methionine is attributed to improved antioxidant ability, thus reducing the risk of
cancer (Oomah 2001).
10.4.3 Carbohydrates and Dietary Fiber
Flaxseed contains very low level of carbohydrate (1 g/100 g) and thus contributes
very less in total carbohydrate intake (Morris 2007a). Flaxseed contains high amount
of dietary fiber, both soluble (9%) and insoluble (20%) fiber whose proportions vary
in the range between 20:80 and 40:60 (Morris 2003; Cui 2001; Hadley et al. 1992).
Cellulose and lignin form the insoluble fraction, while mucilage gums form the part
of soluble fraction of flaxseed dietary fiber (Vaisey-Genser and Morris 2003). The
soluble fiber portion is majorly present in the seed coat. Soluble fiber can be easily
extracted with hot water (Cui et al. 1994) than cold water (Paynel et al. 2013). Acidic
polysaccharides (L-rhamnose, L-galactose, L-fructose, and D-xylose) and neutral
polysaccharides (L-arabinose and D-xylose/D-galactose) are the major components
of soluble fiber (Anderson and Lowe 1947). Insoluble fiber contains cellulose,
lignin, and acid detergent fiber, whereas the mucilage arabinogalactans are associated with protein (Cui et al. 1994; Ray et al. 2013). Insoluble fiber acts as laxative
and helps in reduction of constipation (Greenwald et al. 2001), whereas soluble fiber
helps in maintenance of blood glucose and blood cholesterol level (Kristensen et al.
2012).
10.4.4 Polyphenols and Lignan
Phenolic compounds are known for their anticancer and antioxidative properties.
Phenolic acids, flavonoids, and lignans are the three major phenolic compound
groups present in flaxseed. Ferulic acid, chlorogenic acid, and gallic acid are major
phenolic acids present in defatted flaxseed, while p-Coumaric acid glucosides,
hydroxycinnamic acid glucosides, and 4-hydroxybenzoic acid are present in minor
quantities (Beejmohun et al. 2007; Mazza 2008). Flavone C and flavone
O-glycosides are the major flavonoids present in flaxseed (Mazza 2008). Lignans
can act as both antioxidants and phytoestrogens. Secoisolariciresinol diglucoside
(SDG), matairesinol, lariciresinol, and pinoresinol are the major lignan compounds
present in flaxseed (Tourre and Xueming 2010; Milder et al. 2005). The amount of
SDG varies in defatted flaxseed flour (11.7–24.1 mg/g) and whole flaxseed
(6.1–13.3 mg/g) (Johnsson et al. 2000). The SDG found in flax can provide
antioxidant effects (Adlercreutz 2007) and can be helpful in controlling cancerous
tumor growth (Tham et al. 1998).
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257
cancer (Oomah 2001).
10.4.3 Carbohydrates and Dietary Fiber
Flaxseed contains very low level of carbohydrate (1 g/100 g) and thus contributes
very less in total carbohydrate intake (Morris 2007a). Flaxseed contains high amount
of dietary fiber, both soluble (9%) and insoluble (20%) fiber whose proportions vary
in the range between 20:80 and 40:60 (Morris 2003; Cui 2001; Hadley et al. 1992).
Cellulose and lignin form the insoluble fraction, while mucilage gums form the part
of soluble fraction of flaxseed dietary fiber (Vaisey-Genser and Morris 2003). The
soluble fiber portion is majorly present in the seed coat. Soluble fiber can be easily
extracted with hot water (Cui et al. 1994) than cold water (Paynel et al. 2013). Acidic
polysaccharides (L-rhamnose, L-galactose, L-fructose, and D-xylose) and neutral
polysaccharides (L-arabinose and D-xylose/D-galactose) are the major components
of soluble fiber (Anderson and Lowe 1947). Insoluble fiber contains cellulose,
lignin, and acid detergent fiber, whereas the mucilage arabinogalactans are associated with protein (Cui et al. 1994; Ray et al. 2013). Insoluble fiber acts as laxative
and helps in reduction of constipation (Greenwald et al. 2001), whereas soluble fiber
helps in maintenance of blood glucose and blood cholesterol level (Kristensen et al.
2012).
10.4.4 Polyphenols and Lignan
Phenolic compounds are known for their anticancer and antioxidative properties.
Phenolic acids, flavonoids, and lignans are the three major phenolic compound
groups present in flaxseed. Ferulic acid, chlorogenic acid, and gallic acid are major
phenolic acids present in defatted flaxseed, while p-Coumaric acid glucosides,
hydroxycinnamic acid glucosides, and 4-hydroxybenzoic acid are present in minor
quantities (Beejmohun et al. 2007; Mazza 2008). Flavone C and flavone
O-glycosides are the major flavonoids present in flaxseed (Mazza 2008). Lignans
can act as both antioxidants and phytoestrogens. Secoisolariciresinol diglucoside
(SDG), matairesinol, lariciresinol, and pinoresinol are the major lignan compounds
present in flaxseed (Tourre and Xueming 2010; Milder et al. 2005). The amount of
SDG varies in defatted flaxseed flour (11.7–24.1 mg/g) and whole flaxseed
(6.1–13.3 mg/g) (Johnsson et al. 2000). The SDG found in flax can provide
antioxidant effects (Adlercreutz 2007) and can be helpful in controlling cancerous
tumor growth (Tham et al. 1998).
10 Flaxseed (Linum usitatissimum)
257