bluuebunny/crossref_metadata_2025 huggingface dataset:
Average Shear Rates in the Rapid Visco Analyser (RVA) Mixing System
Authors: Lai K. P. , Steffe J. F. , Ng P. K. W.
Published: June 2007

The principle of mixer viscometry was utilized to determine the average shear rate in the mixing system (impeller‐cup combination) of the Rapid Visco Analyser (RVA). A relationship between the impeller Reynolds number and the power number was established with Newtonian standards. Using the matching viscosity technique and non‐Newtonian fluids consisting of various aqueous solutions of guar gum and methylcellulose, the average value of the mixer viscometer constant (k′) was 20.1/rev over speeds of 1.0–3.5 rev/sec (60–210 rpm). Hence, the average shear rate in the RVA can be estimated as 20.1 multiplied by the angular velocity given in revolutions per second. Results show the RVA system has very good potential for characterizing the rheological properties of various non‐Newtonian fluid foods.
Alkali Debranning of Sorghum and Millet
Authors: Lazaro E. L. , Favier J. F.
Published: June 2007

Aqueous solutions of sodium hydroxide were used to debran whole sorghum and millet grains. The alkali solution was effective in dissolving the pericarp, leaving the kernel free of pericarp. Various combinations of concentration of sodium hydroxide (3, 6, and 10%, w/w) and soaking duration (5, 8, and 10 min) were investigated. Two cultivars of sorghum (Dionje and Jumbo) and one cultivar of pearl millet (IM) were used in the study. A 10% aqueous solution of sodium hydroxide at 60°C was most effective in dissolving the pericarp of both sorghum and millet after 10 min of soaking, resulting in ≈90% yield of clean endosperm for all grain types. The debranning process reduced the fiber content (measured as crude fiber) of sorghum cultivars Dionje and Jumbo by 37.6 and 41.8%, respectively; and pearl millet by 32%.
Solvent Extraction of Zein from Dry‐Milled Corn
Authors: Shukla Rishi , Cheryan Munir , DeVor Richard E.
Published: June 2007

Batch extraction of zein from dry‐milled whole corn with ethanol was optimum with 70% ethanol in water, an extraction time of 30–40 min, and temperature of 50°C. High yields (60% of the zein in corn) and high zein contents in the extracted solids (50%) were obtained at a solvent‐to‐solids ratio of 8 mL of 70% ethanol/g of corn. However, zein concentration in the extract was higher at lower ratios. Multiple extraction of the same corn with fresh ethanol resulted in a yield of 85% after four extractions, whereas multiple extractions of fresh corn with the same ethanol resulted in high (15 g/L) zein concentration in the extract. Optimum conditions for batch extraction of zein were 45°C, with 68% ethanol at a solvent‐to‐solids ratio of 7.8 mL/g for an extraction time of 55 min. Column extractions were also best at 50°C and 70% ethanol; a solvent ratio of 1 mL/g resulted in high zein concentrations in the extract (17 g/L) but yields were low (20%).
Effects on Pasting Viscosity of Starch and Flour from Different Operating Conditions for the Rapid Visco Analyser
Authors: Batey Ian L. , Curtin Barbara M.
Published: June 2007

Three wheat flours, three wheat starches, a regular maize starch and a waxy maize starch were subjected to a number of different RVA profiles. Five different initial temperatures were used, 40, 50, 55, 60, and 65°C, with different initial holding times (0–3 min), heating times (2fl–10 min), holding times at 95°C (0–6 min), cooling times (2–6 min), and final hold times (0–10 min) being applied. A range of final temperatures of 30–60°C was also utilized. Significant variations in viscosity were observed with these conditions, particularly in wheat starch and flour. The most important parameters causing these variations were the initial temperature, the heating rate, and the final holding time. Short initial holding times also resulted in a wider spread of values for peak viscosity although there was little effect on the mean value and no significant effect on the holding strength or final viscosity. The final temperature was also important in that lower temperatures gave more viscous gels. Provided that the desired cooling rate could be achieved, varying the cooling time had no effect on the peak or trough viscosities and only a very minor effect on the final viscosity. If final temperatures of 40°C or lower are to be used, the cooling conditions and final hold time would need to be adjusted so that maximum viscosity could be achieved. A proposal for a standard Rapid Visco Analyser (RVA) procedure is: at least 1 min at 50°C, heat to 95°C over 4 min, hold at 95°C for 4 min, cool to 50°C in 3 min, and hold at 50°C for 4 min. These conditions should minimize variation within samples and should allow a better comparison between samples.
Effects of Gelatinization and Moisture Content of Extruded Starch Pellets on Morphology and Physical Properties of Microwave‐Expanded Products
Authors: Lee Eun Yong , Lim Kyung Il , Lim Jae‐kag , Lim Seung‐Taik
Published: June 2007

Extruded pellets were prepared from normal corn starch using a corotating twin‐screw extruder (25:1 L/D ratio, 31 mm diameter screw), and then expanded by heating in a conventional microwave oven for 70 sec. The effects of gelatinization level and moisture content of the extruded pellets on the morphology and physical properties of the microwave‐expanded products such as puffing efficiency, expansion bulk volume, and bulk density were investigated. The expanded shape and air cell structure differed according to the degree of gelatinization of the pellets. Maximum puffing efficiency and expansion volume with the pellets containing 11% moisture were achieved at 52% gelatinization. For this level of gelatinization, starch was extruded at 90°C barrel temperature. In addition, the moisture content of the pellets critically affected the expansion behavior. The maximum puffing efficiency and expansion volume were achieved in a moisture range of 10~13%. For optimum product shape and uniform air cell distribution, the pellets should undergo sudden release of the superheated vapor during the microwave‐heating. The expansion by microwave‐heating was optimized at ≈50% gelatinization.
Classification of Single‐ and Double‐Mutant Corn Endosperm Genotypes by Near‐Infrared Transmittance Spectroscopy
Authors: Campbell M. R. , Sykes J. , Glover D. V.
Published: June 2007

