Дисертації з теми "Bread dough"
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1
Ng, Shen Kuan (Trevor Shen Kuan). "Extensional rheology of bread dough." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38267.
Анотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (p. 99-107).
We investigated the extensional properties of wheat flour dough on the Filament Stretching Rheometer (FISER), in which the sample approaches uniform uni-axial extension flow at a constant strain rate over a large portion of the experiment, thereby allowing us to directly probe the transient material function characterizing the behavior of dough in extension. The large dynamic range of this Rheometer permitted us to investigate the visco-elastic nature of the dough well into the baking/proofing range. Special experimental protocols and modifications to the rheometer fixtures were designed and built to overcome problems in sample preparation. Parameters such as water content, base flour type and mixing conditions were varied to determine their respective effects on the extensional properties. Ultimately we would like to develop a constitutive equation describing the evolution of stress during extension and arrive at a model for the stability against rupture in these doughs.
(cont.) This will form the basis for developing protocols to map results from the true uni-axial extension experiments onto empirical measurements obtained from existing and widely utilized industrial standard testing devices. As an example in this first stage, we focused on the Mixograph, which is a widely accepted method of testing dough in the food industry, and considered how its output can be related to the true material functions generated in filament stretching rheometry.
by Shen Kuan Ng.
S.M.
2
Trinh, Linda. "Gas cells in bread dough." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/gas-cells-in-bread-dough(617b6c1d-273a-4223-a3f3-090d75ed7d0e).html.
Анотація:
Gas cells make up a significant proportion of bread’s volume and are responsible for a number of bread’s characteristics, making their size distribution throughout bread an important quality parameter. The number and size of cells affect the texture and volume of bread, the quantity of sauce mopped up, and how bright the bread appears. Gas cells are incorporated into bread dough during mixing and manipulated throughout the breadmaking process to obtain the desired cellular structure. Due to the fragile nature of bread dough, obtaining accurate quantitative data on its cellular structure is challenging. This thesis investigates the cellular structure of bread, as well as assessing the effect of sugar during breadmaking. Magnetic resonance imaging (MRI), microscopy and X-ray computerised tomography (X-ray CT) have been used throughout research in bread dough to visualise dough’s cellular structure. A non-destructive and non-invasive method giving a high resolution is X-ray CT, in particular when using a synchrotron light source. However, time on a synchrotron beamline is highly competitive, and can require applications more than two years in advance. Running costs of experiments from a synchrotron beamline are also high. This thesis details an alternative X-ray set-up to accurately visualise dough’s cellular structure using a conventional and therefore more easily accessible X-ray source. Three X-ray CT experiments were conducted to investigate dough’s cellular structure throughout mixing, during proving and in different sugar content doughs. The resolution of the scans varied from 7-11 µm. Industrial bread dough mixing is often conducted at a high pressure initially to improve oxygen availability, followed by a period of partial vacuum to favourably manipulate the cell size distribution. Using X-ray CT, dough cell size distribution was measured at different points throughout pressure-vacuum and constant pressure mixing. A simplified population balance model was fitted to the measured cell size distributions and the validity of the assumptions within the simplified model explored. It was shown that the dynamic changes in the cell size distribution within bread dough could be accurately measured during pressure step change mixing with a non-synchrotron X-ray source. Pressure-vacuum mixing was shown to give a finer cell distribution than constant pressure mixing and the observed decrease in cell number density was found to be much more short lived than the decrease in cell size. The model was found to provide a reasonably accurate characterisation of pressure-vacuum mixing. X-ray CT was also used to monitor dough’s changing cellular structure during proving by taking scans every 5 minutes over 145 minutes. Dough voidage increased from 3% to 66%, resulting in a volume increase from 544 mm3 to 1293 mm3. Cell growth was quickest between 40 and 140 minutes, where a steady increase in volume and significant changes in the cell structure occurred. A change in voidage distribution was observed, with greater proportions of gas located in larger cells over time. In addition, over the course of proving cell numbers dropped, a 156-fold increase in mean cell volume occurred, and mean cell Feret shape increased from 1.59 to 1.91. This in-situ method of X-ray imaging of bread dough provides higher resolution images than comparable data from conventional X-ray sources. In addition, the method has proved to be effective in obtaining high resolution and high contrast 3D images of the cellular structure of dough. This technique will help those wanting to investigate cellular changes in the dough dynamically, but without the waiting time and applications that are required with synchrotron X-rays. On investigating the effect of sugar during breadmaking, sugar was found to increase the gas free dough density and dough voidage, change the dough’s rheology, increase its proving time and produce denser bread. Application of a population balance model on the experimental results indicate that the decrease in steady state voidage as the sugar content increases is a result of an increase in disentrainment. This was reflected in the X-ray CT of sugared vs. non-sugared doughs through fewer and smaller cells present in sugared doughs. This is likely to be a result of a weaker dough structure, making cell rupture more likely. The Chorleywood Bread Process (CBP) is used industrially worldwide for the production of bread in less time and using inferior ingredients compared to the traditional bulk fermentation process, making it more cost effective. These results show that simply extending the pressure vacuum mixing used for the production of standard bread loaves in the CBP to sugared doughs should be avoided as aeration of sugared doughs differs to non-sugared doughs. The results suggest that to do so would be detrimental to the product quality.
3
Campbell, Grant M. "The aeration of bread dough during mixing." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302951.
4
Sevenou, Olivier. "Starch : its relevance to dough expansion during baking." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250474.
5
Lin, Hsing-I. "Using enzymes to improve frozen-dough bread quality." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/554.
6
Hamlet, Colin G. "Monochloropropanediols in bread : model dough systems and kinetic modelling." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408579.
7
Robinson, Simone. "Fungal xylanases : purification, characterisation and bread improving properties." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299307.
8
Ng, Shen Kuan (Trevor Shen Kuan). "Linear to nonlinear rheology of bread dough and its constituents." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42288.
Анотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 263-282).
There are many practical reasons for studying the deformational behavior or rheological properties of a dough system. The mass production of bread has led to a need of machines that are able to handle and process large volumes of dough. An understanding of the deformational properties can aid in designing machines of this kind. Less obviously, the texture of the bread we eat is governed by the mechanical properties of the dough from which it is proofed and baked from. During the bread making process, large non-linear deformations feature prominently. In mixing and kneading, dough is stretched and sheared by hand or by specially designed mixing devices, while in proofing and baking, the expansion of gas cells causes significant extensional strain on the surrounding dough. Other than directly affecting the moduli of the fibers and membranes in the solid phase of bread, a link between the rheology of dough and the baked loaf volume has also been established. In this thesis, we first develop consistent and accurate techniques for measuring the rheological properties of the dough. Good experimental techniques and protocols are essential for studying the mechanical properties of such a sticky, visco-elasto-plastic, time-dependent material. We modify some of the standard rheometric hardware and protocols to accommodate this unusual material. Special attention is given to nonlinear deformations such as uniaxial extensional flows and large amplitude oscillatory shear flows (LAOS). We use the new techniques to probe the microstructure of dough and its constituents from a mechanical viewpoint. The strongly nonlinear rheological properties of dough arise from the interactions of a protein matrix and a high filler concentration consisting of hydrated starch particles.
(cont.) We demonstrate that the gluten protein that imbues the dough with its characteristic viscoelasticity should be considered as a transient network that is interconnected by finitely extensible biopolymer segments (-20nm mesh size) and held together by hydrogen bonds and/or hydrophilic interactions. Using this renewed understanding of the microstructure, we construct appropriately frame-invariant constitutive equations (generalized gel equation and a multi-mode FENE network model) that describe the rheology of gluten gels with a minimal number of parameters. The behavior of gluten gels can then be related to prototypical flour-water doughs by the effects of the starch filler using the concept of strain amplification. Finally, this general framework of microstructure and rheological properties of gluten gels and flour-water dough are applied to practical situations. We discuss the utility of this work in context to some specific case studies of rheological aging, the effects of water content and flour-type variations.
by Trevor Shen Kuan Ng.
Ph.D.
9
Armaghani, F. A. S. "A study of two sour dough starter cultures." Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382372.
10
Nitcheu, Ngemakwe Patrick Hermaan. "Effect of transglutaminase and cyclodextrinase on the rheological and shelf-life characteristics of oat bread." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/832.
Анотація:
Thesis presented in partial fulfilment of the requirements for the degree of
Master of Technology (Food Technology)
Department of Food Technology
Faculty of Applied Sciences
2014The aim of this study was to evaluate the effect of transglutaminase (TG) and cyclodextrinase (CG) on the rheological characteristics of oat dough and shelf-life characteristics of oat bread with a view to developing oat bread with improved texture and shelf-life. Firstly, the effects of yeast, carboxylmethylcellulose (CMC), plain yoghurt (YG), transglutaminase (TG) and cyclodextrinase (CG) on the mixing, pasting, thermal, quantification of free amino acid groups and protein crosslinking properties of oat dough were investigated through a 25-2 fractional factorial design resolution III with yeast (1.25, 3.25%), CMC (1, 2%), YG (10.75, 33.75%), TG (0.5, 1.5%) and CG (10, 40 μl) as independent variables. Among all the ingredients, only CMC, YG, and TG exhibited significant (p < 0.05) effects on the mixing properties of oat dough while yeast and CG slightly affected it. TG addition increased water absorption (34.80 - 38.45%) and peak resistance (696.40 - 840.30 FU) but decreased the dough softening (93.20 - 67.75 FU) as its level varied from 0.5 to 1.5 g. CG did not significantly (p > 0.05) affect the mixing properties of oat dough. As its level increased from 10 - 40 μl, the water absorption (38.45 - 34.80%), energy at peak (11.45 - 3.75 Wh/kg), peak resistance (840.30 - 696.40 FU) slightly decreased while the softening of oat dough increased from 67.75 to 93.20 FU. The addition of yeast and YG showed significant (p < 0.05) impacts on the pasting properties of oat dough compared to CMC, TG and CG. The storage modulus of oat dough was slightly (p > 0.05) increased by adding TG (180.37 - 202.78 kPa) and CG (170.75 - 175.71 kPa). TG decreased the loss modulus (65.95 - 62.87 kPa) of oat dough while CG increased it from 62.01 - 64.61 kPa. The thermal properties of oat dough were slightly affected by all the ingredients. The denaturation temperature was increased by incorporation of TG (6.53 - 8.33°C) and CG (6.42 - 8.33°C) but there was a decrease of enthalpy due to addition of TG (from 0.76 to –4.05 J/g) and CG (1.11 to –4.05 J/g). Only CG decreased the number of free amino acid groups (0.94 - 0.62) confirming that it catalysed the protein crosslinking of the oat glutelin while other ingredients increased it. Secondly, as CMC, YG and TG affected the mixing, pasting and thermal properties of oat dough, oat bread was baked with carboxylmethylcellulose (CMC), yoghurt (YG) and transglutaminase (TG) following a 33 Box-Behnken design consisting of CMC (1, 2 g), YG (10.75, 33.75 g) and TG (0.5, 1.5 g) as independent variables. The physical and textural analysis of oat bread showed that CMC, YG and TG addition did affect oat bread. TG decreased the springiness (6.47 - 4.14 mm), specific volume (1.61 - 1.54 ml/g) and increased hardness (537.85 - 692.41 N) of oat bread. No significant effect was observed on the colour parameters of crust and crumb of oat bread. Despite the optimal oat bread exhibited a high desirability, its high hardness and low springiness remain some challenges associated with oat bread production. Since it was well established that TG increased hardness and decreased springiness of the optimal oat bread, improvement was needed for the production of best oat bread. Thirdly, Psyllium husks (PH) and cyclodextrinase (CG) were added in five (05) best oat bread formulations such as (1) PH + CG, (2) CG, (3) TG + CG, (4) TG + PH and (5) TG + PH + CG. The best oat bread formulation with low hardness containing PH and CG was further used for sensory and shelf-life studies. The combination of ingredients psyllium husks and cyclodextrinase significantly (p < 0.05) improved the textural properties of best oat bread. It decreased the hardness (94.88 N) and increased the springiness (10.97 mm) of the best oat bread. Fourthly, the sensory evaluation showed that the consumers highly appreciated the crumb colour and texture of the best oat bread than the ones of wheat bread. In addition, they found that there was a strong correlation in crust and crumb colour between wheat and the best oat bread. However, some differences existed between the wheat and best oat bread. The best oat bread exhibited a less preference in taste than its wheat counterpart. The best oat bread positively received an overall acceptability (4.07) as wheat bread (4.22). Fively, the shelf-life studies of the best oat bread revealed that the pH and TVC of the best oat bread were more affected by the time, temperature and the interaction of both parameters (time and temperature) than Total Titratable Acidity (TTA), yeasts and mould as the storage time passed. The best oat bread could safely be stored up to 21 days at refrigeration temperature (5°C) with a Total Viable Count (TVC) load of 105 cfu/g. Finally, using survival analysis for the shelf-life studies of the best oat bread, the mathematical model revealed that the risk of deteriorating increased with the temperature.
