Effects of Transglutaminase Enzyme on Fundamental Rheological Properties of Sound and Bug‐Damaged Wheat Flour Doughs

Transglutaminase (TG) catalyzes the formation of nondisulfide covalent crosslinks between peptide‐bound glutaminyl residues and ∊‐amino groups of lysine residues in proteins. Crosslinks among wheat gluten proteins by TG are of particular interest because of their high glutamine content. Depolymerization of wheat gluten proteins by proteolytic enzymes associated with bug damage causes rapid deterioration of dough properties and bread quality. The aim of the present study was to investigate the possibility of using TG to regain gluten strength adversely affected by wheat bug proteases. A heavily bug‐damaged (Eurygaster spp.) wheat flour was blended with sound cv. Augusta or cv. Sharpshooter flours. Dynamic rheological measurements, involving a frequency sweep at a fixed shear stress, were performed after 0, 30, and 60 min of incubation on doughs made from sound or blended flour samples. The complex moduli (G* values) of Augusta and Sharpshooter doughs blended with 10% bug‐damaged flour decreased significantly after 30 min of incubation. These dough samples were extremely soft and sticky and impossible to handle for testing purposes after 60 min of incubation. To test the possibility of using TG to counteract the hydrolyzing effect of bug proteases on gluten proteins, TG was added to the flour blends. The G* values of TG‐treated sound Augusta or Sharpshooter doughs increased significantly after 60 min of incubation. The G* values of the Augusta or Sharpshooter doughs blended with bug‐damaged flour increased significantly rather than decreased after 30 and 60 min of incubation when TG was included in the dough formulation. This indicates that the TG enzyme substantially rebuilds structure of dough hydrolyzed by wheat bug protease enzymes.     

Protein and Quality Characterization of Triticale Translocation Lines in Breadmaking

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 (R_max) 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, R_max, 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.     

Effect of Adding Exogenous Oxidative Enzymes on the Activity of Three Endogenous Oxidoreductases During Mixing of Wheat Flour Dough

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.     

End-Use Quality of Flour from Rhyzopertha dominica Infested Wheat

The objective of this study was to evaluate how Rhyzopertha dominica infestation of stored wheat grain affects the rheological and baking properties of bread made with the milled flour. Wheat samples were infested with R. dominica and stored for up to 180 days at room temperature. Every 45 days, samples of wheat were collected and evaluated for insect population and flour yield. Flour milled from these wheat samples was evaluated for color reflectance, pH, fat acidity, and rheological properties which were measured by a farinograph. Loaves of bread were baked using a straight-dough procedure. Volume, height, and weight of the loaves were evaluated. None of the analyses performed on the control wheat flours showed any changes during the storage period, and they were similar to the initial wheat. The insect population increased during storage of the wheat up to 90 days, and the flour yield decreased with the storage up to 180 days. Flours from insect-infested wheat absorbed more water than did flours from control wheat. Dough stability and dough development times of infested flours decreased. Bread volume showed a progressive decline throughout the storage experiment. In conclusion, flour from insect-infested wheat exhibited changes in rheological properties such as dough stability, dough development times, water absorption, and mixing stability; bread had an offensive odor; and volume and loaf characteristics were negatively affected.     

Effects of Laccase and Ferulic Acid on Wheat Flour Doughs

The effects of a laccase from the fungus Pycnoporus cinnabarinus on the mixing of a wheat flour dough with or without added ferulic acid (FA) were studied. Laccase reduced dough time‐to‐peak and accelerated dough breakdown in comparison with the control. Its effect was enhanced with FA. The water extractability of arabinoxylans (AX) increased during mixing of a dough free of added laccase, especially with exogenous FA. At the same time, the extractability of FA decreased during mixing. Added FA may have competed with endogenous AX feruloyl esters, inhibiting partly oxidative gelation. Laccase decreased AX extractability by chain cross‐linking through oxidative dimerization of feruloyl esters. FA and, moreover, FA plus laccase, increased the oxidation of sulfhydryl (SH) groups. FA and, even more, FA in combination with laccase, increased the rate of protein depolymerization during mixing. FA and the products of FA laccase oxidation participated in a redox reaction involving SH groups. A coupling reaction involving enzymatically generated feruloyl radicals and thiol radicals generated through the mechanical breakdown of inter‐chain disulfide bonds might explain these results.     

