Thesis (M. Phil.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 62-72).

Thesis (M.Sc.)--Memorial University of Newfoundland, 2004. / Bibliography: leaves 117-146.

Thesis (Ph. D.)--Columbia University, 1922. / Vita.

Thesis (M.S.) in Chemical Engeneering--University of Maine, 2004. / Includes vita. Includes bibliographical references (leaves 97-99).

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Starch is a polyglucan made up of the two glucose polymers, amylose and amylopectin. Plants use starch to store excess carbohydrates from photosynthesis which get used for growth during the night. Starch metabolism is well undertood in higher plants such as A. thaliana thaliana and Solanum tuberosum with well-established pathways worked out for the enzymes involved in its synthesis and degradation. The bryophyte Physcomitrella patens has emerged as a popular choice for studying gene function in lower plants both because its genome has been sequenced and because of the ease of establishing knockout mutants via homologous recombination. Many metabolic functions have been studied in P. patens but, until now, little has been done in examining starch metabolism in moss. This study focused on two enzymes that have been found to be involved in starch degradation in higher plants, Disproportionating enzyme 1 (DPE1) and Disproportionating enzyme 2 (DPE2). DPE1 isoforms have been found to break down malto-oligosaccharides, which are products of starch degradation, into glucose within the chloroplast. On the other hand DPE2 catabolizes maltose to glucose in the cytosol. Higher plants that were silenced in these two genes were unable to degrade starch effectively, which lead to an increase in starch, malto-oligosaccharides or maltose and reduced growth. Three orthologs were identified for DPE1 in P. patens (PpDPE1A, B and C) and one for DPE2 (PpDPE2). Only PpDPE1B and PpDPE1C were found to be expressed in P. patens at the beginning of the light period but further investigation would be necessary at different time points as these genes were shown to be optimally expressed at the end of the light period. Targeted gene knockouts were made for each in P. patens which showed a reduced growth phenotype for all, indicating that these genes do play a role in starch catabolism that influences growth. There was, however, no significant change in starch content between the mutant lines and wild type (Wt). GFP fusion proteins showed PpDPE2 to be localized in cytosol, in close proximity to the chloroplast membrane. Similar findings have been found for DPE2 in A. thaliana and S. tuberosum. We hypothesize that PpDPE2 may play a role in cold tolerance in moss as an increase in starch breakdown has been witnessed in cold treated moss as well as increased transcript levels of starch metabolism genes and a maltose transporter. This opens a door to the further study of these generated mutant lines under cold stress. / AFRIKAANSE OPSOMMING: Stysel is ‘n poliglukaan wat bestaan uit die twee glukose polimere: amilose en amilopektien. Plante gebruik stysel om oortollige koolhidrate van fotosintese wat vir groei gebruik word gedurende die nag te berg. Styselmetabolisme in hoër plante soos A. thaliana thaliana en Solanum tuberosum word goed verstaan, met gevestigde paaie uitgewerk vir die ensieme wat betrokke is by die sintese en afbreek daarvan. Die briofiet Physcomitrella patens is ‘n populêre keuse vir die bestudering van geenfunksie in laer plante, omdat die genoomvolgorde bepaal is en as gevolg van die gemak waarmee ‘uitklop’-mutante via homoloë rekombinasie gevorm kan word. Baie metaboliese funksies is bestudeer in P. patens maar tot nou is min gedoen om die styselmetabolisme in mos te ondersoek. Hierdie studie het gefokus op twee ensieme, DPE1 and DPE2, wat gevind is om betrokke is afbreek van stysel in hoër plante. Dit is voorheen bevind dat DPE1 isoforme malto-oligosakkariedes (wat produkte is van styselafbraak) afbreek na glukose in the chloroplast. Aan die ander kant kataboliseer DPE2 maltose na glukose in die sitosol. Hoër plante waarin hierdie gene stilgemaak is, is nie instaat daartoe om stysel effektief af te breek nie. Dit lei tot ‘n verhoging in stysel, malto-oligosakkariede of maltose en verminderde groei. Drie ortoloë is geïdentifiseer vir DPE1 in P. patens (PpDPE1A, B en C) en een vir DPE2 (PpDPE2). Slegs PpDPE1B en PpDPE1C word uitgedruk in P. patens aan die begin van die ligperiode, maar verder ondersoek sal nodig wees op verskillende tydpunte, omdat dit bewys is dat hierdie gene optimaal uitgedruk word tydens die einde van die ligperiode. Geteikende geen uiklop-mutante is gemaak vir elk in P. patens wat ‘n verminderde-groei fenotipe vertoon het vir almal, wat aandui dat hierdie gene ‘n rol speel in styselkatobolisme wat groei beïnvloed. Daar was egter geen beduidende verskil in styselinhoud van die mutante lyne en die wilde tipe nie. GFP-fusieproteïne het gewys dat PpDPE2 gelokaliseer is in die sitosol, naby aan die chloroplast membraan. Soorgelyke bevindinge is ook gemaak in DPE2 in A. thaliana en S. tuberosum. Dit word gestel dat PpDPE2 moontlik ‘n rol speel in kouetoleransie in moss, omdat ‘n verhoging in styselafbraak opgemerk is in koue-behandelde moss sowel as verhoogde transkripsievlakke van styselmetabolisme gene en ‘n maltose transporter. Dit maak ‘n deur oop vir verdere studie van hierdie gegenereerde mutant-lyne onder kouestres.

