O preparo de eletrólitos sólidos poliméricos (ESPs) a partir de amidos de mandioca modificados (catiônico, eterificado e oxidado) com o objetivo de aplicação em, por exemplo, dispositivos eletrocrômicos é descrito nesse trabalho. Os materiais estudados foram obtidos a partir de amidos de mandioca modificados quimicamente (catiônico, eterificado e oxidado) plastificados com glicerol e etileno glicol e tendo como sal, o perclorato de lítio (LiClO4). Para um estudo completo foi investigada a influência do plastificante e do sal nas propriedades dos ESPs. Para o glicerol foram utilizadas concentrações em massa de 25 e 30%, e para o etileno glicol, variações de 30 a 50%. Em relação ao sal de lítio (LiClO4), as concentrações foram: 8,10,12,15,20 e 30 [O]/[Li], onde [O] é referente aos mols de oxigênio presentes no amido e plastificante (glicerol ou etileno glicol), e [Li] referente aos mols do íon Li+. A caracterização do material obtido foi feita utilizando-se as técnicas básicas de caracterização de materiais tais como: análises térmicas (DSC, TG), medidas óticas (IR), visualização da superfície das amostras através de microscopia eletrônica de varredura (MEV), ressonância magnética nuclear (RMN) e como a mais importante, medidas de condução iônica, através de espectroscopia de impedância eletroquímica (EIE), onde as amostras plastificadas com 30% de glicerol em relação à massa de amido apresentaram as melhores propriedades de condutividade, aderência e estabilidade para amostras com amido eterificado, tendo um máximo de condutividade de 3,45.10-6 S/cm para na quantidade de sal na razão 15[O]/[Li]. Em amostras contendo amido catiônico, obtiveram-se valores parecidos de condutividade quando plastificados com etileno glicol, nas razões de sal de lítio igual a 10[O]/[Li], 15[O]/[Li] e 20[O]/[Li], no entanto o melhor valor de condutividade ocorreu em filmes plastificados com 30% de etileno glicol e 08 [O]/[Li], apresentando o valor de 1,55.10-3 S/cm. Para amostras contendo amido oxidado, pode-se concluir que filmes contendo 30% de etileno glicol e sal na concentração de 8[O]/[Li] apresentam melhores resultados de condutividade iônica. Também foi observado em algumas amostras, que a condutividade em função da temperatura varia linearmente com o aumento da temperatura, mas para amostra com baixa concentração de sal, não se observa mais essa linearidade ([O]/[Li]=30). Isto significa que as espécies responsáveis pela condução estão inseridas em uma matriz que ora coopera com o deslocamento dos íons (Modelo VTF característico para amostras entrecruzadas e em concentrações altas de sal ([O]/[Li]=8) estes movimentos parecem não ter grandes influências no transporte iônico (Modelo Arrhenius); caso das amostras plastificadas. / Natural polymers are very interesting matrix to obtain solid polymeric electrolytes (SPE). The principal advantage comes from its particularly interesting biodegradation properties due to the natural precedence and also very low cost and good physical and chemical properties. These polymers contain heteroatoms in its structure and for this reason can complex protons or lithium ions leading to the ionic conduction. Among different natural polymers, starch-based SPEs show good opto-electrochemical characteristics and can be applied in electrochemical devices. This work presents the results of cassava starch derivatives-based electrolytes, which were characterized by impedance spectroscopy (EIE), thermal analysis (TGA and DSC) and scanning microscopy (SEM).. The SPEs samples were obtained from cationic, eterified and oxidated starches plasticized with glycerol and ethylene glycol and containing lithium salt LiClO4. Different compositions of SPEs i.e. salt and plasticizer quantities were investigated, where it was observed that the ionic conductivity results obtained for these SPEs varied from 10-9 S/cm to 10-4 S/cm at room temperature depending on the sample and increased following Arrhenius or VTF ionic conductivity models. The best results of ionic conductivity values of 1,55.10-3 S/cm were obtained for SPEs oxidized starch plasticized with 30% of ethylene glycol and containing 08 [O]/[Li]. Thermal analysis using thermogravimetry (TGA) was performed in order to observe the change in degradation temperature caused by the changes performed on the samples. Good conductivity results combined with transparency and good adhesion to the electrodes have shown that starch-based SPEs are very promising materials to be used as solid electrolytes in electrochromic devices.

