bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Lysine on Growth of Tilapia Fed Diets Rich in Corn Gluten Meal
Authors: Wu Y. Victor , Rosati Ronald R. , Brown Paul B.
Published: June 2007

Tilapia is a warmwater fish with mild flavor. Nearly 8.6 million kg are produced domestically, and ≈22.7 million kg are imported. Corn gluten meal (60% protein fraction) is a product obtained from wet‐milling of corn. Diets (36% protein) containing 36–44% corn gluten meal with different levels of lysine and fish meal were formulated and fed to tilapia in aquaria for 12 weeks. Weight gain (WG) of tilapia fed diets containing the highest level of lysine (7.4% protein) with 4% fish meal was equal to that of fish fed a commercial control diet. Diets with lower lysine resulted in lower WG. The feed conversion ratio (FCR) and protein efficiency ratio (PER) of tilapia fed experimental diets containing adequate levels of essential amino acids and fish meal were the same as for fish fed the commercial control diet (also containing fish meal). Fish fed diets containing lower lysine levels had less favorable FCR and PER. This study shows that corn gluten meal is utilized at high levels in tilapia diets, particularly if essential amino acids are provided in adequate amounts.
Comparison of Water Absorption Patterns in Two Barley Cultivars, Using Magnetic Resonance Imaging
Authors: McEntyre E. , Ruan R. , Fulcher R. G.
Published: June 2007

Two barley cultivars, Excel and Prisma (six‐row and two‐row types, respectively), were obtained from the 1993 harvest at Crookston, MN. Magnetic resonance imaging (MRI) was used to follow water imbibition in single, large seeds of Excel and Prisma barley. A comparison of moisture distribution on longitudinal sections of Prisma and Excel barley during early hours of steeping was then made. MRI analysis revealed that the majority of water initially entered the kernel through the kernel surfaces and into the endosperm tissues. Water was observed under the surface of the hull tissues and appeared to be migrating into the aleurone and endosperm tissues. Then water was detected moving from the embryo to the scutellum and then into the crushed cell layers. Aleurone and embryo tissue showed more rapid water uptake and distribution than did scutellar tissue. Some transient water distribution was observed in the scutellum, ventral furrow, and vascular tissues. This indicates that the hydration of surface tissues and crushed cell layers may be significant during the early hours of steeping. During the late hours of steeping, the crushed cell and endosperm cavity region appears to become remarkably active in water transport. Water was distributed throughout the endosperm tissue of the Prisma cultivar more efficiently than in that of the Excel cultivar, although Excel absorbed more water initially.
Volatiles in Selected Commercial Breads
Authors: Seitz L. M. , Chung O. K. , Rengarajan R.
Published: June 2007

Selected types of commercial breads obtained from local markets, including white sandwich, Irish oatmeal, soft rye, hearty rye, sour dough, home‐like white, and onion‐basil, were analyzed for volatiles. Using a purge and trap instrument, volatiles were purged directly from fresh crumb and crust samples of each bread type, collected on a trap (Tenax‐TA), and transferred to a gas chromatograph. Separated components were detected and identified using mass and infrared spectroscopic detectors. Many components were present in all of the bread samples, with relative amounts varying among bread types and crust and crumb samples of a given bread type. Alcohols were generally the most abundant, followed in approximate order by aldehydes, esters, ketones, acids, various aromatics, terpenes, and hydrocarbons. Flavor additives, such as limonene, carvone, and other related compounds, were found mostly in rye and onion‐basil breads. Composition of volatiles from sour dough bread differed greatly from the other breads, especially in increased levels of aldehydes, acids, and certain esters. Unsaturated aldehydes, such as 2‐hexenal and 2‐heptenal, were most abundant in sour dough bread.
Polymorphism of Aspartic Proteinases in Resting and Germinating Barley Seeds
Authors: Zhang Ningyan , Jones Berne L.
Published: June 2007

Both resting and germinated barley seeds (Hordeum vulgare L. ‘Morex’) contain aspartic endopeptidase activities, and the activities increase during germination. We have extracted and partially purified aspartic endopeptidases from both resting seeds and green malt (four‐day germinated barley). Six aspartic proteinase activities were found in resting barley seeds while only four activities were detected in green malt. All of the aspartic proteinases had similar pH activity optima (pH 3.5–4.5) and pI values (≈4.5). The purified green malt aspartic proteinases selectively digested a group of barley seed proteins, postulated to serve as defensive proteins, that are coded by the amylase‐trypsin inhibitor super gene family. The aspartic proteinases that bound to a pepstatin A affinity column at pH 4.5 cross‐reacted with antiserum raised against aspartic proteinases purified from barley seed. However, those that did not bind the affinity column also did not cross‐react with the antiserum, indicating that there are two distinct groups of aspartic proteases in germinating barley.
Effect of Dough Processing Conditions and DATEM on Norwegian Hearth Bread Prepared from Frozen Dough
Authors: Sahlstr⊘m S. , Nielsen A. O. , Færgestad E. M. , Lea P. , Park W. J. , Ellekjær M. R.
Published: June 2007