11
Van, der Graaf John E. "Isolation, purification and characterisation of a novel Mâ†r 50k wheat protein." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343324.
12
Zambelli, Rafael Audino. "Development of a methodology to glaze frozen dough for bread production." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14965.
Анотація:
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel SuperiorA tÃcnica de glazeamento à utilizada em produtos de confeitaria e pÃes doces, com a finalidade de promover a melhoria das caracterÃsticas externas do produto. O estudo teve como objetivo desenvolver soluÃÃes de glazeamento compostas de matÃrias-primas nÃo-convencionais como Ãleos vegetais, vegetais em pà e subprodutos do processamento de frutas e avaliar o processo de obtenÃÃo dos pÃes tipo forma atravÃs da tecnologia de massas congeladas verificando o efeito da estocagem por 60 dias nos parÃmetros de qualidade dos pÃes. As soluÃÃes de glazeamento contendo Ãleos vegetais foram: Ãleo de algodÃo/Ãgua, Ãleo de canola/Ãgua, Ãleo de girassol/Ãgua; Ãleo de milho/Ãgua e Ãleo de soja/Ãgua. As soluÃÃes de glazeamento contendo vegetais em pà foram: brÃcolis em pÃ/Ãgua; espinafre em pÃ/Ãgua; palmito em pÃ/Ãgua e tomate em pÃ/Ãgua. As soluÃÃes de glazeamento contendo subprodutos (cascas) de processamento de frutas foram: subproduto de abacaxi/polpa de abacaxi; subproduto de caju/polpa de caju; subproduto de goiaba/polpa de goiaba e subproduto de manga/polpa de manga. Cada uma destas soluÃÃes foi desenvolvida atravÃs de um Delineamento Composto Central Rotacional (DCCR) totalizando 11 ensaios, com trÃs repetiÃÃes no ponto central. A metodologia estatÃstica aplicada consistiu em anÃlise descritiva dos dados, testes de normalidade, anÃlise de variÃncia (ANOVA) e nÃo-paramÃtrica, teste de mÃdia Tukey, anÃlise de regressÃo mÃltipla, anÃlise de correlaÃÃo e superfÃcies de resposta. Os efeitos do perÃodo de estocagem congelada (0, 15, 30, 45 e 60 dias) foram avaliados sobre os parÃmetros fÃsicos de qualidade das massas. Para as soluÃÃes contendo Ãleos vegetais e Ãgua verificou-se que o maior volume obtido foi pela soluÃÃo de Ãleo de algodÃo e Ãgua com 4,23 mL/g, seguido da soluÃÃo com Ãleo de milho/Ãgua (4,03 mL/g). Atribuiu-se a menor viscosidade destes Ãleos a nÃo-formaÃÃo de pelÃcula externa à massa, nÃo prejudicando as transferÃncias de calor e massa durante a fermentaÃÃo e forneamento. O Ãndice de expansÃo foi superior a 2,00 para todas as soluÃÃes com exceÃÃo das compostas por Ãleo de canola/Ãgua e Ãleo de girassol/Ãgua. Com relaÃÃo Ãs soluÃÃes contendo vegetais em pà e Ãgua, observou-se que os volumes especÃficos, de modo geral, foram superiores aos obtidos pelas soluÃÃes adicionadas de Ãleo. Os vegetais em pà podem fornecer micronutrientes para as leveduras e melhorar o processo fermentativo, resultado devido ao maior nÃmero de alvÃolos apresentado, tendo obtido valores acima de 1.000 alvÃolos para todos os vegetais, exceto o palmito, portanto, apresentaram miolos com boa porosidade. Verificou-se que as soluÃÃes de glazeamento contendo subprodutos e polpa de frutas promoveram os menores volumes especÃficos para os pÃes, onde nenhum ensaio apresentou valores maiores que 4,00 mL/g. Este resultado pode estar relacionado com o pH Ãcido das frutas e a presenÃa de enzimas proteolÃticas que podem danificar a estrutura do glÃten, reduzindo a capacidade de retenÃÃo gasosa ou prejudicar a atividade das leveduras. AtravÃs das superfÃcies de resposta e modelos matemÃticos gerados foi possÃvel selecionar duas soluÃÃes de glazeamento para cada tratamento, totalizando 26 soluÃÃes que foram utilizadas em massas congeladas por atà 60 dias, onde foi avaliado o seu potencial para a manutenÃÃo da qualidade. Verificou-se que a estocagem congelada das massas reduziu o volume especÃfico, Ãndice e fator de expansÃo, pH, umidade total e volume produzido. Entretanto, as soluÃÃes de glazeamento, de modo geral, promoveram a reduÃÃo no descrÃscimo da qualidade ao longo do tempo de estocagem, quando comparados Ãs massas controle, ausentes da aplicaÃÃo das soluÃÃes de glazeamento. A aplicaÃÃo de soluÃÃes de glazeamento em massas congeladas para a produÃÃo de pÃes tipo forma, portanto, consiste em uma tecnologia que pode ser utilizada em processos industriais pois demonstrou eficÃcia na manutenÃÃo da qualidade das massas apÃs 60 dias de estocagem congelada, alÃm poder contribuir para a melhoria da qualidade nutricional dos produtos.
The glazing technique is used in bakery products and confectionery, in order to promote the improvement of the external characteristics of the product. The objective of this study was to develop composite glazing solutions of unconventional raw materials like vegetable oils, powdered vegetables and by-products of fruit processing through statistical tool Central Composite Rotational Design (CCRD) and study the process of getting the bread through the frozen dough technology evaluating the effect of storage for 60 days in the quality of breads parameters. The glaze solutions containing vegetable oils are: cottonseed oil/water, canola oil/water, sunflower oil/water; corn oil/water and soy oil/water. The glaze solutions containing powdered vegetables were broccoli powder/water; Spinach powder/water; palmito powder/water and tomato powder/water. The glazing solutions containing fruit processing by-products were byproduct of pineapple/pineapple pulp; byproduct of cashew/pulp cashew; Guava byproduct/guava pulp and byproduct mango/mango pulp. Each of these solutions was developed through a CCRD total of 11 samples with three replications at the center point. The applied statistical methodology consisted of descriptive data analysis, normality tests, analysis of variance (ANOVA) and nonparametric, average Tukey test, multiple regression analysis, correlation analysis and response surfaces, we used these tests to check the effect of different glazing solutions on the quality of physical parameters - specific volume, density, expansion factor of the dough, expansion index of breads, volume produced during fermentation, number and circularity of alveoli - to establish the conditions great to hold each of the study with frozen dough. The effects of frozen storage time (0, 15, 30, 45 and 60 days) were evaluated by the aforementioned parameters, and the total water content of the dough, acidity and pH. For solutions containing vegetable oils and water has been found that the greater volume was obtained by cotton seed oil and water solution with 4.23 mL/ g, followed by the solution of corn oil/water (4.03 mL/g) This result is related to the lower viscosity of these oils, attributing to non-formation of outer film to the dough and does not impair the heat and mass transfer during fermentation and baking. The expansion ratio was greater than 2.00 for all solutions except those consisting of canola oil/water and sunflower oil/water. With respect to solutions containing vegetable powder and water, it was observed that the specific volumes generally were higher than those obtained by the added oil solutions. In this case, the vegetable powder can provide micronutrients for the yeast and improve the fermentation process, results related to the higher number of wells shown (above 1000 for all vegetables except palmito) therefore presents brains with good porosity. It was found that the glazing solutions containing by-products and fruit pulp promoted, generally smaller specific volumes for the loaves, where no test showed values above 4.00 mL/g, this result may be related to the pH acid fruits and the presence of proteolytic enzymes that can damage the gluten structure and, consequently, reduce the gas retaining capacity, or impair the activity of the yeast. Therefore, before the results, we selected two glazing solutions for each treatment, totaling 26 glazing solutions to be used in frozen dough for up to 60 days and evaluate its potential as a quality preserving agent. Through the response surface and mathematical models generated it was possible to select two glazing solutions for each treatment, totaling 26 solutions that were used in frozen dough for up to 60 days, which was evaluated its potential as a quality preserving agent. It was found that frozen storage of the dough reduced the specific volume, expansion index, expansion factor pH, moisture and volume produced. However, the glazing solutions generally have promoted the reduction in the quality descrÃscimo over storage time, when compared to mass control, absent the application of glazing solutions. Application of glazing solutions frozen dough for producing bread-like form thus consists of a technology that can be used in industrial processes as it has demonstrated its effectiveness in maintaining the quality of the pasta after 60 days of frozen storage, in addition to contribute to improving the nutritional quality of products.
13
Schlepp, Emily Beth. "Effect of Flaxseed Fiber on Bread Quality Obtained from Frozen Dough." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26712.
Анотація:
Fiber in frozen bread dough is thought to reduce the loss of yeast vitality and improve nutrition and quality of bread. The objective of this study was to determine the applicability of flaxseed fiber in frozen bread dough. Fiber was extracted from two sources of brown flaxseed and added to bread formulas at 0%, 1% and 3%. Dough was blast chilled and kept frozen until thawed at scheduled intervals. Thawed dough was proofed, baked into bread. Bread was tested analytically and by a sensory panel. Loss of overall quality was observed overtime. Breads containing flaxseed fiber had significantly larger loaf volumes (cc) and reduced firmness (g). A trained sensory panel detected significantly lower crumb firmness and stale flavors in breads containing flaxseed fiber. These results suggest flaxseed fiber has the potential to improve the perceived quality of frozen bread dough.
14
Gajula, Hyma. "Effect of wheat bran on gluten network formation as studied through dough development, dough rheology and bread microstructure." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35570.
