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Effect of tef [Eragrostis tef (Zucc.) Trotter] grain flour addition on viscoelastic properties and stickiness of wheat dough matrices and bread loaf volume
Abstract
Currently, consumers’ preference toward baked goods with additional (functional and nutritional) value is increasing, leading food industries to look at natural nutrient-dense alternatives like tef grain. Impact of tef grain flour incorporation (three Ethiopian varieties: DZ-01-99, DZ-Cr-37 and DZ-Cr-387 at 10, 20, 30 and 40 % levels) on dough viscoelastic profiles and stickiness of wheat-based dough matrices were investigated. Oscillatory and creep-recovery tests together with dough stickiness were performed. Incorporation of tef flours affected the structure of the dough matrices visibly by reducing viscoelastic moduli, and the maximum stress doughs can tolerate before its structure is broken and increased dough instantaneous and retarded elastic compliances. Effect of dose was not always significant in the parameters measured. Tef grain flour incorporation up to 30 % level led to breads with higher loaf volume than the control associated with optimal consistency and higher deformability of doughs. Higher tef doses increased dough stickiness. This will affect dough handling and shaping/flattening to get continuous strands or thin sheets. On average, the DZ-Cr-37-supplemented doughs exhibited higher elastic and viscous moduli, lower compliances and higher steady-state viscosity and led to significantly lower loaf bread volumes. Hence, based on dough viscoelastic and stickiness properties, incorporation of DZ-01-99 and DZ-Cr-387 into wheat flour-based formulations could be more preferable.
... For performing the measurements, the texture analyzer probe was driven to contact the extruded dough surface. The force required for separating the probe from the dough surface was recorded as a force-time-distance regression ( Figure 3) and calculated as the three values positive maximum force, positive area and distance, which can be interpreted as the attributes "stickiness" (N), "work of adhesion" (NÁmm), and "sample cohesion/dough strength" (mm) (Abebe, Ronda, Villanueva, & Collar, 2015;Chen & Hoseney, 1995a;Grausgruber et al., 2003;Yildiz et al., 2012). Triplicate determinations with each 10 single measurements were carried out (n = 30). ...
... Comparing the force peak results with earlier work, where dough systems from different flour samples, partly fractionation tests and the variation of water content were studied, a higher value range from 0.11 to 2.72 N (partly converted from gram-force) has been obtained (Abebe et al., 2015;Chen & Hoseney, 1994, 1995bGrausgruber et al., 2003;Huang & Hoseney, 1999;Jekle & Becker, 2011;Wang et al., 2022;Yildiz et al., 2012). This was expected since a much wider range of different doughs was analyzed. ...
... This was expected since a much wider range of different doughs was analyzed. The reported distances ranged from 2.01 to 3.08 mm (Grausgruber et al., 2003), 0.01 to 0.11 mm (Jekle & Becker, 2011), 0.62 to 1.22 mm (Yildiz et al., 2012), and from 2.54 to 4.39 mm (Abebe et al., 2015). In this study, distances of 1.27-1.85 ...
Undesired dough adhesion is still a challenge during the production of baked goods. There are various methods for determining the adhesive texture properties of dough. In the majority of scientific papers, dough stickiness is measured analytically by the force-distance recording of dough detachment. In this study, we describe a new multi-scale approach to compare dough adhesion phenomena in a laboratory, pilot sale and human sensory assessment. In it, the adhesive material properties of dough were investigated using a pilot scale toppling device representing dough adhesion behavior in the production process, in the laboratory by texture analysis with the Chen-Hoseney method and furthermore with a new, implemented non-oral human sensory analysis. To simulate different dough adhesion behavior, the dough mechanical and adhesion properties were varied by applying dough-modifying enzymes and different dough storage times. The structural changes in the different wheat dough system were compared by rheological characterization. By characterizing the different adhesion phenomena of the doughs, the sample with bacterial xylanase showed the highest values after 80 minutes of storage time in all three methods. Correlation analysis revealed a strong relationship between the detachment time (pilot scale) and human sensory assessment attributes (Force R=0.81, Time R=0.87, Distance R=0.92, Stickiness R=0.8) after 80 minutes of storage time. Even though human sensory assessment showed limits in the detectability of differences in dough adhesion behavior compared to the Chen-Hoseney method, it was better suited to predict machinability.
... The incorporation of cereal-or fruit-based dietary fibre in wheat dough is known to reduce the hydration rate of the wheat proteins and, as a consequence, to weaken the gluten network (Abebe et al., 2015;Correa et al., 2010;Wang et al., 2002). The consequence of incompletely hydrated gluten is an underdeveloped dough with reduced extensibility. ...
... The consequence of incompletely hydrated gluten is an underdeveloped dough with reduced extensibility. Insoluble dietary fibre compounds such as cellulose and lignin are mainly responsible for the disruption of the protein films (Abebe et al., 2015), as they can act as physical barrier and constrain water absorption of gluten (B arcenas et al., 2009). It has been suggested that an incomplete hydration of wheat proteins and fibre derives from chemical interactions between these two dough components (Chen et al., 1988). ...
... All doughs showed typical viscoelastic creep-recovery behaviour at 25 C, with an increasing strain under the applied stress and partial reformation after stress removal (Abebe et al., 2015). The results of fitting the compliance to the Burgers model (Eqs. ...
The incorporation of dried black currant pomace (BCP) in wheat dough is a possible way to increase the sustainability of the production chain by adding value to a by-product from juice processing that is up to now regarded as waste. The partial replacement of wheat flour by dried black currant pomace (BCP) increased the water absorption of dough and dough development time. Small strain oscillatory rheology showed that dough stiffness increased with increasing levels of pomace addition (G’ at 1 Hz was 8.2 kPa for the reference, and 49.7 kPa for dough with 30% BCP). This result is supported by the higher dough stability observed in farinograms. After simulated baking, dough with 30% BCP showed higher storage and loss moduli compared to the reference and to dough with lower levels of BCP. The increased structural strength that comes with increasing pomace levels is explained by interactions with gluten matrix through hydrogen bonds. The gluten is less developed through the existence of BCP which results in a lower stickiness, resistance and extensibility of the dough. Scanning electron microscopy and fluorescence light microscopy images showed the disruption of gluten film by fibre incorporation. Considering those influences on dough properties, it can be reasoned that dough with 10% BCP would produce products with satisfying characteristics, whereas higher application levels cannot be recommended without using additives to increase the gluten strength.
... The data from creep tests can be modeled to the 4-parameter Burgers model (a Maxwell body in series with one KelvinÀVoigt body) (Abebe et al., 2015;Juszczak et al., 2012;Lazaridou et al., 2007;Ronda et al., 2014Ronda et al., , 2015Villanueva et al. 2021;Witczak et al., 2010) given by ...
... This test can be conducted with a texture meter such as a TA-XT2 or equivalent provided with an Stable Micro Systems (SMS)/Chen-Hoseney device where the sample is placed, and a methacrylate 25 mm cylinder (P/25 P) used as a compression cell (Armero and Collar, 1997;Bollaín et al., 2006;Abebe et al., 2015;Grausgruber et al., 2003;Ronda et al., 2011). The stickiness of the dough can be determined at a pretest and test speed of 0.5 mm/s, 40 g force, and a posttest speed of 10.0 mm/s. ...
Celiac patients cannot consume food containing gluten, so it becomes a challenge for the food industry to develop bakery products without gluten. Limited information is available on the rheological characteristics of gluten-free (GF) doughs. Unlike wheat flour dough, GF dough has poor rheological properties and is difficult to handle for molding and sheeting. In this chapter, rheological measurements applied to the GF dough and associated limitations are presented. Effect of ingredients on GF dough rheology and how dough rheology affects the quality of bread are also discussed. The design of GF breads remains an empirical task, but some conclusions can be drawn from all the rheological and quality studies. The best-developed breads are obtained from doughs not too strong or too weak. Pasting properties and other physicochemical and structural properties of GF matrices also affect the physical quality of the final bread.
... Previous studies demonstrated that the physico-chemical and nutritional quality of tef flours and products formulated from them are importantly affected by the type of tef variety [12][13][14][15]. Analysis done on gel viscoelastic properties of three tef varieties, DZ-Cr-37, DZ-Cr-387 and DZ-01-99, at five incorporation rates, 6, 8, 10, 12 and 14% w/w, revealed that gels made from DZ-01-99 had higher elastic and viscous moduli and tolerated higher shear stress without breaking [16] than the gels made from the other two varieties. ...
... They also found higher flavonoids content and anti-radical activity in the bread enriched with DZ-01-99 (brown tef) flour. On the other side, wheat bread doughs supplemented with the DZ-Cr-37 variety exhibited the highest elastic and viscous moduli, the lowest compliances and the highest steady state viscosity and led to significantly lower volume of bread [13]. Our recent study demonstrated the procedure to make technologically feasible and sensorially acceptable gluten-free bread from tef flour [15]. ...
