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.     

食物加工方法对亚麻木酚素稳定性影响的研究

通过分析蒸、煮、炒、炸样品中亚麻木酚素(SDG)的含量,研究了食物的加工方法、加工时间以及用于分解生氰糖苷的微波处理对亚麻籽粉中SDG的影响。结果显示,亚麻籽粉可以作为一种健康食物补充剂添加到大多数的食物中,食物加工方法对其中SDG含量的影响不大,但亚麻籽粉可能并不是一种有效的汤类食物原料。     

HPLC检测亚麻籽中开环异落叶松树脂酚二葡萄糖苷的超声波前处理工艺研究

以亚麻籽为原料,对HPLC检测亚麻籽中开环异落叶松树脂酚二葡萄糖苷(SDG)的超声波前处理工艺进行了研究。通过单因素试验分别考察了萃取溶剂、料液比、超声时间、超声温度、超声功率、萃取次数对测定亚麻籽中SDG含量的影响。结果表明,超声波前处理结合HPLC检测亚麻籽中SDG的最佳超声波前处理条件为:以甲醇为萃取溶剂,料液比1∶20,超声时间2 h,超声温度35℃,超声功率800 W,萃取次数3次。在最佳条件下,测得亚麻籽中SDG含量为11.40 mg/g。     

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.     

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.     

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.     

Comparison of lignans and phenolic acids in different varieties of germinated flaxseed (Linum usitatissimum L.)

The study aimed to evaluate the biosynthesis and accumulation of lignans, phenolic acids and also the antioxidant activities in 15 varieties of flax sprouts. The differential contents of lignans (13.30–8987 μg g⁻¹) and phenolic acids (72.55–597.1 μg g⁻¹) among 15 varieties of flax sprouts were observed. The total antioxidant activities ranged from 147.2 to 332.8 μmol TE g⁻¹ in the flax sprouts. The expression levels of five genes in the lignin synthetic pathway were analysed using RT-qPCR, and the results showed dramatical differences among different flax sprouts. Relatively dispersed analysis was showed by principal component analysis (PCA), and 15 flax sprouts were grouped by hierarchical cluster analysis (HCA) based on their phenolic acids, lignan compounds, length, gene expression and antioxidants after germination, primarily in relation to variety specificity. Present results would be instructive guidance for bio-fortification breeding and functional foods innovation in flaxseeds.     

萌发提升亚麻籽营养品质的研究

为了探究亚麻籽萌发后的品质变化以及实现亚麻籽芽苗这种新型资源产品的高值化加工利用,本文从蛋白质、脂肪、氨基酸、维生素、矿物质、氢氰酸等组分含量角度出发,对比分析了亚麻籽萌发前后的营养成分。结果表明,亚麻籽经萌发处理后,氰化物的含量减少8.95%,蛋白质含量增加了57.77%,脂肪含量下降了23.60%,氨基酸总量增加了61.67%,必需氨基酸总量增加了62.77%,维生素C含量大幅提高,高达77.37 mg/100 g,钾钙镁等矿物质总含量增加为原来的126%。萌发能使亚麻籽营养品质得到提升。     

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     

Secoisolariciresinol diglucoside determination in flaxseed (Linum usitatissimum L.) oil and application to a shelf life study

A high-performance liquid chromatographic (HPLC) reliable and sensitive method with diode array detection (DAD) system has been developed for the determination of secoisolariciresinol diglucoside (SDG) in flaxseed oil. An analytical methodology based on the sample extraction with methanol/water (80:20, v/v), subsequent purification of the sample and analysis of the extract by HPLC/DAD is proposed for the determination of SDG in flaxseed oil. The coefficient of determination of the standard calibration curve was 0.999, the limit of detection was 0.08 μg/mL, and the limit of quantification was 0.27 μg/mL. The recovery test was conducted adding four different concentrations of standard solution to the blank sample. The recovery ranged from 90% to 95%. To our knowledge, the presence and quantification of SDG in flaxseed oil has never been reported. The proposed method was tested to study the variation in SDG content in flaxseed oil during a shelf-life test to verify its applicability in quality control for oil industries. The dark and the low temperature of storing together allowed to preserve SDG. A slight pro-oxidant effect was observed for the addition of antioxidant to the flaxseed oil.     

开环异落叶松树脂酚的提取及其对乳液稳定性的影响研究

以含50%开环异落叶松树脂酚二葡萄糖苷(SDG)的亚麻木酚素粗提物(50%SDG)为水解原料,对制备开环异落叶松树脂酚(SECO)粗提物的HCl浓度和水解时间进行优化,进一步通过溶剂萃取、真空冷冻干燥工艺制备SECO粗提物,并将其应用于磷脂-亚麻籽油乳液体系中,研究水解前后亚麻木酚素粗提物对磷脂-亚麻籽油乳液在65℃高温储藏过程中稳定性的影响。结果表明:在HCl浓度1 mol/L、水解时间120 min的条件下水解,可制备SECO含量为65%的SECO粗提物(65%SECO);在磷脂-亚麻籽油乳液高温储藏(65℃)过程中,65%SECO组乳液粒径无显著变化,但对照组和50%SDG组乳液粒径增大;与对照组乳液相比,储藏7 d,65%SECO和50%SDG可分别将乳液中氢过氧化物含量降低11%和27%。由此可见,在磷脂-亚麻籽油乳液的高温储藏(65℃)过程中,50%SDG具有较好的抑制油脂氧化的效果,但通过水解制备的65%SECO能显著提高磷脂-亚麻籽油乳液的物理稳定性。     

Effect of extraction conditions on composition,surface activity and rheological properties of protein isolates from flaxseed (Linum usitativissimum L)

Flaxseed protein isolates were prepared by micellisation (FM) and isoeletric precipitation (FI). The influence of preparation conditions on composition and functional properties was investigated. Contents of 0.6% phytic acid and 2.3% pentosans were found for FI, whereas FM was almost phytic acid‐free and had a low content of pentosans (0.6%). Chromatography and electrophoresis identified the 11S globulin (linin) as the main protein fraction in both isolates. Protein solubility, water‐ and oil‐binding capacities, emulsification and rheological properties of dispersions and gels were measured at pH 8 and 3. For the latter, interactions of protein with phytic acid and pentosans are highly probable. FI possesses a lower solubility (about 40–50%) and an overall higher water‐binding capacity than FM. For FI dispersions a higher storage modulus G′ than loss modulus G″ was measured, clearly pointing to the formation of protein networks. Moreover, FI formed stronger gels than FM (G′ about fivefold). The emulsifying activity, however, was distinctly lower for FI. These results point to enhanced complexation and aggregation of the isoelectric‐precipitated protein isolate. © 2002 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.