Storage stability of milled flaxseed

Trends and advances in pre- and post-harvest processing of linseed oil for quality food and health products

Linseed is an ancient crop used for diverse purposes since the beginning of civilization. In recent times, linseed has emerged as a superfood due to its high content of health-promoting omega-3 fatty acids and other bioactive compounds. Among primary health effects, it has potential to manage hypertension, diabetes, osteoporosis, atherosclerosis, cancer, arthritis, neurological, cardiovascular diseases including blood cholesterol levels, constipation, diarrhea, and autoimmune disorders etc. due to the presence of omega-3 fatty acid, lignans, high dietary fibers, and proteins, whereas, secondary health effects comprise of relieving from various skin disorders. Due to these health-beneficial properties, interest in linseed oil necessitates the intensification of research efforts on various aspects. These include cultivation technology, varietal and genetic improvement, post-harvest processing, profiling of nutrients and bioactive compounds, pre-clinical and clinical studies, etc. The present review discussed the advances in linseed research including pre- and post-harvest processing. However, focus on the bioactive compounds present in linseed oil and their health effects are also presented. Linseed cultivation, pre- and post-harvest processing aspects are covered including climatic, edaphic, agronomic factors, type of cultivar and storage conditions etc, which impact the overall oil yield and its nutritional quality. Various emerging applications of linseed oil in functional food, nutraceutical, pharmaceutical, and cosmeceutical preparations were also presented in detail. Further, recommendations were made on linseed oil research in the field of genetics, breeding germplasm resources and genome editing for exploring its full applications as a nutrition and health product.

DSC Phase Transition Profiles Analyzed by Control Charts to Determine Markers for the Authenticity and Deterioration of Flaxseed Oil during Storage

An approach of implementing X-bar and R control charts as a statistical control tool to monitor the changes in the melting profile of fresh and stored flaxseed oils by differential scanning calorimetry (DSC) was used. Phase transition melting profiles were collected after 0, 2, 4, and 6 months of storing flaxseed oils, originating from five different cultivars. Four peaks at around -36, -30, -25, and -12 °C were identified using the deconvolution analysis procedure, which enabled the data to be collected at peak temperature (T), peak height (h), the peak area (A), and the percentages of the area (P A), as well as the ratio calculated from these parameters. Control charts obtained for the second peak of the melting profile showed a significant decrease of peak height (h2) from 0.50 to 0.39 W/g and the percentage of the area (P A2) from 50 to 38%, within the storage time (p ≤ 0.05); thus, they were considered to be indicators of oil deterioration. Strong negative correlations of the unstable parameters of DSC with chemical indicators of the oils' oxidative stability (PV, p-AV, TOTOX) were found. For DSC parameters, related to the first peak (h1, A1) and the third peak (h3, A3), changes were statistically not significant within storage (p > 0.05); thus, they can be used as markers of flaxseed oil authenticity. The study demonstrated that X-bar and R control charts could effectively monitor changes in the specific peaks and calculated ratios from the DSC melting profile of fresh and stored flaxseed oils, serving as reliable indicators of oil deterioration.

A review of flaxseed lignan and the extraction and refinement of secoisolariciresinol diglucoside

Lignan is a class of diphenolic compounds that arise from the condensation of two phenylpropanoid moieties. Oilseed and cereal crops (e.g., flaxseed, sesame seed, wheat, barley, oats, rye, etc.) are major sources of plant lignan. Methods for commercial isolation of the lignan secoisolariciresinol diglucoside (SDG) are not well reported, as most publications describing the detection, extraction, and enrichment of SDG use methods that have not been optimized for commercial scale lignan recovery. Simply scaling up laboratory methods would require expensive infrastructure to achieve a marketable yield and reproducible product quality. Therefore, establishing standard protocols to produce SDG and its derivatives on an industrial scale is critical to decrease lignan cost and increase market opportunities. This review summarizes the human health benefits of flaxseed lignan consumption, lignan physicochemical properties, and mammalian lignan metabolism, and describes methods for detecting, extracting, and enriching flaxseed lignan. Refining and optimization of these methods could lead to the development of inexpensive lignan sources for application as an ingredient in medicines, dietary supplements, and other healthy ingredients.