Анотація:
Doctor of PhilosophyDepartment of Grain Science and Industry
Hulya Dogan
Jon M. Faubion
The overall hypothesis underlying this study is that the nature and extent of bran interactions with the gluten protein matrix play a dominant role in both 'in-process' dough and final product quality of whole grain baked goods. Therefore, the purposeful manipulation of those interactions should be able to minimize adverse processing or product characteristics resulting from bran inclusion/presence. The approach we took was to study the effects of bran milled to different particle sizes on dough development during and after dough mixing using fundamental rheology combined with traditional cereal chemistry approaches and x-ray microtomography (XMT). The research outcomes were used to create a better picture of how the bran is effecting the dough development and to suggest strategies that allow for the control of that effect. Study-I focused on characterization of the chemical properties, empirical rheological properties and baking performance of flours and dough with different bran contents from different sources. The development of dough microstructure and the resulting crumb texture in the presence of different bran were studied using XMT. HRW and SW bran additions resulted in higher water absorptions (WA) irrespective of the flour type and bran source. Fine bran caused slightly higher WA followed by coarse and as is bran. Both HRW and SW bran decreased the dough stability of HRW flour, while it improved the stability of SW flour doughs. Macro and microstructure of baked products were significantly affected both bran type and addition level. HRW bran added to HRW flour resulted in 8-23% decrease in loaf volume while SW bran added at the same level caused 3-11% decrease. XMT indicated that bran decreased the total number of air cells significantly. SW flour resulted in harder crumb texture than that of HRW flour breads. Overall, SW bran had less detrimental effects on mixing and baking performance of HRW flour. Study-II focused on specific bran particle size and composition on small and large deformation behavior of strong and weak flour doughs. Small deformation behavior was characterized using frequency and temperature sweep tests, while the large deformation behavior was studied using creep–recovery and uniaxial extensional testing. The results revealed that the rheological behavior of bran-enriched doughs depend on type of base flour, bran type, bran replacement level (0, 5, 10%), and the dough development protocol. Weak flour doughs benefited from inclusion of bran as inherently low peak height and stability of these doughs improved in the presence of bran. Temperature sweeps indicated a slight decrease in Gʹ and G" until around 55-60°C. In the same temperature range, presence of bran increased the moduli of composite four compared to that of the control flours. Creep compliance parameters indicated that both bran source and bran replacement had significant effect on maximum compliance (J[subscript max]) and elastic compliance (J[subscript e]). Finally, the bran type affected uniaxial extensional properties, maximum resistance (R[subscript max]) and elasticity (E), significantly independent from the type of base flour.
15
Ziegler-Purcell, Ulrike G. "Rheological mechanisms governing variation in the extent of gas cell expansion in bread dough." Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250682.
16
Oshikiri, Reona. "Fundamental bases for the improving action of novel enzyme-oxidant combinations in frozen dough." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/15518.
Анотація:
Master of ScienceDepartment of Grain Science and Industry
J.M. Faubion
The market for frozen goods is expanding and the frozen dough goods sector still has potential to expand its market. It is well known that deterioration in bread quality occurs during frozen dough/bread production. In addition, it is known that dough rheology influences bread quality. To prevent deterioration of bread quality, many additives have been used and researched. Combinations of oxidants (potassium bromate and ascorbic acid) are widely used worldwide. However, potassium bromate may be carcinogenic to humans, and it has been detected in bread after baking. Since it has been prohibited or strictly limited in many countries, many researchers have tried to find a replacement. Ascorbic acid is safe for human intake, and does not persist in bread. However, it is not as effective as potassium bromate. Possible replacements in frozen doughs include oxidant (ascorbic acid)-enzyme combinations. This study evaluated the effects of ascorbic acid-specific enzyme combinations as a replacement for the potassium bromate in frozen dough and related the effects to dough behavior (gluten network strength) as evaluated by dynamic oscillation rheometry. Bread quality was evaluated by test baking. Based on the results from fresh baking studies, potassium bromate can be replaced by an optimum level combination of ascorbic acid and hemicellulase/endo-xylanase. This combination clearly improved loaf volume, and crumb grain over both control and potassium bromate containing doughs. For frozen dough/bread production, the addition of all additives improved bread quality, but ascorbic acid and endo-xylanase containing dough resulted in higher volume, and better crumb structure than did dough containing potassium bromate. Dough rheology experiments show that rheology was affected by both the process and additives. Strain sweeps gave the information about dough stability. Both the additives and proofing improved dough stability. Dough behavior (gluten network strength) was assessed by frequency sweeps. Dough containing ascorbic acid and endoxylanase was most stable during frozen dough processing.
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Rahman, Md Mahfuzur. "An Initiative to Clean Label: Can We Replace Dough Strengtheners in Bread Formulations." Thesis, North Dakota State University, 2018. https://hdl.handle.net/10365/28734.
Анотація:
Dough strengtheners are the most common and largest group of chemicals used in bread formulations. This study evaluated the capability of hard red spring (HRS) wheat flour to replace commercial dough strengtheners in bread production. Doughs were prepared by blending different percentages (10%, 20%, 30% and 40%) of four different HRS wheat flours with hard red winter (HRW) wheat flour. In addition, doughs were prepared by adding ten commercially available additives with HRW wheat flour to compare the dough strengthening ability of HRS wheat flour. All the HRS wheat flour blends had significantly (p<0.05) strong dough rheological characteristics than most of the additives. The 40% blends of HRS wheat cultivar Glenn and Linkert had better bread making quality than other blends and all the additives. The SE-HPLC unextractable protein fractions of these two cultivars also showed a better correlation with bread making properties than all the additives.
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Chlapowski, Yolantha Sophie. "Effect of dough conditioners on the bread-making qualities of soft wheat flour." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43964.
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Khatkar, Bhupendar Singh. "Functional and dynamic rheological properties of wheat gluten." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319243.
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Balestra, Federica <1979>. "Empirical and fundamental mechanical tests in the evaluation of dough and bread rheological properties." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1941/.
Анотація:
Bread dough and particularly wheat dough, due to its viscoelastic behaviour, is probably the most dynamic and complicated rheological system and its characteristics are very important since they highly affect final products’ textural and sensorial properties. The study of dough rheology has been a very challenging task for many researchers since it can provide numerous information about dough formulation, structure and processing. This explains why dough rheology has been a matter of investigation for several decades.
In this research rheological assessment of doughs and breads was performed by using empirical and fundamental methods at both small and large deformation, in order to characterize different types of doughs and final products such as bread. In order to study the structural aspects of food products, image analysis techniques was used for the integration of the information coming from empirical and fundamental rheological measurements.
Evaluation of dough properties was carried out by texture profile analysis (TPA), dough stickiness (Chen and Hoseney cell) and uniaxial extensibility determination (Kieffer test) by using a Texture Analyser; small deformation rheological measurements, were performed on a controlled stress–strain rheometer; moreover the structure of different doughs was observed by using the image analysis; while bread characteristics were studied by using texture profile analysis (TPA) and image analysis.
The objective of this research was to understand if the different rheological measurements were able to characterize and differentiate the different samples analysed. This in order to investigate the effect of different formulation and processing conditions on dough and final product from a structural point of view.
For this aim the following different materials were performed and analysed:
- frozen dough realized without yeast;
- frozen dough and bread made with frozen dough;
- doughs obtained by using different fermentation method;
- doughs made by Kamut® flour;
- dough and bread realized with the addition of ginger powder;
- final products coming from different bakeries.
The influence of sub-zero storage time on non-fermented and fermented dough viscoelastic performance and on final product (bread) was evaluated by using small deformation and large deformation methods. In general, the longer the sub-zero storage time the lower the positive viscoelastic attributes.
The effect of fermentation time and of different type of fermentation (straight-dough method; sponge-and-dough procedure and poolish method) on rheological properties of doughs were investigated using empirical and fundamental analysis and image analysis was used to integrate this information throughout the evaluation of the dough’s structure. The results of fundamental rheological test showed that the incorporation of sourdough (poolish method) provoked changes that were different from those seen in the others type of fermentation.
The affirmative action of some ingredients (extra-virgin olive oil and a liposomic lecithin emulsifier) to improve rheological characteristics of Kamut® dough has been confirmed also when subjected to low temperatures (24 hours and 48 hours at 4°C).
Small deformation oscillatory measurements and large deformation mechanical tests performed provided useful information on the rheological properties of samples realized by using different amounts of ginger powder, showing that the sample with the highest amount of ginger powder (6%) had worse rheological characteristics compared to the other samples.
Moisture content, specific volume, texture and crumb grain characteristics are the major quality attributes of bread products. The different sample analyzed, “Coppia Ferrarese”, “Pane Comune Romagnolo” and “Filone Terra di San Marino”, showed a decrease of crumb moisture and an increase in hardness over the storage time. Parameters such as cohesiveness and springiness, evaluated by TPA that are indicator of quality of fresh bread, decreased during the storage. By using empirical rheological tests we found several differences among the samples, due to the different ingredients used in formulation and the different process adopted to prepare the sample, but since these products are handmade, the differences could be account as a surplus value.
In conclusion small deformation (in fundamental units) and large deformation methods showed a significant role in monitoring the influence of different ingredients used in formulation, different processing and storage conditions on dough viscoelastic performance and on final product.
Finally the knowledge of formulation, processing and storage conditions together with the evaluation of structural and rheological characteristics is fundamental for the study of complex matrices like bakery products, where numerous variable can influence their final quality (e.g. raw material, bread-making procedure, time and temperature of the fermentation and baking).
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Padilla, Cesar, Aida Vivanco, Leonardo Vinces, and Mirko Klusmann. "Design of a multi-hole cylindrical extruder, driven by a linear actuator and used for the formation of bakery dough." Institute of Electrical and Electronics Engineers Inc, 2020. http://hdl.handle.net/10757/656628.
Анотація:
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.The present work proposes a solution for the conditioning of bakery dough with the purpose of reducing costs by replacing manual work with a mechanized system that will be a piston extruder. In the process, the mass will be contained within a 304 stainless steel prismatic matrix with multiple outlet openings for optimization of the production line. The mechanical properties of bread dough were studied for the design of the platform and the estimation of the necessary compression force. A linear actuator was used, which exerts a compression force of 6 kN, which maximum linear speed is 5 mm/s. Validation of results will be carried out through simulated tests with a density mass of 1452.9 kg/m3. The system is composed of a linear actuator that performs the function of an extruder, followed by a pneumatic wire cutter. The process continues with a conveyor belt and ends with the injection of sesame seeds.The fundamental contribution is in the design of the extrusion chamber, since it allows the flow of the mass leaving minimal residue.
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Sly, Alexandra Claire. "Improvement of zein dough characteristics using dilute organic acids." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/40337.
Анотація:
The only treatment for coeliac disease, a common autoimmune disorder, is life-long adherence to a gluten-free diet. However, the replacement of wheat gluten, a key structural and functional component in bread, poses a major technological challenge for food scientists. The use of non-wheat cereal proteins, as alternatives to gluten, shows much promise in gluten-free bread making. Literature has shown that when zein, the maize prolamin protein, is subjected to wet heat above its glass transition temperature (Tg), the protein becomes viscoelastic, rubbery and dough-like. Gluten-like fibrils are visible, which form complex protein networks similar to those found in wheat dough. The resulting zein dough has viscoelastic characteristics and can be successfully used with hydrocolloids to produce gluten-free bread.
This project examined the influence of wet heat treatment and dilute organic acids (lactic acid and acetic acid) on the dough-making quality of non-wheat cereal proteins, such as kafirin and zein. Zein was the only non-wheat cereal protein to show any physical change when it was subjected to wet heat treatments, forming a dough-like substance. Acidification of the zein dough prepared at 40°C with concentrations of 0.7, 1.3 and 5.4% (v/v) organic acid in distilled water solutions, showed that the higher the concentration of acid used, the greater its effect on the dough's rheological properties. Tensile tests using a Keifer rig on zein dough showed that as the concentration of organic acid was increased from 0.7 to 1.3 and to 5.4% (v/v) the dough become softer and increasingly more extensible. The dough also exhibited less resistance to extension and reduced elasticity. CLSM revealed that the zein doughs contained a protein network, made up of fine protein fibrils, which became smoother and more homogenous as the concentration of acid was increased. Although SDS-PAGE revealed that no oligomerization took place with acid addition,
iv
FTIR showed that zein dough prepared with distilled water at 40°C had elevated levels of β-sheets. When organic acids were added in increasing levels, corresponding increases in the quantities of α-helices in the protein were observed. Alveography showed that zein-based doughs prepared with dilute organic acids retained gases well and that the concentration of dilute organic acids influenced dough distensibility (biaxial extensibility) and stability (the ability of the dough to retain gas). Low concentration of acids (0.7 and 1.3%) increased dough stability to levels similar to that of strong wheat flour, 103 mm H2O, but higher concentrations of acids (5.4%) led to a marked reduction in dough stability. Thus, by increasing zein dough functionality to such an extent, the apparent usefulness of the doughs and their ability to retain gases produced during fermentation is reduced. Simple distensibility tests on zein doughs showed that added organic acids promoted ‘clumping’ of the fine protein fibrils in the dough network into pronounced fibres. This would account for the decreased dough stability when high levels (5.4%) of organic acids were used. Baking trials with zein doughs were not successful as adequate leavening was impossible without an acid-tolerant leavening agent.
