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Peter R Shewry - One of the best experts on this subject based on the ideXlab platform.
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drought stress affects the protein and dietary fiber content of wholemeal wheat flour in wheat aegilops addition lines
PLOS ONE, 2019Co-Authors: Marianna Rakszegi, Marta Molnarlang, Istvan Molnar, Eva Darko, Alison Lovegrove, Laszlo Lang, Zoltan Bedő, Peter R ShewryAbstract:Wild relatives of wheat, such as Aegilops spp. are potential sources of genes conferring tolerance to drought stress. As drought stress affects seed composition, the main goal of the present study was to determine the effects of drought stress on the content and composition of the grain storage protein (gliadin (Gli), glutenin (Glu), unextractable polymeric proteins (UPP%) and dietary fiber (arabinoxylan, β-glucan) components of hexaploid bread wheat (T. aestivum) lines containing added chromosomes from Ae. biuncialis or Ae. geniculata. Both Aegilops parents have higher contents of protein and β-glucan and higher proportions of water-soluble arabinoxylans (determined as Pentosans) than wheat when grown under both well-watered and drought stress conditions. In general, drought stress resulted in increased contents of protein and total Pentosans in the addition lines, while the β-glucan content decreased in many of the addition lines. The differences found between the wheat/Aegilops addition lines and wheat parents under well-watered conditions were also manifested under drought stress conditions: Namely, elevated β-glucan content was found in addition lines containing chromosomes 5Ug, 7Ug and 7Mb, while chromosomes 1Ub and 1Mg affected the proportion of polymeric proteins (determined as Glu/Gli and UPP%, respectively) under both well-watered and drought stress conditions. Furthermore, the addition of chromosome 6Mg decreased the WE-pentosan content under both conditions. The grain composition of the Aegilops accessions was more stable under drought stress than that of wheat, and wheat lines with the added Aegilops chromosomes 2Mg and 5Mg also had more stable grain protein and pentosan contents. The negative effects of drought stress on both the physical and compositional properties of wheat were also reduced by the addition of these. These results suggest that the stability of the grain composition could be improved under drought stress conditions by the intraspecific hybridization of wheat with its wild relatives.
Bernard Cuq - One of the best experts on this subject based on the ideXlab platform.
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Description of Microstructural Changes in Wheat Flour and Flour Components during Hydration by using Environmental Scanning Electron Microscopy
LWT - Food Science and Technology, 2002Co-Authors: Alma Delia Román-gutiérrez, Stéphane Guilbert, Bernard CuqAbstract:Abstract The initial microstructures of two wheat flours (hard wheat flour and soft wheat flour) and flour components (starch, gluten, soluble Pentosans and insoluble Pentosans) were observed by scanning electron microscopy (SEM) and the changes in microstructure during hydration were described using environmental SEM (ESEM). SEM images permitted observation of the classical microstructure of wheat flour particles and starch granules. The initial microstructure of the purified fractions of flour components (gluten, soluble Pentosans and insoluble Pentosans) seemed largely dependent on the purification techniques, and could not thus directly be used to describe their in situ behavior during flour processing. ESEM observations of wheat flours and flour components during hydration first demonstrated slight changes in surface of particles that we associated to apparent swelling effects. The formation of a continuous aqueous phase between particles was observed for long hydration times.
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Distribution of Water between Wheat Flour Components: A Dynamic Water Vapour Adsorption Study
Journal of Cereal Science, 2002Co-Authors: Alma Delia Román-gutiérrez, Stéphane Guilbert, Bernard CuqAbstract:The water adsorption properties of hard and soft wheat flours and flour components (starch, damaged starch, gluten, soluble Pentosans, and insoluble Pentosans) were determined at 25 °C using a controlled atmosphere microbalance. At different levels of relative humidity (from 10% to 95%), changes in sample mass (i.e., water gain) were continuously measured versus time and described using exponential models (R2≥0·994). Water adsorption isotherms were constructed for wheat flours and flour components and described using Guggenheim-Anderson-de Boer models (R2≥0·997). It was not possible to distinguish between the selected hard and soft wheat flours by their isotherms. The water-soluble Pentosans had the highest water adsorption capacity. The theoretical distribution of water between the flour components (calculated using the Guggenheim-Anderson-de Boer parameters) was starch, 88%; gluten, 10%; and Pentosans, 2%.
Marianna Rakszegi - One of the best experts on this subject based on the ideXlab platform.
