bluuebunny/crossref_metadata_2025_split huggingface dataset:
Purification and Analysis of Wheat Grain Polyphenol Oxidase (PPO) Protein
Authors: Anderson James V. , Morris Craig F. 
Published: June 2007

ABSTRACTWheat (Triticum aestivum L.) breeding programs have used various whole kernel assays to estimate polyphenol oxidase (PPO) activity, thereby identifying germplasm that has a greater chance of producing consumer products with superior color. However, the enzymes involved in these assays are poorly understood and the purification and characterization of a wheat kernel PPO protein has not been reported previously. A PPO from wheat bran was purified using ammonium sulfate precipitation, ion and size‐exclusion chromatography, and continuous elution electrophoresis. The purified protein migrated at 67 kDa on SDS‐PAGE under denaturing and reducing conditions, exhibited PPO activity in the presence of SDS, and eluted at 45 kDa on SDS‐PAGE under nondenaturing and nonreducing conditions. N‐terminal sequence analysis of peptide fragments obtained from tryptic digests confirmed the purified wheat bran protein as a PPO. This wheat PPO protein showed the greatest sequence identity to grape (Vitis vinifera) and pineapple (Ananas comosus) PPO. The purified wheat PPO shares no more sequence identity with the deduced amino acid sequence of a previously isolated partial wheat PPO sequence than it does to PPO from other plant taxa widely divergent from wheat. Based on immunoblot analysis, purified PPO from wheat bran appears to be a processed, mature form lacking an estimated 14–16 kDa transit peptide required for plastid localization.
Influence of High‐Temperature Drying on Structural and Textural Properties of Durum Wheat Pasta
Authors: Zweifel C. , Handschin S. , Escher F. , Conde‐Petit B. 
Published: June 2007

ABSTRACTStarch and protein are the main polymeric ingredients of pasta and they determine the structural and textural properties of cooked pasta. The present investigation sought better understanding of the impact of high‐temperature (HT) drying on the starch and the protein fraction, and their role in structure and texture of pasta. Durum wheat spaghetti was prepared in a pilot‐plant installation. The drying conditions were selected for the HT phase at 80 or 100°C applied at high, intermediate, or low product moisture content. Spaghetti dried at 55°C served as a reference sample. The color of dry pasta was measured and the changes in the starch and protein fractions were determined by protein solubility, light microscopy, confocal scanning laser microscopy (CSLM), cooking tests, and texture measurements. HT drying at 100°C and low product moisture promoted browning of pasta. At the molecular level, HT drying promoted protein denaturation. At the microscopic level, HT drying contributed to a better preservation of the protein network and reduced swelling of starch and disintegration of granules. At the macroscopic level, HT drying enhanced the firmness of cooked pasta and reduced surface stickiness. In general, the changes were more pronounced by increasing the drying temperature from 80 to 100°C and by shifting the HT phase from an early to a late stage of the drying process. The drying conditions are determinant for the phase morphology of protein and starch in cooked pasta which, in turn, govern the textural properties of pasta.
Amyloplast Formation and Starch Granule Development in Hard Red Winter Wheat
Authors: Bechtel Donald B. , Wilson Jeff D. 
Published: June 2007

ABSTRACTPlastids in the coenocytic endosperm of young wheat caryopses were mostly in the form of pleomorphic proplastids with a few of the plastids containing small starch granules. Following cellularization of the coenocytic cytoplasm, the outer one or two endosperm cell layers became meristematic and continued to divide until about 14 days after flowering (DAF). During the first week of endosperm development, newly divided cells had plastids that were pleomorphic in shape, while subaleurone cells interior to the meristematic region contained amyloplasts that contained a single‐size class of starch granules (incipient A‐type starch granules). The pleomorphic plastids exhibited tubular protrusions that extended a considerable distance through the cytoplasm. Amyloplasts in cells interior to the meristematic region did not exhibit protrusions. Both subaleurone and central endosperm cells had amyloplasts that exhibited protrusions at 10–12 DAF, and some of the protrusions contained small starch granules (incipient B‐type starch granules). Protrusions were not observed in endosperm amyloplasts at 14 DAF. Two sizes of starch, large A‐type and smaller B‐type granules were present within the cells, however. Amyloplast protrusions were numerous again at 17 DAF in both subaleurone and central endosperm cells; at 21 DAF, a third size class of small C‐type starch granules was observed in the cytoplasm. Amyloplasts in the endosperm of wheat apparently divided and increased in number through protrusions because binary fission typical of plastid division was never observed. Protrusions were observed in the coenocytic cytoplasm, in dividing cells, in subaleurone and central endosperm cells at 10–12 DAF, and in subaleurone and central endosperm cells at 17 DAF. The results suggest that there are three sizes of starch granules produced at specific times during wheat endosperm development.
Starch Characteristics of the Rice Mutant du2‐2 Taichung 65 Highly Affected by Environmental Temperatures During Seed Development
Authors: Suzuki Yasuhiro , Sano Yoshio , Ishikawa Tetsuya , Sasaki Tomoko , Matsukura Ushio , Hirano Hiro‐Yuki 
Published: June 2007

