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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Evaluacija kvaliteta pšeničnih sorti sa teritorije Vojvodine procenom reoloških karakteristika testa / Quality evaluation of wheat varieties from Vojvodina by assessing dough rheological properties

Rakita Slađana 11 January 2018 (has links)
<p>Uprkos brojnim tradicionalnim reolo&scaron;kim metodama koje se već dugi niz godina koriste u proceni kvaliteta bra&scaron;na, postoji potreba za razvijanjem novih metoda, pomoću kojih bi se za kratko vreme i uz ograničenu količinu uzorka mogao uspe&scaron;no predvideti kvalitet bra&scaron;na i gotovog proizvoda. Na taj način selekcionerima bi bila omogućena procena tehnolo&scaron;kog kvaliteta linija p&scaron;enice čija je količina ograničena, dok bi se mlinarima obezbedio brz metod procene kvaliteta. Osnovni cilj istraživanja ove disertacije je ispitivanje mogućnosti primene novog reolo&scaron;kog uređaja glutopika u proceni kvaliteta bra&scaron;na i finalnog proizvoda &ndash; hleba, kao i mogućnost zamene tradicionalnih dugotrajnih metoda novom reolo&scaron;kom metodom.<br />Kako bi se ispitale i iskoristile mogućnosti reolo&scaron;kog uređaja glutopik za procenu kvaliteta p&scaron;eničnog bra&scaron;na definisani su optimalni uslovi merenja koji su podrazumevali upotrebu NaCl kao rastvarača i zadate parametre temperature (36 &deg;C), obrtne brzine me&scaron;ača (2700 rpm) i odnos bra&scaron;na i rastvarača (8,5/9,5). Zabeležen je veliki broj korelacija između parametara glutopika i empirijskih reolo&scaron;kih pokazatelja kvaliteta bra&scaron;na 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 izvr&scaron;iti klasifikacija sorti p&scaron;enice prema kvalitetu. Pored toga, utvrđeno je da glutopik ima veliki potencijal da zameni alveograf u proceni kvaliteta bra&scaron;na u mlinarskoj i pekarskoj industriji. Reolo&scaron;ki parametri koji zavise od sadržaja proteina kao &scaron;to su moć upijanja vode i žilavost testa uspe&scaron;no 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.<br />U okviru ove disertacije je ispitan uticaj sorte i lokaliteta na tehnolo&scaron;ki kvalitet bra&scaron;na p&scaron;enice 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 bra&scaron;na su dominantno sortno određeni, pri čemu je zabeležen određeni uticaj mikroklimatskih faktora na lokalitetima gajenja. Odličan i najstabilniji kvalitet bra&scaron;na u 2011. godini je imala sorta Gordana koja je pokazala najveću adaptabilnost na mikroklimatske uslove. Apač je uniformno imao najlo&scaron;iji kvalitet duž svih ispitivanih lokaliteta. Domaće sorte su u 2012. godini imale promenljiv kvalitet u zavisnosti od lokaliteta gajenja. Hlebove proizvedene od domaćih p&scaron;eničnih 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 bra&scaron;na iz 2011. godine je postignuta primenom jednog reolo&scaron;kog pokazatelja kvaliteta, dok je za uspe&scaron;nu predikciju kvaliteta hleba od bra&scaron;na iz 2012. godine neophodno izvesti nekoliko različitih reolo&scaron;kih merenja.<br />Analizom tehnolo&scaron;kog kvaliteta bra&scaron;na p&scaron;enice različitih sorti gajenih na različitim lokalitetima iz tri proizvodne godine zabeležene su velike varijacije u kvalitetu bra&scaron;na i hleba na ispitivanim lokalitetima i u proizvodnim godinama, &scaron;to 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 spolja&scaron;njih faktora na kvalitet p&scaron;enice.</p> / <p>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 &ndash; bread, as well as the possibility of replacing traditional time-consuming methods with a new rheological test.<br />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 &deg;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.<br />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.<br />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.</p>
62

Análise térmica da massa de pão francês durante os processos de congelamento e descongelamento: otimização do uso de aditivos. / Thermal analysis of French bread dough during freezing and thawing processes.