Methods used for extraction of plant volatiles have potential to preserve truffle aroma: A review

Truffles are considered one of the world's most highly prized foods mainly due to their desirable organoleptic properties and rarity. However, truffles are seasonal (harvested mostly in winter from June to August in the Southern Hemisphere and from December to February in the Northern Hemisphere) and extremely perishable. Truffles deteriorate rapidly showing undesirable changes within 10 days from harvest in aroma and visual appearance after harvest. The very short postharvest shelf life (about 7-10 days) limits the potential for export and domestic consumption all year round. Several preservation methods have been studied to prolong their shelf life without the loss of aroma. However, all traditional preservation techniques have their own shortcomings and remain challenging. The extraction of natural truffle aroma volatiles for food applications could be a potential alternative to replace the existing synthetic flavoring used for processed truffle products. Four commonly used extraction methods for recovering volatile compounds from plants, namely, supercritical carbon dioxide extraction, Soxhlet extraction, distillation, and cold pressing, are critically analyzed. Up to date, existing research about the extraction of aroma volatiles from truffles is limited in the literature but based on the volatility of the key truffle volatile compounds, supercritical carbon dioxide extraction may offer the best possibility so that a natural truffle-based product that can be used in food applications throughout the year can be made available.

The Influence of Flaxseed Oil Cake Extract on Oxidative Stability of Microencapsulated Flaxseed Oil in Spray-Dried Powders

The objective of the study was to investigate the application of flaxseed oil cake extract (FOCE) for oxidative stabilization of flaxseed oil in spray-dried emulsions. Two variants of powders with 10% and 20% of flaxseed oil (FO), FOCE, and wall material (maltodextrin and starch Capsul^®) were produced by spray-drying process at 180 °C. The oxidative stability of FO was monitored during four weeks of storage at 4 °C by peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS) measurements. Additionally, the fatty acids content (especially changes in α-linolenic acid content), radical scavenging activity, total polyphenolics content, color changes and free amino acids content were evaluated. Obtained results indicated that FOCE could be an adequate antioxidant dedicated for spray-dried emulsions, especially with a high content of FO (20%). These results have important implications for the flaxseed oil encapsulation with natural antioxidant agents obtained from plant-based agro-industrial by product, meeting the goals of circular economy and the idea of zero waste.

Effects of xanthan gum, canning and storage period on fatty acid profile and cholesterol oxidation of restructured low-fat meat product of India

This study evaluated the impact of xanthan gum (XG), canning and storage on fatty acids (FAs) contents and formation of cholesterol oxidation products (COPs) in low-fat meat product (goshtaba) of Jammu and Kashmir (J&K), India. The FAs composition i.e. saturated FAs, monounsaturated FAs, polyunsaturated FAs and trans FAs during processing and storage showed non-significant difference in all goshtaba products (P > 0.05). The cholesterol content decreased significantly after canning in all products (P < 0.05) while, maximum reduction was observed in high-fat goshtaba (HFC). During storage all products exhibited significant decrease in cholesterol upto 6th month, thereafter showed non-significant variation. The COPs determined were 7-β-OH-ch, 5-ch-3β-ol-7-one and 25-OH-ch. After canning two COPs (7-β-OH-ch, 5-ch-3β-ol-7-one) were produced in all products. But during storage there was formation of 25-OH-ch, increase in 7-β-OH-ch and decrease in 5-ch-3β-ol-7-one and lower COPs were observed in low-fat goshtaba containing 1.5% XG. The results concluded that fat replacer (XG), processing and storage had no significant effect on the FAs compositions of all goshtaba products including HFC. However, cholesterol content exhibited significant variation and minimum reduction in cholesterol and formation of lower COPs were observed in low-fat goshtaba formulated with 1.5% XG.