A total of 1,176 grain samples representing 10 different single‐ and double‐mutant genotypic classes of specialty starch corn were used for developing various classification models based on near‐infrared transmittance spectra. The genotypes used included amylose‐extender (ae), dull (du), sugary‐2 (su2), waxy (wx), ae wx, ae du, ae su2, du wx and du su2. Two‐class classification models (only two genotypes compared) were developed using partial least squares analysis (PLS) while three‐way and multiclass models were examined using principal component analysis (PCA). The effectiveness of the calibrations was evaluated by examining the percentage of unknown grain samples incorrectly classified. In general, two‐class models performed better than multiclass models. However, they did not show improvement when discriminating among genotypes with overlapping amylose contents such ae du vs. ae and ae su2 vs. ae. Three‐way models including double‐mutants and their corresponding single‐mutant counterparts had misclassification percentages typically <5% using 14 PCA factors but again, with the exception of models including genotypes with overlapping amylose contents such as ae du vs. ae vs. du. The best multiclass model using all 10 genotypic classes simultaneously revealed only two classes (ae su2 and du) with misclassification rates >10% based on 16 PCA factors. This study demonstrates that, depending on the material to be considered, near‐infrared transmittance spectroscopy could be useful when segregation of specialty starch hybrids grain from other grain types is necessary.
Effects of Nitrogen and Sulfur Fertilization on Commercial‐Scale Wheat Quality and Mixing Requirements
Authors: Wooding A. R. , Kavale S. , Wilson A. J. , Stoddard F. L.
Published: June 2007

The effect on physical dough properties of nitrogen and sulfur fertilizer applied during cultivation was observed in two trials using the bread wheat (Triticum aestivum) cultivar Otane. Wheat flours from both trials were evaluated for physical dough properties under laboratory conditions and also under industrial conditions in the second trial. The laboratory and industrial optimum mechanical dough development (MDD) work input (WI) significantly increased when nitrogen (N) fertilizer was applied without sulfur fertilizer (S) during crop cultivation. With combined N and S fertilization, laboratory and industrial WI remained close to levels for grain grown without fertilizer. Reductions in extensigraph resistance to extension (Rmax) and increases in extensigraph extensibility (Ext) due to S fertilization also were observed. None of the observed changes in WI, Rmax, or Ext due to S fertilization significantly affected end‐product quality as measured by loaf volume, crumb grain, and bake score. The nexus between WI and Rmax was weakened by combined N and S fertilization in the first trial, but remained strong in the second trial. Both WI and Rmax increased as N fertilizer and flour nitrogen increased, but at different rates. This observation indicated that by applying N fertilizer to improve dough strength, a disproportionate and disadvantageous increase in WI also resulted, which could be tempered by S fertilization. In this regard, an optimum N:S fertilizer ratio of 3:1 was indicated, although this ratio would be dependent on the balance of available N and S in the soil. Flour N:S ratios <12.5 kept WI to levels desirable in an industrial MDD bakery. Correlations between laboratory WI, mixograph development time (except in the SN1 trial), and farinograph development time were significant. The 125‐g MDD mixers appeared to be more responsive when measuring mixing requirements than the mixograph and farinograph to variations in quality due to environmental and agronomic influences and correlated better with industrial performance.
Effects of Transglutaminase Enzyme on Fundamental Rheological Properties of Sound and Bug‐Damaged Wheat Flour Doughs
Authors: Köksel H. , Sivri D. , Ng P. K. W. , Steffe J. F.
Published: June 2007

Transglutaminase (TG) catalyzes the formation of nondisulfide covalent crosslinks between peptide‐bound glutaminyl residues and ∊‐amino groups of lysine residues in proteins. Crosslinks among wheat gluten proteins by TG are of particular interest because of their high glutamine content. Depolymerization of wheat gluten proteins by proteolytic enzymes associated with bug damage causes rapid deterioration of dough properties and bread quality. The aim of the present study was to investigate the possibility of using TG to regain gluten strength adversely affected by wheat bug proteases. A heavily bug‐damaged (Eurygaster spp.) wheat flour was blended with sound cv. Augusta or cv. Sharpshooter flours. Dynamic rheological measurements, involving a frequency sweep at a fixed shear stress, were performed after 0, 30, and 60 min of incubation on doughs made from sound or blended flour samples. The complex moduli (G* values) of Augusta and Sharpshooter doughs blended with 10% bug‐damaged flour decreased significantly after 30 min of incubation. These dough samples were extremely soft and sticky and impossible to handle for testing purposes after 60 min of incubation. To test the possibility of using TG to counteract the hydrolyzing effect of bug proteases on gluten proteins, TG was added to the flour blends. The G* values of TG‐treated sound Augusta or Sharpshooter doughs increased significantly after 60 min of incubation. The G* values of the Augusta or Sharpshooter doughs blended with bug‐damaged flour increased significantly rather than decreased after 30 and 60 min of incubation when TG was included in the dough formulation. This indicates that the TG enzyme substantially rebuilds structure of dough hydrolyzed by wheat bug protease enzymes.
Changes in SDS Solubility of Glutenin Polymers During Dough Mixing and Resting
Authors: Aussenac Thierry , Carceller Jean‐Luc , Kleiber Didier
Published: June 2007

