Secagem a vácuo de yacon : influência das condições de processo sobre parâmetros de qualidade e cinética de secagem

Orientadora: Profª. Drª. Maria Lucia MassonCo-orientador: Prof. Dr. Marcelo Kaminski LenziTese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduaçao em Tecnologia de Alimentos. Defesa: Curitiba, 18/11/2011Inclui bibliografiaResumo: O objetivo do presente trabalho foi estudar a cinética da secagem a vácuo de fatias de yacon (Smallanthus sonchifolius) e avaliar o efeito de diferentes condições de processo sobre parâmetros de qualidade do produto. O yacon é um tubérculo considerado alimento funcional devido ao seu alto teor de fibras pré-bióticas e compostos fenólicos. Para ajustar os dados de cinética da secagem a vácuo do yacon, foram utilizados os modelos de Newton, Henderson- Pabis, Page e Page modificado. A influência da temperatura de secagem, concentração de ácido cítrico no pré-tratamento de inibição enzimática e espessura das fatias sobre a cor, a textura, umidade, a atividade de água, a razão de reidratação e a dimensão fractal foi avaliada por meio de um delineamento fatorial 2 e três repetições no ponto central. As variações de cor e textura ao longo da secagem a vácuo também foram avaliadas. A estimativa de erro experimental foi realizada com base nas medidas de atividade de água do yacon processado nos experimentos conduzidos no ponto central. Os resultados mostraram que o modelo de Page modificado explicou a variação da umidade do yacon ao longo da secagem a vácuo com o mais alto valor de coeficiente de determinação e o mais baixo valor de erro médio de predição. Com o avanço da secagem, a cor do yacon tornou-se mais escura (diminuição do valor de luminosidade ou L*), mais vermelha (aumento da tonalidade verde-vermelha ou a*) e mais amarela (aumento da tonalidade azul-amarela ou b*). A textura do yacon variou pouco nos instantes iniciais de secagem, seguida de amaciamento (diminuição da dureza) em instantes intermediários e endurecimento (aumento da dureza) nos instantes finais. Observouse que altas temperaturas (58 - 65 °C), baixas espessuras (< 0,4 cm) e altas concentrações de ácido (0,8 - 1,0 g/100 g) deram origem a produtos de cor pouco escurecida (altos valores de L*), amarela dourada (altos valores de b*) e bastante apelativa (altos valores de C*). A dimensão fractal diminuiu com o aumento da temperatura de secagem. A taxa de reidratação diminuiu com o aumento da espessura das fatias. Obteve-se correlações significativas da dimensão fr ctal com a umidade final, tonalidade (h*) e razão de reidratação, sugerindo que estas análises podem ser complementadas por uma análise de imagem. Todos os ensaios deram origem a produtos com atividade de água inferior a 0,6, o que sugere que o produto final é estável ao armazenamento prolongado.Abstract: The aim of this work was to study the vacuum drying kinetics of yacon (Smallanthus sonchifolius) slices and evaluate the effect of variable process conditions on product quality parameters. Yacon is considered a functional tuber due to its high prebiotic fibers and phenolic compounds contents. In order to fit the vacuum drying kinetics of yacon, the Newton, the Henderson-Pabis, the Page and the Modified Page models were used. The influence of drying temperature, citric acid concentration in the enzymatic inhibition pretreatment e slices thickness on color, texture, water activity, rehydration ratio and fractal dimension was evaluated by using a 2 full factorial design with three replications in the center point. The changes in product color and texture during drying were also evaluated. The experimental error was evaluated on the basis of the water activity measurements of the yacon processed in the trials carried out in the center points. Results showed that the Modified Page model explained the changes in yacon moisture content during the vacuum drying with the highest value of coefficient of determination and the lowest value of mean prediction error. With the advance of the drying process, the yacon color became darker (decrease in lightness value or L*), redder (increase in greenness-redness or a*) and yellower (increase in bluenessyellowness or b*). The yacon texture changed little on initial drying stages, followed by softening (decrease in hardness) at intermediate drying times and hardening (increase in hardness) at the end of the drying process. It was observed that high temperatures (58 - 65 °C), low thicknesses (< 0.4 cm) and high acid concentrations (0.8 - 1.0 g/100 g) yielded products with slightly darkened (high L* values), golden yellow (high b* values) and very appealing (high saturation or C*) color. The fractal dimension decrease with an increase in temperature. The rehydration ratio decrease with an increase in slices thickness. Significant correlations between fractal dimension and final moisture content, hue angle (h*) and rehydration ratio were obtained, suggesting that such analyses may be complemented by and image analysis. All assays yielded products presenting water activity below 0.6, suggesting that the final product is shelf-stable

