Description of batter mixing using near infrared spectroscopy

The aim of the present study was to describe the physicochemical events occurring during batter mixing at different water contents (51.8, 54.4, and 56.7 g of water/100 g of dough) using near infrared (NIR) spectroscopy. An FT-NIR spectrometer over the 1000–2500 nm range with a fibre optic probe was used to record NIR spectra in-line. The analysis of both one-dimensional statistical method (principal components analysis) and two-dimensional statistical methods (generalised two-dimensional correlation spectroscopy) was conducted to evaluate the possibilities of NIR spectroscopy to monitor physical and physicochemical modifications observed during mixing of batter. The NIR results were in agreement with the physical and physicochemical analysis traditionally used to study bread dough mixing (consistency and glutenin depolymerisation). PCA on raw NIR spectra demonstrated that PC₁ describes the same traces as the dough consistency curves. PCA on raw NIR spectra can be used to monitor the batter mixing and to identify the NIR mixing time close to the t_peak.PCA on spectra after second derivative demonstrated that PC₁ and PC₂ traces described different traces compared to the dough consistency curves. The loading spectra associated to PC₁ and PC₂ suggested that almost the same physicochemical and chemical mechanisms occur during the dough mixing at 51.8 or 54.4% water contents, but with kinetic and intensity differences. The 2D COS method allowed a sequence of chemical events occurring during mixing for the batters at 51.8 and 54.4% water contents to be tentatively proposed. The 2D COS did not give clear physicochemical differences between the three batters during mixing. The NIR results for the highly hydrated batter (56.7%) were difficult to analyse due to its high water content.     

Description of batter mixing using near infrared spectroscopy

The aim of the present study was to describe the physicochemical events occurring during batter mixing at different water contents (51.8, 54.4, and 56.7 g of water/100 g of dough) using near infrared (NIR) spectroscopy. An FT-NIR spectrometer over the 1000–2500 nm range with a fibre optic probe was used to record NIR spectra in-line. The analysis of both one-dimensional statistical method (principal components analysis) and two-dimensional statistical methods (generalised two-dimensional correlation spectroscopy) was conducted to evaluate the possibilities of NIR spectroscopy to monitor physical and physicochemical modifications observed during mixing of batter. The NIR results were in agreement with the physical and physicochemical analysis traditionally used to study bread dough mixing (consistency and glutenin depolymerisation). PCA on raw NIR spectra demonstrated that PC₁ describes the same traces as the dough consistency curves. PCA on raw NIR spectra can be used to monitor the batter mixing and to identify the NIR mixing time close to the t_peak.PCA on spectra after second derivative demonstrated that PC₁ and PC₂ traces described different traces compared to the dough consistency curves. The loading spectra associated to PC₁ and PC₂ suggested that almost the same physicochemical and chemical mechanisms occur during the dough mixing at 51.8 or 54.4% water contents, but with kinetic and intensity differences. The 2D COS method allowed a sequence of chemical events occurring during mixing for the batters at 51.8 and 54.4% water contents to be tentatively proposed. The 2D COS did not give clear physicochemical differences between the three batters during mixing. The NIR results for the highly hydrated batter (56.7%) were difficult to analyse due to its high water content.     

Substrate selectivity and inhibitor sensitivity affect xylanase functionality in wheat flour gluten–starch separation

Addition of xylanases (EC 3.2.1.8) that varied in their substrate selectivities and/or wheat xylanase inhibitor sensitivities in dough batter gluten–starch separation of wheat flour showed the importance of these enzyme characteristics for their functionality in this process. A xylanase from Aspergillus aculeatus (XAA) with selectivity for hydrolysis of water extractable arabinoxylan (WE-AX), which is not inhibited by wheat flour xylanase inhibitors decreased batter viscosity and improved gluten agglomeration behaviour. In contrast, a xylanase from Bacillus subtilis (XBS_i) with selectivity for hydrolysis of water unextractable arabinoxylan (WU-AX), which is in vitro inhibited by wheat flour xylanase inhibitors had a negative effect on gluten agglomeration at low enzyme dosages. As expected, solubilisation of WU-AX increased batter viscosities. At higher dosages however, this enzyme also improved gluten agglomeration because of degradation of both WE-AX and enzymically solubilised AX. A mutated B. subtilis xylanase (XBS_ni) with selectivity for hydrolysis of WU-AX comparable to XBS_i but which is not inhibited by wheat flour xylanase inhibitors, increased the level of large gluten aggregates as well as the total gluten protein recovery, even at lower dosages. Because of its inhibitor insensitivity, the solubilisation and degradation of AX proceeded further. An XBS_ni dosage approximately 4 times lower than XBS_i performed as well as its inhibited counterpart. The degradation of both WE-AX and WU-AX by XBS_ni improved the gluten agglomeration behaviour to a larger extent than the XAA treatment which primarily resulted in hydrolysis of WE-AX. The results confirm the detrimental impact not only of WE-AX, but also of WU-AX, on gluten agglomeration in a dough batter gluten–starch separation process. At the same time, they provide firm evidence that xylanases are not only inhibited by xylanase inhibitors in vitro, but are also partly inhibited in the industrial process in which they are used.     

