bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rheological and Thermal Properties of Aged Starch Pastes from Three Waxy Maize Genotypes
Authors: Yuan R. C. , Thompson D. B. 
Published: June 2007

ABSTRACTThe rheological and thermal properties of aged starch gels (15:85 starch‐water) from three waxy maize genotypes (wx, wx sh1, and du wx) during storage (4°C for up to 25 days) were studied. After storage, changes of storage modulus (G′) and phase angle (δ) of the gels as a function of temperature were measured using oscillatory rheometry. For the du wx samples, G′ at 25°C increased rapidly during the first four days of storage at 4°C, compared to the gradual increases over the 25‐day storage period for the wx and wx sh1 samples. A peak in G′ at 45°C was observed during heating for the du wx samples after 10 days of storage and for the wx sample stored for 25 days. The G′ peak may have been due to syneresis in the gels. Retrogradation of amylopectin of the aged starch samples was examined using differential scanning calorimetry. The du wx starch had greater retrogradation enthalpies than the other two samples (which showed similar retrogradation behavior) throughout the storage. The retrogradation enthalpy of the du wx samples increased rapidly during the first seven days, followed by a slower increase through the rest of storage. For the wx and wx sh1 samples, no endotherm was observed during the first four days of storage, after which the enthalpy increased steadily as a function of storage time. Addition of sucrose delayed the formation of gel networks for all three starches. The greater tendency for gelling and retrogradation of the du wx starch might be attributed to the greater proportion of DP20–30 chains of the amylopectin.
Fusarium Species and 8‐Keto‐Trichothecene Mycotoxins in Manitoba Barley
Authors: Abramson D. , Clear R. M. , Usleber E. , Gessler R. , Nowicki T. W. , Märtlbauer E. 
Published: June 2007

ABSTRACTFusarium head blight, induced primarily by Fusarium graminearum, resulted in widespread damage to the Manitoba barley crops of 1993 and 1994, with contamination by deoxynivalenol (DON) and other 8‐keto‐trichothecenes. Visible Fusarium mold in samples of 1994 barley had little relationship to DON levels in the kernel as determined by gas chromatography‐mass spectrometry (GC‐MS). While samples of 1993 and 1994 barley showed a weak correlation between the logarithm of DON level and percentage of kernels infected by Fusarium graminearum (r = 0.79 and 0.71, respectively), the latter method is too lengthy and requires too much training for commercial application. A commercial enzyme immunoassay for DON gave results that correlated well with GC‐MS methods (r = 0.95 and 0.89, respectively) in samples of 1993 and 1994 barley and afforded a rapid and convenient method for screening. In barley samples from 1994, DON, 15‐acetylDON, 3‐acetylDON and 3,15‐diacetylDON were detected in the approximate ratio of 47:4:1:1. In view of the higher oral toxicities of 15‐acetylDON and 3‐acetylDON relative to DON, and the unknown oral toxicity of 3,15‐diacetylDON, GC‐MS assays might be advisable in samples positive for DON from enzyme immunoassay screening.
Differential Scanning Calorimetry Glass Transition Temperatures of White Bread and Mold Growth in the Putative Glassy State
Authors: Buera M. P. , Jouppila K. , Roos Y. H. , Chirife J. 
Published: June 2007

ABSTRACTDifferential scanning calorimetry (DSC) was used to determine the onset and end temperatures of the glass transition (Tg) for white bread equilibrated between 53 and 84% rh. Calorimetric Tg end values were ≈20°C higher than onset values, indicating that it is probably more correct to refer to a “glass transition range” rather than a glass transition temperature. Slices of white bread inoculated with a mixture of xerophilic molds were equilibrated to 75% rh (equilibrium moisture content of 14.5 g of water/100 g of dry material) and stored at 26°C. In a parallel experiment, some of the equilibrated bread samples were stored without mold inoculation and subjected to spontaneous contamination from the immediate surroundings. As suggested by measured Tg, bread stored at 75% rh and 26°C appeared to be glassy. After storage, samples of bread (inoculated or not) were spoiled by xerophilic molds, suggesting that Tg, as measured by DSC, cannot be considered as an absolute threshold for mold growth inhibition.
Influence of Salts and Aggregation of Gluten Proteins on Reduction and Extraction of High Molecular Weight Glutenin Subunits of Wheat
Authors: Bean S. R. , Lookhart G. L. 
Published: June 2007