An online coupling of high‐performance size‐exclusion chromatography (HPSEC) combined with multiangle laser‐light scattering (MALLS) and a reverse‐phase HPLC procedure were used to characterize and reveal the polydispersity of the glutenin polymers of doughs during mixing and resting. Experiments involved doughs prepared from several samples of a common French wheat cultivar (Soissons) differing in total amount of SDS‐unextractable glutenin polymers. During dough mixing, the amounts, size distribution of protein, and glutenin subunit composition within the SDS‐unextractable polymers changed. However, the major changes in SDS‐unextractable glutenin content and size distribution occurred before the peak mixing time (MT) was reached, whereas detectable changes in subunit composition also occurred after the peak MT. Even if sonication, which was used to solubilize the total wheat glutenin, can narrow the glutenin size distribution, HPSEC‐MALLS revealed a close relationship between the SDS solubility of the glutenin polymers and size distribution, confirming a depolymerization and repolymerization hypothesis. During the depolymerization of the SDS‐unextractable polymers, glutenin subunits were released in nonrandom order, which indicated that the polymers have a hierarchical structure. Some HMW glutenin subunits (HMW‐GS), especially 1D×5, were particularly resistant to the depolymerization mechanism. This suggested that the subunit plays a major role in forming the backbone of the SDS‐unextractable polymers, consistent with the potential to form branched structure. These studies suggest that the SDS‐unextrac‐table polymers in flours have a well‐ordered structure that can be modified by dough mixing and resting.
Foam‐Forming Capacity of Substances Present in Rye
Authors: Meuser F. , Busch K. G. , Fuhrmeister H. , Rubach K.
Published: June 2007

Aqueous extracts of rye milling products were tested to establish foam‐forming capacity. The foams were characterized according to volume and strength. The extracts were treated chemically, thermally, and enzymatically to demonstrate the influence of the protein and of polymeric nonstarch carbohydrates on foam formation. The foam formation was attributable to a relatively homogeneous water‐soluble protein with a Mr of 12.3 kDa and an isoelectric point at pH 5.97. The other components of the extracts of rye milling products either contribute to a certain extent to stabilizing the foams derived from aqueous extracts (fructosans) or, in some cases, to destabilizing them (pentosans).
Determining Wheat Dough Mixing Characteristics from Power Consumption Profile of a Conventional Mixer
Authors: Hwang C. H. , Gunasekaran S.
Published: June 2007

A Hobart mixer with a pin‐type attachment was used to mix soft wheat flour dough. Power consumption profiles were measured continuously during mixing for 20 min using a current transducer and a data logging system. Experimental variables were quantity of flour (500, 1,000, and 1,500 g of dry wheat flour), water content (43, 45, and 47%, wb), and mixer speed setting (low, medium, and high). The power consumption profiles were evaluated by moving average and spectral analysis. Peaks in the power consumption profiles were located to determine the optimal mixing time. The optimal mixing times were then compared with storage and viscous moduli measured using a dynamic rheometer to assure the maximum strength of wheat dough at the optimal mixing time. Tolerance was determined using the signal amplitude and phase angle data from spectral analysis. Optimal mixing times of various doughs at medium speed ranged from 510 to 850 sec; low and high flour quantities required longer mixing times than medium quantity of flour. The optimal mixing time increased when the moisture content was lowered. Tolerance was affected by mixing speed and moisture content of flour
Kinetic Approach to Nixtamalization of Corn Pericarp
Authors: Martínez Ricardo , Mendoza Silvia , Reguera Edilso , Ortiz Pedro , de la Luz Martínez José
Published: June 2007

The nixtamalization of the pericarp isolated from grains of corn was studied with 2, 5, 10, 20 and 40% Ca(OH)2 based upon the mass of the pericarp. For 2 and 5% Ca(OH)2 a small loss of the mass of the pericarp takes place quickly which is accompanied by an abrupt fall of the concentration of the OH‐ ions. A suitable kinetic model for the decrease of the mass of the pericarp is a two phases exponential equation. The second phase is the slowest and it depends on the quantity of Ca(OH)2 employed.
Fine Structures of Amylose and Amylopectin from Large, Medium, and Small Waxy Barley Starch Granules
Authors: Tang H. , Ando H. , Watanabe K. , Takeda Y. , Mitsunaga T.
Published: June 2007

Amylose and amylopectin were prepared from large, medium, and small granule starches of classified waxy barley flour, and their fine structures were investigated. The amylose content had a wide distribution range (≈1.4–9.4%). Number‐average degrees of polymerization (DPn) of the amyloses were similar among the samples (≈1,200–1,300). But number of chains per molecule (NC) decreased from the surface to the center (≈6–10 chains). DPn of the amylopectins varied from 4,657 to 14,604; decreased in the order of large, medium, and small granules in same fractions of the grain; and increased from the surface layer to the center. Longest chains (LC) were not found in any of the amylopectin molecules. The large amylopectin molecule had more long chains and fewer A chains than the small molecule. The amylose content had definite effects on the transition temperature range and crystal formation of the starch granules. There were positive correlations between DPn of the amylopectin and relative crystallinity (γ = +0.69) and enthalpy value (γ = +0.80), respectively. These findings may help to elucidate biosynthesis mechanism of starch.
Degree of Milling Effects on Rice Pasting Properties
Authors: Perdon A. A. , Siebenmorgen T. J. , Mauromoustakos A. , Griffin V. K. , Johnson E. R.
Published: June 2007

