bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Liquid Nitrogen Freeze Drying and Ethanol Dehydration as Methods to Preserve Partially Cooked Starch and Masa Systems
Authors: Yglesias Roxana , Jackson David S.
Published: June 2007

Preservation of starch structure/properties, including structures formed during partial or complete cooking, are important when the impact of processing conditions is being studied. Two preservation techniques used to study changes in starch during thermal‐mechanical processing are commonly cited in the literature: 1) rapid freezing followed by lyophilization, and 2) a dehydration procedure using alcohols. A comparative determination on how these methods affect various starch structures has not been widely reported. Corn starch samples were collected from the Rapid Visco‐Analyser (RVA) at 3 min (swollen granules, 30°C), at the top of the pasting peak (gelatinized granules, 95°C), at the bottom of the trough (dispersed polymers, 95°C), and a completed RVA sample stored for 120 hr at 4°C (retrograded starch). Samples of masa were obtained by nixtamalizing corn. Differential scanning calorimetry (DSC) endotherms of starch and masa, and X‐ray diffraction (XRD) patterns of masa were evaluated after being preserved by alcohol‐ or freeze‐drying. No significant differences (P > 0.05) between methods were found for onset, end, and peak temperatures (°C), enthalpy (J/g) and % relative crystallinity in any of the samples analyzed. Liquid nitrogen freeze‐drying and ethanol dehydration are both effective methods of preserving various starch systems for structural changes detectible by DSC and XRD; freeze‐drying is generally less expensive and time‐consuming.
Molecular Level Protein Composition of Flour Mill Streams from a Pilot‐Scale Flour Mill and Its Relationship to Product Quality
Authors: Sutton K. H. , Simmons L. D.
Published: June 2007

Flour mill streams prepared from two Australian and two New Zealand wheat cultivars using a pilot‐scale roller mill were analyzed for rheological and baking quality characteristics and for protein composition using size‐exclusion HPLC. Differences in mill stream protein composition, on an industrially relevant scale, and the relationships between the distribution of proteins (and their degree of thiol exposure) and the technological quality of the flour mill streams were examined. Consistent, significant differences were observed in the physicochemical and processing characteristics of the flour streams. Between mill streams, changes in the quantities of the storage protein groups were more marked than for nonstorage protein groups. Changes in protein composition differed between the break and reduction stream flours. In contrast, the degree of exposure of thiol groups on the various protein groups followed different patterns between mill streams. Numerous significant relationships were observed between dough mixing and product baking tests and the composition and thiol exposure state of the various protein classes. These relationships are discussed in context of manipulating the processing quality of flour‐based products using mill streaming. A possible role for exposed thiol groups on storage proteins in the phenomenon of flour “aging” is suggested.
Oat Grain/Groat Size Ratios: A Physical Basis for Test Weight
Authors: Doehlert D. C. , McMullen M. S. , Jannink J.‐L.
Published: June 2007

Market value of oat grain is largely determined by test weight or bulk density, yet little is known of the physical basis for test weight in oats. We have hypothesized that a larger sized groat relative to the oat grain (the kernel with the hull) would generate higher test weight oats because the groat is the densest structure in the oat grain. We tested this by measuring oat grain size and oat groat size by digital image analysis for 10 genotypes grown in 10 environments. We also measured other physical characteristics of the oats grains and groats including mean grain and groat mass, test weight, and groat percentage. We found that the groat/ grain size ratio was highly correlated with test weight. Because the oat grain image area was nearly twice that of the groat, we suggest that there are significant amounts of empty space within the oat hull, which detracts from test weight. We also found that oat groat size distributions, like oat grains, fit bimodal distributions better than normal distributions.
Analysis of Heat Transfer Fouling by Dry‐Grind Maize Thin Stillage Using an Annular Fouling Apparatus
Authors: Wilkins M. R. , Belyea R. L. , Singh V. , Buriak P. , Wallig M. A. , Tumbleson M. E. , Rausch K. D.
Published: June 2007

In dry‐grind processing to produce ethanol from corn, unfermented solids are removed from ethanol by distillation and dried to produce distillers dried grains with solubles (DDGS), an animal food. Fouling of thin stillage evaporators has been identified as an important energy consumption issue in dry‐grind facilities. Using an annular fouling apparatus, four batches of thin stillage were analyzed to determine repeatability of fouling rate and induction period measurements. Dry solids, protein and ash concentrations, and pH were correlated to fouling rate and induction period to determine how variation in thin stillage from the same dry‐grind facility affects these fouling parameters. Effects of increasing Reynolds number (Re) in the laminar region on fouling rate, induction period, and fouling deposit protein and ash concentrations were also determined. Repeatability of fouling rate measurements was similar to other studies (CV < 7.0%) but repeatability of induction period measurements was high relative to other studies (CV < 88.7%). Fouling rate increased with increasing dry solids concentration. Thin stillage at Re = 440 had shorter induction periods and greater fouling rates than at Re = 880. Fouling deposits collected from Re = 440 tests had similar protein concentrations and lower ash concentrations compared with deposits from Re = 880 tests.
Changes in Secondary Protein Structures During Mixing Development of High Absorption (90%) Flour and Water Mixtures
Authors: Robertson G. H. , Gregorski K. S. , Cao T. K.
Published: June 2007

