bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the Mechanism of Cross‐Linking Agents (POCl3, STMP, and EPI) Through Swelling Behavior and Pasting Properties of Cross‐Linked Waxy Maize Starches
Authors: Hirsch Julie B. , Kokini Jozef L.
Published: June 2007

The effects of cross‐linking waxy maize starch with phosphorous oxychloride (POCl3), sodium trimetaphosphate (STMP), or epichlorohydrin (EPI) on degree of swell and pasting properties were studied. As expected, increased concentration of cross‐linking agent resulted in decreased granule swelling potential, Q (mL/g). The slower acting reagents, STMP (4‐hr reaction time) and EPI (17‐hr reaction time), showed a similar relation between Q value and molar concentration of agent, which was different from the faster‐acting POCl3 (30‐min reaction time). Brabender viscoamylograph results show decreased peak viscosity with increasing amounts of cross‐link agent due to increased inhibition to swelling. Brabender viscosities (BU) continued to increase after the time interval in which an uncross‐linked sample would dissolve, which may be a sign of flocculation. The magnitude of BU for all of the treatments after 41 min, plotted versus calculated molar concentration of cross‐linking agent, showed a similar trend for all three reagents, indicating that type of reagent plays little effect on the overall pasting behavior of cross‐linked waxy maize. However, when BU was plotted versus Q, starches treated with POCl3 again separated themselves with much higher viscosities than the collectively grouped EPI‐ and STMP‐treated starches. The combination of the reduced swell and higher viscosity indicates that POCl3‐treated granules have a more rigid external surface area, with hard crust formed on the outer layers of the granule. This information shows that the mechanism of action of the individual reagents plays a major role in the physicochemical behavior of the starches.
Granular Cold Water Gelling Starch Prepared from Chickpea Starch Using Liquid Ammonia and Ethanol
Authors: Jackowski R. , Czuchajowska Z. , Baik B.‐K.
Published: June 2007

Granular cold water gelling (GCWG) starch was obtained by treatment of native chickpea starch with liquid ammonia at low temperature and atmospheric pressure. A free‐flowing powder of the gelatinized starch granules was produced by adding ethanol to the mixture of starch and liquid ammonia. Four ratios of liquid ammonia to starch (A/S) (2:1, 4:1, 6:1 and 8:1) and four ratios of starch ethanol (S/E) (1:1, 1:2, 1:3 and 1:4) were tested for production of GCWG starch. Homogenous mixtures of liquid ammonia and starch granules appeared when the A/S ratio was >4:1. Treating starch with a 4:1:3 ammonia‐starch‐ethanol (A/S/E) ratio on a w/w/v basis resulted in a free‐flowing powder of gelatinized starch, that formed a gel on addition of water at 23°C. Differential scanning calorimetry (DSC) thermograms of the GCWG starch, regardless of A/S/E ratio, displayed enthalpy values of 2.2–3.1 J/g compared with 15.5 J/g for native starch, indicating disappearance of crystallinity due to modification.
Effect of Glass Transition and Cross‐Linking on Rheological Properties of Gluten: Development of a Preliminary State Diagram
Authors: Toufeili Imad , Lambert Ian A. , Kokini Jozef L.
Published: June 2007

The glass transition temperature of gluten at different moisture levels was determined by differential scanning calorimetry and mechanical spectrometry. The dynamic moduli (G′ and G″) of gluten with 10–40% moisture were measured as a function of temperature by pressure rheometry. At 10% moisture, gluten exhibited entangled polymer flow at 92–140°C and networking reactions at higher temperatures. At higher moisture levels, gluten experienced structured flow before networking cross‐linking reactions. The onset temperature of the reaction zone was 120°C in 20% moisture gluten and 93°C at moisture levels of 30–40%. Softening of the vitrified network occurred at 184, 181, and 170°C in 20, 30, and 40% moisture gluten, respectively. A preliminary state diagram of gluten as a function of moisture and temperature was developed.
Amylopectin Nature and Amylose‐to‐Amylopectin Ratio as Influences on the Behavior of Gels of Dispersed Starch
Authors: Klucinec Jeffrey D. , Thompson Donald B.
Published: June 2007

The importance of the nature of the amylopectin and the amylose‐to‐amylopectin ratio in the gelation of high‐amylose maize starch was examined by preparing gels of model systems using amylose (AM) from a high‐amylose maize starch mixed with an amylopectin (AP): either wx starch, acid‐hydrolyzed wx starch (AH‐wx), ae wx starch, or wx β‐limit dextrin. Mixtures of 7.5% starch in 20% dimethyl sulfoxide (DMSO) were examined by differential scanning calorimetry and dynamic oscillatory rheometry. Mixtures of 1.88 or 3.75% AM with the remainder either wx or AH‐wx developed a measurable elastic modulus (G′) within one day, more quickly than for the corresponding AP without AM. Gels of AM with either wx or AH‐wx starch developed a higher retrogradation enthalpy (ΔH) than corresponding AP without AM when the ΔH values were normalized to the amylopectin content. The G′ and ΔH of all gels containing ae wx did not change after one day. During heating of the gels to 80°C, most of the G′ at 25°C was lost, indicating that the initial gel structure was not due to a thermally stable AM network. Gelation is proposed to be due to physical junction zones (PJZ) between AM molecules (AM‐AM), between AM and amylopectin molecules (AM‐AP), and between amylopectin molecules (AP‐AP). For wx, AH‐wx, or ae wx starch, the higher G′ and ΔH of the gels with 3.75% AM compared with the gels with 1.88% AM suggests that AM‐AP PJZ are more important in gel formation when AM makes up half the starch. Gels from the mixture of 3.75% AM and 3.75% ae wx starch behaved most similarly to gels of 7.5% high‐amylose maize starch. The development of a starch gel is affected by both the nature of the amylopectin as well as the amylose‐to‐amylopectin ratio of the gel.
Effect of Physical State of Nonpolar Lipids on Rheology and Microstructure of Gluten‐Starch and Wheat Flour Doughs
Authors: Watanabe Akihiro , Larsson Helena , Eliasson Ann‐Charlotte
Published: June 2007

