bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Weight Distribution of Wheat Proteins
Authors: Southan M. , MacRitchie F. 
Published: June 2007

ABSTRACTThe molecular weight distribution (MWD) of wheat proteins is becoming recognized as the main determinant of physical dough properties. Studies of high polymers have shown that properties such as tensile strength are related to a fraction of polymer with molecular weight above a critical value and the MWD of this fraction. Elongation to break is treated as a kinetic process with energies of activation for breaking noncovalent bonds and for chain slippage through entanglements. These considerations are related to tensile properties of wheat flour doughs such as those measured by the extensigraph. The MWD of wheat proteins is determined by the relative amounts of monomeric and polymeric proteins and the MWD of the polymeric proteins. The latter, in turn, depends on the ratio of high molecular weight glutenin subunits (HMW‐GS) to low molecular weight glutenin subunits (LMW‐GS), the specific HMW‐GS that result from allelic variation, and the presence of modified gliadins that act as chain terminators. The role of these compositional variables in determining dough extensional properties is discussed in terms of present knowledge. Determination of MWD of wheat proteins is hindered by the difficulty of their solubilization and the lack of methods for reliably measuring very high molecular weights. Among the promising techniques for achieving these measurements are multiangle laser light scattering (MALLS) and field flow fractionation (FFF).
Wheat Gluten Swelling and Partial Solubility with Potential Impact on Starch‐from‐Gluten Separation by Ethanol Washing
Authors: Robertson G. H. , Cao T. K. , Ong I. 
Published: June 2007

ABSTRACTSwelling of wheat gluten may be a contributing factor in washing or displacement separation of gluten and starch using cold ethanol. To test this hypothesis, dissolution and swelling (settled volume or mass absorption) of a commercial gluten are reported here for the first time as a function of both temperature and ethanol solution concentration. In this test system, instant and substantial volumetric swelling was observed over most of the range of ethanol concentrations but not at 100%, v/v, ethanol. Settled volume reached a maximum of 50–70%, v/v, ethanol, and this was up to 3.5× the volume in absolute ethanol at 22°C and 2× the volume at −15°C. This maximum closely corresponds to the maximum dissolution of whole gluten and prior literature reports of full dissolution of gliadin. The reduction of settled volume at low temperature reflects the possible role of undissolved, gliadin‐class proteins in reinforcing the gluten structure and limiting the ultimate swelling. The data suggest gluten‐swelling properties as a contributing factor to the success of the cold ethanol, glutenfrom‐starch separation process.
Assessing Degree of Cook During Corn Nixtamalization: Impact of Processing Variables
Authors: Sahai D. , Mua J. P. , Surjewan I. , Buendia M. O. , Rowe M. , Jackson D. S. 
Published: June 2007

ABSTRACTNixtamalization involves cooking and steeping corn in a lime solution, washing the corn (nixtamal), and stone grinding nixtamal to form a corn dough or masa. Masa is used to produce nixtamalized products (corn tortillas, tortilla chips, corn chips, taco shells, etc.) by forming and baking or deepfat frying. The degree of corn kernel cook determines the quality and texture of masa. Response surface methodology (RSM) was used as an experimental design to study the impact of process variables (cook temperature, cook time, initial steep temperature, and steep time) on the degree of cook measured using a Rapid Visco Analyser (RVA) and differential scanning calorimetry (DSC). RSM data exhibited significant (P < 0.005), although not predictive, linear models for RVA peak viscosity (r2 = 0.63), setback (r2 = 0.61), final viscosity (r2 = 0.61), and peak time (r2 = 0.57), indicating a dependence of these parameters on nixtamalization conditions. Peak viscosity, setback, and final viscosity increased linearly with steep time. DSC enthalpy (r2 = 0.83) and peak temperature (r2 = 0.89) of freezedried masa also exhibited significant (P < 0.0001) linear regression models with processing variables. DSC enthalpy increased with an increase in steep time, suggesting that starch is annealed during steeping. This study demonstrated that fundamental starch properties were altered on extended steeping during nixtamalization.
Recovery of Fiber in the Corn Dry‐Grind Ethanol Process: A Feedstock for Valuable Coproducts
Authors: Singh Vijay , Moreau Robert A. , Doner Landis W. , Eckhoff Steven R. , Hicks Kevin B. 
Published: June 2007