The effects of degree of milling on pasting properties of medium‐grain (cv. Bengal and Orion) and long‐grain rice (cv. Cypress and Kaybonnet) were quantified using a Brabender ViscoAmylograph and a Rapid Visco Analyser. For all the cultivars tested, surface and total lipid contents decreased as the degree of milling increased. The peak viscosities for all rice increased with the degree of milling and the rates of increase were higher for medium‐grain than long‐grain cultivars. Degree of milling did not have a consistent effect on final viscosity for all the cultivars tested.
Effect of Maize Tempering on Throughput and Product Yields
Authors: Mehra S. K. , Gupta D. K. , Buriak P. , Tumbleson M. E. , Eckhoff S. R.
Published: June 2007

Scientifically researched 2‐ and 3‐stage tempering procedures and the commercially practiced 1‐stage procedure were compared for throughput and corn dry‐milling product yields at pilot‐scale (30‐kg lots) operation. The throughput and product yields were influenced by the temper procedure and the tailgate weight distance. For most corn dry‐milling products, yields corresponding to 2‐ or 3‐stage tempering procedures could be equaled or surpassed using the 1‐stage tempering procedure at specific temper durations. In general, yields from the 2‐stage and 3‐stage procedures were comparable to the yields from the 1‐stage procedure at temper durations of 30–40 and 50–60 min, respectively. An increase in the tailgate weight distance improved the product yields for temper durations <30 min but reduced the yields for longer temper durations. An increase in temper duration ≤50 min resulted in a reduction in throughput but an improvement in flaking grit yield. The temper duration and tailgate weight distance could be suitably adjusted for obtaining the desired output.
Image Analysis of Whole Grains: A Noninvasive Method to Predict Semolina Yield in Durum Wheat
Authors: Novaro P. , Colucci F. , Venora G. , D'Egidio M. G.
Published: June 2007

Durum wheat grain samples (n = 327) harvested during 1998 and 1999 in eight different Italian agroclimatic areas and representative of the main Italian cultivars were analyzed. Image analysis of whole grains allowed five size and shape descriptors (length of minor and major axes, perimeter, area, and ellipsoidal volume) to be measured on 100 grains for each sample. By multiple regression analysis, shape measures more valid to explain semolina yield were identified. By combining these measures with test weight or 1,000‐seed weight, equations useful to predict semolina yield were developed.
Effect of Steeping Treatment on Pasting and Thermal Properties of Sorghum Starches
Authors: Beta Trust , Corke Harold , Taylor John R. N. , Rooney Lloyd W.
Published: June 2007

Chemical treatments in wet milling could improve the physico‐chemical properties of starch isolated from high‐tannin sorghums. Sorghums Chirimaugute (medium‐tannin), DC‐75 (high‐tannin), and SV2 (tannin‐free) were steeped in water, dilute HCl (0.9%, v/v), formaldehyde (0.05%, v/v), and NaOH (0.3%, w/v) solutions before wet milling and starch separation. Pasting, textural, and thermal properties of starch were determined. Steeping in NaOH resulted in starches with higher peak viscosity (PV), cool paste viscosity (CPV), and setback than when water, HCl, and formaldehyde were used. The time to PV (Ptime) and PV temperature (Ptemp) were markedly reduced by treatment with NaOH. NaOH could have caused a degree of pregelatinization. HCl treatment gave starches with higher Ptemp and P time, presumably due to delayed granule swelling. Gel hardness was largely determined by the starch amylase content. The low hardness of DC‐75 starch gels was slightly improved in NaOH‐treated grains. Gelatinization temperatures of sorghum starches were generally low, regardless of steeping treatment. Starch from NaOH‐treated grain generally had slightly higher gelatinization temperatures than when water, HCl, or HCHO was used. Chemical treatments during steeping of sorghum grains greatly affected starch properties. Dilute alkali steeping during wet milling could be used to improve properties of starch isolated from tannin‐containing sorghums.
Near‐Infrared Reflectance Analysis for Prediction of Cooked Rice Texture
Authors: Champagne Elaine T. , Bett‐Garber Karen L. , Grimm Casey C. , McClung Anna M. , Moldenhauer Karen A. , Linscombe Steve , McKenzie Kent S. , Barton Franklin E.
Published: June 2007

The ability of near‐infrared (NIR) spectroscopy to predict sensory texture attributes of diverse rice cultivars was examined. The sensory texture of 87 samples representing 77 different short‐, medium‐, and long‐grain cultivars was evaluated by trained panelists using descriptive analysis. Correlations between sensory texture attributes and NIR reflectance data were examined using the multivariate method of partial least squares (PLS) regression. Texture attributes (hardness, initial starchy coating, cohesiveness of mass, slickness, and stickiness) measured by panelists in the early evaluation phases were successfully predicted (R2calibration 0.71–0.96). Cohesiveness of mass, the maximum degree to which the sample holds together in a mass while chewing, was best modeled with R2calibration = 0.96 and R2validation = 0.90. Key wavelengths contributing to the models describing the texture attributes were wavelengths also contributing to models for amylose, protein, and lipid contents.
Effects of Break‐Roll Differential on Semolina and Spaghetti Quality
Authors: Manthey Frank A. , Hareland Gary A.
Published: June 2007

