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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.
51

Obtenção de concentrado protéico de folhas e parte aérea da mandioca (Manihot Esculenta Crantz) / Obtention of proteic concentrate of leaves and aerial part of the cassava (Manihot Esculenta Crantz).

Silva, Janaina Lima da 17 July 2007 (has links)
Made available in DSpace on 2017-05-12T14:47:15Z (GMT). No. of bitstreams: 1 Janaina Lima da Silva.pdf: 3461069 bytes, checksum: 86eccae232302ee27032f84e3721edb7 (MD5) Previous issue date: 2007-07-17 / Leaves and aerial part of the cassava are great protein, vitamins, minerals and essential amino acids sources, being these abundant and in low cost. However, this residual is still little explored. The cassava leaves use as protein source is, many times, not stimulated by the presence of anti nutritional factors what indicates the obtainment of proteic concentrates. The objective of this study was to obtain proteic concentrates from cassava leaf and aerial part (leaf, stalk and stem) through 4 extraction methods, besides to evaluate the mineral composition and functional properties of the obtained concentrates. The extraction methods used were: 1) Extraction method by isoeletric precipitation described by CEREDA; VILPOUX (2003); 2) Extraction Method by fermentation described by CHAVES (1987); 3) Extraction Method by fermentation described by CHAVES (1987) with fermentation time shortening described by FERRI (2006); 4) Extraction Method by fermentation described by CHAVES (1987) with pH alteration in the end of fermentation described by FERRI (2006).It was determined for each method the extraction yield, the proteic concentrate yield, the mass and protein loss. In the obtained concentrates were determined the Fe, Mn, Cu, Na, K and Zn levels, besides the functional properties of water and oil absorption. The factorial 2X4 experimental outline was used, being its factors the material kind (leaf and aerial part) and the protein extraction methods, with 3 repetitions, constituting 24 experimental parts. The variable analysis was also made, being its averages compared by the Tukey test in the 5% significance level. The yields obtained on the leaves were 18,31%, 14,11%,14,40% and 13,45% for methods 1, 2, 3 and 4 respectively. On the aerial parts the yields of concentrate obtained were 3,66%, 6,10%, 6,30% and 6,55% for methods 1, 2, 3 and 4 respectively. The leaves presented average extraction yield values three to four times bigger than the values presented by the aerial part, being them more adequate to get proteic concentrate from. The proteic concentrates obtained presented good quantity of nutrients like Fe, Mn, Cu, Na, K and Zn, indicating their application in the food industry, without difference between the concentrates obtained from the leaves or the aerial part. It was observed an elevated capacity of water absorption on the proteic concentrates, indicating its application in foods as meat, bread, soups and sauces. The oil absorption capacity on proteic concentrates was also high, indicating their industrial application in products preparation as sausages, dough, mayonnaise and other salad dressings increasing the good flavor retention of these products. / As folhas e parte aérea da mandioca constituem-se como fontes de proteínas, vitaminas, minerais e aminoácidos essenciais, abundantes e de baixo custo. Contudo este resíduo é ainda pouco explorado. O uso de folhas de mandioca como fonte de proteínas, muitas vezes é desestimulado pela presença de fatores antinutricionais, indicando a obtenção de concentrados protéicos. O objetivo do presente trabalho foi obter concentrados protéicos de folha e parte aérea (folha, haste e caule) de mandioca, por 4 métodos de extração e avaliar a composição mineral e propriedades funcionais dos concentrados obtidos. Os métodos de extração utilizados foram: 1) Método de extração por precipitação isoelétrica descrito por CEREDA; VILPOUX (2003); 2) Método de extração por fermentação descrito por CHAVES (1987); 3) Método de extração por fermentação descrito por CHAVES (1987), com redução no tempo de fermentação descrito por FERRI (2006); 4) Método de extração por fermentação descrito por CHAVES (1987), com alteração de pH no final da fermentação proposto por FERRI (2006). Determinou-se para cada método o rendimento de extração, o rendimento de concentrado protéico, a perda de massa e perda de proteínas. Nos concentrados obtidos determinou-se o teor de Fe, Mn, Cu, Na, K e Zn e as propriedades funcionais de absorção de água e óleo. Utilizou-se delineamento experimental do tipo fatorial 2 x 4, sendo os fatores, tipo de material (folha e parte aérea) e métodos de extração de proteínas, com 3 repetições, constituindo 24 parcelas experimentais. Realizou-se análise de variância, sendo as médias comparadas pelo teste de Tukey, ao nível de 5% de significância. Para as folhas os rendimentos de concentrado obtidos foram 18,31%, 14,11%,14,40% e 13,45% para os métodos 1, 2, 3 e 4, respectivamente. Para a parte aérea os rendimentos de concentrado obtidos foram 3,66%, 6,10%, 6,30% e 6,55% para os métodos 1, 2, 3 e 4, respectivamente. As folhas apresentaram valores médios de rendimento de extração três a quatro vezes maiores que os valores apresentados pela parte aérea, indicando serem mais adequadas para obtenção de concentrado protéico. Os concentrados protéicos obtidos apresentaram bons conteúdos de nutrientes como Fe, Mn, Cu, Na, K e Zn, indicando boa aplicação como suplemento na indústria de alimentos, não havendo diferenças entre os concentrados obtidos de folha ou de parte aérea. Foi observada elevada capacidade de absorção de água nos concentrados protéicos, indicando aplicação em alimentos como carnes, pães, sopas e molhos. A capacidade de absorção de óleo dos concentrados protéicos também foi elevada, indicando boa aplicação industrial para preparação de produtos como salsichas, massas de bolos, maionese e outros molhos para saladas, aumentando a retenção de sabor nestes produtos.
52

