bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Germination and Water Content on the Microstructure and Rheological Properties of Two Rye Doughs
Authors: Autio K. , Fabritius M. , Kinnunen A. 
Published: June 2007

ABSTRACTTwo rye cultivars, Marder and Motto, with falling numbers 314 and 309, respectively, were germinated in vitro. Relative to the native grains, germination induced minor local changes in the microstructure of cell walls and proteins in the kernels. Kernels of germinated and native grains were milled, and doughs were prepared from the flours, with water content and incubation time varied according to experimental design. The viscoelastic properties of the doughs were measured just after mixing and after various incubation times. The area of blue fluorescence, a measure of intact cell walls, was quantified by computer‐assisted image analysis in thin sections of rye dough after mixing and incubation, and the starch structure was studied under the microscope after iodine staining. The water content of the doughs was explained well by the rheological behavior. Doughs made from flours of germinated grains were always softer than doughs made from flours of native grains, and Marder doughs were always more rigid than Motto doughs. The higher the water content, and the longer the incubation time, the greater the rheological changes during incubation. Microstructural studies showed that germination and incubation caused changes in the cell wall structures of dough that might explain the softening of the doughs.
Relating Rice Milling Quality Changes During Adsorption to Individual Kernel Moisture Content Distribution
Authors: Siebenmorgen T. J. , Perdon A. A. , Chen X. , Mauromoustakos A. 
Published: June 2007

ABSTRACTSeveral varieties of rough rice that were either stored for an extended period of time or freshly harvested were conditioned to initial moisture contents ranging from 10 to 17%. After the individual kernel moisture content distributions were measured, the samples were soaked in water at temperatures ranging from 10 to 40°C. The samples were then dried and milled. The bulk critical moisture content, at which head rice yield began to decline due to moisture adsorption, ranged from 12.5 to 14.9%, depending on the variety, harvest moisture content, and storage conditions. The kernel critical moisture content, determined from each sample from the cumulative kernel moisture content frequency distribution, increased with increasing sample initial moisture content.
Automated Color Classification of Single Wheat Kernels Using Visible and Near‐Infrared Reflectance
Authors: Dowell F. E. 
Published: June 2007

ABSTRACTModification of an existing single kernel wheat characterization system allowed collection of visible and near‐infrared (NIR) reflectance spectra (450–1,688 nm) at a rate of 1 kernel/4 sec. The spectral information was used to classify red and white wheats in an attempt to remove subjectivity from class determinations. Calibration, validation, and prediction results showed that calibrations using partial least squares regression and derived from the full wavelength profile correctly classed more kernels than either the visible region (450–700 nm) or the NIR region (700–1,688 nm). Most results showed >99% correct classification for single kernels when using the visible and NIR regions. Averaging of single kernel classifications resulted in 100% correct classification of bulk samples.
Identification and Characterization of U.S. Wheats Carrying Null Alleles at the wx Loci
Authors: Graybosch R. A. , Peterson C. J. , Hansen L. E. , Rahman S. , Hill A. , Skerritt J. H. 
Published: June 2007

ABSTRACTGranule‐bound starch synthase (GBSS) is the primary enzyme responsible for the synthesis of amylose in amyloplasts of cereal endosperm cells. Bread wheats, due to their hexaploid genetic system, carry three genes (wx loci) encoding GBSS. Purification and separation of GBSS from more than 200 North American hexaploid wheats allowed the identification of genotypes that carry null alleles at either the wx‐A1 and wx‐B1 loci. In addition, the cultivar Ike carried both wx‐A1 and wx‐B1 null alleles. No wx‐D1 nulls were detected. Null alleles were found in 10% of the hard winter wheats tested, but in only 2% of the sampled soft winter wheats. Amylose contents of wheats carrying single null alleles at either the wx‐A1 or wx‐B1 loci often were lower than those of wild type wheats, but greater reduction in amylose content was observed in Ike. Monoclonal antibodies were used to quantify water‐extractable GBSS in both wild‐type and null genotypes. Gene dosage compensation was evident, although GBSS content, as measured by ELISA, was significantly lower in Ike than in all other wheats. The identification of null alleles in adapted genotypes suggests the development of wheats with a wide range of amylose contents will be possible by simple genetic crossing and selection.
Effect of Additional Separation and Grinding on the Chemical and Physical Properties of Selected Corn Dry‐Milled Streams
Authors: Jamin Fen F. , Flores Rolando A. 
Published: June 2007

