Sphingolipids in nuts

Fang, R, Ho, C.-T., Sang, S., and Rosen, R.T., Determination of sphingolipids in nuts and seeds by a single quadrupole liquid chromatography-mass spectrometry method, J. Food Lipids, 12, 327-343, 2005. 

Note represents the presence of the concerned sphingolipid in the respective nuts. 

Structure of sphingolipids in foods, especially foods of plant origin, is sparse. Recently, a developed LC/MS method with APCI positive ion mode has been nsed to separate, identify, and qnantify cer-amide and ceiebroside species simnltaneonsly in nnt samples inclnding almond, cashew, hazelnut, peanut, and walnnt. The ceiebroside consisting of 4,8-sphingadienine, a-hydroxypalmitic acid, and glucose as the head group was found to be the most abundant cerebroside in nuts. 

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). 

Cholesterol, Phytosterol Composition, and Sphingolipids (mg/IOOg) in Edible Tree Nuts... 

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