ABSTRACTThe effects of environmental temperature (21 vs. 28°C) during rice seed development on the starch characteristics (apparent amylose content, amylopectin chain length distribution, and gelatinization properties) of nonwaxy Taichung 65 (T65), waxy Taichung (T65wx), du2‐2 mutated low‐amylose strain Taichung (76‐3/T65), and Koshihikari were studied. Amylose contents increased with decreasing environmental temperatures. Analysis of the amylopectin chain length distribution showed that the relative amounts of long chains with degree of polymerization (DP) > 25 in all starches decreased if maturation occurred at 21°C. Gelatinization onset, peak, and conclusion temperatures and enthalpies decreased with decreasing environmental temperatures. Of all starches studied, the du2‐2 mutated low‐amylose Taichung (76‐3/T65) was most affected by maturation temperatures. These results indicate that the du2‐2 mutated low‐amylose Taichung (76‐3/T65) may be a useful strain in understanding biochemical and genetic starch biosynthesis response to slight changes in temperature.
Effects of Nitrogen Fertilizer on Protein Quantity and Gluten Strength Parameters in Durum Wheat (Triticum turgidum L. var. durum) Cultivars of Variable Gluten Strength
Authors: Ames N. P. , Clarke J. M. , Dexter J. E. , Woods S. M. , Selles F. , Marchylo B. 
Published: June 2007

ABSTRACTField studies were conducted over three years at two locations in Saskatchewan, Canada, to determine the effect of nitrogen fertilizer on protein quantity and protein strength in 10 cultivars of durum wheat (Triticum turgidum L. var. durum) representing a range of gluten strength. Increasing nitrogen fertilizer resulted in increased protein content in all cultivars across environments. Cultivars were clearly differentiated on the basis of gluten strength using a gluten index (GI), SDS sedimentation (SDSS), alveograph indices of overpressure (P) and deformation energy (W), mixograph energy to peak (ETP), and mixograph bandwidth energy (BWE) at all fertilizer levels. Variable cultivar response to nitrogen fertilizer was observed only for protein content, GI, and alveograph W. The nature of the cultivar‐by‐fertilizer interaction for GI suggested that the conventional strength cultivars would benefit more from nitrogen fertilizer than the extra‐strong types, which showed no change or slight decreases in GI with nitrogen fertilizer despite an increase in total gluten. SDSS increased with nitrogen fertilizer, following similar trends as protein. Gluten strength rankings of the cultivars by SDSS were maintained with increased fertilizer. Fertilizer had little effect on alveograph P, mixograph ETP, and mixograph BWE. Overall, GI values were more stable across increasing levels of nitrogen fertilizer and resultant increased protein content compared with SDSS, mixograph development time, and alveograph W and L, suggesting it is a good test for estimating intrinsic gluten strength for cultivars with a wide range of protein content.
Effects of Modified Processing Conditions on Oxidative Properties of Semolina Dough and Pasta
Authors: Borrelli G. M. , De Leonardis A. M. , Fares C. , Platani C. , Di Fonzo N. 
Published: June 2007

