bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Behavior of Zein Sheets Plasticized with Oleic Acid
Authors: Santosa F. X. Budi , Padua Graciela Wild
Published: June 2007

Zein, extracted from underutilized corn gluten meal may serve as an alternative starting material for fabrication of biodegradable packaging. Zein plasticized with oleic acid may be formed into flexible and water‐resistant sheets. Our objective was to investigate the effect of plasticization on thermal behavior of zein sheets employing differential scanning calorimetry (DSC). Zein sheets were rolled from a resin prepared by dispersing zein and oleic acid in aqueous alcohol followed by the recovery of the formed moldable compound by precipitation with water. Sheets were later replasticized with additional oleic acid to increase ductility. DSC thermograms were used to investigate zein‐oleic acid interactions in zein sheets. DSC endotherms were attributed to melting of free oleic acid or to the dissociation of zein‐oleic acid bonds. Plasticized sheets contained bound and free oleic acid. Further heat‐treatment of plasticized sheets apparently resulted in zein absorption of free oleic acid. However, high temperatures were believed to cause dissociation of some zein‐oleic acid bonds formed during replasticization.
Effect of Broken Corn Levels on Water Absorption and Steepwater Characteristics
Authors: Wang D. , Eckhoff S. R.
Published: June 2007

Broken corn created by grounding sound corn kernels was added back at levels of 0, 4, 8, 12, or 16%, by weight, to whole kernels of three corresponding hybrids: FR27 × FRMo17 (a soft endosperm corn), FR618 × FR600 (amedium‐hard endosperm corn), and FR618 × LH123 (a hard endosperm corn). The samples had been dried from 28% moisture content to 15% moisture content either by using ambient air at ≈25°C or at 110°C. Samples were steeped for 36 hr at 52°C in 0.15% sulfur dioxide and 0.5% lactic acid steeping solution. The steepwater characteristics, such as water absorption, solids and protein content in the steepwater, and steepwater pH, were measured by periodic sampling and analyzed. Broken corn level has a significant effect on the amount of solids released during steeping and steepwater protein content for all samples. Both steepwater solids and protein content increased linearly as broken corn content increased. Corn drying temperature, kernel hardness, and interactions between drying temperature and kernel hardness has a significant effect on steepwater solids and protein content and steepwater pH in both broken and unbroken corn. Corn dried at low temperature released more soluble solids and protein into the steepwater than corn dried at high temperature. Soft endosperm and medium‐hard endosperm corn released more soluble solids and protein into the steepwater than hard endosperm corn. Soft endosperm corn resulted in a higher steepwater pH than medium‐hard and hard endosperm corn. No significant effect of broken corn content on final moisture content of steeped corn and steepwater pH was observed.
Effect of Moisture Content and Temperature on Respiration Rate of Rice
Authors: Dillahunty A. L. , Siebenmorgen T. J. , Buescher R. W. , Smith D. E. , Mauromoustakos A.
Published: June 2007

One cause of yellowing or stackburn of rice may be elevated respiration rates caused by storage at either high moisture content (MC) or temperature. The effect of MC and temperature on the respiration rate of Oryza sativa L. ‘Bengal’ and ‘Cypress’ rice harvested in the fall of 1998 was investigated. For respiration rate measurement of rough rice at different temperatures, rice samples at high, medium, and low MC were sealed in quart jars and equilibrated to temperatures of 20–80°C. The respiration rate was quantified by measuring the rate of CO2 accumulation in the free air space. To determine the effect of MC on respiration rate, rough rice was tested at 12–25% MC. Respiration was greatly affected by MC and temperature. The response of respiration to temperature was dependent on MC and varied between rice cultivars. Respiration rates increased as MC increased from ≈15 to 25%. Maximum respiration was at 50°C when MC was high (20–25%). At 15% MC, respiration increased from 20 to 70°C, while respiration of 12% MC rice, although very low, appeared to increase up to 80°C. A model was developed from this data to predict the respiration rate of rice over the MC range tested.
Influence of Annealing on Gel Properties of Mung Bean Starch
Authors: Chung Koo Min , Moon Tae Wha , Chun Jae Kun
Published: June 2007

Mung bean starch gels (8% solids) were prepared after annealing at 45–60°C for 1–24 hr, and the relationship between the physical properties of gels and the swelling power (SP) and solubility of starch was investigated. The SP and solubility decreased with increasing annealing temperature and time, mostly in the first 6 hr. The solubles were mainly composed of amylose. Gel hardness at a 5 mm depth of annealed starch was larger than that of native starch, and gel hardness increased as SP decreased (r = ‐0.94). Upon continued compression, the yield force of gel showed a different function. Above SP of ≈12.5, the yield force of annealed starch gels decreased, but at <12.5 the yield force increased with increasing SP. Both granular rigidity and extent of packing appeared to determine the yield force. Although annealing increased the gel hardness, α‐amylase digestibility of gel was not affected. Pasting analysis in the Rapid Visco Analyser (RVA) revealed that annealing increased pasting temperature. A pasting peak was found only in 45 and 50°C annealed starches. Overall paste viscosities of the starches annealed at >55°C were lower than that of the control starch. Final viscosities in RVA were correlated with the yield force of gel (r = 0.99).
Modeling of Water Sorption Kinetics in Spaghetti During Overcooking
Authors: Del Nobile M. A. , Massera M.
Published: June 2007

