A wet-screening strategy for flaxseed dehulling and compositional quantification of the separated fractions

A facile strategy for dehulling of six Canadian flaxseed cultivars using ethanol wash in combination with wet-screening was reported. Quantitative determinations of nutritional components including oil, sterol, protein, carbon and cyclolinopide in each separated fraction were also performed. Results showed that an efficient separation of hull, kernel and oil from the whole seed is achieved, because ethanol wash can eliminate the stubborn interference of flaxseed oil, thus facilitating the shell and kernel separation procedure. Among six flaxseed cultivars, the separated hull, kernel and oil account for 20.52-26.66%, 36.02-43.23% and 29.82-32.00% of whole seed, respectively. Triglyceride and sterol contents in separated hull, kernel, oil, whole seed are 2.13-3.34%, 24.68-27.46%, 97.26-98.84%, 37.70-45.82% and 0.02-0.11%, 0.04-0.08%, 0.28-0.53%, 0.11-0.23%, respectively. Besides, flaxseed oil is rich in cyclolinopepides, including new orbitides Q, R and S that have never been reported in these flaxseed varieties. Protein and carbon contents in separated hull, kernel and whole seed are 19.01-26.46%, 34.91-43.80%, 20.15-24.65% and 55.39-56.59%, 45.11-45.93%, 49.61-50.94%, respectively. In addition, the milled flaxseed hull shows a concentration-dependent intrinsic viscosity. This study presents a convenient method for flaxseed dehulling and preliminarily reveals the distribution of different nutrient elements in different parts of flaxseed.