The papermaking industry uses a large amount of starch each year, both as a wet-end additive and as a rheological modifier in surface sizing and coating colors. It is important to be able to reduce the amount of chemicals used in the papermaking and surface treatment process, to reduce costs and to make the process even more efficient. Interest in new high-performance starches is great. By using these new types of starches, improved recycling of barrier products may be obtained as well as a reduction in the use of synthetic sizing agents. The objectives of this work were to understand the behavior of temperature-responsive hydrophobically modified starches, where the solubility in water simply can be adjusted by temperature or by polymer charge, to improve the barrier properties, like the water vapor permeability, mechanical properties and water resistance (Cobb and contact angle) of papers surface sized by starch-containing solutions, and to investigate the potential for industrial use of these temperature-responsive starches. It was demonstrated that the temperature-responsive starches phase separate upon cooling and, depending on the charge density of the starch, a particulate precipitation or a gel-like structure was obtained. The starch with zero net charge showed a larger increase in turbidity than the starch with a cationic net charge, indicating that particulate precipitation is favored by a zero net charge and that the formation of a gel network is favored by charged starch molecules. Further, the starches formed inclusion complexes with surfactants, giving stabilization to the starches in the presence of surfactants. The net charge density of the starch and the charge of the surfactant determined whether or not an inclusion complex would form between them. Important mechanisms for the stability of the starch seemed to be formation of mixed micellar-like structures between the hydrophobic chain of the starch and the surfactant along the starch backbone in addition to formation of inclusion complexes between the starch and the surfactant. The hydrophobically modified starches showed higher hydrophobic surface character when applied to the paper surface above the critical phase separation temperature than with application at room temperature. Free films of the temperature-responsive starches showed good barrier against oxygen, but no barrier against water vapor. The mechanical properties decreased with addition of glycerol to the films.

The main objective of the study was to evaluate the effects of starch and gum types on product quality of deep-fat fried carrot slices. It was also aimed to evaluate the applicability of image processing for determination of oil uptake. In the first part of the study, carrot slices were dipped into batters containing three different concentrations of dextrin or pre-gelatinized tapioca starch and fried for 2, 3, and 4 minutes at 170&plusmn / 2 oC. Coating pick-up of batter formulations and moisture content, oil content, frying yield, bulk density, porosity, texture and color of fried slices were evaluated. In the second part of the study, the effects of different gum types (HPMC, xanthan gum, guar gum, guar-xanthan gum combination) on quality attributes were studied. No starch or gum added coating formulation was used as the control. Finally, images of carrot and batter sections of the fried samples were obtained using digital camera and area fractions of oil droplets were determined using image processing. Acceptable product quality was obtained at higher concentrations of pre-gelatinized tapioca starch. On the other hand, increasing dextrin concentrations had an adverse affect on the product quality. As a result of the study, guar-xanthan gum combination has been found as the most effective additive on the batter performance. This additive provided the highest moisture content, lowest oil content, highest volume and lightest color to the product after frying. The porous and crunchy structure obtained using this combination was at the acceptable level for deep-fat fried products. Determination of area fraction of oil droplets on carrot and batter surfaces of fried samples using image processing was correlated with the oil content of fried product at initial stages of frying. The correlation coefficient between moisture content and frying yield was found as 0.90. A correlation was also determined between oil content and moisture content (r= -0.88).