Tef is currently being incorporated into a wide range of foodstuff due to its high nutritional profile. This study tries to fill the information gap on the effect of tef varieties on physico-chemical, nutritional and sensorial quality of gluten-free bread. Maize starch replacement at 50, 75 and 100 g/100 g level by tef flour from three Ethiopian varieties (DZ-Cr-37, DZ-Cr-387 and DZ-01-99) resulted in viable gluten-free breads with acceptable sensory properties, higher mineral content and lower glycemic response. Tef cultivar type and blending level significantly affected bread quality. The 50% and 75% substitution levels and the DZ-Cr-37 variety led to the highest bread volumes with the lowest firmness. Breads made with DZ-01-99 variety were darker and with more reddish crust and crumb hues than those made with the other varieties. Breads from 100% DZ-Cr-37 achieved the highest hedonic scores for color, odor, taste and texture. The Ca, Fe and Mg contents of the breads made with 100% tef were 13, 40 and 30 times, respectively, higher than those of the control bread (100% maize starch), indicating tef could be used as an excellent source of these important minerals. In addition, the rapidly digestible starch content decreased up to 28% in breads fortified with tef flour.
... Previous studies demonstrated that the physico-chemical and nutritional quality of tef flours and products formulated from them are importantly affected by the type of tef variety [12][13][14][15]. Analysis done on gel viscoelastic properties of three tef varieties, DZ-Cr-37, DZ-Cr-387 and DZ-01-99, at five incorporation rates, 6, 8, 10, 12 and 14% w/w, revealed that gels made from DZ-01-99 had higher elastic and viscous moduli and tolerated higher shear stress without breaking [16] than the gels made from the other two varieties. ...
... They also found higher flavonoids content and anti-radical activity in the bread enriched with DZ-01-99 (brown tef) flour. On the other side, wheat bread doughs supplemented with the DZ-Cr-37 variety exhibited the highest elastic and viscous moduli, the lowest compliances and the highest steady state viscosity and led to significantly lower volume of bread [13]. Our recent study demonstrated the procedure to make technologically feasible and sensorially acceptable gluten-free bread from tef flour [15]. ...
Single and double high hydrostatic pressure (HHP) cycles combined with soaking pre-treatment were applied on buckwheat (BW) whole-grain to enhance the nutritional, functional and bioactive properties of BW flour. Results showed modifications in the microstructure of pre-soaked and HHP treated samples which were associated with the appearance of disruptions on the surface of the starch granules. Combined treatments significantly (p < 0.05) affected the ability of the flours to produce a stable emulsion or foam layer. These treatments also resulted in a significant decrease (p < 0.05) in the gelatinization enthalpy and in the peak viscosity of the flours, while increasing their stability versus heating and shearing. Combined treatments also enhanced significantly (p < 0.05) the antioxidant properties with an increase of phenol content from 311mg GAE/100g in native flour to 361 and 347 mg GAE/100g in pre-soaked and HHP-treated samples at single and double cycle, respectively. Moreover, those samples also exhibited higher minerals retention than un-soaked ones. The data obtained from this study demonstrated the efficiency of the application of combined soaking and HHP treatments on BW grains to enhance the nutritional and functional response of resulting BW flours providing a value-added ingredient with interest in the gluten-free baked goods industry.
... Our findings show that T1 (100% wheat flour) had lower volume (1.87 cm 3 /g −1 ) than T2 (2.27 cm 3 /g −1 ), T3 (2.5 cm 3 /g −1 ), and T4 (2.18 cm 3 /g −1 ). Abebe, Ronda, Villanueva, Collar (2015) found different results regarding volume: their 40% teff flour sample presented lower volume than the treatment with 100% of wheat flour. Hofmanová et al. (2014) also obtained a different outcome from ours: the specific volume of their wheat breads decreased about one-tenth compared to the less fortified one at 20% and fell up to a half when 30% of wheat flour was replaced by teff flour. ...
... However, this study does not corroborate to our results, as the teff treatments presented lower crust firmness than T1 (control, 100% wheat flour). Abebe et al. (2015) assessed breads made with up to 30% teff flour and obtained greater values for dough firmness. The incorporation of up .0 ± 0.1 a 9.0 ± 0.2 a b* 18.4 ± 0.6 a 8.0 ± 0.2 d 9.1 ± 0.1 c 10.2 ± 0.2 b Crust Color L 49.8 ± 5.1 a 32.1 ± 1.3 b 33.2 ± 1.9 b 29.6 ± 2.0 b a* 16.5 ± 1.5 a 12.0 ± 0.9 b 13.1 ± 0.0 b 13.3 ± 0.7 b b* 18.8 ± 0.4 a 10.0 ± 0.6 b 11.6 ± 0.3 b 9.9 ± 1.0 b Crumb firmness (g, force) ...
Objectives
This study aimed to evaluate technological parameters of high fiber and gluten-free breads made with teff (Eragrostis tef) and associated flours.
Methods
Four formulations were evaluated: T1, without teff (100% wheat flour- standard); T2, with 100% teff flour; T3, with 75% teff flour, 12.5% rice flour, and 12.5% cassava starch, and T4, with 50% teff flour, 25% rice flour, and 25% cassava starch. Hardness was verified using a texturometer TA.XT plus and a cylindrical probe with a 36 mm radius, by compressions performed on 12 slices of 2 cm thick and three replicates. The maximum force was determined in the first compression cycle and defined from the following conditions: cylindrical texturometer, maximum test speed of 4.0 mm/s; minimum test speed of 0.01 mm/s; rupture distance of 0.001 mm. The other rheological parameters such as: elasticity, cohesiveness, resilience, chewiness and gumminess were calculated. The results were evaluated
through analysis of variance, followed by Tukey test, 5%, SPSS Statistics, version 21.0.
Results
The crust hardness in T1 was significantly (F = 33.09; p < 0.0001) higher (188g, force) than the other samples: T2 (48 g, force), T3 (40g, force) and T4 (59g, force), which were comparable to each other. Regarding crumb hardness it was observed that T1 showed significant (F = 6.20; p < 0.05) higher hardness compared to T3 (1681 g, force) and T4 (1716 g, force) and was comparable to T2 (2188g, force). The crumb elasticity was significantly (F = 27.0, p < 0.0001) higher in T2 (1.10 mm), T3 (1.10 mm) and T4 (1.10 mm) compared to T1 (1.07 mm). Cohesiveness was the unique rheological parameter that it was observed to change among the breads made with teff. The crumb resilience, chewiness and gumminess were significantly higher in T1 (F = 16.31, p < 0.05; F = 25.69, p < 0.0001; F = 29.04, p < 0.0001, respectively) than bread samples with teff. In relation to pH results it can be observed that T1 (5.8) was significantly more acid (F = 95.4, p < 0.0001), than the other samples.
Conclusions
Teff has shown promising behavior as a new ingredient in food formulation in order to face the worldwide increasing celiac disease. The results suggest that it is possible to develop new gluten-free bakery products using teff flour without decreasing technological quality.
Funding Sources
We are grateful to UFRGS, CNPq and CAPES for providing scholarship to our researchers.
... The extensibility of wheat flour enriched with grape peels decreased with the added amount increase due to the high content of fibers (Bender et al., 2017). The gluten development was negatively influenced by the fiber from fruit processing byproducts, resulting in less extensible dough because they reduce the hydration rate of the wheat proteins, leading to gluten network weakening (Abebe, Ronda, Villanueva, & Collar, 2015). The protein films are damaged by the presence of DFs such as cellulose and lignin, which may create a physical barrier and can affect the water absorption capacity of gluten (Abebe et al., 2015). ...
... The gluten development was negatively influenced by the fiber from fruit processing byproducts, resulting in less extensible dough because they reduce the hydration rate of the wheat proteins, leading to gluten network weakening (Abebe, Ronda, Villanueva, & Collar, 2015). The protein films are damaged by the presence of DFs such as cellulose and lignin, which may create a physical barrier and can affect the water absorption capacity of gluten (Abebe et al., 2015). A better dough resistance to deformation was reported and can be attributed to the high soluble fiber content, which leads to a higher water retention capacity (Bender et al., 2017;Fu, Wang, & Dupuis, 2017). ...
Wine making industry generates high quantities of valuable byproducts that can be used to enhance foods in order to diminish the environmental impact and to obtain more economic benefits. Grape byproducts are rich in phenolic compounds and dietary fiber, which make them suitable to improve the nutritional value of bakery, pastry, and pasta products. The viscoelastic behavior of dough and the textural and the sensory characteristics of baked goods and pasta containing grape byproducts depend on the addition level and particle size. Thus, an optimal dose of a finer grape byproducts flour must be found in order to minimize the negative effects such as low loaf volume and undesirable sensory and textural characteristics they may have on the final product quality. In the same time, an enrichment of the nutritional and functional value of the product by increasing the fiber and antioxidant compounds contents is desired. The aim of this review was to summarize the effects of the chemical components of grape byproducts on the nutritional, functional, rheological, textural, physical, and sensory characteristics of the baked goods and pasta. Further researches about the impact of foods enriched with grape byproducts on the human health, about molecular interactions between components, and about the effects of grape pomace compounds on the shelf life of baked goods and pasta are recommended.