It is believed that dilute organic acids influence the rheological properties of zein dough by creating a positively charged environment, in which the protein is partially solubilized. The higher the level of organic acid used, the greater the positive net charge and the more pronounced the effect on the protein network structure. Organic acids could also improve fluidity of the zein dough by acting as plasticizers.
From this work it can be seen that although a protein network is present in all zein-based doughs, the ability of this network to retain gases is dependant on the level of organic acids present. The functional properties of zein-doughs made with low levels of organic acids (0.7 and 1.3%) shows potential in the production of gluten-free bread for individuals suffering from coeliac disease.Dissertation (MSc)--University of Pretoria, 2013.
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Crockett, Rachel Lynn. "The Physicochemical Properties of Gluten-Free Dough with the Addition of Hydrocolloids and Proteins." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1251825675.
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Weegels, Peter Louis. "Depolymerisation and re-polymerisation of wheat glutenin during dough processing and effects of low Mâ†r wheat proteins." Thesis, King's College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320464.
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Danielson, Erin Marie. "Addition of Soybean Lipoxygenase to All-Purpose Flour and its Effects on Dough Gluten Strength and Bread Quality." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/33595.
Анотація:
The goal of this research is to determine the effects of added soybean lipoxygenase (LOX) on bread dough rheological properties and physical properties of bread loaves compared to controls, and to determine sensory attributes of bread loaves using quantitative descriptive analysis (QDA). Protein fractions were obtained through the use of isoelectric precipitation. The pH 4.8 precipitate was found to yield the greatest LOX activity when compared with other fractions (p<0.05). The addition of pH 4.8 precipitate improved rheological properties of bread dough, examined in a farinograph, when compared to the all-purpose control (p<0.05). Addition of soy flour also increased the gluten strength of all-purpose flour (p<0.05). The addition of pH 4.8 precipitate to all-purpose flour did not improve bread loaf volume or texture. Sensory panelists described pH 4.8 supplemented bread as having firmer crumb when compared with controls (p<0.05). There were slight color differences among the loaves. The crust and crumb of bread flour loaves was lighter in color than any other sample. It was concluded that the addition of pH 4.8 precipitate to all-purpose flour greatly improved the rheological properties when compared with all-purpose flour alone.Master of Science
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Yip, Hopi, of Western Sydney Hawkesbury University, and Faculty of Science and Technology. "Genetic manipulation of baker's yeast for improved maltose utilisation." THESIS_FSTA_SFS_Yip_H.xml, 1999. http://handle.uws.edu.au:8081/1959.7/223.
Анотація:
Two yeast/E.coli shuttle vector plasmids were studied in 1994, termed pIBIDB and pBP33. According to this study, each plasmid should contain at least one ADH2UAS (upstream activation sequence in the alcohol dehydrogenase 2 gene) insert. In the present study, the constructed plasmids were analysed and transformed into laboratory strain yeast. The aim of this project was to identify the orientation, quantity and quality of the insert in the selected plasmids. Methods such as restriction analysis, polymerase chained reaction (PCR), sequencing, plate assays and enzyme assays were used to identify and evaluate the novel inserts. The data presented in this thesis suggest the inserted ADH2UAS fragment did enhance the production of maltose permease and maltase when the transformants were cultivated in maltose and ethanol-glycerol medium. The results suggested that transformants containing two inserts of ADH2UAS had a greater influence on the transformants than a single insert. But the inserts within the vectors and in transformed laboratory stain yeast appeared unstable. This could be due to the method used for plasmid construction and the storage condition of the transformantsMaster of Science (Hons)
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Cropper, Sherrill Lyne. "The influence of native wheat lipids on the rheological properties and microstructure of dough and bread." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/18924.
Анотація:
Doctor of PhilosophyDepartment of Grain Science and Industry
Hulya Dogan
Jon Faubion
Bread quality and final crumb grain are reflective of the ability for wheat flour dough to retain and stabilize gas cells during the baking process. The visco-elastic properties of dough allow for the incorporation of air cells and expansion during fermentation and baking. The gluten-starch matrix provides the backbone support. However, following the end of proofing and during the beginning of baking, the structure weakens due to over-extension and expansion and the matrix begins to separate and eventually break down. Native wheat lipids, which are found in small quantities in wheat flour, provide a secondary support for gas cell stabilization because of their amphiphilic characteristics and ability to move to the interface and form condensed monolayers. The objectives of this research were to evaluate the influence of native wheat lipids on the rheological properties of dough and the microstructure of bread. Native wheat lipids were extracted from straight-grade flour and separated into total, free, bound, nonpolar, glycolipids, and phospholipids using solid-phase extraction (SPE) with polar and nonpolar solvents. Defatted flour was reconstituted using each lipid fraction at a range of levels between 0.2% and 2.8%. Dough and bread were made following AACC Method 10-10.03. Rheological testing of the dough and evaluation of the microstructure of the bread was conducted using small and large deformation testing, C-Cell imaging, and x-ray microtomography analysis to determine changes in visco-elastic properties and gas cell structure and distribution. Rheological assessment through small amplitude oscillatory measurements demonstrated that nonpolar, phospholipids, and glycolipid fractions had a greater interaction with both proteins and starch in the matrix, creating weaker dough. Nonpolar, phospholipids, and glycolipids, varied in their ability to stabilize gas cells as determined by strain hardening index. C-Cell imaging and x-ray microtomograpy testing found that treatments containing higher concentrations of polar lipids (glycolipids and phospholipids) had a greater effect on overall loaf volume, cell size, and distribution. This illustrates that level and type of native wheat lipids influence the visco-elastic properties of dough and gas cell size, distribution, cell wall thickness, and cell stability in bread.
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Рябець, Я. Ю. "Розробка проєкту хлібозаводу з установкою 3-х печей Г4-ХПН-25, впровадивши прискорену технологію виробництва хлібобулочних виробів, передбачивши в асортименті сухарні вироби". Thesis, Чернігів, 2021. http://ir.stu.cn.ua/123456789/23250.
Анотація:
Рябець, Я. Ю. Розробка проєкту хлібозаводу з установкою 3-х печей Г4-ХПН-25, впровадивши прискорену технологію виробництва хлібобулочних виробів, передбачивши в асортименті сухарні вироби : випускна кваліфікаційна робота : 181 «Харчові технології» / Я. Ю. Рябець ; керівник роботи К. М. Іваненко ; НУ "Чернігівська політехніка", кафедра харчових технологій. – Чернігів, 2021. – 132 с.Тема дипломного проєкту: «Розробити проєкт хлібозаводу з установкою 3-х печей Г4-ХПН-25, впровадивши прискорену технологію виробництва хлібобулочних виробів, передбачивши в асортименті сухарні вироби». Умовою дипломного проєкту передбачений наступний асортимент виробів: 1) Хліб слов’янський подовий масою 0,84 кг; 2) Витушка бериславська масою 0,4 кг; 3) Сухарі київські вагові. В дипломному проєкті наведені розрахунки продуктивності та потужності печей, пофазних та виробничих рецептур, вихід виробів, норми витрати сировини, підбір технологічного обладнання. Дипломний проєкт містить розрахунки санітарно-технічної та енергетичної частини. В технологічних процесах, що пропонуються проєктом застосовані сучасні технології виробництва хлібобулочних виробів. Містить техніко-економічні розрахунки ефективності будівництва даного проєкту.
Theme of the diploma project: " To develop the project of a bakery with installation of 3 ovens Г4-ХПН-25, having introduced the accelerated technology of production of bakery products, having provided in assortment crackers". The condition of the diploma project is the following assortment of products: 1) Bread Slavic horseradish weighing 0.84 kg; 2) Beryl wax with a weight of 0.4 kg; 3) Kiev hardwoods. In the thesis project presented calculations of performance and capacity furnaces pofaznyh recipes and production output of products, rates of consumption of raw materials, process equipment selection. Diploma project contains some sanitary and energy parts. In industrial processes proposed project used modern technologies of production of bakery products. Provides technical and economic analysis of efficiency of the construction project.
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Almonte, M. Theresa. "Effects of dough mixing and relaxation on the protein solubility and composition of two diverse bread wheats." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ32898.pdf.
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Bell, Ruth Mary. "Extraction of arabinoxylan from animal feed and investigations into its functionality as an ingredient in bread dough." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/extraction-of-arabinoxylan-from-animal-feed-and-investigations-into-its-functionality-as-an-ingredient-in-bread-dough(a234da96-130a-45ac-912f-cbafb7f69880).html.
Анотація:
Arabinoxylans (AX’s) are the predominant non-starch polysaccharides found in the structural matrix of cell walls in wheat grains, being present in large quantities in wheat bran, accounting for up to 25% of its composition. Their physicochemical properties define their functionality which can be beneficial in cereal-based products such as bread, where their addition could enhance the gluten matrix responsible for the aerated structure and quality of bread. Bioethanol production has grown rapidly, however, to be economically viable, cereal-derived first generation biorefineries need to adopt the process integration approaches employed in petrochemical refineries, and exploit the interaction opportunities arising from multiple product streams. A potential source of AX is its extraction from the wheat bran based low value animal feed produced as an end product of the bioethanol distillation process. The benefits of extraction are twofold, to enhance feed nutritional value by reducing fibre content and produce a high value product for use as a functional ingredient in the breadmaking industry. Extraction of AX involves precipitation with ethanol, giving opportunity for integration and economic extraction in the context of a bioethanol plant. Currently no commercial supply of AX is available in sufficient quantities to conduct functionality trials; therefore the objective of the current work was to study the feasibility of extracting AX from animal feed and, by developing a scaled-up extraction process based on that of Hollmann and Lindhauer (2005) and Du et al. (2009), to produce sufficient quantities to conduct functionality trials into its effects on the breadmaking process. Two animal feeds, representative of contrasting biorefinery operations, were used for AX extraction, Distillers’ Dried Grains with Solubles (DDGS) and C*Traffordgold®, with water and alkaline AX being extracted from each. Monosaccharide analysis of the feedstocks confirmed the presence of arabinoxylans, with DDGS containing 12.5% AX and TG 13% AX, with A/X ratios of 0.55 and 0.61, respectively. The purity of AX extracted at both lab scale and on scale up was consistent, with 29.5% and 23% extracted at lab scale and 30% and 25% extracted in the scaled up process for WEAX from DDGS and TG, respectively. The purity of AEAX was lower, with 18% and 14% at lab scale and 15% and 14% for scale up for DDGS and TG, respectively. The results indicate that the same purity of crude extract can be achieved at both lab and larger scale extraction, however lower yields and absolute yields were observed at scale up and anticipated to be due to the crude nature of the process, which needs further optimisation. Addition of crude AX extracts to bread dough gave insights into its effects and potential benefits and issues. The type and origin of AX was found to affect bread dough characteristics in different ways. WEAX from both DDGS and TG exhibited effects on all stages of the breadmaking process, by improving stability and reducing softening at mixing, and slowing proving allowing the dough to retain a better aerated structure, leading to an open aerated finished loaf structure. AEAX from both types of animal feed generally caused destabilization of gas cells and coalescence, resulting in loaves with a tighter crumb structure. The AX dosage appeared to have a non-linear effect, with some positive changes at 1% addition turning to negative changes when added at 2%. This work has provided insights into the functionality of AX in bread dough, and a process has been developed to allow greater than lab scale production of arabinoxylan. The effects of AX need to be understood more clearly to retain beneficial effects, whilst supressing detrimental ones, preferably while avoiding the need for extensive purification. The work supports the possibility for AX extracts to be produced commercially as bread ingredients that could enhance bread structure and nutritional quality, and provides an elegant solution for synergy between two wheat-based industries serving both the food and non-food needs of society.
