bluuebunny/crossref_metadata_2025_split huggingface dataset:
Starch Retrogradation in Cooked Pasta and Rice
Authors: Riva M. , Fessas D. , Schiraldi A. 
Published: June 2007

ABSTRACTEffect of cooking time on starch retrogradation and water distribution was studied in pasta (spaghetti) and rice (parboiled and arborio) using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) Optimum cooking times (OCT) were 8, 16, and 18.5 min for spaghetti, parboiled, and arborio rice, respectively. Swelling was observed by image analysis. OCT spaghetti and rice showed various starch retrogradation rates at various aging times and temperatures. Based on the classical Avrami function, the retrogradation rate at 5°C followed the order spaghetti > parboiled rice > arborio rice, while extent was in the opposite order. At higher temperature (20°C), the rates decreased by 20× in all cases. Thermogravimetric analysis (TGA) investigations were undertaken to check the distribution of water within these products and its relationship to starch retrogradation. During heating, water was released in two distinguishable steps at ≈80 and 100°C. Results supported the conclusion that the more tightly bound water might not participate or facilitate starch retrogradation. In this study, the overall water content did not change during storage, and water appeared to migrate from sites of stronger binding to sites of weaker binding. The temperature dependence of the Avrami constant was described with the Vogel‐Tamman‐Fulcher empirical expression.
Effect of Morphology of Mechanically Developed Wheat Flour and Water on Starch from Gluten Separation Using Cold Ethanol Displacement
Authors: Robertson G. H. , Cao T. K. , Wood D. F. 
Published: June 2007

ABSTRACTThe mechanical development of wheat flour and water creates micro and macro structures in dough or batter that critically influence the ability to separate starch from protein by fluid displacement. This study sought to identify specific structural and rheological features and to relate these to separation as indexed by the separation factor. Structural features, especially protein and starch distributions, were examined using visible light microscopy applied to dough samples that had been exposed to a protein dye. Flour and water samples were developed in a Brabender microfarinograph at conditions (water content and time of development) generally suitable for use of the USDA Western Regional Research Center, cold‐ethanol fluid‐displacement method. No truly homogenous structures were observed. However, distinct segregation of protein and starch were apparent at all conditions. Structural features correlated qualitatively with the success of separation indexed by the overall separation factor (αp/s) for the separation process. Highly segregated states characterized by large protein bands, clustered starch, and large open spaces were obtained with intermediate development (25 ± 5 min) and were most readily separated (αp/s = 118 ± 7). Segregated states with relatively thin protein bands (≤10 μm dia) in complex networks entrapping starch were obtained after additional development (≥45 min) and were less completely separable (αp/s = 32 ± 2). Segregated states with irregularly organized protein in the form of clumps and bands were obtained with minimal development and were partially separable (αp/s = 65 ± 4). Consistency indicated on the microfarinograph increases monotonically throughout and beyond the period of maximum separability. However, elasticity changes and a high rate of increase in consistency evident in the microfarinogram may reflect changes in the structure that also reduce separability. The study demonstrated the use of the ethanol method to isolate development from displacement phenomena forindependent study.
Rapid Gas Chromatographic Technique for Quantifying 2‐Acetyl‐1‐Pyrroline and Hexanal in Rice (Oryza sativa, L.)
Authors: Bergman C. J. , Delgado J. T. , Bryant R. , Grimm C. , Cadwallader K. R. , Webb B. D. 
Published: June 2007

ABSTRACTThe aroma of rice plays a role in its consumer acceptability. The popcorn‐like smell of aromatic rice stemming primarily from its 2‐ acetyl‐1‐pyrroline (2‐AP) content is considered desirable by many consumers. Conversely, hexanal has been correlated with off odors in rice that develop from lipid oxidation. A rapid method for 2‐AP and hexanal quantification suitable for use in breeding programs, large‐scale research efforts, and quality assurance programs is needed. While developing such a method, sample preparation (degree of milling, particle size), solvent extraction time and temperature, and gas chromatographic parameters were studied. Particle size had no influence on 2‐AP or hexanal recovered. One extraction solubilized ≈80% of the 2‐AP and 56% of the hexanal present in milled rice. The optimum extraction method was assessed to require 0.3 g of ground brown or milled rice in methylene chloride held at 85°C for 2.5 hr. The complete gas chromatographic run requires ≈25 min, and 50 samples can be analyzed per day. The optimized method's linear response (R2 = 0.99) and reproducibility was demonstrated. The stability of 2‐AP and hexanal in frozen milled rice and in refrigerated methylene chloride extracts was excellent for at least six months. Milled and unmilled commercial and breeders' aromatic rice samples contained 10–1,104 ng/g of 2‐AP and 148–2,541 ng/g of hexanal. Genotype had the greatest effect on the 2‐AP and hexanal content of two lines grown over four years and in four states.
Effects of Leavening Acids and Dough Temperature in Wheat Flour Tortillas
Authors: Cepeda Minerva , Waniska Ralph D. , Rooney Lloyd W. , Bejosano Feliciano P. 
Published: June 2007