Starch is an attractive raw material for biodegradable plastic applications due to its low cost, its availability in large quantities and its excellent thermal process-ability using conventional plastic processing equipments. Despite its attractive potential as a biopolymer material, the use of starch in biodegradable plastic applications is yet limited by its structural and functional properties, which are dictated by its genetic make up. This dissertation involves in-depth characterisations of a range of biotechnologically derived novel starches from different cereal sources to elucidate the relationship between starch structure and functionality. The importance of understanding starch structure-functionality relationship to further the development of starch biodegradable plastics are discussed to identify the research questions, which underlie the motivation of this dissertation and to contextualize the objectives of this dissertation. Diversities in starch macromolecular properties namely the amylose content and amylopectin chain length distribution are evident in these novel starches. The variation in amylopectin structure in these novel starches is explicable by considering the particular inhibition of starch biosynthesis gene expression in the generation of these starch mutants. Amylose content and amylopectin chain length distribution are two separate structural parameters in starch, which influence the granular and functional properties of starch. An improved method to analyse the 13C solid state NMR spectra for native starches was developed in this dissertation and provides the first elucidation on the occurrence of V-type polymorph, which is significant in high amylose starches. An increase in starch amylose content (or decrease in amylopectin content) leads to a decrease in the double helix content and crystallinity. A transition in the double helical packing arrangement of amylopectin side chains from A-type to B-type polymorph is noted for high amylose starches. This can be attributed to the changes in their amylopectin chain length distribution, which leads to the tendency of the glucan chains to form the B-type polymorph during crystallisation from thermodynamic considerations. The application of MTDSC provides the first elucidation on the step transition or heat capacity change, which is noted to occur within the gelatinisation endotherm for all starches. The use of Rheoscope, which allows for simultaneous monitoring of the changes in starch granular and rheological properties during gelatinisation, reveals that the manifested changes in viscosity can be attributed to the increase in the granules size as a result of swelling, the change in granules properties from rigid to more deformable granules due to water penetration and the increase in the viscosity of the continuous phase due to leaching of amylose. The variation in starch gelatinisation thermal properties namely the onset temperature, enthalpy and heat capacity change can be attributed to the variation in amylopectin chain length distribution, amylose content and the amount of starch structural order. A reduction in swelling power with increasing amylose content is consistently noted for all starch types. The variation in starch rheological responses during gelatinisation can be mainly attributed to the swelling ability of starch granules and their granule size distribution (to a lesser extent). Further MTDSC investigations on starch gelatinisation in the presence of water and glycerol with different concentrations indicate that plasticisation of starch granules prior to gelatinisation does not occur. The observed mid-temperature of the step transition (heat capacity change) is more likely due to a change in state of the starch macromolecules from being highly restrained within the granular packing to entangled macromolecules (as the order to disorder transition occurs) rather than due to glass transition. The addition of glycerol promotes starch gelatinisation in a similar way as the addition of water, which suggests that the same structural changes occur during gelatinisation regardless of the solvents used. In summary, the following starch structure-functionality relationships are deduced. The variation in starch macromolecular properties can be attributed to their corresponding mutation of starch biosynthetic genes expression. The variation in starch amylose content affects the extent of structural order inside the granules while the double helix packing arrangement is influenced by the amylopectin chain length distribution. Starch gelatinisation thermal properties are mainly influenced by the amylopectin chain length distribution while the swelling power and rheological properties are mainly affected by the amylose content.