ABSTRACTA new process was developed to recover corn fiber from the mash before fermentation in dry‐grind ethanol production. In this process, corn is soaked in water (no chemicals) for a short period of time and then degermed using conventional degermination mills. In the remaining slurry, corn coarse fiber is floated by increasing the density of the slurry and then separated using density differences. The fiber recovered is called quick fiber to distinguish it from the conventional wet‐milled fiber. This study evaluated the percent of quick fiber recovery for a normal yellow dent and high oil corn hybrid. The quick fiber was analyzed for levels of corn fiber oil, levels of ferulate phytosterol esters (FPE) and other valuable phytosterol components in the oil and compared with conventional wet‐milled corn coarse and fine fiber samples. Fiber samples were also analyzed and compared for yields of potentially valuable corn fiber gum (CFG, hemicellulose B). Comparisons were made between the quick fiber samples obtained with and without chemicals in the soakwater. An average quick fiber yield of 6–7% was recovered from the two hybrids and represented 46–60% of the total fiber (fine and coarse) that could be recovered by wet‐milling these hybrids. Adding steep chemicals (SO2 and lactic acid) to the soakwater increased the quick fiber yields, percent of FPE recoveries, and total percent of phytosterol components to levels either comparable to (for the dent corn hybrid) or higher than (for the high oil corn hybrid) those recovered from the total conventional wet‐milled fiber samples. CFG yields in the quick fiber samples were comparable to those from the wet‐milled fiber samples. CFG yields in the quick fiber samples were not significantly affected by the addition of chemicals (SO2 and lactic acid) to the soakwater.
Use of Regression and Discriminant Analyses to Develop a Quality Classification System for Hard Red Winter Wheat
Authors: Baker Scott , Herrman Timothy J. , Loughin Thomas 
Published: June 2007

ABSTRACTAn attempt to create a segregation system that uses rapid quality detection instrumentation and represents value to millers and bakers led to the development of a single value called “dough factor.” The dough factor value represents the amount of flour‐water dough that can be produced by a given unit of wheat. Samples of hard red winter wheat (≈100/location) collected from five Kansas country elevators during the 1995 and 1996 harvests were evaluated for dough factor. Single kernel properties, sample protein content, and test weight measurements were subjected to regression and discriminant analyses for the purpose of developing a dough factor classification system. Regression analysis identified kernel weight, kernel weight standard deviation, and protein as important characteristics for predicting dough factor, however, the resulting model possessed poor predictive ability (adjusted R2 = 0.39). Classifying wheat into dough factor groups of <107, 107–112.9, and ≥113 using discriminant analysis resulted in an accuracy of 56%, while discriminant analysis correctly placed wheat into two dough factor groups (<113 and ≥113) with an 80% accuracy. Creation of a dough factor classification system using single kernel measures, kernel protein, and wheat cultivar correctly classified 86.3 and 68.8% of the wheat samples into dough factor groups <113 and ≥113, respectively. In the dough factor group ≥113, cost savings associated with higher flour yields and water absorption were $0.15/cwt of flour and $0.65/1,000 lb of dough, respectively. Increases in processing efficiency for both the miller and the baker would be expected to further differentiate the value between the two dough factor groups.
Antioxidant Activity and Phenolic Contents of Oat Groats and Hulls
Authors: Emmons Cheryld L. , Peterson David M. 
Published: June 2007

ABSTRACTResearch was initiated to measure antioxidant activity of extracts from oat (Avena sativa L.) groats and hulls and the concentrations of phenolic substances that may contribute to antioxidant activity. Antioxidant activity of ethanolic extracts of four cultivars was evaluated by an in vitro assay that measures the inhibition of coupled autoxidation of linoleic acid and β‐carotene. Total phenolic content was determined using Folin and Ciocalteau's phenol reagent and was expressed as gallic acid equivalents. Phenolic compounds were separated by reversed‐phase HPLC and detected at 290 nm. Peaks were identified by comparing retention times and spectra with known standards and verified with internal standards. Groats had significantly higher antioxidant activity than hulls. For two cultivars, total phenolic content was similar in groats and hulls, whereas one cultivar had higher and another lower total phenolic content in groats than hulls. Ten phenolic compounds were separated and identified in extracts, and one flavan‐3‐ol and three avenanthramides were tentatively identified. The concentrations of many of these compounds differed among cultivars and between fractions. In general, caffeic acid and the avenanthramides were predominantly found in groats, whereas many of the other phenolics were present in greater concentrations in hulls.
Comparison of Small and Large Deformation Measurements of Whole Meal Rye Doughs
Authors: Autio K. , Flander L. , Heinonen R. , Kinnunen A. 
Published: June 2007