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Khuzwayo, Thandiwe Amelia. "Improvement in maize bread quality through addition of pre-gelatinized starch, sourdough in combination with dough sheeting." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/57249.
Анотація:
Wheat bread is a staple food product that is not easily accessible to many people in sub-Saharan Africa as it is relatively expensive. This is due to the regions climatic conditions which are not generally suitable for wheat cultivation. Hence, most wheat has to be imported. Maize is potentially a suitable alternative for production of bread and other dough-based products since it is widely produced under diverse environments in sub-Saharan Africa. However, maize does not possess unique viscoelastic gas-holding properties like wheat.
The effects of dough sheeting on the quality of maize dough and bread were investigated. Dough sheeting in combination with maize flour starch pre-gelatinization, zein, sourdough fermented maize flour and surfactant (DATEM) addition were investigated. Dough sheeting is a simple technology that has been used for development of dough from wheat flour of low protein quality.
Dough sheeting of maize flour without pre-gelatinization produced a crumbly dough, whereas sheeting in combination with starch pre-gelatinization produced a cohesive dough with dramatically improved dough handling properties. Tensile tests showed development of a smoother texture on maize dough as the number of sheeting passes increased from 5 to 40.
Zein dough addition (mixed above its glass transition temperature in water) in combination with dough sheeting formed a more elastic maize dough. CLSM revealed intermingling of fibrils from the added zein within the maize dough which was presumably responsible for the improvement in viscoelastic properties of the composite. Alveography revealed that maize-zein doughs retained gases well but that increasing sheeting passes reduced stability and extensibility. Maize bread had undesirable cracks on the crust. With zein addition, there was a reduction in the cracks. DATEM addition improved bread crumb structure, preventing the formation of holes. This was thought to be due to hydrophobic and hydrophilic interactions between starch and protein of maize flour and the DATEM.
Dough sheeting in combination with sourdough addition and pre-gelatinized maize produced maize bread with improved loaf height. Stereomicroscopy of the crumb of maize sourdough bread showed a more continuous crumb structure. It is proposed that the improvement of maize bread by sourdough addition is due to the sourdough inducing softening and modification of starch, making dough less elastic but improved ability of the maize dough to trap carbon dioxide and withstand pressure of expanding gas.
The study shows that dough sheeting together with pre-gelatinization of some of the maize flour improves dough handling and functional properties of maize doughs when applied in combination with other treatments. The best combination for maize bread was found to be dough sheeting at 15 passes, pre-gelatinization together with addition of sourdough and DATEM. Dough sheeting in combination with pre-gelatinized maize flour, addition of maize sourdough and DATEM could form a relatively inexpensive and predominately natural way of producing gluten-free breads.Dissertation (MSc)--University of Pretoria, 2016.
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Zhang, Hua-Xiao. "Effects of flour proteins, dough rheological properties, and flour extraction rates on northern-style Chinese steamed bread making /." Search for this dissertation online, 2003. http://wwwlib.umi.com/cr/ksu/main.
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Jelena, Filipović. "Interakcija prehrambenih vlakana sa gradivnim materijama testa u postupku izrade pekarskih proizvoda snižene energije." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 2009. https://www.cris.uns.ac.rs/record.jsf?recordId=71247&source=NDLTD&language=en.
Анотація:
U radu je ispitana interakcija tri vrste komercijalnih prehrambenih vlakana (Fibrex, inulin HPX i inulin GR) sa strukturnim komponentama hlebnog testa. Na različitim pH vrednostima (pH 7, pH 5, pH 4 i pH 3) ispitane su fizikohemijske osobine vlakana, pri čemu Fibrex ima najveći kapacitet zadržavanja vode od 421% dok inulin GR najmanji od svega 4.2%. Na osnovu reološke osobina testa sa vlaknima u količini od 5 i 10% dobijen je uvid u interakciju vlakana sa proteinskim kompleksom i klajsterisanim skrobom. Reološke osobine hlebnog testa zavise od količine i vrste inkorporiranih vlakana dok pH vrednost vode za zames ima mali uticaj na ove pokazatelje. Dodatkom 5 i 10% fibrex-a i inulina HPX dobija se hleb dobrog kvaliteta, sa značajnim padom svarljivih ugljenih hidrata i promenjenog nutritivnog sastava koji ima osobine funkcionalne hrane pri čemu fibrex tamni boju a inulin HPX i GR vizuelno ne menja boju hleba u odnosu na hleb bez vlakana. Statistička obrada podataka je potvrdila pozitivan uticaj vlakana na testa u zamrznutom stanju. Koeficijenti diskriminacije pokazuju da je najveći uticaj vlakana na završnu fermentaciju testa je posle 1 dana (199.006 i 5.739), a pozitivan uticaj vlakana na zapreminu hleba izražen je posle 30 dana (9.416) a na kvalitet sredine posle 60 dana (.841). Termodinamičkim merenjima kinetike zamrzavanja/odmrzavanja testa sa vlaknima utvrđeno je da inulina GR doprinosi skraćenju postupka što potvrđuje koeficient determinacije R2 (0.966 i 0.981) dok testo sa fibrexom ima najmanji koeficijent determinacije R2 (0.939 i 0.951) što pokazuje da ovo vlakno najlošije utiče na kinetiku zamrzavanja/odmrzavanja. Kinetika zamrzavanja/odmrzavanja može se definisati matematičkim modelom koja odgovara jednačini sa kvadratnim polinom , odnosno jednačini za nestacionarni temperaturni profil sa kvadratnim članom Y= b0+b1*X +b2*X2.The interaction of three different commercialfibers (Fibrex, inulin HPX and inulin GR) withstructural elements of bread dough was tested.Physico/chemical fiber characteristics atdifferent pH values point that the greatestwater binding capacity (421%) is attributed tofibrex, contrary to the value of 4,2%experienced for inulin GR. Rheology of doughcontaining 0 to 10% of either fiber type provedthe insight in the interaction between fibersand proteins and also fibers and starch gels.Dough rheology is influenced the most by fibercharacteristics and incorporated quantity,contrary to pH value of water at mixing stage.Statistical data interpretation proved thepositive contribution of fibers on dough atfreezingDiscrimination coefficients are confirming that,on the whole, the greatest influence fibers haveon final proof after1 day of freezing (199.006and 5.739) and their beneficial influence isexperienced after 30 and 60 days of freezing onbread volume (9.416) and bread crumb quality(0.841), respectively. Thermodynamicmeasuring of freezing/thawing kinetics ofdough containing fibers point that inulin GR isbeneficial in shortening the procedure,confirmed by values for determinationcoefficient R² (0.966 and 0.981), contrary to thecontribution of Fibrex where the smallestvalues for those coefficients were experienced,R² (0.939 and 0.951 proving that fibrex is notcontributing to the freezing/thawing kinetics.Freezing/thawing kinetics can be adequatelydefined by the mathematical model of squarepolynomial, i.e. equation for the non stationarytemperature profile with square Y= b0+b1*X +b2*X2.Data presented in this thesis show that,understanding interactions between fibers anddough structure, by the addition of 5 or 10% ofeither Fibrex or inulin HPX, high quality breadattributed with a significant decrease ofdigestible carbohydrates and modified nutritivepattern accompanied with attributes offunctional food can be made, while Fibrex isadversly contributing to crumb colour contraryto inulin HPX and GR.
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Traynham, Toshiba Lynne. "Evaluation of extruded-expelled low-fat soybean flour in flour blends and the effects on bread and dough development." [Ames, Iowa : Iowa State University], 2006.
35
Pickett, Melissa M. "Study of gas cell stability during breadmaking using x-ray microtomography and dough rheology." Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1674.
36
Buche, François. "Influence de la formulation de pâtes de farine de blé sur leur consommation d'oxygène et leur production de dioxyde de carbone au cours du pétrissage et de la fermentation : Conséquences biochimiques et rhéologiques." Thesis, Paris, AgroParisTech, 2011. http://www.theses.fr/2011AGPT0033/document.
Анотація:
Le pétrissage et la fermentation des pâtes constituent deux étapes clé de la panification. Lors du pétrissage, l'oxygène incorporé à la pâte alimente en substrat oxydant les réactions d'oxydation, pour la plupart enzymatiques, conduisant au développement des réseaux de gluten et d'arabinoxylanes donnant à la pâte ses propriétés viscoélastiques et son aptitude à la rétention gazeuse. Lors de la fermentation, la production de dioxyde de carbone par la levure conditionne la levée du pâton. Un pétrin-fermenteur étanche, le sitoxygraphe, a été utilisé pour quantifier, à tout instant au cours du pétrissage et de la fermentation, la consommation d'oxygène et la production de dioxyde de carbone en distinguant la part de CO2 qui est retenue par la pâte de celle qui apparaît dans la phase gazeuse. Une modification de la formulation de la pâte de farine de blé – par l'ajout, seul ou en mélange, de levure, d'oses oxydases, de farine de fève ou de soja, de lipases – augmente sa consommation d'oxygène, et affecte sa teneur en acides gras polyinsaturés, son état d'agrégation des protéines et ses propriétés rhéologiques. Il existe, par exemple, une compétition pour l'utilisation de l'oxygène entre la levure, qui respire durant le pétrissage, et les oxydoréductases endogènes ou exogènes. Elle se traduit par une diminution des effets biochimiques et rhéologiques des oxydoréductases exogènes. L'utilisation d'atmosphères enrichies en oxygène en début de pétrissage devrait permettre de limiter ces compétitions et donc d'amplifier l'activité des oxydoréductases exogènesKneading and fermentation of dough are two key steps in bread making. During kneading, incorporated oxygen into dough supplies in oxidizing substrate oxidation reactions, most of them are enzymatic, leading to the development of gluten and arabinoxylans networks giving dough viscoelastic properties and its ability to gas retention. During fermentation, the production of carbon dioxide by yeast determines the volume increase of the dough. An airtight knerder-fermenter, the sitoxygraphe, has been used to quantify, at any moment during of kneading and fermentation, oxygen consumption and carbon dioxide production by distinguishing the part of CO2 that is retained by dough from that which appears in the gas phase. A modification of dough formulation prepared with wheat flour - by adding one or a mix of, yeast, oses oxidases, horse bean or soybean flour, lipases - increases oxygen consumption and affects its content of polyunsaturated fatty acids, its protein aggregation and its rheological properties. For example, there is a competition for the use of oxygen between the yeast, which breathes during kneading and endogenous or exogenous oxidoreductases. It results in a decrease of rheological and biochemical effects of exogenous oxidoreductases. The use of atmospheres enriched with oxygen at the beginning of kneading should allow limiting these competitions and amplifying exogenous oxidoreductases activity
37
Gan, Zhilin. "The structure and functional properties of gas cells in wheat bread dough with special reference to the use of wholemeal flour." Thesis, King's College London (University of London), 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242897.
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Matuda, Tatiana Guinoza. "Análise térmica da massa de pão francês durante os processos de congelamento e descongelamento: otimização do uso de aditivos." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-20082004-145227/.