... Our findings show that T1 (100% wheat flour) had lower volume (1.87 cm 3 /g −1 ) than T2 (2.27 cm 3 /g −1 ), T3 (2.5 cm 3 /g −1 ), and T4 (2.18 cm 3 /g −1 ). Abebe, Ronda, Villanueva, Collar (2015) found different results regarding volume: their 40% teff flour sample presented lower volume than the treatment with 100% of wheat flour. Hofmanová et al. (2014) also obtained a different outcome from ours: the specific volume of their wheat breads decreased about one-tenth compared to the less fortified one at 20% and fell up to a half when 30% of wheat flour was replaced by teff flour. ...
... However, this study does not corroborate to our results, as the teff treatments presented lower crust firmness than T1 (control, 100% wheat flour). Abebe et al. (2015) assessed breads made with up to 30% teff flour and obtained greater values for dough firmness. The incorporation of up .0 ± 0.1 a 9.0 ± 0.2 a b* 18.4 ± 0.6 a 8.0 ± 0.2 d 9.1 ± 0.1 c 10.2 ± 0.2 b Crust Color L 49.8 ± 5.1 a 32.1 ± 1.3 b 33.2 ± 1.9 b 29.6 ± 2.0 b a* 16.5 ± 1.5 a 12.0 ± 0.9 b 13.1 ± 0.0 b 13.3 ± 0.7 b b* 18.8 ± 0.4 a 10.0 ± 0.6 b 11.6 ± 0.3 b 9.9 ± 1.0 b Crumb firmness (g, force) ...
Teff is a gluten-free grain and has interesting nutritional composition. This paper aimed to evaluate the differences among breads made with teff flour associated to other components, by determining their chemical and physical characteristics. The breads were as follows: T1—100% wheat; T2—100% teff; T3—75% teff and 12.5% cassava starch; T4—50% teff, 25% rice flour, and 25% cassava starch. The lipid and protein contents in teff breads were like wheat breads. T1 had significantly lower total fiber (13.9%) than the others. The highest amino acid content was found in T4; however, all teff treatments presented higher quantities of amino acids than wheat formulation. T1 had lower volume (1.87 cm³/g⁻¹) than T2, T3, and T4. Teff demonstrated no difference in height, weight loss, yield, and apparent volume of the breads, although it presented lower weight, higher specific volume, and lower crust luminosities. Firmness was directly related to the quantity of teff used.
... The results of creep-recovery measurements are expressed as compliance, which corresponds to the strain divided by the imposed shear stress of 50 Pa. Also, the ratio between the compliance value at the end of the recovery phase (180 s) and the maximum creep compliance value reached in the creep phase for the 60 s was determined, as recovery percent, Recovery (%) = Jr max /Jc max (Abebe et al., 2015). The experiments were conducted in at least two replications for each sample formulated. ...
... The results of creep-recovery measurements for the composite flour with GSF from two variety revealed similar viscoelastic behaviours to that of pure wheat dough, exhibiting an increasing strain under the applied stress and partial reformation after stress removal (Abebe et al., 2015). The creep phase comprise instantaneous elastic (1), retarded elastic (2) and viscous deformation (3), while the recovery phase, includes instantaneous elastic recovery (4) and retarded elastic recovery (5) (Figure 3). ...
In the present study, the influence of grape seeds flour (GSF) addition on the physico-chemical and white wheat flour dough rheological properties were investigated. GSF of two grape varieties, white and red, was added at three particle sizes (L, M and S) and different addition levels (0, 3, 5, 7, 9%) to the white wheat flour. The fundamental rheological properties were investigated by applying oscillatory tests using a dynamic rheometer. The storage (G’) and loss (G”) moduli in function of frequency and temperature respectively, were measured. Creep-recovery tests were also applied to evaluate grape peels-wheat flour dough behaviour. The results showed that the GSF incorporation increased protein content and alpha-amylase activity in composite flour with particle size decrease, affecting gelatization temperature. The changes in dough viscoelasticity depend on the particle size, addition level and grape variety, factors which affected dough capacity to deform. The effects of GSF from white grape were more pronounced compared to GSF from red grape variety. GSF addition exhibited an increase in values of both dynamic moduli, which was more pronounced for the white variety than for the red one. The knowledge of this information is useful in new products development, especially for bakery products manufactory.
... The data from creep tests can be modeled to the 4-parameter Burgers model (a Maxwell body in series with one Kelvin-Voigt body) (Lazaridou et al., 2007;Witczak et al., 2010;Juszczak et al., 2012;Ronda et al., 2014Ronda et al., , 2015Abebe et al., 2015) given by ...
... This test can be conducted with a texturemeter such as a TA-XT2 or equivalent provided with a SMS/Chen-Hoseney device where the sample is placed, and a methacrylate 25 mm cylinder (P/25P) used as a compression cell (Armero and Collar, 1997;Grausgruber et al., 2003;Bollain et al., 2006;Abebe et al., 2015;Ronda et al., 2011). The stickiness of the dough can be determined at pretest and test speed of 0.5 mm/s, 40 g force and a posttest speed of 10.0 mm/s. ...
Little information has been published on the rheological characteristics of gluten-free doughs which greatly vary in consistency, going from batter to dough. The relationships between dough rheology and dough structure and the link between the rheological properties of dough and its behavior during mechanical handling and baking still need to be studied in gluten-free systems. The most frequently used rheological methods applied to gluten-free dough will be presented and briefly explained in this chapter. An overview of the main factors affecting dough rheology and the effect of some common ingredients of gluten-free doughs and how the dough rheology may affect the quality of bread will also be discussed. The design of gluten-free breads remains an empirical task but some conclusions can be drawn from all the rheological and quality studies. The best developed breads were obtained from doughs not too strong or too weak. Nevertheless, consistency seems not to be the sole issue. Pasting properties and other physico-chemical and structural properties of GF matrices also affect the physical quality of the final bread. The high complexity and variability of ingredients used in GF breadmaking, their different nature and properties, are probably responsible for the difficulty of finding a good predictor of bread quality based only in dough rheology.
... The difference in dough creep properties can be explained by the difference in the strength of the network formed by the non-covalent molecules between the gluten chains as a result of the linkage interaction. J e /J max and J v /J max can be interpreted as the relative elasticity and viscosity of the dough's maximum creep flexibility, reflecting the dough's ability to return to its original form (Workineh et al., 2015). The results showed that there was almost no difference in the ability of dough to recover. ...
This study investigated the potential of six wheat flour mixing schemes for reducing the oil content of fried dough sticks and provided a new idea for the production of special wheat flour. The results showed that the FP‐4, FP‐5 and FP‐6 mixing schemes showed some degree of oil reduction, while the FP‐1, FP‐2 and FP‐3 mixing schemes did not perform well in terms of oil reduction. Overall, the compounded wheat flour with relatively high‐protein content had a good oil reduction effect. Dough with higher water absorption, longer development time, stability time and higher deformation capacity had a denser gluten network structure, which was attributed to the presence of membranes in the gluten structure that acted as a barrier to the intrusion of oil. The principal component analysis results also showed that FP‐5 and FP‐6 had relatively high overall scores and had better dough characteristics that were conducive to the reduction of oil content in fried dough sticks. To some extent, the wheat flour mixing scheme proposed in the study has a positive effect on the reduction of oil content in fried dough sticks and can be used as a data reference for the development of low‐fat fried dough sticks.
... Teff, on the other hand, is less accessible and affordable to all members of the country's society and thus is primarily consumed in metropolitan areas where family income is higher (Berhane et al., 2011). Nowadays, teff became increasingly well-known outside Ethiopia due to its lack of gluten and nutritional value which worsen the price of teff in the local market (Abebe et al., 2015;Baye et al., 2014). ...
Injera is Ethiopian fermented and leavened flat bread mainly made from teff flour. For improving
the protein content and sensory quality of injera, the flours are enriched with fenugreek. Injera
made from sorghum flour alone or its blend, however, has noted shortcomings in qualities when
compared to teff injera qualities. Therefore this study was carried out to investigate the effects of
teff-sorghum - fenugreek flour blending ratios on quality attributes of injera and to optimize the
blending ratios of teff, sorghum, and fenugreek flours that give better quality attributes of injera
made from these flour formulations. The effects of blending flour ratios on injera quality were
investigated using mixture design methodology with a D-optimal design. Fourteen formulations
of injera were produced from constrained blends of sorghum (0–50%), teff (50–100%), and
fenugreek (0–5%), while a teff flour alone (100% teff flour) injera was served as control. Analyses
of response parameters were made using the AACC and AOAC standard methods. Response
variables considered in this study were staling rate, proximate, mineral, antinutritional factors and
sensory attributes. Proximate compositions (g/100 g) ranged from 56.16 to 69.92 (moisture), 2.64
to 3.91 (ash), 11.36 to 17.19 (protein), 2.258 to 10.838 (fat), 4.179 to 6.988 (fiber) and 59.54 to
77.74 (carbohydrate), and energy, 348.1-385.62 (kcal/100g). Minerals (mg/100 g) varied from Fe:
12.83 to 21.23, Zn: 1.19–2.36, and Ca: 75.26 to 151.13. Antinutritional factors (mg/100 g) varied
from 4.106 to0.449 (condensed tannin), 72.83 to 174.84 (phytic acid). Sensory scores for sourness,
sweetness, bitterness, softness, stickness, rollability, odour, flavor, eye distribution, color and
overall acceptability were 5.00-6.37, 5.14-6.36, 5.24-6.29, 5.14-6.57, 5.14-6.43, 5.93-6.57, 5.57-
6.57, 5.43-6.71, 5.49-6.43, 4.87-6.29 and 5.60-6.23, respectively.3.670 to 4.105(pH) and staling
rate (%) varies from 8.95 to 33.43, 9.52 to 34.58, and 12.32 to 52.31 after 24,48 and 72hours,
respectively. Alkaline water retention capacity, AWRC (%) varies from 49.42 to 84.01(at zero
time), 32.92 to76.49 (after 24 hr), 32.64 to76.01 (after 48 hr), 23.57 to 73.66 (after 72 hr),
respectively. Results showed that quality attributes were mainly affected by ingredients and it is
possible to prepare better quality attribute injera with a significant fenugreek enrichment without
compromising its acceptability by adding in appropriate flour blending ratios. The best blending
ratio of injera in terms of overall quality attributes was found 64.1% teff, 32% sorghum and 3.80%
fenugreek
... The substitution levels of 10 and 20% resulted in decrease of dough stickiness, while 30 and 40% resulted in increase of dough stickiness in comparison to control dough.Abebe, Ronda, Villanueva, & Collar, 2015 ...