Determination of 2,4-decadienal in edible oils using reversed-phase liquid chromatography and its application as an alternative indicator of lipid oxidation

As a major product of linoleic acid-rich oils, 2,4-decadienal has unique reactivity that may be potentially toxic to human body. In this study, a reliable reversed-phase liquid chromatography method for the determination of carbonyls was developed, and 2,4-decadienal as the target aldehyde was validated. Furthermore, the possibility of 2,4-decadienal as a lipid oxidation marker was evaluated. The optimal sample pretreatment method was extraction by 2 mL of acetonitrile three times, followed by derivatization at 40 °C for 30 min. The method was linear, sensitive, and accurate with detection and quantification limits of 15 and 50 nmol/L, respectively, and had good average recoveries for 2,4-decadienal in oil samples. In tested edible oils, during heating at 180 °C, the level of 2,4-decadienal rose faster than other aldehydes, including one of the characteristic aldehydes, hexanal. Moreover, good linear relationships between the 2,4-decadienal content and other oxidation indices (R² = 0.858 to 0.984 for the anisidine value; R² = 0.876 to 0.986 for the total oxidation value) were observed in sunflower and corn oils under 8 hr heating at three temperatures (120, 150, and 180 °C), indicating that 2,4-decadienal can predict the oxidation of oil. PRACTICAL APPLICATION: 2,4-Decadienal is a toxic aldehyde produced by the oxidation of linoleic acid-rich oils, which is closely related to human health. This work is the first to demonstrate that 2,4-decadienal can be used as an alternative oxidation indicator for linoleic acid-rich oils and is of great significance for the quality control of edible oil in the food industry.

Effect of infrared-assisted spouted bed drying of flaxseed on the quality characteristics of its oil extracted by different methods

BACKGROUND

Infrared (IR)-assisted spouted bed drying (SBD) has emerged as a potential alternative to the traditional hot air drying for heat sensitive components. The aim of this study was to investigate effect of IR-assisted SBD and application of cold press (CP), solvent extraction (SE) and ultrasound assisted extraction (UAE) on the quality of flaxseed oil. SBD and IR-assisted SBD were performed at air temperatures of 40, 60, 80 °C and their effects on the drying rate, fatty acids composition and oil peroxide and acid values were evaluated. Quality of oil extracted from the dried flaxseeds by CP, SE and UAE methods was then evaluated.

RESULTS

Increasing air temperature in the presence of IR increased the drying rate. The peroxide values (PVs) of IR-SBD samples were higher than those of SBD at the same temperature. IR treatment did not notably change the composition of fatty acids in flaxseed oil, except in linoleic acid content. UAE gave higher extraction yield than CP and SE methods. UAE yielded an oil with higher percentage of saturated fatty acids, whereas the percentage of omega-3 and omega-6 fatty acids was higher in the CP method. The oil extracted by CP exhibited lower levels of PV (0.516 meq O₂ /kg oil) and acid value (1.36%), as compared to oils extracted by SE and UAE methods.

CONCLUSION

Both UAE and conventional methods did not significantly influence the composition of fatty acids in the extracted oils. Nonetheless, the CP method yielded an oil with a high percentage of omega-3 and omega-6 fatty acids. © 2019 Society of Chemical Industry.

Dietary flaxseed: what we know and don't know about its effects on cardiovascular disease

Flaxseed (Linum usitatissimum) is composed of a unique combination of bioactive components that appear to generate, through either an isolated or a synergistic action, a significant beneficial effect on the cardiovascular system. With a significant increase in the generation of data on the dietary impact of flaxseed on the cardiovascular system, a review of where we stand - what we know and what we still need to understand about these effects on the heart and the vasculature - was thought to be of value and the rationale for this paper. For example, although we now know how to deliver the bioactives most efficiently (oil versus ground seed versus whole seed), we do not know how different foods can influence that delivery. Further, we know flaxseed has anti-arrhythmic, anti-atherogenic, anti-hypertensive, and cholesterol-lowering actions in animal studies and some selected human trials but much more needs to be learned, particularly in human trials. These results have justified further commitment of resources to the initiation of human trials. Because of the impact of nutrition on many chronic diseases, this may not only be true for the effects of flaxseed on cardiovascular disease but may be just as relevant for many other disease conditions.

