Lipids and antioxidants in groats and hulls of Swedish oats (Avena sativa L)

Concentrations and compositions of total lipids (TL), fatty acids, tocopherols and tocotrienols, avenanthramides and free hydroxycinnamic acids were determined in groats and hulls from single samples of seven Swedish oat cultivars. Total antioxidant capacity (TAC) was measured using the radical 1,1‐diphenyl‐2‐picrylhydrazyl as substrate. Results were evaluated by principal component analysis. Consistent differences in value of the variables analysed in groats and hulls were found, groats having higher concentrations of all compounds analysed except free cinnamic acids. Concentrations of E‐vitamers (especially tocotrienols) were high in both groat and hull samples with high TL. Avenanthramides were high in hull samples with high TL, but this was not found in groats. Free cinnamic acids did not follow TL in either groats or hulls. TAC was generally higher in groats than in hulls. The within‐group variation in TAC was less pronounced than that in chemical composition, especially in groats. The results did not suggest any strong relationship between TAC and individual antioxidants. © 2002 Society of Chemical Industry     

Effect of unmalted oats (Avena sativa L.) on the quality of high-gravity mashes and worts without or with exogenous enzyme addition

Barley malt is the preferred brewing material these days because of its high extract content and high enzyme activities. However, when substituting malted barley with oats to create a unique beer flavor and aroma, endogenous malt enzymes become the limiting factor. Therefore, the objectives of this study were to evaluate the effect of 10–40 % unmalted oats on the quality of high-gravity mashes/worts and to investigate the limitations of endogenous malt enzymes as well as the benefits of the application of industrial enzymes. The enzyme mix Ondea^® Pro was found to be particularly suitable for mashing with unmalted oats and was therefore used in the present rheological tests and laboratory-scale mashing trials. In order to gain detailed information about the biochemical processes occurring during mashing, the quality of mashes was comprehensively analyzed after each mash rest using standard methods described by Mitteleuropäische Brautechnische Analysenkommission and Lab-on-a-Chip capillary electrophoresis. Mashing with up to 40 % oats resulted in increased mash consistencies, color/pH (20 °C) values, β-glucan concentrations, wort viscosities 12.0 %, and filtration times as well as decreased FAN and extract contents. The application of Ondea^® Pro enormously increased the color of worts despite lower pH values but considerably improved the quality and processability of 30 or 40 % oat-containing mashes/worts. However, the substitution of up to 20 % barley malt with unmalted oats can easily be realized without the addition of exogenous enzymes.     

燕麦抗冻蛋白对面筋蛋白冻融稳定性的影响

将燕麦抗冻蛋白(AsAFPs)加入到小麦面筋蛋白中,通过测定冻融循环条件下的小麦面筋蛋白的持水性、持油性、乳化和乳化稳定性、二级结构和弛豫时间,研究AsAFPs对冻融小麦面筋蛋白品质的影响。结果表明:经过5次冻融循环后,小麦面筋蛋白的持水率由92.8%降到87.8%,而AsAFPs的加入能够减缓冻融循环过程中水分的流失,使小麦面筋蛋白的持水率由92.8%降到89.8%;小麦面筋蛋白持油性呈上升趋势,AsAFPs的加入可以减少疏水键的暴露,使小麦面筋蛋白持油性低于对照组;小麦面筋蛋白的乳化性降低,乳化稳定性升高,加入AsAFPs后,其乳化性升高,乳化稳定性降低;小麦面筋蛋白无规则卷曲、α-螺旋整体呈下降趋势,而β-折叠和β-转角整体呈上升趋势,加入AsAFPs后无规则卷曲、α-螺旋下降的幅度变小;小麦面筋蛋白的冻结水逐渐向自由水转变,AsAFPs组小麦面筋蛋白结合水和自由水的含量变化幅度均小于对照组。     

An electron spin resonance study of radicals induced by radiation in oat (Avena sativa L.)

A detailed electron spin resonance (ESR) investigation of the spectroscopic features and kinetic behaviours over a range of temperatures of the long‐life free radicals induced in a sample of ground oat that had been irradiated with γ‐radiation is reported. Unirradiated ground oat exhibited a weak, broad single‐line ESR spectra centered at g = 2.0048 ± 0.0008. The structure of this radical is unknown and is assigned as radical III in this work. The γ‐irradiation of oats yields radical III and other radical species. Although all these species are stable at 77 K, some of them are very unstable at room temperature. A model based on three radical species (designated I, II and III) was used to describe the room temperature spectra of their decay at room and at high temperatures. Annealing studies at six different temperatures were used to determine the kinetic behaviour and activation energies of the radicals induced by radiation. A dose–response curve was also constructed and it was concluded that ground oat is potentially a good dosimetric material. The presence of an ESR signal after a storage time of 90 days was interpreted as providing an opportunity to distinguish irradiated from unirradiated oats.     