ABSTRACTFunctionality of four leavening acids (sodium aluminum phosphate [SALP], sodium aluminum sulfate [SAS], monocalcium phosphate [MCP] and sodium acid pyrophosphate [SAPP‐28]) was evaluated during processing of wheat flour tortillas. Formulas were optimized to yield opaque, large‐diameter tortillas with pH 5.9–6.1. Each leavening acid and sodium bicarbonate was first evaluated at 38°C and then evaluated in combination with fumaric acid at 34 and 38°C. Ionic and pH interactions of leavening salts adversely affected dough properties and resting time. Opacity and pH of tortillas prepared with MCP was lower than for other treatments. Higher dough temperature required more leavening acid and base to compensate for some of the loss of CO2 incurred during dough mixing and resting at 38°C. The addition of fumaric acid decreased the amount of leavening acid, the dough‐resting time and tortilla pH, and improved storage stability. Combinations of MCP, SALP (or SAS), and fumaric acid produced dough and tortillas with good qualities. Tortillas prepared using SALP (or SAS) and fumaric acid tended to be of better quality.
Prediction of Cooked Rice Texture Using Extrusion and Compression Tests in Conjunction with Spectral Stress Strain Analysis
Authors: Sitakalin Chanintorn , Meullenet Jean‐Francois C. 
Published: June 2007

ABSTRACTSensory texture attributes of cooked rice from two cultivars (Bengal and Cypress) harvested in 1997 (56 samples) were predicted using extrusion and compression tests along with spectral stress strain analysis. Predictive models for each of nine sensory texture attributes studied were evaluated using force values from the instrumental tests in conjunction with partial least squares regression. All sensory attributes were well predicted using both the extrusion and compression tests (relative ability of prediction > 0.70). However, the extrusion test consistently provided more accurate and discriminative predicted models (root mean square error of prediction < 0.55, Stot/RMSEP > 2.0). Spectral stress strain analysis predictive models for adhesiveness to lips and hardness were explained.
Instrumental Assessment of Cooked Rice Texture Characteristics: A Method for Breeders
Authors: Meullenet Jean‐Francois , Champagne Elaine T. , Bett Karen L. , McClung Anna M. , Kauffmann Domitille 
Published: June 2007

ABSTRACTSensory textural characteristics of cooked rice (61 samples) were predicted using a miniature extrusion cell and the novel data analysis method Spectral Stress Strain Analysis (SSSA). Thirteen sensory texture characteristics evaluated using a trained descriptive panel and stress values from an extrusion test were used in combination with partial least squares regression to evaluate predictive models for each of the sensory attributes studied. Among the textural attributes evaluated by the panel, four (stickiness, hardness, cohesiveness of mass, and uniformity of bite [relative ability of prediction values (RAP) > 0.6, n = 61]) could be satisfactorily predicted using an instrumental test and subsequent SSSA. The quality of the models determined varied for the two grain types evaluated. This instrumental method provides a valuable screening tool for rice breeders.
Reducing Steep Time by Adding Lactic Acid During Countercurrent Steeping of Corn with Different Initial Moisture Contents
Authors: Yang P. , Eckhoff S. R. 
Published: June 2007

ABSTRACTReducing corn steep time by adding lactic acid instead of relying on in situ fermentation was studied. Corn at two initial moisture levels (15 and 20%) was steeped for 18 hr in a countercurrent steep system. The initial SO2 target concentration in steepwater was 2,000 or 3,000 ppm, while the initial lactic acid concentration in steepwater was 0, 0.28, or 0.55%. Adding lactic acid under all steeping conditions decreased steepwater pH, accelerated SO2 absorption, and increased the amount of solids released from corn. Adding lactic acid during steeping also increased the first grind slurry density and made germ skimming easier than when no lactic acid was added. Starch yields for the hybrid used in this study under all steep conditions were comparable to those from 24‐hr steeping, except when steeping corn with an initial moisture content of 15% in ≈2,000 ppm of SO2 alone. For the 20% moisture corn, adding lactic acid to fresh steepwater significantly improved the starch yield at ≈2,000 ppm of SO2 for 18‐hr steeping. At ≈3,000 ppm of SO2, adding lactic acid did not increase the starch yield for the hybrid used. The protein content in starch was significantly lower when lactic acid was added. Pasting properties of starch were not affected by adding lactic acid. The hybrid used in this study had an initial moisture content of 20% and could be wet‐milled without affecting starch yield, starch protein content, and pasting properties.
Evaluation of Compatibility of Rice Starch and Pectins by Glass Transition and Sub‐Tg Endotherms and the Effect of Compatibility on Gel Viscosity and Water Loss
Authors: Lai Yu‐Chi , Sung Po‐Hou , Chien John T. 
Published: June 2007