Properties of Multifunctional Oxide Thin Films Despostied by Ink-jet Printing

Fang, Mei January 2012 (has links)
Ink-jet printing offers an ideal answer to the emerging trends and demands of depositing at ambient temperatures picoliter droplets of oxide solutions into functional thin films and device components with a high degree of pixel precision. It is a direct single-step mask-free patterning technique that enables multi-layer and 3D patterning. This method is fast, simple, easily scalable, precise, inexpensive and cost effective compared to any of other methods available for the realization of the promise of flexible, and/or stretchable electronics of the future on virtually any type of substrate. Because low temperatures are used and no aggressive chemicals are required for ink preparation, ink-jet technique is compatible with a very broad range of functional materials like polymers, proteins and even live cells, which can be used to fabricate inorganic/organic/bio hybrids, bio-sensors and lab-on-chip architectures. After a discussion of the essentials of ink-jet technology, this thesis focuses particularly on the art of designing long term stable inks for fabricating thin films and devices especially oxide functional components for electronics, solar energy conversion, opto-electronics and spintronics. We have investigated three classes of inks: nanoparticle suspension based, surface modified nanoparticles based, and direct precursor solution based. Examples of the films produced using these inks and their functional properties are: 1) In order to obtain magnetite nanoparticles with high magnetic moment and narrow size distribution in suspensions for medical diagnostics, we have developed a rapid mixing technique and produced nanoparticles with moments close to theoretical values (APL 2011 and Nanotechnology 2012). The suspensions produced have been tailored to be stable over a long period of time. 2)In order to design photonic band gaps, suspensions of spherical SiO2 particles were produced by chemical hydrolysis (JAP 2010 and JNP 2011 - not discussed in the thesis). 3) Using suspension inks, (ZnO)1-x(TiO2)x composite films have been printed and used to fabricate dye sensitized solar cells (JMR 2012). The thickness and the composition of the films can be easily tailored in the inkjet printing process. Consequently, the solar cell performance is optimized. We find that adding Ag nanoparticles improves the ‘metal-bridge’ between the TiO2 grains while maintaining the desired porous structure in the films. The photoluminescence spectra show that adding Ag reduces the emission intensity by a factor of two. This indicates that Ag atoms act as traps to capture electrons and inhibit recombination of electron-hole pairs, which is desirable for photo-voltaic applications. 4) To obtain and study room temperature contamination free ferromagnetic spintronic materials, defect induced and Fe doped MgO and ZnO were synthesized ‘in-situ’ by precursor solution technique (preprints). It is found that the origin of magnetism in these materials (APL 2012 and MRS 2012) is intrinsic and probably due to charge transfer hole doping. 5) ITO thin films were fabricated via inkjet printing directly from liquid precursors. The films are highly transparent (transparency &gt;90% both in the visible and IR range, which is rather unique as compared to any other film growth technique) and conductive (resistivity can be ~0.03 Ω•cm). The films have nano-porous structure, which is an added bonus from ink jetting that makes such films applicable for a broad range of applications. One example is in implantable biomedical components and lab-on-chip architectures where high transparency of the well conductive ITO electrodes makes them easily compatible with the use of quantum dots and fluorescent dyes. In summary, the inkjet patterning technique is incredibly versatile and applicable for a multitude of metal and oxide deposition and patterning. Especially in the case of using acetate solutions as inks (a method demonstrated for the first time by our group), the oxide films can be prepared ‘in-situ’ by direct patterning on the substrate without any prior synthesis stages, and the fabricated films are stoichiometric, uniform and smooth. This technique will most certainly continue to be a versatile tool in industrial manufacturing processes for material deposition in the future, as well as a unique fabrication tool for tailorable functional components and devices. / <p>QC 20120907</p>
53

