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1.
The present study explored the effect of size reduction by superfine grinding on the performance and rheological properties of bran-enriched dough. Coarse (D50 = 328.98 μm) and superfine-ground (D50 = 50.76 and 28.37 μm) wheat brans were incorporated into the wheat dough to replace 10–30% of plain flour. Both fundamental and empirical tests were performed to assess the mixing properties, pasting properties, large deformation rheology, small deformation rheology, and stickiness of the dough. With the increasing amount of bran added, dough water absorption capacity increased, while the dough became less sticky and more rigid. Superfine grinding reduced the water retention capacity of the bran by 17–20%. Dough fortified with the finest bran (D50 = 28.37 μm) showed an overall better stability and uniaxial extensibility. However, the results suggested that superfine grinding not necessarily improve every aspect of dough performance, particularly the pasting properties. High peak and final viscosity were observed for dough fortified with superfine bran, indicating their end products, such as noodle, might exhibit high stickiness after cooking, and a high degree of starch retrogradation. Results of this study contributed to a better understanding of the modification effect of superfine grinding on dietary fibre.  相似文献   

2.
The concerns for a healthy diet in terms of the consumption of baked products as fibre-enriched ones have been highlighted by increased consumers demand, food legislation and targeting manufacturers offer to healthy food. The objective of this study was to assess the effect of some inulin-type products added in bread-making aimed at producing functional bakery goods. In this purpose some physico-chemical characteristics and technological properties of the Romanian wheat flour half-white with addition of 5%, 10%, 15% and 20% inulin commercial products (% basis flour) were evaluated. Rheological behaviour was investigated using mixolab Chopin and baking tests for fibre-enriched products were performed. Changes of the rheological behaviour were noticed, in terms of a general decreasing trend of dough machinability due to enzymatic reactions probably influenced by changing the ratio of the main compounds and their interactions. Overall the bread loaves characteristics mainly affected by inulin addition were the volume and crust colour.Results indicated that inulin potential as fibre enrichment in wheat bread is limited, 15% Fibruline DS being a maximum percent to be used in bread-making of half-white flour, a dosage above being critically for dough rheological behaviour and the quality of high-fibre bread.  相似文献   

3.
Traditional instruments used to evaluate dough and/or gluten rheological properties do not provide unambiguous separation of elastic and viscous behaviors. Recovery after shear creep and cyclic large deformation cyclic tensile testing were used here to decouple elastic and viscous effects. A large variation in the recoverable shear strain (∼7.2% to ∼28%) was seen for glutens from 15 U.S. popular common wheat cultivars with varying HMW subunits. Sedimentation values ranged from 29 to 57 ml for 12 hard wheat cultivars and 15 to 22 ml for three soft wheat cultivars. The tensile force at 500% extension ranged from 0.12 to 0.67 N for hard wheat glutens and from 0.10 to 0.20 for soft wheat glutens. However, the recoverable work after large extension was less than 40% of the total work of extension. In addition, recoverable work in tensile testing was highly correlated with the total work of extension (r2 = 0.97) and mixograph mix times (r2 = 0.81). Good to excellent bread volume was obtained for several cultivars from this sample set. This suggests that optimizing water absorption for mixing doughs to achieve maximal bread volume compensates for the wide range of viscoelastic behaviors of gluten.  相似文献   

4.
Selection for water absorption, a fundamental wheat quality parameter, has been a challenge in wheat breeding programs due to limited wheat materials available for milling and consequent time-consuming farinograph test. Hence, a high shear-based method, which requires 8 g of flour and less than 10 min per test, was proposed to predict flour water absorption using the Brabender GlutoPeak instrument. Highly significant positive linear relationship (r2 = 0.97) was found between GlutoPeak maximum torque and farinograph water absorption for 83 flour samples prepared with Bühler test mill from wheat lines under evaluation in the Canadian wheat variety registration trials. Similar strong correlation (r2 = 0.96) was obtained from flours (n = 63) prepared with Quadrumat Junior laboratory mill using small amount of wheat. Flour prepared either with Bühler test mill or Quadrumat Junior mill can be used for predicting water absorption effectively. GlutoPeak maximum torque was found to be independent of dough strength (r2 = 0.02) as measured by extensigraph. GlutoPeak test can be a powerful tool for rapid and reliable prediction of water absorption of wheat flour.  相似文献   