The objective of this study was to examine treatments that directly influence Norwegian lean doughs destined to be frozen. Therefore a strip‐block experimental design with four dough treatment factors (wheat flour blend, diacetyl tartaric acid esters of monoglycerides [DATEM], water absorption, and dough temperature) and two storage factors (frozen storage time and thawing time) was used. Four levels were selected for frozen storage time and two levels were selected for the remaining factors. After frozen storage (2–70 days), the doughs were thawed and baked. Principal component analysis showed that to obtain a high loaf volume and bread score after freezing, a high dough temperature after mixing (27°C) was essential. The highest form ratio (height/width) level was obtained after 28 days of frozen storage and with a short thawing time (6 hr). Analysis of variance (ANOVA) of dough treatments showed that an increase in dough temperature from 20 to 27°C after mixing resulted in a significant increase in loaf volume (1,653 to 2,264 mL), form ratio (0.64 to 0.69), and bread score (1.7 to 3.2), and a reduction in loaf weight (518.4 to 512.5 g) and crumb score (7.9 to 5.9, i.e., a more open bread crumb). Also, the addition of DATEM significantly increased loaf volume (1,835 to 2,081 mL), form ratio (0.64 to 0.69), and bread score (2.2 to 2.6). Frozen dough storage time significantly affected loaf volume, loaf weight, bread score, and crumb score. Increasing thawing time from 6 to 10 hr significantly increased loaf volume (1,855 to 2,121 mL), and reduced the form ratio (0.69 to 0.63) and loaf weight (516.8 to 511.4 g). ANOVA of the interaction between dough treatment and frozen storage time showed that decreasing water absorption significantly increased the loaf volume.
Evaluation of Starch Properties of Wheats Used for Chinese Yellow‐Alkaline Noodles in Japan
Authors: Akashi Hajime , Takahashi Miwa , Endo Shigeru
Published: June 2007

The objective of the present research was to assess the functional properties of the starches isolated from Australian prime hard wheat (PH) and hard red winter wheat (HRW) in the United States. These wheats are favorably used in Japan for the production of Chinese yellow‐alkaline noodles (YAN). Starches isolated from PH showed higher amylose content than those of noodle wheat but lower than bread wheat. Analysis of swelling power showed that PH starch had lower values than noodle wheat starches but higher values than bread wheat starches. By contrast, HRW starch showed relatively higher amylose content and lower swelling power. There were large differences in the starch pasting properties between PH and HRW. High‐performance size‐exclusion chromatography studies on the components leached from the starch (80°C, 20 min) showed that PH starch had a somewhat characteristic leaching profile. Its peak ratio of high molecular weight region to low molecular weight region was greater than that of HRW starch. PH starch also characterized by having lower endothermal enthalpy (ΔH) in amylose‐lipid transition. The eating quality assessment for YAN revealed that PH had more elastic texture than HRW. Additional reconstitution studies showed that these quality differences could be attributable to its starch properties.
Measurement of the Time‐Dependent Appearance of Discolored Spots in Alkaline Noodles by Image Analysis
Authors: Hatcher D. W. , Symons S. J. , Kruger J. E.
Published: June 2007

Fresh alkaline noodles prepared from patent flours of the Canadian wheat class Canadian Prairie Spring White (CPSW) AC Karma and AC Vista were characterized by image analysis to numerically evaluate the time‐dependent formation of dark areas (spots) on the noodle surface. The system was able to rapidly detect, measure, and characterize such undesirable discolorations, which commonly form on the surface of raw noodles with time. Variations in minimum spot detection size (0.050–0.250 mm2), in combination with a darkness threshold setting (Δ grey scale units of 2, 5, and 10) were investigated. A linear increase in the number of spots was observed over time for both cultivars with nine combinations of size and darkness. The total number of discolored spots measured was dependent on both detection size and sensitivity (threshold setting). Significant differences (P < 0.05) in the number of darkened spots were detected between the two cultivars only after 24 hr. Similarly, significant differences (P < 0.05) in size of the spots between the two cultivars was observed at 24 hr. Darkening was most rapid within the first hour for both cultivars, followed by a period of stability before a significant (P < 0.05) further increase by 24 hr. Characterization of the darkness distribution indicated significantly different distribution profiles for the two cultivars examined, which was consistent with their noodle brightness (L*) values.
Initial Heating Temperature and Native Lipid Affects Ordering of Amylose During Cooling of High‐Amylose Starches
Authors: Boltz Kathryn W. , Thompson Donald B.
Published: June 2007

Formation of ordered structures from disordered amylose is practically important. The thermal behavior of high‐amylose maize starches was studied during cooling, following heating, and during subsequent reheating. Four commercial high‐amylose genotype maize starches with varying amylose contents (ae du, ae su2, and ae [nominally both 50 and 70% amylose]) were heated to either 120, 140, 160, or 180°C, cooled to 5°C, and reheated to 180°C in a differential scanning calorimeter. Each starch was studied with its native lipid, as well as in reduced‐lipid and lipid‐free form. On cooling of lipid‐containing starches, two distinct exotherms were observed and attributed to amylose‐lipid complex formation and to amylose chain association. A distinct exotherm at ≈75°C was attributed to amylose‐lipid complex formation. The exotherm attributed to amylose chain association on cooling varied according to the initial heat treatment, lipid level, and starch type. Starches with higher amylose contents showed larger exotherms on cooling. For initial heat treatments to 120 or 140°C, a broad exotherm beginning at ≈95°C was observed on cooling. In contrast, for initial heat treatments to 160 and 180°C, a sharper exotherm with a peak temperature below ≈55°C was observed. Upon reheating, samples that had been initially heated to 120 or 140°C showed a peak at >140°C that was attributed to the melting of ordered amylose. Starches initially heated to 160 or 180°C did not show this peak. This work illustrates that initial heating temperature, as well as lipid content and amylose content, all affect amylose chain association during cooling. Thus, this work suggests strategies for controlling ordering of amylose during processing.
Effect of Adding Exogenous Oxidative Enzymes on the Activity of Three Endogenous Oxidoreductases During Mixing of Wheat Flour Dough
Authors: Rakotozafy Lalatiana , Mackova Bozena , Delcros Jean‐François , Boussard Aline , Davidou Sylvie , Potus Jacques , Nicolas Jacques
Published: June 2007