This review presents integrated literature data on the occurrence and type of dietary fibres present in cereals and pseudocereals, as well as their technological role in production of wheat based dough and bread. The focus on wheat based dough and bread was in order to objectively compare the influence of the fibre and flour fractions of cereals and pseudocereals on the same food matrix. The evident heterogeneity, contradiction of scientific results and the lack of objective comparability were the main reason for compilation of systematic review. Remarkably, the literature is characterized by a large methodology gap that leads to significant knowledge gap due to the lack of the comparability of presented results on dietary fibre content, composition and influence on wheat based dough and bread properties. Based on this, the authors must emphasize the need for standardized presentation of scientific results in the future by scientific community.
... The absence of gluten and its nutritional value made tef increasingly well-known and attractive outside Ethiopia. Among the expanding segments of health-conscious consumers, teff is marketed by various sellers as a unique and healthy alternative to more common staples like wheat (Abebe et al. 2015;Baye et al. 2014). These resulted in an escalation of the price of the teff grain, making it currently the most expensive grain in Ethiopia. ...
... The absence of gluten and its nutritional value made tef increasingly well-known and attractive outside Ethiopia. Among the expanding segments of health-conscious consumers, teff is marketed by various sellers as a unique and healthy alternative to more common staples like wheat (Abebe et al. 2015;Baye et al. 2014). These resulted in an escalation of the price of the teff grain, making it currently the most expensive grain in Ethiopia. ...
Teff is an important food crop in Ethiopia and mainly used for the production of injera, a flatbread considered the country’s national dish. But due to increasing demand of teff it is important to look for alternative crops that can contribute to food security. Oat and fenugreek are crops known for their health benefits but are still mainly used for animal nutrition in Ethiopia. The objective of this work was to quantify the proximate composition, nutrients, and amino acid compositions of local teff, oat, and fenugreek varieties in order to create suitable blends for injera making. At about 65%, the carbohydrate content in oat and teff was about twice as high as for fenugreek. However, fenugreek had a higher level of crude protein (about 32%) than teff (12%) and oat (14%), which makes it an important supplement for cereal grains. The concentration of macronutrients also depended greatly on the cultivated crop, with the highest iron concentrations found in teff and highest calcium and potassium concentrations in fenugreek. All essential (exception methionine) and nonessential amino acids were found to be highest in fenugreek with relatively small variations between the varieties. Teff and oat contained lower levels with clear differences between the varieties. Low contents of amino acids were mostly found for the teff variety DZ-Cr-387 and high values for the oat variety Jarsey. The study showed that oat blended with fenugreek could substitute teff grain for injera making. The chemical composition of the varieties should also be considered when blending these components.
... Tef cultivars are most commonly classified in terms of their brown or white seed color, and rarely according to their specific variety (Sliwinski, Hopfer, & Ziegler, 2019). However, the physico-chemical and nutritional quality of tef flour and their derived products are highly dependent on the variety Abebe, Ronda, Villanueva, & Collar, 2015;Bultosa & Taylor, 2004). Although tef grain/flour characterization and their food applications are extensively studied, little information is available about the impact of tef incorporation in GF bread formulations depending on the variety. ...
Tef flour has been considered a good alternative raw material to improve the quality of gluten-free bread due to its attractive nutritional profile. The influence of tef variety (DZ-Cr-37, DZ-Cr-387 and DZ-01-99) and incorporation level (100, 75 and 50%) on rheological and thermal properties of maize starch-based gluten-free doughs, and their impact on bread characteristics was investigated. The addition of tef brought about a structuring effect of doughs leading to higher viscoelastic moduli and steady-state viscosities and to lower tan δ values and instantaneous and retarded compliances. These effects were magnified with the increase of tef level in the dough. Tef addition led to an increase in dough gelatinization temperature and a decrease of gelatinization enthalpy, especially in the case of DZ-01-99 variety. Tef incorporation at 50 and 75% level led to well-developed bread which volume and crumb grain properties were significantly affected by the tef variety. DZ-Cr-37 variety led to the highest bread volume but to a less regular and poorer crumb grain. However, the bread made with 100% DZ-Cr-37 reached the highest overall acceptance score. This work demonstrates tef flour incorporation up to 100% level is a feasible procedure to reach technologically viable and sensory acceptable gluten-free bread.
... The recovery compliance, J r (Pa −1 ), evaluated where dough recovery reached equilibrium, is calculated by the sum of J Ro and J Rm . The relative elastic part of the maximum creep compliance, expressed as percent recovery was determined using Equation (6) [42,43]: ...
The rheological and microstructural aspects of the dough samples prepared from wheat flour and different levels of tomato seed flour (TSF) were investigated by rheology methods through the Mixolab device, dynamic rheology and epifluorescence light microscopy (EFLM). The Mixolab results indicated that replacing wheat flour with TSF increased dough development time, stability, and viscosity during the initial heating-cooling cycle and decreased alpha amylase activity. The dynamic rheological data showed that the storage modulus G’ and loss modulus G” increased with the level of TSF addition. Creep-recovery tests of the samples indicated that dough elastic recovery was in a high percentage after stress removal for all the samples in which TSF was incorporated in wheat flour. Using EFLM all the samples seemed homogeneous showing a compact dough matrix structure. The parameters measured with Mixolab during mixing were in agreement with the dynamic rheological data and in accordance with the EFLM structure images. These results are useful for bakery producers in order to develop new products in which tomato seed flour may be incorporated especially for wheat flours of a good quality for bread making and high wet gluten content. The addition of TSF may have a strength effect on the dough system and will increase the nutritional value of the bakery products.
... En la zona "plateau" del espectro, se pueden utilizar ecuaciones empíricas más sencillas para reproducir los resultados experimentales de los módulos dinámicos en función de la frecuencia como por ejemplo, Basu et al. (2011) en su estudio de sustitución de sucrosa por sorbitol en mermeladas yAbebe et al.(2015)en el análisis comparativo de pastas de harinas. ...
The objective of this work is the study of the cosmetotechnic of toothpastes and in particular their most relevant rheological aspects.
... This can be explained by the competition for available water in dough system which leads to an inevitable decrease in extensibility, a predictor of the processing prop- This can be associated with the low solubility and strong waterholding capacity of the dietary fibers from GPF. A similar trend for fiber-enriched dough was earlier reported by other authors (Abebe, Ronda, Villanueva, & Collar, 2015;Ahmed et al., 2013;Ghoshal & Mehta, 2019;Mironeasa et al., 2019;Singh, Liu, & Vaughn, 2013). ...
The valorization of grape peels by‐product to supplement wheat bread has immense potential, particularly in refined wheat flour (RWF) to increase the dietary fibers. The main aims of this study were successful modeling of dough rheological properties using predictive models, investigating the effect of factors, grape peels flour (GPF) variety, level and particle size (PS) of GPF added in RWF on responses, and finally, optimizing the formulation with respect to dough rheological behavior. The rheological properties of grape peels–wheat composite flour formulated with GPF from two variety and increasing levels of GPF (0–9%) in the presence of different PS (large, L > 500 μm; medium, 200 μm > M < 500 μm, and small, S < 200 μm) of GPF was evaluated using farinograph, alveograph, and dynamic oscillation measurements. The artificial neural network models (R ² > .82) developed to predict dough rheological properties highlighted an improved estimation and predictive capabilities compared with response surface methodology models (R ² > .77). The multiobjective optimization approach allowed anticipation of the optimal value for each response in terms of dough rheological properties as function of GPF from white variety of small PS, which replaced RWF at level of 3.81%.
Practical applications
In the composite flour formulation to produce effectiveness and nutritive bread, optimizing dough rheology in relation to the formulation factors represents the actual need for the bread‐making industry. Dough behavior during mixing (water absorption, dough stability, dough development time, and degree of softening), alveograph parameters (dough tenacity, extensibility, and deformation energy), and dynamic rheological properties (elastic modulus, viscous modulus, loss tangent, and complex viscosity) are considered essential to optimization of grape peels–wheat composite flour formulation. The current study revealed the efficacy of modeling and optimization between response surface and artificial neural network techniques for the grape peels–wheat flour dough rheological properties. The information given from this study would help the industry to develop new bread‐making products with the desired particle size with optimum functional and nutritional properties.
