Progress 06/09/10 to 06/08/15
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to improve the quality of high soluble fiber oat cultivars. Specific objectives for the project period: Optimize methodologies for the extraction and analysis of soluble oat fiber components; determine environmental variation in the quantity and quality of �-glucan as characterized in the first objective in newly developed high �-glucan cultivars and other oat cultivars; and determine relationships between oil concentration and �-glucan concentration in segregating crosses for these traits, as to how each affects groat breakage during dehulling. Approach (from AD-416): Health benefits derived in humans from the consumption of oats are currently understood to be related to the molecular weight of the soluble fiber component commonly called beta-glucan and the increased viscosity of the gut contents created by high molecular weight beta-glucan. We will develop optimized methodologies for the extraction of beta-glucan in order to evaluate its physical and structural, molecular weight, and viscometric properties. We will collect oats samples, including those from newly developed high soluble fiber cultivars, from replicated plots grown in diverse environments over several years. Then we will use our newly developed methods for the analysis of soluble fiber quality to determine how environment might affect the quality and concentration of beta-glucan, especially in the newly developed high beta-glucan cultivars. Finally, we will test how beta-glucan affects the milling quality of oats. Because beta-glucan is in the cell walls of oats, it is thought to provide a strengthening effect, which reduces groat breakage during dehulling. However, high oil in oats also seems to prevent groat breakage, and currently breeders have been unable to separate the traits of high oil and high beta-glucan in oats. A collaborating genetics program has developed populations of recombinant inbred lines from oat crosses designed to be segregating for high oil and high beta-glucan. We will evaluate the phenotypes of these lines and test their behavior during dehulling to determine the relative roles of oil and beta-glucan in preventing groat breakage during oat milling. The nutritional composition of eighteen oat varieties that had been grown in six different environments were determined in order to show how oat nutritional composition can vary among cultivars and environment. On average, oats contained 56.5% starch, 18.1 % protein, 7.9% oil, 6.0% insoluble fiber, 5.2% soluble fiber, and 1.9% ash. Analysis of mineral concentrations indicated 3,420 ppm potassium, 1, 420 ppm magnesium, 441 ppm calcium, 52 ppm iron, 26 ppm zinc and 0.38 ppm selenium. Wet environments tended to have more starch and soluble fiber, whereas dry environments tended to accumulate more protein relative to other compositional components. The data set provides a more complete account for the variation in oat composition in commonly grown North American oat cultivars than previously available. This is the final report for project #5442-21440-006-00D as the primary investigator has retired.
Impacts
(N/A)
Publications
- Doehlert, D.C., Simsek, S., Thavarajah, D., Thavarajah, P., Ohm, J.-B. 2013. Detailed composition analyses of diverse oat genotype kernels grown in different environments in North Dakota. Cereal Chemistry. 90(6):572-578.
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Progress 10/01/12 to 09/30/13
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to improve the quality of high soluble fiber oat cultivars. Specific objectives for the project period: Optimize methodologies for the extraction and analysis of soluble oat fiber components; determine environmental variation in the quantity and quality of �-glucan as characterized in the first objective in newly developed high �-glucan cultivars and other oat cultivars; and determine relationships between oil concentration and �-glucan concentration in segregating crosses for these traits, as to how each affects groat breakage during dehulling. Approach (from AD-416): Health benefits derived in humans from the consumption of oats are currently understood to be related to the molecular weight of the soluble fiber component commonly called beta-glucan and the increased viscosity of the gut contents created by high molecular weight beta-glucan. We will develop optimized methodologies for the extraction of beta-glucan in order to evaluate its physical and structural, molecular weight, and viscometric properties. We will collect oats samples, including those from newly developed high soluble fiber cultivars, from replicated plots grown in diverse environments over several years. Then we will use our newly developed methods for the analysis of soluble fiber quality to determine how environment might affect the quality and concentration of beta-glucan, especially in the newly developed high beta-glucan cultivars. Finally, we will test how beta-glucan affects the milling quality of oats. Because beta-glucan is in the cell walls of oats, it is thought to provide a strengthening effect, which reduces groat breakage during dehulling. However, high oil in oats also seems to prevent groat breakage, and currently breeders have been unable to separate the traits of high oil and high beta-glucan in oats. A collaborating genetics program has developed populations of recombinant inbred lines from oat crosses designed to be segregating for high oil and high beta-glucan. We will evaluate the phenotypes of these lines and test their behavior during dehulling to determine the relative roles of oil and beta-glucan in preventing groat breakage during oat milling. Oats (Avena sativa L.) contain a soluble fiber commonly called beta glucan to which health benefits have been attributed. Effects of oat plant genotype and environment on beta glucan extractability, flour slurry viscosity, and beta glucan polymer fine structure were investigated. Environment had a strong effect on beta glucan extractability, whereas genotype had no significant effect. However, oats grown in drier environments and cultivars with higher beta glucan content have beta glucan with fine structure differences (relative to oats grown in wetter environments or with lower beta glucan content) that influence extractability of beta glucan. The observed variations may influence functional properties, such as viscosity or potential health benefits. Extraction protocols for beta glucan from oat flour were tested to determine optimal conditions for beta glucan quality testing, which included extractability and molecular weight. Mass yields of beta glucan were constant at all temperatures, pH values, and flour-to-water ratios, as long as sufficient time and enough repeat extractions were performed and no hydrolytic enzymes were present. Extracts contained about 30�60% beta glucan, with lower proportions associated with higher extraction temperatures in which more starch and protein were extracted. All commercial starch hydrolytic enzymes tested, even those that are considered homogeneous, degraded apparent molecular weight of beta glucan as evaluated by size exclusion chromatography. Higher concentration beta glucan solutions could be prepared by controlling the flour-to-water ratio in extractions. Optimal conditions were determined that generated the highest native beta glucan concentrations.
