bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxido‐Reductases and Lipases as Dough‐Bleaching Agents
Authors: Gélinas P. , Poitras E. , McKinnon C. M. , Morin A.
Published: June 2007

To replace benzoyl peroxide as a bread dough‐bleaching agent, pure and commercial oxido‐reductases (peroxidases, catalases, glucose oxidases, lipoxygenase, and laccase) were screened based on degradation of β‐carotene in a liquid system (5 μg of β‐carotene/mL of 0.1M citrate phosphate buffer at pH 5.5 or 6.5) or dough. Peroxidases had the best bleaching activity; some catalases also showed bleaching potential in a liquid system but not in bread dough, suggesting that screening enzymes in liquid media has limited application for dough. In 100 g of flour, combinations of peroxidase (3,000 U), lipase (815–1,630 U), and linoleic acid (0–300 mg) completely bleached bread dough.
Glucose Oxidase Effects on Gluten and Water Solubles
Authors: Vemulapalli V. , Hoseney R. C.
Published: June 2007

Hydrogen peroxide was responsible for the improving the effect of glucose oxidase in breadmaking. The mechanism by which H2O2 has its effect is not known. The objective of this study was to determine whether the H2O2 produced by glucose oxidase affected the gluten proteins or the water‐soluble fraction of flour. Glucose oxidase had no effect on gluten protein as measured by protein solubility or the relative viscosity of soluble protein (solubilized using 1.5% w/v SDS). However, glucose oxidase did affect the water‐soluble fraction. The sulfhydryl content of the water‐soluble fraction extracted from flour or dough decreased in the presence of glucose oxidase. Glucose oxidase also caused oxidative gelation of the water‐soluble fraction extracted from flour. However, the viscosity of the water‐soluble fraction extracted from fermented doughs containing glucose oxidase decreased when higher levels of glucose oxidase were used (≥5.0 units of glucose oxidase). Glucose oxidase appeared to have the same oxidizing action independent of whether the water‐soluble fraction was boiled or not.
Retrogradation of du wx and su2 wx Maize Starches After Different Gelatinization Heat Treatments
Authors: Liu Qiang , Thompson Donald B.
Published: June 2007

Retrogradation of du wx and su2 wx starches after different gelatinization heat treatments was studied by differential scanning calorimetry. Suspensions of 30% (w/w) starch were initially heated to final temperatures of 55–180°C. Gelatinized starch was cooled and stored at 4°C. Starch retrogradation in the storage period was influenced by initial heat treatments. Retrogradation of du wx starch was rapid: when initially heated to 80–105°C, retrogradation enthalpy was ≈10 J/g after one day at 4°C. The retrogradation enthalpy was ≈15 J/g after 22 days of storage, and reached a maximum of 16.2 J/g after 40 days of storage. For du wx starch, application of the Avrami equation to increases in retrogradation enthalpy suggests retrogradation kinetics vary with initial heating temperature. Furthermore, starch retrogradation may not fit simple Avrami theory for initial heating ≤140°C. Retrogradation of su2 wx starch was slow. After 30 days of storage at 4°C, the maximum retrogradation enthalpy for all initial heating temperatures tested was 7.0 J/g, for the initial heating to 80°C. This work indicates that gelatinization heat treatment in these starches is an important factor in amylopectin retrogradation, and that the effect of initial heat treatment varies according to the genotype.
Fractionation of High‐Amylose Maize Starches by Differential Alcohol Precipitation and Chromatography of the Fractions
Authors: Klucinec Jeffrey D. , Thompson Donald B.
Published: June 2007

Three high‐amylose maize starches (HAS) and a common corn starch (CCS) were subjected to differential alcohol precipitation using isoamyl alcohol and 1‐butanol to obtain fractions designated as amylose (AM), amylopectin (AP), and intermediate material (IM). For each starch, IM had a blue value and an iodine binding wavelength maximum (λmax) between the λmax of the respective AM and AP. Size‐exclusion chromatography (SEC) showed similarities in the AM from CCS and HAS. HAS AP had higher blue values and iodine binding λmax values than CCS AP. SEC of the intact HAS AP and IM both showed large proportions of material eluting after the void volume (45–85%) when compared to CCS AP and IM. Chain length (CL) distributions of debranched AP and IM indicated that these fractions from each starch were highly branched, and that AP had a shorter average chain length than IM. Consequently, the differential precipitation behavior of the HAS AP and IM appears dependent on general branching structure rather than size. We conclude that in both CCS and HAS, AP and IM are subsets of the branched molecules with AP as the predominant fraction. For HAS, AP and IM include molecules of a size typical for AM and contain a higher proportion of chains that are longer than those of CCS AP. Differential alcohol precipitation is a useful method of separating amylose, amylopectin, and intermediate material from HAS.
Nonstarch Polysaccharides from Preprocessed Wheat Bran: Carbohydrate Analysis and Novel Rheological Properties
Authors: Cui Wuwei , Wood Peter J. , Weisz John , Beer Michael U.
Published: June 2007

