glycosides release poisonous hydrogen cyanide, a potential respiratory inhibitor
(Tanwar et al. 2018). Hydrogen cyanide can be converted to thiocyanates by
intestinal β-glycosidase which can interfere with iodine uptake and in chronic
cases may lead to iodine deficiency disorders, goiter, and cretinism. Several thermal
and nonthermal processing techniques such as autoclaving, microwave roasting,
pelleting, and soaking in saline water and enzymatic treatments by detoxifying
enzymes such as β-glycosidases may destroy cyanogenic glycosides (Feng et al.
2003; Yamashita et al. 2007; Tanwar et al. 2018).
Another important antinutrient present in flaxseed is phytic acid (23–33 g/kg of
flaxseed meal) (Oomah et al. 1996a, b). Phytic acid, a strong chelator, reduces the
bioavailability of minerals and interferes with the absorption of several important
minerals (Akande et al. 2010). Flaxseed antinutrients have lesser impact on human
health as compared to that of soybean and canola (Ganorkar and Jain 2013).
Flaxseed contains linatine (antipyrodoxidine factor) (10 mg/100 g) and may induce
vitamin B 6 deficiency (Mazza 2008). Flaxseed also contains trypsin inhibitors, but
their activity has been found to be not significant (Bhatty 1993).
10.5 Bioactive Compounds of Flaxseed
Linolenic acid, linoleic acid, lignans, cyclic peptides, etc. are the important bioactive
compounds present in flaxseed (Shim et al. 2014). Flaxseed oil contains bioactive
peptides that oxidize during the initial storage period (Bruhl et al. 2007).
Secoisolariciresinol diglucoside (SDG), a precursor of phytoestrogen also has phytochemical and antioxidant properties (Prasad 2004). Flaxseed lignan complex, an
oil-insoluble alcoholic extract of flaxseed containing SDG, phenylpropanoids, and
hydroxymethyl glutaric acid, is reported to have multiple physiological effects in
animals and humans (Shim et al. 2014).
Flaxseed proteins, rich in arginine, are associated with lower level of blood
pressure (Udenigwe et al. 2012). It is reported that when hypertensive rats (SHR)
were fed flaxseed protein isolates (FPI) (200 mg/kg bw), effectively lowered blood
pressure was observed (Shim et al. 2014). Flaxseed proteins digested with
flavourzyme-generated ACE inhibitory peptides having hydroxyl radicals scavenging activity (Marambe et al. 2008). Flaxseed proteins hydrolyzed either by
thermolysin and pronase (Udenigwe and Aluko 2010) or alcalase (Omoni and
Aluko 2006) yielded biologically active peptides that have ACE inhibitory
properties.
Gorski et al. (2001) have established important biological activity of
cyclolinopeptides isolated from flaxseed oil such as immunosuppressive activities
in mice and downregulation of cholesterol levels in rats. However, limited data is
available regarding the release of such peptides under gut conditions (Marambe et al.
2011).
10 Flaxseed (Linum usitatissimum)
259
(Tanwar et al. 2018). Hydrogen cyanide can be converted to thiocyanates by
intestinal β-glycosidase which can interfere with iodine uptake and in chronic
cases may lead to iodine deficiency disorders, goiter, and cretinism. Several thermal
and nonthermal processing techniques such as autoclaving, microwave roasting,
pelleting, and soaking in saline water and enzymatic treatments by detoxifying
enzymes such as β-glycosidases may destroy cyanogenic glycosides (Feng et al.
2003; Yamashita et al. 2007; Tanwar et al. 2018).
Another important antinutrient present in flaxseed is phytic acid (23–33 g/kg of
flaxseed meal) (Oomah et al. 1996a, b). Phytic acid, a strong chelator, reduces the
bioavailability of minerals and interferes with the absorption of several important
minerals (Akande et al. 2010). Flaxseed antinutrients have lesser impact on human
health as compared to that of soybean and canola (Ganorkar and Jain 2013).
Flaxseed contains linatine (antipyrodoxidine factor) (10 mg/100 g) and may induce
vitamin B 6 deficiency (Mazza 2008). Flaxseed also contains trypsin inhibitors, but
their activity has been found to be not significant (Bhatty 1993).
10.5 Bioactive Compounds of Flaxseed
Linolenic acid, linoleic acid, lignans, cyclic peptides, etc. are the important bioactive
compounds present in flaxseed (Shim et al. 2014). Flaxseed oil contains bioactive
peptides that oxidize during the initial storage period (Bruhl et al. 2007).
Secoisolariciresinol diglucoside (SDG), a precursor of phytoestrogen also has phytochemical and antioxidant properties (Prasad 2004). Flaxseed lignan complex, an
oil-insoluble alcoholic extract of flaxseed containing SDG, phenylpropanoids, and
hydroxymethyl glutaric acid, is reported to have multiple physiological effects in
animals and humans (Shim et al. 2014).
Flaxseed proteins, rich in arginine, are associated with lower level of blood
pressure (Udenigwe et al. 2012). It is reported that when hypertensive rats (SHR)
were fed flaxseed protein isolates (FPI) (200 mg/kg bw), effectively lowered blood
pressure was observed (Shim et al. 2014). Flaxseed proteins digested with
flavourzyme-generated ACE inhibitory peptides having hydroxyl radicals scavenging activity (Marambe et al. 2008). Flaxseed proteins hydrolyzed either by
thermolysin and pronase (Udenigwe and Aluko 2010) or alcalase (Omoni and
Aluko 2006) yielded biologically active peptides that have ACE inhibitory
properties.
Gorski et al. (2001) have established important biological activity of
cyclolinopeptides isolated from flaxseed oil such as immunosuppressive activities
in mice and downregulation of cholesterol levels in rats. However, limited data is
available regarding the release of such peptides under gut conditions (Marambe et al.
2011).
10 Flaxseed (Linum usitatissimum)
259