The organoleptic changes of pasta during overcooking are strongly related to the rate at which water molecules penetrate the pasta matrix once the optimal cooking conditions are reached. A model to describe water sorption kinetics during the overcooking stage is presented. The model has been developed assuming that overcooking starts once the central core disappears and that during this stage sorption kinetics are governed by the pasta matrix relaxation rate. To validate the model, water sorption tests were performed at 10–100°C. A good agreement between the model predictions and the experimental data was obtained. Based on these results, the main matrix relaxation time can be used to compare behavior during overcooking of pastas with different compositional and technological variables.
Chalky and Translucent Rice Grains Differ in Starch Composition and Structure and Cooking Properties
Authors: Lisle A. J. , Martin M. , Fitzgerald M. A.
Published: June 2007

Chalk is an important quality characteristic in rice and occurs most commonly when high temperatures are experienced during grain development. The aims of this report are to determine whether chalk affects cooking quality and to attempt to explain the effects on the basis of starch and protein in chalky and translucent grains. Three cultivars of rice were grown in the glasshouse at either 38/21°C or 26/15°C (day/night temperatures). Rice grown at the higher temperature contained more chalky grains. Grains in the inferior position were more susceptible to forming chalk than were those in the superior position. The presence or absence of chalk affected cooking quality but neither amylose content, amylopectin structure nor protein composition explained the differences in cooking quality. However, the shape, size, and packing of amyloplasts and cells in chalky grains differed from those in translucent grains and might offer an explanation for the differences in cooking quality. It seems likely that the processes involved in the initiation or packing of amyloplasts are susceptible to high temperatures.
Optimized Methods for Incorporating Glutenin Subunits into Wheat Dough for Extension and Baking Studies
Authors: Uthayakumaran S. , Stoddard F. L. , Gras P. W. , Bekes F.
Published: June 2007

In order to study the functional properties of glutenin subunits added to a dough, they must be incorporated into the glutenin polymer. This requires partial reduction to open up the polymer, followed by oxidation to incorporate the added monomer into the polymer. Existing methods for incorporating glutenin subunits were suitable only for studies on mixing properties and needed to be modified for use in studies on extension and baking. A range of concentrations and of reaction times was therefore tested for both the reductant and the oxidant. In addition, mixing time as well as relaxation time before extension were varied. Extension curves and loaf heights were used to evaluate the treatments. Optimum conditions were developed that provided extension curves of normal dimensions but with altered shape. The conditions were reduction with 0.2 mg/mL of dithiothreitol (DTT) solution for 1 min followed by oxidation with 5 mg/mL of KIO3 solution, then mixing the dough to 70% of the peak dough development time. For microbaking, the conditions of 2 mg/mL of DTT for 1 min, 2.5 mg/mL of KIO3 for 5 min, and mixing the dough to peak development time allowed loaf height to be retained. The size distribution of the glutenin polymer was analyzed using size‐exclusion HPLC and field‐flow fractionation methods. This showed that the monomers were incorporated into the polymer and that polymer size was restored to control levels following reduction and oxidation.
Basic Rheology of Bread Dough with Modified Protein Content and Glutenin‐to‐Gliadin Ratios
Authors: Uthayakumaran S. , Newberry M. , Keentok M. , Stoddard F. L. , Bekes F.
Published: June 2007

The uniaxial elongational and shear rheology of doughs varying in either the protein content or glutenin‐to‐gliadin ratio were investigated. Increasing the protein content at constant glutenin‐to‐gliadin ratio increased the strain‐hardening properties of the dough, as shown by increasing elongational rupture viscosity and rupture stress. Glutenin and gliadin had a more complex effect on the elongational properties of the dough. Increased levels of glutenin increased the rupture viscosity but lowered the rupture strain, while elevated gliadin levels lowered the rupture viscosity but increased the rupture strain. These observations provide rheological support for the widely inferred role of gliadin and glutenin in shaping bread dough rheology, namely that gliadin contributes the flow properties, and glutenin contributes the elastic or strength properties. The shear and elongational properties of the doughs were quite different, reflecting the dissimilar natures of these two types of flow. Increasing protein content lowered the maximum shear viscosity, while increasing the glutenin‐to‐gliadin ratio increased maximum shear viscosity. Strong correlations between the results of basic and empirical rheology were found. These basic, or fundamental, rheological measurements confirmed prior empirical studies and supported baking industry experience, highlighting the potential of basic rheology for bread and wheat research.
Comparison of Asian Noodles from Some Hard White and Hard Red Wheat Flours
Authors: Seib P. A. , Liang X. , Guan F. , Liang Y. T. , Yang H. C.
Published: June 2007

Asian noodles were prepared by an objective laboratory method that included adding optimum water to the dry ingredients, mixing the ingredients to homogeneous salt distribution, and sheeting of the dough under low shear stress. The lightness (L*) values of alkaline‐ and salt‐noodle doughs made from 65% extraction hard white wheat flours (except KS96HW115 flour at ≈70% extraction) were higher than those from 60% extraction hard red wheat flours (except Karl 92 flour at ≈70% extraction). A hard white spring wheat, ID377s, and a Kansas line of hard white winter wheat, KS96HW115, to be released in 2000, gave the highest L* values for dough sheets stored for 2 and 24 hr at 25°C. Cooking losses were 5–9 percentage points higher for alkaline noodles than salt noodles, but the cooking yields of the two types of Asian noodles were almost the same. Cooked alkaline noodles made from a high‐swelling flour (SP93≈21 g/g) gave higher tensile strength than those made from several low‐swelling flours (SP93 ≈15 g/g) with the same protein contents (≈12.5%). However, the cooked salt noodles gave the same tensile strength.
Effects of Laccase and Ferulic Acid on Wheat Flour Doughs
Authors: Labat E. , Morel M. H. , Rouau X.
Published: June 2007