Efeito dos processos de branqueamento e acidificação sobre a cor e a absorção de gorduras de batatas-palha /

Orientadora : Nina WaszczynskyCo-orientadora : Maria Lucia MassonDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduaçao em Tecnologia de Alimentos. Defesa: Curitiba, 2007Inclui bibliografi

Beiträge zur deutschen Grammatik: Gesammelte Schriften von Tilman N. Höhle

A new edition of this book is available at&nbsp; http://langsci-press.org/catalog/book/234. This volume contains the complete collection of published and unpublished work on German grammar by Tilman N. Höhle. It consists of two parts. The first part is Topologische Felder, a book-length manuscript that was written in 1983 but was never finished nor published. It is a careful examination of the topological properties of German sentences, including a discussion of typological assumptions. The second part assembles all other published and unpublished papers by Höhle on German grammar.All of these papers were highly influential in German linguistics, in theoretical linguistics in general, and in a specific variant of theoretical linguistics, Head-Driven Phrase Structure Grammar. Topics covered are clause structure, constituent order, coordination, (verum) focus, word structure, the relationship between relative pronouns and verbs in V2, extraction, and the foundations of a theory of phonology in constraint-based grammar. &nbsp; As per legal requirement, we state that this book is available in Germany for 70 EUR

Beiträge zur deutschen Grammatik: Gesammelte Schriften von Tilman N. Höhle

This volume contains the complete collection of published and unpublished work on German grammar by Tilman N. Höhle. It consists of two parts. The first part is Topologische Felder, a book-length manuscript that was written in 1983 but was never finished nor published. It is a careful examination of the topological properties of German sentences, including a discussion of typological assumptions. The second part assembles all other published and unpublished papers by Höhle on German grammar.All of these papers were highly influential in German linguistics, in theoretical linguistics in general, and in a specific variant of theoretical linguistics, Head-Driven Phrase Structure Grammar. Topics covered are clause structure, constituent order, coordination, (verum) focus, word structure, the relationship between relative pronouns and verbs in V2, extraction, and the foundations of a theory of phonology in constraint-based grammar. This book is a revised version of http://langsci-press.org/catalog/book/149 As per legal requirement, we state that this book is available in Germany for 55 EUR

Beiträge zur deutschen Grammatik: Gesammelte Schriften von Tilman N. Höhle

This volume contains the complete collection of published and unpublished work on German grammar by Tilman N. Höhle. It consists of two parts. The first part is Topologische Felder, a book-length manuscript that was written in 1983 but was never finished nor published. It is a careful examination of the topological properties of German sentences, including a discussion of typological assumptions. The second part assembles all other published and unpublished papers by Höhle on German grammar.All of these papers were highly influential in German linguistics, in theoretical linguistics in general, and in a specific variant of theoretical linguistics, Head-Driven Phrase Structure Grammar. Topics covered are clause structure, constituent order, coordination, (verum) focus, word structure, the relationship between relative pronouns and verbs in V2, extraction, and the foundations of a theory of phonology in constraint-based grammar. This book is a revised version of http://langsci-press.org/catalog/book/149 As per legal requirement, we state that this book is available in Germany for 55 EUR

Beiträge zur deutschen Grammatik: Gesammelte Schriften von Tilman N. Höhle

This volume contains the complete collection of published and unpublished work on German grammar by Tilman N. Höhle. It consists of two parts. The first part is Topologische Felder, a book-length manuscript that was written in 1983 but was never finished nor published. It is a careful examination of the topological properties of German sentences, including a discussion of typological assumptions. The second part assembles all other published and unpublished papers by Höhle on German grammar.All of these papers were highly influential in German linguistics, in theoretical linguistics in general, and in a specific variant of theoretical linguistics, Head-Driven Phrase Structure Grammar. Topics covered are clause structure, constituent order, coordination, (verum) focus, word structure, the relationship between relative pronouns and verbs in V2, extraction, and the foundations of a theory of phonology in constraint-based grammar. This book is a revised version of http://langsci-press.org/catalog/book/149 As per legal requirement, we state that this book is available in Germany for 55 EUR