ABSTRACTDuring pasta making, semolina is subject to various modifications that are mainly related to oxidative activities with relative effects on some of its components. To evaluate the involvement of hydroperoxidation and bleaching of lipoxygenase (LOX) and peroxidase (POD) activities on loss of pigments and ‐SH groups, their behavior in semolina and during processing was analyzed. Processing was done in standard and four experimental conditions, applying chemical (pH 5.0 and 8.0) and physical (10 and 40°C) treatments, during the mixing and extrusion phases, to study their effects on components. Results pointed out that treatments principally affected hydroperoxidation and bleaching activities of LOX rather than the POD. During pasta making, enzymatic activities showed the same trend in all cultivars, and this was reproducible in all the experimental conditions. Temperature effects on preservation of components were modest, whereas pH 8.0 improved the residual pigment and ‐SH group content in pasta, probably because of the concomitant reduction of oxidative enzyme levels. Finally, out of the four investigated wheat cultivars, Cosmodur showed the best performance in the experimental conditions applied. In fact, high pigment content and yellow index associated with low oxidative activity levels in semolina and in processing samples resulted in better pasta color. Such findings have confirmed that breeding and technological approaches may play an important role in the control of oxidative activities during pasta making, preserving the constituents that positively influence the final pasta color.
Relationship Between the Qualitative and Quantitative Compositions of Gluten Protein Types and Technological Properties of Synthetic Hexaploid Wheat Derived from Triticum durum and Aegilops tauschii
Authors: Wieser Herbert , Hsam Sai L. K. , Zeller Friedrich J. 
Published: June 2007

ABSTRACTThe contribution of the diploid wheat species Aegilops tauschii (Coss.) Schmall to the technological properties of bread wheat (Triticum aestivum L.) was previously studied by the investigation of synthetic hexaploids derived from tetraploid durum wheat (T. turgidum L.) and three diploid Ae. tauschii lines. The results indicated that bread volume, gluten index, SDS‐sedimentation volume, and maximum resistance of gluten were significantly influenced by the Ae. tauschii lines. To determine the relationship between technological properties and qualitative and quantitative compositions of gluten proteins, the flours of parental and synthetic lines were extracted using a modified Osborne fractionation. Gliadin and glutenin fractions were then characterized by reversed‐phase (RP) HPLC on C8 silica gel. The HPLC patterns revealed typical differences between synthetic and parental lines. The gliadin patterns of three synthetic lines and the glutenin patterns of two synthetic lines were more similar to that of the diploid Ae. tauschii parents involved in the hybrids. In the glutenin pattern of one synthetic line, characteristics from both Ae. tauschii and the durum wheat parents were observed. The amount of total gliadin and gliadin types of the synthetic lines was mostly intermediate between those of the durum and Ae. tauschii parents. The amounts of total glutenin and glutenin types (HMW and LMW subunits) of the synthetic lines were generally higher than those of the parental lines, and the ratio of gliadins to glutenins was significantly decreased. High positive correlations were found between the amount of total glutenins, HMW, and LMW subunits and bread volume, maximum resistance and extension area of gluten, and SDS‐sedimentation volume. The ratio of gliadins to glutenin subunits had a strong negative influence on these properties. The protein content of the flours and the amount of total gluten proteins were not correlated with any of the technological properties. Results on the relationship between biochemical characteristics and the breadmaking properties indicated that wheat prebreeding would benefit from studies on protein types and quantification in the choice of parents. In addition, the potential of the diploid Ae. tauschii for improvement of breadmaking quality should be further exploited.
Solid‐Phase Microextraction Method for Headspace Analysis of Volatile Compounds in Bread Crumb
Authors: Ruiz J. A. , Quilez J. , Mestres M. , Guasch J. 
Published: June 2007

ABSTRACTA solid‐phase microextraction method was developed to analyze volatile compounds in bread crumb. Three different fibers usually used to determine volatile compounds in foodstuffs were tested, and Carboxen/ Polydimethylsiloxane showed the best extraction efficiency. This method can determine ≈65 compounds, although only the main compounds responsible for the crumb aroma profile (6 alcohols, 5 aldehydes, 5 acids, and 2 ketones) were evaluated quantitatively with a relative standard deviation <20% and limits of detection were 1–18 mg/kg. All the compounds showed a good linearity in concentration ranges of interest with acceptable correlation coefficients (r > 0.99) and recoveries close to 100%. The optimized solid‐phase microextraction (SPME) method was applied to determine aromatic compounds in some precooked frozen breads marketed in Spain (baguettes and ciabattas).
Effect of Hydroxypropylation on Retrogradation and Water Dynamics in Wheat Starch Gels Using 1H NMR
Authors: Choi S. G. , Kerr W. L. 
Published: June 2007