5.
The aim of this study was to examine the effect of dietary fibre addition to partially baked and frozen wheat rolls on the glycaemic index (GI).Healthy humans volunteers (n = 15) took part in the study. They were asked to attend six times in the early morning, over three weeks. Each tested four types of wheat rolls – two without dietary fibre addition: (1) fully baked, non-frozen (FBNF), (2) partially baked and frozen (PBF); and two with the addition of 10% dietary fibre: (3) fully baked, non-frozen (FBNF + F), (4) partially baked and frozen (PBF + F). Glucose solution was used as a reference food and tested twice. Blood glucose concentrations were measured before consumption, as well as at 15, 30, 45, 60, 90 and 120 min after the start of the meal. Dietary fibre consisted of oat fibre (75%) and of inulin (25%).It was concluded that both factors (freezing and fibre), applied to the wheat rolls at the same time, reduced statistically significantly (P ≤ 0.05) the glycaemic index by 34% – PBF + F (GI = 53 ± 7) compared to control – FBNF roll (GI = 87 ± 11). This effect was not observed when fibre supplementation or frozen storage were applied separately.  相似文献   

6.
为明确食用胶在面制食品中的作用,以3种商业小麦粉(特一粉、富强粉、上白粉)为试验材料,分别添加不同比例的海藻酸钠、黄原胶、卡拉胶,分析其对面团流变学特性的影响。结果表明,小麦粉添加0.15%~0.25%的海藻酸钠,面团稳定时间显著提高,弱化度显著降低;添加0.10%、0.20%和0.25%的海藻酸钠,面团最大拉伸阻力显著提高。添加0.02%、0.06%和0.10%的黄原胶,面团最大拉伸阻力显著提高;添加0.10%黄原胶的面团拉伸面积也显著提高。添加0.10%的卡拉胶,面团稳定时间、拉伸面积显著提高,弱化度显著降低。食用胶因小麦粉品质不同对面团流变学特性的影响也不同,除添加0.25%的海藻酸钠外,其他添加量的3种食用胶均可降低特一粉的面团吸水率,提高上白粉的吸水率。研究认为,海藻酸钠、黄原胶、卡拉胶可显著改善小麦粉的面团流变学特性,增强面团筋力。  相似文献   

7.
In this study, sixteen wheat varieties for cultivation in China were examined for the flour characteristics using the farinograph, extensograph and rheofermentometer, uniaxial extensional rheology employing the extensograph and the Kieffer extensibility rig and biaxial extension by uniaxial compression of mixed dough with and without yeast, rested and fermented dough, and steamed bread quality including specific volume and texture properties. Three statistical analysis methods including Pearson correlation, principle component and stepwise multiple regression analysis were carried out to correlate dough properties with steamed bread quality. Biaxial extension viscosity was positively correlated with texture properties (hardness and chewiness) of steamed bread (r = 0.521–0.685, p < 0.05). Based on the correlation coefficients and the model (r2 = 0.852, p = 0.003) obtained using stepwise multiple regression analysis, the best predictors for specific volume of steamed bread were the maximum resistance to extension of rested dough (r = 0.664, p < 0.01) and total work for breakage of fermented dough (r = 0.662, p < 0.01). Principal component analysis of rheological properties of fermented dough and flour characteristics provided more useful information for discriminating wheat flour quality and help breeders to select most convenient wheat flour for the steamed bread making.  相似文献   