Bread Enrichment with Oilseeds. A Review

The use of oilseeds in bakery products has gained popularity in recent years, both for their organoleptic and nutritional characteristics. The aim of this work is to provide an overview of the studies centered on the use of oilseeds (flaxseed, chia, sunflower, pumpkin, sesame and poppyseed) in breads and other bakery products. This review highlights the effect of oilseeds on the mechanical and physical properties of bread according to the enrichment level, origin and way of addition (whole, crushed, oil or mucilage). In general, the incorporation of oilseeds improves the nutritional profile of bakery products with and without gluten, and provides several health benefits. Mucilages of oilseeds can also act as a fat replacer thanks to their properties. The incorporation of oilseeds modifies the rheology of the doughs, the volume of the products and their texture, affecting their organoleptic characteristics and their acceptability. Nevertheless, these changes will depend on the type of seed used, as well as on the method of addition.

Ground flaxseed reverses protection of a reduced-fat diet against Citrobacter rodentium-induced colitis

Flaxseed is high in ω-3 polyunsaturated fatty acids, fiber, and lignans known to lower cholesterol levels. However, its use for prevention or treatment of inflammatory bowel diseases has yielded mixed results, perhaps related to dietary interactions. In this study, we evaluated the impact of ground flaxseed supplementation on the severity of Citrobacter rodentium-induced colitis in the setting of either a high-fat (HF, ~36%kcal) or reduced-fat (RF, ~12%kcal) diet. After weaning, C57BL/6 mice ( n = 8-15/treatment) were fed ground flaxseed (7 g/100 g diet) with either HF (HF Flx) or RF (RF Flx) diets for 4 wk before infection with C. rodentium or sham gavage. Weight changes, mucosal inflammation, pathogen burden, gut microbiota composition, tissue polyunsaturated fatty acids, and cecal short-chain fatty acids were compared over a 14-day infection period. The RF diet protected against C. rodentium-induced colitis, whereas the RF Flx diet increased pathogen burden, exacerbated gut inflammation, and promoted gut dysbiosis. When compared with the RF diet, both HF and HF Flx diets resulted in more severe pathology in response to C. rodentium infection. Our findings demonstrate that although an RF diet protected against C. rodentium-induced colitis and associated gut dysbiosis in mice, beneficial effects were diminished with ground flaxseed supplementation. NEW & NOTEWORTHY Our results demonstrate a strong protective effect of a reduced-fat diet against intestinal inflammation, dysbiosis, and pathogen burden during Citrobacter rodentium-induced colitis. However, ground flaxseed supplementation in the setting of a reduced-fat diet exacerbated colitis despite higher levels of intestinal n-3 polyunsaturated fatty acids and cecal short-chain fatty acids.

Microbial and Chemical Shelf-Life of Vacuum Steam-Pasteurized Whole Flaxseed and Milled Flaxseed

Flaxseed is an oilseed with many health benefits. Flaxseed may be consumed raw or in processed form. In the raw form, there is a potential for microbial contamination. Several pasteurization methods have been used to reduce microbial contamination. However, such treatments may affect chemical properties of foods. In this study, vacuum steam-pasteurization was conducted on whole flaxseed and milled flaxseed using 4 different conditions (3 min at 75 °C, 3 min at 90 °C, 9 min at 90 °C, and 3 min at 105 °C). Microbial and chemical shelf-life was monitored for 28 wk (36 wk for aerobic plate counts). Significant reduction (P < 0.05) in microbial counts (total aerobic plate counts, and yeast and mold counts) occurred after pasteurization and during storage of both whole flaxseed and milled flaxseed. Although both the moisture content and a_w increased after pasteurization, they were similar to the unpasteurized samples during storage. Peroxide value, free fatty acid, headspace volatiles, fatty acid profiles, oil content, and secoisolariciresinol diglucoside (SDG) content were chemical indices measured. Only small changes were observed in the chemical indices after vacuum steam-pasteurization for both pasteurized whole flaxseed and milled flaxseed as compared to the unpasteurized flaxseed at most instances. Vacuum steam-pasteurization can be used as a safe alternative for the microbial reduction of low-moisture products, such as flaxseed, without significantly affecting chemical stability.

