Effect of storage and processing of Brazilian flaxseed on lipid and lignan contents

Abstract

<jats:p>Flaxseed has been widely studied around the world; its incorporation into products habitually consumed by human populations has been stimulated due to its unique nutritional value. The objective of this study was to evaluate the chemical composition of Brazilian flaxseed, to analyze the stability of lipids present in whole flaxseed flour (WFF) or partially defatted flaxseed flour (DFF) stored under several temperatures, and to investigate the effect of bread making on a product containing flaxseed. Whole flaxseed flour presented (g.100 g-1) 25.7 of insoluble fiber, 10.7 of soluble fiber, 38.9 of lipids, and 2.65 of lignan. Defatted flaxseed flour presented 65% less lipids, 36% more fiber and 56% more lignan than whole flaxseed flour. The fatty acid profile was maintained in the defatted flaxseed flour, and it presented a stable composition during storage under ambient temperature, refrigeration, and freezing. The fatty acid profile was similar in the bread containing defatted flaxseed flour after dough development, baking, and storage at room temperature or refrigerated. After baking, 89% of the lignan content was kept in bread. Results show that Brazilian flaxseed has an interesting chemical composition, and that defatted flaxseed, by-product of lipid extraction, presents a good stability to grind and storage under several temperatures. Thus, defatted flaxseed flour can be incorporated in bread, increasing its nutritional and functional value.</jats:p>

Stability of bioactives in flaxseed and flaxseed-fortified foods

“…The heat tolerance of SDG was further confirmed as no significant changes in SDG were observed in baked breads compared to the starting doughs that were prepared with purified SDG extracted from ground flaxseed meal (GFM) (Hyvarinen et al, 2006a). The heat stability of SDG has been further emphasized in a number of studies involving baked goods at temperatures ranging from 160°C to 225°C (Hyvarinen et al, 2006a;Simbalista et al, 2012), in MFX-fortified pasta at drying temperatures of 40°C, 70°C and 90°C and in dairy products (treatment of raw milk, 85°C and fermentation, 43°C for 5 h) (Hyvarinen et al, 2006b). In all of the above-mentioned studies, flaxseed was either milled or present as SDG prior to baking (Table 4) indicating the high tolerability of SDG towards standard baking temperatures.…”

“…In another study, SDG powder extracted from ground flaxseed meal had a small and insignificant decline following the leavening process in buns (Hyvarinen et al, 2006a). Simbalista et al further demonstrated that on both a dry and wet basis, bread dough made with defatted flaxseed flour had significant decreases in SDG content following dough development strongly suggesting that fermentation reduced the amount of SDG (Simbalista et al, 2012). Based on evidence from these combined studies, fermentation does appear to influence SDG recovery, requiring further evaluation of the individual and combined impacts of different yeast strains, flaxseed form and fermentation temperatures on final SDG content.…”

“…Oxidative degradation was minimal when compared to control muffins as assessed by MDA (Cunnane et al, 1993) and TBARS (Cunnane et al, 1995), yet oxygen consumption increased in a MFX muffin mix relative to a control mix suggesting the potential for oxidation (Chen et al, 1994). ALA in breads made with MFX appeared stable after storage under several conditions (Simbalista et al, 2012). Bread prepared with defatted flaxseed flour had stable fatty acid and ALA composition when stored in polyester and polyethylene golden-foiled bags at RT or 5°C when compared after 7 days of storage (Simbalista et al, 2012).…”

“…The oxidative stability of defatted flaxseed (DFX) was also examined (Simbalista, Frota, Soares, and Arêas, 2012). Following storage for 14 days at either RT, 5°C or − 12°C in polyester and polyethylene golden-foiled bags, samples exhibited the greatest oxidative damage at RT after 14 days.…”

“…ALA in breads made with MFX appeared stable after storage under several conditions (Simbalista et al, 2012). Bread prepared with defatted flaxseed flour had stable fatty acid and ALA composition when stored in polyester and polyethylene golden-foiled bags at RT or 5°C when compared after 7 days of storage (Simbalista et al, 2012). Unfortunately, it is unknown if the bags were sealed or open to atmospheric conditions as this may influence ALA stability.…”