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1.
Molecular weight distribution (MWD) of proteins extracted from hard red spring wheat was analyzed by size‐exclusion HPLC to investigate associations with wheat and breadmaking quality characteristics. Certain protein fractions were related to associations between wheat and breadmaking parameters, specifically when effect of quantitative variation of protein on those parameters was statistically eliminated by partial correlation analysis. SDS‐unextractable high molecular weight polymeric proteins had positive partial correlations with percent vitreous kernel content and breadmaking parameters, including mix time and bread loaf volume. SDS‐extractable protein fractions that were eluted before the primary gliadin peak had positive partial correlations with kernel hardness and water absorption parameters. The proportion of main gliadin fractions in total protein had a negative partial correlation with bread loaf volume and positive correlations with kernel hardness and water absorption parameters. Intrasample uniformity in protein MWD and kernel characteristics was estimated from three kernel subsamples that were separated according to single kernel protein content within individual wheat samples by a single‐kernel near‐infrared sorter. Wheat subsamples were significantly different in protein MWD. Intrasample uniformity in protein MWD did not differ greatly among wheat samples.  相似文献   

2.
A Bacillus subtilis endoxylanase (XBS) with a strong selectivity for hydrolysis of water‐unextractable arabinoxylan (WU‐AX) and an Aspergillus aculeatus endoxylanase (XAA) with a strong selectivity for hydrolysis of water‐extractable arabinoxylan (WE‐AX) were used in straight‐dough breadmaking with two European wheat flours. Dough, fermented dough, and bread characteristics with different levels of enzyme addition were evaluated with a strong emphasis on the arabinoxylan (AX) population. The WU‐AX solubilized by XBS during breadmaking were mainly released during mixing and had higher molecular weight, in contrast to their counterparts solubilized by XAA, which were mainly released during fermentation and had lower molecular weight. This coincided with increased loaf volume with XBS and a negative to positive loaf volume response with XAA. Bread firmness and dough extract viscosity also were affected by endoxylanase addition. Results confirmed that WU‐AX are detrimental for breadmaking, while WE‐AX and solubilized AX with medium to high molecular weight have a positive impact on loaf volume.  相似文献   

3.
This research aims to investigate the relationship between the solvent retention capacity (SRC) test and quality assessment of hard red spring (HRS) wheat flour samples obtained from 10 HRS cultivars grown at six locations in North Dakota. The SRC values were significantly (P < 0.05) correlated with flour chemical components (protein, gluten, starch, and damaged starch contents, except arabinoxylan); with farinograph parameters (stability [FST], water absorption, peak time [FPT], and quality number); and with breadmaking parameters (baking water absorption [BWA], bread loaf volume [BLV], and symmetry). Differences in locations and cultivars contributed significantly to variation in quality parameters and SRC values. Suitability of SRC parameters for discriminatory analysis of HRS wheat flour is greatly influenced by molecular weight distribution (MWD) of SDS‐unextractable proteins. SRC parameters, except for sucrose SRC, showed significant (P < 0.01) and positive correlations with high‐molecular‐weight (HMW) polymeric proteins in SDS‐unextractable fractions, whereas only lactic acid SRC exhibited significant (P < 0.01) correlations with low‐molecular‐weight polymeric proteins. HMW polymeric proteins also exhibited positive associations with FPT, FST, BWA, and BLV. The discrepant variation in association of SRC parameters with respect to MWD of SDS‐unextractable proteins could improve segregation of HRS wheat flour samples for quality.  相似文献   

