bluuebunny/crossref_metadata_2025_split huggingface dataset:
Large‐Scale Purification and Characterization of Barley Limit Dextrinase, a Member of the α‐Amylase Structural Family
Authors: Kristensen Michael , Planchot Véronique , Abe Jun‐ichi , Svensson Birte 
Published: June 2007

ABSTRACTHomogeneous barley limit dextrinase (LD) was isolated on a large scale in a yield of 9 mg/kg of 10‐day germinated green malt. This represents a 9,400‐fold purification and 29% recovery of the activity in a flour extract in 0.2M NaOAc (pH 5.0) containing 5 mM ascorbic acid. The purification protocol consists of precipitation from the extract at 20–70% saturated ammonium sulfate (AMS), followed by diethylaminoethyl (DEAE) 650S Fractogel anion‐exchange chromatography, and affinity chromatography on β‐cyclodextrin‐Sepharose in the presence of 2M AMS. LD was eluted by 7 mMβ‐cyclodextrin and contains a single polypeptide chain of 105 kDa (SDS‐PAGE) and pI 4.3. Sequence analysis of tryptic fragments, prepared from 2‐vinylpyridinylated LD and purified by RP‐HPLC, identified short motifs recognized in β‐strand 2, 3, and 5 characteristic of a catalytic (β/α)8‐barrel domain of the α‐amylase family of amylolytic enzymes. Barley LD has ≈50 and 85% sequence identity to bacterial pullulanases and rice starch debranching enzyme, respectively. By using 1H‐NMR spectroscopy, LD hydrolyzes specifically α‐1,6‐glucosidic linkages in pullulan and a branched oligodextrin, 62‐O‐α‐maltotriosyl‐maltotriose, with retention of the α‐anomeric configuration. β‐Cyclodextrin competitively inhibits the LD activity with Ki of 40 μM, while Ki is 1.9 mM and 2.4 mM for α‐cyclodextrin and γ‐cyclodextrin, respectively.
Substitution of Concentrated Ethanol for Water in the Laboratory Washing Fractionation of Protein and Starch from Hydrated Wheat Flour
Authors: Robertson G. H. , Cao T. 
Published: June 2007

ABSTRACTAn unprecedented, ethanol‐based, washing process was used at a laboratory scale to produce both concentrated protein and starch fractions from hydrated wheat flour. In this multistep process, flour was first hydrated and mixed to a batter and then chilled and rested. The cold batter was then mixed and washed in chilled and concentrated ethanol using a modified device that normally applies the water‐based Martin process. Control of the separation was affected by each of these steps. For instance, the hydration of the flour, the time of mixing, the temperature of the wash, the ethanol concentration, and the time of washing were influential. The method produced a gluten concentrate similar in yield and protein content to that reported for a pilot‐scale Martin process but without the need for added salt. Notably, ethanol washing resulted in nonsticky, partially disintegrated curds that dried easily, whereas water washing resulted in a sticky, glutinous, cohesive mass that dried slowly. The process has commercial potential to reduce water and energy use, reduce wastewater generation and environmental impact, and improve product recovery. The process also has the potential to reduce the capital complexity of the drying step and create convenient opportunities for protein subfractionation.
Starch Molecular Mass and Size by Size‐Exclusion Chromatography in DMSO‐LiBr Coupled with Multiple Angle Laser Light Scattering
Authors: Yokoyama W. , Renner‐Nantz J. J. , Shoemaker C. F. 
Published: June 2007