Architecture and Mechanisms of Energy Auto-Tuning

Götz, Sebastian, Wilke, Claas, Cech, Sebastian, Aßmann, Uwe 21 August 2013 (has links) (PDF)
Energy efficiency of IT infrastructures has been a well-discussed research topic for several decades. The resulting approaches include hardware optimizations, resource management in operating systems, network protocols, and many more. The approach the authors present in this chapter is a self-optimization technique for IT infrastructures, which takes hard- and software components as well as users of software applications into account. It is able to ensure minimal energy consumption for a user request along with a set of non-functional requirements (e.g., the refresh rate of a data extraction tool). To optimize the ratio between utility of end users and the cost in terms of energy consumption, the system needs inherent variability leading to differentiated energy profiles and mechanisms to reconfigure the system at runtime. The authors present their approach called Energy Auto-Tuning (EAT) comprised of these mechanisms and an architecture which automatically tunes the energy efficiency of IT systems.
54

Towards Energy Auto Tuning

Götz, Sebastian, Wilke, Claas, Schmidt, Matthias, Cech, Sebastian, Aßmann, Uwe 21 August 2013 (has links) (PDF)
Energy efficiency is gaining more and more importance, since well-known ecological reasons lead to rising energy costs. In consequence, energy consumption is now also an important economical criterion. Energy consumption of single hardware resources has been thoroughly optimized for years. Now software becomes the major target of energy optimization. In this paper we introduce an approach called energy auto tuning(EAT), which optimizes energy efficiency of software systems running on multiple resources. The optimization of more than one resource leads to higher energy savings, because communication costs can be taken into account. E.g., if two components run on the same resource, the communication costs are likely to be less, compared to be running on different resources. The best results can be achieved in heterogeneous environments as different resource characteristics enlarge the synergy effects gainable by our optimization technique. EAT software systems derive all possible distributions of themselves on a given set of hardware resources and reconfigure themselves to achieve the lowest energy consumption possible at any time. In this paper we describe our software architecture to implement EAT.
55

Einfluss von Eingabedaten auf nicht-funktionale Eigenschaften in Software-Produktlinien