Beiträge zur deutschen Grammatik: Gesammelte Schriften von Tilman N. Höhle

This volume contains the complete collection of published and unpublished work on German grammar by Tilman N. Höhle. It consists of two parts. The first part is Topologische Felder, a book-length manuscript that was written in 1983 but was never finished nor published. It is a careful examination of the topological properties of German sentences, including a discussion of typological assumptions. The second part assembles all other published and unpublished papers by Höhle on German grammar.All of these papers were highly influential in German linguistics, in theoretical linguistics in general, and in a specific variant of theoretical linguistics, Head-Driven Phrase Structure Grammar. Topics covered are clause structure, constituent order, coordination, (verum) focus, word structure, the relationship between relative pronouns and verbs in V2, extraction, and the foundations of a theory of phonology in constraint-based grammar. This book is a revised version of http://langsci-press.org/catalog/book/149 As per legal requirement, we state that this book is available in Germany for 55 EUR

Beiträge zur deutschen Grammatik: Gesammelte Schriften von Tilman N. Höhle

This volume contains the complete collection of published and unpublished work on German grammar by Tilman N. Höhle. It consists of two parts. The first part is Topologische Felder, a book-length manuscript that was written in 1983 but was never finished nor published. It is a careful examination of the topological properties of German sentences, including a discussion of typological assumptions. The second part assembles all other published and unpublished papers by Höhle on German grammar.All of these papers were highly influential in German linguistics, in theoretical linguistics in general, and in a specific variant of theoretical linguistics, Head-Driven Phrase Structure Grammar. Topics covered are clause structure, constituent order, coordination, (verum) focus, word structure, the relationship between relative pronouns and verbs in V2, extraction, and the foundations of a theory of phonology in constraint-based grammar. This book is a revised version of http://langsci-press.org/catalog/book/149 As per legal requirement, we state that this book is available in Germany for 55 EUR

Beiträge zur deutschen Grammatik: Gesammelte Schriften von Tilman N. Höhle

This volume contains the complete collection of published and unpublished work on German grammar by Tilman N. Höhle. It consists of two parts. The first part is Topologische Felder, a book-length manuscript that was written in 1983 but was never finished nor published. It is a careful examination of the topological properties of German sentences, including a discussion of typological assumptions. The second part assembles all other published and unpublished papers by Höhle on German grammar.All of these papers were highly influential in German linguistics, in theoretical linguistics in general, and in a specific variant of theoretical linguistics, Head-Driven Phrase Structure Grammar. Topics covered are clause structure, constituent order, coordination, (verum) focus, word structure, the relationship between relative pronouns and verbs in V2, extraction, and the foundations of a theory of phonology in constraint-based grammar. This book is a revised version of http://langsci-press.org/catalog/book/149 As per legal requirement, we state that this book is available in Germany for 55 EUR

Beiträge zur deutschen Grammatik: Gesammelte Schriften von Tilman N. Höhle

This volume contains the complete collection of published and unpublished work on German grammar by Tilman N. Höhle. It consists of two parts. The first part is Topologische Felder, a book-length manuscript that was written in 1983 but was never finished nor published. It is a careful examination of the topological properties of German sentences, including a discussion of typological assumptions. The second part assembles all other published and unpublished papers by Höhle on German grammar.All of these papers were highly influential in German linguistics, in theoretical linguistics in general, and in a specific variant of theoretical linguistics, Head-Driven Phrase Structure Grammar. Topics covered are clause structure, constituent order, coordination, (verum) focus, word structure, the relationship between relative pronouns and verbs in V2, extraction, and the foundations of a theory of phonology in constraint-based grammar. This book is a revised version of http://langsci-press.org/catalog/book/149 As per legal requirement, we state that this book is available in Germany for 55 EUR