ABSTRACTThree streams of corn dry‐milled products (corn grits, corn cones, and corn flour) from three different commercial corn dry‐millers were further separated by particle size according to the major portion of each stream. They were separated into corn grits (1.190 and 0.841 mm), corn cones (0.595, 0.420, and 0.297 mm), and corn flour (0.297 and 0.210 mm). Besides separation, corn grits were also ground and then separated into ground corn grits (0.297 and 0.210 mm). The original streams, streams with additional separation, and streams with additional grinding were analyzed for protein content, ash content, crude fat content, and color properties. Duncan's significant difference tests (P < 0.01) showed that additional separation and grinding of the commercial corn grits, corn cones, and corn flour affected protein, crude fat content, and color parameter (L, a, and b) distribution of the products. The tristimulus parameters (L, a, and b) were good indicators of the protein content of the corn dry‐milled streams studied.
Method for Determining the Rate and Extent of Accelerated Starch Retrogradation
Authors: Jacobson Mark R. , BeMiller James N. 
Published: June 2007

ABSTRACTA method to accelerate and quantitate retrogradation of starch pastes using a freeze‐thaw cycle (FTC) process and turbidometric analysis has been developed. Using this method and differential scanning calorimetry (DSC), it was determined that the rate of retrogradation in 2.5% waxy maize pastes was inversely correlated to the rate of freezing, and that the thawing temperature affected perfection of the crystallites in retrograded amylopectin. DSC and X‐ray diffraction were used to determine whether the crystallites formed during the FTC process were the same as those formed in starch pastes held isothermally at 4°C. Analysis of retrogradation of pastes of starches from various botanical sources indicated that the method reflects retrogradation in higher concentration pastes. Retrogradation rates were reduced by the addition of sodium dodecyl sulfate. Microstructures of freeze‐thaw processed waxy maize and common corn starch pastes were examined.
Heat‐Shock Protein 70 and Dough‐Quality Changes Resulting from Heat Stress During Grain Filling in Wheat
Authors: Blumenthal C. , Stone P. J. , Gras P. W. , Bekes F. , Clarke B. , Barlow E. W. R. , Appels R. , Wrigley C. W. 
Published: June 2007

ABSTRACTIn an attempt to further elucidate the molecular mechanisms that determine the loss of dough strength associated with heat stress of growing wheat, the roles of heat‐shock proteins (HSP) and heat‐shock elements upstream of glutenin genes were investigated. A range of genotypes differed in the extent of synthesis of high molecular weight glutenin subunits (HMW‐GS) and HSP during heat stress. The concentration of HSP 70 remaining in mature grain increased as a result of a few days' heat stress of wheat plants. The amount of HSP 70 in mature grain samples from heat‐stressed plants of 45 genotypes was not strongly correlated with loss of dough strength. There was much less evidence for this mechanism than for other molecular hypotheses from the literature, particularly, changes in glutenin‐to‐gliadin ratio, size distribution of the glutenin polymer, and the involvement of HSP and chaperones during grain‐protein synthesis. HSP 70 was purified from heat‐stressed grain, and was added to (or incorporated into) dough in the direct‐drive mixograph. The HSP behaved similarly to several other hydrophilic proteins when added at a level of 2 mg/2 g of flour. It showed no dramatic effects on dough properties that could constitute a major explanation for the dough‐weakening effects of heat stress, even though the level of addition was well above the maximum levels that might be encountered in field‐grown, mature grain. Furthermore, sequencing of the genes (upstream of the coding region) for HMW‐GS failed to show the presence of heat‐shock promoters, even for genotypes that differed considerably in their reactions to heat stress. The findings simplify the range of possibilities that cause heat‐related loss of dough strength, focusing attention on the degree of polymerization of the glutenin chains, and on the roles of HSP and chaperones in the developing grain.
Purification and Characterization of a Hexose Oxidase with Excellent Strengthening Effects in Bread
Authors: Poulsen Charlotte , H⊘strup Pernille Bak 
Published: June 2007