PRACTICAL APPLICATION

Vacuum steam-pasteurization can be effectively used for the treatment of whole flaxseed and milled flaxseed to reduce spoilage microorganisms, such as total aerobes and yeasts and molds. In addition, this pasteurization method had minimal effects on several chemical shelf-life parameters with positive impact on SDG of the processed flaxseed.

Increasing meat product functionality by the addition of milled flaxseed Linum usitatissimum

BACKGROUND

Functional meat products are still rare on the market because it is difficult to incorporate new ingredients and obtain both a healthy and acceptable product. Flaxseed is known for its beneficial properties and, in the present study, it was used as an ingredient in the production of homogenised and liver sausages (0%, 5% and 10% flaxseed addition).

RESULTS

Homogenised and liver sausages with the addition of 5% flaxseed were given the highest scores by the consumers, although the colour changed with the addition of flaxseed. The spreadability and hardness of the liver sausages increased with the addition of flaxseed, whereas the texture of homogenised sausages did not change. Addition of flaxseed improved the fatty acids profile from a health point of view for both products, as a result of increasing n-3 fatty acids and overall polyunsaturated fatty acids content. Values for thiobarbituric acid reactive substances were higher in products with flaxseed and were observed to increase during storage.

CONCLUSION

The results of the present study indicate that it is possible to obtain products that are acceptable by consumers and, at the same time, are more healthy. A high level of α-linolenic acid in the sausages at a level of addition of 5% allows the product to be labelled with information regarding their high omega-3 fatty acid content. However, those products are more susceptible to oxidation. © 2016 Society of Chemical Industry.

Impact of extrusion processing conditions on lipid peroxidation and storage stability of full-fat flaxseed meal

Background

The full-fat flaxseed (Linum usitatissimum L.) meal has obtained relatively new flourished concept as food or feedstuff for the development of healthier products. It provides favorable balance of polyunsaturated, monounsaturated and saturated fatty acids. However, flaxseed meal may be susceptible to oxidation by exposure to various storage conditions which is extremely undesirable and produces toxic compounds to human health. Another consideration in the application of flaxseed meal relates to the presence of anti-nutritional compounds that need to be minimized using appropriate processing method. The present research work was conducted to evaluate the impact of extrusion processing conditions and storage of full-fat flaxseed meal on functional characteristics such as α-linolenic acid content, lipid peroxidation and sensory attributes.

Methods

The raw flaxseed meal was analyzed for cyanogenic glycosides, tannin and mucilage anti-nutritional compounds. Fatty acids composition was quantified by gas chromatography. The meal was extruded at barrel exit temperature (100–140 °C), screw speed (50–150 rpm), feed rate (30–90 kg/h) and feed moisture (10–30 %) for reduction of anti-nutritional compounds. The raw and extruded meals were stored for a ninety-day period under room conditions (20–25 °C). Lipid peroxidation was analyzed by peroxide, free fatty acids, conjugated dienes, total volatiles and malondialdehyde assay. Color, aroma and overall acceptability attributes were evaluated by sensory multiple comparison tests.

