Antioxidant activity of flaxseed meal components

The meals of borage, hemp, Solin, golden, and brown flaxseed, including the meals of dehulled flaxseed and their corresponding hulls, were reconstituted with 40% of standard flaxseed oil and stored for 2 wk to assess if these meals had any antioxidant activity to protect in situ oil from oxidation. Weekly measured peroxide and aldehyde values showed that Solin, golden and brown flaxseed meals had more effective antioxidant activity than hemp and borage meals. Flaxseed hull showed very weak antioxidant potential, whereas dehulled meals maintained their antioxidant activity. This suggested that secoisolariciresinol diglucoside was not acting as the primary antioxidant of flaxseed meal. The seed antioxidant activity was greatly affected by water extraction, suggesting that the system contains water-soluble components. When flaxseed oil was recombined with the freeze-dried water extracts of flaxseed meal some loses of antioxidant activity were observed. The results showed that the water-extracted components retained some antioxidant activity compared with the original flaxseed meal antioxidant activity. These results indicate that the flaxseed antioxidant activities were mainly due to a water-soluble system - probably proteins: however, more than one group of components of the flax meal may be involved to provide the seed with its effective and unique antioxidant properties.