The behavior of different exogenous enzymes (soybean lipoxygenase [SLOX], horseradish peroxidase [HPOD], catalase from bovine liver [BCAT], and glucose oxidase [GOX] from Aspergillus niger) added to dough was studied during mixing. The effect of adding these exogenous oxidoreductases on the activity of three oxidative enzymes present in wheat flour (lipoxygenase [WLOX], peroxidase [WPOD], and catalase [WCAT]) was examined. Proper assay conditions were established to differentiate between added WLOX, WPOD, and WCAT and the corresponding activities present in wheat flour. For doughs with added SLOX, an immediate loss of extractable SLOX (≈40%) was observed which remained constant during further mixing. When compared with the control dough, addition of SLOX decreased the losses in WLOX and WCAT activities, whereas WPOD activity was unaffected. With doughs supplemented by HPOD, an immediate loss of 20% in the HPOD activity was observed which did not change after 20 min of mixing. Compared with control dough, addition of HPOD did not affect the behavior of WLOX and WPOD, whereas a slight decrease in the WCAT losses was observed. Addition of BCAT to the dough did not change the behavior of WLOX and WPOD, whereas the losses in WCAT were less rapid. Half of the extractable activity of BCAT was lost at the beginning of mixing with no change during further mixing. For doughs supplemented with GOX, 25% of the GOX activity was lost in the first 5 min of mixing and an additional loss of 20% was observed after 20 min of mixing. Compared with dough without GOX, addition of GOX decreased the losses in WLOX, whereas losses in WCAT and WPOD increased. Glucose and ferulic acid were also added to doughs supplemented with GOX. Added glucose decreased the losses in GOX and WLOX and did not change the behavior of WPOD and WCAT during mixing. Addition of ferulic acid promoted a slight increase of the losses in WLOX and WCAT and almost no change for GOX and WPOD.
Effects of Feed Rate and Screw Speed on Operating Characteristics and Extrudate Properties During Single‐Screw Extrusion Cooking of Rice Flour
Authors: Yeh An‐I , Jaw Yih‐Mon
Published: June 2007

Rice flour (37% moisture content) was used to examine the effects of feed rate and screw speed on the specific energy input during single‐screw extrusion cooking. Torque, raised by decreasing screw speed or increasing feed rate, was found to be a power law function of the ratio of feed rate to screw speed (Fr/Ss) with r2 > 0.94. Specific mechanical energy (SME) calculated from torque also was a power law function of Fr/Ss with r2 >0.84 and negative power law indices. The SME obtained was in the 225–481 kJ/kg range. Thus the extruder can be considered low shear. Increasing SME raised the die temperature and decreased both intrinsic viscosity and water absorption index (WAI). The degree of gelatinization and intrinsic viscosity of extrudates also were power law functions of Fr/Ss. The intrinsic viscosity correlated well with the degree of gelatinization, WAI, and cooking loss, and appeared to be a good index of the extrudate properties. Different screw profiles also affect torque measurement.
Isolation and Identification of a Wheat Flour Compound Causing Sticky Dough
Authors: Huang W. N. , Hoseney R. C.
Published: June 2007

Fractionation and reconstitution studies of a flour from 1B/1R wheat showed that the factor causing sticky dough was water soluble. In addition, these studies showed that enzymes and lipids in the flour were not responsible for producing sticky dough. Dialysis experiments showed that the active component was nondialyzable. Gel‐filtration chromatography of the retentate fraction showed that the substance causing sticky dough contained both a carbohydrate and a UV‐absorbing material. Treatment of the active fraction with base caused the fraction to lose its ability to cause stickiness. The UV‐absorbing material and the carbohydrate fraction had to be covalently linked for the compound to be active. Gas chromatography‐mass spectrometry and HPLC analysis showed that the UV‐absorbing moiety was predominantly trans‐ferulic acid, and the carbohydrate part was a glucose polymer. The glucose polymer was not degraded by α‐amylase but was degraded by lichenase, suggesting that the glucose polymer was a mixed‐linkage β‐glucan.
Physicochemical Properties of Flours that Relate to Sorghum Couscous Quality
Authors: Aboubacar Adam , Hamaker Bruce R.
Published: June 2007

Flours from eight sorghum cultivars were evaluated for their couscous‐making ability with the objective of finding predictive relationships between flour physicochemical properties and couscous quality. Chemical composition, physical characteristics, and pasting and gelatinization properties of the flours were determined. A laboratory procedure was used to prepare couscous. Couscous properties were evaluated and compared to a laboratory‐prepared and a commercial durum wheat couscous. Hard grain produced flours containing a high proportion of coarse particles with low ash and high damaged starch content and yielded a higher proportion of desirable sorghum couscous granules. A variety of colors ranging from brown to yellow were obtained when flours were processed into couscous. Cooked sorghum couscous stickiness was positively correlated (r = 0.89, P < 0.01) with the amount of damaged starch in flour. Cooked couscous hardness correlated positively (r = 0.79, P < 0.05) with apparent amylose content of flour and correlated negatively (r = ‐0.75, P < 0.05) with flour peak viscosity. Durum wheat couscous was lighter and had more yellow color than sorghum couscous. Sorghum couscous was stickier and harder than durum wheat couscous. Addition of 2% oil to the cooking water considerably improved the texture of some sorghum couscous to a level comparable to that of durum wheat couscous.
Starch and Protein Quality Requirements of Japanese Alkaline Noodles (Ramen)
Authors: Crosbie G. B. , Ross A. S. , Moro T. , Chiu P. C.
Published: June 2007