Wheat flour and water mixtures at 90% absorption (dry flour basis) prepared at various mixing times were examined using Fourier transform infrared (FT‐IR) reflectance spectroscopy. Spectra were obtained using a horizontal attenuated total reflection (ATR) trough plate. The apparent amount of protein and starch on the surface of the dough varied with mixing time but this was likely due to the polyphasic nature of the substrate and the changing particle distributions as the batter matrix was developed. Deconvolution of the Amide I band revealed contributions from alpha helical, β‐turn, β‐strand, β‐sheet, and random conformations. The ratio of β‐sheet to nonsheet conformations reached its greatest value about the same time that the mixture was most effectively separated by a laboratory‐scale, cold‐ethanol‐based method but before the peak consistency measured by a microfarinograph.
Composition and Distribution of Pentosans in Millstreams of Different Hard Spring Wheats
Authors: Wang Mingwei , Sapirstein Harry D. , Machet Anne‐Sophie , Dexter James E.
Published: June 2007

Six commercially grown samples of hard spring wheat were milled using a tandem Buhler laboratory mill. Individual flour streams and branny by‐products, as well as whole‐grain wheat and straight‐grade flour, were characterized in terms of total (TP), water‐extractable (WEP), and water‐unextractable (WUP) pentosans. One representative cultivar sample was analyzed for its ratio of arabinose to xylose (A/X). TP and WEP of whole grain wheat of the six samples had ranges of 5.45–7.32% and 0.62–0.90% (dm), respectively. Neither TP nor WEP of whole grain was related to ash content variation. There was significant variation in the distribution and composition of pentosans in 16 millstreams of all the wheat samples, including bran and shorts fractions; TP and WEP contents had ranges of 1.69–32.4% and 0.42–1.76% (dm), respectively. When ash contents exceeded ≈0.6% (dm), strong positive correlations were obtained between ash and TP contents, and between ash and WUP contents for all the millstreams. Among bran and shorts fractions, TP and WUP content increased in the order of coarse bran > fine bran > shorts; while WEP, WEP/WUP and A/X showed the opposite pattern of variation of shorts > fine bran > coarse bran. Bran and shorts fractions had pentosan contents several times higher than would be predicted from the relationship between pentosan and ash contents of the flour streams. Pentosans therefore represented a much more sensitive marker of flour refinement compared with ash content. Pentosans of endosperm were substantially different in their extractability and composition from those of bran. On this basis, different functionalities of pentosans of bran and endosperm would be expected. Results demonstrated the importance of milling extraction and millstream blending in the functionality and quality of wheat flour for breadmaking.
Use of Solvent Retention Capacity Profile to Predict the Quality of Triticale Flours
Authors: Roccia P. , Moiraghi M. , Ribotta P. D. , Pérez G. T. , Rubiolo O. J. , León A. E.
Published: June 2007

The solvent retention capacity test (SRC) was used to evaluate flour functionality for end use applications and select wheat for production of flour with required functionality, but there is little information about SRC test application on triticale flour quality. The ability of flour to retain a set of four solvents produces a flour quality profile for predicting bakery performance. The objective of this study was to evaluate the capacity of SRC and its micro test to determine the potential quality of 25 triticale flours, as well as studying the relationship between the SRC parameters and flour chemical composition. The SRC parameters of triticale flours were correlated with the flour components that have been proposed by the method: sucrose SRC‐pentosan (r = 0.57), carbonate SRC‐damaged starch (r = 0.80), lactic SRC‐glutelin (r = 0.42), water SRC‐all hydrophilic constituents (damaged starch [r = 0.72], protein [r = 0.61], glutelin [r = 0.66], pentosan [r = 0.46]). Triticale flours have shown higher water and sodium carbonate SRC, similar sucrose SRC, and lower lactic SRC values than published results of typical flours used for cookie production. Summarizing, the high level of association found between SRC and micro SRC parameters with flour composition and quality flour tests evidence that either the SRC profile or the micro test SRC could be used to determine the potential quality of triticale flours.
Predicting Rice Physicochemical Properties Using Thickness Fraction Properties
Authors: Siebenmorgen T. J. , Bautista R. C. , Meullenet J.‐F.
Published: June 2007

Long‐grain rice cultivars Francis and Wells and hybrid XL8 Clearfield were harvested from two locations at three harvest moisture contents (HMC) in 2003. The rough rice was dried, fractionated into thin, medium, and thick fractions, and milled. Physicochemical properties of unfractionated and fractionated samples were determined. The effects of HMC and location on thickness distributions were investigated and the weighted‐average physicochemical properties of the thickness fractions were compared with those of unfractionated rice. Generally, the growing location and HMC affected kernel thickness distributions, green kernel content, fissured kernel content, and head rice yield (HRY). As kernel thickness within samples increased, amylose content increased and the protein content and α‐amylase activity decreased. Thick fractions had greater peak viscosities than medium and thin fractions. The thin, medium, and thick fraction physicochemical property weighted averages provided good predictions of most unfractionated rice sample properties. However, this approach was not entirely accurate for predicting HRY, milled rice total lipid content, and bulk density.
Single Kernel Near‐Infrared Analysis of Tetraploid (Durum) Wheat for Classification of the Waxy Condition
Authors: Delwiche Stephen R. , Graybosch Robert A. , Hansen Lavern E. , Souza Edward , Dowell Floyd E.
Published: June 2007