ABSTRACTHexose oxidase (EC 1.1.3.5) (HOX) was purified 51‐fold from the red algae Chondrus crispus, by several chromatography methods, including hydrophobic interaction, chelating Sepharose, anion exchange, gel filtration, and chromatofocusing. Purified HOX was subjected to native PAGE and activity staining with nitroblue tetrazolium. For HOX electroeluted out of the gel and digested with endoproteinase Lys‐C, the internal peptide sequence determined was: D‐P‐G‐Y‐I‐V‐I‐D‐V‐N‐A‐G‐T‐(V or P)‐D‐K‐P‐D‐P‐X. The molecular mass, determined by gel filtration, was 126 kDa, versus 65 kDa determined by SDS‐PAGE. The pI was determined to 4.64 and 4.79 as a double band on an isoelectrofocusing gel. Km was determined to 2.7 mM for D‐glucose, 3.6 mM for D‐galactose, 20.2 mM for cellobiose, 43.7 mM for maltose, 90.3 mM for lactose, 102 mM for xylose, and 531 mM for arabinose. The oxidation of thiol groups in gluten was determined by using Ellman's reagent: 5,5′‐dithiobis (2‐nitrobenzoic acid). The effect of HOX was compared to that of glucose oxidase. Both enzymes caused a dose‐responsive reduction in the free thiol groups. Extensigraph measurements and baking tests confirmed that HOX caused increased dough strength and increased bread volume more efficiently than glucose oxidase used in the same dosage.
Effect of Mixing Conditions on the Behavior of Lipoxygenase, Peroxidase, and Catalase in Wheat Flour Doughs
Authors: Delcros Jean‐François , Rakotozafy Lalatiana , Boussard Aline , Davidou Sylvie , Porte Catherine , Potus Jacques , Nicolas Jacques 
Published: June 2007

ABSTRACTThe effect of mixing has been tested on the extractable activities of lipoxygenase, peroxidase, and catalase from dough after 2, 5, and 20 min of mixing, and 30 min of rest period after 20 min of mixing. Different mixing conditions have been studied including temperature, atmosphere, speed, amount of water added to the dough, buffer solutions between pH 3.6 and 7.5 added to the dough, and different additives (linoleic acid, guaiacol, hydrogen peroxide, ascorbic acid, cysteine, yeast, and sodium chloride). In all the mixing conditions tested, the dough peroxidase activity remains equivalent to the initial flour activity, whereas losses in lipoxygenase and catalase activities largely varied according to mixing conditions. The results show that a self‐destruction mechanism as well as physicochemical denaturation are responsible for these losses. Lipoxygenase losses seem mainly associated with the former mechanism, whereas catalase losses are highly increased in acidic conditions (physicochemical denaturation). Therefore, the relative impact of the three oxidoreducing enzymes may be largely modulated by mixing conditions.
Freeze‐Thaw Stability of Amaranth Starch and the Effects of Salt and Sugars
Authors: Baker L. A. , Rayas‐Duarte P. 
Published: June 2007

ABSTRACTFreeze‐thaw stability of amaranth, corn, wheat, and rice starches was determined measuring the percent of syneresis by centrifugation. Thermal properties were calculated by differential scanning calorimetry (DSC). The effects of salt (NaCl at 2 and 5%) and sugars (sucrose, glucose, and fructose at 10, 20, and 30%) on the freeze‐thaw stability of amaranth starch were also studied. Based on DSC and centrifugation methods, amaranth starch had better stability after freezing and thawing through four cycles than did corn, wheat, and rice starches. Amaranth starch with added salt showed similar stability as compared with a control when measured by centrifugation and showed increased stability when measured by DSC. Adding sugars to amaranth starch gels had varying results, but for the most part, they showed similar or increased stability when compared with a control.
Retrogradation of Amaranth Starch at Different Storage Temperatures and the Effects of Salt and Sugars
Authors: Baker L. A. , Rayas‐Duarte P. 
Published: June 2007

ABSTRACTThe retrogradation of amaranth, corn, wheat, and rice starches at different storage temperatures (‐20, 4, and 25°C) was measured by differential scanning calorimetry (DSC). Sodium chloride (2 and 5%), glucose, sucrose, and fructose (10, 20, and 30%) were added to amaranth starch gels. The retrogradation was measured as the percent of gelatinization enthalpy (ΔH
g) of the retrograded gel when compared to the original nonretrograded sample. The data were analyzed fitting an exponential first‐order equation by regression, assuming a first‐order process. A modified equation was used for the data that showed several days of lag time before retrogradation was observed. Retrogradation percentage of amaranth gels at all three storage temperatures was lower than those of corn, wheat, or rice starches. Amaranth starch showed ≈2–9 times slower retrogradation rates than corn, wheat, and rice starches at 4 and ‐20°C, and up to ≈2.8 times lower maximum percent of retrogradation than the other starches at all three temperatures. After 21 days, amaranth, corn, and wheat starches exhibited the highest retrogradation (45, 77, and 67%, respectively) at 4°C, compared to 25 and ‐20°C. Rice starch had a higher retrogradation percentage (55%) at ‐20°C, compared to 25 and 4°C. The percent of retrogradation of gels with 5% NaCl addition decreased ≈2 and 1.7 times at 25 and 4°C, respectively, and increased ≈1.2 times at ‐20°C, compared to the control. The addition of sugars had similar effects in reducing retrogradation at 25 and 4°C and increasing retrogradation at ‐20°C when compared to samples with no sugar added.
Physical Properties of Extruded Wheat Starch‐Additive Mixtures
Authors: Singh N. , Cairns P. , Morris V. J. , Smith A. C. 
Published: June 2007