... The recovery compliance, J r (Pa −1 ), evaluated where dough recovery reached equilibrium, is calculated by the sum of J Ro and J Rm . The relative elastic part of the maximum creep compliance, expressed as percent recovery (Abebe et al. 2015) was determined using the Eq. (6): ...
The present study was undertaken to assess the effects generated by grape peels flour (GPF), as a source of dietary fibers, on the white wheat flour (WF) dough rheological behavior. Dynamic and empirical rheological measurements were carried out in order to study the viscoelasticity of GPF-enriched wheat flour-based dough matrices and to identify the main actions of GPF particle size (large, medium, and small) at replacement levels from 0% up to 9%. The water competition of GPF is explained by different water binding and gelling capacities, synergistic and/or antagonistic effects of GPF compounds on the major rheological properties. Power low and Burgers models were successfully fitted with the dynamic oscillatory and creep-recovery data being suitable to interpret viscoelastic behavior of dough. Composite flour dough with smaller particle size presented higher G′ and G″ values at addition level above 5% GPF, exhibiting higher viscous component with concomitantly higher peak viscosity. Creep-recovery tests for samples with small particle size at 5% addition level showed that the elasticity and the recoverable proportion was higher compared to the rest of GPF formulations and control sample. Significant correlations (p < 0.05) were found between several parameters determined by both dynamic and empirical rheological measurements which have essential roles in monitoring GPF-enriched wheat flour dough in a wide set of different kinds of samples. This information could be helpful to optimize the particle size and addition level of GPF that could be useful to produce GPF-enriched designed bread.
... However, the elimination of the viscoelastic gluten protein represents a major technological challenge, as the wheat protein gluten is essential for structure formation. The gluten matrix is a major determinant of the important rheological characteristics of dough, such as elasticity, extensibility, resistance to stretch, mixing tolerance and gas-holding ability [38]. ...
Teff has naturally higher nutritional value when compared to many other grains, and doesn’t need to be fortified. Naturally gluten-free, the grain of teff can substitute for wheat flour and other cereals in anything from bread and pasta to waffles and pizza bases, as well as foods for people with celiac disease. Thus, the main objective of this article is to review researches on teff, evaluate its suitability for different food applications, and give direction for further research on its applications for gluten free food market. Teff grain size is known to be extremely small with mean length ranging 0.61-1.17mm and it is considered a superior grain due to its nutritional merits. Teff is rich in carbohydrate, fiber and contains more iron, calcium and zinc than other cereal grains, including wheat, barley and sorghum. Teff has an excellent balance of essential amino acids and is a good source of calcium and iron, which may explain the low occurrence of anemia in areas of Ethiopia where to regular teff consumption. Hence, Teff is an ideal and healthy ingredient for many gluten-free recipes.
... The non-endosperm components (germ, bran) exert a dilution effect on the gluten-forming proteins, restrict the water available for gluten hydration and development, or even physically disrupt the starchgluten matrix. Therefore, the addition of nonendosperm components usually reduces the bread volume (Abebe et al. 2015;Li et al, 2015). However, during processing of wholemeal flour, the addition of different plant components increases the gas retention capacity during dough fermentation and the increase of bread volume is observed (Boz and Karaoglu, 2013). ...
Scientific studies have revealed that bioactive components of coffee play a preventive role against various degenerative diseases. Green coffee, in particular, is characterized by its unique composition and properties. The objective of this work was to investigate the influence of green coffee (Coffea arabica) beans (GCB) addition on the quality and antioxidant properties (AA) of the wholemeal bread. For bread preparation, flour form GCB, and wholemeal wheat flour, type 2000 were used. Wholemeal wheat flour was replaced with GCB flour at 1 to 5% levels. Loaf volume, texture, color and sensory properties of bread were determined. Furthermore, total phenolic content and antioxidant activity were evaluated. The results showed that bread supplementation with GCB had little influence on the bread volume. The highest volume of bread was obtained with 3 and 4% of GCB flour. The texture properties of bread crumb (hardness, elasticity, cohesiveness and chewiness) were slightly changed as a result of the GCB addition. The lightness of bread crumb decreased with the GCB addition (average from 46.3 to 42.6). Besides, the addition of GCB significantly enriched wheat bread with hydrophilic phenolic compounds. The phenolic compounds were highly bioaccessible in vitro. Moreover, the GCB addition enhanced antiradical activity of bread.
In recent years, there has been a significant increase in demand for gluten-free foods. This rise can be attributed to a growing number of individuals opting for gluten-free diets due to factors such as gluten sensitivity and celiac disease. Interest in teff has also increased markedly due to its high protein content, balanced amino acid composition, and rich nutrient contents including fiber, iron, and calcium, along with its gluten-free nature. Additionally, teff exhibits positive functional properties that contribute to improving texture, moisture retention, and shelf life in gluten-free products. Its mild flavor profile allows for versatile applications across a spectrum of culinary applications, enhancing the sensory appeal and taste of gluten-free offerings. This makes it a suitable alternative to wheat and other grains in food applications for individuals with celiac disease. Overall, integrating teff into gluten-free formulations presents an attractive opportunity to enhance the nutritional quality, sensory experience, and market competitiveness of gluten-free products, catering to the diverse needs and preferences of consumers seeking gluten-free alternatives for health, dietary, or lifestyle reasons. Further research and innovation in teff-based product development are crucial to fully unlock its potential and promote inclusive, sustainable growth in the gluten-free food sector. Therefore, these attributes underscore teff's promising role in the global food and beverage industries.
Background and Objectives
Intermediate wheatgrass (IWG), a resilient perennial grain with adaptability to difficult climates, is emerging as a compelling candidate for sustainable food solutions in bakery product applications. This study evaluated the pasting and rheological properties of doughs made from bread wheat flour and blended bread wheat–IWG flours (IWG content: 15%, 30%, 45% and 60%), with the goal of exploring the potential of IWG flour as a nutritious and sustainable ingredient in cereal‐based products.
Findings
The RVA peak, trough, and final viscosity values significantly ( p < .05) decreased, and the pasting temperature increased as the IWG substitution level increased. IWG‐containing flour blends had a lower retrogradation tendency compared to the control. As the IWG flour substitution level increased, both empirical (Mixograph, Kieffer dough and gluten extensibility, Glutograph) and fundamental (linear oscillatory frequency sweep and creep–recovery) rheological measurements indicated relatively weaker dough properties imparted by the addition of the IWG flour.
Conclusions
The outcomes of this research will shed light on the impacts of utilizing alternative grains, such as intermediate wheatgrass, in bakery applications. This will provide insights that could inform the development of nutritious and sustainable baked products to meet the demands of health‐conscious consumers.
Significance and Novelty
The dough weakening effect of the IWG flour was tolerated at the 15% IWG flour substitution level. At lower substitution levels, the IWG‐containing flour blends exhibited a lower retrogradation tendency compared to bread wheat flour, which could indicate lower staling of loaves of bread during bread storage without compromising the physical quality of bakery products. Finally, the present research fills a critical gap in the literature as it represents the first application of fundamental rheological methods at known and controlled strain and stresses to evaluate the physical properties of doughs prepared from IWG flour blends.
The chapter reviews the application of creep-recovery and oscillatory rheological tests in flour-based systems, including simple flour-water systems, and more complex ones, such as bread, cookies, and biscuits. A theoretical introduction about the fundaments and methods of linear viscoelastic rheology is presented, including general mathematical models and their application in flour-based systems. A summary of experimental conditions to perform the rheological tests is included. The functionality of flour-based systems is extremely dependent on their viscoelastic properties. Processes like mixing, pumping, lamination, and baking performance are strongly dependent on the system’s viscoelastic properties. However, the establishment of general and well-defined relationships among viscoelastic properties and specific functionalities is quite a difficult task, still in progress.
The objective of this study was to investigate chemical, technological, and sensory quality of tef in products made exclusively with tef flour and tef flour associated with other flours. The selection of the studies and the extraction of information were carried out through research in several databases. Tef flour was used in cakes, cookies, breads, cupcakes, muffins, and extruded snacks. Bread was the most evaluated product with tef flour associated with other flours or exclusively. Most of the outcomes were with tef (5–50%) associated with other flours. Increased levels of fibers, minerals, antioxidant capacity, and flavonoids were noted according to the percentage of tef. Technological characteristics demonstrated that these products showed intermediate final quality, due to the characteristics of volume, specific volume, firmness, and luminosity. Regarding sensory quality, studies that used (5–35%) tef flour associated with other flours were well‐accepted.
At present, there are seldom researches on the application of potassium carbonate in dough. In this paper, the influence mechanism of potassium carbonate on the rheological properties of dough was analyzed by exploring effect of potassium carbonate on the structure and physicochemical properties of starch and protein in the dough. Compared with the control group, the disulfide bond, guache-guache-guache conformation, and β-sheet increased by 1.46 μmol/g, 9.02%, and 5.11%, respectively, when the addition amount of potassium carbonate was 0.6%. It showed that potassium carbonate induced protein aggregation and interaction in the dough which was the main reason for the increase of elasticity and the decrease of extensibility. The results also showed that potassium carbonate (>0.2%) destroyed the ordered structure in starch of dough. Nevertheless, the potassium carbonate had no influence on the crystal form of starch in the dough.