Plant breeding programs are active worldwide in the development of waxy hexaploid (Triticum aestivum L.) and tetraploid (T. turgidum L. var. durum) wheats. Conventional breeding practices will produce waxy cultivars adapted to their intended geographical region that confer unique end use characteristics. Essential to waxy wheat development, a means to rapidly and, ideally, nondestructively identify the waxy condition is needed for point‐of‐sale use. The study described herein evaluated the effectiveness of near‐infrared (NIR) reflectance single‐kernel spectroscopy for classification of durum wheat into its four possible waxy alleles: wild type, waxy, and the two intermediate states in which a null allele occurs at either of the two homologous genes (Wx‐1A and Wx‐1B) that encodes for the production of the enzyme granule bound starch synthase (GBSS) that controls amylose synthesis. Two years of breeders' samples (2003 and 2004), corresponding to 47 unique lines subdivided about equally into the four GBSS genotypes, were scanned in reflectance (1,000–1,700 nm) on an individual kernel basis. Linear discriminant analysis models were developed using the best set of four wavelengths, best four wavelength differences, and best four principal components. Each model consistently demonstrated the high ability (typically >95% of the time) to classify the fully waxy genotype. However, correct classification among the three other genotypes (wild type, wx‐A1 null, and wx‐B1 null) was generally not possible.
Quantitative Glutenin Composition from Gel Electrophoresis of Flour Mill Streams and Relationship to Breadmaking Quality
Authors: Wang Y. G. , Khan K. , Hareland G. , Nygard G.
Published: June 2007

Three samples of Nekota (hard red winter wheat) were milled, and six mill streams were collected from each sample. The 18 mill streams were analyzed separately as well as recombined to form three patent flours. The methods of multistacking (MS)‐SDS‐PAGE and SDS‐PAGE were used to separate the unreduced SDS‐soluble glutenins and the total reduced proteins, respectively. The separated proteins were quantified by densitometry. The quantity of unreduced SDS‐soluble proteins was significantly different among the mill streams at the 4% (largest molecular weight polymeric glutenins) and at the 10 and 12% (smaller molecular weight polymeric glutenins) origins of the MS‐SDS‐PAGE gels. The quantities of total HMW‐GS, LMW‐GS, 2*, 7+9, and 5+10 subunits and the ratio of HMW‐GS to LMW‐GS in polymeric protein samples isolated using preparative MS‐SDS‐PAGE and in total reduced protein extracts were significantly different among mill streams. The quantities of HMW‐GS, LMW‐GS, 2*, 7+9, and 5+10 subunits from total reduced proteins were positively and significantly correlated with loaf volume. The quantities of glutenin subunits (both HMW‐GS and LMW‐GS) from unreduced SDS‐soluble proteins were positively or negatively correlated with loaf volume at the various MS‐SDS‐PAGE gel origins but the levels of correlation were not significant. These results showed that the glutenin protein composition was different among the various mill streams and demonstrated that electrophoretic analysis of the proteins in these fractions is a useful tool for studying the variation in functional properties of flour mill streams.
Effects of Processing Conditions on Nanoclay Dispersion in Starch‐Clay Nanocomposites
Authors: Chiou Bor‐Sen , Yee Emma , Wood Delilah , Shey Justin , Glenn Greg , Orts William
Published: June 2007

Wheat starch samples containing Cloisite Na+ and 30B nanoclays were extruded from a twin‐screw extruder. Moisture content, temperature, and screw speed were varied to determine their effect on nanoclay dispersion. X‐ray diffraction and transmission electron microscopy (TEM) were used to examine nanoclay intercalation and exfoliation. Moisture content had the largest effect on Cloisite Na+ dispersion, with the highest moisture sample containing exfoliated nanoclays. Meanwhile, temperature and screw speed had little effect on Cloisite Na+ dispersion. For Cloisite 30B samples, only an increase in temperature produced slight intercalation of nanoclays. This was due to the incompatibility of starch with the more hydrophobic Cloisite 30B. Also, Cloisite Na+ and 30B intercalation did not depend on specific mechanical energy. In addition, water absorbance tests indicated the Cloisite Na+ sample containing the most well‐dispersed nanoclays had the lowest water uptake.
Influence of Rice Proteins on Eating Quality of Cooked Rice and on Aroma and Flavor of Sake
Authors: Furukawa Sachiko , Tanaka Kunisuke , Masumura Takehiro , Ogihara Yasunari , Kiyokawa Yoshifumi , Wakai Yoshinori
Published: June 2007

An improved method for the extraction of storage proteins from rice endosperm under conditions safe for producing food was developed. The contribution of the protein extracts to the eating quality of cooked rice and to the aroma and flavor of sake was examined. Sensory analysis was performed to evaluate the eating quality of cooked rice enriched with the protein extracts. Prolamin‐enrichment increased the hardness of cooked rice, and glutelin‐enrichment degraded the appearance of cooked rice. Physical analyses confirmed that prolamin‐enrichment changed, whereas the glutelin‐enrichment did not change the physical properties of cooked rice. Light and scanning electron microscopy of rice protein extracts revealed small particles of the prolamin extract and larger aggregated particles of the glutelin extract; these features remained after heating. The aroma and flavor of sake were negatively affected by the addition of the protein extracts. Especially, addition of prolamin significantly lowered the evaluation score of the aroma obtained by sensory analysis.
Effects of Four Independent Low‐Phytate Mutations in Barley (Hordeum vulgare L.) on Seed Phosphorus Characteristics and Malting Quality
Authors: Bregitzer Phil , Raboy Victor
Published: June 2007