ABSTRACTThe rheological properties of rye flour‐water‐salt doughs prepared from different flour types (different falling number and coarseness) at different water levels were studied after mixing and after 90 min of incubation (30°C and 80% rh). Both the effect of water and the coarseness of the flour had significant effects on storage modulus (G′) measured by oscillatory test in the linear viscoelastic region and on compressional force measured at large deformation. The results of the two rheological methods correlated very well with each other (correlation coefficients varied in the different doughs at r = 0.975–0.999). Dough rheological measurements suggested that falling number did not have a statistically significant effect on dough rheology after mixing or incubation. Although the two rheological methods correlated well, the responses for incubation were different. In the small deformation method, the storage modulus of all doughs, independent of the falling number, decreased during incubation, whereas in the large deformation method, only the hardness of doughs made from flours with lower falling number decreased during incubation. The rheological measurements of doughs after mixing and the viscosity measurements of flourwater suspension at 30 and 40°C did not correlate with each other. Total pentosans have great effect on viscosity measurements of flour‐water suspensions, whereas flour particle size and soluble pentosans correlated more with rheological properties of doughs (r = 0.851 between G′ and soluble pentosans).
Allelic Variation at Glu‐D1 Locus for High Molecular Weight (HMW) Glutenin Subunits: Quantification by Multistacking SDS‐PAGE of Wheat Grown Under Nitrogen Fertilization
Authors: Zhu J. , Khan K. , Huang S. , O'Brien L. 
Published: June 2007

ABSTRACTTwo biotypes of an Australian wheat cultivar, Warigal, differing only in the Glu‐D1 high molecular weight (HMW) glutenin subunits 5+10 and 2+12 were used in this study. The objective was to examine the effects of nitrogen fertilization and allelic variation at the Glu‐D1 locus on the characteristics of glutenin polymers. Unreduced proteins containing the SDS‐soluble glutenins and the other protein classes were analyzed by multistacking SDS‐PAGE which separates the glutenin into six distinctly different‐sized aggregates. The results showed that nitrogen fertilization significantly increased protein quantity, ratio of polymers to monomeric proteins, and sizes of SDS‐soluble glutenins. Nitrogen fertilization affected the proportions of HMW subunits in both SDS‐soluble and SDS‐insoluble glutenin polymers and the ratio of x to y subunits in SDS‐insoluble glutenin polymers. Nitrogen fertilization, however, did not cause a significant change in ratio of SDS‐soluble to SDS‐insoluble glutenins. SDS‐insoluble glutenins had a greater ratio of HMW to LMW and x to y subunits, especially with a higher increase of 1Dx subunits, than SDS‐soluble glutenins. The HMW/LMW subunit ratio and the x/y subunit ratio may be used to predict sizes of glutenin polymers. The biotype with 5+10 subunits had a greater x/y subunit ratio in the SDS‐insoluble glutenins than the 2+12 type. A greater proportion of subunit 5 was formed than subunit 2 in the SDS‐insoluble glutenin polymers. Both nitrogen fertilization and allelic variation at Glu‐D1 loci could affect the characteristics of glutenin polymers.
Wheat Starch Effects on the Textural Characteristics of Puffed Brown Rice Cakes
Authors: Orts W. J. , Glenn G. M. , Nobes G. A. R. , Wood D. F. 
Published: June 2007