ABSTRACTHigh‐molecular weight glutenin subunits (HMW‐GS) of wheat were extracted by various combinations of reducing agents, salt solutions, and solvents. Preferential extraction of 1D‐encoded HMW‐GS occurred when flours were extracted with Tris‐HCl SDS buffer at pH 6.8 containing 6% mercaptoethanesulfonic acid sodium salt (MESNA) and analyzed by SDS‐PAGE. Similar effects were also found when dithiothreitol or β‐mercaptoethanol were used in conjunction with nonchaotropic salts. If flours were first extracted with 50% 1‐propanol, the extraction procedure yielded all HMW‐GS, even in the presence of MESNA or high levels of salts. Addition of alcohols or chaotropes to the Tris buffer solutions containing MESNA or of solutions containing salt also extracted all HMW‐GS. The HMW‐GS reported most important in baking quality were found preferentially extracted by nonchaotropic salts and reducing agents. This is related to gluten aggregation and the gliadin‐glutenin interaction and structure.
Effects of Postharvest Processing on Texture Profile Analysis of Cooked Rice
Authors: Champagne Elaine T. , Lyon Brenda G. , Min Bong Kee , Vinyard Bryan T. , Bett Karen L. , Barton Franklin E. , Webb Bill D. , McClung Anna M. , Moldenhauer Karen A. , Linscombe Steve , McKenzie Kent S. , Kohlwey David E. 
Published: June 2007

ABSTRACTThe effects of drying conditions, final moisture content, and degree of milling on the texture of cooked rice varieties, as measured by texture profile analysis, were investigated. Instrumentally measured textural properties were not significantly (α = 0.05) affected by drying conditions, with the exception of cohesiveness. Cohesiveness was lower in rice dried at lower temperatures (18°C or ambient) than in that dried at the higher commercial temperatures. Final moisture content and degree of milling significantly (α = 0.05) affected textural property values for adhesiveness, cohesiveness, hardness, and springiness; their effects were interdependent. The effects of deep milling were more pronounced in the rice dried to 15% moisture than that dried to 12%. In general, textural property values for hardness were higher and those for cohesiveness, adhesiveness, and springiness were lower in regular‐milled rice dried to 15% moisture than in that dried to 12%. In contrast, hardness values were lower and cohesiveness, adhesiveness, and springiness values were higher in deep‐milled rice dried to 15% moisture than in that dried to 12% moisture. Deep milling resulted in rice with lower hardness values and higher cohesiveness, adhesiveness, and springiness values.
Near‐Infrared Reflectance Correlated to 100‐g Wet‐Milling Analysis in Maize
Authors: Dijkhuizen A. , Dudley J. W. , Rocheford T. R. , Haken A. E. , Eckhoff S. R. 
Published: June 2007

ABSTRACTAn understanding of the genetic control of starch, protein, and oil concentrations in the corn (Zea mays L.) kernel is essential for improvement of grain quality. Because large numbers of progenies are needed for genetic studies, a rapid, accurate, analytical procedure is necessary. As part of a study to identify chromosomal regions associated with starch and protein, a rapid near‐infrared reflectance (NIR) method and a more labor‐intensive 100‐g wet‐milling procedure were compared for consistency in ranking families and identifying quantitative trait loci (QTL) using a set of 200 F2S1 families from the cross of the 70th generations of the Illinois High Protein (IHP) × Illinois Low Protein (ILP) corn strains. NIR starch and wet‐milling starch values were highly correlated (r = 0.80), as were NIR protein and gluten measured by wet‐milling (r = 0.72). Chromosomal regions associated with NIR starch and wet‐milling starch were generally the same. Fiber concentration was significantly negatively correlated with starch and positively correlated with protein. Chromosome regions with significant associations with starch also had significant associations with fiber. The NIR method is satisfactory for measuring starch and protein in material with a wide range of variability in the early stages of a corn‐breeding program.
Objective Rollability Method for Corn Tortilla Texture Measurement
Authors: Suhendro E. L. , Almeida‐Dominguez H. D. , Rooney L. W. , Waniska R. D. 
Published: June 2007