Conversion of the seed phosphorus storage compound phytic acid, which is poorly digested by nonruminants, to available forms of phosphorus will have nutritional and environmental benefits. Low‐phytate (LP) barley (Hordeum vulgare L.) cultivars are in development and their commercialization will be facilitated by understanding their phosphorus profiles and malting quality. To study these issues, LP and normal types derived from mutagenized populations of barley cultivar Harrington (sets of sib lines homozygous for the wild‐type [WT] allele, or for one of four low‐phytic acid mutations, lpa1‐1, lpa2‐1, lpa3‐1, or M955), were developed through backcrosses to Harrington. Grain was produced in irrigated and rain‐fed environments. WT phosphorus profiles were similar to those of Harrington, suggesting that the major variable was the presence or absence of mutant alleles. All mutations conferred increased inorganic phosphorus. Total P was reduced for lpa1‐1. Phosphorus profiles were relatively stable across environments, which will facilitate the inclusion of LP barley in animal rations. Utilization of LP cultivars for malting may be difficult, as the LP trait was associated with substantial reductions in diastatic power. All mutations, except for lpa2‐1, affected wort β‐glucan levels, which could not be attributed to altered grain β‐glucan levels.
Development of a Near‐Infrared Imaging System for Determination of Rice Moisture
Authors: Lin Lian‐Hsiung , Lu Fu‐Ming , Chang Yung‐Chiung
Published: June 2007

The objective of this study was to develop a near‐infrared (NIR) imaging system to determine rice moisture content. The NIR imaging system fitted with 15 band‐pass filters (wavelengths of 870–1,014 nm) was used to capture the spectral image. In this work, calibration methods including multiple linear regression (MLR), partial least squares regression (PLSR), and artificial neural network (ANN) were used in both near‐infrared spectrometry (NIRS) and the NIR imaging system to determine the moisture content of rice. Comprehensive performance comparison among MLR, PLSR, and ANN approaches has been conducted. To reduce repetition and redundancy in the input data and obtain a more accurate network, six significant wavelengths selected by the MLR model, which had high correlation with the moisture content of rice, were used as the input data of the ANN. The performance of the developed system was evaluated through experimental tests for rice moisture content. This study adopted the coefficient of determination (rval2), the standard error of prediction (SEP), and the relative performance determinant (RPD) as the performance indices of the NIR imaging system with respect to the tests of rice moisture content. Utilizing these three models, the analysis results of rval2, SEP, and RPD for the validation set were within 0.942–0.952, 0.435–0.479%, and 4.2–4.6, respectively. From experimental results, the performance of NIR imaging system was almost the same as that of NIRS. Using the developed NIR imaging system, all of the three different calibration methods (MLR, PLSR, and ANN) provided a high prediction capacity for the determination of moisture in rice samples. These results indicated that the NIR imaging system developed in this study can be used as a device for the measurement of rice moisture content.
An Automated Near‐Infrared System for Selecting Individual Kernels Based on Specific Quality Characteristics
Authors: Dowell F. E. , Maghirang E. B. , Graybosch R. A. , Baenziger P. S. , Baltensperger D. D. , Hansen L. E.
Published: June 2007

An automated sorting system was developed that nondestructively measured quality characteristics of individual kernels using near‐infrared (NIR) spectra. This single‐kernel NIR system was applied to sorting wheat (Triticum aestivum L.) kernels by protein content and hardness, and proso millet (Panicum miliaceum L.) into amylose‐bearing and amylose‐free fractions. Single wheat kernels with high protein content could be sorted from pure lines so that the high‐protein content portion was 3.1 percentage points higher than the portion with the low‐protein kernels. Likewise, single wheat kernels with specific hardness indices could be removed from pure lines such that the hardness index in the sorted samples was 29.4 hardness units higher than the soft kernels. The system was able to increase the waxy, or amylose‐free, millet kernels in segregating samples from 94% in the unsorted samples to 98% in the sorted samples. The portion of waxy millet kernels in segregating samples was increased from 32% in the unsorted samples to 55% after sorting. Thus, this technology can be used to enrich the desirable class within segregating populations in breeding programs, to increase the purity of heterogeneous advanced or released lines, or to measure the distribution of quality within samples during the marketing process.
Role of Blowing Agents in Expansion of High‐Amylose Starch Acetate During Extrusion
Authors: Ganjyal Girish M. , Hanna Milford A.
Published: June 2007

High‐amylose starch acetate (DS 2) was processed in a Brabender twin‐screw extruder with ethanol and isopropanol as blowing agents at concentrations of 0, 2, 5, 10, 15, and 25%. A constant temperature of 150°C, a constant screw speed of 140 rpm, and a die nozzle with diameter of 4.0 mm and length of 16.2 mm were used to study the role of blowing agents on the expansion of the extrudates. Extrudates without blowing agent shrunk considerably after exiting the die as the cells collapsed drastically after expansion. Stable radial expansion of the extrudates increased with increase in the ethanol concentration to an optimum value of 18.0 at 5% (db) ethanol concentration and decreased with further increase in the ethanol concentration. Stable radial expansion increased to a maximum of 17.0 as the concentration of isopropanol was increased to 25% (db), though the rate of increase in expansion decreased with the increase in isopropanol concentration >10%. Flashing off of blowing agents aided in removing the heat generated during extrusion. The faster the extrudate cooled, the less likely it was to shrink. SEM were used to observe the effects of concentration of blowing agents on cell morphology. Various phenomena involved during the expansion are discussed. To obtain an extrudate with high expansion and low density, isopropanol at 15–25% (db) was found most suitable in this study.
Kernel Microstructure of Latin American Races of Maize and Their Thermal and Rheological Properties
Authors: Narváez‐González Ernesto David , de Dios Figueroa‐Cárdenas Juan , Taba Suketoshi , Sánchez Froylán Rincón
Published: June 2007