4.
In the present study, we evaluated 444 organically grown wheat genotypes for the amount and size distribution of polymeric proteins by size‐exclusion HPLC. The investigated genotypes were divided into six genotype groups—selection, spelt, old cultivar, primitive, landrace, and cultivar—and these were grown in four different locations, namely, Alnarp, Bohuslän, Gotland, and Uppsala in Sweden. The results showed that the percentage of unextractable polymeric proteins in total polymeric proteins (%UPP) and percentage of large unextractable polymeric proteins in total polymeric proteins were higher in the cultivar group as compared with the rest of the investigated genotype groups. The amounts of total extractable polymeric proteins (TOTE) and total unextractable polymeric proteins were low in cultivars and selections, respectively. Spring wheat grain was found to have a significantly higher amount of all protein fractions as compared with winter wheat. The genotype Kenya was found to belong to both groups of the 20 genotypes with the highest TOTE and %UPP. Thus, the genotype Kenya might be of relevance for consumption and future breeding to improve the breadmaking quality of organically produced wheat.  相似文献   

5.
The aim of this study was to analyze sulfur content, protein size distribution, and free amino acids in flour mill streams (FMS) and their associations to dough rheology and breadmaking traits. Break FMS had higher nitrogen and sulfur quantities than reduction FMS. The third break FMS had the highest nitrogen and sulfur contents among FMS but low bread loaf volume partly due to high ash content. Sulfur quantity had greater or equivalent correlations with dough rheology and breadmaking properties compared with nitrogen quantity when the effect of percent ash content was removed statistically. FMS also showed significant quantitative variation in HMW polymeric proteins of the SDS‐unextractable fraction that had greater association with sulfur content and dough rheology and breadmaking traits than other protein fractions. Asparagine, which is a major amino acid in flour, was found at higher levels in the third break and third reduction FMS. Ratio of nitrogen to sulfur was significantly correlated with asparagine concentration (r = 0.73, α = 0.01). This study indicates that information on sulfur, protein size distribution, and free amino acid is potentially useful in research for more precise blending of FMS in commercial flour mills to meet customer specifications for high quality flour.  相似文献   

6.
The objective of this study was to investigate whether a narrow‐bore column (NBC) (300 × 4.5 mm, i.d.) improved analyses of unreduced proteins in flour by size‐exclusion HPLC (SE‐HPLC) and subsequent evaluation of breadmaking quality of hard spring wheat flours. Total protein extracts and SDS buffer extractable and unextractable proteins were analyzed by SE‐HPLC. NBC separated proteins in 10 min at a flow rate of 0.5 mL/min with similar resolution to a regular column (300 × 7.8 mm, i.d.) which took 30 min. SE‐HPLC absorbance area (AA) data obtained from an NBC showed comparable or superior repeatability and correlations with flour breadmaking characteristics when compared with those of a regular column. AA values of total protein that were calculated by adding AA values of SDS extractable and unextractable proteins showed greater repeatability and correlations with quality characteristics than those of actual total protein extracts. The improvements including employment of an NBC in SE‐HPLC provide enhancement of rapid quality evaluation and decreased consumption of hazardous organic solvents.  相似文献   

7.
Thirteen hard red spring wheat genotypes in which seven genotypes had the same high molecular weight (HMW) glutenin subunits (2*, 7+9, 5+10) were compared for their physical-chemical and breadmaking properties. These samples were categorized into three groups based on their dough mixing and baking performances as follows: the strong dough (SD) group (six genotypes), characterized by the strongest dough mixing (average stability, 35 min); the good loaf (GL) group (four genotypes), characterized by the largest loaf volume; and the poor loaf (PL) group (three genotypes), characterized by the smallest loaf volume. Total flour proteins were fractionated into 0.5M salt-soluble proteins, 2% SDS-soluble proteins, and residue proteins (insoluble in SDS buffer). SDS-soluble proteins, residue proteins, and total flour proteins were analyzed by SDS-PAGE and densitometry procedures to determine the proportions of HMW glutenin subunits, medium molecular weight proteins, and low molecular weight proteins in relation to the total amount of proteins. No differences in the amount of salt-soluble proteins were found among the different groups of samples. Solubilities of gluten proteins (total proteins minus salt-soluble proteins) in SDS buffer were related to the differences in dough strength and baking quality among the three groups. The SD group had the lowest solubility and the PL group had the highest. SDS-PAGE analysis showed that SDS-soluble proteins of the SD group contained a smaller amount of HMW glutenin subunits than those of the GL and PL groups. The highest proportions of HMW glutenin subunits in total flour proteins were found in the SD group, while the PL group had the lowest percentage of HMW glutenin subunits in their total flour proteins. These results showed that the total quantities of HMW glutenin subunits played an important role in determining the dough mixing strength and breadmaking performance of hard red spring wheats.  相似文献   

