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Development of a gluten-free commercial breadRakkar, Pardeep Singh January 2007 (has links)
Because of coeliac disease, some individuals cannot tolerate the protein gliadin present in the gluten fraction of wheat flour. From a commercial perspective, there is a need for the development of gluten-free bread with texture and flavour properties similar to the conventional wheat flour loaf. In the context of bread, the gluten component of wheat has a crucial role in stabilising the gas-cell structure and maintaining the rheological properties of the bread. The absence of gluten results in liquid batter rather than pre-baking dough, yielding baked bread with a crumbling texture, poor colour and other post-baking quality defects. The liquid batter cannot be processed on the existing production line of baking industry. The aim is to develop a gluten-free white loaf with similar quality characteristics to that of standard white bread on the existing processing lines at Quality Bakers New Zealand. Within this constraint, dough has to be produced with handling and moulding properties similar to those of conventional wheat flour loaves. This research focused on finding and implementing the gluten substitutes for the development of gluten-free high quality commercial bread. In this research, the independent variables were conventional wheat flour (the most basic control), other gluten-free flours from a variety of sources, starches, supplementary proteins, hydrocolloids such as hydroxypropylmethylcellulose (HPMC), hydrophilic psyllium husk, and enzymes such as microbial transglutaminase, glucose oxidase, lipase and fungal α-amylase. These ingredients were trialled in different combination and composition to produce a dough having ability to trap the carbon dioxide gas during proofing and baking to get high specific volume bread suitable for the Quality Bakers’ product range. After an essentially ‘shotgun’ approach to formulations, the research narrowed to a systematic and progressive variation of ingredients and their composition to develop workable commercial models. Ingredients and their compositions were manipulated according to the outcomes of the trials and their contribution in the formulations. The dependent variables included standard bakery rheological properties based on dough stickiness, dough extensibility, oven spring, bread specific volume, bread slice ability, and bread staling. A gelation system of the lower-temperature-stable hydrocolloid psyllium husk, the heat-stable hydrocolloid hydroxypropylmethylcellulose, maize starch, and potato starch was created to form industrial process able dough having ability to entrap carbon dioxide gas produced during proofing and initial phase of baking. Microbial transglutaminase was used to increase the cross linking of protein present in flours and supplemented for enhancing the dough-like structure and its gas entrapping abilities. A formulation has been discovered by this research for the development of high quality gluten-free commercial bread. The formulated bread has similar quality characteristics to that of standard white bread and can be produced on existing processing lines at Quality Bakers. Industrial process able gluten-free bread with similar quality characteristics to that of standard white bread can be formulated by using a specific combination of soy flour, maize starch, potato starch, yoghurt powder, milk protein, HPMC (K4M), psyllium husk, microbial transglutaminase, lipase, and fungal α-amylase. The significance of this research is mainly commercial and the insights gained may extend to other bakery items that could be used by coeliacs.
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Films and composites based on chitosan, wheat gluten or whey proteins -Their packaging related mechanical and barrier propertiesGällstedt, Mikael January 2004 (has links)
No description available.
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Dolda handikapp i förskolan : Hur upplever föräldrar och pedagoger att ha dessa barn i förskolan?Kristensson, Anna, Franzèn, Catarina January 2007 (has links)
I Läroplanen för förskolan står det: ”Omsorg om det enskilda barnets välbefinnande, trygghet, utveckling och lärande skall prägla arbetet i förskolan. Hänsyn skall tas till barnets olika förutsättningar och behov.” (s.4) Det är upp till pedagogerna att anpassa den pedagogiska verksamheten så den passar alla barn. Syftet med vårt arbete var att se hur pedagogerna upplever det att ha barn med dolda handikapp i barngruppen. Vi ville även ta reda på hur det byggs upp ett bra samarbetet med föräldrarna till barn med dolda handikapp, så att de känner en trygghet att lämna över ansvaret till förskolan. Vi har valt att använda oss av kvalitativa intervjuer med både pedagoger och föräldrar till barn med blödarsjuka och matallergi. Vårt resultat visar på att pedagogernas förhållningssätt är viktigt. Pedagogerna framhöll alla barn lika värde. Trots detta finns det saker som gör att barnet blir utpekat i barngruppen. Ett bra samarbete med föräldrarna kräver en öppen och rak kommunikation.