ABSTRACTThe weight average molar mass (Mw) and root mean square radii of starches from waxy maize (Amioca), waxy rice flour, cassava, Hylon V, Hylon VII, and potato amylose were determined by size‐exclusion chromatography (SEC) and multiple‐angle laser light scattering (MALLS). Dimethylsulfoxide (DMSO) containing 50 mM LiBr was used to dissolve the starches and also served as the mobile phase. SEC with large particle size polystyrene divinylbenzene packing materials and MALLS instrumentation were evaluated for the ability to separate and determine molar mass (MM) of starch polymers, respectively. The determination of Mw by MALLS is necessary because the Mw of many cereal starches exceeds the available molecular standards by one or two orders of magnitude. The Mw depends on the method of calculation. The Mw (Berry method) of starch from waxy corn was 2.27 × 108 Da, waxy rice 8.9 × 107 Da, cassava 5.7 × 107 Da, Hylon V 2.7 × 107 Da, Hylon VII 4.8 × 106 Da, and potato amylose 1.9 × 105 Da. Recovery dropped dramatically for molecules with root mean square radii >200 nm.
Improvement of Brown Bread Quality by Prehydration Treatment and Cultivar Selection of Bran
Authors: Nelles Elizabeth M. , Randall Philip G. , Taylor John R. N. 
Published: June 2007

ABSTRACTDifferent bran pretreatments and bran cultivars were investigated with the aim of alleviating the adverse effects caused by bran addition in brown (fiber‐rich) bread. Three different bran treatments: hydration, wet heat, and wet oxidation, all hydrate bran before its addition to other breadmaking ingredients. Four different bran cultivars were investigated. All treatments improved brown bread quality significantly, resulting in larger, softer loafs. All treatments resulted in an increase in the water absorption of brown bread doughs and a decrease in potentially oxidizable substances (POS) in brans. It is suggested that prehydration treatment activates bran lipoxy‐Different bran pretreatments and bran cultivars were investigated with the aim of alleviating the adverse effects caused by bran addition in brown (fiber‐rich) bread. Three different bran treatments: hydration, wet heat, and wet oxidation, all hydrate bran before its addition to other breadmaking ingredients. Four different bran cultivars were investigated. All treatments improved brown bread quality significantly, resulting in larger, softer loafs. All treatments resulted in an increase in the water absorption of brown bread doughs and a decrease in potentially oxidizable substances (POS) in brans. It is suggested that prehydration treatment activates bran lipoxygenase which oxidizes POS in bran, reducing bran's contribution to brown bread dough. A further reduction of these substances is caused by a washout effect of the treatments. On average across all bran cultivars, the hydration and wet oxidation treatments improved brown bread quality significantly more than the wet heat treatment, which also reduced the bran POS significantly less than the other treatments, probably due to its rapid inactivation of lipoxygenase. The bran cultivars differed significantly in their effects on brown bread quality, suggesting that bran selection according to cultivar should be considered.
Effects of Oat Grain Hydrothermal Treatments on Wheat‐Oat Flour Dough Properties and Breadbaking Quality
Authors: Zhang D. , Moore W. R. , Doehlert D. C. 
Published: June 2007

ABSTRACTHydrothermal treatments, which are routine in oat processing, have profound effects on oat flour dough rheological properties. The influence of roasting and steam treatments of oat grain on dough mixing and breadbaking properties was investigated when hydrothermally treated oat flour was blended with wheat flour. Roasting of oat grain (105°C, 2 hr) resulted in oat flours that were highly detrimental to wheat flour dough mixing properties and breadbaking quality. Steaming (105°C, 20 min) or a combination of roasting and steaming of oat grain significantly improved the breadbaking potential of the oat flours. The addition of oat flours increased water absorption and mixing requirements of the wheat flour dough and also decreased bread loaf volume. However, at the 10% substitution level, steamed oat flours exhibited only a gluten dilution effect on bread loaf volume when wheat starch was used as a reference. Oat flour in the breadbaking system decreased the retrogradation rate of bread crumb starch. The results indicate that adequate hydrothermal treatments of oat grain are necessary for oat flour breadbaking applications. Steamed oat flours used at a 10% level retarded bread staling without adversely affecting the loaf volume.
Enzymatic Hydrolysis of Barley Starch Lipids
Authors: Shamekh S. , Mustranta A. , Poutanen K. , Forssell P. 
Published: June 2007