Анотація:
O pão produzido de massa congelada tem sido aprimorado pelos avanços tecnológicos e diferentes formulações, porém ainda apresenta problemas como fermentação prolongada, baixo volume, textura e desempenho variados. O efeito do congelamento pode ser minimizado através do uso de aditivos e ingredientes adequados para a elaboração da massa. Entretanto o mecanismo de fortalecimento devido aos aditivos como, por exemplo, o emulsificante não é completamente conhecido. A análise térmica é uma ferramenta útil para pesquisa, desenvolvimento e controle de qualidade de alimentos, pois permite o estudo das alterações na sua estrutura durante um tratamento térmico. O objetivo do trabalho foi estudar a influência do uso de aditivos de panificação sobre o comportamento da massa de pão francês após ciclos de congelamento e descongelamento. O trabalho experimental foi dividido em quatro etapas: na primeira, diferentes formulações foram produzidas com os componentes estearoil-2-lactil lactato de cálcio (CSL), polisorbato 80 (PS80) e gordura vegetal hidrogenada (GVH); na segunda etapa foi realizado um projeto de mistura com três componentes (CSL, PS80 e ésteres de ácido diacetil tartárico de mono e diglicerídio - DATEM); na terceira foi estudada a influência do ácido ascórbico sobre as características reológicas e os eventos determinados através de Calorimetria Exploratória Diferencial (DSC) afim de otimizar o uso destes aditivos em massas congeladas. A análise térmica mostrou-se adequada aos eventos de congelamento e descongelamento, porém não em relação aos eventos relativos aos aquecimentos. A resistência à extensão bem como a extensibilidade da massa foram influenciadas pelo tempo de armazenamento congelado. Na quarta etapa do projeto, foram produzidos pães franceses à partir de massas com a mistura (0,3 % de PS80 e 0,2 % de DATEM sobre a farinha de trigo) e dois níveis de ácido ascórbico (0 e 200 ppm). Volume específico, perfil de textura, conteúdo de água e medida da produção de gás e tolerância da massa durante a fermentação foram determinados. Os pães produzidos com a adição de ácido ascórbico apresentaram maiores volumes específicos e menores valores para os parâmetros de textura dos pães (firmeza, elasticidade, coesividade e mastigabilidade).Bread produced from frozen dough has been improved due to technological advances and formulation, however it still presents problems like long proofing, low specific volume, varied texture and performance. The effect of freezing can be minimized by use of additives and adequate ingredients. The mechanism of dough strengthening due to use of additives, such as emulsifiers, is not fully understood. Thermal analysis is a useful tool for food research, development and quality control, because it provides information on food structural changes during thermal treatment. The goal of this research is to study the influence of additives in bread making on French bread dough after a freeze-thaw cycles. The experimental part consists of four parts: in the first, different formulations were produced with the components calcium stearoyl-2-lactylate (CSL), polysorbate 80 (PS80) and vegetable shortening (VGH); in the second, a mixture design with three components (CSL, PS80 and diacetyl tartaric esters of mono and digliceride DATEM) was made; in the third, influence of ascorbic acid was studied on rheological measurement and events determined by differential scanning calorimetry (DSC) to optimize the use of additives on frozen dough. Thermal analysis was adequate for the freeze-thaw events, however not for the heating events. Resistance to extension and dough extensibility were influenced by storage time. In the fourth part, French breads from frozen dough were produced with the mixture (0,3 % of PS80 and 0,2 % of DATEM in flour basis) and two levels of ascorbic acid. Specific volume, texture profile, water content, gas production and mass tolerance during proofing were determined. Breads made with ascorbic acid addition presented a higher specific volume and lower values for texture profile (firmness, springiness, cohesiveness and chewiness).
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Fontaine, Joran. "Effet de la géométrie des pétrins sur l'alvéolation et la texturation de pâte à pain." Electronic Thesis or Diss., Nantes, Ecole nationale vétérinaire, 2019. http://www.theses.fr/2019ONIR127F.
Анотація:
Dans le procédé de panification, la phase de pétrissage est une des plus importantes et va conditionner en grande partie la structure finale du produit céréalier. Ce travail s’est intéressé à l’impact de la géométrie du pétrin et des conditions opératoires sur les caractéristiques de la pâte à pain. Pour ce faire, quatre pétrins de deux géométries (simple et double outil) et de deux échelles (laboratoire et industrielle) ont été étudiés. Ces pétrins ont été définis grâce à des facteurs (puissance, cisaillement, mélange etc.) les caractérisant. L’étude a permis de quantifier le taux de cisaillement par différentes approches (échelle globale à locale) et de mettre en relation l’influence de la géométrie sur cette grandeur. Les caractéristiques de la pâte ont été étudiés principalement selon deux paramètres, l’aération et la structuration. Ces deux paramètres évoluent avec les phases du pétrissage et les conditions opératoires. L’impact du pétrissage sur les liaisons chimiques a été étudié par Microscopie Confocale à Balayage Laser (MCBL) et par les spectroscopies vibrationnelles Proche Infrarouge et Raman. Les caractéristiques hysicochimiques des pâtes ont ensuite été étudiées à un même niveau de pétrissage en variant les entrefers au fond de cuve, à la paroi de la cuve et inter-outil et sur tous les pétrins, mettant en évidence un effet de l’échelle et de la géométrie. L’ensemble des résultats a permis de déterminer les paramètres clefs qui conditionnent la structure du réseau de gluten formé au pétrissage. Enfin, un indice de performance de pétrissage a été développé afin de pouvoir classer les pétrins selon leur efficacité de mélange et leur rendement énergétiqueIn the bread-making process, the mixing phase is one of the most important and will largely determine the final structure of the cereal product. This work focused on the impact of the geometry of the mixer and the operating conditions on the characteristics of bread dough. To do so, four mixers of two geometries (single and double tool) and two scales (laboratory and industrial) were studied. These mixers were defined by factors (power, shear, mixing, etc.) characterizing them. The study quantified the shear rate using different approaches (global to local scale) and related the influence of geometry on this magnitude.The characteristics of the dough were studied mainly according to two parameters, aeration and structuring. These two parameters change with the phases of kneading and the operating conditions. The impact of kneading on chemical bonds was studied by Confocal Laser Scanning Microscopy (CLSM) and by Near Infrared and Raman vibration spectroscopy. The physico-chemical characteristics of the doughs were then studied at the same kneading level by varying the air gaps at the bottom of the tank, at the tank wall and between tools on all kneaders, highlighting an effect of scale and geometry. All the results made it possible to determine the key parameters that condition the structure of the gluten network formed during kneading. Finally, a kneading performance index has been developed in order to classify kneaders according to their mixing efficiency and energy efficiency
40
Yip, Hopi. "Genetic manipulation of baker's yeast for improved maltose utilisation." Thesis, [Richmond, N.S.W.] : Centre for Biostructural and Biomolecular Resarch, Faculty of Science and Technolocy, University of Western Sydney, Hawkesbury, 1999. http://handle.uws.edu.au:8081/1959.7/223.
Анотація:
Two yeast/E.coli shuttle vector plasmids were studied in 1994, termed pIBIDB and pBP33. According to this study, each plasmid should contain at least one ADH2UAS (upstream activation sequence in the alcohol dehydrogenase 2 gene) insert. In the present study, the constructed plasmids were analysed and transformed into laboratory strain yeast. The aim of this project was to identify the orientation, quantity and quality of the insert in the selected plasmids. Methods such as restriction analysis, polymerase chained reaction (PCR), sequencing, plate assays and enzyme assays were used to identify and evaluate the novel inserts. The data presented in this thesis suggest the inserted ADH2UAS fragment did enhance the production of maltose permease and maltase when the transformants were cultivated in maltose and ethanol-glycerol medium. The results suggested that transformants containing two inserts of ADH2UAS had a greater influence on the transformants than a single insert. But the inserts within the vectors and in transformed laboratory stain yeast appeared unstable. This could be due to the method used for plasmid construction and the storage condition of the transformants
41
Slađana, Rakita. "Evaluacija kvaliteta pšeničnih sorti sa teritorije Vojvodine procenom reoloških karakteristika testa." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 2018. https://www.cris.uns.ac.rs/record.jsf?recordId=105545&source=NDLTD&language=en.
Анотація:
Uprkos brojnim tradicionalnim reološkim metodama koje se već dugi niz godina koriste u proceni kvaliteta brašna, postoji potreba za razvijanjem novih metoda, pomoću kojih bi se za kratko vreme i uz ograničenu količinu uzorka mogao uspešno predvideti kvalitet brašna i gotovog proizvoda. Na taj način selekcionerima bi bila omogućena procena tehnološkog kvaliteta linija pšenice čija je količina ograničena, dok bi se mlinarima obezbedio brz metod procene kvaliteta. Osnovni cilj istraživanja ove disertacije je ispitivanje mogućnosti primene novog reološkog uređaja glutopika u proceni kvaliteta brašna i finalnog proizvoda – hleba, kao i mogućnost zamene tradicionalnih dugotrajnih metoda novom reološkom metodom.Kako bi se ispitale i iskoristile mogućnosti reološkog uređaja glutopik za procenu kvaliteta pšeničnog brašna definisani su optimalni uslovi merenja koji su podrazumevali upotrebu NaCl kao rastvarača i zadate parametre temperature (36 °C), obrtne brzine mešača (2700 rpm) i odnos brašna i rastvarača (8,5/9,5). Zabeležen je veliki broj korelacija između parametara glutopika i empirijskih reoloških pokazatelja kvaliteta brašna i testa. Takođe je utvrđena značajna korelacija između parametara glutopika i indikatora kvaliteta hleba u pogledu specifične zapremine i teksturnih karakteristika sredine hleba. Na osnovu parametara dobijenih merenjem na glutopiku definisane su granične vrednosti. Ustanovljeno je da se primenom glutopik metode može izvršiti klasifikacija sorti pšenice prema kvalitetu. Pored toga, utvrđeno je da glutopik ima veliki potencijal da zameni alveograf u proceni kvaliteta brašna u mlinarskoj i pekarskoj industriji. Reološki parametri koji zavise od sadržaja proteina kao što su moć upijanja vode i žilavost testa uspešno se mogu predvideti pomoću parametara glutopika. Primenom glutopik metode postignuta je umerena predikcija specifične zapremine hleba, dok je postignuta veoma dobra predikcija teksturnih karakteristika sredine hleba.U okviru ove disertacije je ispitan uticaj sorte i lokaliteta na tehnološki kvalitet brašna pšenice kako bi se utvrdilo koja od ispitivanih sorti ispoljava ujednačen kvalitet u različitim mikroklimatskim uslovima tokom dve proizvodne godine. U obe proizvodne godine pokazatelji kvaliteta brašna su dominantno sortno određeni, pri čemu je zabeležen određeni uticaj mikroklimatskih faktora na lokalitetima gajenja. Odličan i najstabilniji kvalitet brašna u 2011. godini je imala sorta Gordana koja je pokazala najveću adaptabilnost na mikroklimatske uslove. Apač je uniformno imao najlošiji kvalitet duž svih ispitivanih lokaliteta. Domaće sorte su u 2012. godini imale promenljiv kvalitet u zavisnosti od lokaliteta gajenja. Hlebove proizvedene od domaćih pšeničnih sorti je karakterisala velika zapremina, rastresita struktura sredine sa izraženim velikim porama i mala čvrstoća sredine, dok je hleb proizveden od sorte Apač imao malu zapreminu, zbijenu strukturu sredine hleba sa velikim brojem malih pora kao posledicu velike čvrstoće. Dobra predikcija kvaliteta hleba od brašna iz 2011. godine je postignuta primenom jednog reološkog pokazatelja kvaliteta, dok je za uspešnu predikciju kvaliteta hleba od brašna iz 2012. godine neophodno izvesti nekoliko različitih reoloških merenja.Analizom tehnološkog kvaliteta brašna pšenice različitih sorti gajenih na različitim lokalitetima iz tri proizvodne godine zabeležene su velike varijacije u kvalitetu brašna i hleba na ispitivanim lokalitetima i u proizvodnim godinama, što jasno ukazuje na značajan uticaj interakcija između sortimenta i uslova gajenja (lokaliteta i godina), kao i značaj ispitivanja ovih interakcija i razvoja strategija koje imaju za cilj smanjenje uticaja spoljašnjih faktora na kvalitet pšenice.Regardless the fact that numerous traditional rheological methods have been used for many years in the flour quality assessment, there is a need for developing new methods, which could, in a short time, and with a limited amount of sample, successfully predict the quality of flour and finished products. In this way, wheat breeders would be able to evaluate the technological quality of the wheat lines with a restricted sample quantity, while the millers would be provided with a quick method of the quality evaluation. The main goal of the research of this dissertation was to examine the possibility of using a new rheological device GlutoPeak in the quality evaluation of flour and final product – bread, as well as the possibility of replacing traditional time-consuming methods with a new rheological test.In order to examine the possibility of using a GlutoPeak rheological device for the flour quality evaluation, the optimal measurement conditions were defined and included the use of NaCl as a solvent, the rotational speed of the mixer (2700 rpm), temperature (36 °C), the ratio of flour and solvent (8.5/9.5). Numerous correlations between GlutoPeak indices and empirical rheological parameters of dough behaviour were reported in this study. Significant correations were also observed between GlutoPeak parameters and bread specific volume and breadcrumb textural properties. The limit values were defined according to the GlutoPeak parameters values. Moreover, it was found that the GlutoPeak test could be used for wheat variety diferentiation according to the quality and has a great potential to replace Alveograph in the flour quality assessment in the milling and bakery industries. Parameters which depends on the protein content, such as, flour water absorption and dough tenacity, was successfully predicted by using parameters derived from GlutoPeak tester. A moderate prediction of loaf specific volume was achieved, while a very good prediction of breadcrumb textural characteristics was accomplished with the GlutoPeak parameters.In addition, the influence of genotype and growing location on flour quality was examined in order to determine which of the tested varieties exhibited uniform quality accross different microclimatic conditions in two production years. It was revealed that in both production years flour quality indicators were predominantly influenced by genotype, with a certain influence of microclimate factors on the growing locations. Gordana variety showed excellent and uniform quality with the highest adaptability to microclimate conditions in year 2011. Apache variety showed uniformly poor quality across all tested locations. In year 2012 domestic varieties exhibited variable quality depending on the growing locations. Bread produced from domestic wheat varieties was characterized by a large volume, loose breadcrumb structure with pronounced large pores and low hardness, while the bread produced from Apache variety had a small volume, dense breadcrumb structure with a large number of small pores as a result of high breadcrumb hardness. The quality of bread produced from wheat flour from year 2011 was well predicted based on one rheological quality parameter. On the other hand, several different rheological measurements was performed to successfully predict the quality of bread produced from wheat flour from 2012 year.By analyzing the technological quality of wheat flour of different varieties cultivated at different locations from three production years, large variations in the quality of flour and bread was recorded. The variations in flour and bread quality indicated the significant influence of interactions between the variety and growing conditions (locations and years), as well as the importance of examining these interactions and developing strategies aimed at reducing the impact of external factors on wheat quality.