Durum wheat breadmaking quality: Effects of gluten strength,protein composition,semolina particle size and fermentation time

The effects of particle size of granulars (semolina and flour combined), gluten strength, protein composition and fermentation time on the breadmaking performance were compared for eleven durum wheat genotypes of diverse strength from North America and Italy grown in the same environment. All genotypes were γ-gliadin 45 types (low-molecular weight glutenin subunit 2 patterns) associated with superior pasta-making quality. Three cultivars with high-molecular weight glutenin subunit 20 exhibited relatively weak gluten, confirming that this subunit is associated with weakness in durum wheat. Gluten strength as measured by a range of technological tests was directly and strongly related to the proportion of insoluble glutenin (IG) in granulars protein as determined by a spectrophotometric procedure. Reducing the particle size of granulars by gradual reduction shortened development time in both the farinograph and mixograph. Reducing granulars also increased starch damage and, accordingly, farinograph water absorption, but remix-to-peak baking absorption was unaffected due to increased fermentation loss for finer granulars. Neither loaf volume, nor remix-to-peak mixing time were affected by the particle size of the granulars indicating that regrinding is not an asset for baking provided there is adequate gassing power. Loaf volume was directly related to gluten strength and IG content, and inversely related to residue protein, a non-gluten containing fraction. When fermentation time was reduced from the standard 165 to 90 min and 15 min, all genotypes exhibited a progressive increase in loaf volume. Therefore, regardless of strength, short fermentation time is preferred when high volume durum wheat bread is desired. Some of the stronger durum genotypes exhibited remix-to-peak bread volume comparable to that expected of good quality bread wheat, indicating that there is potential to select for genotypes with improved baking quality in conventional breeding programs by screening for high content of insoluble glutenin.     

Thermal stability of wheat gluten protein: its effect on dough properties and noodle texture

There is a need to develop more sensitive and reliable tests to help breeders select wheat lines of appropriate quality. Gluten thermostability, measured by the viscoelasticity of heated gluten, was assessed for its usefulness in evaluating quality of wheats in breeding programs. Two sets of wheat samples were used: Set I consisting of 20 cultivars and/or breeders' lines (BL), with diverse dough strengths and allelic variations of high M_r glutenin subunits coded at the Glu-A1, Glu-B1 and Glu-D1 loci (N=20) and Set II consisting of 16 near isogenic BL of F7 generation that had been in a quality selection program for three years. Thermostability of the isolated wet gluten was determined by measuring its viscoelastic properties, and was related to noodle texture, flour protein content, protein composition, dough physical properties and other quality predicting tests.Viscoelasticity of heat-treated gluten, isolated with 2% NaCl solution, significantly correlated with most of the tests used to measure dough and/or gluten strength and Chinese white salted noodle texture. The rate of thermal denaturation of proteins depends on M_r and packing density. High ratios of monomeric proteins such as gliadins and low M_r glutenin subunits to high M_r glutenin subunits increase the thermostability of the gluten. The measurement of viscoelasticity of heat-denatured gluten can be a useful test to determine gluten quality. Our study showed that gluten viscoelasticity and most of the tests related to dough and/or gluten strength are independent of allelic variations of the high molecular weight glutenin subunits. This test has been developed for predicting white salted noodle quality.     