Studies on samples of 20 hard‐grained wheat cultivars and a commercial flour that varied in starch and protein quality showed that both characteristics influenced the texture of Japanese alkaline noodles (ramen). Flour swelling volume (FSV) and flour pasting characteristics (peak viscosity and breakdown) determined with a Rapid‐Visco Analyser (RVA) assessed independently of α‐amylase effects, were negatively correlated with total texture score. Protein quality, as indicated by farinograph stability, was positively correlated with total texture score. RVA pasting characteristics were substantially affected by small levels of α‐amylase, and inactivation by means of 1 mM AgNO3 was a critical requirement in characterizing the quality of the starch component of flour.
Paste Properties of Modified Starches from Partial Waxy Wheats
Authors: Reddy Indira , Seib Paul A.
Published: June 2007

Properties of modified starches from partial waxy wheats have not been examined. Protease digestion of cracked kernels of three hard winter wheats varying in amylose content led to 82–85% recovery of starch, whereas kneading of the flour‐water doughs gave 75–83% recovery. All starches had a protein content of <0.3% and ash content of <0.01%. Granule size distributions showed that starch from Ike kernels contained 86% A‐type granules with a peak size of ≈18μm, and Karl‐92 starch contained 77% A‐type granules with a peak size of ≈16μm. The A‐type granules (82%) from Rio Blanco starch were intermediate in size. The amylose content of Karl‐92 starch, determined by concanavalin‐A precipitation of amylpectin, was 28%, which was 17% higher than that of Ike starch (23%). The amylose content of Rio Blanco starch was 26%. The lipid content of Karl‐92 starch, determined as fatty acid methyl esters, also was 18% higher than that of Ike starch (601 vs. 488 mg/100 g of starch, respectively). Wheat starches were modified with hydroxypropyl (HP) groups to low (1.5–2.5%) and medium (≈4.0%) levels, and the HP starches were cross‐linked with phosphoryl chloride at levels of 0.003–0.075%. Pasting curves (amylograms) showed that Ike starch substituted with a low level of HP and optimally cross‐linked with 0.025% phosphoryl chloride (starch basis) had a greater paste consistency than low HP cross‐linked Karl‐92, and Rio Blanco starches. At 4% HP and optimum cross‐linking (0.003% phosphoryl chloride), the paste consistencies of the modified starches were nearly the same. The clarity of unmodified Ike starch paste was higher than that of Karl‐92 or Rio Blanco starch pastes, and the clarity of all three pastes decreased as cross‐linking was increased. Unmodified Ike starch formed a stronger gel than unmodified Karl‐92 and Rio Blanco starches, but gel properties largely converged as the starches were modified.
A Rapid Method for Quantifying Total Anthocyanins in Blue Aleurone and Purple Pericarp Wheats
Authors: Abdel‐Aal E.‐S. M. , Hucl P.
Published: June 2007

A simple, rapid method for determining total anthocyanins was developed for use in developing wheat cultivars with dark‐blue grains. The method was evaluated as a screening test and for quantification of total anthocyanins in blue and purple wheats and related cereals. Wheat anthocyanins were significantly more extractable in ethanol or methanol than in water at different pH levels. A sample‐to‐solvent ratio of 1:8 at pH 1 and 25°C was used. Anthocyanin extracts of pigmented wheat and barley grains exhibited absorbance spectra similar to cyanidin 3‐glucoside. The absorbance of anthocyanin extracts of 160 blue wheat experimental lines were significantly correlated with whole‐grain Hunterlab color values. Total anthocyanins averaged 157 mg/kg in blue wheat whole meal and 104 mg/kg in purple wheat whole meal, whereas blue wheat bran contained 458 mg/kg as compared with 251 mg/kg in purple wheat bran.
Effect of Zinc and Aluminum Ions in Breadmaking
Authors: Vadlamani Keswara Rao , Seib Paul A.
Published: June 2007

Zinc and aluminum ions as chloride or sulfate salts at 50–500 ppm metal ion (flour basis) had no detrimental effect on fermentation of yeastleavened dough. Increased mixing times (≈10–50%) due to addition of aqueous solutions of zinc (250–500 ppm) or aluminum (150–250 ppm) ions to a bread formula was overcome by withholding salt until the final mixing stage. Breads made from commercial flours (12.5% protein) containing zinc (250–500 ppm) or aluminum (150–250 ppm) ions and no oxidant had improved loaf volume and crumb grain when compared with control bread, and no off‐taste. Additionally, breads with added zinc or aluminum had better crumb grains and slower firming rates when compared with breads containing optimum l‐ascorbic acid (50 ppm) or potassium bromate (20 ppm). Breads made from commercial flours (11.1% protein) and three laboratory flours (11.4–13.6% protein) containing zinc (250 ppm) or aluminum (150 ppm) ions also had improved loaf volumes and crumb grains. Zinc or aluminum ions in combination with l‐ascorbic acid, but not potassium bromate, had a detrimental effect on bread quality. Scanning electron microscopy of freeze‐dried bread doughs revealed that zinc and aluminum ions enhanced the film‐coating property of gluten. One serving (one slice, 28 g) of bread made with 250 ppm zinc ion would provide 25% of the adult recommended dietary allowance of zinc.
Depolymerization of the Glutenin Macropolymer During Dough Mixing: I. Changes in Levels, Molecular Weight Distribution, and Overall Composition
Authors: Skerritt John H. , Hac Luch , Bekes Ferenc
Published: June 2007