Wheat preprocessing technology produces a bran fraction rich in both soluble (8.5%) and insoluble (29.2%) fibers. The fraction, prepared by the Tkac and Timm commercial process, contained 9% alkaline extractable nonstarch polysaccharides (NSP). Conditions for extraction of NSP were chosen on the basis of both yield and molecular size of product. The extracted NSP was composed of an arabinoxylan and a mixed linkage(1→3)(1→4)‐β‐d‐glucan. The NSP differed from previously reported wheat pentosans by exhibiting shear‐thinning flow behavior at low concentration in water (0.5%, 25°C) and, more importantly, forming a thermally reversible gel upon cooling at 4°C. This unique gelling property is neither the commonly described irreversible gelation brought about by oxidation of wheat endosperm pentosans nor a characteristic property of cereal β‐glucan. The low degree of substitution of the xylan chain of the arabinoxylan (xylose‐to‐arabinose ratio = 3) in this NSP might be responsible for the rheo‐logical behavior.
Survey of Starch Particle‐Size Distribution in Wheat and Related Species
Authors: Stoddard F. L.
Published: June 2007

The existence of a population of small (B‐type) starch granules (<10 μm diameter) in addition to the major (A‐type) granules presents a problem for starch‐gluten manufacture and certain other wheat processes. A survey of starches in 761 accessions of cultivated wheats, ryes, and wild relatives was conducted. Starch was extracted from grains and analyzed for particle‐size distribution by laser diffraction. Australian hexaploid wheat cultivars showed 23–50% of starch in B granules. Landraces from Asia extended this range down to 17%. Tetraploid wheats (Triticum turgidum) showed a similar range of 17–47%, and einkorn wheat (T. monococcum) ranges were 23–62%. The range for B‐granule content in rye was only 20–40%, while that in triticale and T. tauschii went down to 15%. The results show that there are clear prospects for manipulating the starch particle‐size distribution of cultivated wheats.
Fusarium Head Blight: Effect of Fungal Proteases on Wheat Storage Proteins
Authors: Nightingale M. J. , Marchylo B. A. , Clear R. M. , Dexter J. E. , Preston K. R.
Published: June 2007

The effect of proteolytic enzymes, associated with Fusarium head blight, on wheat storage proteins and dough functionality was studied. Fusarium damaged kernels (FDK) and sound kernels were hand‐picked from F. graminearum Schwabe and F. avenaceum (Fr.) Sacc. infected samples of bread and durum wheat. Scanning electron microscopy revealed significant degradation of endosperm protein in FDK. Storage proteins from FDK and sound kernels were analyzed by SDS‐PAGE, RP‐HPLC, and SE‐HPLC. Total storage protein was lower in FDK but no significant qualitative differences in protein were detected by either RP‐HPLC or SDS‐PAGE. SE‐HPLC was used to follow the hydrolysis of wheat storage protein by proteolytic enzymes found in FDK and a pure culture of F. graminearum. Selective inhibition of proteolytic activity by p‐chloromercuribenzoate, and not soybean trypsin inhibitor or iodoacetic acid, suggests that the F. graminearum protease is an alkaline protease. Farinograph and extensigraph curves showed that the presence of FDK decreased dough consistency and resistance to extension. The presence of FDK in flour resulted in a substantial reduction in loaf volume. The loss of dough functionality and loaf volume potential was attributed to the presence of fungal proteases.
Effects of Degree of Milling, Drying Condition, and Final Moisture Content on Sensory Texture of Cooked Rice
Authors: Lyon Brenda G. , Champagne Elaine T. , Vinyard Bryan T. , Windham William R. , Barton Franklin E. , Webb Bill D. , McClung Anna M. , Moldenhauer Karen A. , Linscombe Steve , McKenzie Kent S. , Kohlwey David E.
Published: June 2007

Different cultures have different preferences for cooked rice flavor and texture characteristics. These differences provide opportunities for U.S. rice varieties to fit into global markets to meet consumer demands worldwide. It is important to assess the properties of U.S. rice varieties and determine the factors that influence their eating quality. Cooked rice texture attributes can be affected by postharvest handling practices, such as degree of milling, drying condition, and final moisture. This article reports the effects of postharvest handling parameters on the texture of cooked medium‐ and short‐grain rice varieties grown in Arkansas (AR) and California (CA), as measured by descriptive sensory analysis. The rice samples were Bengal (AR), Koshihikari (AR), Koshihikari (CA), M‐401 (AR), M‐401 (CA), and M‐202 (CA). The six rice varieties were regular‐ or deepmilled and dried under one of five drying conditions to achieve final moisture levels of 12 or 15% (n = 120). A trained sensory panel developed a lexicon of 16 sensory attributes that described cooked rice texture at different phases of evaluation, beginning with manual adhesiveness and ending with mouthfeel characteristics after swallowing. Rice varieties differed in some physicochemical and sensory properties. Significant differences (P < 0.05) in adhesive properties, such as manual and visual adhesiveness and stickiness to lips, were observed. Rice samples also differed in mouthfeel properties. Factor analysis of sensory data grouped attributes into four groups that explained 68.5% of the variation in data. Primary sensory differences were due to adhesive properties assessed in the early stages of evaluation.
Predicting the Number of Dominant R Alleles in Single Wheat Kernels Using Visible and Near‐Infrared Reflectance Spectra
Authors: Wang D. , Dowell F. E. , Lacey R. E.
Published: June 2007

An optical radiation measurement system was used to measure reflectance spectra of single wheat kernels from 400 to 2,000 nm. A total of 18 wheat samples with 0, 1, 2, or 3 R alleles for red grain color was used for this study. The results indicated a linear relationship between the degree of the red pigmentation and the number of R alleles. The highest coefficient of determination (R2) was 0.78 in the wavelength region of 500–1,700 nm when a four‐class partial least squares model was used. The highest classification of red genes was 78.4%. For two‐class models, differentiating samples with 0 R alleles and 1 R allele from samples with 3 R alleles had the highest success rate of 100 and 98.8%, respectively. The number and combination of R alleles had a significant effect on wheat kernel color. These relationships may be useful to wheat breeders in estimating the number and location of R alleles.
Relaxations Below Glass Transition Temperature in Bread and Its Components
Authors: Roudaut Gaëlle , Maglione Mario , Le Meste Martine
Published: June 2007