To clarify the effects of solid fat and liquid oil on dough in more detail in a simpler system, gluten‐starch doughs with different gluten contents were investigated. The results from rheological measurements indicate that dough with a higher starch content has less resistance to strain and dough with a lower starch content has a rubber‐like structure. The effects of the physical state of nonpolar lipids such as fat and oil on gluten‐starch doughs and wheat flour doughs were investigated using rheological measurements and scanning electron microscopy. Fat‐containing dough had more gas cells and a very smooth gluten gel surface with few holes, which may provide higher tolerance to strain. Moreover, the fat seemed to uniformly distribute the gluten gel between the starch granules in the dough, which reduced the friction between starch granules and led to a lower storage modulus. A mechanism governing the effect of fats on loaf volume is proposed based on the phenomena observed in the fat‐containing dough.
Structural and Functional Characteristics of Selected Soft Wheat Starches
Authors: Franco Célia M. L. , Wong Kit‐Sum , Yoo Sang‐ho , Jane Jay‐lin
Published: June 2007

Starches from eight soft wheat samples (two parent lines and six offspring) were isolated; relationships between their structures and properties were examined. Branch chain‐length distributions of amylopectins were determined by using high‐performance anion exchange chromatography equipped with an amyloglucosidase reactor and a pulsed amperometric detector (HPAEC‐ENZ‐PAD). Results showed that the average chain length of the eight samples varied at DP 25.6–26.9. Starch samples of lines 02, 60, 63, 95, and 114 consisted of amylopectins with more long chains (DP ≥ 37) and longer average chain length (DP 26.2–26.9) than that of other samples. These starch samples of longer branch chain length displayed higher gelatinization temperatures (55.3–56.5°C) than that of other samples (54.4–54.9°C) and higher peak viscosity (110–131 RVU) and lower pasting temperature (86.3–87.6°C) than others (83–100 RVU and 88.2–88.9°C, respectively). The Mw of amylopectins, determined by using high‐performance size exclusion chromatography equipped with multiangle laser‐light scattering and refractive index detectors (HPSEC‐MALLS‐RI), were similar for all samples (6.17 × 108 to 6.97 × 108). There were no significant differences in amylose and phosphorus contents between samples. These results indicated that physical properties of wheat starch were affected by the branch‐chain length of amylopectin.
Corn Dry‐Milled Grit and Flour Fractions Exhibit Differences in Amylopectin Fine Structure and Gel Texture
Authors: Lin Y.‐P. , Aboubacar A. , Zehr B. E. , Hamaker B. R.
Published: June 2007

Corn starch amylopectin (AP) fine structure and gel textural properties of dry‐milled grit and flour fractions were investigated in 10 corn cultivars. Amylopectin was isolated by fractionating the starch derived from these two milled fractions using size‐exclusion chromatography (SEC). Fine structure was characterized by SEC after thorough debranching with pullulanase. SEC revealed three major fractions of debranched AP from the grit and flour portion. Amylopectin in the grit portion had a significantly higher proportion of long chains (DPn 70–75) and a postulated lower extent of chain branching than its flour counterpart. Texture profile analysis showed that flour gels from the grit fraction had significantly higher values for hardness, gumminess, and springiness compared with gels from the floury fraction. Trends were similar for starch gels of the two dry‐milled fractions, though only springiness was significantly different. The finding that differences in AP fine structure in dry‐milled fractions relate to gel textural differences suggests that dry millers may be able to produce flours of different functionalities that would be suited for different end uses. Additionally, mixing the dry‐milled flour fraction with a grit‐derived flour would result in different product properties.
Properties and Structures of Flours and Starches from Whole, Broken, and Yellowed Rice Kernels in a Model Study
Authors: Wang Ya‐Jane , Wang Linfeng , Shephard Donya , Wang Fudong , Patindol James
Published: June 2007

The objective of this study was to compare the structure and properties of flours and starches from whole, broken, and yellowed rice kernels that were broken or discolored in the laboratory. Physicochemical properties including pasting, gelling, thermal properties, and X‐ray diffraction patterns were determined. Structure was elucidated using high‐performance size‐exclusion chromatography (HPSEC) and high‐performance anion‐exchange chromatography with pulsed amperometric detection (HPAEC‐PAD). The yellowed rice kernels contained a slightly higher protein content and produced a significantly lower starch yield than did the whole or broken rice kernels. Flour from the yellowed rice kernels had a significantly higher pasting temperature, higher Brabender viscosities, increased damaged starch content, reduced amylose content, and increased gelatinization temperature and enthalpy compared with flours from the whole or the broken rice kernels. However, all starches showed similar pasting, gelling, thermal properties, and X‐ray diffraction patterns, and no structural differences could be detected among different starches by HPSEC and HPAEC‐PAD. α‐Amylase may be responsible for the decreased amylopectin fraction, decreased apparent amylose content, and increased amounts of low molecular weight saccharides in the yellowed rice flour. The increased amount of reducing sugars from starch hydrolysis promoted the interaction between starch and protein. The alkaline‐soluble fraction during starch isolation is presumed to contribute to the difference in pasting, gelling, and thermal properties among whole, broken, and yellowed rice flours.
Flavor Retention and Physical Properties of Rice Cakes Prepared from Coated Rice Grain
Authors: Klamczynski A. P. , Glenn G. M. , Orts W. J.
Published: June 2007