Results

The raw flaxseed meal possessed significant amount of anti-nutritional compounds, lipid and α-linolenic acid contents. The extrusion processing at high barrel exit temperature (140 °C) significantly reduced the cyanogenic compounds (84 %), tannin (73 %) and mucilage (27 %) in the flaxseed meal. The α-linolenic acid content and lipid peroxidation did not significantly change after extrusion processing or during storage at the end of 60 days. Fluctuations in sensory attributes occurred during storage, but at the end of 90 days, only the extruded samples presented negative effect and showed lowest consumer acceptability.

Conclusions

The present study suggested that extrusion of flaxseed meal at optimum conditions and stored for 60 days did not change the stability of full-fat flaxseed meal and can be used as supplement or ingredient for the production of various healthier products.

Proceedings from the 2013 Canadian Nutrition Society Conference on Advances in Dietary Fats and Nutrition

The science of lipid research continues to rapidly evolve and change. New knowledge enhances our understanding and perspectives on the role of lipids in health and nutrition. However, new knowledge also challenges currently held opinions. The following are the proceedings of the 2013 Canadian Nutrition Society Conference on the Advances in Dietary Fats and Nutrition. Content experts presented state-of-the-art information regarding our understanding of fish oil and plant-based n-3 polyunsaturated fatty acids, nutrigenomics, pediatrics, regulatory affairs, and trans fats. These important contributions aim to provide clarity on the latest advances and opinions regarding the role of different types of fats in health.

Preparation and storage stability of flaxseed chutney powder, a functional food adjunct

Flax (Linum usitatissimum L.) chutney powder (FSCP), a palatable functional food adjunct was prepared by mixing roasted and powdered flaxseeds with other selected spice ingredients. The protein content of these powders was 24.2% and 23.4% in flaxseed powder (FSP) and FSCP respectively. Total polyphenol content of FSP and FSCP was 439 and 522 mg/100 g respectively. The free fatty acid content of FSCP increased from 0.38 to 1.03 after 6 months storage. The critical moisture content for FSP and FSCP was 10.2 and 13.5%, which were equilibrated at 82 and 68% RH respectively and the ERH studies indicated both the powders are non-hygroscopic in nature. Overall sensory quality of FSCP served with cooked rice scored 'good' (7.4) even after 6 months of storage.

Effect of cyclolinopeptides on the oxidative stability of flaxseed oil

Polar compounds present in flaxseed oil increase its oxidative stability. Flaxseed oil becomes less stable to oxidation when filtered with silica. This observation may be linked to antioxidant compounds present in flaxseed oil. Flaxseed oil was passed over a silica adsorbent column to remove polar compounds. The polar compounds were then eluted from the silica absorbant using a series of increasingly polar solvents. The polar fractions from flaxseed oil were then added back to silica-treated flaxseed oil to determine the impact of fractions containing polar compounds on oxidative stability (induction time) at 100 °C. A polar fraction containing mainly cyclolinopeptide A (CLA, 1), but also containing β/γ- and δ-tocopherol increased the induction time of silica-treated flaxseed oil from 2.36 ± 0.28 to 3.20 ± 0.41 h. When oxidative stability was determined immediately after addition of the polar fractions other flaxseed fractions and solvent controls did not affect oil stability. However, when the oxidative stability index (OSI) test was delayed for three days and oil samples were held at room temperature after the addition of the polar fractions to the flaxseed oil, it was observed that the control oil treated with silica had become highly sensitive to oxidation. A polar fraction containing a mixture of CLs (1, 5, 7, 9, 11), improved the oxidative stability of peptide-free oil with respect to the control when the OSI measurement was made three days after adding the fraction. In addition, effects of 1 on the oxidative stability of peptide-free oil containing divalent metal cations was investigated.