Dry glassy bread, cooked gluten, and gelatinized wheat starch‐sucrose mixtures were prepared. Dielectric properties were studied as a function of temperature at different frequencies ranging from 100 to 1,000 kHz. Both bread and starch samples exhibited a tan δ peak at ‐53°C at 10 kHz, which is associated with a secondary relaxation characterized by an activation energy of 50 kJ/mol. The gluten sample did not show any relaxation in the temperature range studied. The magnitude of the relaxation peak was sensitive to the sucrose concentration of the starch sample. The higher the sucrose content, the greater the amplitude of the peak. Such an effect is attributed to a greater β‐relaxation induced by an increasing number of relaxing units or increasing size of the loosely packed regions of the glass. However, it cannot be concluded whether the relaxation is associated with a group present on both starch and sucrose or that the sucrose has an enhancing effect on starch mobility.
Optimization of Fermentation Temperature and Mash Specific Gravity for Fuel Alcohol Production
Authors: Wang S. , Ingledew W. M. , Thomas K. C. , Sosulski K. , Sosulski F. W.
Published: June 2007

The effects of fermentation temperature and dissolved solids concentration adjusted by changing mashing water‐to‐grain ratios on wheat fermentation efficiencies, fermentation times, final ethanol concentrations, and ethanol production rates were studied by using response surface methodology. Final ethanol concentrations in fermentors depended primarily on mash specific gravities. Predictably, increases in fermentation temperatures dramatically reduced fermentation times and thereby shortened fermentation cycles. The highest ethanol production rates were achieved with a high fermentation temperature of 30°C and a low water‐to‐grain ratio of 2.0. At these settings, an ethanol concentration of 13.6% (v/v) was attained with a fermentation time of 54 hr and an ethanol production rate of 2.45 mL of ethanol/L/hr. Optimization of operating conditions suggested in the current study will provide existing fuel alcohol plants with increased productivity without alteration of plant equipment or process flow.
Thermal Expansion of Flour‐Water Dough Measured with a Dynamic Mechanical Analyzer
Authors: Wang F. C. , Sun X. S.
Published: June 2007

Thermal expansion of a wheat flour‐water dough was measured with a dynamic mechanical analyzer (DMA) at a temperature scan range of 25 to 160°C, in 5°C/min increments. Dough water‐absorption levels were increased from 50 to 70% (14% mb) in 4% increments. A standard breadbaking method was used, and loaf volume was measured for regression analysis. The thermal expansion pattern of flour‐water dough during heating included four stages with changes in the thermal expansion coefficient: gas thermal expansion (GTE) (25–60°C), starch gelatinization‐gluten matrix formation (GMF) (60–100°C), vapor pressure expansion (VPE) (100–120°C), and structure fixation‐crust formation (SCF) (>120°C). The onset temperature (To) between each stage and the thermal expansion coefficient (Ce) of each stage were affected significantly by dough water content. The onset temperature () from GTE to GMF (the starting temperature of gelatinization of starch in dough) decreased from 68 to 55°C as water absorption increased from 50 to 70%. The thermal expansion coefficient () of flour‐water dough during GMF was highly correlated (r2 = 0.886) to bread loaf volume. The ratio () of thermal expansion coefficient during the GMF stage to the coefficient during the GTE stage also was significantly correlated (r2 = 0.882) to baking volume. Thus, DMA measurement of dough thermal expansion has the potential to be a powerful method of predicting baking quality in cultivar screenings, baking simulations, and scale‐up studies.
Functional Properties of Cross‐Linked and Hydroxypropylated Waxy Hull‐less Barley Starches
Authors: Zheng G. H. , Han H. L. , Bhatty R. S.
Published: June 2007

Waxy hull‐less barley (HB) starches containing 0 or 5% amylose were cross‐linked with phosphorus oxychloride and the cross‐linked starches were hydroxypropylated with propylene oxide. For comparison, waxy corn and potato starches were similarly modified. For all starches, cross‐linking inhibited granule swelling and prevented swollen granules from disintegration, resulting in dramatic improvement in pasting properties and tolerance to cooking shear and autoclaving. Cross‐linked waxy HB starches were more tolerant to cold storage and cooking shear than cross‐linked waxy corn starch. Hydroxypropylation of the cross‐linked starches reduced granule crystallinity and gelatinization temperature, and improved granule swelling, paste clarity, and freeze‐thaw stability. The double‐modified waxy HB starches showed higher cold tolerance than similarly modified waxy corn and potato starches, as judged by freeze‐thaw stability and clarity after cold storage. These results indicated that the cross‐linked and double‐modified waxy HB starches together may have a wide range of food applications. This study indicated that the behavior of granule swelling and disintegration of swollen granules played an important role in governing paste viscosity, clarity, and freeze‐thaw stability of waxy HB starches.
Amylose and Amylopectin Interact in Retrogradation of Dispersed High‐Amylose Starches
Authors: Klucinec Jeffrey D. , Thompson Donald B.
Published: June 2007