Seventy‐one races of maize representing races from Latin America were analyzed for microstructural features such as the degree of compaction of the endosperm cell bodies, starch granule size and morphology, and hard‐soft endosperm relationship. Flours were analyzed using rapid visco analysis and differential scanning calorimetry. Compaction grade was the most important microstructural feature of the maize kernels that related to thermal and rheological properties. Highly compact kernels developed low peak and final viscosities; small, polygonal starch granules; and required more time and higher temperature to gelatinize. The opposite was the case for less compact kernels. This indicates that the characteristic protein matrix of highly compact kernels represents a physical barrier to water migration into the granules, retarding the gelatinization process.
Rapid Isolation of Sorghum and Other Cereal Starches Using Sonication
Authors: Park S. H. , Bean S. R. , Wilson J. D. , Schober T. J.
Published: June 2007

High‐intensity ultrasound (sonication) was investigated as a method to rapidly purify starch from sorghum and other cereal grains. To improve the process, buffers were optimized to solubilize sorghum proteins in combination with the sonication. Protein content and starch color were determined to evaluate the efficiency of the extraction process. Sonication times, SDS concentration, different types and concentrations of reducing agents (sodium metabisulfite, dithiothreitol, and β‐mercaptoethanol), and centrifugation speeds of the starch washing procedure were tested. Protein content of isolated sorghum starch was reduced to 0–0.14% (db) after 2 min of sonication (using any of the reducing agents tested). Sodium metabisulfite was chosen as the preferred reducing agent because of its lower toxicity and odor compared with other reducing agents tested. The optimum conditions for producing high‐purity sorghum starches (0.06% protein) were obtained using the following conditions: 2 min of sonication time with 12.5 mM sodium borate buffer, pH 10, containing 0.5% SDS (w/v) and 0.5% sodium metabisulfite (w/v) using 1,500 rpm centrifugation speed during starch washing. Starches separated by this method showed significantly less protein content and b values (yellowness) compared with starches separated by enzymatic methods or methods using NaCl solutions and protein extraction buffers with multiple washing steps, both of which take several hours to complete. Differential scanning calorimetry thermogram values for starches isolated by three different methods showed similar patterns, except that starches obtained with the enzymatic method had slightly higher values of To, Tp, and ΔH. Other cereal starches from whole wheat meal, wheat flour, corn, rice, and barley were also obtained rapidly using sonication.
Water Absorption Characteristics and Volume Changes of Milled and Brown Rice During Soaking
Authors: Muramatsu Y. , Tagawa A. , Sakaguchi E. , Kasai T.
Published: June 2007

The water absorption characteristics and volume changes of rice with various degrees of milling during soaking were measured at five temperatures (5–40°C). The measured data were fitted to the exact solution for the infinite plane sheet diffusion model, which is an exact solution for the diffusion equation. The measured results agreed well with the model. The effects of temperature and the degree of milling on the water absorption rate constant were investigated. Volume changes of samples were determined by measuring particle density and bulk density. An empirical equation relating the moisture content of the sample during soaking and at temperatures of 10–50°C to specific volume was derived. In addition, bulk density was related to the quadratic function of the moisture content of the sample during soaking.
Dynamic Monitoring of Dough Mixing Using Near‐Infrared Spectroscopy: Physical and Chemical Outcomes
Authors: Kaddour A. Aït , Barron C. , Morel M.‐H. , Cuq B.
Published: June 2007

The objective of the present study was to identify physical, chemical, and physicochemical mechanisms at the origin of the NIR spectra modifications recorded during dough mixing. An FT‐NIR spectrometer over the 1000–2500 nm range with a fiber optic probe in contact with the dough during processing was used. The NIR spectra collections are analyzed as raw spectra and after second derivative treatment by using principal component analysis (PCA). The analysis of the three first principal components describe high cumulative variance (>95%). The PCA on the raw NIR spectra demonstrate the dominant contribution of physical mechanisms (granular state and surface aspect of the dough) and, to a lesser extent, of physicochemical mechanisms (water and protein modifications). The PCA of the second derivative spectra on the 1000–2325 nm wavelength range and on restricted wavelength ranges (1352–1485 nm, 1778–2052 nm, or 2109–2325 nm) allowed a physicochemical description of the NIR absorbance variations. The NIR absorbance variations mainly arise from the 1778–2052 nm range related to the O‐H vibrations. NIR mixing times were determined from the PCA score plots based on raw and second derivative NIR spectra and were associated with changes in different dough physicochemical properties (glutenin depolymerization rate, extractable liquid phase, consistency, maximum strain, and stress at break).
Detection of Genetically Modified Soy in Doughs and Cookies
Authors: Gryson Nicolas , Dewettinck Koen , Messens Kathy
Published: June 2007

