In addition, tree nut oils (particularly hazelnut oil) are also components of some skin moisturizers and cosmetic products [7]. 

Shahidi, F. and Miraliakhari, H., Tree nut oils and byproducts Compositional characteristics and nutra-ceutical applications, in Nutraceutical and Specialty Lipids and Their Co-Products, Shahidi, E, Ed., CRC Press, Taylor Francis Group, Boca Raton, FL, 2006, pp. 159-168. 

Miraliakhari, H. and Shahidi, R, Lipid class compositions, tocopherols and sterols of tree nut oils extracted with different solvents, J. Food Lipids, 15, 81-96, 2008. 

The oxidative stability of tree nut oils was examined under Schaal oven conditions at 60°C for 12 days (equivalent to 1 year storage at room temperature) [23]. The stability of the oils, as measured... 

The lipid classes of hazelnut oil include triacylglycerols (TAG) as nonpolar lipids (98.4%) and glucolipids (1.4%) and phosphoUpids (<0.2%) [phosphatidylcholine (PC) and phosphatidylinositol (PI)] as polar lipids [116]. The 18 lo)9 is dominant in the nonpolar lipid class (TAG), whereas 16 0, 18 0, and 18 2o)6 are most predominant in the polar Upid class in hazelnut oil. Recently, Alasalvar et al. [117] examined lipid class composition of Tombul hazelnut oil and found that it contained 98.8% of nonpolar and 1.2% of polar constituents. The main nonpolar lipid class in hazelnut oil is TAG, contributing nearly 100% to the total amount PC, phosphatidylethanolamine (PE), and PI are main polar Upids, contributing 56.4%, 30.8%, and 11.7% to the total polar lipids, respectively. Similar results were reported by Parcerisa et al. [105]. More recently, Miraliakbari and Shahidi [216] examined the lipid classes in tree nut oils that included TAG, sterols and sterol esters, phospholipids, and sphingoUpids. Hazelnut oil contained TAG, sterols, sterol esters, phosphatidylserine (PS), PC, PI, phosphatidic acid, and sphingoUpids. 

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