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Roles of carbohydrates and proteins in the staling of wheat flour tortillaAlviola, Juma Novie Ayap 15 May 2009 (has links)
Effects of enzymatic modification of starch, proteins and pentosans on dough and
tortilla properties were determined to establish the role of these wheat components in
tortilla staling. Starch, protein and pentosans were respectively modified with a-amylase,
protease and transglutaminase (TG), and xylanase. Tortillas were stored at 22oC and
evaluated for at least three weeks.
Amylase improved shelf-stability of tortillas, produced a significant amount of
dextrins and sugars, retarded decrease in amylose solubility, and weakened starch
granules. However, control and treated tortillas had similar degrees of amylopectin
crystallinity. Staling of tortillas appears to involve starch that reassociates into an
amorphous structure.
Micrographs of control dough had thin protein strands forming a continuous
matrix. Protease-treated dough had pieces of proteins in place of the continuous matrix,
while TG-treated dough had thicker protein strands that were heterogeneously
distributed. Both treatments resulted in shorter shelf-stability of tortillas. The
organization of protein in dough is important for dough structure and appears to impact
tortilla flexibility.
Protein solubility and SDS-PAGE results did not differentiate control and treated
dough or tortillas. The fractions or molecular weight distribution are not significant
determinants of protein functionality. Tertiary and quaternary protein structures of gluten
may be more related to tortilla shelf-stability. The 75 ppm xylanase treatment resulted in weaker tortilla structure and
significantly higher amounts of low molecular weight saccharides and sugars. Control
and the 25 ppm treatment sample had a similar shelf-stability and texture profile.
Pentosans may affect staling indirectly through the effect on gluten development.
Fresh tortillas have amylopectin in an amorphous state, while amylose is mostly
retrograded. The gluten matrix provides additional structure and flexibility to the tortilla.
Pentosans may or may not be attached to the gluten network. Upon storage, amylopectin
retrogrades and recrystallizes, firming the starch granules, resulting in firmer tortillas.
Starch hydrolysis decreased the rigid structure and plasticized polymers during storage.
It also reduced the restriction imposed by retrograded starch on gluten and allowed it
more flexibility. Thus, the flexibility of tortillas results from the combined
functionalities of amylose gel, amylopectin solidifying the starch granules during storage,
and the changed functionality of gluten after baking.
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Films and composites based on chitosan, wheat gluten or whey proteins -Their packaging related mechanical and barrier propertiesGällstedt, Mikael January 2004 (has links)
No description available.
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Dolda handikapp i förskolan : Hur upplever föräldrar och pedagoger att ha dessa barn i förskolan?Kristensson, Anna, Franzèn, Catarina January 2007 (has links)
<p>I Läroplanen för förskolan står det:</p><p>”Omsorg om det enskilda barnets välbefinnande, trygghet, utveckling och lärande skall prägla arbetet i</p><p>förskolan. Hänsyn skall tas till barnets olika förutsättningar och behov.” (s.4)</p><p>Det är upp till pedagogerna att anpassa den pedagogiska verksamheten så den passar alla barn.</p><p>Syftet med vårt arbete var att se hur pedagogerna upplever det att ha barn med dolda handikapp i barngruppen. Vi ville även ta reda på hur det byggs upp ett bra samarbetet med föräldrarna till barn med dolda handikapp, så att de känner en trygghet att lämna över ansvaret till förskolan.</p><p>Vi har valt att använda oss av kvalitativa intervjuer med både pedagoger och föräldrar till barn med blödarsjuka och matallergi.</p><p>Vårt resultat visar på att pedagogernas förhållningssätt är viktigt. Pedagogerna framhöll alla barn lika värde. Trots detta finns det saker som gör att barnet blir utpekat i barngruppen.</p><p>Ett bra samarbete med föräldrarna kräver en öppen och rak kommunikation.</p>