The chapter reviews the application of creep-recovery and oscillatory rheological tests in flour based systems, including simple flour water systems, and more complex ones, such as bread, cookies and biscuits. A theoretical introduction about the fundaments and methods of linear viscoelastic rheology is presented, including general mathematical models and their application in flour based systems. A summary of experimental conditions to perform the rheological tests is covered. Functionality of flour based systems is extremely dependent on their viscoelastic properties. Processes like mixing, pumping, lamination, baking performance have been found to be strongly dependent on the system viscoelastic properties. However, the establishment of general and well-defined relationships among viscoelastic properties and specific functionalities is quite a difficult task, still on progress.
Throughout the process of bakery production, dough stickiness is a widespread problem and is influenced by many factors. Reliable, quick and quantitative methods are needed for measurement of dough stickiness in baking industry. In this study, three different flours were used (F1, F2 and F3) and 12% wheat starch and 2% vital gluten were added to those flours to widen protein content of each flour sample. Stickiness values of prepared doughs were measured using SMS/Chen-Hoseney unit at different resting times (0, 20 and 40 mins). Stickiness (g), work of adhesion (g.s) and dough strength/cohesivenes (mm) values were measured for comparison. Obtained data from dough with F1 was significantly different from other flours (P<0.05). Protein content and resting time have changed dough stickiness value. A positive relationship was found between farinograph water absorption and dough stickiness of flour. Stickiness value increased with water uptake of flour.
The impact of acid incorporation (acetic + lactic, 0.5 %) into rice starch-based doughs enriched with different proteins (egg albumin, calcium caseinate, pea and soy protein isolates) at different doses (0, 5 and 10 %) was investigated on dough proofing and thermal properties, and bread quality evaluated from physical and sensory measurements. Proteins from vegetable sources led to breads with lower-specific volume and harder crumb, effects being magnified with protein dose and reduced with acid addition. Incorporation of proteins from animal source resulted in different behaviours according to the protein type, dosage and acidification. Protein addition increased the dough pH and total titratable acidity and reduced the impact of acid addition on dough acidity. Albumin-added doughs had significantly higher temperature of gelatinization than most of the other supplemented doughs, while vegetable proteins led to significantly lower gelatinization enthalpy than the control dough. Acid addition affected dough proofing and significantly improved the volume and texture of protein-enriched breads without detriment of either odour or taste.
The protein fractions in three different teff types were studied in comparison to sorghum to explain teff’s superior bread making quality. The proportion of aqueous alcohol-soluble teff protein was approx 40% and it was rich in glutamine and leucine. Hence, contrary to previous reports, prolamin is the major teff grain storage protein. With SDS-PAGE under non-reducing and reducing conditions, teff prolamins showed broad bands at approx. 20.3 and 22.8kDa. Other bands were at approx. 36.1, 50.2, 66.2 and 90.0kDa, respectively under non-reducing conditions, but were absent under reducing conditions, indicating that these polypeptides are disulphide bonded. The presence of broad monomeric prolamin bands in teff under non-reducing conditions indicates that teff prolamin is less polymerized than sorghum prolamin. Estimated free energy of hydration of teff prolamins was −161.3 kcal/mol compared to −139.8kcal/mol for sorghum prolamin. By 2-D electrophoresis, teff protein contained more polypeptides than maize or sorghum. Teff contained a higher proportion of basic polypeptides than maize. With differential scanning calorimetry, teff prolamin exhibited a single endothermic peak at 69.85°C, while no peak was detected for sorghum prolamin. The lower polymerization, hydrophobicity and denaturation temperature of teff prolamins probably make them somewhat functional in bread making.
Three different flours were examined to study the influence of moisture content on the dynamic viscoelastic behavior of wheat flour dough. Doughs with moisture contents varying from 43 to 58% were submitted to dynamic testing using a mechanical spectrometer operating in frequency sweep mode, obtaining information about rheological response in the linear viscoelastic range. To characterize the influence of moisture content on the dynamic viscoelastic behavior of wheat flour dough, some hypotheses regarding the functional role of the water molecules were verified by applying reduction procedures of the rheological curves. By shifting the rheological curves along the vertical axis, it was possible to verify that varying the moisture content of the doughs not only changed dynamic properties but also modified viscoelastic response. By applying a reduction procedure similar to that used to estimate the constants of the Williams, Landel, and Ferry equation, we demonstrated that not only did the viscoelastic response of doughs vary, but that water molecules interfere with the dynamic by which relaxation phenomena take place. Finally. we proved that the rheological behavior of flour dough is similar to that of concentrated polymer solutions. and that it can be characterized by using a double reduction procedure, shifting the rheological curves along the vertical and horizontal axes, and obtaining a master curve that can be considered inherently characteristic of viscoelastic behavior.
Attenuated total reflectance (ATR) and Fourier transform infrared (FTIR) spectroscopy have been applied in the characterization of sticky dough surfaces. The characterization provides insight in the chemical distribution of gluten protein, starch, water, and fat during dough kneading. ATR is especially useful for selective sampling of dough surfaces because the depth of penetration of radiation is quite shallow. For dough, it is calculated to be in the order of 0.5-4 mum in the mid-infrared, ideal for measurements of stickiness effects, where only the dough surface is of interest. To investigate the cohesive and adhesive properties of the individual dough constituents, dough was peeled from the ATR plate to study the material that adhered to it. The infrared spectra obtained indicate that fat and gluten protein appear to be located at the outer sticky dough surfaces, rather than water and starch. In comparison with gluten, the fatty component showed relatively strong adhesive forces to the ATR plate; a high residual fraction was measured after peeling the dough. Gluten proteins display different cohesion and adhesion properties that are strongly dependent on their hydration state. This indicates that the degree of hydration of gluten proteins contributes to the sticky properties of (overkneaded) dough. When analyzing gluten protein in D2O instead of a dough matrix, more or less similar results were obtained. Significant differences in amide I and amide II intensities were measured for kneaded and stretched gluten protein in comparison to untreated, wet gluten. Besides changes in the vibrational properties of the amide groups, conformational changes in the tertiary protein structure also were observed. It appears that kneading and stretching of dough results in a major decrease in alpha-helices content, accompanied by an increase of extended beta-sheet conformations.
In view of the limited information on tef grain and flour quality factors, 13 tef (Eragrostis tef) grain varieties were characterized for grain physical, proximate%, amylose% and flour starch pasting. The grain length (width) were ranged 1.30 (0.67)-0.51 (0.10) [mean = 1.17 (0.59)-0.61 (0.13)] mm, grain mass retained on 600 + 300 microns were about 98% and thousand kernel weight (TKW, g) were between 0.285-0.241 (mean = 0.264). The % proximate compositions are of typical for tef grain reported elsewhere. Both amylose% [25.8-20.0 (23.0)] and amylograph flour starch pasting showed that no waxy-or amylo-type starch traits in the varieties. The pasting temperature (PT) is high, because tef is a tropical C4 cereal. Tef flour starch showed less thickening ability, more shear tolerance and slow setback compared to maize starch. A variety (DZ-01-1285) with least grain protein (GPC) showed highest peak (PV), cold (CPV) and setback (SB) viscosities. The GPC was negatively weak correlated with PV (r = –0.461, p< 0.01), hot paste viscosity (HPV) r = –0.365 (p< 0.05) and break down (BD) (r = –0.360, p< 0.05) as similar reported for wheat flour starch pasting. Negative correlation (p < 0.01) between amylose%: PT (r = -0.606) and pasting time (Pt) (r = -0.460) were observed as with the normal cereal starches. However, in tef flour starch pasting, a subtle increase in the amylose% was weakly correlated toward increase of amylograph setback viscosity (SB, gelation tendencies) in part probably because of interferences of other flour components on the gelation tendency of amylose.
The effect of hydrocolloids on dough rheology and bread quality parameters in gluten-free formulations based on rice flour, corn starch, and sodium caseinate (control) was studied; the hydrocolloids added at 1% and 2% w/w (rice flour basis) were pectin, carboxymethylcellulose (CMC), agarose, xanthan and oat β-glucan. The study on rheological behavior of the doughs containing hydrocolloids, performed by farinography and rheometry, showed that xanthan had the most pronounced effect on viscoelastic properties yielding strengthened doughs; addition of xanthan to the gluten-free formulation resulted in a farinograph curve typical of wheat flour doughs. Moreover, among the preparations supplemented with hydrocolloids the elasticity and resistance to deformation of dough, as determined by oscillatory and creep measurements, followed the order of xanthan > CMC > pectin > agarose > β-glucan. The type and extent of influence on bread quality was also dependent on the specific hydrocolloid used and its supplementation level. Generally, the volume of breads increased with addition of hydrocolloids except for xanthan; with increasing level of hydrocolloids from 1% to 2% the loaf volume decreased except for pectin. Empirical methods were used for evaluation of porosity and elasticity of the crumb; high values of porosity were found for breads supplemented with CMC and β-glucans at 1% concentration, and pectin at 2%, whereas high crumb elasticity was exhibited by CMC, pectin and xanthan at 2%. An increase in lightness (L value) of crust was observed with the addition of β-glucan at 1%, whereas the whiteness of crumb was improved with inclusion of xanthan. Sensory evaluation by a consumer panel gave the highest score for overall acceptability to the gluten-free formulation supplemented with 2% CMC. In most cases, addition of hydrocolloids did not affect significantly the water activity (aw) values of crumb. During storage of breads a reduction in aw and an increase in firmness of crumb (compression tests) were observed. Compared to the control formulations, crumb firmness was not alter significantly with addition of pectin, CMC and agarose (at 1–2%), and of β-glucan (at 1%); instead, addition of xanthan (1–2%) as well as β-glucan (2%) resulted in crumb hardening.