ABSTRACTThe water dynamics in gels made from native wheat starch, control (alkali‐treated) starch, and hydroxypropylated starch were studied using 1H NMR relaxometry. Transverse relaxation studies showed that at least two domains of water exist in the starch gel, one with a T2 of 0.5–8 msec and one with a T2 at 8–200 msec. For starch gels held at 5°C for up to 15 days, the peak T2 of both regions decreased with time for gels made from native starch, but not for those made from hydroxypropylated starch. Changes in integrated signal in each region suggests that water migrates out of the lower T2 domain during retrogradation. Gels made from isolated amylose had a single, relatively mobile water domain, with T2 dependent on gel concentration. This fraction did not change during storage at 5°C. Granule‐rich gels showed two water domains, one with a T2 range similar to that for amylose gels, which varied over time and were thermally reversible. During storage, most significant changes occurred in the relatively low T2 region associated with granule remnants. These studies show that, in addition to changes in starch during retrogradation, water dynamics are also affected by recrystallization and chemical modification of starch molecules.
Protein Quality of Wheat Desirable for Making Fresh White Salted Noodles and Its Influences on Processing and Texture of Noodles
Authors: Park Chul Soo , Hong Byung Hee , Baik Byung‐Kee 
Published: June 2007

ABSTRACTProtein characteristics of wheat flours from various wheat classes, and of commercial flours for making noodles, were evaluated to determine the effects of protein content and quality on processing and textural properties of white salted noodles, as well as to identify protein quality required for making white salted noodles. SDS sedimentation volume based on constant protein weight, mixograph mixing time, and proportions of salt‐ and alcohol‐soluble protein of three commercial flours for making noodles were more similar to those of hard wheat than to soft wheat flours. SDS sedimentation volume of commercial flours for making noodles based on constant protein weight ranged from 38.5 to 40.0 mL and was higher than those of most soft wheat flours. Mixograph mixing time and proportion of salt‐soluble protein of hard and commercial flours for making noodles were >145 sec and mostly <13.8%, respectively, while those of club and soft wheat flours were < 95 sec and >15.0%. Both protein content and protein quality, as determined by SDS sedimentation volume based on constant protein weight, mixograph mixing time, proportion of salt‐soluble protein, and score of HMW‐GS compositions correlated with optimum water absorption of noodle dough and hardness of cooked white salted noodles.
Structural Changes of Debranched Corn Starch by Aqueous Heating and Stirring
Authors: Han J.‐A. , BeMiller J. N. , Hamaker B. , Lim S.‐T. 
Published: June 2007

ABSTRACTAqueous dispersions (2 mg/mL) of debranched corn starches of different amylose contents (waxy, normal, and high‐amylose) were subjected to extensive autoclaving and boiling‐stirring, and then the changes in starch chain profile were examined using medium‐pressure, aqueous, size‐exclusion column chromatography. As autoclaving time increased from 15 to 60 min, weight‐average chain length (CLw) of waxy, normal, and high‐amylose corn starches determined using pullulan standards decreased from 46 to 41.2, from 122.1 to 96.3, and from 207.3 to 151.8, respectively. Number‐average chain length (CLn) measured by the Nelson‐Somogyi method also decreased from 23.0 to 18.4, from 26.4 to 21.8, and from 66.5 to 41.5, respectively, indicating that thermal degradation of starch chains occurred. The CLw/CLn ratio for normal corn starch was higher than that for waxy corn starch, indicating an increase in polydispersity of the amylose fraction. Thermal degradation was also observed when the debranched starch was subjected to the boiling‐stirring treatment (0–96 hr). During 96 hr, the CLw and relative proportion of B≥2 chains of amylopectin released by debranching waxy corn starch increased, whereas those of B1 chains decreased. This change may indicate physical aggregation of B1 chains. But branches from normal and high‐amylose corn starches showed increases in CLw and the proportion of both B1 and B≥2 chains, along with substantial decreases in those of amylose chains. Therefore, thermal degradation of amylose was greater than that of amylopectin.
Levels of Avenanthramides and Activity of Hydroxycinnamoyl‐CoA:Hydroxyanthranilate N‐Hydroxycinnamoyl Transferase (HHT) in Steeped or Germinated Oat Samples
Authors: Bryngelsson Susanne , Ishihara Atsushi , Dimberg Lena H. 
Published: June 2007