Effect of flaxseed flour incorporation on the physical properties and consumer acceptability of cereal bars

Extensive research has revealed numerous nutritional and health benefits of flaxseed due primarily to its nutrients content. The objective of this study was to evaluate the effect of flaxseed flour addition on the physical and sensory characteristics of cereal bars. Four formulations of the flaxseed cereal bars were prepared by partially replacing oats with flaxseed flour added at levels of 0 (control), 6%, 12% and 18%. There were no significant differences ( p > 0.05) in water activity, moisture and firmness values between the flaxseed bars and control. Flaxseed addition significantly ( p < 0.05) decreased lightness and increased redness of the bars. There were no significant differences ( p > 0.05) between the 12% flax cereal bars and the control with respect to sensory attributes and overall acceptability. The overall acceptability for both 12% flax bars and the control was in between ‘like moderately’ and ‘like slightly’ on the 9-point hedonic scale. The overall acceptability was most highly correlated with flavor acceptability for both control ( r = 0.80) and 12% flax ( r = 0.82) cereal bars. Flaxseed bars provided 12% dietary fiber of the daily recommended value. These results indicated that flaxseed flour incorporation up to 12% substantially enhanced the nutritional qualities of the cereal bars without affecting their sensory and quality properties.

Physical and sensory characteristics of cookies prepared with flaxseed flour

BACKGROUND

Flaxseed has many health benefits and is considered a functional food ingredient. Flaxseed flour (0-18%) was used to partially replace wheat flour in cookies and its effects on the physical and sensory characteristics of the cookies were investigated. A correlation analysis was conducted between the instrumental and sensory data.

RESULTS

The cookie dough stickiness significantly (P < 0.05) decreased in relation to higher percentages of flaxseed flour. The 18% flaxseed cookies had the firmest texture, darkest color and lowest water activity. The 18% flaxseed cookies had the greatest spread ratio. However, this resulted in cookies of unacceptable quality properties. In consumer acceptance tests, cookies made with 6% and 12% flaxseed flour had the highest rating among all sensory attributes, while the 18% flaxseed cookies had the lowest sensory scores. The flavor attribute was most highly correlated with the overall acceptability (r = 0.90).

CONCLUSION

Results indicated that flaxseed flour can be incorporated in cookies as a partial replacement up to 12% of wheat flour without negatively affecting the physical and sensory quality. The correlation results suggest that the flaxseed flavor attributes best predict consumer preference for overall acceptability, though texture and color attributes also contribute.

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

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.

Flaxseed: a potential source of food, feed and fiber

Flaxseed is one of the most important oilseed crops for industrial as well as food, feed, and fiber purposes. Almost every part of the flaxseed plant is utilized commercially, either directly or after processing. The stem yields good quality fiber having high strength and durability. The seed provides oil rich in omega-3, digestible proteins, and lignans. In addition to being one of the richest sources of α-linolenic acid oil and lignans, flaxseed is an essential source of high quality protein and soluble fiber and has considerable potential as a source of phenolic compounds. Flaxseed is emerging as an important functional food ingredient because of its rich contents of α-linolenic acid (ALA), lignans, and fiber. Lignans appear to be anti-carcinogenic compounds. The omega-3s and lignan phytoestrogens of flaxseed are in focus for their benefits for a wide range of health conditions and may possess chemo-protective properties in animals and humans. This paper presents a review of literature on the nutritional composition of flaxseed, its health benefits, and disease-prevention qualities, utilization of flaxseed for food, feed, and fiber, and processing of flaxseed.

Processing and cooking effects on lipid content and stability of alpha-linolenic acid in spaghetti containing ground flaxseed

Research was conducted to determine the effect of processing and cooking on the content of hexane-extractable lipid and the stability of alpha-linolenic acid (ALA) in spaghetti fortified with ground flaxseed. Lipid content, ALA, and free fatty acids (FFA) were lower in dried spaghetti samples than in the original semolina-flaxseed mixture. The data indicate that the decline in lipid, ALA, and FFA contents occurred during the extrusion process. In contrast, conjugated diene levels were greater in dried spaghetti than in the corresponding premix. Conjugated diene level was similar for spaghetti samples dried using low- or high-temperature drying cycles, and was lower in cooked than in uncooked spaghetti. The low levels of FFA and conjugated diene indicate that ALA remained stable during processing and cooking of spaghetti fortified with ground flaxseed.