Lillack, Max 13 December 2012 (has links) (PDF)
Nicht-funktionale Eigenschaften geben Aussagen über Qualitätsaspekte einer Software. Mit einer Software-Produktlinie (SPL) wird eine Menge von verwandten Software-Produkten beschrieben, die auf Basis gemeinsam genutzter Bausteine und Architekturen entwickelt werden, um die Anforderungen unterschiedlicher Kundengruppen zu erfüllen. Hierbei werden gezielt Software-Bestandteile wiederverwendet, um Software effizienter zu entwickeln. In dieser Arbeit wird der Einfluss von Eingabedaten auf die nicht-funktionalen Eigenschaften von SPL untersucht. Es wird auf Basis von Messungen ausgewählter nicht-funktionaler Eigenschaften einzelner Software-Produkte ein Vorhersagemodell für beliebige Software-Produkte der SPL erstellt. Das Vorhersagemodell kann genutzt werden, um den Konfigurationsprozess zu unterstützen. Das Verfahren wird anhand einer SPL von verlustfreien Kompressionsalgorithmen evaluiert. Die Berücksichtigung von Eingabedaten kann die Vorhersage von nicht-funktionalen Eigenschaften einer SPL gegenüber einfacheren Vorhersagemodellen ohne die Berücksichtigung von Eingabedaten signifikant verbessern.
56

Systematische Prozessunterstützung für die Entwicklung laufzeitkritischer Softwaresysteme / PROKRIS-Methodik und -Framework

Röttger, Simone 02 December 2009 (has links) (PDF)
In vielen Bereichen des täglichen Lebens, angefangen vom Online-Banking bis hin zur Steuerung im Flugzeug, kommt Software mit laufzeitkritischen nicht-funktionalen Eigenschaften (NFE) zum Einsatz. Die Erfüllung der NFE spielt in diesen Anwendungen eine zentrale Rolle. Um dies zu erreichen, ist eine systematische und zielorientierte Behandlung dieser Anforderungen während der Entwicklung zwingend erforderlich. NFE zeichnen sich im Gegensatz zu funktionalen Eigenschaften durch besondere Merkmale aus, die ein adaptives Vorgehen zur Definition des Entwicklungsprozesses erzwingen. In der Arbeit wird eine Methodik zur kontextbasierten Anpassung von Vorgehensmodellen an laufzeitkritische NFE auf der Basis von Prozessmustern sowie das PROKRIS-Framework als unterstützende Umgebung vorgestellt.
57

Structural and functional characterization of red kidney bean (Phaseolus vulgaris) proteins and enzymatic protein hydrolysates

Mundi, Sule 09 August 2012 (has links)
Kidney bean proteins and peptides can be developed to serve as an important ingredient for the formulation of high quality foods or therapeutic products that may positively impact on body function and human health. The main goal of this thesis was to determine the in vitro structural and functional characteristics of major proteins and enzymatic protein hydrolysate of red kidney bean (Phaseolus vulgaris). Selective aammonium sulfate precipitation of the kidney bean proteins yielded 88% globulin and 7% albumin.The globulin and albumin are glycoproteins that contained ~4% and 45% carbohydrate contents, respectively. Physicochemical and functional characteristics of the globulin fraction, such as, gelation concentration, foam stability, emulsion capacity, and emulsion stability were superior to those of albumin. Reducing SDS-PAGE revealed vicilin with molecular weight of ~45 kDa as the major globulin in kidney beans. Circular dichroism spectroscopy of the purified vicilin showed reductions in α-helix, and β-pleated sheet conformations upon addition of NaCl or changes in pH. Likewise, the tertiary structures as observed from the near-UV CD spectra were also changed by shifts in pH conditions and NaCl addition. Far UV-CD showed increased β-sheet content up till 60oC from room temperature, but a steady loss in the tertiary structure as temperature was further increased; however, β-sheet structure was still detectable at 80oC. Differential scanning calorimetry thermograms showed a prominent endothermic peak with denaturation temperature at around 90oC, attributed to thermal denaturation of vicilin. Alcalase hydrolysis of kidney bean globulin produced multifunctional peptides that showed potential antihypertensive properties because of the in vitro inhibition of activities of renin and angiotensin I converting enzyme as well as the antioxidant properties. The <1 and 5-10 kDa peptide fractions exhibited highest (p<0.05) renin inhibition and the ability to scavenge 2, 2-Diphenyl-1-picrylhydrazyl free radical, inhibit peroxidation of linoleic acid and reduce Fe3+ to Fe2+. Based on this study, incorporation of kidney bean globulin as an ingredient may be useful for the manufacture of high quality food products. Likewise, the kidney bean protein hydrolysates, especially the <1 kDa fraction represent a potential source of bioactive peptides for the formulation of functional foods and nutraceuticals.
58