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drought stress affects the protein and dietary fiber content of wholemeal wheat flour in wheat aegilops addition lines
PLOS ONE, 2019Co-Authors: Marianna Rakszegi, Marta Molnarlang, Istvan Molnar, Eva Darko, Alison Lovegrove, Laszlo Lang, Zoltan Bedő, Peter R ShewryAbstract:Wild relatives of wheat, such as Aegilops spp. are potential sources of genes conferring tolerance to drought stress. As drought stress affects seed composition, the main goal of the present study was to determine the effects of drought stress on the content and composition of the grain storage protein (gliadin (Gli), glutenin (Glu), unextractable polymeric proteins (UPP%) and dietary fiber (arabinoxylan, β-glucan) components of hexaploid bread wheat (T. aestivum) lines containing added chromosomes from Ae. biuncialis or Ae. geniculata. Both Aegilops parents have higher contents of protein and β-glucan and higher proportions of water-soluble arabinoxylans (determined as Pentosans) than wheat when grown under both well-watered and drought stress conditions. In general, drought stress resulted in increased contents of protein and total Pentosans in the addition lines, while the β-glucan content decreased in many of the addition lines. The differences found between the wheat/Aegilops addition lines and wheat parents under well-watered conditions were also manifested under drought stress conditions: Namely, elevated β-glucan content was found in addition lines containing chromosomes 5Ug, 7Ug and 7Mb, while chromosomes 1Ub and 1Mg affected the proportion of polymeric proteins (determined as Glu/Gli and UPP%, respectively) under both well-watered and drought stress conditions. Furthermore, the addition of chromosome 6Mg decreased the WE-pentosan content under both conditions. The grain composition of the Aegilops accessions was more stable under drought stress than that of wheat, and wheat lines with the added Aegilops chromosomes 2Mg and 5Mg also had more stable grain protein and pentosan contents. The negative effects of drought stress on both the physical and compositional properties of wheat were also reduced by the addition of these. These results suggest that the stability of the grain composition could be improved under drought stress conditions by the intraspecific hybridization of wheat with its wild relatives.
Xavier Rouau - One of the best experts on this subject based on the ideXlab platform.
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Large scale isolation of water-soluble and water-insoluble Pentosans from wheat flour
LWT - Food Science and Technology, 1995Co-Authors: Anne-lise Faurot, Luc Saulnier, Serge Bérot, Yves Popineau, Marie-dominique Petit, Xavier Rouau, Jean-françois ThibaultAbstract:Abstract A procedure has been developed which allows the isolation of enriched pentosan fractions from wheat flour. The procedure is based on mixing flour and water (50 kg/150L). After centrifugation the supernatant is heat-treated and then concentrated by cross-flow ultrafiltration to give water-soluble Pentosans, whereas the insoluble residue is treated with Alcalase and then Termamyl to give water-insoluble Pentosans. Starting from 50 kg of flour from three different varieties (Soissons, Thesee, Apollo), water-soluble and water-insoluble Pentosans containing respectively 100–200 g of water-soluble and 250–350 g of water-insoluble arabinoxylans, were prepared within 2 d. Water-soluble Pentosans are constituted of approx. 40% arabinoxylans and are contaminated by proteins, whereas water-insoluble Pentosans are composed of arabinoxylans (ca. 30%) and are contaminated by residual starch (ca 40%). Enrichment factors in arabinoxylans ranged from 98 to 66 for water-soluble and 27 to 19 for water-insoluble Pentosans as compared with initial flour.
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A rapid semi-automated method for the determination of total and water-extractable Pentosans in wheat flours
Carbohydrate Polymers, 1994Co-Authors: Xavier Rouau, Anne SurgetAbstract:A rapid, semi-automated method for the determination of total and water-extractable Pentosans in wheat flours is described. Total Pentosans are solubilized by hot dilute acid within 10 min, and water-extractable Pentosans by aqueous treatment within 15 min. The solubilization/extraction steps have been optimized with respect to accuracy (weighing of large amounts of sample), rapidity and yield of Pentosans. The extracts are analyzed for pentose content by an automated adaptation of the phloroglucinol method of Douglas, on a continuous flow analyzer. The circuit allows the continuous generation of unstable phloroglucinol/acid reagent. The rate of analysis has been fixed at 40 samples h−1. The pentosan content of 15 flour samples (total and water-extractable Pentosans, in duplicate extractions), that is, 60 colorimetric determinations, may be carried out in one day by a single trained operator. The method is rapid, sensitive and reproducible (CV% < 3) and correlates well with other methods of pentosan determination. No interference has been found from the major components of wheat flours (starch, gluten). On the other hand, the presence of high levels of some sugars, possibly encountered in cereal-based products, can result in an underestimation (fructose, sucrose) or an overestimation (uronic acids) of the pentosan concentration.