ABSTRACTThe efficiency of phospholipase and lipase preparations in the hydrolysis of lysophospholipids of native and gelatinized barley starch was examined. The degree of hydrolysis was analyzed by determination of the amount of released fatty acids by an enzymatic method. Thermal and structural properties of the enzyme‐treated starch were studied by differential scanning calorimetry and light microscopy. Lysophospholipids of the gelatinized barley starch were easily hydrolyzed, in contrast to the lipids of the granular starch. The maximum degree of hydrolysis achieved for the gelatinized starch was 80% and for the native starch ≈20%. Gelatinization enthalpies and micrographs indicated that even though the amount of the released fatty acids from the native starch was small, formation of free fatty acids inhibited swelling and gelatinization of starch granules.
Effects of (1→3)(1→4)‐β‐d‐Glucans of Wheat Flour on Breadmaking
Authors: Wang Lin , Miller R. A. , Hoseney R. C. 
Published: June 2007

ABSTRACTWater‐soluble nonstarch polysaccharides were extracted from commercial hard red winter wheat flour and separated into three fractions by graded ethanol precipitation. The three fractions, F15, F40, and F60, varied in polysaccharide composition. Fraction F15 was rich in watersoluble (1→3)(1→4)‐β‐d‐glucans, and fractions F40 and F60 were rich in arabinoxylans. Addition of individual fractions to a bread formula did not affect bread loaf volume. Addition of fraction F15 to the formula improved bread crumb grain. Treatment of (1→3)(1→4)‐β‐D‐glucan‐rich fraction F15 with lichenase before its addition to the bread formula resulted in bread with poor crumb grain. Treatment of the F15 fraction with β‐xylanase before its addition to the bread formula resulted in bread with slightly improved crumb grain. Presumably, the (1→3)(1→4)‐β‐D‐glucans in fraction F15 improved crumb grain by stabilizing air cells in the bread dough and preventing coalescence of the cells. Addition of pentosan‐rich fractions F40 and F60 to the bread formula did not improve crumb grain and interfered with the improving effect of (1→3)(1→4)‐β‐D‐glucan‐rich fraction F15. Hydrolysis of the arabinoxylans in flour by adding β‐xylanase to the bread formula resulted in improved crumb grain.
Steam Flaking Characteristics of Sorghum Hybrids and Lines with Differing Endosperm Characteristics
Authors: McDonough C. M. , Anderson B. J. , Acosta‐Zuleta H. , Rooney L. W. 
Published: June 2007

ABSTRACTCommercial and food‐type sorghum hybrids with differing kernel and endosperm characteristics were grown under comparable conditions and steam flaked in each of three years. The raw‐grain kernel characteristics and proximate analyses were homogenous over the three‐year period. The waxy hybrid produced large, translucent, durable flakes that had significantly higher enzyme‐susceptible starch values for all years compared to the other varieties. Flakes with lower amylose contents (waxy endosperm) were positively correlated with percent whole flakes (r2 = 0.509), flake diameter (r2 = 0.846), and enzyme‐susceptible starches (r2 = 0.564) and negatively correlated with higher flake fragility (r2 = ‐0.647), test weight (r2 = ‐0.626), and flake breakage (r2 = ‐0.560). The heterowaxy flakes had a good appearance and were generally comparable in quality to the nonwaxy commercial and experimental hybrids. Heterowaxy sorghum hybrids with good grain yields can provide improved quality grain and flakes without sacrificing agronomic performance and yields. No difference in flaking performance was detectable among the kernels with different pericarp colors; flakes from the white food‐type sorghums had excellent appearance. Nontempered control samples were inferior in quality to all conditioned treatments.
Effects of Pollination Method and Growing Location on Starch Thermal Properties of Corn Hybrids
Authors: Krieger K. M. , Pollak L. M. , Brumm T. J. , White P. J. 
Published: June 2007