Structural and functional characterization of red kidney bean (Phaseolus vulgaris) proteins and enzymatic protein hydrolysates

Mundi, Sule 09 August 2012 (has links)
Kidney bean proteins and peptides can be developed to serve as an important ingredient for the formulation of high quality foods or therapeutic products that may positively impact on body function and human health. The main goal of this thesis was to determine the in vitro structural and functional characteristics of major proteins and enzymatic protein hydrolysate of red kidney bean (Phaseolus vulgaris). Selective aammonium sulfate precipitation of the kidney bean proteins yielded 88% globulin and 7% albumin.The globulin and albumin are glycoproteins that contained ~4% and 45% carbohydrate contents, respectively. Physicochemical and functional characteristics of the globulin fraction, such as, gelation concentration, foam stability, emulsion capacity, and emulsion stability were superior to those of albumin. Reducing SDS-PAGE revealed vicilin with molecular weight of ~45 kDa as the major globulin in kidney beans. Circular dichroism spectroscopy of the purified vicilin showed reductions in α-helix, and β-pleated sheet conformations upon addition of NaCl or changes in pH. Likewise, the tertiary structures as observed from the near-UV CD spectra were also changed by shifts in pH conditions and NaCl addition. Far UV-CD showed increased β-sheet content up till 60oC from room temperature, but a steady loss in the tertiary structure as temperature was further increased; however, β-sheet structure was still detectable at 80oC. Differential scanning calorimetry thermograms showed a prominent endothermic peak with denaturation temperature at around 90oC, attributed to thermal denaturation of vicilin. Alcalase hydrolysis of kidney bean globulin produced multifunctional peptides that showed potential antihypertensive properties because of the in vitro inhibition of activities of renin and angiotensin I converting enzyme as well as the antioxidant properties. The <1 and 5-10 kDa peptide fractions exhibited highest (p<0.05) renin inhibition and the ability to scavenge 2, 2-Diphenyl-1-picrylhydrazyl free radical, inhibit peroxidation of linoleic acid and reduce Fe3+ to Fe2+. Based on this study, incorporation of kidney bean globulin as an ingredient may be useful for the manufacture of high quality food products. Likewise, the kidney bean protein hydrolysates, especially the <1 kDa fraction represent a potential source of bioactive peptides for the formulation of functional foods and nutraceuticals.
59

Caracterização e modificações químicas da proteína da microalga spirulina (Spirulina máxima) / Microalgae; Proteins; Functional properties; Chemical modifications;