W. Bushuk - One of the best experts on this subject based on the ideXlab platform.
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Effect of added Pentosans on some properties of wheat bread
Food Chemistry, 1992Co-Authors: J. Michniewicz, G.g. Biliaderis, W. BushukAbstract:Abstract The effects of water-soluble (WS-W) and water-insoluble (WI-W) wheat Pentosans and water-soluble (WS-R) rye Pentosans on some baking characteristics of wheat flour and staling of bread were examined. All three pentosan preparations markedly increased the farinograph water absorption. While addition of WS-W and WS-R (at 2%, w/w) Pentosans increased the specific loaf volume, WI-W did not significantly affect this parameter. At a constant dough consistency, pentosan-supplemented breads had higher moisture contents and water activity values. Higher retrogradation rates of the amylopectin, as measured by differential scanning calorimetry, were shown for breads supplemented with Pentosans, presumably due to their higher moisture content. Water-soluble Pentosans retarded the aggreation process between amylose molecules, as evidenced by the amount and type of water-extractable carbohydrates from bread crumb. Susceptibility of bread crumb to pancreatic α-amylase slightly decreased with the addition of Pentosans, particularly upon storage; WI-W was the most effective in this respect.
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Physical Properties of Water-Soluble Pentosans from Different Wheat Varieties'
Cereal Chemistry, 1991Co-Authors: M. S. Izydorczyk, Costas G. Biliaderis, W. BushukAbstract:Cereal Chem. 68(2): 145-150 The physical properties of water-soluble Pentosans and their assessed by the storage modulus (G') and tan6 (G"/G'), were obtained constituents, arabinoxylan and arabinogalactan, in solution or gels, were for the preparations derived from Katepwa, followed by those from HY investigated using purified preparations from flours of eight wheat 355, HY 320, and Fielder. Relatively weak gels were obtained for Pentosans varieties: HY 355, HY 320, Oslo (Canada prairie spring), Glenlea (Canada from Oslo, Marshall, Norstar, and Glenlea. The storage modulus of utility), Fielder (Canada western soft spring), Norstar (Canada western arabinoxylan and pentosan gels (2%, w/v) were positively correlated with hard red winter), Katepwa (Canada western red spring), and Marshall the intrinsic viscosity of the polymers (r = 0.85 and r = 0.83, respectively; (a hard red spring variety unregistered in Canada). The intrinsic viscosities P < 0.01). Cross-linked Pentosans and arabinoxylans held up to 100 for arabinoxylans and arabinogalactans ranged between had ranges of g of water per gram of carbohydrate. Although both arabinoxylans and 2.82-4.20 dl/g and 0.045-0.062 dl/g, respectively. Oxidative gelation of arabinogalactans reduced the surface tension of water, only arabinoxylans 2% (w/v) pentosan and arabinoxylan solutions (H 2 02 and peroxidase) effectively stabilized protein foams on heating. was probed by dynamic rheometry. The most rigid gel networks, as Water-soluble Pentosans of wheat exhibit some unique physical properties that have been the subject of many studies. The ability to bind large quantities of water (Bushuk 1966) and to form viscous solutions or gels via covalent cross-linking (Geissmann and Neukom 1973), are important attributes that also can have direct functional implications during mixing, dough development, and baking of bread. Although the water absorption properties of native Pentosans have been reported in previous investigations (Jelaca and Hlynka 1971, Patil et al 1975), no studies have been done on water absorption of isolated cross-linked Pentosans and their polymeric constituents. The water-holding capacity of polymerized Pentosans probably would affect the distribution of moisture among dough constituents and thereby alter the rheological properties of dough systems. Of the many reports on different aspects of gelation of wheat Pentosans (Neukom and Markwalder 1978, Hoseney and Faubion 1981, Crowe and Rasper 1988, Izydorczyk et al 1990), only one (Ciacco and D'Appolonia 1982) suggested that the gelling ability of Pentosans depends also on their varietal origin. Another important functional property of fermented dough systems is their ability to hold gas. In fact, air occlusion during the mixing and formation of gas cells during fermentation plays an important role in the rheology of dough and consequently affects the final texture of baked products (MacRitchie 1986). In this respect, dough and bread can be viewed as examples of classic foams. The stability of these systems relates to how gas cells resist rupture on baking, especially during the initial oven heating and before the surrounding fluid network (the viscosity of dough at 600C is only one fifth of its viscosity at 25°C) is transformed into a solid structure. This stability depends on the initial gas distribution, and, most important, on the nature of the compounds stabilizing the film around gas cells. Although the involvement of gluten proteins in film formation is generally acknowledged, evidence also indicates that some polysaccharides, such as xanthan, locust bean, and guar gums possess similar properties (Hoseney 1984, McCleary 1986). This article presents information on the gelling potential and flow behavior of purified Pentosans and their constituents in aqueous solutions, as probed by small-deformation mechanical measurements and steady shear rheometry. Furthermore, the surface properties of these polysaccharides are examined in the context of imparting stability to heated foam systems.