Effect of germination on vitamin C,phenolic compounds and antioxidant activity in flaxseed (Linum usitatissimum L.)

Flaxseed (Linum usitatissimum L.) is well known for its health benefits and chemical composition. This study aimed to evaluate the dynamic changes caused by germination in vitamin C, phenolic compounds and antioxidant activities of flaxseed. It was observed that eight‐day germination of flaxseed sprouts caused increases in phytochemical contents, that is 22.1‐fold increase in vitamin C, 2.67‐fold increase in phenolics and 5.48‐fold increase in flavonoid contents as compare to initial concentration in flaxseeds on dry weight basis. The stimulation was also noted in the three identified phenolic acid ingredients including caffeic acid, p‐coumaric acid and ferulic acid. Similarly, the total PSC and ORAC values of flax sprouts at day 8 increased by 3‐ to 4‐folds compared to nongerminated flaxseeds. It is revealed that comparatively, 8‐day germination of flax sprouts leads to a significant increase in vitamin C, phenolic constituents and total antioxidant activities than those of flaxseeds.     

Effects of germination on tocopherol,secoisolarlciresinol diglucoside,cyanogenic glycosides and antioxidant activities in flaxseed (Linum usitatissimum L.)

The changes in chemical composition and antioxidant activities of brown and golden flaxseeds (Linum usitatissimum L.) during 5-day germination were investigated. Flaxseeds germinated in a dark and closed incubator at the temperature of 25 °C. With noticeable reduction in fat content, germinated flaxseeds were determined higher percentage of linolenic acid. The total phenolic content and antioxidant activities increased with germination time. The highest amount of secoisolarlciresinol diglucoside (SDG) was found in 2-day germinated brown and golden flaxseeds, which increased 1.04-fold and 1.09-fold, respectively, and germinated flaxseed oil was found rich in SDG. Intriguingly, germination increased the α-tocopherol content from 0 to 4.58 mg per 100 g and 0 to 7.83 mg per 100 g in brown and golden flaxseeds while γ-tocopherol decreased. Germination process also reduced the total content of cyanogenic glucosides, the content of linustatin, neolinustatin and lotaustralin decreased significantly, but caused an increase in the content of linamarin. Therefore, germination can be utilised as an effective method to improve the nutritional value of flaxseed.     

Carboxymethyl derivatives of flaxseed (Linum usitatissimum L.) gum: characterisation and solution rheology

Carboxymethyl ether moieties were introduced to flaxseed (Linum usitatissimum L.) gum (FG) by reacting gum with monochloroacetic acid (MCA). Effects of ether forming reaction conditions, temperature, NaOH concentration and molar ratio of FG (anhydroxylose equivalent) to MCA, on the degree of substitution (DS) were investigated. Treatment at 70 °C, with 7.0 m NaOH, and molar ratio of MCA to FG of 10:1 over 3 h produced a polysaccharide with a DS of 0.824 ± 0.012. Both surface morphology and thermal behaviour were modified. Solutions of FG (0.5–4.0%, w/v) exhibited shear‐thinning behaviour where viscosity decreased with decreased FG concentration. After carboxymethylation, modified polymer solutions also exhibited shear‐thinning behaviour, where dynamic viscosity was lower than that of native FG solutions at the same concentration. The dynamic viscosities were lower for solutions of modified FG with higher DS and also lower for solutions made at lower FG concentrations (0.5–4.0%, w/v). A more liquid‐like behaviour with increasing FG DS was indicated as storage modulus G′ and loss modulus G″ decreased and became more frequency dependent. The substitution of hydroxyl groups with carboxymethyl groups suppressed entanglement between FG polysaccharide chains by reducing intermolecular association.     