Changes in the amounts, molecular weight distributions, and levels of major groups of subunits in the glutenin macropolymer (GMP) of doughs during mixing were investigated. The GMP (gel protein) is the unreduced fraction of gluten protein that remains as a layer on top of the starch after extraction of SDS‐soluble proteins and centrifugation. Experiments involved doughs prepared from flours derived from one weak and one strong cultivar and lines derived from cv. Olympic that were null for specific high molecular weight glutenin subunits (HMW‐GS). During mixing, the amount of GMP decreased; the major changes occurred before peak mixing time (MT, achievement of peak resistance). In addition, the average apparent molecular weight of GMP (determined by both size‐exclusion HPLC and multilayer gel electrophoresis) decreased during mixing, but in this case, the major changes were seen later in the mixing process, during dough breakdown. Even after extensive mixing, polymers and oligomers were released, not free glutenin subunits. During dough breakdown, the composition of GMP also changed, such that the proportion of HMW‐GS decreased but β‐amylases/D low molecular weight glutenin subunits (LMW‐GS) increased. Changes in the total amounts of other LMW‐GS typically were smaller with a decrease in the proportion of B subunits and an increase in the proportion of C subunits. The major changes in GMP composition were observed after peak MT (peak resistance) occurring earlier and to a greater extent in the weaker dough. Our results suggest that dough breakdown during mixing may be triggered by loss of HMW‐GS, leading to changes in the molecular weight distribution and composition of the disulfide‐bonded GMP.
Depolymerization of the Glutenin Macropolymer During Mixing: II. Differences in Retention of Specific Glutenin Subunits
Authors: Skerritt John H. , Hac Luch , Lindsay Megan P. , Bekes Ferenc
Published: June 2007

The depolymerization of individual high and low molecular weight (HMW and LMW, respectively) glutenin subunits (GS) from the glutenin macropolymer (GMP) in doughs during mixing was investigated by reversed‐phase (RP) HPLC and SDS‐PAGE. Cultivars with different dough strengths, as well as lines null for specific HMW‐GS and biotypes differing at individual HMW‐GS and LMW‐GS encoding loci, were studied. During mixing, the proportion of total HMW‐GS in GMP decreased, and the ratios of different subunits in the GMP in doughs changed. There was a loss of chromosome 1B‐ and 1D‐encoded x‐HMW‐GS, while the relative proportions of y‐HMW‐GS (among HMW‐GS) increased. Changes in 1B subunits occurred first, while most of the changes in 1D HMW‐GS content occurred during dough breakdown. Changes were more pronounced for doughs of weak to average strengths than for stronger doughs. RP‐HPLC analysis demonstrated a consistent increase in the retention times (surface hydrophobicity) of chromosome 1D‐encoded HMW‐GS but not of other HMW‐GS or LMW‐GS during mixing. SDS‐PAGE and RP‐HPLC demonstrated that specific B subunits, typically those with lower hydrophobicity, were selectively depolymerized from the GMP during dough breakdown, while the proportions of specific C subunits, typically those with greater hydrophobicity, increased. Similar trends were seen in analyses of several pairs of biotypes differing at single LMW‐GS encoding loci, although there were slight differences in the depolymerization behavior of wheats with different allelic compositions. The results suggest that dough breakdown may be triggered by the loss of specific HMW‐GS from the GMP, and a structural hierarchy may exist for different LMW‐GS within glutenin in doughs.
Comparison of Yield and Composition of Oil Extracted from Corn Fiber and Corn Bran
Authors: Moreau Robert A. , Singh Vijay , Eckhoff Steven R. , Powell Michael J. , Hicks Kevin B. , Norton Robert A.
Published: June 2007

We recently reported that corn fiber oil contains high levels of three potential cholesterol‐lowering phytosterol components: ferulate‐phytosterol esters (FPE) (3–6 wt%), free phytosterols (1–2 wt%), and phytosterol‐fatty acyl esters (7–9 wt%). A previous study also indicated that corn bran oil contained less phytosterol components than corn fiber oil. The current study was undertaken to attempt to confirm this preliminary observation using more defined conditions. Accordingly, oil was extracted from corn fiber and corn bran prepared under controlled laboratory conditions, using the same sample of corn hybrid kernels for each, and using recognized bench‐scale wet‐milling, and dry‐milling procedures, respectively. After extraction, the chemical composition of the phytosterol components in the oil were measured. This study confirmed our previous observation—that FPE levels were higher in corn fiber oil than in corn bran oil. During industrial wet‐milling, almost all of the FPE are recovered in the fiber fraction (which contains both fine and coarse fiber). During laboratory‐scale wet‐milling, ≈60–70% of the FPE are recovered in the coarse fiber (pericarp) and 30–40% are recovered in the fine fiber. During laboratory‐scale dry‐milling, <20% of the FPE are recovered in the bran (pericarp), and the rest in the grits. The recoveries of the other two phytosterol components (free phytosterols and phytosterol‐fatty acyl esters) revealed a more complex distribution, with significant levels found in several of the dry‐ and wet‐milled products.
Viscosity Concerns with Rye Mashes Used for Ethanol Production
Authors: Ingledew W. M. , Thomas K. C. , Hynes S. H. , McLeod J. G.
Published: June 2007