Break‐roll differential provides the shearing action needed to remove bran from the endosperm. The effects of break‐roll differential on semolina and spaghetti quality were investigated using a 25‐quintal (55‐cwt/day) durum pilot‐mill system. Differentials of each break‐roll pair were adjusted to target differentials of 1.5:1, 2.5:1, and 3.5:1 by changing the velocity of the slow roll. Fast rolls were set at a velocity of 350 rpm. Bran specks, ash, and protein increased and semolina brightness (L value) and starch damage decreased with increased break‐roll differential. Semolina yellowness (b value) was greatest with 2.5:1 and least with 1.5:1 differential. Spaghetti brightness (L value) and yellowness (b value) were lower when spaghetti was made from semolina milled at 3.5:1 than from either 2.5:1 or 1.5:1 differential. Strength of dry spaghetti and spaghetti cooking loss and cooked firmness were not affected by break‐roll differential.
Resistant Starch and Total Dietary Fiber Content of Oatrim Muffins with Different Levels of Amylose, Amylopectin, and β‐Glucan
Authors: Li B. W. , Blackwell E. L. , Behall K. M. , Elmståhl H. G. M. Liljeberg
Published: June 2007

Nine types of muffins made with three levels of β‐glucan and three amylose‐amylopectin ratios were prepared at the Beltsville Human Nutrition Research Center, United States Department of Agriculture. They were fed to human subjects to study effects of starch composition and dietary fiber content on the carbohydrate and lipid metabolism in normal and overweight women. The main objective of this study was to determine resistant starch (RS) and total dietary fiber (TDF) content of the muffins 1) using AACC Approved Method 32‐07 and AOAC method 991.43, incorporating a pretreatment step with dimethyl sulfoxide (DMSO) before enzyme incubation, 2) with pretreatment at 100 and 121°C before incubation with amyloglucosidase, and 3) using samples chewed by human subjects before incubation with pancreatin and amyloglucosidase. For method 1, on an as‐eaten basis, TDF content was 2.81 to 9.64 g/100 g for samples without DMSO pretreatment and 1.66 to 4.06 g/100 g with DMSO pretreatment. RS content was 0.30 to 11.18 g/100 g for methods 1 and 2, respectively. Methods 2 and 3 had the best correlation for all muffins tested (r2 = 0.97).
Prediction of Cooked Rice Texture Using an Extrusion Test in Combination with Partial Least Squares Regression and Artificial Neural Networks
Authors: Sitakalin Chanintorn , Meullenet Jean‐Francois C.
Published: June 2007

Spectral stress strain analysis was used in combination with partial least squares (PLS) regression and artificial neural networks (ANN) to predict nine sensory texture attributes of cooked rice. The models calculated with ANN were significantly more accurate in predicting most of the sensory texture characteristics evaluated than the PLS models. Furthermore, ANN models were more robust and discriminative than PLS models.
Effects of Bran Fermentation on Quality and Microstructure of High‐Fiber Wheat Bread
Authors: Salmenkallio‐Marttila M. , Katina K. , Autio K.
Published: June 2007

We compared the effects of spontaneous fermentation of the bran fraction and fermentation with added yeast or added yeast and lactic acid bacteria (Lactobacillus brevis) on the quality of wheat bread supplemented with bran. Prefermentation of wheat bran with yeast or with yeast and lactic acid bacteria improved the loaf volume, crumb structure, and shelf life of bread supplemented with bran. The bread also had added flavor and good and homogenous crumb structure. Elasticity of the crumb was excellent. Spontaneous fermentation of the bran fraction did not have the same positive effects on bread quality. The microstructure of the breads was characterized by light microscopy. The positive effect of fermentation of bran on bread quality was evident when comparing the well‐developed protein network structure of the breads baked with fermented bran with the control bread. Prefermentation of the bran with yeast and lactic acid bacteria had the greatest effect on the structure of starch. The starch granules were more swollen and gelatinized in the breads made with prefermented bran. The pretreatments of the bran fraction had no detectable effect on the microstructure of the cell wall particles in the test breads.
Effects of Preparation Temperature on Gelation Properties and Molecular Structure of High‐Amylose Maize Starch
Authors: Vesterinen Elina , Suortti Tapani , Autio Karin
Published: June 2007

In this study, 3% aqueous high‐amylose maize starch (Hylon VII) dispersions were heated to temperatures of 140–165°C. The onset and rate of gel formation was observed using a small‐strain oscillation rheometer as a function of temperature from 90 to 25°C. The gel formation clearly began earlier in high‐amylose starch paste preheated at lower temperatures, but the rate of gelation was slower and the resulting gel was weaker in comparison with starch pastes preheated at higher temperatures. In addition, the structure of the final gels was studied using large deformation compression measurements. The most rigid gel structure on the basis of small and large deformation tests was obtained for high‐amylose starch gel preheated to 150–152°C, depending on the type of measurement. The rate of gelation was also fastest in that temperature range. High‐amylose gels heated to higher temperatures lost their rigidity. The molecular weight distribution of starch molecules was measured by size‐exclusion chromatography. Heating caused extensive degradation of amylopectin, which had a great effect on amylose gel formation and the final gel properties of high‐amylose maize starch. Micrographs of Hylon VII gels showed that phase separation of starch components visible in light microscopy occurred on heating to higher temperatures.
Rapid Methods for Milled Rice Surface Total Lipid and Free Fatty Acid Determination
Authors: Lam H. S. , Proctor A.
Published: June 2007