Effect of seed moisture content on flaxseed (Linum usitatissimum L.) milling and milled product characteristics

BACKGROUND: Research was conducted to determine the effect of seed moisture content on flaxseed milling and milled product characteristics. Flaxseed with 55, 80, and 105 g kg^?1 moisture contents were milled on a centrifugal cutting mill (CCM) configured with a 0.475 and 9.5 kg min^?1 feed rate; a hammer mill configured with a blunt hammer face, 0.35 kg min^?1 feed rate, 3.1 mm screen, and 2,795 m min^?1 hammer tip speed; and a hammer mill configured with a sharp hammer face, 0.35 kg min^?1 feed rate, 2.7 mm screen, and 3,870 m min^?1 hammer tip speed. RESULTS: Fine‐particle fraction (≤600 µm) yield was greater from flaxseed with 55 than with 105 g kg^?1 moisture content. Surface lipid content correlated positively with fine‐particle yield (r = 0.82, P = 0.01). At each moisture level, the surface lipid extracted from the fine‐particle fraction was greater with 9.5 than 0.475 kg min^?1 configuration of CCM and tended to be greater with the blunt than with the sharp hammer configuration of the hammer mill. CONCLUSION: Results indicated that flaxseed was more difficult to mill to a fine particle size at high than at low moisture content regardless of the mill configuration. Enhanced lipid oxidation was not detected in freshly milled flaxseed. Copyright © 2009 Society of Chemical Industry     

Variation of composition and functional properties of gum from six Canadian flaxseed (Linum usitatissimum L.) cultivars

Flaxseed gum (FG) was prepared from six Canadian flaxseed (Linum usitatissimum L.) cultivars. Yield, neutral sugar content, acidic sugar content and protein content varied significantly among cultivar FG extracts. Zeta potential (?16.4 to ?27.4 mV) and rheological properties of solution were cultivar dependent. Solutions prepared with CDC Glas FG had the highest viscosity (2.984 Pa?s), while CDC Sorrel produced the lowest (0.048 Pa?s). FG solutions exhibited pseudoplastic shear‐thinning behaviour. Viscosity of FG solution increased with concentration, while viscosity and pseudoplasticity decreased with increased temperature. NaCl addition decreased solution viscosity while adding sucrose increased viscosity. FG solutions prepared from Flanders and CDC Sorrel had the highest and lowest emulsion activity index, respectively, while solutions of CDC Arras and CDC Bethune FG had the lowest and highest emulsion stability, respectively. Findings presented here provide information that could enable greater utilisation in food, cosmetic and pharmaceutical industries as thickeners and/or emulsifiers.     

Effects of growing site and nitrogen fertilization on biomass production and lignan content of linseed (Linum usitatissimum L.)

There is strong evidence that the lignan precursors from vegetable material, secoisolariciresinol (seco) and matairesinol (mata), are major sources to support the development of lignans in the mammalian colon. Recent studies have shown these active agents to have anticancer properties, especially for mammary or prostatic carcinomas. Linseed is currently by far the best‐known source of seco and mata. To support the development of a food supplement, cultivars of linseed were tested at two sites and under increasing nitrogen supply to investigate how the lignan content is affected. The results indicated that the nitrogen supply did not affect the content of seco and mata at either site. A significant difference in seed yield could be measured between the sites, but the overall lignan content—even though significant—was less affected. The main effects were relatively similar at both sites and derived from the cultivars, indicating that the lignan content is very much dependent on genetic predisposition. Copyright © 2005 Society of Chemical Industry     

Properties of extruded corn snacks with common flax (Linum usitatissimum L.) and golden flax (Linum flavum L.) pomace

An attempt was undertaken in this study to produce extruded snacks based on maize semolina with the addition of pomace from common flax (Linum usitatissimum L.) and golden flax (Linum flavum L.). Study results showed that increasing pomace content in the extrudates made their expansion ratio and colour lightness to decrease, and their mechanical properties to increase. The analysis of all sensory attributes demonstrated that the panellists did not notice any statistically significant differences between the snacks without pomace addition and those with 5% flax pomace. Flax pomace addition in the amount exceeding 10% made the product unacceptable by the panellists. No statistically significant difference was observed in most of the evaluated traits between the snacks containing of pomace from common flax and golden flax, except for the colour.     

In vitro digestibility of flaxseed (Linum usitatissimum L.) protein: effect of seed mucilage,oil and thermal processing

Flaxseed (Linum usitatissimum L.) protein is reported to release physiologically important amino acids and bioactive peptides during gastrointestinal (GI) digestion. The effect of seed mucilage and oil and thermal processing on the in vitro protein digestibility (IPD) of flaxseed protein was assessed under simulated GI digestion. Protein in ground whole flaxseed that contained both mucilage and oil had the lowest digestibility (12.61%). Baking and boiling before size reduction significantly (P < 0.05) improved the IPD (31.77% and 28.04%, respectively). Further increase in IPD occurred when mucilage (51.00%) and both mucilage and oil (66.79%) were removed. Isolated flax protein had a similar IPD value (68.00%) as the mucilage and oil–removed flaxseed. The polypeptide of approximately 13 kDa showed resistance to GI digestion compared with other polypeptides of all these treated seeds. Removal of oil and mucilage as well as thermal treatment enhanced protein digestibility of flaxseed.     