Formation of Homopolymers and Heteropolymers Between Wheat Flour and Several Protein Sources by Transglutaminase‐Catalyzed Cross‐Linking

The effect of different protein sources (soy flour, lupin flour, egg albumin, gelatin powder, protein‐rich beer yeast flour) on wheat dough functionality was tested by determining gluten index, texture properties, and thermomechanical parameters. Transglutaminase (TG) was also added to improve the dough functionality by forming cross‐links. The presence of protein sources had a significant effect on the gluten index, with the exception of lupin flour. Gelatin and the presence of TG resulted in significant single effects on the texture properties of the wheat‐protein dough. All the protein sources significantly modified the mixing characteristics of the dough or the thermal behavior. Capillary electrophoresis studies of the water‐soluble, salt‐soluble, and glutenin proteins indicated that interactions were mainly within proteins, thus homologous polymers. Scanning electron microscopy studies of the doughs made from blends of wheat and protein sources doughs supported the formation of heterologous structures in the wheat‐lupin blends. The combination of TG and lupin would be a promising method to be used on the treatment of insect‐damaged or weak flours, to increase the gluten strength.     

Effects of Oat Grain Hydrothermal Treatments on Wheat-Oat Flour Dough Properties and Breadbaking Quality

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

Fermented Sorghum as a Functional Ingredient in Composite Breads

Whole sorghum flour was fermented (a five‐day natural lactic acid fermentation) and dried under forced draught at 60°C, and evaluated for its effect on sorghum and wheat composite bread quality. In comparison with unfermented sorghum flour, fermentation decreased the flour pH from 6.2 to 3.4, decreased total starch and water‐soluble proteins, and increased enzyme‐susceptible starch, total protein, and the in vitro protein digestibility (IVPD). Fermentation and drying did not decrease the pasting temperature of sorghum flour, but slightly increased its peak and final viscosity. In comparison with composite bread dough containing unfermented sorghum flour, fermented and dried sorghum flour decreased the pH of the dough from 5.8 to 4.9, increased bread volume by ≈4%, improved crumb structure, and slightly decreased crumb firmness. IVPD of the composite bread was also improved. Mixing wet fermented sorghum flour directly with wheat flour (sourdough‐type process) further increased loaf volume and weight and reduced crumb firmness, and simplified the breadmaking process. It appears that the low pH of fermented sorghum flour inactivated amylases and increased the viscosity of sorghum flour, thus improving the gas‐holding capacity of sorghum and wheat composite dough. Fermentation of sorghum flour, particularly in a sourdough breadmaking process, appears to have considerable potential for increasing sorghum utilization in bread.     

Application of Pregerminated Brown Rice for Breadmaking

Pregerminated brown rice (PGBR) prepared by immersing in water was used for breadmaking, and effects on the dough properties and bread qualities were studied to compare with the ungerminated brown rice (BR). The substitution of BR or PGBR for wheat flour produced smaller specific volume in bread than in the control bread without BR or PGBR along with the increasing amount of substitution. However, the bread samples containing BR or PGBR suppressed staling during storage. The improving effect was especially obvious for substitutions of 10 and 20% PGBR as compared with BR. PGBR made viscous dough and retarded the staleness of bread compared with BR. γ‐Aminobutyric acid and oryzanol did not contain in the final BR and PGBR substituted bread, and phytic acid was decomposed ≈54 and 45% for 30% BR and 30% PGBR substituted breads, respectively. But ferulic acid was quite stable in the final baked product. As a result, substitution of PGBR for wheat flour improved the bread quality.     

Effects of Commercial Hydrolytic Enzyme Additives on Japanese‐Style Sponge and Dough Bread Properties and Processing Characteristics

The effects of increasing levels of eight commercial fungal enzymes enriched in four types of activity (α‐amylase, protease, xylanase, or cellulase) on Japanese‐style sponge and dough bread quality and processing characteristics have been studied using a Canadian red spring wheat straight‐grade flour. At optimum levels, the enriched α‐amylases, xylanases, and cellulases increased loaf volume and bread score and reduced crumb firmness, while the proteases only reduced crumb firmness. For α‐amylases, xylanases, and cellulases, optimum levels for crumb firmness were obtained at higher levels of addition than for loaf volume and bread score. At high levels of addition, all four enriched enzyme types reduced loaf volume and bread score and increased crumb firmness relative to optimum levels, with the proteases showing the most dramatic effects. α‐Amylases and cellulases had little impact on dough mixing requirements, while xylanases increased and proteases greatly reduced mixing requirements. All enzymes at optimum levels reduced sheeting work requirements, resulting in softer more pliable dough. Optimum bread properties for α‐amylases, xylanases, and cellulases were attained within a relatively narrow range of dough sheeting work values. This similarity in response suggests a dominant common nonspecific mechanism for their improver action, which is most likely related to water release and the resulting impact on physical dough properties.     

Breadmaking Quality of Selected Durum Wheat Genotypes and Its Relationship with High Molecular Weight Glutenin Subunits Allelic Variation and Gluten Protein Polymeric Composition

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.     