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Conformational Change in the Structure of Wheat Proteins During Mixing in Hard and Soft Wheat DoughsJazaeri, Sahar 19 March 2013 (has links)
This thesis describes an investigation of the mechanistic differences of hard and soft wheat varieties in the course of dough formation. These two classes of wheat exhibit dissimilar end-use, as hard wheat flour is known for its bread making attributes, whereas soft wheat flour is suitable for cake and cookie production. This difference is related to the grain hardness, protein content and property of gluten, in addition to chemical interactions that are occurring during dough making. Covalent and hydrophobic interactions, as well as hydrogen bond formation, are the main interactions that take place during dough mixing. However, the contribution of each interaction in dough formation of hard and soft wheat is not known. One variety of hard and one variety of soft wheat flour were mixed to their optimum hydration level (500 BU), as determined by farinograph. The extent of covalent interactions of gluten proteins during dough mixing was examined by monitoring changes in the solubility of flour proteins in a 2% Sodium Dodecyl Sulfate (SDS) media. Moreover, the contribution of thiol groups to covalent bond was examined by measuring the changes in the accessible thiols throughout the mixing. Lower extractability of proteins and accessible thiols of hard wheat
dough, compared to soft wheat dough, indicated the predominant role of covalent interactions in hard wheat dough. The complementary results from Size Exclusion High Performance Liquid Chromatography (SE-HPLC) indicated that covalent interaction of hard wheat dough primarily occurs between Low Molecular Weight (LMW) and High Molecular Weight (HMW) gluten proteins, whereas this interaction mainly occurs among LMW proteins in soft wheat doughs.
Fewer hydrophobic interactions in hard wheat dough in compare with soft wheat measured by Front-face fluorescence spectroscopy indicated that this interaction is more dominant in soft wheat dough.
Study of the conformational change in secondary structure of protein (indirect approach to monitor hydrogen bond) by fourier transform infrared (FTIR) spectroscopy showed that β-sheets are formed in both varieties at their optimum dough strength. In hard wheat dough this structure resulted mainly from disulfide linkages, whereas in soft wheat dough this structure is more likely the result of hydrophobic interactions.
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Les protéines de blé d'hiver : nouveaux agents cryoprotecteurs pour les hépatocytes de ratGrondin, Mélanie January 2008 (has links) (PDF)
Plusieurs domaines de recherche, tels que la toxicologie, la pharmacologie, la recherche et développement de nouveaux médicaments et la médecine, exige l'utilisation d'une grande quantité d'hépatocytes. Les hépatocytes de rats sont un modèle physiologique important pour étudier in vitro les composés au niveau de leur hépatotoxicité, l'induction des enzymes du métabolisme telles que les isoformes du cytochrome P450 et leurs interactions médicamenteuses, ainsi que pour établir la pertinence du modèle par rapport à l'homme. La cryoconservation permet de préserver une grande quantité d'hépatocytes fonctionnels. Cependant, les hépatocytes sont des cellules extrêmement sensibles aux dommages induits par le gel et le dégel, même après l'addition des cryoprotectants classiques tel que le DMSO. La cryoconservation réduit la viabilité et certaines fonctions hépatospécifiques. Le changement le plus prononcé est la diminution de leur efficacité d'attachement. L'adhésion des cellules à la matrice extracellulaire et les contacts cellules-cellules sont cruciaux pour plusieurs fonctions cellulaires. Ces processus