Factors Governing Levels and Composition of the Sodium Dodecyl Sulphate-Unextractable Glutenin Polymers During Straight Dough Breadmaking

The effect of several additives (1·215 μmol KIO₃, 0·892 μmol cysteine, endo-xylanase and 0·5% (w/w) rye-water-extractable arabinoxylans) on changes in the level and glutenin subunit composition of the sodium dodecyl sulphate (SDS)-unextractable protein during breadmaking was investigated. Protein extractability drastically increased during dough mixing and was enhanced both by cysteine and KIO₃. The mixing-induced increase in protein extractability was partly reversed during fermentation. Fermenting doughs containing endo-xylanase had a higher level of SDS-unextractable protein than control doughs, while with KIO₃the amount of SDS-unextractable protein remained very low. During baking most protein became SDS-unextractable. Bread baked from doughs with added KIO₃contained a significantly higher level of SDS-extractable protein. Changes in subunit composition of the SDS-unextractable glutenin polymers, determined with RP-HPLC, coincided with changes in protein extractability during dough processing. Mixing decreased the ratio of high to lowM_rglutenin subunits. Simultaneously, the relative proportions of the different highM_rglutenin subunits in the unextractable glutenin polymers changed. During fermentation changes in subunit composition of the SDS-unextractable glutenin were opposite to those during mixing.     

Large deformation stress relaxation and compression-recovery of gluten representing different wheat classes

Despite the great variety of physicochemical and rheological tests available for measuring wheat flour, dough and gluten quality, the US wheat marketing system still relies primarily on wheat kernel hardness and growing season to categorize cultivars. To better understand and differentiate wheat cultivars of the same class, the tensile strength, and stress relaxation behavior of gluten from 15 wheat cultivars was measured and compared to other available physicochemical parameters, including but not limited to protein content, glutenin macropolymer content (GMP) and bread loaf volume. In addition, a novel gluten compression–relaxation (Gluten CORE) instrument was used to measure the degree of elastic recovery of gluten for 15 common US wheat cultivars. Gluten strength ranged from 0.04 to 0.43 N at 500% extension, while the degree of recovery ranged from 5 to 78%. Measuring gluten strength clearly differentiated cultivars within a wheat class; nonetheless it was not a good predictor of baking quality on its own in terms of bread volume. Gluten strength was highly correlated with mixograph mixing times (r = 0.879) and degree of recovery (r = 0.855), suggesting that dough development time was influenced by gluten strength and that the CORE instrument was a suitable alternative to tensile testing, since it is less time intensive and less laborious to use.     

Using the Gluten Peak Tester as a tool to measure physical properties of gluten

The functional properties of wheat are largely dictated by composition and interactions of the gluten proteins. All flours contain gliadin and glutenin, but produce baked products of varying quality, which provides evidence that gluten proteins from different wheats possess different properties. A common method to study differences in gluten properties, which is utilized in this study, is fractionation/reconstitution experiments to understand how various gliadin to glutenin ratios and how fractions from different wheat sources affect gluten aggregation properties. Gliadin and glutenin from a vital wheat gluten were fractionated with 70% ethanol and reconstituted at various gliadin to glutenin ratios. Gliadin and glutenin from a Canadian eastern soft, eastern hard and western hard wheat (14% moisture) were fractionated and substituted between flours at the native gliadin to glutenin ratio. Gluten combinations were evaluated with a Gluten Peak Tester at constant temperature and mixing. Varying gliadin to glutenin ratio showed that 50:50 is optimal for fast gluten aggregation while amount of glutenin dictates strength. Substitution experiments showed that replacing good quality gluten fractions with those from a lower quality wheat decreases gluten quality, and vice versa. Data also showed that cultivar specific differences in gliadin and glutenin are more important in dictating gluten strength (torque), while gliadin to glutenin ratio dictates aggregation time (PMT) independent of the source of fractions. The study demonstrated the ability of the improved method to evaluate gluten aggregation by controlling for all variables except the one being tested. The data also revealed information about gluten aggregation properties never before seen.     