Flavored rice cakes are produced commercially by spraying a flavor coating on the cake surface. This study describes a method of making a flavored coating that is applied to individual rice grains before puffing and results in a more uniform flavor distribution. Rice was coated at 5% or 10% levels with coating materials made of jet‐cooked (JC) starch or starch cooked in a water bath (WB), corn starch powder, salt, and a flavor compound. The viscosity of coating materials made with WB starch was twice that of coatings made of JC starch. Rice coated at 10% level had decreased specific density of rice cakes. Rice cakes made from coated grain were similar in appearance to cakes made from uncoated rice but had higher flexural strength. Retention of flavor volatiles after puffing the coated grain was 82.8–56.8% for apple, 72.5–40.3% for anise, and 52.5–24.8% for onion flavor. The flavor volatiles measured in the rice cakes decreased during a three‐month storage period to 49.3% for apple, 25.8% for anise, and 10.1% for onion flavor. Slightly higher retention of flavor volatiles was observed in cakes made with WB starch than in cakes made with JC starch. The difference in retention of flavor volatiles between starch slurry or starch‐oil emulsion treatments was small.
Dough and Baking Properties of High‐Amylose and Waxy Wheat Flours
Authors: Morita Naofumi , Maeda Tomoko , Miyazaki Megumi , Yamamori Makoto , Miura Hideho , Ohtsuka Ichiro
Published: June 2007

The dough properties and baking qualities of a novel high‐amylose wheat flour (HAWF) and a waxy wheat flour (WWF) (both Triticum aestivum L.) were investigated by comparing them with common wheat flours. HAWF and WWF had more dietary fiber than Chinese Spring flour (CSF), a nonwaxy wheat flour. Also, HAWF contained larger amounts of lipids and proteins than WWF and CSF. There were significant differences in the amylose and amylopectin contents among all samples tested. Farinograph data showed water absorptions of HAWF and WWF were significantly higher than that of CSF, and both flours showed poorer flour qualities than CSF. The dough of WWF was weaker and less stable than that of CSF, whereas HAWF produced a harder and more viscous dough than CSF. Differential scanning calorimetry data showed that starch in HAWF dough gelatinized at a lower temperature in the baking process than the starches in doughs of WWF and CSF. The starch in a WWF suspension had a larger enthalpy of gelatinization than those in HAWF and CSF suspensions. Amylograph data showed that the WWF starch gelatinized faster and had a higher viscosity than that in CSF. The loaves made from WWF and CSF were significantly larger than the loaves made from HAWF. However, the appearance of bread baked with WWF and HAWF was inferior to the appearance of bread baked with CSF. Bread made with WWF became softer than the bread made with CSF after storage, and reheating was more effective in refreshing WWF bread than CSF bread. Moreover, clear differences in dough and bread samples were revealed by scanning electron microscopy. These differences might have some effect on dough and baking qualities.
Physical and Cooking Quality of Spaghetti Made from Whole Wheat Durum
Authors: Manthey Frank A. , Schorno Anton L.
Published: June 2007

The effects of cultivar on dough properties of ground whole wheat durum, and the effects of cultivar and drying temperature on the physical and cooking quality of spaghetti made from semolina and whole wheat were evaluated. Rankings of cultivars based on dough properties were similar for whole wheat and semolina. Dough made from whole wheat was weak and had poor stability. Whole wheat spaghetti had a rough reddish brown surface compared with the very smooth, translucent yellow color of spaghetti made from semolina. The reddish brown color of whole wheat spaghetti was enhanced by high‐temperature drying (70°C). Mechanical strength and cooking quality of spaghetti made from ground whole wheat or semolina varied with cultivar and with drying temperature. Compared with spaghetti made from semolina, whole wheat spaghetti had lower mechanical strength and cooked firmness and had greater cooking loss. Mechanical strength of whole wheat spaghetti was lower when dried at high temperature (70°C) than at low temperature (40°C). Conversely, the mechanical strength of spaghetti made from semolina was greater when dried at high temperature than at low temperature. Whole wheat and traditional spaghetti dried at high temperature had lower cooking losses than spaghetti dried at low temperature. When overcooked 6 min, firmness of spaghetti made from semolina or whole wheat was greater when dried at high temperature than at low temperature.
Sources of Variation in Oat Kernel Size
Authors: Doehlert Douglas C. , McMullen Michael S. , Riveland Neil R.
Published: June 2007