Retrogradation of three high‐amylose starches (HAS: ae du, ae V, and ae VII) and common corn starch (CCS) was examined by dynamic oscillatory rheometry (7.5% [w/w] starch in 20% [v/v] dimethyl sulfoxide [DMSO]), differential scanning calorimetry (DSC; 30% [w/w] starch in water), and turbidity (0.5% [w/w] starch in 20% [v/v] DMSO). Nongranular lipid‐free starch and starch fractions (amylose [AM], amylopectin [AP], and intermediate material [IM]) were studied. Gels were prepared by dispersing starches or fractions in 90% DMSO and diluting with water, followed by storage for seven days at 4°C. For AM from each starch, the elastic modulus (G′) was similar when heated from 6 to 70°C. The G′ of HAS AP gels at 6°C was higher than for CCS AP gels. For nongranular CCS and ae du gels, G′ dropped dramatically (≈100×) when heated from 6 to 70°C, less (≈10×) for ae V gels, and least (≈5×) for ae VII gels. By DSC, each AM endotherm had a peak temperature of ≈140°C, whereas all AP endotherms were complete before 120°C. Endotherms >120°C were not observed for any nongranular starch despite the high AM content of some starches. After cooling starch suspensions from room temperature to 5°C and subsequent rewarming to room temperature, each AM and the ae VII nongranular starch remained highly turbid. Each AP and the remaining nongranular starches lost turbidity during rewarming. Our work suggests that branched molecules of CCS and HAS influence gel properties of nongranular starches by inhibiting or altering AM‐AM interactions.
Extrusion of Wheat Gluten Plasticized with Glycerol: Influence of Process Conditions on Flow Behavior, Rheological Properties, and Molecular Size Distribution
Authors: Redl Andreas , Morel Marie Hélène , Bonicel Joëlle , Vergnes Bruno , Guilbert Stephane
Published: June 2007

Gluten‐glycerol dough was extruded under a variety of processing conditions using a corotating self‐wiping twin‐screw extruder. Influence of feed rate, screw speed, and barrel temperature on processing parameters (die pressure, product temperature, residence time, specific energy) were examined. Use of flow modeling was successful for describing the evolution of the main flow parameters during processing. Rheological properties of extruded samples exhibited network‐like behavior and were characterized and modeled by Cole‐Cole distributions. Changes in molecular sizes of proteins during extrusion were measured by chromatography and appeared to be correlated to molecular size between network strands, as derived from the rheological properties of the materials obtained. Depending on operating conditions, extrudates presented very different surface aspects, ranging from very smooth‐surfaced extrudates with high swell to completely broken extrudates. The results indicated that extrudate breakup was caused by increasing network density, and some gliadins may have acted as cross‐linking agents. Increasing network density resulted in decreasing mobility of polymeric chains, and “protein melt” may no longer have been able to support the strain experienced during extrusion through the die. Increasing network density was reflected in increased plateau modulus and molecular size of protein aggregates. Increasing network structure appeared to be induced by the severity of the thermomechanical treatment, as indicated by specific mechanical energy input and maximum temperature reached.
Separation and Characterization of A‐ and B‐Type Starch Granules in Wheat Endosperm
Authors: Peng M. , Gao M. , Abdel‐Aal E.‐S. M. , Hucl P. , Chibbar R. N.
Published: June 2007

Mature wheat (Triticum aestivum L.) endosperm contains two types of starch granules: large A‐type and small B‐type. Two methods, microsieving or centrifugal sedimentation through aqueous solutions of sucrose, maltose, or Percoll were used to separate A‐ and B‐type starch granules. Microsieving could not completely separate the two types of starch granules, while centrifuging through maltose and sucrose solutions gave a homogenous population for B‐type starch granules only. Centrifuging through two Percoll solutions (70 and 100%, v/v) produced purified populations of both the A‐ and B‐type starch granules. Analysis of starch granule size distribution in the purified A‐ and B‐type granule populations and in the whole‐starch granule population obtained directly from wheat endosperm confirmed that the purified A‐ and B‐type starch granule populations represented their counterparts in mature wheat endosperm. Centrifugations through two Percoll solutions were used to purify A‐ and B‐type starch granule populations from six wheat cultivars. The amylose concentrations and gelatinization properties of these populations were analyzed. All of the A‐type starch granules contained higher amylose concentrations and had higher gelatinization enthalpies than did B‐type starch granules. Although A‐ and B‐type starch granules started to gelatinize at a similar temperature, B‐type starch granules had higher gelatinization peak and completion temperatures than did A‐type starch granules
Effect of Varying Protein Content and Glutenin‐to‐Gliadin Ratio on the Functional Properties of Wheat Dough
Authors: Uthayakumaran S. , Gras P. W. , Stoddard F. L. , Bekes F.
Published: June 2007

Gluten, starch, lipids, and water‐soluble material were separated from seven wheat samples with a range of protein contents and breadmaking quality. The isolated glutens were further partitioned into gliadin‐ and gluteninrich fractions using pH precipitation. Protein content and glutenin‐togliadin ratio were systematically altered by blending these fractions into the original flours in calculated amounts. Mixing properties, extension‐tester parameters, and baking performance of composite flours were determined using small‐scale techniques. Results of dough testing with blends of constant glutenin‐to‐gliadin ratio showed increases in the mixing time, mixograph peak resistance, maximum resistance to extension, extensibility, and loaf volume as the protein content increased. At constant protein content, increases in glutenin‐to‐gliadin ratio were associated with increases in mixing time, mixograph peak resistance, maximum resistance to extension, and loaf volume, and with decreases in extensibility. Thus, total protein content and glutenin‐to‐gliadin ratio independently affected dough and baking properties. The results have allowed the separation of the effects of flour protein quantity and composition on breadmaking properties.
Effect of Drying Temperature on Physicochemical Properties of Starch Isolated from Pasta
Authors: Yue P. , Rayas‐Duarte P. , Elias E.
Published: June 2007