Using the Gluten Peak Tester as a tool to measure physical properties of gluten

The functional properties of wheat are largely dictated by composition and interactions of the gluten proteins. All flours contain gliadin and glutenin, but produce baked products of varying quality, which provides evidence that gluten proteins from different wheats possess different properties. A common method to study differences in gluten properties, which is utilized in this study, is fractionation/reconstitution experiments to understand how various gliadin to glutenin ratios and how fractions from different wheat sources affect gluten aggregation properties. Gliadin and glutenin from a vital wheat gluten were fractionated with 70% ethanol and reconstituted at various gliadin to glutenin ratios. Gliadin and glutenin from a Canadian eastern soft, eastern hard and western hard wheat (14% moisture) were fractionated and substituted between flours at the native gliadin to glutenin ratio. Gluten combinations were evaluated with a Gluten Peak Tester at constant temperature and mixing. Varying gliadin to glutenin ratio showed that 50:50 is optimal for fast gluten aggregation while amount of glutenin dictates strength. Substitution experiments showed that replacing good quality gluten fractions with those from a lower quality wheat decreases gluten quality, and vice versa. Data also showed that cultivar specific differences in gliadin and glutenin are more important in dictating gluten strength (torque), while gliadin to glutenin ratio dictates aggregation time (PMT) independent of the source of fractions. The study demonstrated the ability of the improved method to evaluate gluten aggregation by controlling for all variables except the one being tested. The data also revealed information about gluten aggregation properties never before seen.     

The dynamic rheological properties of glutens and gluten sub-fractions from wheats of good and poor bread making quality

The dynamic rheological properties of glutens and gluten fractions (gliadin and glutenin) of two U.K.-grown wheat cultivars, Hereward and Riband, having good and poor bread quality, respectively, were studied. Gluten and glutenin doughs from cv. Hereward had higher G' and lower tan δ values than those from cv. Riband at all frequencies studied. A more pronounced difference in G' and tan δ was observed between the glutenin doughs of the two wheats than between their respective gluten doughs. The rheological properties, i.e. G' and tan δ values, of gliadin doughs were similar for both wheats. Varying the gliadin/glutenin ratio by adding the isolated gliadin or glutenin sub-fractions to the parent glutens showed that the G' values decreased and the tan δ values increased as the gliadin/glutenin ratio was increased for both cultivars, indicating a considerable decrease in elasticity as the gliadin/glutenin ratio increased. The decrease in G' may be attributed to a plasticising effect of gliadin and ‘interference’ of gliadin with glutenin-glutenin interactions. The reduction in G' was much more pronounced when the gliadin/glutenin ratio was increased between 0.15 and 1.0 than between 1.0 and above. Gluten from cv. Hereward had higher G' and lower tan δ values than cv. Riband gluten at all gliadin/glutenin ratios, indicating that cv. Hereward gluten had greater elastic character than cv. Riband gluten. Although significant effects of other non-protein hydrocolloid components cannot be discounted, these observations are consistent with the view that the viscoelasticity of the glutenin sub-fraction of gluten and differences in the ratio of gliadin to glutenin are the main factors governing inter-cultivar differences in the viscoelasticity of wheat gluten.     

Study of the mechanism of improvement due to waxy wheat flour addition on the quality of frozen dough bread

Waxy wheat flour (WWF) was substituted for 10% regular wheat flour (RWF) in frozen doughs and the physicochemical properties of starch and protein isolated from the frozen doughs stored for different time intervals (0, 1, 2, 4 and 8 weeks) were determined to establish the underlying reasons leading to the effects observed in WWF addition on frozen dough quality. Using Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimeter (DSC) and X-ray Diffraction (XRD) among others, the gluten content, water molecular state, glutenin macropolymer content, damaged starch content, starch swelling power, gelatinization properties, starch crystallinity and bread specific volume were measured. Compared to RWF dough at the same frozen storage condition, 10% WWF addition decreased dry gluten and glutenin macropolymer contents and T₂₃ proton density of frozen dough, but increased the wet gluten content, T₂₁ and T₂₂ proton density. 10% WWF addition also decreased damaged starch content, but increased starch swelling power, gelatinization temperature and enthalpy, crystallinity of starch and bread specific volume of frozen dough. Results in the present study showed that the improvement observed due to WWF addition in frozen dough bread quality might be attributed to its inhibition of redistribution of water molecules bound to proteins, increase in damaged starch content and decrease in starch swelling power.     