Oat kernel size uniformity is important to the oat milling industry because of the size fractionations that occur in the milling process. We measured frequency of single, double, and triple kernel spikelets and kernel mass of primary, secondary, and tertiary kernels from each spikelet type (for a total of six kernel types) to determine relative influence of kernel type, panicle position, genotype, and environment on oat kernel size for 10 oat cultivars grown at four locations. Kernel type was the most important factor affecting kernel size. Primary kernels from triple kernel spikelets were larger than primary kernels from double kernel spikelets. Tertiary kernels were the smallest. Environments that produced larger kernels also produced higher frequencies of triple kernel spikelets. Some genotypes produced no triple kernel spikelets in any environment, whereas others produced varying proportions, depending on the environment. Kernels closer to the top of the panicle were larger than those near the base. The presence of tertiary kernels was neither associated with lower groat percentages nor with increased proportions of undersized kernels. Most undersized kernels were kernel types other than tertiary.
Pasting Process in Rice Flour Using Rapid Visco Analyser Curves and First Derivatives
Authors: Meadows Frederick
Published: June 2007

The objective of these studies was to gain a better understanding of the pasting process in rice. We chose six different medium grain rice flour samples with amylose contents of 0.41–24.9% and protein contents of 4.89–10.65%. By using the first derivative of Rapid Visco Analyser (RVA) curves, changes in the pasting rates could be obtained. We found that samples containing low amylose contents (CM101 [CA] 0.41% amylose and 7.04% protein) exhibited a single smooth transition during pasting. Pastes from all other samples, M201 (TX), Nato (LA), Koshihikari (CA), Mercury (LA), and Nanking Sel (LA) with higher amylose contents (10.65–24.9%) underwent multiple phase transitions and rate changes before the peak viscosity. Disruption of disulfide linkages using dithiothreitol (DTT) led to a decrease in the rate of the single pasting step observed for CM101 (CA). Rice containing larger concentrations of amylose showed an increase in the first, but a decrease in subsequent steps. Our data suggests that amylopectin and protein are mutually important in the initialization of pasting in rice. At later stages of pasting, amylose and its complexes seem to become important.
Determination of Rapid Visco Analyser Parameters in Rice by Near‐Infrared Spectroscopy
Authors: Meadows Frederick , Barton Franklin E.
Published: June 2007

The objective of these studies was to find alternative Rapid Visco Analyser (RVA) viscoelastic parameters that are predictable by near‐infrared spectroscopy (NIRS). Currently, RVA instruments are widely used in assessing cooking and processing characteristics in rice. The ability to predict RVA parameters by NIRS would be useful in rapidly determining rice pasting qualities, but NIRS does not correlate with the traditional parameters (peak viscosity, final viscosity, breakdown, consistency, and setback). Alternative RVA parameters were sought by collecting RVA and NIRS data for a total of 86 short, medium, and long grain rice cultivars. The amylose contents were 0.41–24.90% (w/w) and protein concentrations were 8.47–11.35% (w/w). Partial least squares (PLS) regression models generated for the entire NIR spectrum against the RVA curve showed viscosity at 212–228 sec (80°C ± 1) varied linearly with NIR spectra (1,100 to ‐2,500 nm). Regression coefficient values were R = 0.961 for 212 sec and R = 0.903 for 228 sec. The PLS correlation coefficient for the prediction of amylose at 212–228 sec decreases along with the NIRS correlation to the same time frame. An opposite trend was observed for the correlation with protein at 212–228 sec. This comparison suggests the importance of amylose and protein in water absorption during this time frame.
Physicochemical Properties of Corn Starch Selectively Oxidized with 2,2,6,6‐Tetramethyl‐1‐Piperidinyl Oxoammonium Ion
Authors: Suh Dong Soon , Chang Pahn Shick , Kim Kwang‐Ok
Published: June 2007

This study was conducted to examine the characteristics of oxidation reaction on the primary alcohol groups in corn starch, when 2,2,6,6‐tetramethyl‐1‐piperidinyl oxoammonium ion (TEMPO) was used, and to determine the optimum conditions for the preparation of oxidized corn starch (OCS). Applicability of the OCS in the food system was also investigated. The effects of TEMPO, sodium bromide (NaBr), and temperature on oxidation reaction time, yield, and selectivity for primary alcohol groups were examined by response surface methodology. As the temperature and the levels of TEMPO and NaBr increased, reaction time and selectivity decreased. Yield decreased with increased NaBr and selectivity decreased with the increased temperature and NaBr. Selectivity increased with higher TEMPO levels up to a certain point and then decreased. Optimum levels of TEMPO, NaBr, and temperature for the preparation of OCS were determined as 0.6 mM/100 mM of anhydroglucose unit (AGU), 45 mM/100 mM AGU, and 7°C, respectively. Water binding capacity, emulsion stability, and viscosity of starch increased significantly by oxidation. Corn starch containing OCS had decreased initial pasting temperature, setback, and gelatinization and retro‐gradation enthalpy (ΔH). Corn starch gel containing OCS showed delayed staling during storage.
Modification of Starch by Dry Heating with Ionic Gums
Authors: Lim S.‐T. , Han J.‐A. , Lim H. S. , BeMiller J. N.
Published: June 2007

Waxy maize (native and hydroxypropylated [HP]) and potato starches were impregnated with ionic gums (sodium alginate, CMC, and xanthan, 1% based on starch solids) and heat‐treated in a dry state for 0, 2, or 4 hr at 130°C. Effects of the dry heating on paste viscosity (RVA) and clarity (light transmittance) were examined. Heat treatment with sodium alginate and CMC raised the paste viscosities of native and HP waxy maize starches, but decreased that of potato starch. Xanthan provided the most substantial changes in paste viscosity among the tested gums. It appeared to heavily restrict granule swelling of the waxy maize starches, but it increased swelling of potato starch granules. Dry heating raised the paste viscosity of all the starch‐gum mixtures tested, except the potato starchalginate mixture. The final viscosity at 50°C of a 7% paste was raised in all other starches by ≈500–1,000 cP by this treatment. The paste of waxy maize starch‐gum products became opaque and shorter textured by the heat treatment, regardless of the gum type, whereas potato starch‐gum products did not show any obvious change in paste clarity. Ionic gums could behave as cross‐linking agents as well as form graft copolymers through heatinduced ester formation. This simple heating process with ionic gums could be used as a modification method for starch.
Investigation of the Effect of Hot Air Drying of Wheat Gluten on Its Viscoelasticity and Baking Performance by a Systems Analytical Model
Authors: Meuser F. , Kutschbach A. , Kieffer R. , Wieser H. , Schieberle P.
Published: June 2007