ABSTRACTThe effects of the addition of fatty acids, monoglycerides (MG), and wheat germ oil (WGO) on the level of crystallinity and the crystalline structure of extrusion‐cooked wheat starch have been studied using twin‐screw extruders. Measurements of water solubility and water absorption indices were made on the extrudates, together with specific mechanical energy (SME) consumption and die pressure for the extruder. MG and the fatty acids added to a level of 4% caused an increase in Vhydrate type crystallinity. WGO addition to a level of 8% caused no change in crystallinity, although the Ehydrate type was favored at lower moisture contents. All additives caused a decrease in SME and an increase or maximum in die pressure. WGO behaved differently than MG and fatty acids in that its addition caused the water solubility index and expansion to increase, as previously observed for other oils added to flours.
Effect of Extrusion Process Parameters on the Quality of Buckwheat Flour Mixes
Authors: Rayas‐Duarte P. , Majewska K. , Doetkott C. 
Published: June 2007

ABSTRACTA response surface analysis using a second‐order central composite design was used to study the effect of extrusion process parameters on the extrudate quality of three blends containing buckwheat flour. The extrudates were prepared as three blends. Blend 1 was a 55:40:5 (w/w) mix of light buckwheat flour, wheat flour, and nonfat dry milk (NFDM). Blend 2 was a 40:55:5 mix of light buckwheat flour, corn meal, and NFDM. Blend 3 was a 30:60:10 mix of light buckwheat flour, corn meal, and NFDM. The blends were processed in a twin‐screw extruder with factorial combinations of the parameters including: process temperatures of 95–150°C, dough moisture of 15–22%, and screw speeds of 260–390 rpm. The linear components alone significantly explained most of the variation of expansion index, bulk density, water absorption, and breaking strength. The greatest amount of variability was explained by process temperature for blend 1. Dough moisture accounted for the greatest amount of variation for blends 2 and 3. Maximum predicted expansion index values and high water absorption percentages were obtained at low dough moisture levels. Dough moisture and process temperatures were the most important factors predicting bulk density. Sensory evaluation of texture, color, flavor, and general acceptability scores of selected samples ranked blend 3 > blend 2 > blend 1. The in vitro protein digestibility values ranked blend 1 > blend 2 > blend 3. An increase of up to 9.5% units in the protein digestibility values was observed when compared to the nonextruded raw blends.
Macromolecular Features of Amaranth Starch
Authors: Bello‐Pérez Luis Arturo , Colonna Paul , Roger Philippe , Paredes‐López Octavio 
Published: June 2007

ABSTRACTHigh‐performance size‐exclusion chromatography (HPSEC), static light scattering (SLS) and dynamic light scattering (DLS) techniques were used for the structural characterization of amaranth starch, solubilized in water by microwave heating in a high‐pressure vessel. Apparent average molar mass (M
w) gyration radius (R
G), and hydrodynamic radius (R
H) values were obtained from Berry and Zimm treatment of light‐scattering data. When heating time increased from 35 to 90 sec, the M
w, R
G, and R
H decreased, demonstrating a possible polymer degradation due to temperature. Apparent M
r values from HPSEC at 35 sec (27 ± 2 × 107 g/mol) and 50 sec (20 ± 2 × 107 g/mol) were lower than those determined by SLS (35 sec = 69 × 107 g/mol, 50 sec = 56 × 107 g/mol). However, at 70 and 90 sec, the inverse pattern was obtained. The fractal dimensions (d′f) from HPSEC study for samples dissolved for 35 (3.26), 50 (3.24), and 70 sec (3.14) are characteristic of a particle that has the internal structure of hard sphere, and for samples dissolved for 90 sec (2.19), are characteristic of a fully swollen, randomly branched macromolecule. From SLS, d′f decreased with increasing treatment time (d′f = 2.44, 2.18, 1.50, and 1.03 for 35, 50, 70, and 90 sec, respectively). The particle‐scattering factors and Kratky plots, well‐suited for studying the internal structure of a macromolecule, showed a sample degradation when treatment time increased. Results from DLS showed bimodal distributions with differences in the peak locations when treatment time increased. The ratio of R
G to R
H (ρ) for samples analyzed were between 0.88 and 1.3; these values are characteristic of a sphere or globular structure.
Methods to Evaluate Hydration and Mixing Properties of Nixtamalized Corn Flours
Authors: Lobeira R. , Almeida‐Dominguez H. D. , Rooney L. W. 
Published: June 2007