In many countries, including the European Union member states, Switzerland, Australia, New Zealand, and Japan, legislation has been set up for labeling of genetically modified organisms (GMOs) in food and feed products. To comply with these regulations, reliable detection methods are necessary. If the detection is based on DNA, a GMO analysis may contain several steps where qualitative and quantitative species‐specific, GMO screening, GMO construct, and GMO line‐specific polymerase chain reactions (PCRs) are used. A limit of detection (LOD) thereby defines to what extent a target molecule may be detected in a sample. In this study, cookies were made with variable levels of a soy sample containing 2 wt% Roundup Ready soy. For all PCRs described, detection limits based on dilution series and practical LODs were determined. The practical LODs are used to determine to what extent a GMO ingredient may be detected in a real food product. Results reveal that, due to the baking process, the overall DNA fragment length is reduced, rendering GMO analyses more difficult. Furthermore, Roundup Ready soy line‐specific and real‐time quantitative PCR are less sensitive than GMO screening PCRs, whereas just these PCRs are crucial in the decision‐making process regarding the presence of GMOs in a food product. Moreover, high standard deviations and errors render the precise quantification of GMOs difficult.
Study of Calcium Ion Diffusion in Nixtamalized Quality Protein Maize as a Function of Cooking Temperature
Authors: Gutierrez E. , Rojas‐Molina I. , Pons‐Hernandez J. L. , Guzman H. , Aguas‐Angel B. , Arenas J. , Fernandez P. , Palacios‐Fonseca A. , Herrera G. , Rodríguez M. E.
Published: June 2007

In this report, the effect of temperature on the calcium content of Quality Protein Maize (QPM H‐368C) during the nixtamalization process as a function of the steeping time for three cooking temperatures (72, 82, and 92°C) is presented. Also, for the first time, we report in physico‐chemical terms the end of the cooking stage during the nixtamalization process that was established when the moisture content in corn kernels reached a value of 36% (w/w) with a lime concentration of 1% (w/v), independent of the cooking temperature. Atomic absorption spectroscopy was used to determine the calcium concentration in the whole kernel and in its different anatomical components (pericarp, endosperm, and germ) as well as in 10% of the outermost layers, the next 10%, and the remaining 80% of the endosperm as a function of the steeping time. It was found that if the cooking temperature increases, the calcium content increases also. For steeping times in the range of 5–7 hr, a relative maximum was found in the calcium contents of 0.24, 0.21, and 0.18% (w/w) in QPM H‐368 flours at 92, 82, and 72°C, respectively. Calcium was found in the most external layers in the endosperm and minimum diffusion occurs in the internal 80%. Phosphorous was measured by using UV spectroscopy and the results showed that it remains constant at 0.24% throughout the process. Scanning electron microscopy analysis was used to explain the calcium ion diffusion in the kernel. The physical changes in the pericarp govern the calcium diffusion process.
Functional Characteristics of Extruded Blends of Whey Protein Concentrate and Corn Starch
Authors: Amaya‐Llano S. L. , Hernández N. Morales , Tostado E. Castaño , Martínez‐Bustos F.
Published: June 2007

The aim of this work was to study the effects of extrusion barrel temperature (70–180°C), feed moisture (18–30%), pH (3–8), different proportions of corn starch (75–95%), and whey protein concentrate (WPC, 80% protein concentration) (25–5%) on the preparation of functional blends. Expansion index (EI), bulk density (BD), compression force (CF), color, water absorption index (WAI), water solubility index (WSI), gel strength (GS), syneresis of the gel, and in vitro digestibility were evaluated. Barrel temperature and the proportion of WPC had significant effects on BD; at higher temperatures, BD was lower. Feed moisture and pH had significant effects on EI; with lower moisture and higher pH, the EI increased. An interaction of barrel temperature and feed moisture had an effect on WAI; at lower moisture content, the temperature effect was nonexistent, whereas at higher temperatures and feed moisture content, the WAI increased. The pH level had a significant effect on WSI, showing high WSI when lower pH levels were used. Color analysis showed that higher protein content and pH generated higher δE values; low feed moisture and low pH resulted in gel syneresis. Higher in vitro digestibility was obtained when a higher WPC proportion and pH were used. Extruded WPC‐CS blends under alkaline and acidic conditions were affected by the preparation of diverse formulations that potentially can be used in foods to improve some functional and protein content.
Effect of Flour Extraction Rate on White and Red Winter Wheat Flour Compositions and Tortilla Texture
Authors: Ramírez‐Wong Benjamín , Walker C. E. , Ledesma‐Osuna Ana I. , Torres Patricia I. , Medina‐Rodríguez Concepción L. , López‐Ahumada Guadalupe A. , Salazar‐García María G. , Ortega‐Ramírez Refugio , Johnson A. M. , Flores Rolando A.
Published: June 2007