ABSTRACTStarch gelatinization and retrogradation properties of corn were studied to determine the effect of controlled (self) pollination versus noncontrolled pollination on analytical determinations, and the potential to eliminate the expensive and time‐consuming step of self‐pollinating before research screening of corn genotypes. Twenty‐four hybrids were grown in two Iowa locations, Story City and Ames. At Story City, all hybrids received three pollination treatments: self‐pollination; small‐plot, openpollination (representing corn from small test plots); and large‐plot, openpollination (representing corn from a farmer's field). Self‐pollinated and small‐plot, open‐pollinated corn were grown in replicated two‐row plots, whereas large‐plot, open‐pollinated corn was grown in unreplicated plots of 12.8 m × 8 rows. At Ames, the small‐plot, open pollination treatment was not done. Starch was extracted from samples of corn harvested from each plot, and gelatinization and retrogradation properties were determined using differential‐scanning calorimetry (DSC). Hybrids exhibited different starch gelatinization and retrogradation properties. Significant differences (P ≤ 0.05) in starch gelatinization and retrogradation properties occurred among pollination methods and between locations. Pollination method did not influence gelatinization enthalpy values, but onset temperature values for gelatinization, and range values for retrogradation differed significantly among pollination methods. At Ames, treatments gave different values for retrogradation enthalpy and percentage of retrogradation. Because of differences in some starch characteristics associated with pollination methods, self‐pollination is recommended when growing samples in small plots for research purposes.
Discovery of Grain Sorghum Germ Plasm with High Uncooked and Cooked In Vitro Protein Digestibilities
Authors: Weaver Charlotte A. , Hamaker Bruce R. , Axtell John D. 
Published: June 2007

ABSTRACTGrain sorghum has been documented to have low protein digestibility relative to other cereal grains. Low protein digestibility of sorghum is most pronounced in cooked foods and is ranked slightly lower than corn as a feed grain. In this article, sorghum germ plasm is identified that has substantially higher uncooked and cooked flour in vitro protein digestibility than normal cultivars. Sorghum lines were found within a high‐lysine opulation derived from the mutant P721Q that have ≈10–15% higher uncooked and ≈25% higher cooked protein digestibilities using a pepsin assay. Highly digestible sorghum grain showed little reduction in digestibility after cooking, compared to the large reduction that is typical of normal sorghum cultivars. Using the three‐enzyme pH‐stat method, we showed that the highly digestible lines had the same degree of peptide bond hydrolysis in ≈5 min, as was found in 60 min in the normal cultivar, P721N. Differences in protein digestibility were related to enyzme susceptibility of the major storage prolamin, α‐kafirin, that comprises ≈50–60% of the total sorghum grain protein. Using the enzyme‐linked immunosorbent assay (ELISA) technique to track the pepsin digestion of α‐kafirin, the highly digestible lines had ≈90–95% α‐kafirin digested in 60 min compared to 45–60% for two normal cultivars. γ‐Kafirin, a minor structural prolamin found mainly at the periphery of protein bodies, was also somewhat more digestible in the highly digestible sorghums. Highly digestible grain was of a floury kernel type, though recently this trait has been found in a modified background. More digestible protein from sorghum grain, that additionally is high in lysine content and has a fairly hard endosperm, could be of important benefit to populations who lack adequate protein in their diets, and may, pending further studies, prove to increase the value of sorghum as a feed grain.
A Rapid General Method for Appraising the Rheological Properties of the Starchy Endosperm of Cereal Grains
Authors: Haddad Y. , Benet J. C. , Abecassis J. 
Published: June 2007

ABSTRACTA rapid, simple method was developed to prepare small, parallelepipedal test samples of endosperm of wheat, corn, and rice grains. Compression tests performed on endosperm samples revealed the following mechanical properties: modulus of elasticity (E, GPa), breaking stress (σrup, MPa), and maximum breaking strain (∊rup, %). All tests were performed on several endosperm test samples of each cereal species. The results displayed good repeatability and several significant differences in the mechanical behavior of different endosperm structures, especially among soft, hard, and durum wheats. Rice and corn endosperm displayed mechanical behavior similar to that of durum wheat endosperm. The method proposed appears to be sufficiently sensitive and repeatable for studying the incidence of hardness and vitreousness of cereal grain endosperm in relation to its suitability for milling.
Role of Phosphorus in Viscosity, Gelatinization, and Retrogradation of Starch
Authors: Lin P.‐Y. , Czuchajowska Z. 
Published: June 2007

