Simultaneous extraction of oil and antinutritional compounds from flaxseed

A two‐phase solvent extraction process, developed in our laboratory for rapeseed, was used to simultaneously extract oil and toxic, antinutritional components from flaxseed to produce a meal suitable for animal feed. The most effective solvent systems consisted of hexane in combination with a solution of methanol that contained 10% (vol/vol) water and 2.5–5% (w/w) ammonia, or methanol that contained 10% water (vol/vol) and 0.08% (w/w) NaOH. The treatments were carried out both at laboratory and semipilot‐plant scales. The success of the test with a pilot‐scale Karr liquid‐liquid extraction column suggested that this process could be readily carried out on an industrial scale. The resulting flax meal had a high protein content (40–47%) and low levels of cyanogenic glycosides (reduced by 90–100% from the starting material). The methanol‐ammonia extraction reduced the total polyphenol content by ≈20%. The oil extraction efficiency of the Karr column was high, resulting in meal residual oil contents of ≈1%.