Carvajal, Juan Carlos Letelier 14 August 2009 (has links)
Made available in DSpace on 2015-04-17T14:49:12Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1503208 bytes, checksum: b782febd7d14045e41ee0edccb77000e (MD5) Previous issue date: 2009-08-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Maximum Spirulina is an unicellular microalga, that she has form of helical filament and that she grows in waters strongly alkaline; she belongs to the cianobacterial group, cianofíceas or algae green-blued and they have been used since times many old. The microalgae presented a biomass growth in summer of 1,07 g/L and a 23,63% of rental. Present a high contend of proteins (54.93%) and low oils content (6,84%) and ashes (13,05%), this content of proteins rises in the flour degreased for 61,14%. being Fractioned the proteins was obtained majority incomes of albumins (36,61%), basic glutelina (31,29%) and globulin (21,03%), and minority of prolaminas (3,95%) and acid glutelina (0,29%). In the obtaining of the isolated proteic, the index in extracted total protein in the three extractions was 54,36%, the index of precipitation isoelectric in the extract of pH 10,0 was 46,81% and the index of total protein in the isolated proteic was of 95,44% in pH 10,0. the analysis of the molecular weight of the proteins of the flour in PAGE-SDS - she revealed from 8 to 13 bands. The subunidades of 16,21 and 15,74 kDa appeared prominent in the sample. The term-stability (Td, ºC) and the variation entálpica (H, KCal/g), examined by DSC, respective the degreased flour and isolated proteic were of 104,58°C and 102,47°C and 0,65 Kcal.g-1 and 0,59 Kcal.g-1, respectively. The nutritional characterization of the protein of maximum Spirulina, they demonstrated a content of tannins of 17,5 mg.g-1 and absence of the lectina inhibitors and tripsina. The composition of amino acids revealed her witnesses of all of the essential amino acids in superior amounts to the pattern FAO/WHO/UNU, with predominance of the leucina (3,96g/100g protein), fenilalanina (2,92 g/100g proteins) and valina (2,71 g/100 g proteins). The results of the chemical modifications revealed that the acetilation was shown more it executes than the succinylation in the different modification degrees (1; 2.5; 5; 10 and 15%). the solubility of the isolated not modified indicated a point isoelectric (low solubility) in pH 5,0, for the isolated ones modified the point isoelectric was observed in the pH 4,0. the solubility increased with the chemical modification, being observed a larger increase in the succinylation. The capacity of absorption of water was influenced positively with the chemical modification, being observed a larger increase in the acetilation in relation to succinylation. In the same way the capacity of oil absorption increases with the modification, being observed a larger increase of the capacity in the acetilation. The emulsion capacity increased with the chemical modification in all of the modification degrees, being observed a light increase in the succinylation. The emulsion activity was increased with the chemical modification, being observed a light increase in the succinylation. The stability of the emulsion increased with the chemical modification, being observed a larger increase in the succinylation. The relative viscosity of the isolated modified proteic increased with the concentration of the protein solution, with to room temperature and with the heating (90ºC), in the measure that increases the modification degree, it also increases the viscosity. The floaming capacity increased with the chemical modification, being observed a larger index in the succinylation, in the espumação stability is noticed that the decrease in the stability was less accentuated in the acetilation than in the succinylation, in all of the analyzed times