Restoration of Breadmaking Properties to Frozen Dough by Addition of Sugar and Yeast and Subsequent Processing

We prepared bread dough A (a mixture of wheat flour, sugar, salt, and water), bread dough B (a mixture of bread dough A and yeast), and bread dough C (first‐proofed, molded, and second‐proofed bread dough B) and froze them at –20°C for six days. They were thawed at 4°C for 16 hr and subjected to their breadmaking processes. The results indicated that breadmaking properties (bread height [mm] and specific volume [cm³/g]) after bread dough A and B processes were the same as those of control bread dough (unfrozen dough). However, in the case of bread dough C, the resulting bread showed depression of the properties. The amount of centrifuged liquid from thawed bread dough C increased. Sugar was added to thawed bread dough C (bread dough C‐1), and then yeast was further added to bread dough C‐1 (bread dough C‐2), and they were subjected to the breadmaking process. The results showed that the breadmaking properties of bread dough C‐2 were the same as those of the control. It was further found that when the first proof step in the bread dough C‐2 process was omitted, the breadmaking properties were depressed. Frozen and thawed bread dough C was packed into a plastic tube, and extension of the dough was compared with that of control dough under reduced pressure. Bread dough C extended to 50 mm, compared with 70 mm for control dough. First proof, mold, and second proof steps of dough C‐2 caused it to extend to the same height as control dough. It was concluded that the increased amount of the separated liquid in thawed dough C caused depression of breadmaking properties resulting from lack of water in the appropriate places to provide the expected properties, but these properties could be restored to the levels of control bread dough by the addition of sugar and yeast following the first proof, mold, and second proof steps.     

Evaluation of Various Baking Methods for Polished Wheat Flours

Flour qualities of polished wheat flours of three fractions, C‐1 (100–90%), C‐5 (60–50%), and C‐8 (30–0%), obtained from hard‐type wheat grain were used for the evaluation of four kinds of baking methods: optimized straight (OSM), long fermentation (LFM), sponge‐dough (SDM) and no‐time (NTM) methods. The dough stability of C‐5 in farinograph mixing was excellent and the maturity of polished flour doughs during storage in extensigraph was more improved than those of the commercial wheat flour (CW). There were no significant differences in the viscoelastic properties of CW dough after mixing, regardless of the baking method, while those of polished flour doughs were changed by the baking method; this tendency became clear after fermentation. The polished flours could make a better gluten structure in the dough samples after mixing or fermentation using LFM and SDM, as compared with other baking methods. Baking qualities such as specific volume and storage properties of breads from all polished flours made with SDM increased more than with other methods. In addition, viscoelastic properties of C‐5 and C‐8 doughs fermented by SDM were similar to those of CW, and the C‐5 breadcrumb showed softness similar to that of the CW. Also, SDM could make C‐5 bread with significantly higher elasticity and cohesiveness after storage for five days when compared with CW bread. Therefore, SDM with long fermentation, as compared with other baking methods, was considered suitable for use with polished flours to give better effects on dough properties during fermentation, resulting in more favorable bread qualities.     

Protein and Quality Characterization of Complete and Partial Near‐Isogenic Lines of Waxy Wheat

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 (R_max) (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.     

Comparison of Unifactorial and Mixture Approaches for Optimization of Mixing Time and Flour and Water Contents in Breadmaking Formulas

A unifactorial approach was compared with a multifactorial approach, based on mixture theory, using bread optimization. The effects of dough weight and formula, as well as mixing time, on bread properties were investigated. The unifactorial approach indicated that increasing the weight of water added to flour increased bread weight. Changing the weight of water in dough also changed the proportion of all the ingredients and total dough weight. The unifactorial approach could not unequivocally indicate the variable responsible for increases in bread weight. Conversely, the multifactorial approach clearly indicated that increased dough weight increased bread weight.     

Effect of RS4 Resistant Starch on Dietary Fiber Content of White Pan Bread

Bread flour was replaced with 5, 10, 15, 20, or 25% phosphorylated cross‐linked RS4 resistant wheat starch and augmented with vital wheat gluten to maintain original flour protein content. Effect on dough and bread characteristics, total dietary fiber content, and consumer acceptability were evaluated. Mixograph water absorption was not affected by addition of 5, 10, and 15% RS4; however, a significant 2% increase in absorption occurred with 20 and 25% RS4 addition. Mixograph mix time was increased by 15 s with the addition of 5, 10, and 15% RS4, by 30 s with 20% added RS4, and by 45 s with 25% added RS4. There was not a difference in farinograph absorption of doughs containing all levels of added RS4. Farinograph mixing time increased as addition level increased up to 15% and then decreased at higher addition levels. In general, dough strength and extensibility were not affected by RS4 addition. Levels of added RS4 up to 20% did not affect bread volume. Loaves with 15, 20, and 25% added RS4 contained sufficient fiber to meet the “good source of fiber” claim. A consumer sensory panel reported no difference in liking of flavor, texture, or overall liking of bread containing 15, 20, and 25% RS4.     