ABSTRACTRapid ViscoAnalyser (RVA), consistometer, and mixograph methods were developed to evaluate the pasting, hydration, and mixing characteristics of commercial nixtamalized corn flours (NCF) used for masa production. The effect of moisture level (51–58%) on the mixing characteristics of NCF was evaluated with the mixograph. Masas were subjectively evaluated for machinability properties. Masa with a low moisture level (51%) had reduced mobility and firmer texture, resulting in higher and wider mixograms. The mixograph was able to differentiate between the various stages of masa preparation. The first stage involves hydration of NCF particles, which causes the force to increase. Then masa develops cohesiveness and reaches maximum consistency. Finally, masa develops stickiness due to overmixing, which makes the curve narrower and lower. At a high moisture level (58%), masa is lubricated and plasticized and yields a softer texture with reduced mixing consistency, evident on the mixograph and in lower subjective hardness readings. Flours with higher water absorption capacities produced thick slurries with increased RVA viscosities and shorter consistometer travel distances. Short consistometer travel distances were significantly correlated to increased initial and maximum viscosities in the RVA. The mixograph, RVA, and consistometer methods can be used in NCF quality control programs.
Rheological Properties of (1→3),(1→4)‐β‐d‐Glucans from Raw, Roasted, and Steamed Oat Groats
Authors: Zhang D. , Doehlert D. C. , Moore W. R. 
Published: June 2007

ABSTRACTEffects of hydrothermal treatments (steaming, roasting) of oat grain on β‐glucan extractability and rheological properties were tested on oat cultivars with low (Robert) and high (Marion) β‐glucan content. Steaming of grain reduced the amount of β‐glucan that could be extracted, compared with raw or roasted grain, but the extracts from steamed grain had much greater viscosity. Increased extraction temperatures increased the amount and the average relative molecular mass (M
r) value of β‐glucan extracted. In boiling water extractions, the average M
r values among raw, roasted and steamed oat samples were equivalent, but extracts from steamed oat grain had significantly higher intrinsic viscosity than the extracts from roasted or raw oat grains. β‐glucan solutions purified from steamed grain extracts were very viscous and highly pseudoplastic, as described by the power law equation. Oat β‐glucan from steamed samples were more viscoelastic than β‐glucan from roasted or raw oat samples. Because viscous properties of β‐glucan from boiling water extracts are influencedhydrothermal treatments without affecting polymer molecular weight, polymer interaction with the solvent must be affected. Steaming may disrupt intramolecular cross‐linkings in native β‐glucan, allowing a linear chain configuration to generate greater viscosity.
Effects of Cultivar and Temperature During Grain Filling on Wheat Protein Content, Composition, and Dough Mixing Properties
Authors: Uhlen A. K. , Hafskjold R. , Kalhovd A.‐H. , Sahlström S. , Longva Å. , Magnus E. M. 
Published: June 2007

ABSTRACTThree wheat cultivars, Bastian, Polkka, and Tjalve, were grown in growth chambers at 9, 12, 15, 18, and 21°C during grain filling in 1994, 1995, and 1996. The wheat samples were analyzed for protein content and sodium dodecyl sulfate (SDS) sedimentation volume. The mixing properties of sifted flours were determined by mixograph, and the flour protein composition was determined by size‐exclusion fast protein liquid chromatography (SE‐FPLC). The protein content, sedimentation volume, and mixogram parameters were affected by the temperature during grain filling. The protein content increased as the temperature increased. The sedimentation volumes and the mixograph data showed temperature effects that could not be explained by variation in protein content. The proportion of the polymeric flour proteins increased with increasing temperature. Positive correlations were found between the proportion of polymeric proteins and SDS sedimentation volume and, within each year, between the proportion of polymeric proteins and mixograph peak time. Negative correlations were found between the proportion of low molecular weight flour proteins (proportion of fraction IV) and sedimentation volume. The differences in these quality parameters among cultivars exceeded the effect of temperature during grain filling.