8.
The effects of different percentages of barley flour (i.e. 0–25%) in wheat flours on the physico-chemical properties and structure of dough and bread were investigated. As the percentage of barley flour in mixed flour was increased, its protein and gluten contents decreased whereas the ash content and enzyme activity increased. The rheological characteristics of the four dough mixes were studied using Farinograph, Extensograph and Alveograph. The water absorption (p < 0.01) and stability (p < 0.05) decreased significantly as the percentage of barley flour increased, while no changes were observed in the extensibility and maximum heights. Significant differences were observed in the structural and physical properties as well as in the image analysis of breads. With the increase in the percentage of barley flour, the crumb apparent density decreased (p < 0.1) whereas the porosity (i.e., fraction to total volume) increased (p < 0.1). Overall, the shape and pore structure at 10% barley flour (W90B10) were similar to the pure wheat flour bread, while addition at 15 and 25% of barley flour (W85B15 and W75B25) showed more non-uniform and larger pores.  相似文献   

9.
The objective of this study was to evaluate the effects of the incorporation of oat β-glucan (OβG) on the hydration, rheological and fermentation properties of wheat flour dough. Wheat flour was substituted with OβG at levels varying from 1 g/100 g–5 g/100 g. The addition of OβG significantly increased water absorption and dough development time. The dilution effect of OβG, competing for water and interaction between OβG and gluten proteins, deteriorated the gluten network structure and reduced the stability of dough. Rheological evaluation revealed an increasing tendency to solid-like behavior with increasing addition of OβG. Regarding dough fermentation properties, OβG had no effect on yeast activity but reduced the gas retention capacity of dough. Our findings indicate that OβG is a key component that determines the properties of dough, and excess OβG exhibited poorer processing characteristics compared with control.  相似文献   

10.
Wheat filter flours are by-products obtained from air-classification of wheat flour. Physicochemical and rheological properties of wheat filter flours were investigated in the present study. Average values of crude protein, gluten, lipid and damaged starch content of filter flours were higher than those of standard flours for the same batch. The positive correlation of particles with size <20 μm and damaged starch was found. Moreover, the filter flours had higher water absorption, stability time except head milling filter flour samples. Short peak time and low peak viscosity were also observed. Different composition of wheat filter flours may be an important factor influencing its properties. This study is very useful for exploring the utilization of wheat filter flours in the food industry.  相似文献   

11.
Effect of adding flaxseed flour (10%, 20% and 30% w/w) to wheat flour on rheological properties of dough, including water absorption, stability and development time, extensibility and resistance to extension, was studied at 45, 90 and 135 min proving time. Qualitative properties of toast regarding staling (after 24 and 72 h) were determined. Phenolic compounds, peroxide values, sensory characteristics and color indices of the breads were evaluated. The results indicated that water absorption and development time increased as the proportion of flaxseed increased in dough. Stability decreased with the increment of flax flour compared to control sample (100% wheat flour). Extensibility and resistance to extension of flaxseed samples respectively decreased and increased comparing to those of control sample. Staling in toast with 20% flaxseed flour was seen to be lower than that of the control. Adding flax flour caused phenolic compounds to increase, however it decreased peroxide value. Bread color parameters L and a reduced by adding flax flour, while parameter b did not show significant different compared to the control (p < 0.05). Results of sensory evaluation indicated that brightness of the toasts decreased with increasing flaxseed flour and that 30% flaxseed toast had the lowest score for overall acceptability.  相似文献   

12.
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.  相似文献   

13.
The measurement of baking quality by dough mixing and viscoelastic tests is often labor-intensive and time-consuming, thus the possibility to predict these rheological parameters either by rapid tests or genomic selection models based on molecular markers was investigated in this study. A winter wheat breeding population of 128 genotypes was measured for its rheological parameters, gluten peak indices and other rapid test variables in multiple environments. The prediction accuracy of the rheological parameters was assessed in different cross-validation schemes, reflecting scenarios encountered either in food-processing or by plant breeders. Predictions based on gluten peak indices (r = 0.41–0.82) outperformed the other investigated rapid tests in the food-processing scenario. The combination of gluten peak indices with sedimentation value and protein content gave furthermore the overall highest prediction accuracy (r = 0.70). Cross-validation results from the plant breeding scenario revealed that the prediction accuracy of genomic selection models was merely slightly lower (r = 0.42) than using a combination of sedimentation value and protein content (r = 0.44). Merging gluten peak indices with genomic estimated breeding values resulted in a higher accuracy than either method alone (r = 0.52), and was a promising strategy to select for baking quality in wheat breeding.  相似文献   