Drying experiments were conducted with wet gluten according to a newly developed systems analytical model to describe the effect of drying parameters on the viscoelasticity of wheat gluten and its baking performance. Gluten was extracted from two wheat flours differing in protein, wet gluten content, and viscoelastic properties as determined by extensigrams and farinograms. The glutens extracted from doughs were mixed with wheat starch (A grade) to establish a model system in which the most important drying parameters (hot air temperature, dry matter content of the feed, add‐back cycle) could be varied on different levels. The gluten‐starch mixtures were dried by a flash dryer. The experiments were designed according to a factorial experimental plan in which the drying parameters were correlated with the shear time of the glutens extracted from the dried products. Aliquots of the extracted glutens were freeze‐dried and used for dough‐forming experiments (microfarinograms) and microbaking tests. The dough development time and the baking volume were each statistically related to the shear time. Viscoelasticity of the glutens originating from the two flours decreased with increasing hot air temperature and number of drying steps. Lowering the dry matter content of the feed resulted in a similar reduction. The declining viscoelasticity was reflected in increased dough development time and decreased baking volume. Thus, the functional relationships postulated by the systems analytical model developed for the description of the gluten drying process have been verified on the basis of the statistically evaluated results of the drying experiments. From this follows that the viscoelasticity of gluten can be controlled by varying the parameters of hot air drying processes.
Effect of Single Strain and Traditional Mixed Strain Starter Cultures on Rheological Properties of Wheat Dough and on Bread Quality
Authors: Clarke C. I. , Schober T. J. , Arendt E. K.
Published: June 2007

Investigations were made to test the effect of two different sourdough starter culture types on wheat dough and bread quality. Two single‐strain starter cultures consisting of well‐defined strains of lactic acid bacteria (Lactobacillus plantarum, L. brevis) and a traditional mixed‐strain sourdough culture (containing L. crispatus, L. pontis, and Saccharomyces cerevisiae) were evaluated for their effects on the rheological characteristics of wheat dough using both fundamental rheological and standard baking tests. Two other doughs were also evaluated, one which was chemically acidified to a comparable pH value by the addition of lactic acid, and a control which was not acidified. Dynamic oscillation tests were performed using a controlled stress rheometer. The phase angle and the absolute value of the complex dynamic modulus were measured for all doughs at frequencies of 0.1–10 Hz. The addition of sourdough prepared using single‐strain or mixed‐strain cultures significantly increased the phase angle and reduced the complex modulus of the doughs at all frequencies (P < 0.05). Significant differences were found between the dough which was chemically acidified and those doughs which were biologically acidified. The addition of sourdough effected an increase in loaf specific volume relative to both the chemically acidified and the nonacidified doughs.
Effects of Maturity on Grain Quality and Wet‐Milling Properties of Two Selected Corn Hybrids
Authors: Jennings S. D. , Myers D. J. , Johnson L. A. , Pollak L. M.
Published: June 2007

The effects of maturity on grain quality and wet‐milling properties were investigated for two hybrids of corn. Significant differences for hybrid and maturity were observed for all grain quality parameters. Test weight, absolute density, and thousand‐grain weight all increased as the corn matured. Kernel hardness increased and breakage susceptibility varied with increased maturity. Water uptake parameters decreased with maturity of the grain. The starch yield results from wet milling showed that the starch yield increased significantly within each cultivar in the early stages of grain maturity, but there were no significant differences between hybrids. Mathematical models using selected grain quality parameters accurately predicted trends in starch yield for the immature and mature corn samples in this study.
Protein Allelic Composition, Dough Rheology, and Baking Characteristics of Flour Mill Streams from Wheat Cultivars with Known and Varied Baking Qualities
Authors: Menkovska M. , Knezevic D. , Ivanoski M.
Published: June 2007

Flour mill streams obtained by milling grain of 10 bread wheat cultivars grown in the Skopje region of Macedonia were analyzed for rheological and breadmaking quality characteristics and for composition of gliadins and HMW‐GS. The objective of this study was to examine the relationships between the composition of gluten proteins and breadmaking quality, as well as to determine the importance of gluten proteins for technological quality of flour mill streams. The grain was milled in an experimental mill according to a standardized milling procedure, with three break and three reduction passages. The addition of two vibratory finishers in the milling scheme enabled better separation of bran. A small‐scale baking method for evaluation of the breadmaking properties was developed, and electrophoretic methods including acid‐PAGE and SDS‐PAGE were used to determine the composition of the gluten proteins. There were significant differences in the degree of dough softening of individual and total flour fractions of the flour mill streams for cultivars with different alleles from six loci, for farinograph water absorption from seven loci, and for bread loaf volume and crumb quality score from six loci. The Glu‐1 quality scores for the wheat cultivars investigated were 3–9 and proved to be a useful indicator of breadmaking quality. The novel feature of the investigation related to the breadmaking potential of the flour mill streams compared with straight‐run flours.
Influence of UV Exposure on Phenolic Acid Content, Mechanical Properties of Bran, and Milling Behavior of Durum Wheat (Triticum Durum Desf.)
Authors: Peyron Stéphane , Abecassis Joël , Autran Jean‐Claude , Rouau Xavier
Published: June 2007