Effect of Gaseous Acetic Acid on Dough Rheological and Breadmaking Properties

Breads baked from wheat flours (protein contents 14.1–16.5% at 14.0% mb) that were pretreated with 2–3 mL of gaseous acetic acid per kg of wheat flour, showed maximum bread height and specific volume (cm³/g). Flour-water suspension and the crumb pH values were gradually decreased with increased amounts of acetic acid. Gas generation and dough expansion tests with bread dough showed that the addition of the same amount of acetic acid, which achieved maximum specific volume, also showed the highest rate of gas generation and dough expansion. However, increasing acetic acid decreased these values. Scanning electron microscope (Cryo-SEM) observation showed that the bread dough made from the same acetic acid-treated flour indicated continuum and no cracks in the dough matrix. Evaluation of mixograms showed the decrease of mixing stability with increased acetic acid levels. Viscosity and water binding capacity of flour-water suspensions were sharply increased by the addition of acetic acid at pH 5.0–3.5.     

Effect of Wheat Bran on Dough Rheology and Final Quality of Chinese Steamed Bread

Wheat bran is a low‐cost by‐product abundantly produced by the wheat flour industry. As a staple food of China, Chinese steamed bread (CSB) represents about 40% of China's wheat consumption. This study investigated the effects of incorporating wheat bran into the CSB at different levels (5, 10, and 15%). The dough behavior was measured by analyzing rheological properties. Quality of CSB was analyzed from two perspectives: physical properties and nutritional quality. For physical properties, specific volume, loaf height, moisture, and texture were measured by 1 . The predicted glycemic response of the bread was analyzed by using an in vitro digestion method. The results illustrated that the incorporation of wheat bran into wheat flour reduced the extensibility of the dough, decreased specific volume, and increased bread hardness, gumminess, and chewiness. However, this study also showed that addition of wheat bran can decrease the predicted glycemic response of steamed bread by up to 39%.     

Dough Properties and Bread Quality of Wheat–Barley Composite Flour as Affected by β‐Glucanase

Barley is rich in nutritionally positive compounds, but the quality of bread made of wheat–barley composite flours is impaired when a high percentage of barley is used in the mixture. A number of enzymes have been reported to be useful additives in breadmaking. However, the effect of β‐glucanase on breadmaking has scarcely been investigated. In this paper, the influence of different levels (0.02, 0.04, 0.06, and 0.08%, based on composite flour) of β‐glucanase (100,000 U/g) on the properties of dough and bread from 70% wheat, 30% barley composite flour were studied. Although dough development time, dough stability, and protein weakening value decreased after β‐glucanase addition, dough properties such as softness and elasticity as well as bread microstructure were improved compared with the control dough. β‐Glucanase also significantly improved the volume, texture, and shelf life of wheat–barley composite breads. The use of an optimal enzyme concentration (0.04%) increased specific volume (57.5%) and springiness (21%), and it reduced crumb firmness (74%) and staling rate. Bread with added β‐glucanase had a better taste, softness, and overall acceptability of sensory characteristics compared with the control bread. Moreover, the quality of wheat–barley composite bread after addition of 0.04% β‐glucanase was nearly equal to the quality of pure wheat bread. These results indicate that dough rheological characteristics and bread quality of wheat–barley composite flour can be improved by adding a distinct level of β‐glucanase.     

麦麸酚基木聚糖对发酵面团特性和馒头品质的影响

为了提高麦麸的附加值、馒头的品质以及增强馒头的营养价值,该试验以小麦粉为原料,采用2个分子量的麦麸酚基木聚糖（820、581 kD）,研究不同添加量（0.25%、0.5%、1.0%、2.0%）对发酵面团特性以及馒头品质的影响。结果表明：随着麦麸酚基木聚糖添加量的增加,发酵面团的弹性模量、质子密度A22先增加后下降,黏性模量、质子密度A23增加,弛豫时间T22下降;馒头的亮度下降,红度和黄度增加,比容、黏聚性、回复性先增加后下降,硬度、咀嚼性先下降后上升,黏附性下降,馒头的感官得分先上升后下降。高分子量的麦麸酚基木聚糖,其发酵面团的弹性模量和黏性模量变幅较大,弛豫时间T22、T23较大、质子密度A21较小,低分子量的麦麸酚基木聚糖,其馒头比容和弹性较大,但馒头硬度和咀嚼性相对也较大。麦麸酚基木聚糖添加量在0.5%时,对发酵面团以及馒头品质改善效果最好。添加量在1.0%内,发酵面团特性以及馒头品质均可接受。高分子量的酚基木聚糖对发酵面团以及馒头品质改善效果高于低分子量的酚基木聚糖。研究结果为麦麸酚基木聚糖广泛应用于馒头中,提高馒头品质及营养价值提供理论依据。