Inhibition of Fusarium graminearum growth in flour gel cultures by hexane-soluble compounds from oat (Avena sativa L.) flour

Fusarium head blight, incited by the fungus Fusarium graminearum, primarily affects wheat (Triticum aestivum) and barley (Hordeum vulgarum), while oat (Avena sativa) appears to be more resistant. Although this has generally been attributed to the open panicle of oats, we hypothesized that a chemical component of oats might contribute to this resistance. To test this hypothesis, we created culture media made of wheat, barley, and oat flour gels (6 g of flour in 20 ml of water, gelled by autoclaving) and inoculated these with plugs of F. graminearum from actively growing cultures. Fusarium growth was measured from the diameter of the fungal plaque. Plaque diameter was significantly smaller on oat flour cultures than on wheat or barley cultures after 40 to 80 h of growth. Ergosterol concentration was also significantly lower in oat cultures than in wheat cultures after growth. A hexane extract from oats added to wheat flour also inhibited Fusarium growth, and Fusarium grew better on hexane-defatted oat flour. The growth of Fusarium on oat flour was significantly and negatively affected by the oil concentration in the oat, in a linear relationship. A hexane-soluble chemical in oat flour appears to inhibit Fusarium growth and might contribute to oat's resistance to Fusarium head blight. Oxygenated fatty acids, including hydroxy, dihydroxy, and epoxy fatty acids, were identified in the hexane extracts and are likely candidates for causing the inhibition.     

Brewing with up to 40% unmalted oats (Avena sativa) and sorghum (Sorghum bicolor): a review

Beer production with up to 40% unmalted cereals such as barley, wheat, rice and maize is legally allowed and thus practised in many European countries. The use of oats and sorghum as brewing adjuncts has great potential for creating new beer types/flavours and saving costs. In contrast to oats, sorghum is not as well known within Europe; however, its versatility makes it a very promising crop for exploitation in these temperate‐zone regions. This review describes the brewing‐relevant characteristics of unmalted oat and sorghum grain, investigates the role and properties of endogenous/exogenous enzymes during mashing, discusses the processability/quality of mashes, worts and beers produced with up to 40% oat or sorghum adjunct, and examines the effectiveness/limitations of endogenous enzymes as well as the benefits of the application of exogenous enzymes. Copyright © 2014 The Institute of Brewing & Distilling     

Effects of water-saving superabsorbent polymer on antioxidant enzyme activities and lipid peroxidation in oat (Avena sativa L.) under drought stress

BACKGROUND: Drought stress significantly limits oat (Avena sativa L.) growth and productivity. Thus an efficient management of soil moisture and study of metabolic changes in response to drought are important for improved production of oat. The objective was to gain a better understanding of drought tolerance mechanisms and improve soil water management strategies using water‐saving superabsorbent polymer (SAP) at 60 kg ha^?1 under three irrigation levels (adequate, moderate and deficit) using a new type of hydraulic pressure‐controlled auto irrigator. RESULTS: The results showed that the relative water content and leaf water potential (ψ₁) were much higher in oats treated with SAP. Although the SAP had little effect on plant biomass accumulation under adequate and moderate irrigation, it significantly increased the biomass by 52.7% under deficit irrigation. Plants treated with SAP under deficit irrigation showed a significant decrease in superoxide dismutase, catalase, peroxidase, ascorbate peroxidase and glutathione reductase activities in leaves compared with control plants. CONCLUSION: Our results suggested that drought stress leads to production of oxygen radicals, which results in increased lipid peroxidation and oxidative stress in the plant, and the application of SAP could conserve soil water, making same available to plants for increased biomass accumulation and reduced oxidative stress especially under severe water stress. Copyright © 2010 Society of Chemical Industry     

Characteristics of hemp (Cannabis sativa L.) seed oil

Characteristics of oil extracted from hempseeds subjected to microwave treatments were evaluated. Microwave treatment improved oil yield, increased carotenoid and other pigment contents and decreased p-anisidine value without significant changes in other properties. Hempseed oil showed absorbance in the UV-B and UV-C ranges with potential for use as a broad spectrum UV protectant. β-Tocopherol concentrations increased, while the major tocopherol, γ-tocopherol, and fatty acid composition of the oil were unaffected by microwave treatment of hempseed. Hempseed oil showed high kinetic stability during heating and cooling, as characterized by differential scanning calorimetry (DSC). Microwave treatment shifted the melting range of oils to lower temperatures and increased oxidation temperatures, suggesting increased protective effect upon heating.     