ABSTRACTDifferences in molecular structure and hydrophilicity may affect the compatibility of food components in a highly concentrated solution. Mixtures of TNuS19 rice starch (RS) and pectins with three different degrees of esterification (22, 64, and 92%) were used as a model system to evaluate the components' compatibility in a low‐moisture system. When analyzed individually by differential scanning calorimetry (DSC), RS, low methoxyl pectin (LMP), intermediate methoxyl pectin (IMP), and high methoxyl pectin (HMP) showed the presence of a glass transition temperature (Tg) at 75.2, 96.2, 96.4, and 93.5°C, respectively. Among mixtures, the compatible RS‐HMP exhibited only a single Tg between the Tg values of the two components, whereas the incompatible RS‐LMP showed two Tg values that were close to those of the individual components. The sub‐Tg endotherms of all three mixtures (1:1) were lower than the means of the corresponding components. The degree of decrease was more pronounced in the RS‐HMP mixture than in the others. The above results imply that the interaction, which led to close contact between side chains of the two components, was more intense in the compatible RS‐HMP mixture than in the RS‐IMP and RS‐LMP mixtures. The decrease of the sub‐Tg endotherm can be used as an index to evaluate the degree of compatibility as well as the interaction occurring between the two molecules. The above findings were further verified by dynamic mechanical analyses. Both viscosity and water retention of the compatible RS‐HMP mixed gel were significantly higher than those of the RS‐IMP and RS‐LMP mixed gels. This evidence further suggests that RS and HMP are compatible and exhibit a strong intermolecular interaction that increases gel viscosity and decreases water loss during high‐temperature heating.
NIR Transmittance Estimation of Free Lipid Content and Its Glycolipid and Digalactosyldiglyceride Contents Using Wheat Flour Lipid Extracts
Authors: Ohm J. B. , Chung O. K. 
Published: June 2007

ABSTRACTFree lipids (FL) in 72 hard winter wheat flours were extracted and dissolved in hexane. Absorbance (log 1/T) values were measured using a scanning spectrophotometer with a 2‐mm cuvette, and used to develop calibration models for estimating flour FL content and glycolipid (GL) and digalactosyldiglyceride (DGDG) contents. Fifty‐one calibration samples were selected based on the cutoff point of 0.3 of Mahalanobis distance, and the remaining twenty‐one samples were used for validation. The best model for the estimation of FL content showed coefficients of determination (R2) of 0.95 for the calibration set and R2 = 0.89 for the validation set. Glycolipid contents could be estimated by a model which had R2 = 0.87 for the calibration set and R2 = 0.89 for the validation set. For DGDG, the best model showed R2 = 0.94 for the calibration set and R2 = 0.88 for the validation set.
In Vitro Polymerization of Wheat Glutenin Subunits with Inorganic Oxidizing Agents. II. Stepwise Oxidation of Low Molecular Weight Glutenin Subunits and a Mixture of High and Low Molecular Weight Glutenin Subunits
Authors: Veraverbeke Wim S. , Larroque Oscar R. , Békés Frank , Delcour Jan A. 
Published: June 2007

