Showing papers on "Avena published in 2002"

Effects of commercial processing on levels of antioxidants in oats (Avena sativa L.).

Abstract: The effects of various commercial hydrothermal processes (steaming, autoclaving, and drum drying) on levels of selected oat antioxidants were investigated. Steaming and flaking of dehulled oat groats resulted in moderate losses of tocotrienols, caffeic acid, and the avenanthramide Bp (N-(4'-hydroxy)-(E)-cinnamoyl-5-hydroxy-anthranilic acid), while ferulic acid and vanillin increased. The tocopherols and the avenanthramides Bc (N-(3',4'-dihydroxy-(E)-cinnamoyl-5-hydroxy-anthranilic acid) and Bf (N-(4'-hydroxy-3'-methoxy)-(E)-cinnamoyl-5-hydroxy-anthranilic acid) were not affected by steaming. Autoclaving of grains (including the hulls) caused increased levels of all tocopherols and tocotrienols analyzed except beta-tocotrienol, which was not affected. Vanillin and ferulic and p-coumaric acids also increased, whereas the avenanthramides decreased, and caffeic acid was almost completely eliminated. Drum drying of steamed rolled oats resulted in an almost complete loss of tocopherols and tocotrienols, as well as a large decrease in total cinnamic acids and avenanthramides. The same process applied to wholemeal made from groats from autoclaved grains resulted in less pronounced losses, especially for the avenanthramides which were not significantly affected.

Differences between sensory profiles and development of rancidity during long-term storage of native and processed oat

Abstract: Cereal Chem. 79(3):367–375 Changes in the sensory attributes, lipid composition, and amounts of volatile and phenolic compounds of native and processed (germinated and dried) crushed oat were followed during a 12-month storage period. The influence of the chemical attributes on the sensory profiles of oats was analyzed by statistical multivariate techniques (PLS regression). During the storage period, significant changes in the sensory profiles of the native and processed oat groats were observed. The stability of oat groats was significantly increased through germination and subsequent drying because the chemical changes causing rancidity and bitterness developed more slowly in the processed oat when compared with the native oat. In native oat, the most intensive changes due to deterioration had already occurred after one month of storage, whereas in processed oat, these changes were perceived considerably later. Stored oat that had deteriorated was evaluated as being musty and earthy in odor and bitter and rancid in flavor. The accumulation of free fatty acids and volatile compounds related to lipid oxidation were closely correlated with the development of the undesired sensory attributes described above. The total amount of phenolic compounds, as well as the volatile aromatic and branched chain compounds derived mainly from protein degradation, showed a significant relationship with favorable sensory attributes such as roasted odor and flavor. Lipid oxidation occurred during the storage and was observed both in the polar and in the nonpolar lipid classes of native oat, whereas in the processed oat, these changes were nonsignificant. Photo-oxidation of acylated fatty acids may significantly contribute to the development of volatile lipid oxidation products during storage.

Improved management of Avena ludoviciana and Phalaris paradoxa with more densely sown wheat and less herbicide

Abstract: The effectiveness of crop competition for better weed control and reducing herbicide rates was determined for Avena ludoviciana and Phalaris paradoxa. Four experiments, previously broadcast with seeds of the two weeds in separate plots, were sown with three wheat densities, and emerged weeds were treated with four herbicide doses (0-100% of recommended rate). The measured crop and weed traits were first analysed across experiments for treatment effects. Grain yield and weed seed production data were then analysed using cubic smoothing splines to model the response surfaces. Although herbicide rate for both weeds and crop density for P. paradoxa had significant linear effects on yield, there was a significant non-linearity of the response surface. Similarly, herbicide rate and crop density had significant linear effects on weed seed production, and there was significant non-linearity of the response surface that differed for the weed species. Maximum crop yield and reduction in seed production of P. paradoxa was achieved with approximately 80 wheat plants m-2 and weeds treated with 100% herbicide rate. For A. ludoviciana, this was 130 wheat plants m-2 applied with 75% herbicide rate. Alternatively, these benefits were achieved by increasing crop density to 150 plants m-2 applied with 50% herbicide rate. At high crop density, application of the 100% herbicide rate tended to reduce yield, particularly with the A. ludoviciana herbicide, and this impacted adversely on the suppression of weed seed production. Thus, more competitive wheat crops have the potential for improving weed control and reducing herbicide rates.