ABSTRACTA process was described for creating puffed wheat starch based or hybrid starch and rice snack foods processed in a rice cake puffing machine. Puffed cakes consisting of wheat starch and whole grain brown rice, created by mixing wheat starch beads with brown rice before processing and puffing for 10 sec (cooking time) at 210°C, exhibited greater flexibility and fracture strength than traditional rice cakes. The density of puffed wheat starch cakes decreased with increasing moisture content independent of particle size for particles 0.8–5 mm in diameter. The addition of sucrose and shortening promoted the formation of lower density puffed cakes at lower moistures, while salt had little effect.
Application of the Single‐Kernel Characterization System to Durum Wheat Testing and Quality Prediction
Authors: Sissons M. J. , Osborne B. G. , Hare R. A. , Sissons S. A. , Jackson R. 
Published: June 2007

ABSTRACTThe Single Kernel Characterization System (SKCS 4100) measures single kernel weight, width, moisture content, and hardness in wheat grain with greater speed than existing methods and can be calibrated to predict flour starch damage and milling yield. The SKCS 4100 is potentially useful for testing applications in a durum improvement program. The mean SKCS 4100 kernel weight and moisture values from the analysis of 300 individual kernels gave good correlations with 1,000 kernel weight (r2 = 0.956) and oven moisture (r2 = 0.987), respectively. Although significant correlations were obtained between semolina mill yield and SKCS 4100 weight, diameter, and peak force, they were all very low and would be of little use for prediction purposes. Similarly, although there were significant correlations between some SKCS 4100 parameters and test weight and farinograph parameters, they too were small. The SKCS 4100 has been calibrated using either the single kernel hardness index or crush force profile to objectively measure the percentage vitreous grains in a sample with reasonable accuracy, and it correlates well with visual determination. The speed and accuracy of the test would be of interest to grain traders. An imprecise but potentially useful calibration was obtained for the prediction of semolina mill yield using the SKCS 4100 measurements on durum wheat. The SKCS 4100 is useful for some traits such as hardness, grain size and moisture for early‐generation (F3) selection in a durum improvement program.
Yield, Protein Content, and Viscosity of Starch from Wet‐Milled Corn Hybrids as Influenced by Environmentally Induced Changes in Test Weight
Authors: Yang P. , Shunk R. J. , Haken A. E. , Niu Y. X. , Zou S. H. , Buriak P. , Eckhoff S. R. , Tumbleson M. E. 
Published: June 2007

ABSTRACTForty‐three yellow dent corn samples of five different hybrids varying in test weight and moisture content were obtained from 14 different locations in 1993. The locations for acquired samples were selected randomly to cover a wide range of test weights based on preliminary data from eight states of the corn belt where 94% of the U.S. corn crop was produced in 1993. Samples were wet‐milled using a 100‐g standard laboratory‐scale wet‐milling procedure. Protein content in starch and starch viscosity were determined. Starch yield, protein content in starch, and starch viscosity were not affected significantly by test weight.
Simple Determination of Gluten Protein Types in Wheat Flour by Turbidimetry
Authors: Wieser Herbert 
Published: June 2007

ABSTRACTA simple method based on turbidimetry has been developed for the quantitative determination of total gliadins, glutenin subunits, and high and low molecular weight (HMW and LMW) subunits of glutenin. The standard procedure includes the subsequent extraction of wheat flour (100 mg) with a salt solution, with 50% 2‐propanol (gliadins), and with 50% propanol under reducing conditions and increased temperature (glutenin subunits). Aliquots of the gliadin and the glutenin extracts are mixed with 2‐propanol to a final concentration of 83%, and the turbidity of the precipitates is measured photometrically at 450 nm and 20°C after 40 min. Another aliquot of the glutenin extract is mixed with acetone to a final concentration of 40% acetone, and precipitated HMW subunits are determined turbidimetrically after 30 min. The sample is then filtered, and an aliquot of the filtrate is mixed with 2‐propanol to a final concentration of 77% to determine the precipitated LMW subunits. Control analyses with reversed‐phase HPLC on C8 silica gel indicate that the precipitation of the different protein types is quantitative and specific, and studies of 16 different wheat flours demonstrate the strong correlation between quantification by HPLC and turbidimetry. The turbidimetric measurements are reproducible, linear over a wide absorbance range (0.2–1.7), and sufficiently sensitive to analyze 40 μg of protein or 20 mg of flour. The absolute amounts of protein types in flour can be determined by means of calibration curves with protein standards (gliadins, HMW, and LMW subunits). Altogether, the developed method is simple, accurate, sensitive, and specific for the different protein types. The total procedure takes ≈6 hr for the analysis of six flour samples in parallel or ≈4 hr for three samples in overlapping extraction steps. The chemicals used are inexpensive, scarcely toxic, and easy to dispose.
Sensory and Instrumental Relationships of Texture of Cooked Rice from Selected Cultivars and Postharvest Handling Practices
Authors: Lyon Brenda G. , Champagne Elaine T. , Vinyard Bryan T. , Windham William R. 
Published: June 2007