ABSTRACTThe effect of starch crystallinity and phosphorus on starch gelatinization and retrogradation were studied using wide‐angle X‐ray powder diffraction, cross polarization/magic angle spinning (CP/MAS) 13C nuclear magnetic resonance (NMR) spectroscopy, 31P NMR spectroscopy, Rapid Visco Analyzer (RVA) and differential scanning calorimetry (DSC). Two starches differing significantly in peak viscosity (cv. Stephens, 283 BU; cv. Crew, 560 BU) were comparable in amylose content and starch crystallinity, while differing significantly in phospholipids content. Starch of lower peak viscosity had a higher phospholipids content and showed a slower rate of retrogradation. Starch from Stephens (0.098% phosphorus) had an enthalpy value of retrograded starch of 2.2 J/g after 14 days of storage, while starch from Crew (0.062% phosphorus) had an enthalpy value as high as 4.4 J/g. Defatting with a hot n‐propanol and water (3:1) mixture caused substantial changes in peak viscosity. Peak viscosity for starch from Crew decreased by 75 RVU due to defatting, while starch from Stephens decreased by as much as 125 RVU. After defatting with the hot n‐propanol water mixture, the rate and extent of starch retrogradation were comparable between the prime starches, which differed significantly in peak viscosity.
Granule Size Distribution and Chemical Composition of Starches from 12 Soft Wheat Cultivars
Authors: Raeker M. Ö. , Gaines C. S. , Finney P. L. , Donelson T. 
Published: June 2007

ABSTRACTGranule size distribution of wheat starch is an important characteristic that can influence its chemical composition, which in turn may affect its functionality. The granule size distribution and chemical composition of soft wheat starches were characterized and compared and relationships among those properties were identified. Thirty‐four starch samples from 12 soft wheat cultivars grown in the eastern half of the United States were examined. Granule size distribution was characterized using a laser light‐scattering technique. Amylose and phospholipid contents were determined using colorimetric procedures. A clear trimodal distribution of granule sizes was shown by 26 out of 34 starch samples: small granules with diameters <2.8 μm, midsize granules with diameters of 2.8–9.9 μm, and large granules with diameters >9.9 μm. Volume% distribution of granules within the three size classes had ranges of 9.7–15.2% (small), 13.4–27.9% (medium), and 57.9–76.9% (large). Highly significant differences were seen among the cultivars for volume% of granules within the ranges of 9.9–18.5 μm and 18.5–42.8 μm. Cultivar specific surface area means also differed. The environment affected granule size distribution, with some cultivars exhibiting more variation than others. Pioneer 2555 was the least variable, whereas Pioneer 2550 and Geneva were the most variable cultivars. Mean total amylose (TAM), apparent amylose (AAM), and lysophospholipid (LPL) values varied significantly among cultivars. TAM was positively correlated with the volume% of granules of 9.9–18.5 μm. LPL was negatively correlated with mean starch granule diameter and positively correlated with specific surface area of granules, indicating smaller granules tended to have higher lipid contents. Results suggest that significant differences exist in granule size distribution of soft wheat starches and affect starch chemical composition. Data also suggest it is possible that lipid is preferentially associated with the biosynthesis of small starch granules.
Influence of Barley and Malt Storage on Lipoxygenase Reaction
Authors: Kaukovirta‐Norja A. , Reinikainen P. , Olkku J. , Laakso S. 
Published: June 2007

ABSTRACTThe dioxygenation of linoleic acid (LA) by aqueous flour suspensions of barley and malting samples was studied. The rate of this lipoxygenase (LOX) reaction varied as the malting process proceeded, giving a characteristic LOX reaction profile for a malting. The differences in the profiles from one malting to another were dramatic. It also appeared that during storage of dry, intact kernel samples from a single malting, a reduction in the rate of LOX reaction always occurred, and the rates of reduction with time were dependent on the stage of malting at the time of sampling. The kinetics of this aging could roughly be divided into four categories representing different stages of malting. Consequently, greatly varying LOX reaction profiles can be obtained from a single malting depending on the time of storage of kernels before assays. The results indicate that steeping, germination and the subsequent drying render the state of kernels unstable with respect to the LOX reaction for at least two to three weeks. Homogeneity of malt quality is important in the further applications of malt, especially in the brewing industry. Therefore, the rate of LOX reaction should be considered as a quality factor of malt.