ABSTRACTConcentrations of avenanthramides and activity of the biosynthetic enzyme hydroxycinnamoyl‐CoA:hydroxyanthranilate N‐hydroxycinnamoyl transferase (HHT) were analyzed in dry or, steeped nonmilled or milled, non‐heat‐treated (raw) or heat‐treated oat samples (Avena sativa L.). Increased avenanthramide concentrations were found when intact raw groats were steeped. The increase was time‐ and temperaturedependent and maximal after 10 hr of steeping at 20°C. Continuous germination in air, after steeping, only contributed to a further increase in avenanthramides when steeping times were shorter than 10 hr. Concentrations of avenanthramides and HHT activity were positively correlated during steeping of intact groats at 8 and 20°C. The increase in avenanthramides was suggested to be due to de novo synthesis and a whole grain structure seemed to be required as no increase was found when groats were milled before steeping. Avenanthramide levels also increased when heat‐treated samples, lacking HHT activity, were steeped. This increase may be due to release of bound forms, possibly formed during the preceding heat treatment.
Long‐Term Storage Effect in Frozen Dough by Spectroscopy and Microscopy
Authors: Esselink Eddy F. J. , van Aalst Henrie , Maliepaard Manuelle , van Duynhoven John P. M. 
Published: June 2007

ABSTRACTStorage of dough at low temperatures (‐20°C) has a considerable effect on the final quality of baked bread; this is most obviously reflected in lowered specific volumes. In this study, a suite of structural characterization techniques is applied to examine the underlying mechanism of storage damage at the molecular, microstructural, and macroscopic level. By using infrared spectroscopy, the dehydration of the gluten component could be established at the molecular level, and its kinetics could be monitored in time. Time‐domain nuclear magnetic resonance (NMR) showed increased water mobility, which could be attributed to a release of water from the gluten matrix. At the microstructural level, the growth of ice crystals could be monitored by means of cryogenic scanning electron microscopy (cryo‐SEM). These ice crystals are preferably formed in gas cells with kinetics that are slower than those during infrared spectroscopy but similar to those in time‐domain NMR. At the macroscopic level, ice crystals are not evenly distributed over the molded dough, nor are the gas cells homogeneously distributed over the dough. This has implications for the macroscopic water distribution during frozen storage, which could be substantiated by magnetic resonance imaging (MRI) measurements.
Impact of Industrial Dough Processing on Structure: A Rheology, Nuclear Magnetic Resonance, and Electron Microscopy Study
Authors: Esselink Eddy , van Aalst Henrie , Maliepaard Manuelle , Henderson Thijs M. H. , Hoekstra Niko L. L. , van Duynhoven John 
Published: June 2007

ABSTRACTDough processing is an important factor determining the quality of bread. The most important mechanical steps in industrial dough processing are kneading, extrusion, and molding. In all of these processing steps, considerable changes in the structure and properties of the dough can occur. On a laboratory‐scale level, these (structural) effects are well characterized but, so far, no systematic study has been performed at the level of a large‐scale industrial dough processing line. The molecular and microstructural changes that can take place during industrial dough processing were studied with the help of nuclear magnetic resonance (NMR), fundamental rheology, and scanning electron microscopy (SEM). After the kneading step, the dough shows a well‐developed gluten network with a homogeneous dispersion of starch particles (at optimum kneading time). After the extrusion step (a sheeting procedure), the structure of the dough becomes coarser and the dough gluten network is oriented and partially disrupted. This is accompanied with an increase in both rheological stress and water mobility. After molding, the network structure is restored and both the rheological stress and the mobility of water decrease. These findings provide a novel microstructurally‐lead approach to make recommendations for optimization of industrial dough processing lines.