8.
Nitrogen (N) and sulfur (S) supplies have a strong influence on the quality and quantity of wheat storage proteins, which play an important role in the breadmaking process. Nitrogen derived from urea, S from micronized elemental sulfur, and a mixture of both (N+S) were applied at anthesis stage on wheat by foliar spray. To relate N and S incorporation in storage proteins to the quality of dough, their incorporation into each storage protein fraction was measured: monomers, low molecular weight glutenin subunits (LMW‐GS), and high molecular weight glutenin subunits (HMW‐GS). Then protein fraction quantities, molecular weight distribution (MWD), polymerization index (PI), and molecular dimensions of unextractable polymeric protein (UPP), as well as dough mixing properties were determined. Fertilizers N and S were differentially incorporated into each storage protein fraction, influencing protein synthesis. Moreover, after the N+S fertilization, the increase of the polymeric proteins induced an increase in molecular weight and compactness, as well as in dough strength and consistency. These results provide evidence that N and S fertilizers applied by foliar spray route at anthesis, simultaneously, play an important role in controlling the storage protein synthesis and the degree of polymerization, which in turn influence dough mixing properties.  相似文献   

9.
This research was initiated to investigate associations between flour breadmaking traits and mixing and empirical dough rheological properties under thermal stress. Thirty hard spring wheat flour samples were analyzed by a Mixolab standard procedure. Mixolab profiles were divided into six different stages, and torque measurements of individual stages were modeled by nonlinear curve fitting using a compound of two solution searching procedures, multidimensional unconstrained nonlinear minimization and genetic algorithm. Mixing patterns followed exponential equations. Dough torque patterns under heat constraint, specifically dough thermal weakening and pasting profiles, were described by a sigmoid logistic equation as a function of time. Dough stability during heating appeared important for bread loaf volume increase from significant correlations between bread loaf volume and parameters generated from models of a dough thermal weakening stage. Multivariate continuum regression was employed to calibrate prediction models of baking traits using Mixolab parameters. Coefficients of determination estimated from prediction models and cross‐validation were greater than 0.98 for bake water absorption, mixing time, and bread loaf volume, indicating that the Mixolab parameters have a potential to enhance evaluation of flour breadmaking quality.  相似文献   

10.
Dough extensibility affects processing ease, gas retention, and loaf volume of finished products. The Kieffer dough extensibility test was developed to assess extensibility of small dough samples and is therefore adapted for use in breeding programs. Information is lacking on relationships between wheat growing environments and dough properties measured by the Kieffer dough extensibility test. This study documents the variability of dough extensibility (Ext), maximum resistance to extension (Rmax), and area under the extensibility curve (Area) in relation to breadmaking quality, and the effect of wheat growing environments. Mixograph, Kieffer dough extensibility, and bake tests were performed on flour milled from 19 hard red spring wheat (Triticum aestivum L.) genotypes grown during three growing seasons (2007‐2009) at six South Dakota locations. Although both genotype and environment had significant effects on Kieffer dough extensibility variables, environment represented the largest source of variation. Among genotype means, Area was most correlated (r = 0.63) with loaf volume, suggesting that by selecting lines with increased Area, loaf volume should improve. Rmax was positively correlated (r = 0.58) with loaf volume among genotype means but negatively correlated (r = –0.80) among environmental means. Ext was positively correlated (r = 0.90) with loaf volume among environmental means. Weather variables were correlated with Rmax, Ext and loaf volume and therefore could help predict end‐use quality.  相似文献   