The effects of a laccase from the fungus Pycnoporus cinnabarinus on the mixing of a wheat flour dough with or without added ferulic acid (FA) were studied. Laccase reduced dough time‐to‐peak and accelerated dough breakdown in comparison with the control. Its effect was enhanced with FA. The water extractability of arabinoxylans (AX) increased during mixing of a dough free of added laccase, especially with exogenous FA. At the same time, the extractability of FA decreased during mixing. Added FA may have competed with endogenous AX feruloyl esters, inhibiting partly oxidative gelation. Laccase decreased AX extractability by chain cross‐linking through oxidative dimerization of feruloyl esters. FA and, moreover, FA plus laccase, increased the oxidation of sulfhydryl (SH) groups. FA and, even more, FA in combination with laccase, increased the rate of protein depolymerization during mixing. FA and the products of FA laccase oxidation participated in a redox reaction involving SH groups. A coupling reaction involving enzymatically generated feruloyl radicals and thiol radicals generated through the mechanical breakdown of inter‐chain disulfide bonds might explain these results.
Effects of Flour Strength, Baking Absorption, and Processing Conditions on the Structure and Mechanical Properties of Bread Crumb
Authors: Zghal M. C. , Scanlon M. G. , Sapirstein H. D.
Published: June 2007

The objective of this study was to determine the effects of flour type, baking absorption, variation in sheeting, and dough proofing time on the density, crumb grain (visual texture), and mechanical properties (physical texture) of bread crumb. All response variables were measured on the same bread crumb specimens. Bread loaves were prepared by a short‐time bread‐making process using four spring wheat flours of varying strength. After crumb density measurement, digital image analysis (DIA) was used to determine crumb grain properties including crumb brightness, cell size, cell wall thickness, and crumb uniformity. Tensile tests were performed on bone‐shaped specimens cut from the same bread slices used for DIA to obtain values for Young's modulus, fracture stress, fracture strain, and fracture energy. Proof time had the most profound influence on the bread with substantial effects on loaf volume, crumb density, crumb brightness, and grain, as well as crumb mechanical properties. Increasing proof time resulted in higher loaf volume, lower crumb density and brightness, coarser crumb with fewer and larger cells with thicker cell walls, and weaker crumb tensile properties. Varying flour type also led to significant differences in most of the measured crumb parameters that appeared to correspond to differences in gluten strength among the flour samples. With increasing flour strength, there was a clear trend to increasing loaf volume, finer and more uniform crumb grain, and stronger and more extensible bread crumb. Increasing baking absorption had virtually no effect on crumb structure but significantly weakened crumb strength and increased fracture strain. In contrast, varying the number of sheeting passes had a minor effect on crumb cellular structure but no effect on mechanical properties. The experimental data were consistent with a cause‐effect relationship between flour strength and the tensile strength of bread crumb arising as a result of stronger flours exhibiting greater resistance to gas cell coalescence, thereby having fewer crumb defects.
Creep‐Recovery of Bread and Correlation to Sensory Measurements of Textural Attributes
Authors: Carson Lin , Sun Xiuzhi S.
Published: June 2007

Bread crumb firmness has been studied extensively with many instruments. Other texture attributes like springiness, cohesiveness, and adhesiveness can be obtained through sensory analysis or by texture analysis using texture profile analysis. In this study, mechanical analysis (MA) was used to study the creep‐recovery of several commercial breads. A descriptive panel was used to analyze these attributes and the results were correlated to MA measurements. With use of a small probe force in the linear viscoelastic portion (50 mN), bread sensory firmness was correlated quadratically to MA creep deformation (r2 = 0.77) and sensory springiness was correlated quadratically to the combination of MA recovery percentage and its rate (r2 = 0.82). With use of a large probe force in the nonlinear viscoelastic portion (600 mN), bread cohesiveness was correlated linearly to the MA recovery percentage (r2 = 0.98). These results indicate that the creep‐recovery test can be used to determine some texture attributes of bread crumb.
Characterization of Oat Endoproteinases that Hydrolyze Oat Avenins
Authors: Mikola Markku , Brinck Outi , Jones Berne L.
Published: June 2007

During oat seed germination, the insoluble storage proteins must be solubilized and transported to the embryo for use by the developing plantlet. We showed earlier that pH 6.2 active serine and metalloproteinases were the predominant gelatin‐hydrolyzing enzymes of oats, while the oat globulins were degraded by pH 3.8 active cysteine proteases. The pH of the endosperms of germinating oats is 6.2. We have continued our characterization of the germinated oat proteinases by determining which hydrolyze avenins, the oat storage prolamins. Avenins of resting seeds were purified and hydrolyzed with proteinases that were extracted from oat seeds that were germinated for various periods. The peptides released were analyzed using SDS‐PAGE. The α‐avenins were hydrolyzed at pH 3.8 by cysteine proteinases from four‐day germinated seeds and the β‐avenins were hydrolyzed by similar enzymes from eight‐day germinated seeds. At pH 6.2 or pH 5.0, the avenins were not degraded by any of the germinated oats endoproteinases. It is probable that some kind of pH compartmentalization occurs within germinating oat seed. After four days of germination, either new proteinases form or some preexisting proteinases are activated. The cysteine proteinases are apparently responsible for the majority of the storage protein hydrolysis that occurs during oat germination.
Influence of High Molecular Weight (HMW) and Low Molecular Weight (LMW) Glutenin Subunits Controlled by Glu‐1 and Glu‐3 Loci on Durum Wheat Quality
Authors: Brites C. , Carrillo J. M.
Published: June 2007