and all of the modification degrees tested. The protein of maximum Spirulina presented a chemical and nutritional characteristic satisfactory in relation to minimum demands established by the international organisms. / A Spirulina maxima é uma microalga unicelular, que tem forma de filamento helicoidal e que se desenvolve em águas fortemente alcalinas; pertence ao grupo de cianobactérias, cianofíceas ou algas verde-azulada e têm sido utilizados desde tempos muitos antigos. A microalga apresentou um crescimento de biomassa durante o verão de 1,07 g/L e um 23,63% de rendimento. Apresenta um elevado teor de proteinas (54.93%) e baixo conteúdo de lipídeos (6,84%) e cinzas (13,05 %). Este conteúdo de proteinas elevou-se na farinha desengordurada para 61,14%. Fracionando-se as proteinas obteve-se rendimentos majoritários de albuminas (36,61%), glutelina básica (31,29%) e globulina (21,03%), e minoritário de prolaminas (3,95%) e glutelina ácida (0,29%). Na obtenção do isolado protéico, o índice em proteina total extraída nas três extrações foi 54,36%, o índice de precipitação isoelétrica no extrato de pH 10,0 foi 46,81% e o índice de proteina total no isolado protéico foi de 95,44% em pH 10,0. A análise do peso molecular das proteinas da farinha em PAGE-SDS-bMe revelou de 8 a 13 bandas. As subunidades de 16,21 e 15,74 kDa apareceram proeminentes na amostra. A termoestabilidade (Td, ºC) e a variação entálpica (DH, Kcal por g), examinadas por DSC, respectivas a farinha desengordurada e isolado protéico foram de 104,58°C e 102,47°C, 0,65 Kcal.g-1 e 0,59 Kcal.g-1, respectivamente. A caracterização nutricional da proteina da Spirulina máxima, demonstrou um conteúdo de taninos de 17,5 mg.g-1 e ausência dos inibidores de lectina e tripsina. A composição de aminoácidos revelou a presencia de todos os aminoácidos essenciais em quantidades superiores ao padrão FAO/WHO/UNU, com predominância da leucina (3,96g por 100g proteina), fenilalanina (2,92 g por 100g proteinas) e valina (2,71 g por 100 g proteinas). Os resultados das modificações químicas revelaram que a acetilação se mostrou mais efetiva que a succinilação nos diferentes graus de modificação (1; 2.5; 5; 10 e 15 %). A solubilidade do isolado não modificado indicou um ponto isoelétrico (mínima solubilidade) em pH 5,0, para os isolados modificados o ponto isoelétrico se observou no pH 4,0. A solubilidade aumentou com a modificação química, detectando-se um maior aumento na succinilação. A capacidade de absorção de água foi influenciada positivamente com a modificação química, observando-se um maior aumento na acetilação em relação a succinilação. Da mesma forma a capacidade de absorção de óleo aumentou com a modificação, observando-se um maior aumento da capacidade na acetilação. A capacidade de emulsão aumentou com a modificação química em todos os graus de modificação, detectando-se um leve aumento na succinilação. A atividade de emulsão foi aumentada com a modificação química, observando-se um leve aumento na succinilação. A estabilidade da emulsão aumentou com a modificação química, detectando-se um maior aumento na succinilação. A viscosidade relativa dos isolados protéicos modificados aumentou com a concentração da solução de proteina, com a temperatura ambiente e com o aquecimento (90ºC), na medida que aumenta o grau de modificação, também aumenta a viscosidade. A capacidade de espumação aumentou com a modificação química, observando-se um maior índice na succinilação, na estabilidade de espumação percebe-se que o decréscimo na estabilidade foi menos acentuado na acetilação do que na succinilação, em todos os tempos analisados e todos os graus de modificação testados. A proteina da Spirulina máxima apresentou uma característica química e nutricional satisfatória em relação a exigências mínimas estabelecidas pelos organismos internacionais.
60