Rye cultivars leading to high‐viscosity extracts were easily mashed— even under very high gravity (VHG) conditions—when enzymes were added to reduce viscosity caused by pentosans. The enzymes were so effective that for the fuel alcohol industry, the need for special genetic selections of rye with reduced extract viscosity was not indicated. High‐starch cultivars of rye, however, were still most beneficial when alcohol was the end product of value. Both normal and VHG mashes fermented out within 48 hr under the conditions described. Yields (L/t of starch) were, on average, 5.3% higher under VHG conditions than under normal gravity.
Effects of Mixing Conditions and Wheat Flour Dough Composition on Lipid Hydrolysis and Oxidation Levels in the Presence of Exogenous Lipase
Authors: Castello Philippe , Potus Jacques , Baret Jean‐Luc , Nicolas Jacques
Published: June 2007

The lipid profiles of wheat flour doughs containing exogenous lipase were studied under different mixing conditions using a microscale mixer. An experimental design comparing the effects of dough water content (52–68%), the speed of mixing (50–100 rpm), and the mixer temperature (18–32°C) showed that the hydrolysis levels were positively influenced by temperature and speed of mixing and negatively influenced by water content. The positive effect of temperature was enhanced both by highspeed mixing and low water content. The lipid oxidation levels were positively influenced by the speed of mixing and negatively influenced by the water content. The positive effect of temperature on the oxidation levels was less important. A series of experiments conducted with different types of industrial and semi‐industrial mixers with equal concentrations of lipase added to the dough showed large differences among the rates of lipid hydrolysis and oxidation. However, the mixing conditions proposed by bakers to obtain doughs with similar handling properties led to similar dough lipid profiles. Sodium chloride did not change the lipid profile when added to dough. Conversely, calcium chloride promoted a large increase of lipid hydrolysis and oxidation due to its activation of lipase activity. Addition of yeast increased the lipid hydrolysis and slightly decreased lipid oxidation.
Properties and Composition of Turkish Flat Bread (Bazlama) Supplemented with Barley Flour and Wheat Bran
Authors: Başman Arzu , Köksel Hamit
Published: June 2007

In this study, effects of increasing levels of wheat bran and barley flour on dough properties and bazlama quality were investigated. Bazlama is a flat bread commonly consumed in Turkey. Flours of wheat cultivars Gün and Gerek, flour of barley cultivar Tokak, and Gerek bran mixture were used. Part of the wheat flours were replaced with barley flour at 10, 20, 30, and 40% levels and Gerek bran mixture at 5, 10, 15, and 20% levels. Farinogram properties of mixtures were determined. Bazlama samples were subjected to sensory analysis for external appearance, shape and symmetry, crust color, crumb color and structure, mouthfeel, taste and aroma. Increasing levels of bran and barley flour caused decreases in all sensory properties. The deteriorative effect of barley flour on bazlama properties was generally more obvious when compared to bran supplementation. However, all bazlama samples were considered acceptable. Penetrometer values of bazlama samples showed that increasing levels of barley flour created significantly softer bazlama. However, in bran‐supplemented bazlama samples, effect of bran on softness was found to be insignificant in both cultivars. Bazlama samples supplemented with bran had lower L values and higher a and b values for color when compared to those supplemented with barley flour. In all samples, effect of increasing levels of barley flour on residual β‐glucan was found to be insignificant in both cultivars. Acid detergent fiber and neutral detergent fiber values increased with increasing levels of bran, and the changes in both cultivars were similar.
Aroma of Cooked Rice (Oryza sativa): Comparison Between Commercial Basmati and Italian Line B5‐3
Authors: Tava Aldo , Bocchi Stefano
Published: June 2007

Selected lines of aromatic rice from American cv. A301 were cultivated in Italy, and the agronomic traits and chemical properties related to their aroma were studied. The most characteristic compound responsible for aromatic rice, 2‐acetyl‐1‐pyrroline, was quantified in all lines. Line B5‐3, characterized by high 2‐acetyl‐1‐pyrroline content, was investigated in greater detail for its volatile components and was compared with a commercial Basmati rice. Volatiles were collected by steam‐distillation. Several classes of compounds were identified and quantified in both samples, including hydrocarbons, aldehydes, alcohols, ketones, heterocyclic, terpenes, disulfides, and phenols. Hexanal was the most abundant compound in both samples, followed by pentanal, 2‐acetyl‐1‐pyrroline, hexanol, benzaldehyde, oct‐1‐en‐3‐ol, 4‐vinylguaiacol, indole, and trans‐2‐ nonenal. 2‐Acetyl‐1‐pyrroline was present at 570 and 2,350 ppb in Basmati and B5‐3, respectively.
Effects of Mixing Conditions on Pasta Dough Development and Biochemical Changes
Authors: Icard‐Vernière Christèle , Feillet Pierre
Published: June 2007