The progenies of four intervarietal durum wheat crosses were used to determine the effects of glutenin variants coded at Glu‐1 and Glu‐3 loci on durum wheat quality properties. The F2 lines were analyzed for high molecular weight (HMW) and low molecular weight (LMW) glutenin composition by electrophoresis. Whole grain derived F3 and F4 samples were analyzed for vitreousness, protein, and dry gluten contents, gluten index, SDS sedimentation volume, mixograph, and alveograph properties. Allelic variation at the Glu‐B1 and Glu‐B3 loci affected gluten quality significantly. Comparisons among the Glu‐B3 and Glu‐B1 loci indicated that the LMW glutenin subunits controlled by Glu‐B3 c and j made the largest positive contribution, followed by the alleles a, k, and b. HMW glutenin subunits 14+15 gave larger SDS values and higher mixing development times than subunits 7+8 and 20. The positive effects of the glutenin subunits LMW c and HMW 14+15 were additive. Flour protein content, vitreousness, and mixograph peak height values were positively correlated with each other as well as with Dglut values, whereas the SDS sedimentation highly correlated with mixing development time, alveograph strength, and extensibility but was not correlated with the other parameters. The results of quality analysis, together with the results of the genetic analysis, led to the conclusion that SDS sedimentation, mixograph mixing development time, and peak breakdown are the tests more influenced by allelic variation of prolamin. The uses of the results in durum wheat quality breeding programs are discussed.
Effect of Multiple Substitution of Glutenin and Gliadin Proteins on Flour Quality of Canada Prairie Spring Wheat
Authors: Wesley A. S. , Lukow O. M. , McKenzie R. I. H. , Ames N. , Brown D.
Published: June 2007

The effect of genetic substitution of two to four glutenin and gliadin subunits from a Canada Prairie Spring (CPS) cv. Biggar BSR into Alpha 16, another CPS wheat line, was studied for rheological and baking quality. Results from double substitution showed that the presence of a gliadin component from Biggar BSR (BGGL) and low molecular weight glutenin subunit 45 (LMW 45) contributed to improved dough strength characteristics. Presence of BGGL in combination with high molecular weight glutenin subunit 1 (HMW 1) or 17+18 (HMW 17+18) also showed improved dough strength over control Alpha lines. When three or four protein subunits were substituted, even though improved quality performance was observed, it was associated with the negative effect of lowered flour water absorptions in spite of similar protein contents. The study confirms that LMW glutenins, as well as gliadins, play an important role along with HMW glutenins in wheat flour quality. CPS wheat lines with improved dough strength properties can be selected from the double substitution lines with the combination of BGGL/LMW 45 and BGGL/HMW 1.
Reoxidation Behavior of Wheat and Rye Glutelin Subunits
Authors: Antes Susanne , Wieser Herbert
Published: June 2007

The ability of HMW and LMW subunits of wheat glutelin to form a polymeric gluten network by intermolecular disulfide bonds is responsible for the unique rheological properties and baking quality of wheat dough. Because the mechanism of gluten formation is not fully understood, the reoxidation behavior of HMW and LMW subunits of wheat glutelin and HMW subunits of rye glutelin was studied. The subunits were isolated from wheat flour cv. Rektor (REK) and from rye flour cv. Danko (DAN) with a selective extraction and precipitation method. For reoxidation, different oxidants (KBrO3 and KIO3), protein concentrations (0.5, 1.0, and 2.0%), solvent compositions, pH values (2.0 and 8.0), and reaction times (0–360 min) were compared. The characterization of reoxidized products was achieved by the determination of the thiol content with the Ellman's reagent, and of the Mr distribution by gel‐permeation chromatography. The results demonstrated that both HMW and LMW subunits could be slowly reoxidized with KBrO3 to polymers with Mr up to several millions. Yield and Mr distribution of polymers were dependent both on the protein concentration and on the molar ratio of oxidants to thiol groups. The HMW subunits of wheat glutelin (HMW‐REK) yielded slightly higher quantities of polymeric proteins than did the HMW subunits of rye (HMW‐DAN). Reoxidation with KIO3 proceeded much faster than with KBrO3 and led to lower proportions of polymerized proteins for HMW‐REK and HMW‐DAN. Obviously, more intra‐ and fewer intermolecular disulfide bonds were formed by reoxidation with KIO3 compared with KBrO3. In contrast, LMW‐REK was reoxidized with KIO3 to higher amounts of polymeric aggregates, which indicated that LMW subunits formed intermolecular disulfide bonds with both KIO3 and KBrO3. Independent of the protein type and the oxidant used for reoxidation, more inter‐ and fewer intramolecular disulfide bonds were formed when the protein concentration was increased. Single subunits 5, 7, and 10 were isolated from HMW‐REK by preparative acid‐PAGE and were reoxidized with KBrO3 for 360 min. The Mr distribution indicated that x‐type subunit 5 had a greater tendency to form polymers than x‐type subunit 7. The y‐type subunit 10 was characterized by a lower proportion of polymers after reoxidation than x‐type subunits 5 and 7.
Development of Predictive Models for Optimization of Phytate Degradation in Wheat and Rye During Hydrothermal Processing
Authors: Bergman E.‐L. , Fredlund K. , Reinikainen P. , Sandberg A.‐S.
Published: June 2007

