Characterization of a Partially Purified Extract from Flax (Linum usitatissimum L.) Seed

A water-soluble partially purified extract from defatted flax seed was obtained and characterized; it contained proteins (828.8 g/Kg), as well as water-soluble carbohydrates (101.4 g/Kg) and phenolic compounds (22.2 g/Kg), essentially secoisolariciresinol diglucoside (SDG, 18.40 g/Kg) and ferulic acid (1.45 g/Kg) and p-coumaric acid (2.07 mg/kg) mainly in their glycoside forms. Proteins of 23-24 kDa were the main protein fractions found in the extract. In an emulsion model system, the flax extract was able to inhibit the production of oxidation products (conjugated diene, peroxides and aldehydes) as well as the degradation of flax oil carotenoids. The antioxidant effects of the flax extract were concentration dependent. Oxidation kinetics of the emulsion supplemented with 0.10 % flax extract were similar to the oxidation kinetics of the control blank, whereas, oxidation parameters of the emulsion supplemented with 0.48 % (and higher) flax extract were equal to or better than the oxidation parameters obtained with the test control emulsion containing 0.01 % BHT. These results suggested that flax seed phenolic compounds (SDG) and low molecular weight proteins, both found in the studied extract, might have very strong antioxidant properties. This is paper number 1089 of the Canadian Grain Commission.