Durum wheat bran was exposed to UV radiation up to 48 hr and the changes in ferulic acid (FA) content in the peripheral part s of grain were measured. The treatment resulted in a 25% decrease in FA monomer and a 44% decrease in dehydrodiferulic acid (DHD) ester‐linked to the cell‐wall arabinoxylans. This reduction was partly explained by a significant increase of FA (30%) and DHD (36%) engaged in hot alkali‐labile linkages. The results suggest that UV irradiation induced the formation of new cross‐links between feruloylated arabinoxylan and lignin in the pericarp. The effects of UV treatment on bran mechanical properties and wheat milling behavior were investigated. UV irradiation for 15 hr increased the stress to rupture by 30% and decreased the extensibility of bran tissues by 54%. This stiffening was associated with an increase in bran friability during grinding. Although this effect was due in part to the hydrothermal history of the grain, chemical modification induced by UV significantly influenced the size reduction of bran particles, which can be explained by the modification of the mechanical properties of bran. Relationships between the organization of cell‐wall polymers, the mechanical properties of tissues, and the behavior of wheat grain during milling were investigated.
Effect of Holding Temperature on the Structures of Mung Bean Starch Gels and Noodles
Authors: Ohwada N. , Ishibashi K. , Hironaka K.
Published: June 2007

The effect of storage temperatures (‐10, +1, and +10°C) on the structural organization of mung bean starch gels and noodles was studied by acid hydrolysis, X‐ray diffractometry, and gel‐permeation chromatography. The gels showed higher susceptibility to acid compared with the noodles as shown by the rate constants of the first stage of hydrolysis (k = 5.37–12.17 × 10‐2/day and k = 4.19–4.61 × 10‐2/day for gels and noodles, respectively). Acid hydrolysis showed no difference in the amount of resistant residues of both gels (42–46%) and noodles (44–45%), except for gels (38%) stored at ‐10°C. The acid‐resistant residues of both the gels and noodles had a B‐type X‐ray diffraction pattern (major reflections at 2θ = 19, 24, and 25°). The acid‐resistant residues of the unstored sample and those stored at ‐10°C for both gels and noodles contained chains with DP 46–54 and after debranching yielded two peaks with DP 29–39 and DP 15–19. The acid‐resistant residues of gels and noodles stored at +1 and +10°C contained chains with DP 35–37 and after debranching showed two chain populations with DP 31–33 and DP 14–19. These results indicate the greater participation of amylopectin in the retrogradation process occurring during storage at +1 and +10°C.
Mixograph Responses of Gluten and Gluten‐Fortified Flour for Gluten Produced by Cold‐Ethanol or Water Displacement of Starch from Wheat Flour
Authors: Robertson G. H. , Cao T. K.
Published: June 2007

The total protein of gluten obtained by the cold‐ethanol displacement of starch from developed wheat flour dough matches that made by water displacement, but functional properties revealed by mixing are altered. This report characterizes mixing properties in a 10‐g mixograph for cold‐ethanol‐processed wheat gluten concentrates (CE‐gluten) and those for the water‐process concentrates (W‐gluten). Gluten concentrates were produced at a laboratory scale using batter‐like technology: development with water as a batter, dispersion with the displacement fluid, and screening. The displacing fluid was water for W‐gluten and cold ethanol (≥70% vol, ‐12°C) for CE‐gluten. Both gluten types were freeze‐dried at ‐10°C and then milled. Mixograms were obtained for 1) straight gluten concentrates hydrated to absorptions of 123–234%, or 2) gluten blended with a low protein (9.2% protein) soft wheat flour to obtain up to 16.2% total protein. The mixograms for gluten or gluten‐fortified flour were qualitatively and quantitatively distinguishable. We found differences in the mixogram parameters that would lead to the conclusion of greater stability and strength for CE‐gluten than for W‐Gluten. Differences between the mixograms for these gluten types could be markedly exaggerated by increasing the amount of water to the 167–234% range. Mixograms for evaluation of gluten have not been previously reported in this hydration range. Mixograms for fortification suggest that less CE‐gluten than W‐gluten would be required for the same effect.
Understanding and Modeling the Processing‐Mechanical Property Relationship of Bread Crumb Assessed by Indentation
Authors: Liu Zhiqiang , Scanlon Martin G.
Published: June 2007

Measuring fundamental mechanical parameters such as Young's modulus and critical stress is a straightforward and valid approach to evaluating the physical texture of breadcrumb. The objectives of this study were to evaluate whether such fundamental mechanical properties could be measured by indentation techniques such as the AACC crumb firmness method, and then to alter breadmaking conditions so as to model the relationship between these indentation mechanical properties as a function of crumb moisture content and crumb density. Bread was baked according to a short dough process using Canadian western red spring (CWRS) wheat flour. Factors considered in the design of experiments were proofing time, water absorption, crosshead speed, and indenter diameter. Young's modulus and critical stress, measured with 12‐ and 20‐mm cylindrical indenters, were well covalidated with those obtained from a standard compression test. With increases in proofing time and water absorption, a more porous and compliant bread texture led to decreasing Young's modulus and critical stress. Our results revealed a good mapping of mechanical properties to crumb moisture content and density that were correlated to breadmaking conditions, thus permitting more precise prediction of the mechanical properties that determine bread texture.
Effect of Aelia spp. and Eurygaster spp. Damage on Wheat Proteins
Authors: Rosell C. M. , Aja S. , Bean S. , Lookhart G.
Published: June 2007