sont en partie régulés par les molécules d'adhésion cellulaire. Les mécanismes responsables de la réduction de l'efficacité d'attachement des hépatocytes cryoconservés ne sont pas bien élucidés. Ainsi, l'amélioration des techniques de cryoconservation est nécessaire afin d'améliorer les fonctions et de réduire les dommages cellulaires. Dans cette thèse, nous décrivons une nouvelle méthode efficace pour la cryoconservation de cellules de mammifères basée sur l'utilisation d'un extrait de protéines de blé (WPE) ou d'un extrait partiellement purifié avec le sulfate d'ammonium ou l'acétone (SuIWPE ou AcWPE) ou de protéines recombinantes associées à la tolérance au gel chez le blé. Ces méthodes permettent l'entreposage à long terme et la récupération d'une grande quantité de cellules viables et dont les fonctions sont maintenues. Pour tester l'efficacité de cette nouvelle méthode, nous avons mesuré plusieurs paramètres, tels que la viabilité immédiatement après dégel, la viabilité en culture, l'efficacité d'adhésion et l'évaluation des fonctions hépatospécifiques (sécrétion d'albumine, biotransformation de l'ammonium en urée, activité basale et inductibilité du cytochrome P450). En culture, la morphologie des hépatocytes cryoconservés avec l'extrait de protéines de blé (WPE), l'extrait partiellement purifié (SuIWPE ou AcWPE) et les protéines recombinantes associées à la tolérance au gel chez le blé (WCS120, WSC19, WCOR410, TaTIL et TaIRl-2), est semblable à celle des cellules fraîches. De plus, la stabilité des trois principales molécules d'adhésion, soit l'intégrine β1, la E-cadhérine et la β-caténine fut étudiée. L'expression des molécules d'adhésion est généralement inférieure chez les hépatocytes cryoconservés avec le diméthylsulfoxyde (DMSO), comparativement au WPE. L'intégrine β1 et la β-caténine sont les plus touchées par la cryoconservation. Les molécules d'adhésion sont préservées chez les hépatocytes cryoconservés avec les SuIWPE, AcWPE ou les protéines recombinantes; l'expression étant faiblement diminuée comparativement aux hépatocytes frais. Par le fait même, l'adhérence cellulaire des cellules cryopréservées avec les SuIWPE, AcWPE ou les protéines recombinantes est supérieure (70%) à celle des cellules cryopréservées avec le WPE ou le DMSO (50%).
Les fonctions hépatospécifiques telles que la sécrétion d'albumine et la biotransformation de l'ammonium en urée sont maintenues durant 4 jours de culture, pour les cellules cryoconservées aves les WPEs. Nous avons également déterminé que les WPE, SuIWPE, AcWPE ou les protéines recombinantes peuvent améliorer les activités des principaux isoformes du cytochrome P450, chez les hépatocytes en suspension et en culture après cryoconservation. Ceci a été réalisé en comparant les activités basales et inductibles des isoformes CYP1A1/2, 2C6, 2D2 et 3A1/2 dans les hépatocytes de rat cryoconservés avec les WPE, SulWPE, AcWPE ou les protéines recombinantes comparativement aux cellules fraîches et les cellules cryoconservées au DMSO. Nous démontrons d'une manière concluante que les hépatocytes de rat cryoconservés avec les WPE, SuIWPE, AcWPE ou les protéines recombinantes maintiennent le même niveau de compétence métabolique et de capacité à répondre aux inducteurs classiques du CYP, que les hépatocytes fraîchement isolés. Ces résultats démontrent clairement que le WPE, et plus particulièrement, les SuIWPE, AcWPE et les protéines recombinantes, sont plus efficaces que la technique classique de cryoconservation au DMSO pour les hépatocytes de rat, tant pour le maintien de l'expression des molécules d'adhésion que pour leurs fonctions hépatospécifiques. Les extraits WPE, SuIWPE, AcWPE et protéines recombinantes contiennent des agents cryoprotecteurs potentiellement universels pour les cellules de mammifères, tout en étant économiques et non-toxiques. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Foie, Hépatocytes, Cryoconservation, Protéines de blé, Viabilité, Activité métabolique, Cyrochrome p450, Molécules d'adhésion.