Whole kernels of wheat (Triticum aestivum ‘Kosack’), rye (Secale cereale ‘Motto’) and rice (Oryza sativa) were hydrothermally treated to reduce the phytate content. The hydrothermal processes used in this study included alternating wet and dry steeping periods. Two hydrothermal processes were used for wheat and rye with two and three wet and dry steeping steps, respectively. The process using two wet and dry steeping steps (process 1) was optimized for phytate reduction with respect to temperature during the process and lactic acid concentration used in the wet steeping steps. Optimal conditions for phytate breakdown in wheat and rye in process 1 were 55°C during the whole process and 1.3–1.5% lactic acid solution as the soaking agent in the wet steeping periods for wheat and 1.3% for rye. The hydrothermal process with three wet and dry steeping periods for wheat and rye (process 2) showed that the temperature used in the third wet and dry steeps did not significantly influence (P > 0.05) the phytate reduction in wheat and rye during these steps. The maximal phytate reduction was 94.4–95.6% in wheat and 99.0–99.5% in rye during hydrothermal processing. In rice, hydrothermal processing resulted, at best, in a 99.8% phytate reduction.
Effect of Milling Ratio on Sensory Properties of Cooked Rice and on Physicochemical Properties of Milled and Cooked Rice
Authors: Park Jung Kwang , Kim Sang Sook , Kim Kwang Ok
Published: June 2007

Quantitative descriptive analysis of cooked rice was performed to investigate the effect of milling ratios (≈8.0–14.0%, based on brown rice) on sensory characteristics of cooked rice, in relation to physicochemical characteristics of milled rice and cooked rice. The proximate composition of uncooked rice decreased with increased milling while whiteness increased. The initial pasting temperature of rice flour decreased with increased milling while peak, breakdown, and setback viscosities increased. The instrumental texture profile of cooked rice revealed that hardness and chewiness decreased with increased milling while adhesiveness increased. A trained panel found that color, intactness of grains, puffed corn flavor, raw rice flavor, wet cardboard flavor, hay‐like flavor, and bitter taste were lower while glossiness, plumpness, and sweet taste were higher with increased milling. Degree of agglomeration, adhesiveness, cohesiveness of mass, inner moisture, and toothpacking of cooked rice increased while hardness and chewiness decreased with increased milling. Sensory analysis of cooked rice was more discriminating than instrumental texture profile analysis in terms of hardness, adhesiveness, and cohesiveness. There were high negative correlations between descriptive attributes of sweet taste, degree of agglomeration, adhesiveness, cohesiveness of mass, and moisture (r = −0.94 to −0.87), protein (r = −0.96 to −0.83), and fat contents (r = −0.91 to −0.85). Instrumental hardness showed high correlation with sensory hardness (r = 0.80).
Milling—A Further Parameter Affecting the Rapid Visco Analyser (RVA) Profile
Authors: Becker A. , Hill S. E. , Mitchell J. R.
Published: June 2007

Rapid Visco Analyser (RVA) profiles were recorded for raw maize grits and two extruded nonexpanded pellets based on wheat and maize. Large differences were found between the profiles obtained when an impeller mill was used to prepare the samples compared with a disk mill. The differences were related to differences in particle properties of the ground products (particle‐size distribution, particle shape, and protein content). Generally, milling the samples with the impeller mill resulted in greater starch conversion than with a disk mill. For raw maize grits, this was shown by X‐ray diffraction, differential scanning calorimetry (DSC), and alkaline viscosity measurements. Several other laboratory mills were tested and all produced particulates with a sieve range of 125–212 μm that had substantially differing RVA profiles. Cooling the sample during milling did not nullify the milling effects. All the laboratory mills produced <20% of the particulates of the size range required for the RVA analysis. The mill used for sample preparation can exert a significant effect on the RVA for both raw and processed cereal samples, even if measurements are made on a defined sieve fraction.
Location of Sites of Reaction Within Starch Granules
Authors: Huber Kerry C. , BeMiller James N.
Published: June 2007

To observe granular reaction patterns within modified starch granules, starch derivatives were converted to thallium(I) salts and viewed by scanning electron microscopy compositional backscattered electron imaging. Observation of phosphorylated potato and sorghum starches and a hydroxypropyl analog of waxy maize starch revealed that granular patterns of reaction were influenced by both starch and reagent types. In waxy maize and sorghum starches, flow of reagent into the granule matrix occurred from channels (laterally) and cavities (from the inside outward). In potato starch granules, which do not possess channels, reagent diffused inward through exterior granule surfaces. Phosphoryl chloride (highly reactive) reacted to a large extent at granule surfaces, while the propylene oxide analog (less reactive) appeared to diffuse into the granule matrix prior to reacting.
Effect of l‐Cysteine on the Rheological Properties of Wheat Flour
Authors: Lambert Ian A. , Kokini Jozef L.
Published: June 2007