The effect of Aelia spp. and Eurygaster spp. wheat bugs on the protein fractions of different wheat cultivars has been studied by size‐exclusion high‐performance liquid chromatography (SE‐HPLC) and free‐zone capillary electrophoresis (FZCE). Those methods were used to quantify and characterize the extent of protein modification. A decrease in the amount of alcohol‐insoluble polymeric proteins along with an increase in the alcohol‐soluble polymeric proteins and gliadins were observed in damaged wheat. The high molecular weight (HMW) and low molecular weight (LMW) glutenin fractions were barely detected in the incubated damaged wheat from some cultivars, which indicated hydrolysis of those proteins by the bug proteinases. In damaged wheats, both incubated and unincubated, gliadin electrophoregrams revealed the presence of some new peaks with mobilities similar to the ω gliadins. The overall results suggest that the bug proteinases are potent enzymes that appear to be nonspecific because they hydrolyze all gluten proteins.
Measurement of Cooked Noodle Stickiness Using a Modified Instrumental Method
Authors: Lee Seung Ju , Rha Mikyoung , Koh Wonbang , Park Woojoon , Lee Chiho , Kwon Young An , Hwang Jae‐Kwan
Published: June 2007

Stickiness of cooked noodles, generally defined as a maximum force in tension after compression, depends on the compression force, contact area, and physical properties of the noodles. In the conventional method of measuring stickiness, only compression force was set as a standard, neglecting the other probable influencing factors. A modified method was developed for measuring contact area between noodles and a probe, in addition to the compression force. Four specimens with varying starch contents (0, 30, 60, and 90%) were tested to evaluate the new method for measuring cooked noodle stickiness. Contact area calculated from the displacement of probe at the compression condition was not consistent among the noodle samples. A corrected stickiness and a corrected compression force were defined as a simple stickiness directly measured for the contact area and the compression force measured for the contact area, respectively. This method proved to be a more effective means in differentiating the stickiness among noodle samples (than using just compression force factors). The order in the corrected stickiness magnitudes among the noodles was consistent regardlessof specimen amount used in the measurements, whereas that of the simple stickiness was inconsistent when different size samples were used. The corrected compression force estimated from a fixed simple compression force, which is a true compression stress, varied among the noodles. Accordingly, the corrected compression force was a more accurate criteria for stickiness measurements than was the simple compression force, which subjects the specimens to only differences in compression for stickiness comparison. The corrected stickiness results showed greater relationship to sensory stickiness and starch content than the simple stickiness measurement.
Invisible Coatings for Wheat Kernels
Authors: Ram M. S. , Dowell Floyd E. , Seitz Larry
Published: June 2007

It is occasionally necessary to tag wheat kernels without altering their appearance. Coatings have potential applications to tag wheat of a particular color or protein class, diseased wheat such as Karnal bunt, or genetically modified wheat. This methodology will aid in development of calibrations for sorting instruments. Procedures were developed to coat wheat kernels with invisible ultraviolet (UV) fluorescent and near‐infrared (NIR) absorbing noncarcinogenic dyes. Wheat coated with UV‐fluorescent compounds were identified under black light. The NIR‐absorbing coating required lower concentrations of dye than the UV dyes and wheat coated with NIR‐absorbing dye were identified from their NIR spectrum.
Biochemical Characterization and Quantification of the Storage Protein (Secalin) Types in Rye Flour
Authors: Gellrich Claudia , Schieberle Peter , Wieser Herbert
Published: June 2007

Kernels of the rye cultivars Danko and Halo were milled into white flour and compared with flour of the wheat cultivar Rektor. Flour proteins were extracted stepwise with a salt solution (albumins‐globulins), 60% ethanol (prolamins), and 50% 2‐propanol under reducing conditions (glutelins). The quantification by reversed‐phase HPLC indicated that the extractable proteins of both rye flours consisted of ≈26% albumins‐globulins, 65% prolamins, and 9% glutelins. Compared with wheat flour, rye flours comprised significantly higher proportions of nonstorage proteins (albumins‐globulins) and lower proportions of polymerized storage proteins (glutelins). SDS‐PAGE revealed that the prolamin fractions of rye contained all four storage protein types (HMW, γ‐75k, ω, and γ‐40k secalins), whereas the glutelin fractions contained only HMW and γ‐75k secalins. The quantification of secalin types by RP‐HPLC showed a close relationship between the two cultivars.The γ‐75k secalins contributed nearly half (≈46%) of the total storage proteins, followed by γ‐40k secalins (24%) and ω secalins (17%); HMW secalins (≈7%) were minor components, and 6% of eluted proteins were not identified. The amino acid composition of γ‐40k secalins corresponded to those of γ‐gliadins of wheat, whereas γ‐75k secalins were characterized by higher contents of glutamine and proline. Matrix‐assisted laser desorption/ionization and time of flight mass spectrometry (MALDI‐TOF MS) indicated molecular masses of about 52,000 (γ‐75k) and 32,000 (γ‐40k), respectively. N‐terminal amino acid sequences were homologous with those of wheat γ‐ gliadins except for position 5 (asparagine in γ‐75k and glutamine in γ‐40k secalins) and position 12 (cysteine in γ‐75k secalins). The N‐terminal amino acid sequences of HMW and ω‐secalins were homologous with those of the corresponding protein types of wheat. Gel‐permeation HPLC of prolamin fractions revealed that rye flours contained a significantly higher proportion of ethanol‐soluble oligomeric proteins than wheat flour.
Instrumental and Sensory Assessment of Oatmeal and Chocolate Chip Cookies Modified with Sugar and Fat Replacers
Authors: Perry J. M. , Swanson R. B. , Lyon B. G. , Savage E. M.
Published: June 2007