小麦西昌69的EMS诱变系蛋白品质变异分析及种质筛选

为探讨甲基磺酸乙酯(ethyl methane sulfonate,EMS)诱变在小麦品质育种中的价值,了解EMS诱变小麦籽粒品质变异状况,筛选优良的变异材料,对1667份西昌69的EMS诱变系M 6代籽粒的蛋白质含量、淀粉含量、面筋含量、容重、面团形成时间和稳定时间等多个籽粒性状进行了测定,初步分析了诱变系的品质变化,并通过SDS-PAGE电泳法及高效液相色谱技术分析了其籽粒高分子量麦谷蛋白亚基(HMW-GS)的组分和不溶性蛋白聚合体的含量。共筛选到101份HMW-GS变异诱变系,分别为亚基缺失、亚基增生、亚基置换和亚基缺失且置换4种变异类型。其中,有28份诱变系的蛋白质含量、面筋含量、形成时间、稳定时间等多个籽粒品质性状及不溶性蛋白聚合体含量优于亲本,且千粒重相对稳定,可以作为优质种质资源用于小麦品质育种。     

Functional Properties of Wheat Glutenin

The importance of glutenin in bread-making quality has led to a substantial research effort. Studies on glutenin can be grouped into four categories: studies that determine the statistical relationships between the quantity of fractions and quality, studies of reconstitution and fortification, breeding and genetic modification, and those that assess structure–function relationships during processing. Statistical relationships between glutenin, glutenin fractions and glutenin polypeptides and quality have been established. The SDS or acetic acid unextractable glutenin correlated strongly with quality parameters. For highM_rglutenin subunits the relationships with quality are less strong. In some studies it was demonstrated that the presence of some highM_rglutenin subunits is correlated with the quantity of unextractable glutenin. Therefore, subunits are probably indirectly linked with bread-making qualityviathe quantity of unextractable glutenin. Recombination and fortification studies are hampered by changes in functionality of proteins after their separation. Recently, small scale tests have been developed in which small amounts of glutenin fractions can be studied. Controlled breeding studies have demonstrated the importance of highM_rglutenin subunits 5+10 and, to a lesser extent, 1 or 2* for quality. In most of these studies the quantity of unextractable glutenin is not reported. This hampers adequate conclusions on cause–effect relationships. During dough processing large changes occur in the extractability of glutenin. The significance of these changes for dough properties and bread quality still requires investigation.     

The mesoscopic structure in wheat flour dough development

The Farinograph time-to-peak is an important wheat flour quality parameter. It is well-established that insoluble glutenins correlate with the strength of the gluten network and dough mixing time. To learn more about the physical changes at the mesoscopic level, dough samples were prepared in the Farinograph for study with diffusion wave spectroscopy. It was confirmed that a space-filling network was formed by wheat gluten proteins (mainly glutenin). At peak development (9.0 min) it was shown that the starch granules were confined in the gluten network. After the time-to-peak, dough resistance weakened, showing an increase of the starch granule movement. Kneading disrupts insoluble glutenin particles, the disrupted glutenin becomes part of the Sodium Dodecyl Sulfate (SDS)-extractable proteins. Both soluble and insoluble wheat protein extracts have been characterized by light scattering techniques. The results derived from light scattering of the wheat protein fractions: particle radii, apparent molar mass and geometrical shapes, suggests that the disrupted glutenin aggregate shape and glutenin size heterogeneity could be more important for gluten network bulk consistency, connectivity and resistance at dough peak, than the apparent molar mass of the solubilized glutenins, reaching a maximum after dough peak.     

Effect of Water Unextractable Solids on Gluten Formation and Properties: Mechanistic Considerations

A miniaturised set-up for gluten-starch separation was used to systematically study the effect of water unextractable solids (WUS) on the formation and properties of gluten. The results showed that WUS not only have a negative effect on gluten yield, but also affect gluten and glutenin macropolymer (GMP) composition and rheological properties. The negative effect of WUS on gluten yield could be compensated for to a large extent, but not completely, by increasing mixing time and mixing water. Adding xylanase can effectively counteract the effect of WUS. On the basis of these results we hypothesize that WUS interfere with gluten formation in both a direct and an indirect way. WUS interfere indirectly by competing for water and thus changing conditions for gluten development. This effect can be corrected for by the combination of adding more 0·2% NaCl solution during dough mixing and a longer mixing time. The particulate nature of WUS requires that the direct effect occurs through an interaction between WUS particles and gluten particles. Both effects of WUS can be counteracted through the use of xylanase.     

A novel method to prepare gluten-free dough using a meso-structured whey protein particle system

This paper presents a novel concept for making an elastic dough using a structured protein suspension. The idea behind it is based on the hypothesis that a number of gluten properties originate from a particle structure present in the gluten network. Three different mesoscopically structured whey protein suspensions were produced: whey protein aggregates, a whey protein cold set gel and whey protein particles. Dough mixtures or batters were prepared by mixing the structured protein particle suspension with starch. Farinograph curves, small and large deformation experiments showed that the presence of a mesoscopic protein structure had a large impact on the properties of gluten-free starch mixtures. The whey protein that was structured into a mesoscopic particle suspension changed the starch mixture from a liquid into a cohesive material, having strain hardening properties.     