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Abu-Ghoush, Mahmoud Hassan. "Effect of antimicrobial agents and dough conditioners on the shelf-life extension and quality of Arabic flat bread as determined by near infrared spectroscopy and texture analysis /." Search for this dissertation online, 2003. http://wwwlib.umi.com/cr/ksu/main.
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Matuda, Tatiana Guinoza. "Estudo do congelamento da massa de pão: determinação experimental das propriedades termofísicas e desempenho de panificação." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-17112008-114317/.
Анотація:
O conhecimento de propriedades termofísicas é importante na modelagem, na otimização e no projeto de equipamentos para processos como a fabricação de massa de pão congelada. Neste trabalho, as propriedades termofísicas condutividade térmica, difusividade térmica e calor específico foram determinadas experimentalmente ao longo do processo de congelamento da massa de pão, pois influenciam diretamente a cinética do processo que, por sua vez, determina a qualidade do pão produzido. Os resultados obtidos mostraram que algumas destas propriedades variaram em função do conteúdo inicial de água e principalmente devido à mudança da temperatura. O valor médio encontrado através da atividade de água das massas (aw = 0,950), para temperatura inicial de congelamento, pode explicar alguns desvios no ajuste dos dados experimentais a modelos disponíveis na literatura baseados na lei de Raoult, que são estritamente relacionados à fração de gelo formada. O uso combinado de goma guar e xantana reduziu a entalpia de fusão ao longo do tempo de armazenamento congelado (87,4 J.g-1 e 81,2 J.g-1 para a formulação sem gomas, não congelada e após 28 dias de armazenamento congelado; 84,4 J.g-1 e 76,9 J.g-1 para a formulação com 0,25% de goma guar e 0,25% de goma xantana na massa não congelada e após 28 dias de armazenamento congelado), indicando uma interação entre as gomas na capacidade de ligar água ao longo do tempo de congelamento. Porém, apesar do tempo de congelamento ter reduzido a entalpia de fusão, o processo de congelamento foi o principal fator na queda da taxa de fermentação e da produção de gás pelas leveduras independentemente do tempo de armazenamento congelado.The knowledge of thermophysical properties is important to model and optimize equipment design for frozen food processes. In this work, the thermophysical bread dough properties, such as, thermal conductivity, thermal diffusivity and specific heat were experimentally determined during freezing process, due to their influence on the kinetics process, and therefore on bread quality. The results showed that some properties varied according to the initial water content and mainly due to temperature changes. The average value of initial freezing temperature found by water activity (aw = 0.950) explains the deviations between experimental data and available models in the literature based on Raoults law, which is related to the ice mass fraction. The combined use of guar and xanthan gums reduced the fusion enthalpy along frozen storage time (87.4 J.g-1 and 81.2 J.g-1 for formulation without gum, non-frozen and after 28 frozen storage days; 84.4 J.g-1 and 76.9 J.g-1 for formulation with 0.25 % of guar gum and 0.25 % of xanthan gum in non-frozen and after 28 frozen storage days). It indicated the interaction between gums and their ability to hold water along frozen storage. Despite frozen storage reduced the fusion enthalpy, the freezing process itself was the main factor in the decrease in proofing rate and gas production by yeast cells.
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Rothman, Emma, and Jakob Erlandsson. "Potatisfibers inverkan på bröd : hur påverkas deg och bröd av potatisfiberns malningsgrad?" Thesis, Högskolan Kristianstad, Fakulteten för naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-19719.
Анотація:
Introduktion: Potatisfibern utgör ca 1 % av potatisens vikt och är en restprodukt vid tillverkningen av potatisstärkelse. Idag tillsätter flera välkända livsmedelsföretag potatisfiber i sina produkter. Den främsta anledningen till detta är för att fibern kan binda vätska 7–12 gånger sin egen vikt vilket kan ge en ekonomisk fördel. Syfte: Syftet med studien är att jämföra hur grovmalen respektive finmalen potatisfiber påverkar utvalda egenskaper i degen och brödet med särskilt fokus på brödets lagringsstabilitet. Metod: Pilottester Observationer av degegenskaper Mätning av vätskeförlust och brödvolym Instrumentell färgmätning med en kolorimeter Sensorisk bedömning av lagringsstabilitet Resultat: Pilottester av båda malningsgraderna av potatisfibern visade att vid en jämförelse av olika förbehandlingar så som skållning, blötläggning och tillsats direkt i degen, gav direkt tillsats av potatisfiber i degen flest fördelar, främst gällande mjukheten i degen. Vid observationen fanns en synlig färgskillnad mellan bröden med tillsatts potatisfiber och referensbrödet men detta säkerställdes inte vid den instrumentella färgmätningen. Brödens volym och vattenhållande förmåga påverkades inte av tillsats av potatisfiber. Den sensoriska bedömningen visade en upplevd torrhetskänsla för bröd med tillsatt potatisfiber (båda malningsgraderna) när det testades mot ett referensbröd. Den finmalda fibern påverkade lagringsstabiliteten mer än den grovmalda fibern gjorde. Slutsats: Malningsgraden gav inga märkbara skillnader på de utvalda deg- och brödegenskaperna. Potatisfiber hade inte tillräckligt stor påverkan på deg eller bröd för att antas vara lönsam att tillsätta vid brödbakning.Introduction: The potato fiber constitutes about 1 % of the weight of the potato and is a residual product in the manufacture of potato starch. Today, several well-known companies add potato fiber to their products. The main reason for this is because the fiber can bind liquid 7–12 times its own weight, which gives an economic advantage. Aim: The aim of this study is to investigate how the grind of potato fiber affects selected characteristics in dough and bread, with particularly focus on the storage stability of the bread. Method: Pilot tests Observations of dough characteristics Measure of water exchange and bread volume Instrumental color measurement with a colorimeter Sensory evaluation of storage stability Results: Pilot tests with both grinds of potato fiber showed that when comparing pre-treatments such as scalding, soaking and direct addition into the dough, a direct addition resulted with the most advantages, mainly regarding the softness of the dough. During the observations there was a visible difference in color between the potato fiber loaves and the reference loaf, which was not ensured in the instrumental color measurement. The volume and water retention in the bread was not affected by an addition of potato fiber. The sensory evaluation showed a perceived dryness for bread with added potato fiber (both grinds), when tested against a reference bread. The finely ground fiber affected the storage stability more than the coarse grounded fiber did. Conclusion: The grind gave no notable differences on the selected properties of dough and bread. The impact that grind had on dough characteristics and the finished bread were small.
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Негай, В. О. "Розробка технології хлібобулочних виробів з використанням плодів журавлини та цедри плодів цитрусових". Thesis, Чернігів, 2020. http://ir.stu.cn.ua/123456789/22817.
Анотація:
Негай, В. О. Розробка технології хлібобулочних виробів з використанням плодів журавлини та цедри плодів цитрусових : дипломна робота : 181 – Харчові технології / В. О. Негай ; керівник роботи Н. П. Буяльська ; НУ "Чернігівська політехніка", кафедра харчових технологій. – Чернігів, 2020. – 114 с.У кваліфікаційній роботі проведений літературний огляд щодо перспективності використання плодів журавлини та цедри плодів цитрусових у харчових технологіях, а саме у технології хлібобулочних виробів. Вивчено вплив плодів журавлини та харчових цитрусових волокон Herbacel AQ Plus на реологічні властивості тіста, протікання процесів бродіння, якість випечених виробів та процес черствіння. В представленій роботі наведені розрахунки продуктивності технологічної лінії для виробництва хліба пшеничного вищого сорту з додаванням харчових цитрусових волокон, розраховано виробничу рецептуру, підібрано технологічне обладнання, описано технологічну схему виробництва запропонованого виробу, розроблено план впровадження системи НАССР у виробництво запропонованого асортименту.
In the qualification work, a literature review was conducted on the prospects for the use of cranberries and citrus peels in food technology, namely in the technology of bakery products. The influence of cranberry fruits and dietary citrus fibers Herbacel AQ Plus on the rheological properties of the dough, the course of fermentation processes, the quality of baked goods and the process of hardening was studied. The paper presents calculations of the productivity of the technological line for the production of premium wheat bread with the addition of dietary citrus fibers, calculates the production recipe, selects technological equipment, describes the technological scheme of production of the proposed product, developed a plan to implement the HACCP system in the proposed range.
46
Elmehdi, Hussein Mohamed. "An ultrasonic investigation of the effect of voids on the mechanical properties of bread dough and the role of gas cells in determining the cellular structure of freeze-dried breadcrumb." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq62634.pdf.
47
Rühmkorf, Christine [Verfasser], Rudi F. [Akademischer Betreuer] Vogel, and Peter [Akademischer Betreuer] Köhler. "Molecular background, in situ production and structure, function relation of bacterial exopolysaccharides in gluten-free dough and bread / Christine Rühmkorf. Gutachter: Rudi F. Vogel ; Peter Köhler. Betreuer: Rudi F. Vogel." München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1035766566/34.
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Resende, Fabrício de Souza. "Efeito do congelamento sobre a microestrutura da massa do pão." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-04112011-151945/.