Total lipids and free fatty acid (FFA) determination is widely used in the food industry to assess the quality of milled rice. An improved rapid ambient temperature isopropanol (IPA) extraction method to determine milled rice surface lipid was more effective than Soxhlet solvent extraction. The improved method was probably due to better extraction of polar lipids and antioxidants by IPA. A colorimetric method to determine FFA requiring only 30 μL of sample is also described. The new technique provides results similar to those obtained using the slower, conventional acid‐base titration method. The colorimetric FFA method requires a smaller sample size, has greater precision, and is more objective. The new methods are particularly suitable for industrial use in providing rapid results for large numbers of samples.
Starch and By‐Products from a Laboratory‐Scale Barley Starch Isolation Procedure
Authors: Andersson A. A. M. , Andersson R. , Åman P.
Published: June 2007

Starch was isolated from three different barleys with normal, highamylose, or high‐amylopectin (waxy) starch. The laboratory‐scale starch isolation procedure included crushing of grains, steeping, wet milling, and sequential filtration and washing with water and alkali, respectively. Yield and content of starch, protein, and dietary fiber, including β‐glucan, were analyzed in isolated starch and in the by‐products obtained. Starch yield was 25–34%, and this fraction contained 96% starch, 0.2–0.3% protein, and 0.1% ash. Most of the remaining starch was found in the coarse material removed by filtration after wet milling, especially for the high‐amylose barley, and in the starch tailings. Microscopy studies showed that isolated starch contained mostly A‐granules and the starch tailings contained mostly B‐granules. Protein concentration was highest in the alkali‐soluble fraction (54%), whereas dietary fiber concentration was highest in the material removed by filtration after alkali treatment for the normal and waxy barleys (55%). The β‐glucan content was especially high for the waxy barley in this fraction (26%). The study thus showed that it was possible to enrich chemical constituents in the by‐products but that there were large differences between barleys. This result indicates a need for modifications in the isolation procedures for different barleys to obtain high yields of starch and different by‐products. Valuable by‐products enriched in β‐glucan or protein, for example, may render starch production more profitable.
Use of Two Endoxylanases with Different Substrate Selectivity for Understanding Arabinoxylan Functionality in Wheat Flour Breadmaking
Authors: Courtin C. M. , Gelders G. G. , Delcour J. A.
Published: June 2007

A Bacillus subtilis endoxylanase (XBS) with a strong selectivity for hydrolysis of water‐unextractable arabinoxylan (WU‐AX) and an Aspergillus aculeatus endoxylanase (XAA) with a strong selectivity for hydrolysis of water‐extractable arabinoxylan (WE‐AX) were used in straight‐dough breadmaking with two European wheat flours. Dough, fermented dough, and bread characteristics with different levels of enzyme addition were evaluated with a strong emphasis on the arabinoxylan (AX) population. The WU‐AX solubilized by XBS during breadmaking were mainly released during mixing and had higher molecular weight, in contrast to their counterparts solubilized by XAA, which were mainly released during fermentation and had lower molecular weight. This coincided with increased loaf volume with XBS and a negative to positive loaf volume response with XAA. Bread firmness and dough extract viscosity also were affected by endoxylanase addition. Results confirmed that WU‐AX are detrimental for breadmaking, while WE‐AX and solubilized AX with medium to high molecular weight have a positive impact on loaf volume.
Performance of European Artificial Neural Network (ANN) Calibrations for Moisture and Protein in Cereals Using the Danish Near‐Infrared Transmission (NIT) Network
Authors: Büchmann Nils Bo , Josefsson Henrik , Cowe Ian A.
Published: June 2007

Three problems need to be addressed in networks of Infratec Grain Analysers: 1) the networks are not interconnected, 2) the partial least squares (PLS) calibrations used so far have to be individually adjusted for bias when transferred to the slave instruments, and 3) the calibrations are not entirely stable over time. Nonlinear artificial neural network (ANN) calibrations based on a large common European data set (≈4,000 samples in the training sets and ≈1,000 samples in the stop sets) were introduced to overcome these constraints. The performance of these ANN calibrations was compared with Danish PLS models for protein and moisture in cereals during the 1998 harvest in Denmark, and subsequently with PLS models based on the same European data set. ANN models were more accurate than PLS and, unlike PLS, were linear and transferable up to 25% moisture. It is suggested that the improved performance of the ANN models is attributable to the modeling technique rather than the size and nature of the European data set. In most cases, ANN models could be applied directly and without bias adjustment to slave instruments. The ANN models were also more stable, they required fewer bias adjustments or remodeling over time compared with Danish PLS models. ANN calibrations using shared data have been adopted for commercial use in several European countries and work is in progress to develop global ANN models for determination of protein in wheat and barley.
Effect of Hybrid and Physical Properties of Individual Popcorn Kernels on Expansion Volume
Authors: Tian Y. , Buriak P. , Eckhoff S. R.
Published: June 2007