14.
One hundred and ninety-two wheat genotypes including 150 released varieties and 42 germplasm lines were evaluated for solvent retention capacity (SRC) tests using 1 g of flour and 1 g of wholemeal to determine relationships with mixing properties of their doughs. Strong positive correlations (p<0.001) were observed between different SRCs (using both wholemeal as well as flour) and Farinograph water absorption (FWA). In multiple regression analysis, flour water SRC explained 41.2%, sodium carbonate SRC 24.6%, sucrose SRC 20.7% and protein content 13.5% of the total variability (multiple r=0.91) in FWA. The data demonstrated that water absorption is governed mainly to starch damage and pentosan content of the flour. Based on multiple regression analysis an equation was developed to predict FWA and a very high positive correlation (r=0.91) was observed between predicted FWA and actual FWA. LASRC exhibited significant positive correlations (p<0.001) with Farinograph and Mixograph parameters related to gluten strength such as the Farinograph peak time and mixing tolerance index and the mixograph peak time and peak dough resistance. Wholemeal flour SRCs accounted for 48% of the variation in FWA and was highly significant (p<0.001). The average values of FWA of corresponding clusters made using wholemeal and flour SRCs were not significantly different. This demonstrates that wholemeal SRCs together with grain protein content can be used to screen early generation lines for FWA. Since large numbers of diverse genotypes were used in the estimation of various parameters, high correlations observed between SRCs and functional properties including water absorption have obvious implications in breeding programs for the improvement of wheat cultivars.  相似文献   

15.
Reduced glutathione (GSH) commonly exists in wheat flour and has remarkable influence on gluten properties. In this study, effect of GSH on the gelatinization and retrogradation of wheat flour and wheat starch were investigated to better understand the GSH-gluten-starch interactions in wheat flour. Compared with wheat starch, wheat flour showed significant decreases in peak and final viscosity, and gelatinization onset temperature with increasing GSH concentration. GSH depolymerized gluten and thereby broke down the protein barrier around starch granules to make the starch easily gelatinized. However, the interaction between GSH and wheat starch restrained starch swelling. GSH addition resulted in weakened structure with higher water mobility in freshly gelatinized wheat flour dispersions but decreased water mobility in wheat starch dispersions. After storage at 4 °C for 7 d, GSH increased elasticity and retrogradation degree in wheat flour dispersions but retarded retrogradation in wheat starch dispersions. The results indicated that GSH promoted retrogradation of wheat flour, which mainly attributed to the depolymerized gluten embedding in the leached starch chains, and inhibiting the re-association of amylose, and subsequently promoted the starch intermolecular associations and starch retrogradation. This study could provide valuable information for the control of the quality of wheat flour-based products.  相似文献   

16.
Addition of a gluten-free flour such as sorghum has negative impact on the quality of wheat dough for bread making. One of the methods which can be used to promote the quality of sorghum-wheat composite dough is to extrude the sorghum flour before incorporation. In this regard, to produce a dough with appropriate bakery properties sorghum flour was extruded at 110 °C and 160 °C die temperature with 10%, 14% and 18% feed moisture. The effect of extruded sorghum flour incorporation (10%) on rheological (farinography and stress relaxation behavior), morphological and temperature profile of sorghum-wheat composite dough were evaluated. Extrusion cooking altered the sorghum-wheat composite dough properties through partial gelatinization of starch granules. Addition of extruded sorghum flour increased the water absorption and dough development time but it decreased the dough stability. Native sorghum-wheat composite dough showed viscoelastic liquid-like behavior whereas addition of sorghum flour extrudate changed dough to a more viscoelastic solid-like structure. Maxwell model was more appropriate than Peleg model to describe the viscoelasticity of the sorghum-wheat composite dough. Extrusion cooking decreased composite dough elasticity and viscosity. Sorghum extrudate increased the heating rate of composite dough crumb during baking. Addition of extruded sorghum flour formed a non-uniform and less compact dough structure. As a result, dough containing extruded sorghum flour had a good potential for producing a high-yielding bread in a short time of baking.  相似文献   