Semolina from four durum wheat genotypes (cvs. Ben, Munich, Rugby, and Vic) were processed into spaghetti that was dried by low (LT), high (HT), and ultrahigh (UHT) temperature drying cycles. Starch was isolated from dried pasta and unprocessed wheat and semolina references. Pasta‐drying cycles had no significant effect on the amylose content of starches. Significant increases in enzyme‐resistant starch were observed in HT‐ and UHT‐dried pasta (2.27 and 2.51%, respectively) compared with LT‐dried pasta (1.68%). Differential scanning calorimetry (DSC) gelatinization characteristics of pasta starches showed a significantly narrow range (Tr), but no changes in onset and peak temperatures (To and Tp, respectively) and gelatinization enthalpy (ΔH1) were observed. When compared with unprocessed reference samples (wheat and semolina), all pasta starches shifted to higher gelatinization To and Tp, with narrow Tr and no changes in δH1. The second endothermic DSC peak indicated no increase in amylose‐lipid complexation (δH2) due to drying cycle. Starches isolated from LT and HT pasta exhibited lower peak viscosities than those from UHT‐dried pasta. Genotypes Ben and Rugby demonstrated higher pasting temperature and lower peak and breakdown viscosities than Vic and Munich.
Deduced Amino Acid Sequence of an α‐Gliadin Gene from Spelt Wheat (Spelta) Includes Sequences Active in Celiac Disease
Authors: Kasarda Donald D. , D'Ovidio Renato
Published: June 2007

The complete amino acid sequence of an α‐type gliadin from spelt wheat (spelta) has been deduced from the cloned DNA sequence and compared with α‐type gliadin sequences from bread wheat. The comparison showed only minor differences in amino acid sequences between the α‐type gliadin from bread wheat and the α‐type gliadin from spelta. The two sequences had an identity of 98.5%. Larger differences can be found between different α‐type gliadin amino acid sequences from common bread wheat. Because all the different classes of gliadins, α, β, γ, and ω, appear to be active in celiac disease, it is reasonably certain that the spelta gliadin is also toxic. We conclude that spelta is not a safe grain for people with celiac disease, contrary to the implications in labeling a bread made from spelta as “an alternative to wheat”. Our conclusions are in accord with spelta and bread wheat being classed taxonomically as subspecies of the same genus and species, Triticum aestivum L.
Predicting Scab, Vomitoxin, and Ergosterol in Single Wheat Kernels Using Near‐Infrared Spectroscopy
Authors: Dowell F. E. , Ram M. S. , Seitz L. M.
Published: June 2007

Near‐infrared spectroscopy (NIRS) was used to detect scab damage and estimate deoxynivalenol (DON) and ergosterol levels in single wheat kernels. Results showed that all scab‐damaged kernels identified by official inspectors were correctly identified by NIRS. In addition, this system identified more kernels with DON than did a visual inspection. DON and ergosterol were predicted with standard errors of ≈40 and 100 ppm, respectively. All samples with visible scab had single kernels with DON levels >120 ppm, and some kernels contained >700 ppm of DON. This technology may provide a means of rapidly screening samples for potential food safety and quality problems related to scab damage.
Functionality of Rice and Sorghum Flours in Baked Tortilla and Corn Chips
Authors: Quintero‐Fuentes X. , McDonough C. M. , Rooney L. W. , Almeida‐Dominguez H.
Published: June 2007

The effects of raw and gelatinized sorghum and rice flours on the structure and texture of baked corn and tortilla chips were evaluated. Dry masa flour was hydrated into masa, sheeted, and cut. Corn chips were baked in an air‐impingement oven, and tortilla chips were baked first in a three‐tier oven and then in an air‐impingement oven. Baked tortilla chips required significantly greater force to break and were less susceptible to breakage during handling than baked corn chips. Raw and gelatinized, normal and waxy rice and sorghum flours significantly changed the texture and structure of baked chips. Waxy rice and sorghum flours reduced peak force and work, increased chip thickness, and improved overall acceptability (as assessed by a taste panel), but waxy rice and sorghum chips were more fragile and had a greater number of large central air cells. Waxy rice was more beneficial than waxy sorghum flour. Gelatinization of waxy flours increased thickness of baked chips, whereas gelatinization of nonwaxy flours had no improvement over waxy flours alone. Gelatinization of sorghum flour significantly decreased the peak force and work values for baked tortilla chips when compared with the control chips. Gelatinized rice flour tortilla chips were not significantly different than the control chips but were significantly harder than the other baked tortilla chips. The complex interactions that occur in baked corn and baked tortilla chips suggest that each ingredient acts differently in the two products. Thus, each ingredient must be evaluated for specific products and processes.
Prediction of Bread Crumb Density by Digital Image Analysis
Authors: Zghal M. C. , Scanlon M. G. , Sapirstein H. D.
Published: June 2007