Mixing of commercial durum wheat semolina with water was performed under different conditions in a Brabender micromixer equipped with pastamaking shafts. Semolina filling of the mixing chamber was 30.4–42.9% (v/v), shaft speed was 10–110 rpm, temperature was 10–40°C, and hydration level was 47–52.5% (db). The blend of water and semolina evolved from individualized hydrated particles (HP) to a dough product (DP) as a function of these conditions. Torque values (T) and the specific mechanical energies (SME) were recorded during mixing as a function of time. Terms from these curves were defined to characterize the mixing process: to (starting time of dough development), td (time to reach the maximum dough consistency), Tm (mean torque value after dough development), and SMEf (total energy applied to the dough during mixing). Transformation of HP into DP and the mixing temperature were the main parameters affecting to, td, Tm, and SMEf. Protein aggregate distribution was measured by size‐exclusion HPLC, protein solubility in 0.01N acetic acid, free ‐SH content, soluble arabinoxylans, reducing sugars, ferulic acid, carotenoid content, and oxidase activities to characterize the biochemical changes that occurred during pasta dough formation. DP was characterized by lower amounts of insoluble glutenin aggregates, lower protein solubility in dilute acetic acid, lower free ‐SH content, ferulic acid, carotenoid content, and lower oxidoreductase activities as compared to HP. Once the dough was developed, the effects of mixing speed, temperature, or hydration level on the biochemical composition of the blend were null or low compared to the modifications that were observed when the blends changed from HP to DP. The to and SMEf were the most significant parameters in characterizing the pasta dough mixing process in relation to biochemical changes.
The Potential of Hull‐less Barley
Authors: Bhatty R. S.
Published: June 2007

Hull‐less barley (HB) has been investigated in many countries for use in feed, food, and industry since the publication of the last review in 1986. Literature published since 1990 on various aspects of HB utilization, other than in monogastric feeds, has been reviewed. Several HB cultivars containing low or β‐glucan, low or high extract viscosity, and waxy (0–5% amylose) or normal starch are now available. Interest in HB utilization in the food industry developed largely due to its high β‐glucan content, particularly in the waxy cultivars. β‐Glucan is a major component of soluble fiber implicated in hypocholesterolemia, hypoglycemia, and in reducing incidence of chemically induced colon cancer in experimental animals. However, large‐scale clinical trials using human subjects are needed to corroborate these effects. The zero amylose HB starch had low syneresis or a high freeze‐thaw stability suitable for use in frozen foods. Single‐ or double‐modified waxy HB starch may replace corn starch in some food applications, and cationized HB starch can replace corn and potato starches in the pulp and paper industry. HB may be milled using conventional wheat milling equipment to yield bran and flour for multiple food uses. Hull‐less barley may also be used as a feed stock for fuel alcohol production, for the preparation of food malt with low or high enzyme activities, and for brewer's and distiller's malts.
Effects of Corn Sample, Mill Type, and Particle Size on Corn Curl and Pet Food Extrudates
Authors: Mathew J. M. , Hoseney R. C. , Faubion J. M.
Published: June 2007

The effects of corn sample, grinder type, and particle size of ground corn on the extrusion of corn curls and pet food were studied. Extrusion runs were conducted using a twin‐screw extruder. Properties of corn curl and pet food extrudates were affected significantly by corn samples obtained from different parts of the country (Nebraska, Illinois, and Texas), even though grinding and extrusion parameters were held constant. The type of grinder used to grind the corn had an effect on extrusion properties. The volumetric expansion index (VEI) of extrudate from pin‐milled samples was lower than that of extrudate from the same corn ground in a hammer mill or roller mill. Small particle size, obtained by grinding corn in a hammer mill with different screen sizes, produced extrudate with a significantly higher VEI than extrudate from coarse‐ or medium‐sized particles.
Effects of Amylopectin Branch Chain Length and Amylose Content on the Gelatinization and Pasting Properties of Starch
Authors: Jane J. , Chen Y. Y. , Lee L. F. , McPherson A. E. , Wong K. S. , Radosavljevic M. , Kasemsuwan T.
Published: June 2007

Structures and properties of starches isolated from different botanical sources were investigated. Apparent and absolute amylose contents of starches were determined by measuring the iodine affinity of defatted whole starch and of fractionated and purified amylopectin. Branch chain‐length distributions of amylopectins were analyzed quantitatively using a high‐performance anion‐exchange chromatography system equipped with a postcolumn enzyme reactor and a pulsed amperometric detector. Thermal and pasting properties were measured using differential scanning calorimetry and a rapid viscoanalyzer, respectively. Absolute amylose contents of most of the starches studied were lower than their apparent amylose contents. This difference correlated with the number of very long branch chains of amylopectin. Studies of amylopectin structures showed that each starch had a distinct branch chain‐length distribution profile. Average degrees of polymerization (dp) of amylopectin branch chain length ranged from 18.8 for waxy rice to 30.7 for high‐amylose maize VII. Compared with X‐ray A‐type starches, B‐type starches had longer chains. A shoulder of dp 18–21 (chain length of 6.3–7.4 nm) was found in many starches; the chain length of 6.3–7.4 nm was in the proximity of the length of the amylopectin crystalline region. Starches with short average amylopectin branch chain lengths (e.g., waxy rice and sweet rice starch), with large proportions of short branch chains (dp 11–16) relative to the shoulder of dp 18–21 (e.g., wheat and barley starch), and with high starch phosphate monoester content (e.g., potato starch) displayed low gelatinization temperatures. Amylose contents and amylopectin branch chain‐length distributions predominantly affected the pasting properties of starch.
Development of a Field Enzyme‐Linked Immunosorbent Assay (ELISA) for Detection of α‐Amylase in Preharvest‐Sprouted Wheat
Authors: Verity J. Christiana K. , Hac Luch , Skerritt John H.
Published: June 2007