O preparo de eletrólitos sólidos poliméricos (ESPs) a partir de amidos de mandioca modificados (catiônico, eterificado e oxidado) com o objetivo de aplicação em, por exemplo, dispositivos eletrocrômicos é descrito nesse trabalho. Os materiais estudados foram obtidos a partir de amidos de mandioca modificados quimicamente (catiônico, eterificado e oxidado) plastificados com glicerol e etileno glicol e tendo como sal, o perclorato de lítio (LiClO4). Para um estudo completo foi investigada a influência do plastificante e do sal nas propriedades dos ESPs. Para o glicerol foram utilizadas concentrações em massa de 25 e 30%, e para o etileno glicol, variações de 30 a 50%. Em relação ao sal de lítio (LiClO4), as concentrações foram: 8,10,12,15,20 e 30 [O]/[Li], onde [O] é referente aos mols de oxigênio presentes no amido e plastificante (glicerol ou etileno glicol), e [Li] referente aos mols do íon Li+. A caracterização do material obtido foi feita utilizando-se as técnicas básicas de caracterização de materiais tais como: análises térmicas (DSC, TG), medidas óticas (IR), visualização da superfície das amostras através de microscopia eletrônica de varredura (MEV), ressonância magnética nuclear (RMN) e como a mais importante, medidas de condução iônica, através de espectroscopia de impedância eletroquímica (EIE), onde as amostras plastificadas com 30% de glicerol em relação à massa de amido apresentaram as melhores propriedades de condutividade, aderência e estabilidade para amostras com amido eterificado, tendo um máximo de condutividade de 3,45.10-6 S/cm para na quantidade de sal na razão 15[O]/[Li]. Em amostras contendo amido catiônico, obtiveram-se valores parecidos de condutividade quando plastificados com etileno glicol, nas razões de sal de lítio igual a 10[O]/[Li], 15[O]/[Li] e 20[O]/[Li], no entanto o melhor valor de condutividade ocorreu em filmes plastificados com 30% de etileno glicol e 08 [O]/[Li], apresentando o valor de 1,55.10-3 S/cm. Para amostras contendo amido oxidado, pode-se concluir que filmes contendo 30% de etileno glicol e sal na concentração de 8[O]/[Li] apresentam melhores resultados de condutividade iônica. Também foi observado em algumas amostras, que a condutividade em função da temperatura varia linearmente com o aumento da temperatura, mas para amostra com baixa concentração de sal, não se observa mais essa linearidade ([O]/[Li]=30). Isto significa que as espécies responsáveis pela condução estão inseridas em uma matriz que ora coopera com o deslocamento dos íons (Modelo VTF característico para amostras entrecruzadas e em concentrações altas de sal ([O]/[Li]=8) estes movimentos parecem não ter grandes influências no transporte iônico (Modelo Arrhenius); caso das amostras plastificadas. / Natural polymers are very interesting matrix to obtain solid polymeric electrolytes (SPE). The principal advantage comes from its particularly interesting biodegradation properties due to the natural precedence and also very low cost and good physical and chemical properties. These polymers contain heteroatoms in its structure and for this reason can complex protons or lithium ions leading to the ionic conduction. Among different natural polymers, starch-based SPEs show good opto-electrochemical characteristics and can be applied in electrochemical devices. This work presents the results of cassava starch derivatives-based electrolytes, which were characterized by impedance spectroscopy (EIE), thermal analysis (TGA and DSC) and scanning microscopy (SEM).. The SPEs samples were obtained from cationic, eterified and oxidated starches plasticized with glycerol and ethylene glycol and containing lithium salt LiClO4. Different compositions of SPEs i.e. salt and plasticizer quantities were investigated, where it was observed that the ionic conductivity results obtained for these SPEs varied from 10-9 S/cm to 10-4 S/cm at room temperature depending on the sample and increased following Arrhenius or VTF ionic conductivity models. The best results of ionic conductivity values of 1,55.10-3 S/cm were obtained for SPEs oxidized starch plasticized with 30% of ethylene glycol and containing 08 [O]/[Li]. Thermal analysis using thermogravimetry (TGA) was performed in order to observe the change in degradation temperature caused by the changes performed on the samples. Good conductivity results combined with transparency and good adhesion to the electrodes have shown that starch-based SPEs are very promising materials to be used as solid electrolytes in electrochromic devices.

No description available.