ABSTRACTAn objective rollability method that imitates subjective rollability scores of corn tortilla texture was developed. Force and work required to pull an axle that caused a tortilla to roll around a dowel were measured. The sensitivity of the technique to detect changes in corn tortilla texture during storage was evaluated, and other factors affecting objective rollability and tortilla texture were studied. The objective rollability technique was fast, simple, and sensitive to changes in the tortillas, and worked effectively on commercial samples. Data was significantly correlated to subjective rollability and flexibility scores. Textural differences among fresh tortillas during the first 24 hr of storage, and among tortillas with different thicknesses and additives, were detected by the objective rollability method. Thicker tortillas required more force and work to roll than thin tortillas. The objective technique is more sensitive to changes in texture than subjective evaluations, which do not detect differences in tortilla variability during the first 24 hr after baking, and it can be used to evaluate the effect of formulation and processing changes on fresh and stored tortillas.
Effects of Enzymes and Oxidizing Agents on Shear Stress Relaxation of Wheat Flour Dough: Additions of Protease, Glucose Oxidase, Ascorbic Acid, and Potassium Bromate
Authors: Wikström Katarina , Eliasson Ann‐Charlotte 
Published: June 2007

ABSTRACTMeasuring shear stress relaxation with an established research rheometer after slowly applying large strain proved useful for characterizing the effects of different chemical and enzymatic additives. Baking tests done with and without added ascorbic acid indicated that the method can be used for predicting effects of such additives on breadbaking quality. The relaxation process for dough is discussed in terms of two flow processes, one occurring at short time periods and the other at longer time periods. The slowly applied large strain shear stress relaxation method provides information about stress relaxation behavior during the second flow process. The effects of two enzymes (protease and glucose oxidase) and two chemical additives (ascorbic acid and potassium bromate) were studied. The results are presented as the stress relaxation curve with the corresponding rate plot and the initial value of the stress. Addition of the oxidizing agents increased the second flow process times and decreased the relaxation rate during the second process. Protease shortened the second flow process times and increased the relaxation rate during the second process. Glucose oxidase separated the two flow processes by increasing the relaxation time of the second process and decreasing the relaxation time of the first process.
An Improved Process for Isolation of Corn Fiber Gum
Authors: Doner Landis W. , Chau Hoa K. , Fishman Marshall L. , Hicks Kevin B. 
Published: June 2007

ABSTRACTSequential alkaline extraction and alkaline hydrogen peroxide (AHP) bleaching have been used to prepare corn fiber gum in yields ranging from 21 to 40%, depending on the pH of the extraction medium. The pH was adjusted by using different ratios of NaOH and Ca(OH)2 The whitest product was obtained after AHP bleaching of the extract obtained using the lowest pH value. In order for the product gum to give its characteristic clear and low viscosity solutions, it was necessary to remove starch from the corn fiber substrate using α‐amylase. The water‐insoluble hemicellulose A fraction, a minor component, was removed by neutralizing AHP‐treated extracts before ethanol precipitation of the useful hemicellulose B (corn fiber gum) fraction. At ambient temperature, AHP bleaching was near optimal after ≈2 hr under the processing conditions used. High ratios of arabinose (39%) to xylose (50%) were present in the corn fiber gum extracted under various alkaline conditions, and the H2O2 processing step did not significantly alter these ratios. The same low levels of galactose (7%) and glucuronic acid (4%) were present regardless of the extraction conditions. Molecular mass of the corn fiber gum preparations ranged from 2.78 × 105 for the material extracted with Ca(OH)2 to 3.94 × 105 for the material extracted with NaOH. Molecular mass was unaffected by the H2O2 present in the second processing step. As expected for a carbohydrate polymer with a rather low uronic acid content, solution viscosities were unaffected by the presence of salt.
Characterization of Dynamic Viscoelastic Behavior of Wheat Flour Doughs at Different Moisture Contents
Authors: Masi P. , Cavella S. , Sepe M. 
Published: June 2007

ABSTRACTThree different flours were examined to study the influence of moisture content on the dynamic viscoelastic behavior of wheat flour dough. Doughs with moisture contents varying from 43 to 58% were submitted to dynamic testing using a mechanical spectrometer operating in frequency sweep mode, obtaining information about rheological response in the linear viscoelastic range. To characterize the influence of moisture content on the dynamic viscoelastic behavior of wheat flour dough, some hypotheses regarding the functional role of the water molecules were verified by applying reduction procedures of the rheological curves. By shifting the rheological curves along the vertical axis, it was possible to verify that varying the moisture content of the doughs not only changed dynamic properties but also modified viscoelastic response. By applying a reduction procedure similar to that used to estimate the constants of the Williams, Landel, and Ferry equation, we demonstrated that not only did the viscoelastic response of doughs vary, but that water molecules interfere with the dynamic by which relaxation phenomena take place. Finally, we proved that the rheological behavior of flour dough is similar to that of concentrated polymer solutions, and that it can be characterized by using a double reduction procedure, shifting the rheological curves along the vertical and horizontal axes, and obtaining a master curve that can be considered inherently characteristic of viscoelastic behavior.
Composition, Thermal Behavior, and Gel Texture of Prime and Tailings Starches from Garbanzo Beans and Peas
Authors: Czuchajowska Zuzanna , Otto Terri , Paszczynska Bozena , Baik Byung‐Kee 
Published: June 2007