Extrudate expansion of cereal‐based products is largely dependent on the molecular interactions and structural transformations that proteins undergo during extrusion processing. Such changes strongly influence the characteristic rheological properties of the melt. It is possible to modify rheological properties of wheat flour during extrusion processing, in particular shear viscosity, with cysteine. The objective of this work was to further develop an understanding of the molecular interactions and structural transformations of wheat flour from dynamic oscillatory rheological measurements. Temperature and frequency sweeps were conducted in the linear viscoelastic range of the material. Changes in the storage modulus (G′), the loss modulus (G″) and the loss tangent (tan δ) of 25% moisture wheat flour disks as a function of cysteine concentration (0–0.75%) were monitored. Molecular weight between cross‐links (Mc) and the number of cross‐links (Nc) per glutenin molecule were determined from frequency sweep data. Increasing cysteine concentration broke cross‐links by decreasing G′ maximum and increasing tan δ values. Molecular weight between cross‐links increased and the number of cross‐links decreased. G′ values from temperature sweeps showed a similar trend. This information leads to a better understanding of the viscoelastic behavior of wheat flour doughs during extrusion cooking and elucidation of protein‐protein reaction mechanisms and other interactions in extruded cereal‐based snack foods.
Application of Oat Oil in Breadbaking
Authors: Erazo‐Castrejón Sofía V. , Doehlert Douglas C. , D'Appolonia Bert L.
Published: June 2007

Lipids, especially polar lipids, can improve loaf volume, grain and texture, and delay staling in bread. Oats (Avena sativa L.) are rich in total and polar lipids. We have investigated the effect of oat lipids in a bread formulation on loaf volume, appearance, and bread staling. Oat oil was fractionated into polar and nonpolar fractions by water‐degumming. Crude oat oil and shortening (at 3%) increased loaf volume by ≈11% over the zero lipid formulation. The polar lipid fraction increased loaf volume by nearly the same amount when added at only a 0.5% level. The addition of 3% crude oat oil or 0.7% oat oil polar fraction significantly delayed bread firming and starch retrogradation; the difference between oat lipids and shortening was more evident at the end of a four‐day storage period. Oat lipids had a stronger relative effect on bread from a weak flour (10% protein) than from a strong flour (14% protein). The effects of oat oil in the bread formulation could be related to the amphipathic character of polar lipids in oats that enables them to interact with starch, proteins, and other bread components.
Effect of Amylose Content on Expansion of Extruded Rice Pellet
Authors: Chen Chia‐Mao , Yeh An‐I
Published: June 2007

Rice pellets were prepared by single‐screw extrusion cooking with an in‐barrel water content of 50 wt%. Three different types of rice, indica glutinous, japonica, and indica, were used as raw materials. Reconstituted rice flour was made to study the effect of amylose content on pellet expansion. The glass transition (Tg) and expansion (Te) temperatures of extruded pellet were determined by differential scanning calorimetry (DSC) and noncontact infrared thermometer, respectively. The amylose content was not significantly affected by extrusion cooking. The reduction in intrinsic viscosity indicated that amylopectin experienced some degradation. The Tg and Te were not functions of amylose content, which affected the expansion ratio of the pellets. The Gordon‐Taylor equation was applied to estimate the Tg of the rice pellets.
Replacement of Shortening in Yellow Layer Cakes by Corn Dextrins
Authors: Kim Hye Young L. , Yeom Hyeon Won , Lim Hyesook S. , Lim Seung‐Taik
Published: June 2007

Shortening in a conventional yellow layer cake was replaced by maltodextrin (MD), amylodextrin (AD), octenyl succinylated amylodextrin (OSAD), or mixtures (MD+AD and MD+OSAD). The physical and sensory characteristics of the shortening‐free cakes were investigated. The specific gravity and viscosity of the cake batter, and the volume index of the baked cake were significantly reduced by MD, whereas the cake with added AD or OSAD showed a higher volume index than the control cake containing the shortening. An equivalent mixture of MD and AD, or MD and OSAD, however, produced cakes with a volume index and color defined as ΔE*(ab) that was similar to the control cake. Sensory evaluation revealed that the cakes containing AD or OSAD had significantly higher firmness than the control, but the cakes containing a mixture of MD and AD had firmness, springiness, and overall flavor scores similar to that of the control cake. According to instrumental texture profile analysis (TPA), MD addition, either alone or mixed with AD or OSAD, reduced firmness, whereas AD addition made the cake significantly firmer. When the shortening‐free cakes were stored for eight days at 4°C, TPA revealed greater changes in cake firmness and adhesiveness for MD alone. Cakes made from mixtures of dextrins (MD+AD and MD+OSAD) showed textural change with storage similar to that of the control cake, although the MD+AD cake remained softer than the control.
Measurement of Dynamic Dough Density and Effect of Surfactants and Flour Type on Aeration During Mixing and Gas Retention During Proofing
Authors: Campbell Grant M. , Herrero‐Sanchez Roberto , Payo‐Rodriguez Roman , Merchan Maria Luisa
Published: June 2007

A new method for measuring dough densities is presented, based on weighing small dough samples in air and immersed in xylene. The method can be used to evaluate the air content of low‐density doughs and to follow the changing density of a proofing dough sample. The method is applied to evaluate the effect of flour strength and surfactant addition on dough aeration and subsequent proofing. Doughs were mixed in a high‐speed mixer from two flours, a strong breadmaking flour and a weak flour. Surfactants sodium stearoyl lactylate (SSL) and diacetyl tartrate esters of monoglyceride (DATEM) were added at three levels, and the air content, proofing dynamics, and baked loaf quality were evaluated. The air content of dough was proportional to headspace pressure in the mixer, while the strong flour occluded less air than the weak flour. Surfactants greatly improved the volume of baked loaves but appeared to have no significant effect on air incorporation during mixing. The addition of surfactants appeared to increase the rate of growth of the dough piece during proofing, possibly due to increased bubble breakup during mixing or to increased rates of mass transfer of CO2 into bubbles during proofing.
Stability of Oat Avenanthramides
Authors: Dimberg Lena Häll , Sunnerheim Kerstin , Sundberg Birgitta , Walsh Kevin
Published: June 2007