Pour cette étude, dans un premier temps, une caractérisation physico-chimique et rhéologique des amidons natifs de deux cultivars locaux de pomme de terre (Sipiera et Tselefou) et de trois de manioc (2425, 4115 et Seedling) a été faite avant leur incorporation dans du pâté de bœuf à 20, 30, 40 et 50g/kg de mêlée. L’influence du type d’amidon et de leur taux d’incorporation sur les propriétés physico-chimiques et texturales des pâtés a été évaluée. Les résultats ont montré que les propriétés physiques, fonctionnelles et rhéologiques des amidons sont étroitement liées à leur origine botanique. L’Analyse en Composantes Principales (ACP) laisse paraître que de tous les amidons natifs, celui du cultivar de pomme de terre Sipiera se rapproche le plus du témoin. Une fois incorporé dans les pâtés ; l’ACP de tous les paramètres texturaux des pâtés aux amidons natifs indique que le pâté à l’amidon du cultivar de manioc Seedling à de 40g/kg de mêlée (PS40), est celui qui se rapproche le plus du pâté témoin. Dans un deuxième temps, les amidons de pomme de terre (Sipiera) et de manioc (2425) ont été sélectionnés pour la modification (acétylation). Ces amidons acétylés ont par la suite fait l’objet des mêmes analyses que les amidons natifs et incorporés dans les pâtés aux mêmes taux que les amidons natifs. Des résultats, il ressort que les propriétés fonctionnelles des amidons natifs sont fortement influencées par l’acétylation et le temps d’acétylation. Les essais d’incorporation des amidons acétylés dans les pâtés montrent que l’amidon Sipiera/20 à un taux d’incorporation de 40g/kg de mêlée ne se distingue pas significativement (p>0,05) du pâté témoin / The first part of this work deals with the physico-chemical and rheological characterisation of native starches of two local cultivars of Irish potatoes (Sipiera and Tselefou) and three cultivars of cassava (2425, 4115 and Seedling) before they are incorporated into beef patty at 20, 30, 40 and 50g/kg ground meat. The influence of the type of starch and the amount of incorporation on the physico-chemical and textural properties of patties was evaluated. Results show that the physical, functional and rheological properties of starches are closely related to their botanical origin. Principal Component Analysis (PCA) showed that Irish potato cultivar Sipiera had properties that were close to reference. The PCA of all the textural properties of patties with native starches show that patty from starch of cassava cultivar Seedling at 40g/kg (PS40) was closest to the reference. In the second part of the work, the starch Sipiera and 2425 were selected for modification. These two starches were then acetylated for 10 and 20min. and this permitted us to have Sipiera/10, Sipiera/20, 2425/10 and 2425/20. The functional properties of the native starches were however strongly influenced by acetylation and the time of acetylation. Incorporation trials of this acetylated starches at different amounts in patty showed that Sipiera/20 starch at an incorporation rate of 40g/kg ground meat is not significantly different from the reference patty

Made available in DSpace on 2017-07-21T18:53:18Z (GMT). No. of bitstreams: 1 Tiago Andre Denck Colman.pdf: 2275498 bytes, checksum: 7e32b023c4865edb06d349d33b4c809d (MD5) Previous issue date: 2013-05-07 / Samples of acid-modified and oxidised untreated cassava starch were exposed to microwave radiation for periods of five, ten and fifteen minutes. Immediately after these exposure periods the temperature of each starch sample was measured, which was at a maximum of 135 °C. All samples were analysed by thermogravimetry and derivative thermogravimetry (TG/DTG); differential scanning calorimetry (DSC); rapid viscoamylographic analysis (RVA); X-ray diffraction powder, and non-contact atomic force microscopy (NC-AFM). Colour characteristics were determined by reflectance spectrophotometry. Thermal behaviour, gelatinisation temperature, enthalpy, and paste and structural properties were determined. Viscosity gradually decreased with increasing exposure to microwaves for the samples of untreated and oxidised starch samples. The acid-modified starch failed to show pasting properties during all the periods of exposure to radiation. The relative degree of crystallinity (%) increased with the acid-modification and decreased with increasing exposure time to microwave radiation. The micro images obtained by NC-AFM showed a gradual increase in the diameter of the granules of the acid-modified and oxidised starches; for the samples of untreated starch no significant variation was observed in the granule diameter after exposure to microwaves. Reflectance spectrophotometry showed that there was a progressive change in colour due to the microwave action causing a trend mainly to yellow for all the studied samples. / Amostras de amido de mandioca nativo, ácido-modificado e oxidado foram expostas a radiação de micro-ondas pelos tempos de cinco, dez e quinze minutos. Imediatamente após a exposição, foi medida a temperatura de cada uma das amostras de amido, que foi de no máximo de 135 ºC. Todas as amostras foram analisadas por Termogravimetria e Termogravimetria Derivada (TG/DTG), Calorimetria Exploratória Diferencial (DSC), Análise Viscoamilográfica (RVA), Difração de raios X em pó, microscopia de força atômica, pelo método não-contato (NC-AFM) e as características de cor foram determinadas por espectrofotometria de refletância. O comportamento térmico, temperaturas de gelatinização, entalpia e propriedades de pasta e estruturais foram determinados. A viscosidade diminuiu gradualmente com o aumento a exposição as micro-ondas para as amostras de amido nativo e oxidado e as amostras de amido ácido-modificado deixaram de apresentar propriedades de pasta em todos os tempos de exposição a radiação. O grau de cristalinidade relativa (%) aumentou com a modificação ácida e diminuiu proporcionalmente ao aumento de tempo de exposição as micro-ondas. As microimagens obtidas através da NC-AFM revelaram um aumento gradual no diâmetro dos grânulos dos amidos ácido-modificado e oxidado e para as amostras de amido nativo não foi observada variação significativa no diâmetro dos grânulos com a exposição as micro-ondas. A espectrofotometria de reflectância demonstra que ocorreu uma alteração na cor pela ação das micro-ondas progressivamente causando principalmente a tendências para amarelo para todas as amostras estudadas.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-08-20T20:36:05Z No. of bitstreams: 1 KARLA BARBOZA PEREIRA – DISSERTAÇÃO (PPGEP) 2018.pdf: 3342395 bytes, checksum: 50f9230ad950efa47105de21f3f44c6f (MD5) / Made available in DSpace on 2018-08-20T20:36:05Z (GMT). No. of bitstreams: 1 KARLA BARBOZA PEREIRA – DISSERTAÇÃO (PPGEP) 2018.pdf: 3342395 bytes, checksum: 50f9230ad950efa47105de21f3f44c6f (MD5) Previous issue date: 2018-02 / A inserção no mercado de novos produtos isentos de glúten é fundamental para garantir a segurança alimentar dos celíacos, especialmente de massas alimentícias que representam um item básico na dieta do brasileir o; porém a eliminação total do glúten de sua composição, com suas propriedades viscoelásticas ímpares gera um desafio aos pesquisadores que precisam desenvolver um produto com características físicas e sensoriais semelhantes. Pretendeu-se com essa pesquisa desenvolver uma formulação de uma massa livre de glúten elaborada a partir de féculas de batata, fécula mandioca e farinha de arroz vermelho adicionado de goma xantana. Para tanto , foram desenvolvidas massas alimentícias com três formulações (5, 10 e 15 % de fécula de mandioca) que foram secas em seis temperaturas (40, 50, 60, 70, 80 e 90 °C). As matérias -primas básicas e suas formulações foram avaliadas quanto a sua granulometria, morfologia e calorimetria. Os modelos de Page, Cavalcanti Mata, Thompson e Fick foram utilizados para estudar a cinética de secagem das massas. As amostras foram avaliadas quanto ao teor de água, cinzas, minerais, pH, amido, lipídeos, proteínas, carboidratos totais, valor calórico total, fibras, compostos fenólicos, tempo de cozimento, aumento de volume, perda de sólidos solúveis, rendimento, fraturabilidade, dureza e atividade de água (durante armazenamento por 180 dias). Por fim, as amostras foram avaliadas microbiologicamente e sensorialmente. Neste estudo conclui-se que: as frações granulométricas presentes em maior quantitativo, foram as que ficaram retidas na peneira de 32 Mesh, com exceção da fécula de batata. Foi observada uma morfologia: homogênea e caracterizada pelo formato ovalado para as féculas; heterogênea com a presença de estruturas irregulares para a farinha de arroz e heterogênea e com predominância de estruturas ovaladas para as formulações. A fécula de mandioca causou uma antecipação no processo de gelatinização da massa alimentícia. Os modelos de Page, Cavacanti Mata se ajustaram adequadamente aos dados experimentais . Com o aumento da temperatura de secagem ocorre uma redução do tempo de secagem e a perda de água das amostras é mais intensa no início da secagem e proporcional à temperatura; o valor do coeficiente de difusão aumenta com o aumento da temperatura. Os minerais presentes em maiores quantidades foram potássio, fósforo e cálcio . Os valores de amido, proteínas, fibras (para 5% e 90 °C), tempo de cozimento, aumento de volume, rendimento e atividade de água sofreram redução com o aumento da temperatura de secagem; já os valores de cinzas, compostos fenólicos, perda de sólidos, fraturabilidade e dureza sofreram aumento com o aumento da temperatura. Os valores de cinzas ( para 40 e 80 °C), lipídeos, valor calórico, fibras (na temperatura de 90°C) e compostos fenólicos sofreram redução com o aumento do percentual de fécula de mandioca; já os valores de amido, carboidratos totais, tempo de cozimento (para 40 °C), fraturabilidade, dureza e atividade de água sofreram aumento com o aumento do percentual de fécula de mandioca. A análise microbiológica realizada indicou que a massa alimentícia foi processada em condições higiênico-sanitárias adequadas. A amostra que teve maior preferência foi a com maior percentual de fécula de mandioca em sua formulação (15 %) / The insertion in the market of new gluten-free products