A sandwich enzyme‐linked immunosorbent assay (ELISA) has been developed for detection of α‐amylase in preharvest sprouted wheat and adapted to rapid field‐use formats requiring 15–20 min to perform. Polyclonal and monoclonal antibodies were prepared to detect a mixture of high and low pI isozymes of α‐amylase and high pI isozymes only. All antibodies detected α‐amylase on immunoblots of either a crude wheat extract or of purified enzyme, but only the polyclonal antibodies functioned in a sandwich ELISA. Depending on the antibody combination, the tube ELISA detected either the high and low pI isozymes of α‐amylase or the high pI isozymes only with a detection limit of ≈0.5–1.0 ng/mL of amylase. Wheats with falling numbers (FN) of <350 sec could be discriminated from sound wheats, with decreasing FN producing increasing assay color. Using 130 wheat grain samples, ELISA absorbances for detection of both high and low pI isozymes and of high pI isozymes only were highly positively correlated with amylase enzyme activity and negatively correlated with FN. The correlations were similar for detection of both isozyme families and for detection of high pI isozymes only. Analyses of three sets of wheat samples from different environments demonstrated that the relationship between ELISA absorbance and FN had little dependence on wheat cultivar. The precision of sample analysis using the field ELISA was similar to the precision of FN test apparatus.
Demixing in Wheat Doughs—Its Influence on Dough and Gluten Rheology
Authors: Kieffer R. , Stein N.
Published: June 2007

Reshaping of relaxed wheat doughs leads to an increase in firmness that significantly changes the results of rheological measurements involving large uniaxial deformations of the dough, whereas the gluten properties remain unaffected. Microscopic investigations reveal that directly after kneading, starch and gluten are thoroughly mixed. However, the shaping procedure of a relaxed dough or shear‐flow during rheological measurements cause a separation of gluten and starch. The dilatant behavior of the starch granules and the capacity of gluten to aggregate account for the observed dough‐hardening.
Protein Changes During Various Stages of Breadmaking of Four Spring Wheats: Quantification by Size‐Exclusion HPLC
Authors: Borneo Rafael , Khan Khalil
Published: June 2007

Protein changes for four hard red spring wheat genotypes (Len, Marshall, 215, and Butte 86) were assessed at various stages of breadmaking using a size‐exclusion HPLC technique. Breadmaking stages considered were flour, after mixing, before punching, after punching, after fermentation, and after proofing. Quality and functional characteristics of the four wheat genotypes were determined. The three main protein groups isolated by SE‐HPLC were further characterized by SDS‐PAGE. A direct relationship between polymeric glutenin (peak I of SE‐HPLC fractions) in flours and loaf volume was found for the three wheat genotypes with identical high molecular weight glutenin subunit (HMW‐GS) composition (2*, 7+9, 5+10) and one line with similar HMW‐GS composition (2*, 7+9, 2+12), differing in the Glu‐D1 locus. Quantitative changes in the distribution of SDS‐soluble proteins fractionated by SE‐HPLC were also examined. Peak I proteins (polymeric proteins) from SDS‐extractable proteins tend to decrease during breadmaking, while peak III proteins (low molecular weight) tend to increase. Peak II (monomeric proteins, medium molecular weight) did not show a change in quantity during breadmaking. These results seem to indicate that some type of rearrangement took place during the breadmaking process to release proteins of smaller molecular weight.
Extrusion Chemistry of Wheat Flour Proteins: I. Free Radical Formation
Authors: Schaich K. M. , Rebello C. A.
Published: June 2007

Electron paramagnetic resonance (EPR) spectroscopy was used to study free radical production in hard red wheat flours extruded according to a two‐level fractional factorial experimental design (11 and 14% protein content, 160 and 185°C, 16 and 20% moisture, 300 and 500 rpm screw speed, and mass flow rate of 225 and 400 g/min). All spectra showed dominant broad singlets (g = 2.0053–2.0059) from nitrogen‐centered radicals originating from heat‐induced peptide scission and reactions of lipid radicals with side‐chain amino groups. At 77 K, sulfur‐oxyl or peroxyl radicals (g = 2.008–2.018), thiyl radicals (g = 2.025), and disulfide radical species (g = 2.032–2.035 and 2.05–2.06), resulting from intra‐ and intermolecular electron migration and shear‐induced scission of disulfides, sometimes were present. The strongest EPR signals occurred under conditions of maximum free radical production and minimum opportunity for radical recombination: high protein flour (14%), high die temperature (180°C), and low moisture (16%). EPR signals correlated with sulfhydryl and disulfide (SH‐SS) levels and physical properties of extrudates, indicating that free radicals are integrally involved in molecular changes that occur during extrusion.
Effect of Chemical Pretreatments and Lactic Acid on the Rate of Water Absorption and Starch Yield in Corn Wet‐Milling
Authors: Haros M. , Suárez C.
Published: June 2007

The relative effectiveness of dehulling, potassium hydroxide dipping (alkali concentrations 0.2, 0.5, and 1.0 %), and ethyl oleate spraying (aqueous emulsion 1%, v/v) to increase the rate of water absorption by dent and flint corn during steeping was compared with untreated corn samples. These pretreatments increased the water absorption rate of both hybrids when compared with the untreated control samples. To evaluate the observed increase, the diffusion coefficients of pretreated and untreated corn samples were estimated. Corn grains steeped in SO2 aqueous solution and variable lactic acid concentrations (0.2, 0.5, and 1.0%, v/v) were performed. Absorption rates for lactic acid concentrations were ≈0.5% higher than those steeped only in SO2 solution. This effect was more marked for dent than for flint corn. Corn samples pretreated with potassium hydroxide had lower starch yields than the control. However, the presence of lactic acid in steepwater increased the starch yield of dent and flint corn, particularly for the samples treated with alkaline solution. This procedure was particularly beneficial for flint corn. An effective release of the starch granules was achieved within 24 hr of steeping.