ABSTRACTPrime and tailings starches of garbanzo beans and peas were separated and the chemical composition, physical properties, thermal behavior, and gel properties were determined. Starch granules <35 μm were 85% in garbanzo beans, 66.8% in a smooth pea cv. Latah, and only 18.4% in a smooth pea cv. SS Alaska. Amylose content of prime starch was 35.9% in garbanzo beans, 44.5–48.8% in smooth peas, and 86.0% in wrinkled pea cv. Scout. Tailings starch amylose content was at least 8% higher than the corresponding prime starch. The endothermic enthalpy value of garbanzo bean and two smooth pea prime starches ranged from 12.1 to 14.2 J/g, while prime starch from wrinkled peas gave a distinctly lower enthalpy value of 1.1 J/g. Differential scanning calorimetry endothermic enthalpy and amylograph pasting properties of prime starch were significantly related to its amylose content (P < 0.05). Prime starches of garbanzo beans and smooth peas produced highly cohesive elastic gels. Wrinkled pea prime starch formed the strongest (though brittle) gel, as indicated by high hardness (21.8 N), low cohesiveness (0.29), and low springiness (0.82). Hardness of gel stored at 22°C and at 4°C was positively correlated with amylose content of starch.
Intercultivar Variation in the Quantity of Monomeric Proteins, Soluble and Insoluble Glutenin, and Residue Protein in Wheat Flour and Relationships to Breadmaking Quality
Authors: Sapirstein H. D. , Fu B. X. 
Published: June 2007

ABSTRACTA new fractionation procedure based on differential solubility was applied to wheat flour proteins to evaluate the relationship between protein fractions and functionality for breadmaking. Flour was initially extracted with 50% 1‐propanol. Monomeric proteins (mainly gliadins) and soluble glutenin contained in the 50% propanol soluble extract were fractionated by selective precipitation of the glutenin by increasing the concentration of 1‐propanol to 70%; monomeric proteins remain in the supernatant. Insoluble glutenin in the 50% propanol insoluble residue was extracted using 50% 1‐propanol containing 1% dithiothreitol (DTT) at 60°C. Protein in the final residue was extracted using SDS with or without DTT. It comprised mainly Glu‐1D high molecular weight glutenin subunits and nongluten polypeptides. For seven Canadian cultivars of diverse breadmaking quality, there was relatively little variation in the percentage of flour protein corresponding to monomeric proteins (48–52%) and residue protein (14–18%). In contrast, intercultivar variation in soluble and insoluble glutenin was substantial, with contents of 10–20% and 12–28% of flour protein, respectively. Soluble and insoluble glutenin were also highly correlated with physical dough properties, accounting for 83–95% of the variation of individual dough rheological parameters (except dough extensibility), and ≈ 74% of the variation in loaf volume. In contrast, monomeric and residue protein fractions were poorly associated with breadmaking quality. However, among the four protein fractions, only residue protein was significantly correlated (r = ‐0.79) with dough extensibility. The flour sample with the highest and lowest concentrations of insoluble and soluble glutenin, respectively, as well as marginally the lowest concentrations of monomeric and residue proteins was Glenlea, a cultivar of the Canada Western Extra Strong Red Spring wheat class which characteristically possesses distinctly strong dough mixing properties.
Solubilization of Arabinoxylans from Isolated Water‐Unextractable Pentosans and Wheat Flour Doughs by Cell‐Wall‐Degrading Enzymes
Authors: Petit‐Benvegnen M.‐D. , Saulnier L. , Rouau X. 
Published: June 2007