11.
The objectives of this study were to assess how functional properties of proteins in whole meal wheat (Triticum aestivum L.) flour vary across different growth environments. Grain from three commercial Australian Hard milling wheat cultivars was analyzed from four growth locations in 2008 and from two of the corresponding cultivars and locations in 2009. The protein content of the grain, soluble and insoluble extractable protein fractions, swelling index of glutenin (SIG), glutenin‐to‐gliadin ratio (Glu:Gli), percent unextractable polymeric protein (%UPP), and dough properties including force at maximum resistance (Rmax) and extensibility were measured. Based on analysis of variance of aggregated data for the cultivars, growth locations, and seasons, growth environment factors made significant contributions to variability in the total grain protein, Glu:Gli ratio, %UPP, SIG, Rmax, and extensibility of the wheat flour. Variability of protein content of the soluble and insoluble extractable protein fractions was mostly owing to genotype.  相似文献   

12.
Twenty‐seven durum wheat genotypes originating from different geographical areas, all expressing LMW‐2 at Glu‐B3, and five bread wheats were evaluated for flour mixing properties, dough physical characteristics, and baking performance. Gluten polymeric composition was studied using size‐exclusion HPLC of unreduced flour protein extracts. As a group, durum wheats had poorer baking quality than bread wheats in spite of higher protein and total polymer concentrations. Durum wheats exhibited weaker gluten characteristics, which could generally be attributed to a reduced proportion of SDS‐unextractable polymer, and produced less extensible doughs than did bread wheats. However, substantial variation in breadmaking quality attributes was observed among durum genotypes. Better baking performance was generally associated with greater dough extensibility and protein content, but not with gluten strength related parameters. Extensibility did not correlate with gluten strength or SEHPLC parameters. Genotypes expressing high molecular weight glutenin subunits (HMW‐GS) 6+8 exhibited better overall breadmaking quality compared with those expressing HMW‐GS 7+8 or 20. Whereas differences between genotypes expressing HMW‐GS 6+8 and those carrying HMW‐GS 7+8 could only be attributed to variations in extensibility, the generally inferior baking performance of the HMW‐GS 20 group relative to the HMW‐GS 6+8 group could be attributed to both weaker and less extensible gluten characteristics.  相似文献   

13.
The objective of this study was to evaluate protein composition and its effects on flour quality and physical dough test parameters using waxy wheat near‐isogenic lines. Partial waxy (single and double nulls) and waxy (null at all three waxy loci, Wx‐A1, Wx‐B1, and Wx‐D1) lines of N11 set (bread wheat) and Svevo (durum) were investigated. For protein composition, waxy wheats in this study had relatively lower albumins‐globulins than the hard winter wheat control. In the bread wheats (N11), dough strength as measured by mixograph peak dough development time (MDDT) (r = 0.75) and maximum resistance (Rmax) (r = 0.70) was significantly correlated with unextractable polymeric protein (UPP), whereas in durum wheats, moderate correlation was observed (r = 0.73 and 0.59, respectively). This may be due to the presence of high molecular weight glutenin subunits (HMW‐GS) Dx2+Dy12 at the Glu‐D1 locus instead of Dx5+Dy10, which are associated with dough strength. Significant correlation of initial loaf volume (ILV) to flour polymeric protein (FPP) (r = 0.75) and flour protein (FP) (r = 0.63) was found in bread wheats, whereas in durum wheats, a weak correlation of ILV was observed with FP (r = 0.09) and FPP (r =0.51). Significant correlation of ILV with FPP in bread wheats and with % polymeric protein (PPP) (r = 0.75) in durum lines indicates that this aspect of end‐use functionality is influenced by FPP and PPP, respectively, in these waxy wheat lines. High ILV was observed with 100% waxy wheat flour alone and was not affected by 50% blending with bread wheat flour. However, dark color and poor crumb structure was observed with 100% waxy flour, which was unacceptable to consumers. As the amylopectin content of the starch increases, loaf expansion increases but the crumb structure becomes increasingly unstable and collapses.  相似文献   