The effect of fertilizer additions on the solubility and plant-availability of Cd, Ni and Zn in soil

Abstract: We conducted a pot experiment to investigate the effect of fertilizer additions on the solubility of Cd, Ni and Zn in soil solution and their uptake by plants. Radish (Raphanus sativus cv. Crystal Ball), oat (Avena sativa cv. Thule) and water spinach (Ipomoea aquatica cv. Kangkon) were grown in a naturally metal-rich soil. From day 7 after planting, fertilizers were added daily to each pot. Additions of fertilizer nutrients affected the pH of soil and soil solution, soluble and tissue concentrations of Ca, Mg, K, Cd, Ni and Zn differently in three plant species. The trend of soil and solution pH was in the order: water spinach < radish < oats, that resulted highest soluble and plant tissue concentrations of Cd and Zn in the water spinach followed by radish and then oats. However, Ni concentration in the soil solution increased in all pots and was not affected by pH changes. Soil solution pH increased by more than 1unit in the pots with radish and oats, indicating that mechanisms other than acidification, such as ion exchange and root exudation, may be responsible for the increased heavy metal uptake in these two plant species. Paired t-test showed significantly higher uptake of Cd and Zn in the radish plants resulting in lower concentrations of these elements in the solution. The contribution of mass flow to the supply of major cations and heavy metals varied among elements and plant species. Cadmium, Zn and K were taken up rapidly by all plant species in response to the amount supplied by mass flow. In contrast, the supply of Ni was in excess of its uptake by radish and water spinach. The uptake of all elements was positively correlated (p<0.0001) with mass flow and the transpiration rate in individual plant species. The study suggests that fertilizer cations increased the uptake of metals by improving growth conditions, but the magnitude of increase depended on plant species.

Toxicity of methyl tert-butyl ether to plants (Avena sativa, Zea mays, Triticum aestivum, and Lactuca sativa).

Abstract: Influence of methyl tert-butyl ether (MTBE) on the germination of seeds and growth of seedling plants were studied in laboratory experiments. Test plants were wild oats (Avena sativa), sweet corn (Zea mays), wheat (Triticum aestivum), and lettuce (Lactuca sativa). Seed germination, shoot growth, and root growth of plants exposed to different concentrations of MTBE in a moist soil were examined. Seed germination and seedling growth in MTBE-contaminated soil were markedly reduced in all test plants. The median lethal concentration values for seed germination tests and the median effective concentration values for shoot or root growth were calculated. The values for lettuce, wild oats, wheat, and sweet corn were in the range of 18 to 91, 362 to 459, 432 to 751, and 672 to 964 mg MTBE/kg soil as dry weight, respectively. Lettuce was most sensitive to MTBE, followed (in order of decreasing sensitivity) by wild oats, wheat, and sweet corn. Because MTBE can be readily absorbed by plants due to its high solubility in water, plant growth was a more sensitive endpoint than seed germination. Shoot length was more reduced in MTBE-contaminated soil than was the root length, which indicated that MTBE might be transported within the plant from the roots to the shoots.

Sorption of copper, zinc and cobalt by oat and oat products.

Abstract: We determined copper, zinc and cobalt sorption by oat and its products under variable pH conditions as well as the content of neutral dietary fiber (NDF) and its fractional composition. Adsorbents in a model sorption system were: oat, dehulled oat, oats bran and oats flakes. Three various buffers (pH 1.8, 6.6 and 8.7) were used as dispersing solutions. Results collected during this study indicate that copper, zinc and cobalt sorption is significantly affected by the type of cereal raw material. Zinc and copper ions are subjected to higher sorption than cobalt ions. Examined metal ions were subjected to high sorption under conditions corresponding to the duodenum environment (pH 8.7), regardless of the kind of adsorbent. A little lower sorption capacity is observed under conditions close to the neutral environment, while the lowest one is found in environment reflecting conditions of stomach juice (pH 1.8). Zinc ions are bound intensively by dehulled oat, while oats flakes bound mostly copper and cobalt, independently on environmental conditions. Contents of dietary fiber in oat, dehulled oat, oat bran and oat flakes were: 40.1, 19.3, 20.3 and 14.3%, respectively. The dominating fraction in all oat products was the fraction of hemicelluloses. The content of remaining fractions varies in dependence on the product.

