Tree Nut Oils

Abstract

Tree nut oils are primarily composed of triacylglycerols, but also contain diacylglycerols, monoacylglycerols, free fatty acids, and other minor components, including natural antioxidants and fat-soluble vitamins. The chemical composition of edible fats and oils largely determines their stability, quality, nutritional value, sensory properties, and potential health effects. Tree nuts, in many cases, provide rich sources of food lipids; up to 75% lipid on a weight basis. With a few exceptions, tree nut lipids exist as oils at room temperature. Generally, tree nuts are rich in monounsaturated fatty acids, predominantly oleic acid, but contain much lower amounts of polyunsaturated fatty acids, predominantly linoleic acid and small amounts of saturated lipids. In many parts of the world, such as the Middle East and Asia, tree nuts are cultivated for use as oil crops and are important sources of energy and essential dietary nutrients as well as phytochemicals. Tree nut oils are also used as components of some skin moisturizers and cosmetic products. 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. Recent investigations have also shown that dietary consumption of tree nut oils may exert even more beneficial effects than consumption of whole tree nuts, possibly due to the replacement of dietary carbohydrate with unsaturated lipids or other components present in the oil extracts. Tree nut byproducts are used as sources of dietary protein and as health-promoting phytochemicals such as natural antioxidants. This chapter summarizes the characteristics and potential health effects of several tree nut oils and their byproducts, including almond oil, hazelnut oil, pecan oil, walnut oil, pistachio oil, Brazil nut oil, pine nut oil, and macadamia nut oil, among others. Protein compositions of tree nut byproducts are also discussed collectively at the end of this chapter, with emphasis on the completeness of these proteins based on their amino acid compositions. Keywords: tree nuts; almond; hazelnut; oils; pecan; walnut; pistachio; fatty acid; brazil nut; pine nut; macadamia; cashews nut; meals; protein source