14.
Gluten, starch, lipids, and water-soluble material were separated from seven wheat samples with a range of protein contents and breadmaking quality. The isolated glutens were further partitioned into gliadin- and gluteninrich fractions using pH precipitation. Protein content and glutenin-togliadin ratio were systematically altered by blending these fractions into the original flours in calculated amounts. Mixing properties, extension-tester parameters, and baking performance of composite flours were determined using small-scale techniques. Results of dough testing with blends of constant glutenin-to-gliadin ratio showed increases in the mixing time, mixograph peak resistance, maximum resistance to extension, extensibility, and loaf volume as the protein content increased. At constant protein content, increases in glutenin-to-gliadin ratio were associated with increases in mixing time, mixograph peak resistance, maximum resistance to extension, and loaf volume, and with decreases in extensibility. Thus, total protein content and glutenin-to-gliadin ratio independently affected dough and baking properties. The results have allowed the separation of the effects of flour protein quantity and composition on breadmaking properties.  相似文献   

15.
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.  相似文献   

16.
A quick method for the separation of the main size classes of wheat endosperm proteins using size‐exclusion HPLC is presented. Separations achieved in a 10‐min run showed high correlation with the reference method of our laboratory (35‐min) using the same type of column. The clear separation obtained allows a quick analytical determination of important parameters such as the proportion of the main classes of wheat endosperm protein, the glutenin‐to‐gliadin ratio, and the percentage of unextractable (SDS‐soluble with sonication) polymeric protein, all of which have been closely correlated with breadmaking quality parameters. The improved method offers the advantages of better utilization of valuable resources such as HPLC equipment, quicker analysis of large sample sets, and collection of eluted fractions.  相似文献   

17.
Wheat protein quantity and composition are important parameters for wheat baking quality. The objective of this study was to use fractionation techniques to separate the proteins of flour mill streams into various protein fractions, to examine the distribution of these protein fractions, and to establish a relationship between protein composition and breadmaking quality. Nine break streams, nine reduction streams, and three patent flours obtained from three samples of Nekota (a hard red winter wheat) were used in this study. A solution of 0.3M NaI + 7.5% 1-propanol was used to separate flour protein into monomeric and polymeric proteins. The protein fractions, including gliadin, albumin+globulin, HMW-GS, and LMW-GS, were precipitated with 0.1M NH4Ac-MeOH or acetone. The fractions were statistically analyzed for their distribution in the mill streams. The quantities of total flour protein and protein fractions in flour were significantly different among mill streams. The ratio of polymeric to monomeric proteins in break streams was significantly greater than in the reduction streams. The relationship between protein composition and breadmaking quality showed that the quantities of total flour protein, albumin+ globulin, HMW-GS, and LMW-GS in flour were significantly and positively correlated with loaf volume. The ratio of HMW-GS to LMW-GS had little association with loaf volume. The gliadin content in total flour protein was negatively and significantly correlated with loaf volume. These results indicated that the quantity and composition of protein among the mill streams was different, and this resulted in differences in breadmaking quality.  相似文献   

18.
Various whole‐kernel, milling, flour, dough, and breadmaking quality parameters were compared between hard red winter (HRW) and hard red spring (HRS) wheat. From the 50 quality parameters evaluated, values of only nine quality characteristics were found to be similar for both classes. These were test weight, grain moisture content, kernel size, polyphenol oxidase content, average gluten index, insoluble polymeric protein (%), free nonpolar lipids, loaf volume potential, and mixograph tolerance. Some of the quality characteristics that had significantly higher levels in HRS than in HRW wheat samples included grain protein content, grain hardness, most milling and flour quality measurements, most dough physicochemical properties, and most baking characteristics. When HRW and HRS wheat samples were grouped to be within the same wheat protein content range (11.4–15.8%), the average value of many grain and breadmaking quality characteristics were similar for both wheat classes but significant differences still existed. Values that were higher for HRW wheat flour were color b*, free polar lipids content, falling number, and farinograph tolerance. Values that were higher for HRS wheat flour were geometric mean diameter, quantity of insoluble polymeric proteins and gliadins, mixograph mix time, alveograph configuration ratio, dough weight, crumb grain score, and SDS sedimentation volume. This research showed that the grain and flour quality of HRS wheat generally exceeds that of HRW wheat whether or not samples are grouped to include a similar protein content range.  相似文献   