Evaluation of groat percentage in oats (avena sativa l.) by near infrared spectroscopy

Abstract: In oats (Avena sativa L.), groat percentage (GP) is defined as the amount of hull-less kernels obtained after de-hulling, expressed as a percentage of the weight of the sample. GP is considered a good marker of milling yield in oats, but so far a quick and reliable method to define it has been lacking. In the present study, a group of oat cultivars, grown in Italy in 1998–2000, was used to develop near infrared (NIR) spectroscopy calibration equations for this parameter. The material for the analysis was represented by whole kernels. The coefficient of determination R 2 c was 0.80. The ability of the equation to predict GP was then verified using a separate set of oat samples. These preliminary results indicated that NIR spectroscopy could be considered a good tool to predict GP in oat cultivars; analysis of whole kernels allowed time to be saved by avoiding the grinding stage in sample preparation.

Response of oat (Avena sativa) to nitrogen and phosphorus levels

Abstract: A field experiment was conducted during the winter seasons of 1996–97 and 1997–98 to study the response of forage oat (Avena sativa L.) to levels of nitrogen and phosphorus. The yield attributes as well as green and dry-forage yields increased significantly up to 50 kg N and 40 kg P2O5/ha. However, crude protein yield and nutrient uptake showed linear response up to 75 and 60 kg/ha N and P2O5 respectively.

The competitive effects of wild oat (avena ludoviciana l.) on winter wheat (triticum aestivum l.) at different densities

Abstract: هديكچ يشحو فلاوي و مدنگ يتباقر تارثا يسررب روظنم هب يـعارز لاـس رد، فـلتخم ياه مكارت رد ٨٠ ‐ ١٣٧٩ تروـص هـب يشـيامزآ كولب حرط بلاق رد ليروتكاف دـشارجا دهشم ردراركت راهچ اب يفداصت لماك ياه . رد مدـنگ مكارـت لماـش شياـمزآ ياـهروتكاف حطس هس ) ٣٠٠ ، ٤٥٠ و ٦٠٠ عبرم رتم رد هتوب ( حطس جنپ رد فلاوي مكارت و ) ،رفص ٢٠ ، ٤٠ ، ٨٠ و ١٦٠ هتوب عـبرم رـتم رد ( دوـب . جياـتن مدنگ زا رتشيب دشر يناياپ لحارم رد ورتمك دشر هيلوا لحارم رد ،مدنگ مكارت هس ره رد يشحو فلاوي عافترا هك داد ناشن شيامزآ دوب . دش مدنگ عافترا شيازفا ببس مدنگ مكارت شيازفا . مـه مدـنگ مكارت شيازفا و گرـب حطـس شهاـك ببـس نيـنچ ساـمويب يشحو فلاوي و گرـب حطس شهاك ببس ،يشحو فلاوي مكارت شيازفا و دـيدرگ مدـنگ ساـمويب . رد يپوناـك ندـش هتسـب ناـمز دودح يشحو فلاوي ١٥ عيرس زور دوب مدنگ زارت . بـيترت هـب دشر هرود لوط رد فلاويو مدنگ يبسن دشر تعرس طسوتم ٠٢٧ / ۰ و ٠٣٤ / ۰ دوب زور رد مرگ رب مرگ . ناد دركلمع شهاك رادقم نيرتشيب دودح مدنگ ه ٤٧ مكارـت رد هـكدوب دص رد ١٦٠ رد فلاوـي هـتوب مكارت ٣٠٠ دش هدهاشم عبرم رتم رد مدنگ هتوب . دوب رتشيب فلاوي روضح زا يشان مدنگدركلمع شهاك ،مدنگ نيياپ ياه مكارترد .