The three main oat avenanthramides, N‐(4′‐hydroxy)‐(E)‐cinnamoyl‐5‐hydroxyanthranilic acid (Bp), N‐(4′‐hydroxy‐3′‐methoxy)‐(E)‐cinnamoyl‐5‐hydroxyanthranilic acid (Bf), and N‐(3′,4′‐dihydroxy)‐(E)‐cinnamoyl‐5‐hydroxyanthranilic acid (Bc), and their corresponding cinnamic acids, p‐coumaric (P), ferulic (F), and caffeic (C), were investigated for stability to pH, temperature, and UV‐light treatment. The retention of the avenanthramides after processing of oat‐based food products was also analyzed. The avenanthramide Bc and the cinnamic acid C were sensitive to alkali and neutral conditions, especially in combination with heat treatment, whereas the other compounds studied were more stable. The cinnamic acids but not the avenanthramides were isomerized when irradiated with UV‐light. The avenanthramides were restored after processing of oat‐based products.
Relationships of Selected Physical, Chemical, and Sensory Parameters in Oat Grain, Rolled Oats, and Cooked Oatmeal—A Three‐Year Study with Eight Cultivars
Authors: Lapveteläinen A. , Alho‐Lehto P. , Sinn L. , Laukkanen T. , Lindman T. , Kallio H. , Kaitaranta J. , Katajisto J.
Published: June 2007

Eight Scandinavian oat cultivars were studied as grains, groats before and after kiln drying, rolled oats, and oatmeal for 62 physical, chemical, and sensory parameters over three consecutive crop years. The objectives were to study cultivar and year differences, and the relationships between parameters to find out the cultivars most suitable for rolled oats production and to understand how grain parameters are reflected on groat, rolled oat, and oatmeal characteristics. The cultivars and crop years differed (P < 0.05) in most of the parameters. In addition, many groat, rolled oats, and oatmeal variables showed a significant year by crop interaction. Several grain variables were significantly interrelated but only two, moisture and amount of dark and damaged grains, had a strong correlation (r > 0.70) to rolled oat parameters, the former correlating negatively to crude fat and the latter positively with maximum viscosity value. However, some weaker (r < 0.70) negative associations were found such as those between kernel size value and β‐glucan content and water binding capacity of rolled oats. In general, the variables analyzed at different processing stages correlated strongly, indicating good retention of groat properties during processing. Various associations were found between the physicochemical parameters of rolled oats and sensory properties of oatmeal. In principal component analysis, factor 1 mostly represented rolled oat parameters such as crude fat, color values L and a, and oatmeal parameters such as toasted aromatics, coarseness, and size of swollen particles. Factor 2 represented properties that pertain to structure and water and rolled oats interactions. The cultivars were also grouped according to these properties. The results suggest that the rolled oat process deserves optimization on a cultivar basis, particularly when specific product properties such as good water binding capacity are required.
Detecting Corn Syrup in Barley Malt Extracts
Authors: Peterson David M. , Budde Allen D. , Henson Cynthia A. , Jones Berne L.
Published: June 2007

Methods for detecting corn syrup in barley (Hordeum vulgare L.) malt extract were evaluated. Twelve samples representative of commercially available 2‐rowed and 6‐rowed malting barleys were malted. Extracts prepared from the finely ground malts were analyzed for 13C/12C ratios, expressed as δ13C, and concentrations of protein and sugars. The 13C/12C ratios were sufficiently different to distinguish corn syrup from malt extract. By calculating the mean values for the barleys, it was determined that a δ13C > ‐24.3‰ indicated that the malt extract had been adulterated with corn syrup (99% confidence). Protein concentrations <4.5% (2‐rowed malt) or <5.0% (6‐rowed malt) of the extracts also indicated probable adulteration with corn syrup, which is devoid of protein. Because of differences in sugar concentrations between the malt extracts and corn syrup, carbohydrate analysis also indicated probable mixtures. These findings were confirmed by analysis of extracts from composite 2‐rowed and 6‐rowed barley malts that had been mixed with known quantities of corn syrup. The regressions for δ13C, protein concentration, and most sugar concentrations against percent dilution with corn syrup in the mixtures were significant.
Membrane Filtration of Corn Steep Water
Authors: Rane Kishore D. , Cheryan Munir
Published: June 2007

Membrane filtration is a cost‐effective alternative to heat pasteurization of corn steep water. Trials were done in an operating ethanol plant with commercial spiral‐wound modules. Flux increased with transmembrane pressure and became independent of pressure at >10 psi (69 kPa) with flux being higher at higher cross‐flow velocities. Average flux at 4× concentration factor over 24‐hr operating cycles was 34 L/m2/hr under optimum conditions. Capital cost of the membrane system is expected to be lower because it eliminates the heat pasteurizer and centrifuge and reduces cooling requirements. Operating cost of the microfilter are about one‐third of a heat pasteurization system and provides the opportunity to recover insoluble protein and starch for use in corn gluten feed. Microfiltered steep water could improve ethanol fermentation efficiency and reduce fouling of heat exchangers in the fermenters, beer still, and steep evaporators.
Use of Sonication to Probe Wheat Gluten Structure
Authors: Singh H. , MacRitchie F.
Published: June 2007