Matuda, Tatiana Guinoza 22 April 2004 (has links)
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).
63

Yeast metabolism in fresh and frozen dough : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand

Miller, Simon Derek Unknown Date (has links)
Author also know as S M Loveday / Fresh bakery products have a very short shelf life, which limits the extent to which manufacturing can be centralised. Frozen doughs are relatively stable and can be manufactured in large volumes, distributed and baked on-demand at the point of sale or consumption. With appropriate formulation and processing a shelf life of several months can be achieved.Shelf life is limited by a decline in proofing rate after thawing, which is attributed to a) the dough losing its ability to retain gas and b) insufficient gas production, i.e. yeast activity. The loss of shelf life is accelerated by delays between mixing and freezing, which allow yeast cells the chance to ferment carbohydrates.This work examined the reasons for insufficient gas production after thawing frozen dough and the effect of pre-freezing fermentation on shelf life. Literature data on yeast metabolite dynamics in fermenting dough were incomplete. In particular there were few data on the accumulation of ethanol, a major fermentation end product which can be injurious to yeast.Doughs were prepared in a domestic breadmaker using compressed yeast from a local manufacturer and analysed for glucose, fructose, sucrose, maltose and ethanol. Gas production after thawing declined within 48 hours of frozen storage. This was accelerated by 30 or 90 minutes of fermentation at 30;C prior to freezing.Sucrose was rapidly hydrolysed and yeast consumed glucose in preference to fructose. Maltose was not consumed while other sugars remained. Ethanol, accumulated from consumption of glucose and fructose, was produced in approximately equal amounts to CO2, indicating that yeast cells metabolised reductively.Glucose uptake in fermenting dough followed simple hyperbolic kinetics and fructose uptake was competitively inhibited by glucose. Mathematical modelling indicated that diffusion of sugars and ethanol in dough occurred quickly enough to eliminate solute gradients brought about by yeast metabolism.
64

Barley beta-glucan in bread: the journey from production to consumption

Moriartey, Stephanie 11 1900 (has links)
-Glucan is a soluble fibre shown to help regulate blood sugar and lower cholesterol. Incorporation into food, particularly bread, may affect -glucans physicochemical properties and health benefits. The journey of -glucan through the mixing, fermenting, baking, and storage of bread was evaluated, in terms of its solubility and viscosity under in vitro physiological conditions, at levels most likely to be presented to consumers (0.75, 1.0, 1.5 g -glucan/serving). Satiety and glycemic response measures, in addition to the quality and consumer acceptability of the bread, were also investigated. In dough, viscosity of the physiological extract was impacted by -glucan level, fermentation time, and endogenous flour enzymes. Fermentation decreased -glucan solubility indicating that the reduction in viscosity depends on both molecular degradation and solubility reduction. Dough rheological properties and microstructure, characterized using an oscillatory rheometer and fluorescence microscopy, respectively, showed that -glucan may interfere with the gluten network, though gluten addition may help improve this. The breads physical properties supported these observations, as -glucan decreased loaf volume and height, while gluten addition corrected this. Baking increased -glucan solubilization to 58-60%, compared to 9% in dough. Gluten addition increased solubility further (67-68%). Similar trends were seen for extract viscosity and were supported by fluorescence microscopy images. Storage at ambient, refrigeration and frozen conditions showed that bread with -glucan should be consumed fresh to maintain highest bread quality and -glucan solubility and viscosity. Bread with -glucan kept panelists full, longer. Reducing sugar release values implied that satiety may depend on digesta viscosity and/or rate of sugar release from the bread. Bread with -glucan produced the most leveled glucose curve; though areas under the 2 hr plasma glucose curves were similar. Consumers liked the 0.75 g -glucan/serving bread and the control more than the 1.5 g -glucan/serving bread, though provision of health information improved bread liking to similar values. The findings demonstrate that low solubility -glucan concentrate that gets solubilized upon baking is well suited for bakery applications and that a successful -glucan-fortified bread product is possible. Commercialization of bread fortified with -glucan would provide consumers an additional source of dietary fibre to assist them in coming closer to recommended daily intakes. / Food Science and Technology
65

Barley beta-glucan in bread: the journey from production to consumption

Moriartey, Stephanie Unknown Date
No description available.
66

Yeast metabolism in fresh and frozen dough : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand

Miller, Simon Derek Unknown Date (has links)
Author also know as S M Loveday / Fresh bakery products have a very short shelf life, which limits the extent to which manufacturing can be centralised. Frozen doughs are relatively stable and can be manufactured in large volumes, distributed and baked on-demand at the point of sale or consumption. With appropriate formulation and processing a shelf life of several months can be achieved.Shelf life is limited by a decline in proofing rate after thawing, which is attributed to a) the dough losing its ability to retain gas and b) insufficient gas production, i.e. yeast activity. The loss of shelf life is accelerated by delays between mixing and freezing, which allow yeast cells the chance to ferment carbohydrates.This work examined the reasons for insufficient gas production after thawing frozen dough and the effect of pre-freezing fermentation on shelf life. Literature data on yeast metabolite dynamics in fermenting dough were incomplete. In particular there were few data on the accumulation of ethanol, a major fermentation end product which can be injurious to yeast.Doughs were prepared in a domestic breadmaker using compressed yeast from a local manufacturer and analysed for glucose, fructose, sucrose, maltose and ethanol. Gas production after thawing declined within 48 hours of frozen storage. This was accelerated by 30 or 90 minutes of fermentation at 30;C prior to freezing.Sucrose was rapidly hydrolysed and yeast consumed glucose in preference to fructose. Maltose was not consumed while other sugars remained. Ethanol, accumulated from consumption of glucose and fructose, was produced in approximately equal amounts to CO2, indicating that yeast cells metabolised reductively.Glucose uptake in fermenting dough followed simple hyperbolic kinetics and fructose uptake was competitively inhibited by glucose. Mathematical modelling indicated that diffusion of sugars and ethanol in dough occurred quickly enough to eliminate solute gradients brought about by yeast metabolism.
67

Análise térmica da massa de pão francês durante os processos de congelamento e descongelamento: otimização do uso de aditivos. / Thermal analysis of French bread dough during freezing and thawing processes.

Tatiana Guinoza Matuda 22 April 2004 (has links)
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).
68

Correlating dough elastic recovery during sheeting to flour analyses and rheological properties

Ren, Danqiu January 1900 (has links)
Master of Science / Department of Grain Science and Industry / Jon M. Faubion / Charles E. Walker / In commercial bakeries, the baker expects to get the same bread loaf, including weight and size, after sheeting the same size dough piece. Doughs made from different flours have different elastic recoveries to a great extent, which has an effect on the dough’s size and density. Products made from differently elastic doughs can’t have the same shape and height. Weight may also be affected. The dough rheological behaviors of five flours and their blends having different chemical and physical properties were measured as were changes in thickness and snapback (thickness of the machined dough sheet relative to the roll gap) immediately following sheeting. Dough snapback was determined to be a function of both processing parameters, reduction ratio, and dough rest time, as well as different flour properties. The predication equation for dough snapback is based on multiple flour properties and sheeting conditions. Among the variables, Mixograph work, reduction ratio, and dough rest time were the main factors affecting the elastic characteristics of the doughs. Minimum snapback occurred with the weakest flour experiencing the longest rest time and the smallest reduction ratio. A 7-factor equation was found to be robust to predict the snapback of several flours, by combining Mixograph work, reduction ratio, dough rest time, Mixograph peak height and mixing time, Alveograph P/L, and protein content.
69

Using enzymes to improve frozen-dough bread quality

Lin, Hsing-I January 1900 (has links)
Master of Science / Department of Grain Science and Industry / Charles E. Walker / Potassium bromate is a well-known strong chemical oxidant. It was once widely used by the baking industry all over the world, especially for making frozen doughs. Since potassium bromate has been banned in many countries, many researchers have studied in this area to find a replacement. Ascorbic acid was often combined with potassium bromate in frozen dough making as an oxidant dough additive. In addition, ascorbic acid has different chemical oxidant activity, and its function in yeast leavened dough is not as strong as is potassium bromate. More dough additives have been found, such as enzymes. Enzymes play key roles in bread making. In recent years, enzyme usage in bread making has been increasing, especially for shelf-life extension. Based on the results from this research, potassium bromate use can be replaced by a combination of ascorbic acid and hemicellulase/endoxylanase. However, using hemicellulase/endoxylanase alone cannot benefit frozen dough quality such as finer crumb cell or increasing final bread volume. These experimental results also show that using a combination of ascorbic acid and hemicellulase/endoxylanase can delay the development of bread firmness (staling) after baking. As frozen storage time increased, the firmness of frozen dough bread increased, and the bread tended to have a coarser texture. Hence, larger and uneven grain cells reflect a gray or dark crumb color.
70