The cellular structure of bread crumb (crumb grain) is an important factor that contributes to the textural properties of fresh bread. The accuracy of a digital image analysis (DIA) system for crumb grain measurement was evaluated based on its capability to predict bread crumb density from directly computed structural parameters. Bread was prepared from representative flour samples of two different wheat classes, Canada Western Red Spring (CWRS) and Canada Prairie Spring (CPS). Dough mixing and proofing conditions were varied to manipulate loaf volume and crumb density. Sliced bread was subjected to DIA immediately after physical density measurement. Experiments were repeated for the same bread samples after drying to three different moisture contents. Five computed crumb grain parameters were assessed: crumb brightness, cell wall thickness (CWT), void fraction (VF), mean cell area, and crumb fineness (measured as number of cells/cm2). Crumb density ranged from 0.088 to 0.252 g/cm3 depending on proofing and mixing treatments, and was predominantly affected by the former. With increasing crumb density, bread crumb became brighter in appearance, mean cell size and CWT decreased, crumb fineness increased, and the VF decreased. Approximately 80% of the variation in fresh or dried crumb density could be predicted using a linear regression model with two variables, CWT and VF. Results indicated that DIA of directly computed crumb grain could accurately predict bread crumb density after images had been correctly classified into cells and background.
Cholesterol Response and Foam Cell Formation in Hamsters Fed Rice Bran, Oat Bran, and Cellulose + Soy Protein Diets With or Without Added Vitamin E
Authors: Kahlon T. S. , Chow F. I. , Wood D. F.
Published: June 2007

Four‐week‐old male golden Syrian hamsters were fed diets containing cellulose (control, CC), cellulose + soy protein (CS), CS + vitamin E, (CSE), rice bran (RB), RB + vitamin E (RBE), oat bran (OB), and OB + vitamin E (OBE) for six weeks (n = 10/treatment). Diets contained (by weight) 10% total dietary fiber, 3% N, 20% fat, 0.5% cholesterol, and some diets had an additional 0.1% vitamin E. After six weeks, RB and OB diets resulted in significantly higher weight gain than the CC diet. Plasma low‐density lipoprotein cholesterol (LDL‐C) values and the LDL‐C/high‐density lipoprotein cholesterol ratio in hamsters fed CSE, RBE, OB, and OBE diets were significantly lower than in those fed CC diet. There were no significant differences in total plasma cholesterol values among the hamsters fed any of the diets. Liver cholesterol in animals fed OB and OBE diets was significantly lower than in all other groups. Foam cell areas in the inner bend of the aortic arch in animals fed all treatment diets were significantly reduced when compared with that in animals fed CC diet. The level of additional dietary vitamin E did not result in further significant reductions in foam cell area. The results of this study suggest that diets containing rice bran, oat bran, or soy protein significantly reduced the development of atherosclerosis in hypercholesterolemic hamsters.
Physicochemical Properties Related to Quality of Rice Noodles
Authors: Bhattacharya M. , Zee S. Y. , Corke H.
Published: June 2007

Eleven rice genotypes with diverse Rapid Visco Analyzer (RVA) pasting characteristics were evaluated for their physicochemical and gel textural characteristics relative to their suitability for making rice noodles. Apparent amylose content (AC) was highly correlated with swelling power (r = ‐0.65, P < 0.05), flour swelling volume (FSV) (r = ‐0.67, P < 0.05), noodle hardness (r = 0.74, P < 0.01), gumminess (r = 0.82, P < 0.01), chewiness (r = 0.74, P < 0.01), and tensile strength (r = 0.72, P < 0.05). Solubility showed an inverse relationship with the pasting parameters and noodle rehydration, and a positive relationship with cooking loss, noodle hardness, and gumminess. FSV and most of the pasting parameters were negatively correlated with noodle hardness. RVA parameters and textural parameters of gels formed in the RVA canister were well correlated with actual noodle texture and may, therefore, be used for predicting rice noodle quality during early screening of genotypes in breeding programs.
Genetic Diversity in Physical Properties of Starch from a World Collection of Amaranthus
Authors: Wu Huaixiang , Corke Harold
Published: June 2007

Physical and functional properties of starches isolated from 93 noncultivated genotypes of nine Amaranthus species from a world germ plasm collection and an additional 31 cultivated Amaranthus genotypes obtained from China were tested. A wide variation was found in the properties tested among the Amaranthus species and among genotypes within the same species. When comparing starches from cultivated and noncultivated genotypes, it was generally found that amylose was lower; starch pasting profiles were more consistent with higher peak viscosity, lower breakdown, and lower setback; the gelatinization temperature was lower; and energy of enthalpy was higher. Under cool storage, the hardness of cultivated starch pastes was lower and the adhesiveness was higher. As expected, amylose content was a primary factor affecting the physical and functional properties of Amaranthus starch. Compared with reference maize, rice, and wheat starches, Amaranthus starch tended to have lower hot paste viscosity and lower cool paste viscosity; and higher gelatinization temperatures and higher energy of enthalpy. Furthermore, Amaranthus starch pastes showed less change of gel hardness and adhesiveness after cold storage. The environmental effect on the different properties of starch varied among Amaranthus species. It is suggested that Amaranthus starches can be developed for a wide range of food uses.
Reduced‐Oxidized Glutathione Status as a Potential Index of Oxidative Stress in Mature Cereal Grain
Authors: Zenliñski Henryk , Honke Joanna , Troszyñska Agnieszka , Kozłowska Halina
Published: June 2007