19.
Flours from advanced lines or cultivars of six triticales and two prime hard wheats, along with triticale‐wheat blends, were investigated for mixing, extension (excluding blends), and baking properties using microscale testing. Percentage total polymeric protein (PPP) and percentage unextractable polymeric protein (UPP) of flours and doughs, including blends, mixed to optimal dough development were estimated using size‐exclusion HPLC to determine the changes in protein solubility and association with blend composition (BC), mixing properties, and loaf height. Each triticale was blended with flours of each of the two wheat cultivars (Hartog and Sunco) at 0, 30, 40, 50, 60, 70, and 100% of wheat flour. Nonlinear relationships between BC and mixograph parameters (mixing time [MT], bandwidth at peak resistance [BWPR], and resistance breakdown [RBD]) were observed. A linear relationship between BC and peak resistance (PR) was predominant. PPP of triticale flours was mostly higher than PPP of wheat cultivars. UPP of all triticales was significantly lower than wheat cultivars. PPP of freeze‐dried doughs was mostly nonsignificant across the blends and showed a curvilinear relationship with BC. The deviations from linearity of MT and PPP were higher in triticale‐Sunco blends than in triticale‐Hartog blends. UPP of blends was closer to or lower than the lower component in the blend. The deviations from linearity for MT and UPP were greater in triticale‐Hartog blends than triticale‐Sunco blends. A highly significant correlation (P < 0.001) was observed between BWPR and loaf height. This suggested that BWPR in triticale‐wheat flour blends could be successfully used for the prediction of loaf height. Triticale flour could be substituted for wheat flour up to 50% in the blend without drastically affecting bread quality. Dough properties of triticale‐wheat flour blends were highly cultivar specific and dependent on blend composition. This strongly suggested that any flour blend must be tested at the desired blend composition.  相似文献   

20.
Introduction of high molecular weight glutenin subunits (HMW‐GS) from the Glu‐D1d locus of wheat into triticale restores the genetic constitution of high molecular weight glutenin loci to that of wheat and subsequently improves the breadmaking quality of triticale. One means of achieving such restoration of the genetic constitution is through the use of translocation lines. The aim of this study was to evaluate and compare the performance of translocations 1A.1D and 1R.1D with HMW‐GS 5+10 and 2+12 in terms of physical dough tests and baking quality using four different sets of triticale lines, GDS7, Trim, Rhino, and Rigel. In general, significantly lower milling quality (flour yield), very low mixing times with lower loaf volume were typical of all the triticales studied except 1A.1D 5+10 lines, when compared to hard wheat flour (Pegaso). Among the lines studied, significantly higher loaf volume, mixograph dough development time (MDDT), and maximum resistance to extension (Rmax) were observed with 1A.1D 5+10 lines indicating that translocation of the Glu‐D1d allele with HMW‐GS 5+10 was beneficial in terms of improving the quality attributes. Although pure triticale flour from these lines did not possess the functional characteristics for good quality bread, the translocation 1A.1D that contains HMW glutenin subunits 5+10 showed significant improvement in quality characteristics, and could reasonably be expected to yield commercially satisfactory bread loaves when combined with bread wheat flour. Significantly higher UPP, Rmax, and MDDT values along with a lower gliadin‐to‐glutenin ratio in 1A.1D 5+10 of GDS7 and Rigel sets indicate that the molecular weight distribution was shifted to higher molecular weights, resulting in greater dough strength associated with 5+10 subunits.  相似文献   

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