Mechano-chemical model study of the mixing process of water/flour mixtures in the context of the industrial wheat gluten-starch separation process / Etude modèle mécano-chimique de l’opération de malaxage des mélanges farine/eau dans le contexte du procédé industriel d’extraction du gluten de blé

Van der Mijnsbrugge, Adriaan 13 November 2015 (has links)
Le processus de séparation gluten-amidon est un des éléments clés du procédé de fractionnement de la farine de blé, pour la production d'amidon, de produits dérivés de l'amidon et de gluten de blé. Le procédé industriel comprend une étape de malaxage du mélange farine/eau, une étape de dilution de la pâte obtenue et enfin des opérations de séparation gluten-amidon par tamisage ou centrifugation. Le procédé industriel est très consommatoire en eau, et plusieurs flux d'eau sont recyclés des étapes situés en aval du procédé vers les étapes en amont comme la préparation et la dilution de la pâte. L'objective de cette étude était d'étudier l'impact de ces flux d'eau recyclés sur l'agglomération du gluten, et d'identifier les principaux paramètres du procédé qui influencent le rendement d'extraction du gluten. Basé sur l'échantillonnage de plusieurs flux d'eau de différentes usines, un composant clé de ces flux d'eau recyclée a été identifié. Les mécanismes de développement de la pâte ont été étudiés à l'échelle laboratoire en utilisant un mélangeur planétaire (P600). La présence du composant au niveau de l'étape de préparation de la pâte retarde sa cinétique de développement et augmente l'énergie mécanique à fournir pour le développement. A l'échelle moléculaire ce composant ralentit la dépolymérisation des polymères de gluténine insolubles dans le SDS (UPP) de la farine lors du malaxage de la pâte. L'agglomération du gluten est contrariée par la présence de ce composé que ce soit au moment de la préparation de la pâte ou de sa dilution. Au cours de l'étape de dilution ce composé modifie chimiquement les arabinoxylanes de la farine, ce qui a un effet négatif très direct sur la capacité d'agglomération des protéines du gluten. Un paramètre de conduite de l'opération de malaxage a été identifié qui rend compte de la capacité d'agglomération du gluten (rendement du procédé) et de la distribution en taille des macromolécules de gluténines présentent dans le gluten extrait. Ce dernier paramètre est également sous l'influence de la composition en gluténines, codées par le locus Glu-1D du génome du blé. / The gluten-starch separation process is a key part of an industrial wheat fractionation plant, producing starch, starch-derived products, and vital wheat gluten. The industrial process consists of an initial flour hydration and dough mixing phase, a dough dilution step, followed by a gluten-starch separation by sieving or centrifugation. As this process is highly water consuming, several water streams are recycled from downstream unit operation of the process back upstream, to stages such as dough preparation and dough dilution. The aim of the present study was to investigate the impact of these recycled water streams on gluten agglomeration, and provide a further insight on the main process parameters influencing the gluten extraction yield. Based on the sampling of several water streams of different industrial plants, a key compound of these recycled water streams was characterized. A lab scale planetary mixer was used to study the dough development mechanisms. The presence of this compound at the dough preparation stage delayed dough development, as it increased the energy demand of the dough. On a molecular scale this constituent induced a delay of the depolymerization of SDS-insoluble glutenin (UPP) during dough mixing. Gluten agglomeration is impeded by this compound, both when present at the stage of dough preparation and dough dilution. The presence of this compound at the dough dilution stage chemically modified the flour arabinoxylans, impairing gluten agglomeration. A mixing parameter directly influencing both the molecular distribution of extracted gluten, as well as their agglomerating capacity, was proposed. The evolution of the molecular distribution of the extracted gluten with this mixing parameter was shown to be influenced by the wheat its glutenin composition, coded by the Glu-1D locus of the wheat genome.

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