The purpose of this study was to examine the reduced and oxidized glutathione status of selected cereal grains as a potential index of balance between oxidative stress and antioxidant systems, and the contribution of reduced glutathione to the total antioxidant status in cereal grain extracts. Wheat cultivars Almari and Henika, barley cultivars Gregor and Mobek, rye cultivar Dañkowskie Złote, oat cultivar Sławko, and buckwheat cultivar Kora were used. Total antioxidant status (TAS) was measured by the ABTS (2,2'‐azinobis(3‐ethyl‐benzothiazoline‐6‐sulphonate)) method. Contents of total phenolic compounds were also determined. Reduced (GSH) and oxidized glutathione (GSSG) (γ‐glutamyl‐cysteinyl‐glycine) were assayed using the spectrofluorimetric method, and results were confirmed by the enzyme recycling method. Correlation coefficient for the GSH/GSSG ratio was r = 0.79. Correlation between TAS and the total phenolic compound content was r = 0.81. Correlation between GSH/GSSG ratio and TAS values was r= 0.46, depending on the extraction system used. The GSH/GSSG ratio may indicate a hierarchy among different cultivars and variance of cereal grains against damage caused by reactive oxygen species. For the main water‐soluble antioxidants, our data indicate a potential hierarchy of resistance in investigated cereals against oxidative stress (buckwheat > wheat > barley ≈ rye > oat). This hierarchy was confirmed by the ability of investigated cereal extracts to scavenge superoxide anion radicals in vitro. The reduced‐oxidized glutathione status in different cereal grains can be applied as a potential index of balance between oxidative stress and antioxidant systems.
Effect of Corn Moisture on the Properties of Pet Food Extrudates
Authors: Mathew J. M. , Hoseney R. C. , Faubion J. M.
Published: June 2007

Corn moisture (9.5–13.5%) was significantly correlated to extrudate properties, even though water was added at the extruder to compensate for the differences in moisture. Water addition was more effective at the preconditioner than at the extruder, and longer retention preconditioner improved expansion. Water added to the pet food formula apparently was absorbed by the other formula ingredients and not the corn. Controlling the specific mechanical energy did not compensate for differences in corn moisture.
Associations of Starch Gel Hardness, Granule Size, Waxy Allelic Expression, Thermal Pasting, Milling Quality, and Kernel Texture of 12 Soft Wheat Cultivars
Authors: Gaines C. S. , Raeker M. Ö. , Tilley M. , Finney P. L. , Wilson J. D. , Bechtel D. B. , Martin R. J. , Seib P. A. , Lookhart G. L. , Donelson T.
Published: June 2007

Starches were isolated from 12 soft wheat (Triticum aestivum L.) cultivars and were characterized for waxy (Wx) allelic expression, thermal pasting characteristics, and starch granule size. Gels were produced from the thermally degraded starches and were evaluated using large deformation rheological measurements. Data were compared with cultivar kernel texture, milling characteristics, starch chemical analyses, and flour pasting characteristics. Larger flour yields were produced from cultivars that had larger starch granules. Flour yield also was correlated with lower amylose content and greater starch content. Harder starch gels were correlated with higher levels of amylose content and softer kernel texture. The cultivar Fillmore, which had a partial waxy mutation at the B locus, produced the highest peak pasting viscosity and the lowest gel hardness. Softer textured wheats had greater lipid‐complexed amylose and starch phosphorus contents and had less total starch content. Among these wheats of the soft market class, softer textured wheats had larger starch granules and harder textured wheats had smaller starch granules. In part, this may explain why soft wheats vary in texture. The smaller granules have larger surface area available for noncovalent bonding with the endosperm protein matrix and they also may pack more efficiently, producing harder endosperm.
Effect of Mill Plate Setting and Number of Dynamic Steeping Stages for an Intermittent Milling and Dynamic Steeping (IMDS) Process for Corn
Authors: Mehra Suhas , Singh Vijay , Tumbleson Michael E. , Eckhoff Steven R.
Published: June 2007

Effect of corn degermination mill parameters (clearance between mill plates and rpm) were assessed on the broken germ and number of whole kernels in mash so as to optimize the cracking procedure for the intermittent milling and dynamic steeping (IMDS) process. The dynamic steep time and number of intermittent milling stages for the IMDS process were also optimized for maximum starch recovery. A comparison was made between the IMDS and the conventional steeping process for fraction yields. A clearance of 0.45–0.48 cm between the plates gave the most optimum processing conditions (minimum broken germ and least amount of whole kernels in mash after cracking). Effect of rpm on germ damage and kernel cracking was not significant when optimum clearance between the degermination plates was maintained. Two stages of intermittent milling with a dynamic steep time of 30 min or higher was recommended because it produced the highest yield of starch and germ. Comparison of the IMDS process with the conventional wet‐milling process showed that starch and gluten yield increased by 1.6 and 4.26%, respectively, in the IMDS process. Germ recovered from the IMDS process was 0.54% lower than that from the conventional steeping process.
Relationships Among Grain Hardness, Pentosan Fractions, and End‐Use Quality of Wheat
Authors: Bettge A. D. , Morris Craig F.
Published: June 2007

Grain texture (hardness) in wheat (Triticum aestivum L.) is a major determinant of end‐usage. Variation in grain texture can be conceptually assigned to the two major hardness classes that result from the action of one major gene (Hardness) or to as‐yet undetermined factors contributing to residual variation within hardness classes. Identifying the physicochemical basis of both sources of texture variation could provide a means of better controlling or manipulating this quality trait. Pursuant to this objective, the role of pentosans was examined. Pentosan fractions (membrane‐associated, total, and soluble) were isolated from 13 hard and 13 soft wheat samples and their flours. Among the hard wheat samples, pentosans had a minimal role in modifying grain hardness. However, among the soft wheat samples, pentosans appeared to have a significant hardness‐modifying effect that carried over into end‐use quality. Among the soft wheat samples, pentosan fractions, along with wheat protein, accounted for 53–76% of the variation in grain texture, depending on the method used to quantify texture. Membrane‐associated pentosans were the most influential single parameter in modeling grain texture for the soft wheat samples. Membrane‐associated pentosans were most influential in accounting for variation (69%) in alkaline water retention capacity. Total pentosans, together with flour protein, accounted for 87% of the variation in cookie diameter for soft wheat samples, with the total pentosan fraction being the more influential.
Grouping and Identification of Argentine Maize Races by Principal Component Analysis of Zein Reversed‐Phase HPLC Data
Authors: Robutti J. L. , Borrás F. S. , Ferrer M. E. , Bietz J. A.
Published: June 2007