大麻蛋白的营养评价

本文以脱脂大麻籽粉为原料,采用碱溶酸沉法提取大麻分离蛋白(HPI)及其11S组分(HPI-11S)、7S组分(HPI-7S),对其进行氨基酸组成分析,并应用胃蛋白酶-胰蛋白酶体外消化模拟实验评价大麻蛋白的营养价值,结果表明:与大豆分离蛋白相比,大麻蛋白富含人体所需的必需氨基酸,消化性能更优,属优质蛋白质.     

亚麻荠籽压榨制油工艺的研究

对亚麻荠籽压榨制油及毛油精炼工艺条件进行了研究,得到其压榨制油工艺条件为:蒸炒温度110℃,蒸炒时间20 min,加水量5%。在最佳工艺条件下压榨2次,出油率较高(31.7%),饼中残油低(6.8%)。通过对精炼脱胶、碱炼脱酸、脱色、脱臭过程的考察,得到各个工段的主要参数。     

Studies on lipoxygenase from rice (Oryza sativa L.)

Lipoxygenase activity was studied in 10 scented and two non-scented rice varieties. Kinetic studies at different pH levels and time intervals revealed that the optimal activity was exhibited around pH 8 and at 15 min. Specific activities ranged from 40–85 units mg^?1 protein and all the scented varieties had lower values that non-scented ones.     

Partial characterization of lettuce (Lactuca sativa L.) polyphenol oxidase

Polyphenol oxidase (PPO) from garden lettuce (Lactuca sativa L.) was partially purified by ammonium sulphate ((NH₄)₂SO₄) precipitation and dialysis, and then some of its kinetic properties such as optimum pH and temperature, substrate specificity, thermal inactivation and inhibition were investigated. The total phenolic and protein contents of Lactuca sativa L. extracts were determined according to the Folin-Ciocalteu and Bradford methods, and found to be 304 mg/100 g on a fresh weight basis and 494 μg/mL, respectively. PPO activity was determined using 4-methylcatechol, catechol and pyrogallol as substrates. Kinetic parameters, K _m and V _max, were calculated from Lineweaver–Burk plots. According to V _max/K _m ratio, pyrogallol was the most suitable substrate, followed by catechol and 4-methylcatechol. The optimum temperature and pH values were 30, 40 and 30 °C; and 6.5, 8.0 and 7.5 for 4-methylcatechol, catechol and pyrogallol substrates, respectively. The thermal inactivation of PPO was investigated at 35, 55 and 75 °C. The enzyme activity decreased with increasing temperature. The effect of different inhibitors on partially purified Lactuca sativa L. PPO was spectrophotometrically investigated. For this purpose, tropolone, glutathione, ascorbic acid and 4-aminobenzoic acid were used to inhibit the activity of Lactuca sativa L. PPO at different concentrations. From the experimental results, it was found that glutathione was found to be the most potent inhibitor for Lactuca sativa L. PPO.     

Functional Properties of Dry Milled Fractions From Wild Oats (Avena fatua L.)

When processed into groats, wild oats provided meal, bran and flour fractions which contained 22, 28 and 18% protein, respectively. While nitrogen solubilities were low due to the steam treatments used to inactivate lipase, water hydration capacities of the wild oat products were high. Oil absorption characteristics of the bran were more than twice those of the flour but oil emulsions formed with wild oat products were poor. Starch contents of the meals and flours were 55 and 70%, respectively, and their Visco/Amylograph curves were characterized by low initial pasting temperatures, high peak viscosities at 95°C and setback values that were intermediate to those of corn flour.     

Arsenic accumulation and metabolism in rice (Oryza sativa L.)

The use of arsenic (As) contaminated groundwater for irrigation of crops has resulted in elevated concentrations of arsenic in agricultural soils in Bangladesh, West Bengal (India), and elsewhere. Paddy rice (Oryza sativa L.) is the main agricultural crop grown in the arsenic-affected areas of Bangladesh. There is, therefore, concern regarding accumulation of arsenic in rice grown those soils. A greenhouse study was conducted to examine the effects of arsenic-contaminated irrigation water on the growth of rice and uptake and speciation of arsenic. Treatments of the greenhouse experiment consisted of two phosphate doses and seven different arsenate concentrations ranging from 0 to 8 mg of As L(-1) applied regularly throughout the 170-day post-transplantation growing period until plants were ready for harvesting. Increasing the concentration of arsenate in irrigation water significantly decreased plant height, grain yield, the number of filled grains, grain weight, and root biomass, while the arsenic concentrations in root, straw, and rice husk increased significantly. Concentrations of arsenic in rice grain did not exceed the food hygiene concentration limit (1.0 mg of As kg(-1) dry weight). The concentrations of arsenic in rice straw (up to 91.8 mg kg(-1) for the highest As treatment) were of the same order of magnitude as root arsenic concentrations (up to 107.5 mg kg(-1)), suggesting that arsenic can be readily translocated to the shoot. While not covered by food hygiene regulations, rice straw is used as cattle feed in many countries including Bangladesh. The high arsenic concentrations may have the potential for adverse health effects on the cattle and an increase of arsenic exposure in humans via the plant-animal-human pathway. Arsenic concentrations in rice plant parts except husk were not affected by application of phosphate. As the concentration of arsenic in the rice grain was low, arsenic speciation was performed only on rice straw to predict the risk associated with feeding contaminated straw to the cattle. Speciation of arsenic in tissues (using HPLC-ICP-MS) revealed that the predominant species present in straw was arsenate followed by arsenite and dimethylarsinic acid (DMAA). As DMAA is only present at low concentrations, it is unlikely this will greatly alter the toxicity of arsenic present in rice.     