Sensory texture and flavor parameters of three formulations of two popular cookies were evaluated by a trained descriptive panel. Probing, a puncture test, was used to assess texture instrumentally. Other physical tests included water activity, cookie spread, and specific gravity. Chocolate chip and oatmeal cookies were prepared using a nonsucrose sweetener blend (dextrose/acesulfame‐K) or prune puree, following manufacturers' recommendations, to replace 50% of the sugar or fat, respectively. The three formulations differed in ratios of flour, sugar, fat, and water. Instrumental and sensory evaluations occurred the day after baking. Data were analyzed using analysis of variance and means separation tests (P < 0.05). Relationships between sensory and instrumental assessments were identified with correlations. According to the trained panel, sugar and fat replacement had a greater effect on texture than on flavor. Probing was successfully used to assess textural attributes of cookies. Correlations revealed that the area under the curve was the best predictor of sensory hardness and chewiness, regardless of cookie type.
Influence of Structural Characteristics of Aleurone Layer on Milling Behavior of Durum Wheat (Triticum durum Desf.)
Authors: Peyron S. , Mabille F. , Devaux M. F. , Autran J. C.
Published: June 2007

The structure of the aleurone layer was considered for many years as a potential factor influencing wheat milling efficiency. Eight durum wheat samples of different milling values, including distinct cultivars and harvesting conditions, were employed to investigate the structural characteristics of the aleurone layer through image analysis of kernel sections. Particular attention was paid to tissue thickness and structural irregularity of its interface with the starchy endosperm. Wheat cultivar, agricultural conditions, and location of measurement within the grain had an influence similar to both thickness and irregularity of the aleurone layer. Conversely, grain weight and morphology showed no effect on these parameters. Statistical investigation demonstrated no correlation between structural characteristics and wheat milling behavior. However, the negative correlation between the extraction rate of semolina and starch content in the bran fraction, which was used as an indicator of the endosperm‐aleurone dissociation extent, demonstrated the relevance of the tissue adhesion on milling efficiency.
Fructan Content of Rye and Rye Products
Authors: Karppinen S. , Myllymäki O. , Forssell P. , Poutanen K.
Published: June 2007

The fructan content of Finnish rye grains (13 samples, seven cultivars, harvested in 1998‐2000) varied at 4.6–6.6 g/100 g (db). Commercial whole grain rye flour and rye flakes had fructan content of 4 g/100 g, light refined rye flour had fructan content of 3 g/100 g, and rye bran had fructan content of 7 g/100 g. Fructan content as high as 23 g/100 g was detected in the water‐extractable concentrate of rye bran. Finnish soft rye bread and rye crisp bread contained 2–3 g of fructan/100 g. According to the suggested new definition of dietary fiber, fructans are also classified as dietary fiber. This means that the dietary fiber content of some cereal foods such as rye products may be increased by as much as 20% due to the presence of fructans in the grain.
l‐Arabinose Release from Arabinoxylan and Arabinogalactan Under Potential Gastric Acidities
Authors: Zhang Pingyi , Zhang Qian , Whistler Roy L.
Published: June 2007

Arabinofuranosyl groups are present in many hemicelluloses as single or multiple units attached to the main xylan or galactan chain where they are sensitive to acid hydrolysis. Under acidic conditions of the human stomach, up to 10% of the L‐arabinose is released from the hemicellulose of corn hull, larch wood, and banana peel hemicellulose.
Effect of Physical States of Nonpolar Lipids on Rheology, Ultracentrifugation, and Microstructure of Wheat Flour Dough
Authors: Watanabe Akihiro , Yokomizo Kazuhisa , Eliasson Ann‐Charlotte
Published: June 2007

In the previous study, we investigated effect of physical state of nonpolar lipids of gluten‐starch model dough. This experiment examined a real wheat flour dough system to assess the role of fat crystals in the breadmaking processes. These experiments were performed with a baking test and an investigation of wheat flour dough through rheological measurements (both large and small deformations), scanning electron microscopy, and ultracentrifugation. As a result, we found that the added oil was absorbed in the gluten structure, causing the aggregation of the gluten, which gave rise to more elastic behavior. In contrast, solid fat seemed to be distributed uniformly between the starch granules in the dough, reducing the friction between the starch granules and facilitating thin gluten gel layers. These properties lead to the lower G′ value and the increased viscous behavior, which yields an increase in loaf volume. In addition, the supposed mechanism behind the large loaf volume described in the previous study was that fat provides a uniform distribution of the dough components, and that the dough can thus expand easily, resulting in a larger loaf volume, which was supported in the wheat flour dough system. In conclusion, we found that thin, expandable gluten films and the uniform dispersion of gluten and starch granules in the dough are prerequisites for attaining better baking performance.