The effective parameters for subcritical water extraction of SDG lignan from flaxseed (Linum usitatissimum L.) using accelerated solvent extractor

The aim of this study was to investigate the effective parameters for subcritical water extraction of secoisolariciresinol diglucoside (SDG) lignan from flaxseed using accelerated solvent extractor. For this aim, the influence of extraction parameters such as material shape (flaxseed, ground flaxseed meal and flaxseed meal sticks), temperature (120, 140, 160 and 180 °C), extraction time (15, 30, 60 and 90 min), pressure (1.500 and 2.000 psi), fresh water (5, 40 and 100 %) and sample amount (5 and 10 g) was studied. SDG lignan analysis has been carried out by LC–MS/MS. It was shown that material shape, temperature, extraction time and sample amount had significant effect on SDG lignan content in water extracts (p < 0.05). The highest amount (12.94 mg/g) and extraction yield (72.57 %) were obtained at 180 °C for 15 min, 1.500 psi and 40 % fresh water using 5 g of flaxseed meal sticks.     

Characterisation of germinated fenugreek (Trigonella foenum‐graecum L.) seed fractions

Germinated fenugreek seeds were separated into endosperm, seed coat and sprouts with an overall yield of 78%. Germinated endosperm, sprouts and ungerminated endosperm contained 39.25%, 36.12% and 48.20% protein, respectively. Germinated seed coat had 55.80% insoluble and 86.96% total dietary fibre, whereas ungerminted seed coat had 31.90% and 77.10% respectively. Sprouts were rich in polyphenols (97.55 mg per 100 g). At 200 ppm concentration, the antioxidant activity of the extracts of seed coat, sprouts and endosperm from germinated fenugreek seeds was 79.87%, 49.05%, and 13.42% where as the seed coat and endosperm of ungerminated fenugreek exhibited 90.94% and 10.13% antioxidant activity respectively. The GC analysis of the ester derivatives of the fixed oils of above fractions showed discernable changes in fatty acid profile. Atomic absorption spectroscopy analysis of the above fractions showed overall differences in their mineral content particularly calcium, zinc, copper, iron, potassium, manganese and magnesium.     

青海亚麻籽中木脂素含量测定及抗氧化活性分析

目的:为促进青海地区亚麻籽及其加工副产物的高值化利用.方法:以青海省20种不同产地、品种亚麻籽为原料,采用反相高效液相色谱法测定其木脂素开环异落叶松酚葡萄糖苷和开环异落叶松脂素含量,并以DPPH自由基和ABTS自由基清除能力评价其抗氧化活性.结果:青海省不同产地、品种的亚麻籽中木脂素含量差异显著(P＜0.05),开环异...     

Nitrogen extractability and buffer capacity of defatted linseed (Linum usitatissimum L.) flour

Defatted linseed flour was prepared from cold-pressed seed meal via hexane extraction of the residual oil, followed by removal of the major portion of the hulls through grinding and sieving (sieve size 0.25 mm). The resulting flour had 50% protein on a dry basis compared with 40% contained by the whole seed on an oil-free dry basis. Nitrogen extractability of the defatted flour in water was not influenced by the length of the extraction period but an increased extraction was observed at higher solid:liquid ratios up to the studied limit of 1:40. The smallest amount of nitrogen (20%) was extracted in the pH range 4.0–4.6 and the greatest (80%) at pH 12.0. Addition of NaCl (0.1–1.0 M) broadened the pH range of minimum nitrogen extractability and shifted it towards lower pH region. At higher concentrations (0.6 and 1.0 M) NaCl markedly increased nitrogen extractability in the pH range of 4.0 to 8.0. Precipitation of protein from an extract at pH 10.0 was maximum (77%) at pH 4.1. A higher buffer capacity of the flour was observed in the acidic medium (0.204 mmol HCl g^?1 flour) than in the alkaline medium (0.096 mmol NaOH g^?1 flour).