Variation in power and time of sonication of gluten and glutenin suspensions was used to gain information about the mechanism of molecular breakdown. At low power, an increase in sulfhydryl (SH) content of solubilized gluten could be ascribed to additional glutenin brought into the solution. Higher power sonication of gluten suspensions, at constant protein concentration and with increasing times, progressively shifted the molecular weight distribution (measured by size exclusion HPLC) to lower molecular weights. It was accompanied by a parallel decrease in SH content. This suggested that the freed cysteine residues formed by scission of disulfide (SS) bonds, caused by sonication, reacted to form new intramolecular SS bonds with free cysteines on the same molecular fragments. Circular dichroism measurements appeared to support this conclusion. High‐power ultrasound produced SE‐HPLC profiles with diffuse peaks corresponding to HMW‐GS and LMW‐GS. SDS‐PAGE patterns of protein fractions obtained in different elution ranges of SEHPLC confirmed that individual subunits had been produced by sonication. A fraction of the polymeric protein eluting at the void volume of SE‐HPLC appeared to be resistant to breakdown by sonication.
Farinograph Responses for Wheat Flour Dough Fortified with Wheat Gluten Produced by Cold‐Ethanol or Water Displacement of Starch
Authors: Robertson G. H. , Cao T. K.
Published: June 2007

The objective of this research was to identify and define mixing characteristics of gluten‐fortified flours attributable to differences in the method for producing the gluten. In these studies, a wheat gluten concentrate (W‐gluten) was produced using a conventional process model. This model applied physical water displacement of starch (dispersion and screening steps), freeze‐drying, and milling. W‐gluten was the reference or “vital” gluten in this report. An experimental W‐concentrate was produced using a new process model. The new model applied coldethanol (CE) displacement of starch (dispersion and screening steps), freeze‐drying, and milling. Freeze‐drying was used to eliminate thermal denaturation and thereby focus on functional changes due only to the separation method. The dry gluten concentrates were blended with a weak, low‐protein (9.2%), soft wheat flour and developed with water in a microfarinograph. We found that both water and cold‐ethanol processed gluten successfully increased the stability (St) and improved mixing tolerance index (MTI) to create in the blended flour the appearance of a breadbaking flour. Notably, in the tested range of 9–15% protein, the St for CE‐gluten was always higher then the St for W‐gluten. Furthermore, the marginal increase in St (slope of the linear St vs. protein concentration) for the CE‐gluten was ≈57% greater than that for the W‐gluten. The slope of the MTI vs. protein data was lower for the CE‐gluten by 24%. Flour fortified with CE‐gluten exhibited higher water absorption (up to 1.8% units at 13.5% P) than flour fortified with W‐gluten.
Factors Influencing the Characterization of Gluten Proteins by Size‐Exclusion Chromatography and Multiangle Laser Light Scattering (SEC‐MALLS)
Authors: Bean S. R. , Lookhart G. L.
Published: June 2007

The use of multiangle laser light scattering (MALLS) in conjunction with size exclusion chromatography (SEC) was investigated for characterizing wheat proteins. Four solvent systems including 50% acetonitrile and 0.1% trifluoroacetic acid, 50 mM sodium phosphate (NaPhos) pH 2.5, 500 mM acetic acid, and 50 mM NaPhos pH 7.0 + 1% SDS were evaluated for protein extraction as well as for use as SEC mobile phases for MALLS analysis. The dn/dc values for wheat proteins were measured in each solvent. Except for the SDS‐based mobile phase, gluten proteins showed dn/dc values of 0.16–0.20 that were similar to values reported for other proteins. When analyzed in the SDS solvent, gluten proteins showed dn/dc values of 0.32, similar to that found for other SDS‐protein complexes. While all solvents showed similar resolution when used as mobile phases in SEC analysis, the SDS solvent extracted the most protein (≈82%) in the unreduced form. This solvent system also displayed no concentrationdependent or electrostatic effects during MALLS analysis. SDS‐soluble and insoluble protein complexes were characterized by MALLS. Mw distributions of 8.1 × 107 Da were found for the SDS‐insoluble protein complexes. The effect of the column void volume was also examined as was data analysis parameters such as fitting method and peak placement.
Correlation Between Starch Retrogradation and Water Mobility as Determined by Differential Scanning Calorimetry (DSC) and Nuclear Magnetic Resonance (NMR)
Authors: Lin Yu‐shiun , Yeh An‐I , Lii Cheng‐yi
Published: June 2007

Starches from nine varieties of rice, including four indica, three japonica, and two waxy cultivars, were used for the investigation of the correlation between retrogradation and water mobility. Retrogradation and water mobility were analyzed by differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) and expressed as enthalpy change (ΔH) and differential relaxation rate (ΔR2) for water‐17O. Water contents were measured by DSC and Karl‐Fischer methods. The results indicated that three different profiles, based on amylose content, were observed for the ΔH changes of rice starch cooks during storage. They fit well to the nonlinear regression equations of exponential rise to maximum and exponential growth models. The water content, as measured with DSC, decreased during storage but increased as measured with the Karl‐Fischer method. This discrepancy might be attributed to the different characteristics of water measured by the two methods. The ΔR2 of rice starch cooks showed an increasing trend during storage but was more complicated than the ΔH trend. The nonlinear regression models were also applied to fit the changes of ΔR2 for indica varieties in the initial six days and for waxy varieties up to 24 days. This resembled the ΔH changes.