The relationships between expansion volume and physical properties of three varieties of popcorn kernels were investigated on a single kernel basis. Physical properties studied were kernel size, kernel sphericity, and kernel density. Methods of measuring densities and popped volumes of individual popcorn kernels were developed. Popcorn kernels were separated into seven kernel sizes by screening with round‐hole sieves. Thirty kernels from each of three kernel sizes (4.76 < D < 5.16, 5.56 < D < 5.95, 6.35 < D < 6.75 mm) of three popcorn varieties were individually measured for sphericity, density, and popped volume. Density and sphericity measures of popcorn kernels showed little variability. Variety, kernel sphericity, and kernel density had minor effects on expansion volume. Kernel size had no effect. There were no strong linear relationships (R2 = 0.28) among expansion volume and physical properties of the three varieties of popcorn kernels. The variety with the highest mean density and the highest mean sphericity showed a tendency of producing higher mean expansion volumes.
Genetic Diversity in Properties of Starch from Zimbabwean Sorghum Landraces
Authors: Beta Trust , Obilana A. Babatunde , Corke Harold
Published: June 2007

Starch was isolated from 95 sorghum landraces from Zimbabwe using an alkali steep and wet‐milling procedure. The physicochemical properties of sorghum starch were examined for potential use in Southern Africa. All the landraces evaluated had a normal endosperm indicated by the amylose content of the starches. Starch properties were not correlated to most of the physical grain quality traits evaluated. Grain hardness was weakly correlated to starch gel adhesiveness (r = 0.36) and amylose content (r = 0.38) (P < 0.001). The mean peak viscosity (PV) of the sorghum starches was 324 Rapid Visco Analyser units (RVU) compared with 238 RVU in a commercial corn starch sample; PV was 244–377 RVU. Some landraces had low shear‐thinning starches, implying good paste stability under hot conditions. Pasting properties were highly correlated among the sorghum starches. The starch gel hardness showed considerable variation (44–71 g) among the landraces. Gelatinization peak temperatures were 66–70°C. The thermal properties of starches were not correlated with starch swelling and pasting properties. Genotype grouping by highest and lowest values in each category would allow selection of sorghums based on a specific attribute depending on the desired end use.
Molecular and Gelatinization Properties of Rice Starches from IR24 and Sinandomeng Cultivars
Authors: Lai Vivian M. F. , Shen Mei‐Ching , Yeh An‐I , Juliano Bienvenido O. , Lii Cheng‐yi
Published: June 2007

The differences in pasting properties involving gelatinization and retrogradation of rice starches from IR24 and Sinandomeng cultivars during heating‐cooling processes were investigated using a Rapid Visco Analyser (RVA)and a dynamic rheometer. The results were discussed in relation to the molecular structure, actual amylose content (AC), and concentration of the starches. Generally, both starches possessed a comparable AC (≈11 wt%), amylose average chain length (CL), iodine absorption properties, and dynamic rheological parameters on heating to 95°C at 10 wt% and on cooling to 10°C at higher concentrations. In contrast to Sinandomeng, IR24 amylose had a greater proportion of high molecular weight species and number‐average degree of polymerization (DPn). IR24 amylopectin possessed a lower DPn and greater CL, exterior CL (ECL), and interior CL (ICL). Comparing the results of RVA analysis and dynamic rheology, the gelatinization properties and higher retrogradation tendencies of IR24 starch can be related to the structural properties and depend on starch concentration. In addition, the exponent n of starch concentration for storage moduli at 25°C (G′25 ∝ Cn) increased linearly with increasing AC.
Bread Quality Relationship with Rheological Measurements of Wheat Flour Dough
Authors: Autio K. , Flander L. , Kinnunen A. , Heinonen R.
Published: June 2007

The rheological properties of wheat doughs prepared from different flour types, water contents, and mixing times for a total of 20 dough systems were studied. The results were compared with the results of standard baking tests with the same factors. Water and flour type had a significant effect on storage modulus (G′) or phase angle measured by an oscillatory test both in the linear viscoelastic region and as a function of stress, and on compressional force measured as a function of time. The correlation of maximum force of dough in compression and G′ of dough measured within the linear viscoelastic region was r = 0.80. Correlation between the compression and oscillation test improved when all measuring points of the G′ stress curve were included (r = 0.88). The baking performance of the different doughs varied greatly; loaf volumes ranged from 2.9 to 4.7 mL/g. Although the water content of the dough correlated with the rheological measurements, the correlation of G′measured in the linear viscoelastic region or maximum force from stress‐time curve during compression was poor for bread loaf volumes. Mixing time from 4.5 to 15.5 min did not affect the rheological measurements. No correlation was observed with the maximum force of compression or G′ of dough measured in the linear viscoelastic region and baking performance. Good correlation of rheological measurements of doughs and baking performance was obtained when all the data points from force‐time curve and whole stress sweep (G′ as a function of stress) were evaluated with multivariate partial least squares regression. Correlation of all data points with loaf volume was r = 0.81 and 0.72, respectively, in compression and shear oscillation.
Molecular Modeling of Unusual Spiral Structure in Elastomeric Wheat Seed Protein
Authors: Parchment O. , Shewry P. R. , Tatham A. S. , Osguthorpe D. J.
Published: June 2007