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Pigment reduction in corn gluten meal and its effects on muscle pigmentation of rainbow trout (Oncorhynchus mykiss)Saez, Patricio J 10 May 2013 (has links)
Corn gluten meal (CGM) is a high protein (60% crude protein), highly digestible feed ingredient widely used in diets for salmonids, however its use has been related to reduction in muscle pigmentation possibly due to pigment interaction. Therefore, laboratory scale and in vivo trials were conducted to reduce pigment level in CGM and to assess its effect on fish muscle pigmentation, respectively. In the first chapter, a bench-scale study was carried out to investigate factors that affect bleaching of carotenoids in CGM, using white soy flake flour (WSFF) as a lipoxygenase (LOX) source. Plackett-Burman and Box-Behnken designs were used to screen and optimize factors, respectively. Furthermore, a 12-week growth trial was conducted in order to assess the effects of dietary regular and pigment bleached CGM on growth and muscle pigmentation of rainbow. In the second chapter, a 24-week growth trial was carried out in order to assess the effects of increasing levels of CGM on growth and muscle pigment deposition in rainbow trout. In the third chapter, a bench-scale (10 g) corn wet milling procedure was used to assess the bleaching of carotenoids from CGM during steeping. Studies from this thesis confirmed the negative effects of CGM on fillet pigmentation and highlighted the need for evaluation of muscle quality traits such as colour in response to inclusion of new feed ingredients. Furthermore, this thesis gives insight on how to reduce pigments from corn gluten meal using cost-effective and practical bleaching approaches.
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Development of a gluten-free commercial breadRakkar, Pardeep Singh January 2007 (has links)
Because of coeliac disease, some individuals cannot tolerate the protein gliadin present in the gluten fraction of wheat flour. From a commercial perspective, there is a need for the development of gluten-free bread with texture and flavour properties similar to the conventional wheat flour loaf. In the context of bread, the gluten component of wheat has a crucial role in stabilising the gas-cell structure and maintaining the rheological properties of the bread. The absence of gluten results in liquid batter rather than pre-baking dough, yielding baked bread with a crumbling texture, poor colour and other post-baking quality defects. The liquid batter cannot be processed on the existing production line of baking industry. The aim is to develop a gluten-free white loaf with similar quality characteristics to that of standard white bread on the existing processing lines at Quality Bakers New Zealand. Within this constraint, dough has to be produced with handling and moulding properties similar to those of conventional wheat flour loaves. This research focused on finding and implementing the gluten substitutes for the development of gluten-free high quality commercial bread. In this research, the independent variables were conventional wheat flour (the most basic control), other gluten-free flours from a variety of sources, starches, supplementary proteins, hydrocolloids such as hydroxypropylmethylcellulose (HPMC), hydrophilic psyllium husk, and enzymes such as microbial transglutaminase, glucose oxidase, lipase and fungal α-amylase. These ingredients were trialled in different combination and composition to produce a dough having ability to trap the carbon dioxide gas during proofing and baking to get high specific volume bread suitable for the Quality Bakers’ product range. After an essentially ‘shotgun’ approach to formulations, the research narrowed to a systematic and progressive variation of ingredients and their composition to develop workable commercial models. Ingredients and their compositions were manipulated according to the outcomes of the trials and their contribution in the formulations. The dependent variables included standard bakery rheological properties based on dough stickiness, dough extensibility, oven spring, bread specific volume, bread slice ability, and bread staling. A gelation system of the lower-temperature-stable hydrocolloid psyllium husk, the heat-stable hydrocolloid hydroxypropylmethylcellulose, maize starch, and potato starch was created to form industrial process able dough having ability to entrap carbon dioxide gas produced during proofing and initial phase of baking. Microbial transglutaminase was used to increase the cross linking of protein present in flours and supplemented for enhancing the dough-like structure and its gas entrapping abilities. A formulation has been discovered by this research for the development of high quality gluten-free commercial bread. The formulated bread has similar quality characteristics to that of standard white bread and can be produced on existing processing lines at Quality Bakers. Industrial process able gluten-free bread with similar quality characteristics to that of standard white bread can be formulated by using a specific combination of soy flour, maize starch, potato starch, yoghurt powder, milk protein, HPMC (K4M), psyllium husk, microbial transglutaminase, lipase, and fungal α-amylase. The significance of this research is mainly commercial and the insights gained may extend to other bakery items that could be used by coeliacs.
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