Impacts
(N/A)
Publications
- Doehlert, D.C., Simsek, S. 2012. Variation in beta-glucan fine structure, extractability, and flour slurry viscosity in oats due to genotype and environment. Cereal Chemistry. 89:242-246.
- Doehlert, D.C., Simsek, S., Mcmullen, M.S. 2012. Extraction of beta-glucan from oats for soluble dietary fiber quality analysis. Cereal Chemistry. 89:230-236.
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Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to improve the quality of high soluble fiber oat cultivars. Specific objectives for the project period: Optimize methodologies for the extraction and analysis of soluble oat fiber components; determine environmental variation in the quantity and quality of �-glucan as characterized in the first objective in newly developed high �-glucan cultivars and other oat cultivars; and determine relationships between oil concentration and �-glucan concentration in segregating crosses for these traits, as to how each affects groat breakage during dehulling. Approach (from AD-416): Health benefits derived in humans from the consumption of oats are currently understood to be related to the molecular weight of the soluble fiber component commonly called beta-glucan and the increased viscosity of the gut contents created by high molecular weight beta-glucan. We will develop optimized methodologies for the extraction of beta-glucan in order to evaluate its physical and structural, molecular weight, and viscometric properties. We will collect oats samples, including those from newly developed high soluble fiber cultivars, from replicated plots grown in diverse environments over several years. Then we will use our newly developed methods for the analysis of soluble fiber quality to determine how environment might affect the quality and concentration of beta-glucan, especially in the newly developed high beta-glucan cultivars. Finally, we will test how beta-glucan affects the milling quality of oats. Because beta-glucan is in the cell walls of oats, it is thought to provide a strengthening effect, which reduces groat breakage during dehulling. However, high oil in oats also seems to prevent groat breakage, and currently breeders have been unable to separate the traits of high oil and high beta-glucan in oats. A collaborating genetics program has developed populations of recombinant inbred lines from oat crosses designed to be segregating for high oil and high beta-glucan. We will evaluate the phenotypes of these lines and test their behavior during dehulling to determine the relative roles of oil and beta-glucan in preventing groat breakage during oat milling. Recent emphasis of this program has been on development of protocols for rheological analyses of beta-glucan extracts and analysis of treatments on rheological properties on beta-glucan. In particular, effects of hydrothermal treatments on groats, effects of drying of isolated beta- glucan, and the effect of growth environment of rheological properties of isolated beta-glucan have been emphasized. Measurements include apparent viscosity in flour slurries with a spindle viscometer, intrinsic viscosity in soluble extracts using an Ubbelohde-type capillary viscometer, and shear viscosity analysis with a cone and plate rotational rheometer. Efforts continue to determine effects of environment on beta- glucan properties and to determine the basis for resistance to groat breakage during dehulling. Accomplishments 01 Effects of hydrothermal treatments on oat soluble fiber viscosity. High viscosity generated by oat soluble fiber in the gut is necessary for the health benefits attributed to oats in the diet. An ARS scientist in Farg North Dakota, in collaboration with university scientists from Fargo, North Dakota and Ames, Iowa, have determined that hydrothermal treatment like steaming and toasting change the viscosity of oat soluble fiber. Steaming appears to make the fiber molecule stretch out where it entangl more with other fiber molecules, which enhances the viscosity. Toasting seems to make the fiber molecule fold up on itself, entangle less with adjacent polymers, and generates less viscosity. Results suggest steam treatments may enhance health benefits of oat soluble fiber. 02 A simple laboratory test for Fusarium Head Blight resistance in wheat. Fusarium Head Blight is a common plant fungal disease affecting wheat, barley, and oats that has caused billions of dollars of crop losses over the past decade. An ARS scientist in Fargo, North Dakota, in collaborati with scientists at North Dakota State University, has developed a simple laboratory method to test for resistance to this disease in wheat cultivars that involves growing the fungus in the laboratory on gels containing bran from wheat genotypes being selected for resistance properties. Fungal growth is lower in cultures containing bran of wheat genotypes more resistant to Fusarium infection. The method is cheaper an simpler than tests currently used to test for Fusarium resistance and ma accelerate development of Fusarium resistant cultivars.
Impacts
(N/A)
Publications
- Doehlert, D.C., Rayas-Duarte, P., Mccullen, M.S. 2011. Inhibition of Fusarium graminiarum growth in flour gel cultures by hexane soluble compounds from oat (Avena sativa L.) flour. Journal of Food Protection. 74(12):2188-2191.