17.
Traditional instruments used to evaluate dough and/or gluten rheological properties do not provide unambiguous separation of elastic and viscous behaviors. Recovery after shear creep and cyclic large deformation cyclic tensile testing were used here to decouple elastic and viscous effects. A large variation in the recoverable shear strain (∼7.2% to ∼28%) was seen for glutens from 15 U.S. popular common wheat cultivars with varying HMW subunits. Sedimentation values ranged from 29 to 57 ml for 12 hard wheat cultivars and 15 to 22 ml for three soft wheat cultivars. The tensile force at 500% extension ranged from 0.12 to 0.67 N for hard wheat glutens and from 0.10 to 0.20 for soft wheat glutens. However, the recoverable work after large extension was less than 40% of the total work of extension. In addition, recoverable work in tensile testing was highly correlated with the total work of extension (r2 = 0.97) and mixograph mix times (r2 = 0.81). Good to excellent bread volume was obtained for several cultivars from this sample set. This suggests that optimizing water absorption for mixing doughs to achieve maximal bread volume compensates for the wide range of viscoelastic behaviors of gluten.  相似文献   

18.
The rheological characteristics of gluten-free doughs and their effect on the quality of biologically leavened bread were studied in amaranth, chickpea, corn, millet, quinoa and rice flour. The rheological characteristics (resistance to extension R, extensibility E, R/E modulus, extension area, stress at the moment of dough rupture) were obtained by uniaxial dough deformation. Specific loaf volume of laboratory prepared gluten-free breads was in significant positive correlation with dough resistance (r = 0.86), dough extensibility (r = 0.98) and peak stress at the moment of dough rupture (r = 0.96). Even if the correlation between R/E modulus and the characteristics of loaf quality were not significant, the breads with the highest specific loaf volume were prepared from flours with R/E closer to the wheat check sample (18 N?mm-1). The results showed, in general, good baking flours exhibited stronger resistance to extension and greater extensibility, but differences found were not directly related to the results of baking tests.  相似文献   

19.
The effect on baked muffins of progressively replacing wheat flour with resistant starch (RS) was studied. Muffin volume and height and the number and area of gas cells decreased significantly when the RS level reached about 15% (by weight of total formulation) or higher. Rheological properties of the raw batters were studied: the mechanical spectra of batters at 25 °C, the evolution of the dynamic moduli (G′ and G″) with rising temperatures (from 25 to 85 °C) and the mechanical spectra at 85 °C were obtained from oscillatory rheological tests. The decrease in the viscosity and in the elastic properties of the muffin batter as the flour was increasingly replaced by RS was related to the baking performance of the final baked products.  相似文献   

20.
Whole wheat is well known by consumers as a health-providing ingredient. Nevertheless, in extruded products it leads to textures that are less favorable to consumer preference compared to its refined flour. An understanding of the effect of extrusion on whole wheat properties is therefore necessary to improve its texture. Whole wheat flour was extruded under varying conditions of water content (18 or 22%), screw speed (400 or 800 rpm) and barrel temperature (140 or 180 °C) and its physicochemical properties were measured. Changing the extrusion conditions significantly modified the volumetric expansion index (between 9.1 and 20.6) and longitudinal expansion (between 0.93 and 2.98) of the samples. Interestingly, changing the extrusion conditions did not significantly modify the sectional expansion. Increasing barrel temperature, water content or screw speed decreased the shear viscosity of the melt. This can be explained by plasticizing effects and modification of starch properties. The change in shear viscosity at the die can mostly explain the effect of process conditions on volumetric expansion of the extruded whole wheat. The stress at rupture of the extruded samples was varied between 0.49 and 1.86 MPa depending on process conditions. It was the lowest at high water content and low screw speed.  相似文献   

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