Анотація:
A qualidade global da massa de pão congelada por um longo período é um desafio para indústria de panificação. O uso de diferentes técnicas pode ajudar a explicar os danos sofridos à massa de pão durante o congelamento e armazenamento congelado. A presença de água na forma de cristais de gelo foi vista como a principal causa de defeitos à estrutura da massa. Gomas guar e xantana foram incorporadas às massas para contornar os danos causados pelo congelamento. Das análises térmicas conduzidas em calorímetro de varredura diferencial foi possível quantificar a quantidade de gelo presente na massa. A adição de (0,125 a 0,250) g/100g de goma guar e de (0,214 e 0,250) g/100g de goma xantana diminuíram os valores de entalpia na massa ao longo do armazenamento congelado. A fração de gelo foi menor e mais estável nas massas contendo (0,125 e 0,250) g/100g de goma guar ou xantana. O valor da atividade de água diminuiu nas massas contendo goma guar e com níveis mais altos de goma xantana, após o ciclo de congelamento e descongelamento e 170 dias de armazenamento. Alterações na estrutura das massas foram medidas e visualizadas pela análise de textura e por microscopia eletrônica de varredura (MEV). Adição de goma xantana e principalmente de goma guar às massas aumentaram a resistência à extensão após 170 dias de armazenamento congelado. A extensibilidade não foi influenciada pela adição de gomas e manteve estabilidade nos períodos de armazenamento estudados. A MEV ajudou a explicar os danos causados à rede de glúten pelos cristais de gelo ao longo do armazenamento congelado. A massa sem gomas apareceu com pequenos danos na rede de glúten com 21 dias de armazenamento e estes danos aumentaram progressivamente por até 170 dias, mostrando um glúten menos contínuo, mais rompido e separado dos grânulos de amido. As massas contendo gomas minimizaram, mas não evitaram os danos causados ao longo do armazenamento congelado.The global quality of the frozen bread dough for long periods of frozen storage is the challenge to bakery industry. The use of different techniques could help to explain the damages caused in the frozen dough during the freezing and along frozen storage time. The presence of water as ice crystals was the main cause of damage on the dough structure. In order to minimize the freezing damages, guar and xanthan gums were incorporated in the dough. From thermal analysis by DSC technique, the amount of ice present in the dough was determined. The addition of (0.125 to 0.250) g/100g guar gum and (0.214 and 0.250) g/100g xanthan gum presented lower values of fusion enthalpy. The addition of (0.125 and 0.250) g/100g of guar gum decreased or stabilized the frozen water content, suggesting minimal damage on the dough structure along frozen storage time. The water activity in the dough samples with guar gum and higher quantities of xanthan gum decreased after the freezing-thawed cycle and after a period of frozen storage of 170 days. The incorporation of xanthan gum and mainly the incorporation of guar gum increased the maximum resistance of the dough after 170 days. The extensibility was not affected by addition of gums along frozen storage time. The MEV technical helped to explain the damaged dough structure caused by ice crystals along frozen storage time. Dough samples without gums presented structure damage only after 21 days and increased after 170 days, resulting in less continuous gluten, more disrupted and separated from starch granules. The doughs with gums suffered less damage in the gluten matrix, but did not avoid the problems caused by frozen storage.
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Boitte, Jean-Baptiste. "Contribution à l’étude de systèmes divisés alimentaires par observation de microstructures au cours de traitements thermo-mécaniques." Thesis, Paris, AgroParisTech, 2012. http://www.theses.fr/2012AGPT0064/document.
Анотація:
Pour mettre en relation les propriétés rhéologiques et la structure méso/microscopique d'un système modèle ou complexe, l'utilisation de la rhéo-optique est indispensable. Nous avons donc développé une cellule d'observation sous cisaillement adaptée à la microscopie confocale. Ce dispositif, breveté et nommé RheOptiCAD®, permet le cisaillement contrôlé d'un échantillon quelconque placé entre 2 plans parallèles en translation. Grâce à un système à dépression, la mise en place de l'échantillon est simple et rapide tout en assurant des propriétés optiques répétables et reproductibles (planéité, parallélisme). Par ailleurs, la température au sein de l'échantillon peut être régulée de façon à imposer une contrainte thermique, cause de nombreuses modifications de la mésostructure d'un système alimentaire. La cellule d'observation sous cisaillement permet donc de suivre l'évolution et la dynamique des changements de structures conséquences d'un traitement thermo-mécanique imposé. Un logiciel de pilotage et d'acquisition des données a été développé pour rendre son utilisation plus conviviale. La validation du fonctionnement de l'outil et de ses fonctionnalités a tout d'abord été réalisée sans échantillon puis à l'aide d'un système modèle contenant des particules fluorescentes dont le mouvement était suivi. Par la suite, dans le but de tester les potentialités de ce nouvel outil tout en développant la méthodologie de son utilisation, et en particulier l'équilibre entre propriétés optiques et mécaniques des échantillons, nous avons travaillé avec de la pâte de farine. Ce système alimentaire bien connu et maîtrisé d'un point de vue rhéologique au laboratoire présente des caractéristiques intéressantes dans ce cadre. L'évolution du réseau de gluten au cours d'un cisaillement oscillatoire en fonction de la formulation de la pâte a été étudiée. Grâce à une analyse d'image basée sur la morphologie mathématique, nous avons pu mettre en évidence des changements de structures au cours du temps. De même, à l'aide des capacités thermiques de la cellule de cisaillement, nous avons étudié le positionnement et le mouvement des lipides endogènes à l'interface air-protéine lors de la fermentation. Notre cellule d'observation sous cisaillement constitue donc un nouvel outil de caractérisation dynamique de systèmes complexes couplant rhéologie et microscopie. Son optimisation principale réside dans la mise en place d'un capteur de force, mesurant les contraintes mises en jeu lors des déformations imposéesRheo-optic is a recent technique which can be used to create links between rheological properties and meso/microsctructures of model or complex (food) systems. A novel rheo-optical shearing device was designed for studying this relationships within complex food systems. The device has been build to be adapted on an inverted confocal microscope. Specifications of the shear cell are: a) a controlled translational shear between 2 parallel plates with three different motion modes (continuous, oscillatory, strain jump); b) a thermal control; and c) an observation on an inverted confocal microscope. Due to a vacuum system, the set up of an experiment is easy and fast ensuring reproducible optical properties (planarity, parallelism). Temperature, responsible of numerous modifications of structures in a food matrix, is also controlled. A piloting software allows an easy use of the shear cell. Validation of the motion modes has been carried out using a microgel, containing fluorescent probes (spheres) and tracking some of the particles. Next, in order to test and develop methods of observation under shear, taking into account the optical-mechanical balance, bread dough observation has been performed. Well known and described in the lab, bread dough is a dispersion of air bubbles and starch granules in a gluten network. Evolution on this gluten network depending on the formulation of the bread dough has been studied under oscillatory shearing. The composition effect on the microstructure and its evolution were observed and will be commented. Image analysis based on grayscale mathematical morphology has been carried out in order to try to quantify the rheological properties and microstructures. Finally, by a controlled increase of temperature, the growth of an air bubble in bread dough containing yeast was followed during proofing. The influence and the disposition of fat globules at the bubble air-protein interface along this growing process were followed. Thanks to the rheo-optical device, images of microstructures obtained under controlled shear are compared to their rheological behaviour
50
Altuna, Luz. "Efeito da adição de amido resistente de milho e enzimas sobre as propriedades da massa de pão e as propriedades físicas do pão de forma." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-13042016-111652/.
Анотація:
O amido resistente de milho (ARM) não é digerido em humanos fornecendo benefícios para a saúde tais como redução do colesterol, do índice glicêmico e fermentação no cólon. Porém, a substituição parcial de farinha de trigo (FT) por ARM em massa de pão resulta na diluição do glúten prejudicando a qualidade do produto. Massa de pão foi produzida com 12,5 g/100g de ARM e os efeitos das enzimas glicose-oxidase (Gox), tranglutaminase (TG) e xilanase (HE) na massa foram estudados. Massa produzida sem ARM e sem enzimas foi considerada padrão e massa produzida com ARM e sem enzimas foi considerada controle para comparação. Uma metodologia foi desenvolvida para medir o torque durante o amassamento em grande escala, utilizando um reômetro dinâmico adaptado. As propriedades reológicas foram avaliadas nos testes de medidas descritivas de textura, adesividade Chen-Hoseney, extensão uniaxial Kieffer, extensão biaxial e testes oscilatórios em reômetro. Pão produzido de acordo com as formulações padrão, controle e ótima foi avaliado com relação ao volume específico (VEP), firmeza do miolo, cor e análise sensorial para o atributo preferência. As três enzimas testadas influenciaram positivamente o torque máximo atingido durante o amassamento que variou entre (8,36 e 9,38) N m. Gox e TG apresentaram efeito positivo na altura máxima desenvolvida pela massa medida em reofermentógrafo enquanto que o efeito da HE foi negativo. Uma formulação com ARM e enzimas apresentou desempenho de panificação similar a massa padrão (altura máxima ajustada igual a (45,5 ± 3,9) mm), correspondente a adição de (4, 2,5 e 0,5) mg/100g de TG, Gox e HE respectivamente (ótima). A formulação ótima apresentou adesividade, trabalho de adesão, coesividade, dureza, resiliência, resistência à extensão e extensibilidade similares a massa padrão e diferentes da massa controle. As enzimas aumentaram o índice de strain hardening reduzido pela adição de ARM. Para o pão de forma, o VEP variou entre (3,16 e 3,64) cm3/g (diferença não significativa) e o pão produzido com a formulação ótima foi o mais escolhido como preferido. Durante o armazenamento por até 7 dias, o ARM diminuiu a taxa de envelhecimento do pão enquanto que as enzimas apresentaram efeito oposto. Em geral, a substituição parcial de FT por ARM reduziu a elasticidade da massa diminuindo a qualidade do pão enquanto que as enzimas minimizaram esse efeito.Resistant starch (RS) is not digested by humans providing benefits for health such as reduction of blood LDL cholesterol levels, reduction of post-prandial blood glucose and fermentation in the colon. However, partial replacement of wheat flour (WF) with RS prejudices bread quality due to gluten dilution. Dough was formulated with 12.5 g/100g of RS and the effects of the enzymes glucose-oxidase (Gox), tranglutaminase (TG) and xylanase (HE) were studied. Dough produced without RS or enzymes was considered as regular and dough produced with RS and without enzymes was considered as control for comparison. A methodology was developed to measure torque during dough mixing in large scale using a dynamic rheometer. With respect to dough rheology, tests performed included texture profile analysis, Chen-Hoseney stickiness, Kieffer uniaxial extension, biaxial extension and oscillatory tests in rheometer. Bread was produced from regular, control and optimum formulations and the quality was assessed concerning specific volume, firmness, color and preference by sensory panel. The three enzymes tested influenced positively the maximum torque during mixing which varied between (8.36 and 9.38) N m. Gox and TG showed positive effects on the maximum height developed by dough measured in rheofermentometer while HE showed a negative one. A formulation with RS and baking performance similar to regular dough was found (adjusted maximum height equal to (45.5 ± 3.9) mm), corresponding to (4, 2.5 and 0.5) mg/100g of TG, Gox and HE respectively (optimum). The optimum formulation showed stickiness, work of adhesion, cohesiveness, hardness, resilience, resistance to extension and extensibility, similar to the regular dough and statistically different from control dough. Strain hardening index was reduced by the addition of RS and increased by the addition of enzymes. Regarding bread tests, specific volume of bread varied between (3.16 e 3.64) cm3/g (not significant difference) and the bread produced with theoptimum dough was the most preferred by the sensory panel. During 7 days of storage, RS reduced the aging rate while enzymes had the opposite effect. In general, WF replacement by RS reduced dough elasticity affecting the bread quality while enzymes helped minimizing this effect.