ABSTRACTMeasurement of cooked rice texture attributes by sensory and instrumental methods is important because of the increased popularity of rice and rice products by globally diverse cultures. Many factors influence cooked rice texture, including cultivar, physicochemical properties, postharvest handling practices (milling degree, drying conditions, and final moisture), and cooking method. Information on the relationships between sensory, physical, and chemical characteristics will lead to better methods to quickly evaluate and predict end‐use qualities, which will help to match rices with specific characteristics to populations that demand those attributes. This article reports the relationships between two modes of measuring texture attributes of rices: sensory and instrumental texture analyzers. Six medium‐ and short‐grain rice samples differing by cultivar or growing location were dried to achieve final moisture levels of 12 or 15% and then regular‐ or deep‐milled (n = 120). Correlations between individual sensory descriptive attributes and instrumental texture profile parameters were weak. Of only 12 significant correlations, the highest value was r = 0.624. Combined sensory and instrumental data were factor‐analyzed. This analysis revealed that sensory attributes still accounted for the most variation (35.32% out of 76.55%). Sensory descriptive analysis was more sensitive to subtle changes in initial texture perception including parameters relating to stickiness and adhesiveness. The two‐cycle compression test for texture profile parameters (i.e., hardness, cohesiveness, adhesiveness, gumminess, springiness, and chewiness) accounted for less variation in the data on texture differences.
Atomic Force Microscopy (AFM) Study of Interactions of HMW Subunits of Wheat Glutenin
Authors: Humphris Andrew D. L. , McMaster Terence J. , Miles Mervyn J. , Gilbert Simon M. , Shewry Peter R. , Tatham Arthur S. 
Published: June 2007

ABSTRACTAtomic force microscopy (AFM) has been used to study the noncovalent interactions of alkylated HMW subunit 1Dx5 and a M
r 58,000 peptide derived from the central repetitive domain. Both protein and peptide align side‐by‐side to form fibrils, the HMW subunit forming a branched network, and the peptide forming linear rods. The N‐ and C‐terminal domains of the subunit would, therefore, appear to contain regions that interact through noncovalent interactions in the absence of disulfide bond formation. These regions may be of importance in facilitating disulfide bond formation during protein body development.
Effects of Microencapsulated High‐Fat Powders on the Empirical and Fundamental Rheological Properties of Wheat Flour Doughs
Authors: O'Brien C. M. , Grau H. , Neville D. P. , Keogh M. K. , Reville W. J. , Arendt E. K. 
Published: June 2007

ABSTRACTMicroencapsulated high‐fat powders are a healthy and convenient alternative to fats normally used in cereal‐based products. In powder form they are easier to use than block fat. Microencapsulation involves dispersion of the fat using homogenization. The globules are then fixed by spray‐drying. Empirical and fundamental rheological tests were conducted on doughs containing commercial vegetable fat and four microencapsulated high‐fat powders. The doughs were compared with a standard dough containing no fat. The powders contained 70% vegetable fat or milk fat. The encapsulating agent used was either sodium caseinate or whey protein concentrate (5–10%). Sucrose or lactose were also present in the powders (20–25%). The powders were manufactured at low‐ or high‐pressure homogenization. Farinograph and extensigraph tests were performed on all doughs. Dynamic oscillation tests were conducted in the linear visco‐elastic region of the dough. Addition of fat and microencapsulated high‐fat powders produced using low‐pressure homogenization reduced the complex modulus of the doughs. The results showed an increase in phase angle with incorporation of commercial fat and the microencapsulated high‐fat powders. Scanning electron microscopy was conducted to examine the effects of the additives on dough structure. This study demonstrated that microencapsulated high‐fat powders, especially powders produced using low‐pressure homogenization, had some beneficial effects on dough rheology when compared with doughs produced with commercial fat.