Flaxseed (Linum usitatissimum L.) has been the focus of interest of nutritionists due to potential health benefits.
Flaxseed is a rich source of different types of phenolics such as lignans, phenolic acids, flavonoids, phenylpropanoids and tannins.
Day by day, incorporation of flaxseed in food and in food products has been increasing due to its high content of essential omega-3 fatty acid, alpha-linolenic acid (ALA), dietary fiber and natural phenolic antioxidants
Antioxidants are synthetic or natural compounds that can delay some types of cell damage and quench reactive radical species formed during oxidative reactions in metabolism. They include mainly phenols, polyphenols, carotenoids, thocyanins and tocopherols, which main groups of phytochemicals found in plants.
Natural antioxidants have been associated with cancer development are generally opted by consumers because of their safety.
Most of the flaxseed phenolic acids such as p-hydroxybenzoic, trans-ferulic and trans-p-coumaric acids are ester bound. Among these phenolic acids, ferulic and p-coumaric acid glucosides were accumulated at high concentrations in the flaxseed. In addition, phenolic acid like caffeic acid and their glucosides were also reported in the flaxseed.
Caffeic acid is an organic compound that is classified as a hydroxycinnamic acid. It is found in all plants because it is a key intermediate in the biosynthesis of lignin, one of the principal components of woody plant biomass and its residues.
Flavonoids are the polyphenols, with C6-C3-C6 skeleton that consists of two aromatic rings joined by a three-carbon link. Flavonoids generally include anthocyanins, flavanols, flavones, flavanones and flavonols.
Depending upon growing and cultivar conditions, flaxseed possesses about 0.3-0.71 g of total flavonoids per kg of flaxseed. In the flaxseed, flavonoids are in the form of their glucoside such as herbacetin 3, 8-Odiglucopynanoside, herbacetin 3, 7 O-dimethyl ether, and kaempferol 3, 7-O-diglucopyranoside.
Antioxidants in flaxseed