Wheat flours commercially produced at 74, 80, and 100% extraction rates made from hard white winter wheat (WWF) and hard red winter wheat (WRF) were used to produce tortillas at a commercial‐scale level. Flour characteristics for moisture, dry gluten, protein, ash, sedimentation volume, falling number, starch damage, and particle‐size distribution were obtained. Farinograms and alveograms were also obtained for flour‐water dough. A typical northern Mexican formula was used in the laboratory to test the tortilla‐making properties of the flours. Then commercial‐scale tortilla‐baking trials were run on each flour. The baked tortillas were stored at room and refrigeration temperatures for 0, 1, 2, and 3 days. Maximum stress and rollability were measured every day. Tortilla moisture, color, diameter, weight, and thickness were measured for each treatment. Finally, tortilla acceptability was tested by an untrained sensory panel. Analyses of variance (ANOVA) were performed on the data. WWF had higher protein content, dry gluten, sedimentation volume, and water absorption than the WRF. The WWF was the strongest flour based on farinograph development time and alveograph deformation work. It also produced the most extensible dough measured with the alveograph (P/L). Flour protein and ash contents, water absorption, and tenacity increased directly with the flour extraction rate. Both WWF and WRF performed well in commercial‐scale baking trials of tortillas. Tortillas made with both types of flours at 74 and 80% extraction rates had the best firmness and rollability. However, tortillas made with WWF 80% had the best color (highest L value). Tortillas prepared with 100% extraction rate flour were also well accepted by the sensory panel, had good textural characteristics, and became only slightly firm and slightly less rollable after three days of storage at room temperature.
Preparation and Properties of Oxidized Corn Starches by Semi‐Dry Process
Authors: Hou Hanxue , Dong Haizhou , Liu Guanjun , Zhang Hui
Published: June 2007

Oxidized corn starch prepared by a semi‐dry process using hydrogen peroxide as an oxidant was studied. The optimum oxidation conditions of corn starch were mole ratio of H2O2 and anhydroglucose unit (0.219); mole ratio of NaOH and anhydroglucose unit (0.144); moisture content of the reaction mixture (27.2%); and reaction temperature (65°C). Compared with oxidized corn starch produced by reacting starch with sodium hypochlorite in alkaline slurry, oxidized corn starches produced by a semi‐dry process apparently had different properties. Oxidation by a semi‐dry process for corn starch resulted in significant changes in the degree of crystallinity of starch and the changes increased with the increase of carboxyl content of starch. Peak viscosities of oxidized starches produced by a semi‐dry process were lower than those of commercial corn starch at similar carboxyl contents, while the final viscosities and setbacks of the former were much higher than the latter. There were apparent differences for texture properties among oxidized starches prepared by different processes. Onset temperature, peak temperature, and conclusion temperature of semi‐dry oxidation starches were higher than those of commercial oxidized starch, while the enthalpy of gelatinization of the former were lower than the latter.
Influence of Alkaline Formulation on Oriental Noodle Color and Texture
Authors: Hatcher D. W. , Anderson M. J.
Published: June 2007

Patent (60% yield) and straight‐grade flours of Canada Western Red Spring (CWRS) and Canada Prairie Spring White (CPSW) wheat were used to determine the influence of different ratios of alkaline salts, their concentration, and NaCl on the texture and color characteristics of the yellow alkaline noodles. Addition of 3% (w/w) salt to any formulation resulted in a significant increase in the amount of work required to process the raw noodles, while significantly lower work input was observed for noodles prepared using a 5% (w/w) 9:1 Na‐to‐K carbonate ratio without salt formula. Wheat class, extraction rate, and alkali formulation had a significant effect on raw noodle brightness with noodles prepared using 5% carbonate being brighter than the 1% carbonate noodles. Maximum cooked noodle thickness was achieved from all flours using a 1% 9:1 Na‐to‐K carbonate ratio, 3% salt formulation. The inclusion of 3% NaCl into the formula resulted in noodles significantly thicker than the corresponding salt‐free formula for all flours. Cooked noodle texture parameters evaluated were maximum cutting stress (MCS), resistance to compression (RTC), recovery (REC), and stress relaxation time. In all cases, the presence of 3% salt in the various formulations resulted in a decrease in each parameter relative to the corresponding salt‐free formulation. Desirable bite (MCS), chewiness (RTC, REC), and relaxation times were achieved with a 1% concentration of alkali salts, without NaCl, regardless of the Na‐to‐K carbonate ratio. Use of a 5% concentration of alkali salts resulted in a significant reduction in texture that was most pronounced for the 1:9 Na‐to‐K carbonate formulation.
Nitrogen and Sulfur Concentrations and Flow Rates of Corn Wet‐Milling Streams
Authors: Rausch Kent D. , Raskin Lutgarde M. , Belyea Ronald L. , Clevenger Thomas E. , Tumbleson M. E.
Published: June 2007

Nitrogen (N) and sulfur (S) concentrations can affect the market value of coproducts from corn wet‐milling. The composition of parent streams would be expected to affect composition of the resulting coproducts but there are few published data available to examine this relationship. Concentration and flow data are needed to determine which streams are important in modifying N and S coproduct concentrations. The objective was to measure concentrations and flows of N and S in corn wet‐milling streams. Samples were taken from 21 process streams from 3 wet‐milling plants during two periods of three weeks each; N and S concentrations of each sample were determined. There were large differences in N and S concentrations among processing streams; within most streams, N and S concentrations were similar among plants. Concentrations of N and S were related inversely to flow rates. Steepwater and gluten streams contained most of the N and S flow and provide an opportunity for modification. The process water stream carried large quantities of N and S and represents another opportunity for improving process efficiency and coproduct value.
Suitability of Different Starches for Production of Kuanfen (Chinese Flat Starch Noodles)
Authors: Yuan Mei‐Lan , Lu Zhan‐Hui , Cheng Yong‐Qiang , Li Li‐Te
Published: June 2007