The structure of the central repetitive domain of the high molecular weight glutenin subunits, a group of elastomeric proteins from the seeds of wheat, were modeled using structure prediction and molecular dynamics. Models were generated with spiral structures, based on repetitive β‐reverse turns, within and spanning the repeat motifs of the central domains. The models were consistent with available data from biophysical studies on the intact proteins and spectroscopic (infra‐red and nuclear magnetic resonance) studies of synthetic peptides.
Quantitative Genetic Basis of Gelatinization Temperature of Rice
Authors: Tan Yifang , Xing Yongzhong , Zhang Qifa , Sun Mei , Corke Harold
Published: June 2007

Gelatinization temperature of rice starch plays an important role in grain quality. We mapped eight loci responsible for the gelatinization parameters of rice: onset temperature (To), peak temperature (Tp), conclusion temperature (Tc) and enthalpy (ΔH) using a population of 242 recombinant inbred lines (RIL). Eight quantitative trait loci (QTL) were mapped onto the chromosome regions where starch‐synthesis related genes are located. The Wx gene (granule‐bound starch synthase [GBSS]), and the region of chromosome 11 played major roles in gelatinization trait determination; and other loci were starch‐branching enzyme (SBE) genes that modify the two major loci by epistasis. High‐level interactions were also detected indicating a trans mode of action of the genes. The genetic basis for these parameters was consistent with the relationship between the thermal properties and the structure of the starch granule. This information can be helpful for the improvement of starch‐producing crops, including the improvement of rice grain quality, both for food and industrial uses.
Influence of Amylose Content on Properties of Wheat Starch and Breadmaking Quality of Starch and Gluten Blends
Authors: Lee Mee‐Ryung , Swanson Barry G. , Baik Byung‐Kee
Published: June 2007

The effects of amylose content on thermal properties of starches, dough rheology, and bread staling were investigated using starch of waxy and regular wheat genotypes. As the amylose content of starch blends decreased from 24 to 0%, the gelatinization enthalpy increased from 10.5 to 15.3 J/g and retrogradation enthalpy after 96 hr of storage at 4°C decreased from 2.2 to 0 J/g. Mixograph water absorption of starch and gluten blends increased as the amylose content decreased. Generally, lower rheofermentometer dough height, higher gas production, and a lower gas retention coefficient were observed in starch and gluten blends with 12 or 18% amylose content compared with the regular starch and gluten blend. Bread baked from starch and gluten blends exhibited a more porous crumb structure with increased loaf volume as amylose content in the starch decreased. Bread from starch and gluten blends with amylose content of 19.2–21.6% exhibited similar crumb structure to that of bread with regular wheat starch which contained 24% amylose. Crumb moisture content was similar at 5 hr after baking but higher in bread with waxy starch than in bread without waxy starch after seven days of storage at 4°C. Bread with 10% waxy wheat starch exhibited lower crumb hardness values compared with bread without waxy wheat starch. Higher retrogradation enthalpy values were observed in breads containing waxy wheat starch (4.56 J/g at 18% amylose and 5.43 J/g at 12% amylose) compared with breads containing regular wheat starch (3.82 J/g at 24% amylose).
Separation and Quantification of HMW Glutenin Subunits by Capillary Electrophoresis
Authors: Zhu J. , Khan K.
Published: June 2007

The use of capillary electrophoresis in SDS (SDS‐CE) for separation and quantification of HMW glutenin subunits (HMW‐GS) was investigated. HMW‐GS were precipitated with 40% acetone from 50% 1‐propanol extract of flour under reducing conditions after removal of monomeric proteins with 50% 1‐propanol. Poly (ethylene oxide) was used in the running buffer (3% w/v) for SDS‐CE. The results indicated that HMW‐GS could be well separated by SDS‐CE, including subunits 7+8, 7+9, 2+12, 5+10, and 17+18. However, HMW‐GS showed delayed migration times compared with molecular weight protein standards. Some HMW‐GS were reversed in their mobilities in SDS‐CE compared with their mobility and molecular weights by SDS‐PAGE. Therefore, the SDS‐CE was unsuitable for MW determination of HMW‐GS. A linear response was obtained from SDS‐CE of a plot of the concentration of HMW‐GS of the 40% acetone precipitate versus corrected areas for absorbance at 214 nm. Quantification of HMW‐GS for the two biotypes (subunits 5+10 vs. 2+12) of an Australian wheat cultivar Warigal confirmed the differences between the two biotypes in their quantity of HMW‐GS. Therefore, the technique could be used to quantify HMW‐GS in conjunction with SDS‐PAGE.
Two‐Dimensional Vibration Spectroscopy of Rice Quality and Cooking
Authors: Barton F. E. , Himmelsbach D. S. , McClung A. M. , Champagne E. L.
Published: June 2007

Rice samples were taken from a study of rice milling properties that affect quality. The spectra of milled and cooked samples were taken in the near‐infrared, mid‐infrared, and Raman region. These spectra, two regions at a time, were regressed by a two‐dimensional technique to develop contour maps that indicated the correlation of two spectral regions. These relationships demonstrate that it is possible to recognize the hydration effects caused by gelatinization (cooked samples vs. milled rice). Three water (O‐H stretch) spectral bands (960, 1445, 1,930 nm) in the near‐infrared (NIR) show marked differences between milled and cooked rice. The difference spectra indicated that there were additional phenomena occurring besides the addition of water. These differences are apparent in both C‐O‐H and N‐H bands, which indicate that water is interacting with both starch and protein. The two‐dimensional technique developed in this laboratory was used to get a better interpretation of what occurs during cooking. The Raman spectrum, which is relatively insensitive to water (O‐H stretch), revealed only changes in protein that could be associated with denaturization.