Amido modificado de taro (Colocasia esculenta L. Schott): propriedades funcionais

Almeida, Elisândra Costa 20 April 2012 (has links)
Made available in DSpace on 2015-04-17T14:49:19Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4404074 bytes, checksum: bc4a80ff3b57b8ed93458aea5420ef33 (MD5) Previous issue date: 2012-04-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Taro has economic and industrial potential to justify investment in this culture because it is a food with excellent nutritional quality, especially starch, important source of energy, frequently used in the food industry, particularly as gelling and thickening agent, applied in the development of several products. However the starch in its native form has limitations for use, requiring modifications to improve its functional properties and increasing its possibilities for use in the food industry. The objective of this research was to study and compare the properties of native starch extract from taro (Colocasia esculenta L. Schott) clone Macaquinho with its modified starch by oxidation, acid hydrolysis, succinylation, intercross and combination of hydrolysis, succinylation and intercross for use in the food industry. After extraction of the starch, it was modified by oxidation using sodium hypochlorite, hydrolysis with hydrochloric acid, succinylation with succinic anhydride and intercrossing with trimetaphosphate and sodium tripolyphosphate. According to the experiments, it was verified that the native starch extracted from Macaquinho clone contains considerable percentage of starch, low amount of substances contaminants, like proteins or lipids, without influences on the functional properties. After the modifications and combinations occurred in the native starch, they did not showed degree of substitution beyond that permitted by regulatory agencies, being in accordance with Brazilian law. The addition of the substituent groups was decisive in the characterization of the functional properties of taro starch, modified and combined. Microscopy revealed that the starch granules presented circular and polyhedral shapes. The hydrolyzed, succinylated and intercrossed starches suffered major visible alterations in their morphology due to the modifications conducted. The swelling of the granules occurred above 75oC, with prominence for the native, oxidized, succinylated and intercrossed starches, which had their swelling power increased with the increase of temperature. The highest solubility was observed in hydrolyzed starches. The higher water absorption capacity was verified in intercrossed starch and the hydrolyzed starches demonstrated higher oil absorption and paste clarity. The best paste properties were obtained to the oxidized starch, followed by native and succinylated starches, with maximum viscosity at low temperatures. However, the oxidized starch showed higher retrogradation tendency, differently from hydrolyzed starches, more stables. The functional profiles noted in native, modified and combined starches of taro were variables, which provide a lot of possibilities for their use in the food industry. / O taro apresenta potencialidades econômicas e industriais que justificam investimentos nesta cultura, pois se trata de um alimento com excelente qualidade nutricional, especialmente em amido, importante fonte energética, muito utilizado na indústria de alimentos, especialmente como agente espessante e gelificante, aplicado no desenvolvimento de inúmeros produtos. Porém o amido na sua forma nativa apresenta limitações de uso, sendo necessária sua modificação, visando a melhoria das suas propriedades funcionais e aumentando as possibilidades de utilização na indústria alimentícia. O objetivo desta pesquisa foi estudar e comparar as propriedades do amido nativo de taro (Colocasia esculenta L. Schott) clone Macaquinho com o seu amido modificado por oxidação, hidrólise ácida, succinilação, intercruzamento, e por combinação da hidrólise com succinilação e intercruzamento para utilização na indústria alimentícia. Após a extração do amido, este foi modificado por oxidação utilizando o hipoclorito de sódio, hidrólise com ácido clorídrico, succinilação com anidrido succínico e intercruzamento com trimetafosfato e tripolifosfato de sódio. Com base nos experimentos realizados constatou-se que o extrato amiláceo nativo do clone Macaquinho contém considerável percentual de amido, com baixo teor de substâncias consideradas contaminantes, não influenciando nas suas propriedades funcionais. Após as modificações e combinações conduzidas no amido nativo, os mesmos não apresentaram grau de substituição além do permitido pelos órgãos reguladores, estando em conformidade com a legislação brasileira. A inclusão dos grupos substituintes foi determinante na caracterização das propriedades funcionais do amido de taro, modificados e combinados. A microscopia revelou que os amidos apresentavam grânulos com formatos circulares e poliédricos. Os amidos hidrolisados, succinilados e intercruzados, sofreram maiores alterações visíveis em sua morfologia, devido às modificações conduzidas. O intumescimento dos grânulos ocorreu acima de 75ºC, com destaque para os amidos nativo, oxidado, succinilado e intercruzado, que tiveram seu poder de inchamento aumentado com a elevação da temperatura. Os maiores perfis de solubilidade foram constatados nos amidos hidrolisados. A maior capacidade de absorção de água foi observada nos amidos intercruzados e a absorção de óleo foi mais evidenciada nos amidos hidrolisados, que também apresentaram maior claridade da pasta. As melhores propriedades de pasta foram obtidas no amido oxidado, seguido dos amidos nativo e succinilado, com viscosidades máximas em temperaturas mais baixas. Porém o amido oxidado apresentou maior tendência à retrogradação, diferentemente dos amidos hidrolisados com pastas mais estáveis. Os perfis funcionais constatados nos amidos nativo, modificados e combinados de taro foram variáveis, o que propicia uma série de possibilidades para a sua utilização na indústria alimentícia.

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