Characteristics of flaxseed hull oil

Oils from two commercial flaxseed hulls extracted by six procedures were evaluated for physicochemical characteristics. oil yield ranged from 9% to 28% depending on solvent and extraction. Lipid fractionation of crude flaxseed hull oil yielded 92.5% neutral lipids, 3.1% phospholipids. 2.4% acidic lipids and 2.1% free. fatty acids. Flaxseed hull oil exhibited three thermal transitions between -35 and -13 degrees C with solvent dependent polymorphism. Thermal oxidation by differential scanning calorimetry (DSC) revealed three step oxidation of flaxseed hull Oil with mean onset and oxidation temperatures at 121 and 150253 degrees C, respectively depending on the extraction procedure. Flaxseed hull oil exhibited two-fold difference (0.6-1.2 mu m Trolox equivalent/g) in antioxidant activity measured by a photochemiluminescence (PCL) assay. Supercritical CO2 extracted the most oil with the highest antioxidant capacity of all evaluated procedures resulting in a defatted flaxseed hull containing the highest (53 mg/g) secoisolariciresinol diglucoside (SDG) level. (c) 2008 B. D. Oomah and L. Sitter of the department of Agriculture and Food, Government of Canada. Published by Elsevier Ltd. All rights reserved.