is fundamental to ensure the food safety of celiac, especially pasta which represent a basic item in the Brazilian diet; but the total elimination of gluten from its composition with its unique viscoe lastic properties poses a challenge to researchers who need to develop a product with similar physical and sensory characteristics. The aim of this research was to develop a formulation of a gluten-free pasta made from potato starch, manioc starch and red rice flour added with xanthan gum. For this purpose, pasta was developed with three formulations (5, 10 and 15% manioc starch) that were dried at six temperatures (40, 50, 60, 70, 80 and 90 °C). The basic raw materials and their formulations were evaluated for particle-size, morphology and calorimetry. The models of Page, Cavalcanti Mata, Thompson and Fick were used to study the drying kinetics of the masses. The samples were evaluated for water, ash, minerals, pH, starch, lipids, proteins, total carbohydrates, total caloric value, fibers, phenolic compounds, cooking time, volume increase, loss of soluble solids, yield, brittleness, hardness and water activity (during storage for 180 days). Finally, the samples were evaluated microbiologically an d sensorial. In this study, it was concluded that: the particle-size fractions present in larger quantities, were those that were retained in the 32 Mesh sieve, except for potato starch. A morphology was observed: homogeneous and characterized by the oval shape for the starches; heterogeneous with the presence of irregular structures for the rice flour and heterogeneous and with predominance of oval structures for the formulations. Manioc starch caused a antecipation in the gelatinization process of the pasta. The Page, Cavacanti Mata models fit the experimental data accordingly. As the drying temperature increases, a reduction in the drying time occurs and the water loss of the samples is more intense at the beginning of drying and proportional to the temperature; the value of the diffusion coefficient increases with increasing temperature. The minerals present in higher amounts were potassium, phosphorus and calcium. The values of starch, proteins, fibers (at 5% and 90 °C), cooking time, volume increase, yield and water activity were reduced with increasing drying temperature; already the values of ash, phenolic compounds, loss of solids, brittleness and hardness have increased with increasing temperature. The val ues of ash (for 40 and 80° C), lipids, caloric value, fibers (at 90 °C) and phenolic compounds were reduced with increasing percentage of manioc starch; the values of starch, total carbohydrates, cooking time (to 40 °C), brittleness, hardness and water activity increased with increasing percentage of manioc starch. The microbiological analysis indicated that the food was processed under adequate hygienicsanitary conditions. The sample with the highest preference was the one with the highest percentage of manioc starch in its formulation (15%).

The effects of oxidation by sodium hypochlorite (0, 0.8, 2, and 5%, NaOCl), the presence of endogenous proteins, and amylose content on waxy and common rice flours (WF, CF) and starches (WS, CS) were investigated in terms of in vitro starch digestibility, morphology and surface properties, and thermal and rheological characteristics. The concentration of NaOCl had an effect on all the samples including WF, CF, WS, and CS. The carbonyl and carboxyl group contents increased up to 25 and 10 folds (P < 0.05) of oxidized starches (WS, CS), respectively. Only mild oxidation (P < 0.05) occurred in flours (WF, WS). In addition, endogenous proteins were oxidized according to amino acid analysis and SDS–PAGE results. Glu+Gln, Gly, His, Arg, Tyr, and Lys were more sensitive to NaOCl oxidation. Disulfide bonds, hydrophobic force, and hydrogen bonds were involved in protein polymerization after NaOCl oxidative modification. In granular state, the in vitro starch digestibility of WF, WS, and CS decreased by 5% NaOCl oxidation. After gelatinization, only 2 and 5% oxidized WS had lower digestibility. Scanning electron microscopy and confocal laser scanning microscopy further demonstrated that protein existed on the surface of starch granules and had aggregation by oxidation. X-ray diffraction patterns showed the crystallinity of 5% oxidized flours and starches was reduced compared with all their non-oxidized samples. Thermal and rheological properties were analyzed by differential scanning calorimetry and rheometer, respectively. Starch gelatinization peak temperature of flours (WF, RF) was increased by 3 °C, but starches (WS, CS) had a significantly decrease by 8 °C. Viscoelastic patterns were dramatically changed by oxidation. Oxidized WF and CF had increased in both viscosity and elasticity by oxidation, whereas both WS and CS had significantly lower viscoelasticity after oxidative modification.