Starch isolated from five grain tef (Eragrostis tef) varieties was characterized and compared with commercial maize starch. Grain tef starch is formed of compound granules, comprising many polygonal shape (2—6 μm in diameter) simple granules. The crude composition is similar to that of normal native cereal starches. The amylose content ranges from 24.9—31.7%. Gelatinisation temperature range was 68.0—74.0—80.0 °C, typical of tropical cereal starches, and resembling the temperature range of rice starch. The mean intrinsic peak viscosity (269 RVU), breakdown viscosity (79 RVU), cold paste viscosity (292 RVU) and setback viscosity (101 RVU) determined were considerably lower than that of maize starch. Tef starch has higher water absorption index (WAI) (mean 108%) and lower water solubility index (WSI) (mean 0.34%) than maize starch.
Starch isolated from five grain tef (Eragrostis tef) varieties was characterized and compared with commercial maize starch. Grain tef starch is formed of compound granules, comprising many polygonal shape (2-6 μm in diameter) simple granules. The crude composition is similar to that of normal native cereal starches. The amylose content ranges from 24.9 - 31.7%. Gelatinisation temperature range was 68.0-74.0-80.0 °C, typical of tropical cereal starches, and resembling the temperature range of rice starch. The mean intrinsic peak viscosity (269 RVU), breakdown viscosity (79 RVU), cold paste viscosity (292 RVU) and setback viscosity (101 RVU) determined were considerably lower than that of maize starch. Tef starch has higher water absorption index (WAI) (mean 108%) and lower water solubility index (WSI) (mean 0.34%) than maize starch.
The aim of this study was to evaluate the effect of Supplementations of teff (Eragrostis teff (ZUCC.) Trotter) grain flour to wheat flour at 0, 5, 10, 15 and 20% levels on organoleptic and nutritional evaluation of the supplemented bread. Protein, moisture, ash and falling number as well as rheological evaluation were estimated for prepared flour blends and dough. Besides, organoleptic assessment tests for their breads were carried out. Substitution of wheat flour by teff flour caused significant increases in ash and substantial reduction in protein content. Falling Number increased significantly as the percentage of teff flour was increased. However, the results indicated that addition of teff flour caused non-significant increase in water absorption and also, with exception of 15% and 20% substitution of teff flour, no significant change was observed in development time. Data on the gluten quality of flour blends indicated that the gluten contents decreased significantly as the percentage of teff flour substitution increased. Nevertheless, additions of 5% teff flour to wheat flour substitution; gives parameter values at least as good as the control sample and produce acceptable bread, in terms of weight, volume, specific weight, taste and texture. However, high level of teff flour resulted in higher negative changes in organoleptic characteristics. It may be concluded that breads supplemented with teff flour, up to a 5% level, are organoleptically and nutritionally acceptable. Southern Cross Journals
The impact of acid incorporation (acetic + lactic, 0.5%) into rice starch-based doughs enriched with different proteins (egg albumin, calcium caseinate, pea protein and soy protein isolates) at different doses (0, 5 and 10%) has been investigated on dough viscoelastic and pasting profiles. Oscillatory (stress and frequency sweeps) and creep-recovery tests were used to characterize the fundamental viscoelastic behaviour of the doughs, and thermomechanical assays were performed to assess dough viscometric performance. Supplementation of gluten-free doughs with proteins from vegetal sources led to more structured dough matrices (higher viscoelastic moduli and steady viscosities, and lower tan δ, instantaneous and retarded elastic compliances) effect being magnified with protein dose. Acid addition decreased these effects. Incorporation of proteins from animal source resulted in different viscoelastic behaviours according to the protein type, dosage and acidification, especially for casein. Acidification conferred lower dough deformation and notably higher steady viscosity and viscoelastic moduli for 5 %-casein-added dough. Protein-acid interaction favoured higher viscosity profiles, particularly for doughs with proteins of vegetable origin and lower dosage. Dough acidification decreased the pasting temperatures and the amylose retrogradation. Acidification of protein-enriched rice-starch doughs allowed manipulation of its viscometric and rheological properties which is of relevant importance in gluten-free bread development.
The in vitro starch digestibility of five gluten-free breads (from buckwheat, oat, quinoa, sorghum or teff flour) was analysed using a multi-enzyme dialysis system. Hydrolysis indexes (HI) and predicted glycaemic indexes (pGI) were calculated from the area under the curve (AUC; g RSR/100g TAC*min) of reducing sugars released (RSR), and related to that of white wheat bread. Total available carbohydrates (TAC; mg/4 g bread “as eaten”) were highest in sorghum (1634 mg) and oat bread (1384 mg). The AUC was highest for quinoa (3260 g RSR), followed by buckwheat (2377 g RSR) and teff bread (2026 g RSR). Quinoa bread showed highest predicted GI (95). GIs of buckwheat (GI 80), teff (74), sorghum (72) and oat (71) breads were significantly lower. Significantly higher gelatinization temperatures in teff (71 °C) and sorghum flour (69 °C) as determined by differential scanning calorimetry (DSC) correlated with lower pGIs (74 and 72). Larger granule diameters in oat (3–10 μm) and sorghum (6–18 μm) in comparison to quinoa (1.3 μm) and buckwheat flour (3–7 μm) as assessed with scanning electron microscopy resulted in lower specific surface area of starch granules. The data is in agreement with predictions that smaller starch granules result in a higher GI.
An objective method was developed to measure dough stickiness. The texture analyser provided the required compression force and measured the tension. A cell was designed and built that caused the dough to separate from the probe surface under tensile stress. This is critical for the measurement of dough surface stickiness. The procedure was highly reproducible and appeared to correlate well with subjective measurements of dough stickiness. A number of factors that affected dough stickiness were studied by the developed procedure. Although many factors were shown to affect dough stickiness, none appeared to explain the increased stickiness found with certain flours.
The growing interest in the benefits of wholegrain products has resulted in the development of baked products incorporating less utilised and ancient grains such as, millet, quinoa, sorghum and teff. However, addition of wholegrains can have detrimental effects on textural and sensory bread product qualities.Enzymes can be utilised to improve breadmaking performance of wholegrain flours, which do not possess the same visco-elastic properties as refined wheat flour, in order to produce a healthy and consumer acceptable cereal product.The effects of Teff grain on dough and bread quality, selected nutritional properties and the impact of enzymes on physical, textural and sensory properties of straight dough and sourdough Teff breads were investigated.Teff breads were prepared with the replacement of white wheat flour with Teff flour at various levels (0%, 10%, 20%, and 30%) using straight dough and sourdough breadmaking. Different combinations of enzymes, including xylanase and amylase (X + A), amylase and glucose oxidase (A + GO), glucose oxidase and xylanase (GO + X), lipase and amylase (L + A) were used to improve the quality of the highest level Teff breads. A number of physical, textural and sensory properties of the finished products were studied. The nutritional value of breads was determined by measuring chemical composition for iron, total antioxidant capacity, protein, fibre and fat. The obtained results were used to estimates intakes of nutrients and to compare them with DRIs.The incorporation of Teff significantly (P
Texture properties of wheat doughs were determined with a texturometer by using texture profile analysis (TPA) as well as
Chen and Hoseney methodologies. The time elapsed between two compressions and strain were optimized so that meaningful values
were obtained for TPA. Single effects and interactions between flour type, the breadmaking process and anti-staling additives
(i. e. monoglycerides, diacetyl tartaric ester of monoglycerides, sodium stearoyl lactylate, carboxymethylcellulose and hydroxypropylmethylcellulose)
on dough texture properties (i. e. springiness, resilience, hardness, cohesiveness, adhesiveness, chewiness, gumminess and
stickiness) were estimated. The breadmaking process and addition of hydrocolloids had the most important effects and interactions
on TPA. Hydrocolloids and α-amylase increased dough stickiness. Dough cohesiveness was a good predictive parameter of bread
quality. Water content, acidity values and gluten quality were the main factors determining the texture properties of dough.