Racial classification of maize has important taxonomic and phylogenetic implications. It may also serve to organize germ plasm inventory, thus helping breeders choose their stocks. Maize racial classification is usually based on phenotypic descriptors, which may not always accurately express genetic characteristics. In contrast, synthesis and expression of zeins is directly associated with genotype. This study was conducted to determine whether racial grouping and identification of maize can be done by applying principal component analysis to zein reversed‐phase high‐performance liquid chromatography (RP‐HPLC) data. Zeins from samples of 97 landraces (primitive varieties) of the Argentine races Cristalino Colorado, Dentado Blanco, Avatí Morotí, Capia, and Pisingallo, stored at the Pergamino Active Maize Germplasm Bank, were analyzed by RP‐HPLC. Data from the ≈21‐ to 53‐min chromatogram region (total zeins [ZT]), the ≈21‐ to‐30 min region (zeins 2 [Z2]), or the ≈38‐ to 52‐ min region (zeins 1 [Z1]) were subjected to multivariate analysis based on principal component to group samples by race and to assign unknown samples to predetermined racial groups. Clearly differentiated racial groups were revealed, closely matching groups based on phenotype. Unknown samples could be assigned, with a low percentage of misidentification, to predetermined groups based on Mahalanobis distances. The shortest distances of unknown samples were almost always the distances to their respective groups. Approaches other than multivariate analysis were used to group and assign samples to defined races but they were not as effective. Results indicate the potential of this method as a complementary tool to perform racial grouping and identify maize materials with high genetic variability.
Cross‐Linking of Wheat Gluten Using a Water‐Soluble Carbodiimide
Authors: Tropini V. , Lens J.‐P. , Mulder W. J. , Silvestre F.
Published: June 2007

Wheat gluten was cross‐linked using water‐soluble 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide HCl (EDC). To enhance cross‐linking, N‐hydroxysuccinimide (NHS) was added to the reaction mixture. The cross‐linking efficiency was evaluated by the decrease in the amount of amino groups, the solubility of the protein in aqueous solutions with different pH levels, and by the change in the molecular weight distribution of the cross‐linked compounds. Cross‐linking was dependent on the reaction time, the molar ratio of added reactants, and the pH level of the reaction mixture. If the reaction was carried out at pH 3, no decrease in the amount of amino groups or solubility was observed. At pH 5–7, the amount of amino groups decreased from 15 to 10 mmol/100 g of protein. This was accompanied by a large decrease in the water solubility of the protein (<10%, w/v). Finally, reaction at pH 11 decreased the amount of amino groups from 15 to 8 mmol/100 g of protein. However, hardly any decrease in the water solubility was observed. Based on these results and SDS‐PAGE experiments, two cross‐link mechanisms are suggested: one resulting in inter‐ and the other resulting in intramolecular cross‐links.
Laboratory Procedure to Wet‐Mill 100 g of Grain Sorghum into Six Fractions
Authors: Xie X. J. , Seib P. A.
Published: June 2007

A small‐scale (100 g of grain) procedure was developed to wet‐mill grain sorghum into six fractions by modifying the procedure of Eckhoff et al (1996). The wet‐milling process was repeated five times on commercial grain sorghum, and the mean yield (69.4%) of starch (≤0.3% protein) varied by 0.3%, whereas the yields of fiber, gluten, and germ plus bran fractions varied by 5–6%. The starch fraction accounted for ≈95% of that in the grain, while the total solids recovered was 99.0%. Four other samples of grain sorghum gave 92–95% recoveries of starches and 98.2–99.8% recoveries of total solids. All grain sorghum starches had lightness (L*) values and pasting curves nearly equal to those of a commercial maize starch.
Description of a Micromill with Instrumentation for Measuring Grinding Characteristics of Wheat Grain
Authors: Pujol R. , Létang C. , Lempereur I. , Chaurand M. , Mabille F. , Abecassis J.
Published: June 2007

A new method for characterizing the grinding characteristics of wheat grain is described. A micromill was designed for this purpose and equipped with on‐line torque transducers to obtain accurate measurements of mechanical energy consumption during milling. This micromill can be used for testing the milling performance of small quantities of grain (100 g). It can distinguish between different types of wheat grain (soft wheat, hard wheat, durum wheat) on the basis of total specific energy during milling. Wheat characterization can be enhanced by taking particle sizes of the milled products into account. A milling index based on energy consumption and particle size reduction was developed to characterize wheat behavior during milling. This index had a high discriminatory potential, ranging from 100 kJ/kg for soft wheat flour to 600 kJ/kg for durum wheat flour. This micromill directly measures the grinding resistance of wheat kernels as a function of both the kernel hardness and vitreousness, contrary to standard kernel hardness measurements obtained by particle size index and near‐infrared reflectance analysis techniques that only reflect the fracture mode (fine particle reduction potential).