hormonal effects in both male and female rats (Tou et al. 1998), there are no
published evidences of safety issues in pregnant and lactating women and children.
The consumption of uncooked flaxseed could be toxic at higher doses due to the
presence of cyanogenic glycosides. Morris (2000) reported that intake of uncooked
flaxseed meal (more than 10 tablespoons/day) may increase the hydrogen cyanide
content to potentially toxic levels (>50–60 mg) among adults. Other reports indicated that consumption of baked flaxseed powder (50 g/day) does not increase
urinary thiocyanate levels (Cunnane et al. 1993a, b). Further, there is no report of
association of processed flaxseed consumption to that of chronic or acute cyanide
toxicity (Bloedon and Szapary 2004).
10.8 Food Applications
Before consumption, flaxseeds are processed by various processing methods, which
involve multiple steps that lead to extraction of oil and various by-products. Flaxseed
oil is known for its alpha-linolenic acid, which is a heat labile compound and
destroyed at high-temperature treatment (Choo et al. 2007) and is also prone to
autoxidation leading to quality deterioration. Hence, after cold extraction, it is
incorporated with antioxidants and stored in dark packaging materials to prevent
photo-induced deteriorative changes (Lukaszewicz et al. 2004). Flaxseed oil is
generally extracted by mechanical methods such as screw press extraction
(86–92% recovery) followed by sedimentation and filtration without any heat
treatment or refining (Wiesenborn et al. 2005). Freshly extracted (unrefined) oil
has a pleasant nutty flavor with attractive golden color. However, various
pre-treatments prior to pressing results in significant improvement in oil recovery
and quality. Solvent extraction using hexane at high temperatures yields high-quality
oil with maximum recovery (Nash and Frankel 1986). Bioactive alpha-linolenic acid
present in flaxseed oil can be degraded by exposure to high temperature; therefore,
emerging techniques such as supercritical fluid extraction technique, which involves
low-temperature processing (31
C) could be exploited. Reports are emerging with
regard to application of ultrasonic-assisted oil extraction techniques for speedy and
enhanced oil recovery with lesser solvent (Zhang et al. 2008).
10.8.1 Food Applications of Flaxseed
Although flaxseed is well-known since ancient times, the concept of utilizing
flaxseed in food formulations is comparatively recent. In the current functional
food regime, with an array of health benefits, flaxseed has emerged as a potential
functional ingredient. The nutritional and medicinal characteristics of flaxseed make
it a potential source of functional ingredients in the development of functional foods
(Rubilar et al. 2010). It can be utilized as a main food ingredient in order to enhance
10 Flaxseed (Linum usitatissimum)
269
published evidences of safety issues in pregnant and lactating women and children.
The consumption of uncooked flaxseed could be toxic at higher doses due to the
presence of cyanogenic glycosides. Morris (2000) reported that intake of uncooked
flaxseed meal (more than 10 tablespoons/day) may increase the hydrogen cyanide
content to potentially toxic levels (>50–60 mg) among adults. Other reports indicated that consumption of baked flaxseed powder (50 g/day) does not increase
urinary thiocyanate levels (Cunnane et al. 1993a, b). Further, there is no report of
association of processed flaxseed consumption to that of chronic or acute cyanide
toxicity (Bloedon and Szapary 2004).
10.8 Food Applications
Before consumption, flaxseeds are processed by various processing methods, which
involve multiple steps that lead to extraction of oil and various by-products. Flaxseed
oil is known for its alpha-linolenic acid, which is a heat labile compound and
destroyed at high-temperature treatment (Choo et al. 2007) and is also prone to
autoxidation leading to quality deterioration. Hence, after cold extraction, it is
incorporated with antioxidants and stored in dark packaging materials to prevent
photo-induced deteriorative changes (Lukaszewicz et al. 2004). Flaxseed oil is
generally extracted by mechanical methods such as screw press extraction
(86–92% recovery) followed by sedimentation and filtration without any heat
treatment or refining (Wiesenborn et al. 2005). Freshly extracted (unrefined) oil
has a pleasant nutty flavor with attractive golden color. However, various
pre-treatments prior to pressing results in significant improvement in oil recovery
and quality. Solvent extraction using hexane at high temperatures yields high-quality
oil with maximum recovery (Nash and Frankel 1986). Bioactive alpha-linolenic acid
present in flaxseed oil can be degraded by exposure to high temperature; therefore,
emerging techniques such as supercritical fluid extraction technique, which involves
low-temperature processing (31
C) could be exploited. Reports are emerging with
regard to application of ultrasonic-assisted oil extraction techniques for speedy and
enhanced oil recovery with lesser solvent (Zhang et al. 2008).
10.8.1 Food Applications of Flaxseed
Although flaxseed is well-known since ancient times, the concept of utilizing
flaxseed in food formulations is comparatively recent. In the current functional
food regime, with an array of health benefits, flaxseed has emerged as a potential
functional ingredient. The nutritional and medicinal characteristics of flaxseed make
it a potential source of functional ingredients in the development of functional foods
(Rubilar et al. 2010). It can be utilized as a main food ingredient in order to enhance
10 Flaxseed (Linum usitatissimum)
269