The rheological properties of two varieties of rice with Hydroxy propyl methyl cellulose (HPMC) added as gluten substitute were studied using a farinograph and a rheometer and compared with wheat dough to find its suitability for making rice bread. The water absorption and dough development time data were obtained from the farinogram. The tests conducted in the rheometer were oscillation measurements (frequency sweep from 0.1 to 20 Hz at 1% strain), shear measurement (shearing from 0.1 to 5 s−1) and creep tests with an instant loading of 50 Pa for 60 S. Baking tests were conducted with all the dough samples and the loaf volume and moisture loss of bread were measured. The farinogram showed that rice flour supplemented with HPMC reached a consistency of 500 BU at a later time than that of standard wheat dough. The rheological measurements from the oscillation tests and creep tests showed that the rice dough with 1.5% and 3.0% HPMC had similar rheological properties to that of wheat flour dough and was suitable for making rice bread. The long grain rice sample produced a rice bread with better crumb texture.
The applications of rheology to the main processes encountered during breadmaking (mixing, sheeting, fermentation and baking) are reviewed. The most commonly used rheological test methods and their relationships to product functionality are reviewed.It is shown that the most commonly used method for rheological testing of doughs, shear oscillation dynamic rheology, is generally used under deformation conditions inappropriate for breadmaking and shows little relationship with end-use performance. The frequency range used in conventional shear oscillation tests is limited to the plateau region, which is insensitive to changes in the HMW glutenin polymers thought to be responsible for variations in baking quality. The appropriate deformation conditions can be accessed either by long-time creep or relaxation measurements, or by large deformation extensional measurements at low strain rates and elevated temperatures.Molecular size and structure of the gluten polymers that make up the major structural components of wheat are related to their rheological properties via modern polymer rheology concepts. Interactions between polymer chain entanglements and branching are seen to be the key mechanisms determining the rheology of HMW polymers. Recent work confirms the observation that the dynamic shear plateau modulus is essentially independent of variations in MW of glutens amongst wheat varieties of varying baking performance and also that it is not the size of the soluble glutenin polymers, but the secondary structural and rheological properties of the insoluble polymer fraction that are mainly responsible for variations in baking performance. Extensional strain hardening has been shown to be a sensitive indicator of entanglements and long-chain branching in HMW polymers, and is well related to baking performance of bread doughs. The Considere failure criterion for instability in extension of polymers defines a region below which bubble walls become unstable, and predicts that when strain hardening falls below a value of around 1, bubble walls are no longer stable and coalesce rapidly, resulting in loss of gas retention and lower volume and texture. Strain hardening in doughs has been shown to reach this value at increasingly higher temperatures for better breadmaking varieties and is directly related to bubble stability and baking performance.
Coeliac patients suffer from an immune mediated disease, triggered by the ingestion of a protein composite (gluten) found in wheat, rye and barley. Consequently, there is a need for products such as bread or pasta, made from alternative cereal grains or pseudocereals. A fair proportion of the gluten free products currently on the market are nutritionally inadequate. Hence, it was the aim of this study to investigate the nutrient composition of seven commonly used commercial gluten free flours (oat, rice, sorghum, maize, teff, buckwheat and quinoa) and compare them to wheat and wholemeal wheat flour. In addition to the levels of all major compounds, also mineral composition, fatty acid profile, phytate, polyphenols and folate content were determined. Furthermore, properties of carbohydrates were studied in greater detail, looking at total and damaged starch levels; total, soluble and insoluble dietary fibre content as well as amylose/amylopectin ratio. Proteins were further investigated by means of capillary electrophoreses. Additionally, the ultra-structure of these materials was explored using scanning electron microscopy. The results show that maize and rice flour are poor regarding their nutritional value (low protein, fibre, folate contents). In contrast, teff as well as the pseudocereals quinoa and buckwheat show a favourable fatty acid composition and are high in protein and folate. In particular, quinoa and teff are characterised by high fibre content and are high in calcium, magnesium and iron. Therefore these flours represent nutrient-dense raw materials for the production of gluten free foods. (C) 2012 Elsevier Ltd. All rights reserved.
Creep-recovery measurements were used to analyze the non-linear viscoelastic properties of wheat flour. First the effect of creep time, recovery time and shear stress was investigated on the non-linear viscoelastic properties of Bussard dough. The Burgers model was fitted to the creep and recovery curves. A linear increase of maximum creep compliance was observed with increasing creep time. On the other hand, maximum recovery compliance remained constant but an increase of the retardation time was observed which indicates a slower recovery. A recovery time of 10 min seemed to be sufficient to obtain most of the recovery. Maximum creep compliance increased proportionally with increasing shear stress until a plateau was reached. Maximum recovery was constant between 100 and 500 Pa but the speed of the recovery increased as shear stress increased. Finally, the optimised creep-recovery methodology was used to analyze the non-linear viscoelastic properties of 17 pure wheat cultivars. By applying principal component analysis, it was possible to identify three groups of wheat cultivars with similar rheological properties and bread volumes.Highlights► Creep time and shear stress influence the Burgers model parameters of wheat dough. ► Retardation time is highly depends on creep time and shear stress. ► A sufficiently high shear stress is needed for grouping wheat flours. ► Grouping is based on deformability and recovery retardation time.
Stickiness of wheat dough using 51 international wheat genotypes was measured ten-times per sample using a texture analyzer and the improved Chen-Hoseney stickiness cell. Repeated measures analyses were carried out with the parameters adhesive force, adhesiveness, and stringiness of the force-time curves using the SAS MIXED procedure. The data revealed a high variability among observations from replicates of the same sample preparation. It is suggested to analyze a large (seven to ten) number of repeated measures per sample to account for the variation. Triplicate measures that result in reliable means with low standard errors for the particular lab conditions and test settings can be found by a repeated measure analysis.
The study of new gluten-free foods suitable for celiac people is necessary since people allergic to wheat proteins are more and more frequent. This study examined the effect of using different starch sources (rice, corn, potato and wheat) and protein types (soy protein isolate, wheat protein) at different percentages (0%, 10%, 20%), on the rheological properties of batters (flow, viscoelastic and stickiness behaviour) and on batter density and cake volume. The highest consistency, viscous and elastic moduli, and adhesive force corresponded to batters made of rice starch and soy protein isolate, which showed the most similar rheological behaviour to wheat flour batters. The batters obtained showed adequate characteristics in processing and in achieving high quality products. However, the percentages of starches and proteins should be experimentally optimized in each case.
In this study, the application of glucose oxidase and protease commercial preparations was investigated in order to evaluate
their impact on the breadmaking performance of four different gluten-free flours (buckwheat, corn, sorghum and teff). Bread
formulas were developed without addition of hydrocolloids in order to avoid synergistic effects. Glucose oxidase improved
corn (CR) and sorghum (SG) bread quality by increasing specific volume (P<0.05) and reducing collapsing at the top. The improvements could be related to protein polymerization which resulted in
enhanced continuity of the protein phase and elastic-like behavior of CR and SG batters. No significant effects were detected
on buckwheat (BW) and teff breads. On the other hand, protease treatment had detrimental effects on the textural quality of
BW and SG breads. The effects were related to protein degradation resulting in increased liquid-like behaviour of BW and SG
batters. Overall, the results of this study suggest that protein polymerisation can improve the breadmaking performance of
gluten-free flours by enhancing elastic-like behaviour of batters. However, the protein source is a key element determining
the impact of the enzymes. In the absence of hydrocolloids, protein structures are important to ensure the textural quality
of these types of breads.
Contenido: Monosacáridos; Reacciones de los carbohidratos; Oligosacáridos; Polisacáridos; Comportamiento de soluciones, dispersiones y geles de polisacáridos; Almidón; Celulosas; Hemicelulosas; Guar y goma de algarrobilla; Xanano; Carrageninas; Alginato; Pectinas; Gomas segregadas; Agentes abultantes, grasas artificiales y nutrición de carbohidratos; Endulzantes.
To the Editor: Celiac disease is caused by aberrant T-cell responses to wheat gluten and the gluten-like proteins in barley and rye.1 The only cure for the disease is a lifelong gluten-free diet. Although consumption of oats is generally considered safe for patients with celiac disease,2 recent studies indicate that the grain does contain T-cell–stimulatory epitopes1,3 and that symptoms of celiac disease develop in some patients after the consumption of oats.4 A cereal lacking T-cell–stimulatory peptides would thus be of great value to patients with celiac disease. Tef (Eragrostis tef) is a cereal traditionally grown in Ethiopia . . .
Food-based strategies to enhance iron and zinc bioavailability of complementary foods consumed by young children in Ethiopia
- K Baye
Baye K (2013) Food-based strategies to enhance iron and
zinc bioavailability of complementary foods consumed by
young children in Ethiopia. Ph.D. dissertation, University of
Montpellier
Physico-chemical characterization of grain tef
- G Bultosa
- A N Hall
- Jrn Taylor
Bultosa G, Hall AN, Taylor JRN (2002) Physico-chemical characterization of grain tef [Eragrostis tef (Zucc.) Trotter] starch.
Starch/Stärke 54:461-468
The use of rheological techniques to elucidate durum wheat dough stretch properties
- N M Edwards
- J E Dexter
- M G Scanlon
- NM Edwards
Edwards NM, Dexter JE, Scanlon MG (2001) The use of rheological techniques to elucidate durum wheat dough stretch
properties. Fifth Ital Conf Chem Process Eng Florence Ital
2:825-830
Preventing chronic diseases: a vital investment
World Health Organization (WHO) (2005) Preventing chronic
diseases: a vital investment. WHO, Geneva