Grain accumulation of selenium species in rice (Oryza sativa L.)

Efficient Se biofortification programs require a thorough understanding of the accumulation and distribution of Se species within the rice grain. Therefore, the translocation of Se species to the filling grain and their spatial unloading were investigated. Se species were supplied via cut flag leaves of intact plants and excised panicle stems subjected to a ± stem-girdling treatment during grain fill. Total Se concentrations in the flag leaves and grain were quantified by inductively coupled plasma mass spectrometry. Spatial accumulation was investigated using synchrotron X-ray fluorescence microtomography. Selenomethionine (SeMet) and selenomethylcysteine (SeMeSeCys) were transported to the grain more efficiently than selenite and selenate. SeMet and SeMeSeCys were translocated exclusively via the phloem, while inorganic Se was transported via both the phloem and xylem. For SeMet- and SeMeSeCys-fed grain, Se dispersed throughout the external grain layers and into the endosperm and, for SeMeSeCys, into the embryo. Selenite was retained at the point of grain entry. These results demonstrate that the organic Se species SeMet and SeMeSeCys are rapidly loaded into the phloem and transported to the grain far more efficiently than inorganic species. Organic Se species are distributed more readily, and extensively, throughout the grain than selenite.     

The process of methylmercury accumulation in rice (Oryza sativa L.)

Recent studies have shown that rice consumption can be an important pathway of methylmercury (MeHg) exposure to humans in Hg mining areas and also in certain inland areas of Southwestern China. The seed of rice has the highest ability to accumulate MeHg compared to other tissues. The main objective of this study was to investigate the process of (MeHg) accumulation in rice seed (Oryza sativa L.) by monitoring MeHg levels in specific tissues of rice plants experiencing various levels of Hg multisource pollution during a full rice growing season. Four groups of experimental plantations were utilized, distributed among a rural artisanal Hg production site and a regional background control site. Our results suggest that the newly deposited Hg is more readily transformed to MeHg and accumulated in rice plants than Hg forms with an extended residence time in soil, and soil is the potential source of MeHg in the tissues of rice plants. MeHg in soil was first absorbed by roots and then translocated to the above-ground parts (leaf and stalk). During the full rice growing season only a very small amount of MeHg was retained in the root section. In the premature plant, the majority of MeHg is located in the leaf and stalk; however, most of this MeHg was transferred to seed during the ripening period.     

The apparent ileal digestibility of amino acids and the digestible energy content of naked oats (Avena sativa cv Bandicoot) fed to growing pigs

An experiment was conducted to determine the apparent ileal digestibility of amino acids and the digestible energy (DE) content of two samples of naked oats (Avena sativa cv Bandicoot) and to compare these parameters in wheat (Triticum aestivum cv Machete) and dehulled oats (groats; Avena sativa cv Echidna). Four Large White male pigs were fitted with simple T-piece ileal cannulae and allocated to experimental diets in a 4×4 Latin square design. Amino acid digestibility coefficients were determined after continuous eight hour collections of digesta over two consecutive days using acid-insoluble ash as an indigestible marker. Digestible energy was determined using grab samples of faeces. No significant difference between the four test cereals was found in the digestibility of all amino acids, except for proline and lysine. The apparent ileal digestibility of lysine in wheat (0·87) and two samples of naked oats (0·89 and 0·82, respectively) was lower (P<0·05) than dehulled oats (0·91). The mean DE value of the naked oats samples was 16·96 MJ kg⁻¹ (air-dry basis). The results suggest that Bandicoot naked oats and dehulled oats are superior amino acid and DE sources to wheat and have potential for use in weaner and grower pig diets. © 1998 SCI.     

燕麦油的精制及其抗过敏性与抗氧化性功效检测

通过脱胶、脱酸和脱色三步对燕麦粗油进行精制,并对燕麦油精制前后酸价、游离脂肪酸含量、碘价和皂化值进行测定.通过透明质酸酶体外抑制实验和大豆色拉油抗氧化实验对燕麦油抗过敏性和抗氧化性进行检测,证明其具有一定的抗过敏性和抗氧化性.