ABSTRACTWater‐unextractable pentosans (WUP) isolated from the flours of three wheat cultivars (Apollo, Soissons, Thésée) were treated with enzymes to solubilize the arabinoxylans. The water‐unextractable arabinoxylans from the three cultivars had similar susceptibility to solubilization by enzymes: Grindamyl S 100 (GS100), a commercial preparation for baking, rich in pentosanase activities that originated from an Aspergillus niger culture; and three endoxylanases (E1, E2, E3), an arabinofuranosidase (Af), a β‐ glucanase (βG), and a ferulate esterase (FAE) purified from GS100. A cellulase (C) and a pure endoglucanase (eG) from Trichoderma reesei were also used. GS100 was able to solubilize high molecular weight arabinoxylans (HMWAX) from WUP that markedly enhance the viscosity of the reaction mixture supernatants. The endoxylanase E1 was responsible for this solubilizing activity of GS100, whereas E2 and E3 made only a very low contribution. Combining E1 with FAE led to a limited increase in the arabinoxylan‐solubilizing effect. Also, enzymes hydrolyzing cellulose and β‐glucans slightly improved the arabinoxylan solubilization from WUP when combined with GS100 or E1, but produced arabinoxylans of lower intrinsic viscosity. Similar effects of the enzymes were observed on arabinoxylan solubilization when applied to dough instead of isolated WUP.
A Simple Wheat Flour Swelling Test
Authors: Fu B. X. , Kovacs M. I. P. , Wang C. 
Published: June 2007

ABSTRACTFlour swelling tests have been widely used to assess the intercultivar differences in starch properties. This note describes a modified flour swelling test which uses ≈30 mg of flour. It avoids the use of a high‐temperature water bath, and does not require a set of uniform and leak‐proof tubes. The modified procedure offers a simpler and more rapid alternative to those previously reported, and provides a similar level of discrimination and precision. It is particularly suitable as a micro‐scale early generation test for wheat flour swelling properties.
Textural Images Analysis of Pasta Protein Networks to Determine Influence of Technological Processes
Authors: Fardet A. , Baldwin P. M. , Bertrand D. , Bouchet B. , Gallant D. J. , Barry J.‐L. 
Published: June 2007

ABSTRACTThe structure of pasta is largely governed by the presence of a structured protein network. This work analyzed the protein network textures of various cooked pasta products through textural image analysis. Six different pasta types were investigated: reference pasta made from durum semolina; pasta enriched with gluten proteins from soft wheat flour at 10 and 20%; autoclaved pasta; soft wheat flour pasta; and pasta made from reconstituted flour fractions. Pasta samples were sectioned, and each crosssection consisted of three distinct zones (central, intermediate, and external) based on the state of swelling of starch granules for each pasta product. Digital images of the protein network in each zone were acquired using confocal laser scanning microscopy. Textural image analysis was then performed. Similarities and differences in protein network texture were assessed by principal component, stepwise discriminant, and variance analyses. With the exception of autoclaved pasta, protein network structure differed greatly with the position in the pasta. Furthermore the effect of technological treatments was greatly influenced by the position in pasta. The most significant differences in protein network structure were obtained with the autoclaved and 20% protein‐enriched samples.
Low α‐Amylase Starch Digestibility of Cooked Sorghum Flours and the Effect of Protein
Authors: Zhang Genyi , Hamaker Bruce R. 
Published: June 2007

ABSTRACTThe comparably low starch digestibility of cooked sorghum flours was studied with reference to normal maize. Four sorghum cultivars that represent different types of endosperm were used. Starch digestibilities of 4% cooked sorghum flour suspensions, measured as reducing sugars liberated following α‐amylase digestion, were 15–25% lower than for cooked maize flour, but there were no differences among the cooked pure starches. After the flours were predigested with pepsin to remove some proteins, the starch digestibility of cooked sorghum flours increased 7–14%, while there was only 2% increase in normal maize; however, there was no effect of pepsin treatment on starch digestibility if the flours were first cooked and then digested. After cooking with reducing agent, 100 mM sodium metabisulfite, starch digestibility of sorghum flours increased significantly while no significant effect was observed for maize. Also, starch solubility of sorghum flours at 85 and 100°C was lower than in maize, and sodium metabisulfite increased solubility much more in sorghum than in maize. Differential scanning calorimetry results of the flour residue after α‐amylase digestion did not show any peaks over a temperature range of 20–120°C, indicating that sorghum starches had all undergone gelatinization. These findings indicate that the protein in cooked sorghum flour pastes plays an important role in making a slowly digesting starch.