ABSTRACTHigh and low molecular weight glutenin subunits (HMW‐GS and LMW‐GS) were isolated from wheat flour. LMW‐GS and a 1:2 (w/w) mixture of HMW‐GS and LMW‐GS were polymerized in vitro at pH 3.0 by stepwise oxidation with different oxidants (KBrO3, KIO3, H2O2). In analogy with the oxidation of HMW‐GS, KBrO3 produced smaller polymers for LMW‐GS than KIO3 or H2O2. While similar average sizes were found with flow‐field flow fractionation for LMW‐GS polymerized with KIO3 and H2O2, multilayer SDS‐PAGE and size exclusion HPLC indicated that size distributions were different. Significantly fewer monomers remained after polymerization of LMW‐GS than with HMW‐GS. The higher polymerization efficiency of LMW‐GS was also obvious during polymerization of a mixture of HMW‐GS and LMW‐GS. Mixed polymerization of HMW‐GS and LMW‐GS had no observable effect on the polymer size. Multilayer SDS‐PAGE of remaining monomers during polymerization revealed differences in polymerizing efficiency between structurally different glutenin subunits, with x‐type HMW‐GS and B‐LMW‐GS showing higher degrees of incorporation than y‐type HMW‐GS and C‐LMW‐GS, respectively.
Effect of Partial Gelatinization and Lipid Addition on α‐Amylolysis of Barley Starch Granules
Authors: Lauro M. , Poutanen K. , Forssell P. 
Published: June 2007

ABSTRACTThe effect of partial gelatinization with and without lipid addition on the granular structure and on α‐amylolysis of large barley starch granules was studied. The extent of hydrolysis was monitored by measuring the amount of soluble carbohydrates and the amount of total and free amylose and lipids in the insoluble residue. Similarly to the α‐amylolysis of native large barley starch granules, lipid‐complexed amylose (LAM) appeared to be more resistant than free amylose and amylopectin. Partial gelatinization changed the hydrolysis pattern of large barley starch granules; the pinholes typical of α‐amylase‐treated large barley starch granules could not be seen. Lipid addition during partial gelatinization decreased the formation of soluble carbohydrates during α‐amylolysis. Also free amylose remained in the granule residues and mostly amylopectin hydrolyzed into soluble carbohydrates. These findings indicate that lysophospholipid (LPL) complexation with amylose occurred either during pretreatment or after hydrolysis, and free amylose was now part of otherwise complexed molecules instead of being separate molecules. Partial gelatinization caused the granules to swell somewhat less during heating 2% starch‐water suspensions up to 90°C, and lipid addition prevented the swelling completely. α‐Amylolysis changed the microstructure of heated suspensions. No typical twisting of the granules was seen, although the extent of swelling appeared to be similar to the reference starch. The granules with added LPL were partly fragmented after hydrolysis.
Rice Quality by Spectroscopic Analysis: Precision of Three Spectral Regions
Authors: Barton F. E. , Himmelsbach D. S. , McClung A. M. , Champagne E. T. 
Published: June 2007

ABSTRACTThree types of spectroscopy were used to examine rice quality: near infrared (NIR), Raman, and proton nuclear magnetic resonance (1H NMR). Samples from 96 rice cultivars were tested. Protein, amylose, transparency, alkali spreading values, whiteness, and degree of milling were measured by standard techniques and the values were regressed against NIR and Raman spectra data. The NMR spectra were used for a qualitative or semiquantitative assessment of the amylose/amylopectin ratio by determining the 1–4 to 1–6 ratio for glucans. Protein can be measured by almost any instrument in any configuration because of the strong relationship between the spectral response and the precision of the reference method. Amylose has an equally strong relationship to the vibrational spectra, but its determination by any reference method is far less precise, resulting in a 10× increase in the standard error of cross‐validation (SECv) or standard error of performance (SEP) with R
2 values equal to that of the protein measurement.
Lipidemic Response of Hamsters to Rice Bran, Uncooked or Processed White and Brown Rice, and Processed Corn Starch
Authors: Kahlon T. S. , Chow F. I. 
Published: June 2007

ABSTRACTThis study was undertaken to evaluate the lipidemic response of rice bran and the possible enhancement of its healthful properties by using raw or processed white or brown rice in place of corn starch. All diets contained 10% total dietary fiber, 15% fat, and 0.5% cholesterol. Weanling male golden Syrian hamsters were fed cellulose control (CC), processed corn starch (PCS), cellulose with processed brown rice (CPBR), rice bran (RB), RB with white rice (RBWR), RB with processed white rice (RBPWR), RB with brown rice (RBBR), and RB with processed brown rice (RBPBR) diets. After three weeks, the PCS diet significantly lowered total plasma cholesterol (TC) compared with the CC, CPBR, RBWR, and RBPBR diets. RB and RBBR diets significantly lowered TC and LDL‐C compared with CPBR diet. All the RB‐containing and PCS diets significantly lowered liver cholesterol and liver lipid content. Processing white rice increased TDF content 240% and insoluble dietary fiber (IDF) 360%, whereas soluble dietary fiber (SDF) decreased by 25%. Uncooked brown rice contained 7 times as much TDF as uncooked white rice. Processing brown rice decreased its TDF, IDF and SDF contents by 12, 6, and 42%, respectively. The data suggest that a possible mechanism for cholesterol‐lowering by rice bran, with or without added raw or processed rice (white or brown), is by decreasing lipid digestibility and increasing neutral sterol excretion, whereas cholesterol‐lowering by processed corn starch is mediated through other mechanisms.
Effects of Temperature, Sonication Time, and Power Settings on Size Distribution and Extractability of Total Wheat Flour Proteins as Determined by Size‐Exclusion High‐Performance Liquid Chromatography
Authors: Morel M.‐H. , Dehlon P. , Autran J. C. , Leygue J. P. , Bar‐L'Helgouac'h C. 
Published: June 2007