Relationships Between Chromosome 1B-encoded Glutenin Subunit Compositions and Bread-making Quality Characteristics of Some Durum Wheat (Triticum turgidum) Cultivars

The high and low M_r glutenin subunit compositions (controlled by the Glu-1 loci and the Glu-B3 locus, respectively) and the bread-making quality characteristics of 26 durum wheat (Triticum turgidum) genotypes were determined. The relationships between quality parameters and Glu-B1 and Glu-B3 controlled glutenin subunit composition were also investigated. The Glu-A1-controlled null allele was present in all the genotypes. High M_r subunits 20, 6 + 8 and 7 + 8 occurred in similar proportions in the cultivars analysed. The Glu-B3 low M_r allelic variants, LMW-1 and LMW-2, were both represented, with LMW-1 being present in lower proportion. Flour protein, SDS-sedimentation volume, dough strength (Alveograph W value), dough mixing time and bread loaf volume varied among the genotypes. Most samples had high Alveograph tenacity/extensibility (P/G) ratios, typical of tenacious gluten character. SDS-sedimentation volume, dough strength, dough mixing time and bread loaf volume were all interrelated. An association with flour protein content was observed only for mixing time, while the Alveograph tenacity/extensibility ratio was not correlated with the other parameters. Comparisons within the Glu-B1 and Glu-B3 loci indicated that the high M_r subunit 7 + 8 and the low M_r subunit LMW-2 had significantly greater beneficial effects on gluten strength and bread-making quality than the high M_r subunits 6 + 8 or 20 and the low M_r subunit LMW-1, respectively. High M_r subunit 6 + 8 had greater beneficial effects on quality than subunit 20.     

The Role of Gluten Proteins in the Baking of Arabic Bread

Fractionation and reconstitution/fortification techniques were utilised to study the role of gluten in Arabic bread. Glutens from two wheat cultivars of contrasting breadmaking quality were fractionated by dilute HCl into gliadin and glutenin. Gluten, gliadin and glutenin doughs from the good quality flour had higher G ′ and lower tan δ values than those from the poor quality flour at all the frequencies examined. Interchanging the gliadin and glutenin fractions between the reconstituted flours showed that the glutenin fraction is largely responsible for differences in the breadmaking performance. Fortification of an average quality flour with the gliadin and glutenin fractions from the poor and good quality flours, at the levels of 1% and 2% (protein to flour mass), induced marked differences in the mechanical properties of bread. The resilience of the loaves was not adversely affected by the addition of gliadins and increased, with a concomitant significant (p<0·05) improvement in quality, at the 2% level of fortification with gliadins from the good quality flour. Addition of glutenin resulted in loaves with leather-like properties that became particularly apparent at the higher level of fortification; the observed deterioration in quality paralleled the increase in the elastic character of the doughs. It is suggested that highly-elastic doughs are not compatible with the rapid expansion of gases at the high-temperature short-time conditions employed in the baking of Arabic bread and that there exists a threshold in dough elasticity beyond which a rapid decline in quality takes place.     

Breeding Wheat for Improved Milling and Baking Quality

Abstract

The molecular determinants of flour functionality and the targeted end-uses for flour define the methods used for improving wheat (Triticum aestivum L.) quality. We review major biochemical systems (gluten, grain hardness, starch, pentosans, lipids, and pigments) affecting wheat milling and baking quality. In early segregating generations (Fj to F₄), breeding programs select for the basic criteria that define a market class (e.g., grain hardness, color, kernel shape, and gluten strength). When desired and possible, improvement of highly heritable traits (e.g., PPO, GBSS mutations, and glutenin sub-units) in early generations is practiced through selection for desired seed or molecular phenotype. In advanced generations (F₅ to cultivar release), bake tests and rheological measures identify breeding lines fitting the subtle characteristics of a market class. Breeding programs favor rapid measures of end-use quality to rank breeding lines for relative end-use quality rather than time consuming protocols that would precisely measure the rheology of flour. Integration of genetic, biochemical, and rheological factors with breeding goals and realistic selection protocols results in the improvement of end-use quality for new cultivars of wheat.