Flax seed oils

Amber to yellow oils obtained from flax-seed cotyledons (Linum usitatissimum). Hydraulic pressure extraction gives pale, bland oils; heat and pressure extraction gives darker oils with bitter flavour and off-odour. Rich in α-linolenic acid, they are used as food oils; also known as linseed oils. Cold-pressed food-grade oil is prized for its α-linolenic acid (ALA) content — over 50% of fatty acids — an essential omega-3, but it oxidises rapidly and must be refrigerated in dark bottles. Heat-extracted industrial linseed oil suits paints and varnishes, not food; food use demands low-temperature pressing and nitrogen blanketing.