Starches from potato, corn, sweet potato, and rice were compared with mung bean starch for their suitability for producing kuanfen, Chinese flat starch noodles. Significant differences were found in the chemical composition and swelling power among starches (P < 0.05). Maximum tensile stress and maximum tensile strain was highest for kuanfen made from mung bean starch and sweet potato starch, respectively. Higher work was needed to break kuanfen made from mung bean and sweet potato starches. Kuanfen made from mung bean starch was most favored by panelists, followed by those from sweet potato starch. General acceptability of kuanfen correlated positively and significantly with chewiness, cohesiveness, and elasticity of the noodles. For predicting sensory acceptability of kuanfen using instrumental methods, correlation was performed between sensory variables and tensile parameters. Results showed that work‐to‐break correlated significantly with chewiness, elasticity, and general acceptability while maximum tensile strain correlated significantly with sensory cohesiveness. Therefore, both of these two tensile parameters could be useful for predicting the textural properties of kuanfen.
Influence of Physical Grain Characteristics on Optimal Rotor Speed During Impact Dehulling of Oats
Authors: Doehlert Douglas C. , Wiessenborn Dennis P.
Published: June 2007

Central to commercial oat (Avena sativa L.) processing is impact dehulling. During impact dehulling, oats are fed into a spinning rotor that expels the grains against an impact ring. The impact frees the groat from the hulls. To optimize dehulling protocols, we examined the effects of physical grain characteristics and rotor speed on oat dehulling using an impact dehuller. We separated grain of three cultivars (Gem, CDC Dancer, Ronald) according to size by sieve fractionation (separation by width), disk fractionation (separation by length), and by gravity table (separation by density). Grains were characterized by mass, digital image analysis, and bulk density. Samples (50 g) were adjusted to 9% moisture and dehulled at four different rotor speeds. Groat percentage, dehulling efficiency, and groat breakage were measured after dehulling. In general, oats with higher bulk density dehulled more efficiently at slower rotor speeds, regardless of grain mass. Groat breakage increased with rotor speed and with grain mass. Adjusting dehulling conditions according to grain size improved groat yields over optimal dehulling conditions for unfractionated grains for some cultivars. More refined fractionation of grain according to bulk density may provide further improvement of groat yield during impact dehulling.
Effect of Gaseous Acetic Acid on Dough Rheological and Breadmaking Properties
Authors: Seguchi Masaharu , Hayashi Machiko , Matsumoto Hiroshi
Published: June 2007

Breads baked from wheat flours (protein contents 14.1–16.5% at 14.0% mb) that were pretreated with 2–3 mL of gaseous acetic acid per kg of wheat flour, showed maximum bread height and specific volume (cm3/g). Flour‐water suspension and the crumb pH values were gradually decreased with increased amounts of acetic acid. Gas generation and dough expansion tests with bread dough showed that the addition of the same amount of acetic acid, which achieved maximum specific volume, also showed the highest rate of gas generation and dough expansion. However, increasing acetic acid decreased these values. Scanning electron microscope (Cryo‐SEM) observation showed that the bread dough made from the same acetic acid‐treated flour indicated continuum and no cracks in the dough matrix. Evaluation of mixograms showed the decrease of mixing stability with increased acetic acid levels. Viscosity and water binding capacity of flour‐water suspensions were sharply increased by the addition of acetic acid at pH 5.0–3.5.
Molecular Modeling of the N‐terminal Regions of High Molecular Weight Glutenin Subunits 7 and 5 in Relation to Intramolecular Disulfide Bond Formation
Authors: Köhler Peter , Keck‐Gassenmeier Bettina , Wieser Herbert , Kasarda Donald D.
Published: June 2007

Analyses of cystine peptides derived from the high molecular weight glutenin subunits (HMW‐GS) 5 and 7 indicate that, in spite of a distinct sequence homology between the two subunits in the N‐terminal region, different disulfide linkages of cysteine residues are present in these regions. To investigate the structural basis for these experimental results, the conformational structures of the polypeptide chains corresponding to the N‐terminal regions (first 50 amino acids) of the wheat HMW‐GS 5 and 7 were modeled by computer methods. Secondary structures were predicted by the method of Rost and Sander (1993) and, to the extent appropriate, applied to the constructed polypeptide chains. The resulting structures were energy‐minimized and subjected to simulated heating and dynamic equilibration. In the final structure of subunit 5, the first two cysteines were located in a region of continuous α‐helix. If folding to the helical form occurs rapidly during biosynthesis as expected, the distance between the sulfhydryl groups of these two cysteines would be great enough (≈2.2 nm) to make intramolecular disulfide bond formation unlikely. Although a somewhat similar region of α‐helix was predicted for the subunit 7, in some predictions the helix was interrupted between the first two cysteines, and this break was assigned either extended structure or arbitrarily modeled as an inverse γ‐turn. In the final structure of subunit 7 with the assigned inverseγ‐turn, after energy minimization, heating, and dynamics, the two cysteines approached one another closely (≈0.4 nm). Formation of an intramolecular disulfide bond appeared a likely possibility. This model is in accord with experimental evidence for this latter intramolecular bond (Köhler et al 1993). In agreement with the modeling, an equivalent intramolecular disulfide bond of subunit 5 has not been found and experimental evidence for a different arrangement is presented.