ABSTRACTThe size‐exclusion (SE) HPLC profile of total protein extract obtained by sonication of flour samples at ambient temperature showed marked instability on reinjection. Instability was related to the presence of flour proteases that were inactivated by thermal treatment of flour samples at 60°C. Extraction of flour protein by sonication was a function of ultrasonic energy (sonication time × power product) delivered to flour sample. As protein solubility increased, the proportions of the earliest eluted SE‐HPLC fractions (F1 and F2) increased. Oversonication of proteins evidenced by a decrease in F1 amount at the benefit of F2 occurred below the sonication energy level needed for total protein extraction. Ultrasonic energy level was adjusted to allow total protein extraction while limiting oversonication. The sonication procedure was applied on 27 flour samples of contrasting dough strength to extract total proteins. Absolute amount of protein extractable by sonication, determined from SE‐HPLC area, was strongly correlated with flour protein content. Very significant and equivalent relationships were found between alveographic W index and absolute amount of either unextractable protein extract or F1 of SE‐HPLC profile from total protein extract.
Effects of Incorporated Glutenins on Functional Properties of Wheat Dough
Authors: Uthayakumaran S. , Stoddard F. L. , Gras P. W. , Bekes F. 
Published: June 2007

ABSTRACTThe development of reduction‐oxidation methods to open the native gluten polymer, incorporate monomers, and repolymerize the modified polymer, has allowed new types of investigation of the effects of glutenin subunits on dough characters. These methods were used to incorporate bulk high molecular weight glutenin subunits (HMW‐GS) and bulk low molecular weight glutenin subunits (LMW‐GS) from four cultivars into the parent flours to modify the HMW‐GS‐to‐LMW‐GS ratio. In addition, the glutenins from the four cultivars were added to a single base flour of differing glutenin subunit composition. Finally, HMW‐GS 7, 8, 5, and 10 were incorporated singly and in pairs into two base flours. The mixing time, peak resistance, maximum resistance to extension, and loaf height increased with increases in HMW‐GS‐to‐LMW‐GS ratio. There was a decrease in resistance breakdown observed with increase in HMW‐GS‐to‐LMW‐GS ratio. The maximum resistance to extension slightly increased with increases in HMW‐GS‐to‐LMW‐GS ratio (strongly in cultivar Hartog). Dough extensibility decreased with increase in HMW‐GS‐to‐LMW‐GS ratio (except in Osprey derivative). In the incorporation studies of single and paired glutenin subunits, HMW‐GS 5+10 gave a synergistic effect increasing mixing time, maximum resistance to extension, and loaf height as compared with HMW‐GS 5 or 10 separately. In contrast, HMW‐GS 7+8 showed an additive effect and HMW‐GS 7 incorporated separately had a higher mixing time, maximum resistance to extension, and loaf height than those of HMWGS 7+8 and HMW‐GS 8.
Physical Properties of Poly(Lactic Acid) and Starch Composites with Various Blending Ratios
Authors: Ke Tianyi , Sun Xiuzhi 
Published: June 2007

ABSTRACTTwo‐phase polymer blends of poly(lactic acid) (PLA) and corn or wheat starches at various ratios were prepared by using a laboratory‐scale twin‐screw extruder and compression molding. The blends were characterized for thermal transitions, mechanical properties, and water absorption. Starch and PLA were immiscible polymers, and the thermal behavior of PLA was not affected by starch. Crystallinity of the blends decreased in some degree as starch content increased 20–40%. Tensile strength and elongation of the blends decreased as starch content increased, but modulus increased as starch content increased up to 70%. As starch content increased to >60%, the PLA phase became discontinuous, and water absorption of the blends increased sharply. Blends made from wheat starch gave slightly better mechanical properties than those made from corn starch, and no differences in other properties were observed.