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) The overall goal of this project is to improve the quality of high soluble fiber oat cultivars. Specific objectives for the project period: Optimize methodologies for the extraction and analysis of soluble oat fiber components; determine environmental variation in the quantity and quality of �-glucan as characterized in the first objective in newly developed high �-glucan cultivars and other oat cultivars; and determine relationships between oil concentration and �-glucan concentration in segregating crosses for these traits, as to how each affects groat breakage during dehulling. Approach (from AD-416) Health benefits derived in humans from the consumption of oats are currently understood to be related to the molecular weight of the soluble fiber component commonly called beta-glucan and the increased viscosity of the gut contents created by high molecular weight beta-glucan. We will develop optimized methodologies for the extraction of beta-glucan in order to evaluate its physical and structural, molecular weight, and viscometric properties. We will collect oats samples, including those from newly developed high soluble fiber cultivars, from replicated plots grown in diverse environments over several years. Then we will use our newly developed methods for the analysis of soluble fiber quality to determine how environment might affect the quality and concentration of beta-glucan, especially in the newly developed high beta-glucan cultivars. Finally, we will test how beta-glucan affects the milling quality of oats. Because beta-glucan is in the cell walls of oats, it is thought to provide a strengthening effect, which reduces groat breakage during dehulling. However, high oil in oats also seems to prevent groat breakage, and currently breeders have been unable to separate the traits of high oil and high beta-glucan in oats. A collaborating genetics program has developed populations of recombinant inbred lines from oat crosses designed to be segregating for high oil and high beta-glucan. We will evaluate the phenotypes of these lines and test their behavior during dehulling to determine the relative roles of oil and beta-glucan in preventing groat breakage during oat milling. A new project on the characterization of beta-glucan quality in oats was initiated. Initial experiments centered on the optimization of beta- glucan extraction for analytical purposes. The simplest approaches have proved to be the best. We found that temperature and pH had very little effect on beta-glucan extraction, as long as sufficient time was allowed for the extraction (e.g. 18 hrs) and that enzymes had been sufficiently inactivated in the flour. Addition of external hydrolytic enzymes to digest possible contaminants invariably led to the degradation of beta- glucan polymer. Flour to water ratio of 2 g of flour to 50 mL proved best for extraction of beta-glucan for analytical purposes. For viscosity experiments, we found 8 g of flour per 50 mL water provided solutions saturated with high molecular weight beta-glucan. Addition of hydrolytic enzymes or insufficient inactivation of endogenous hydrolytic enzymes led to more efficient extraction, but solutions contained polymers with much lower molecular weights. Because high molecular weight and high viscosity are considered positive quality characteristics, our simple extraction appeared best suited for analysis of beta-glucan quality. The most effective methods for enzyme inactivation appeared to involve high temperature steam (106 to 130 degrees C). Viscosity experiments along with molecular weight determinations using multi angle laser light scattering indicated that steam treatments changed the configuration of the beta-glucan relative to dry heat treatments. Steam heat increased intrinsic viscosity of solutions relative to toasted samples (dry heat) without affecting the molecular weight of the polymer. We have also determined significant differences in extractability of beta-glucan and in the fine structure of polymer according to genotype and environment. Accomplishments 01 Standardized extraction of beta-glucan. Beta-glucan is a soluble fiber i oats that improves heart health in humans by decreasing serum cholestero Since the development of high beta-glucan oat cultivars, the quality of the beta-glucan derived from cultivars grown in different locations and environments has come into question. ARS Researchers in Fargo, ND, developed a standardized extraction protocol for quality analyses for be glucan. They demonstrated the importance of hydrothermal treatments for the inactivation of endogenous beta-glucanase activity and that external applied hydrolytic enzymes, designed to hydrolyze contaminating compound extracted with the beta-glucan, also degraded beta-glucan. The simple water extraction of oat flour from grain exposed to 106 degrees C steam provides a means to evaluate the quality of beta-glucan from any oat gra This provides standardized protocols for industry to evaluate beta- glucan quality in oat lots. 02 Environment affects beta-glucan. A major reason that people eat oats is because the soluble fiber or beta-glucan in oats will lower cholesterol and improve heart health. ARS Researchers in Fargo, ND, in collaboration with North Dakota State University, have developed oat cultivars high in beta-glucan, but it has never been clear how environment affects the bet glucan. Recent results from Fargo ARS and North Dakota State University laboratories have shown that drier environments produce oats with lower beta-glucan concentration and that the molecular structure of the beta- glucan has been changed in subtle ways. This information will help oat companies source their oats more appropriately to their needs.
Impacts
(N/A)
Publications
- Doehlert, D.C., Angelikousis, S., Vick, B.A. 2010. Accumulation of Oxygenated Fatty Acids in Oat Lipids During Storage. Cereal Chemistry. 87(6):532�537.
- Doehlert, D.C., Moreau, R.A., Welti, R., Roth, M.R., Mcmullen, M.S. 2010. Polar lipids from oat kernels. Cereal Chemistry. 87(5):467-474.
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