Orientador: Carlos José Leopoldo Constantino / Banca: Antonio José Félix de Carvalho / Banca: Neri Alves / Banca: Hermann Bremer Neto / Banca; Rebeca Delatore Simões / O Programa de Pós Gradução em Ciência e Tecnologia de Materiais, PosMat, tem carater institucional e integra as atividades de pesquisa em materiais de diversos campi / Abstract: Foams of PLA/Starch and PLA/Starch/Sepiolite (SEP) with different compositions were produced. The following techniques were used in the samples characterization: i) scanning electron microscopy (SEM); ii) density (ρ) measures; iii) differential scanning calorimetry (DSC), iv) mechanical analysis (flexion and traction); v) dynamic mechanical thermal analysis (DMTA); vi) in vivo test. In the SEM images, in both foams and precursors, the interface between the phases was eminently physic with two distinct phases with gaps between them, and an increase in size of the gaps was observed in the foam. It was observed that in the sampleswith SEP occurred greater generation of smaller cell and more compact. This demonstrates that SEP presented, as well as the starch granules, the nucleating agent behavior. In ρ measures the lowest values were found in samples originating from the autoclave and glycerine bath, respectively. These decreases were consistent with the expansion of PLA matrix observed in the SEM images. In the DSC measurements in general, the starch addition to PLA resulted in increased Xc. This effect happened because the interface between starch and PLA be moreenergetic, which facilitated the crystals formation in the PLA matrix. In composites containing SEP, generally larger Xc values were observed when compared with the PLA/starch blends in the same proportions materials. This behavior is probably related to the effect of the SEP as a nucleating agent in the PLA. In t... (Complete abstract click electronic access below) / Resumo: Espumas de PLA/Amido e PLA/Amido/Sepiolita (SEP) com distintas composições foram produzidas. As amostras foram caracterizadas pelas seguintes técnicas: i) microscopia eletrônica de varredura (MEV); ii) medidas de densidade (ρ); iii) calorimetria diferencial exploratória (DSC), iv) análise mecânica (flexão e tração); v) análise térmica dinâmico mecânica (DMTA); vi) testes in vivo. Nas imagens de MEV, tanto nos precursores quanto nas espumas, a interface entre as fases foi eminentemente física com duas fases distintas e houve ocorrência de lacunas entre elas, sendo que um aumento no tamanho das lacunas foi observado nas espumas. Observou-se que nas amostras com SEP ocorreu uma maior geração de células com menores dimensões e mais compactas. Isto demonstra que a SEP apresentou, assim como os grânulos de amido, o comportamento de agente de nucleação. Nas medidas de ρ os menores valores ocorreram com as amostras originárias do autoclave e do banho de glicerina, respectivamente. Essas diminuições foram consistentes com a expansão da matriz de PLA observada nas imagens de MEV. Nas medidas de DSC, em geral, a adição do amido ao PLA implicou no aumento da Xc. Tal efeito sucedeu-se devido a interface entre o amido e o PLA ser mais energética, o que facilitou a formação de cristais na matriz de PLA. Nos compósitos contendo SEP, em geral, maiores valores de Xc foram observados quando comparados com as blendas de PLA/amido nas mesmas proporções de materiais. Esse comportamento provavelm... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

The field of the Chemistry of Starch is so wide and the complexities involved are so great that any attempt to solve the problems of the constitution of starch cannot be spread over the whole front, but must necessarily be confined to a few chosen points of attack. The following introduction, therefore, is not presented as a complete survey of literature of the subject but merely as a resumé of those parts bearing immediately on the topics studies, with special reference to the work of Dr. J. K. Rutherford, inasmuch as the present thesis is a continuation and amplification of her work.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / FormulaÃÃes de tapiocas elaboradas com amido de batata e de milho com e sem adiÃÃo de Estearoil-2-lactil-2-lactato de SÃdio (SSL), foram submetidas à anÃlise de perfil de textura, grau de gelatinizaÃÃo, teor de amido resistente e analisada sensorialmente tendo como padrÃo uma formulaÃÃo de uma tapioca de mandioca comercial. Foi verificado que a tapioca de mandioca apresentou o maior grau de gelatinizaÃÃo (61,63%) dentre as tapiocas formuladas com os outros amidos mencionados, bem como o maior teor de amido resistente (42,23%). Os perfis de textura (dureza, elasticidade, coesividade, mastigabilidade, forÃa mÃxima de corte e gomosidade) das tapiocas com e sem SSL num tempo de armazenamento de 48 horas nÃo apresentaram diferenÃas significativas(intervalo de confianÃa 95%) ao serem comparados. Para as tapiocas sem adiÃÃo de SSL, os parÃmetros do perfil de textura apresentaram as seguintes variaÃÃes de valores: dureza (20,0-140,0 N), elasticidade (0,75-0, 90), (Coesividade) (0,5-0,80) mastigabilidade (10-60N), ForÃa mÃxima de corte (50-300N) e gomosidade (15-35N) e para as tapiocas com adiÃÃo de SSL: dureza (10-140N), elasticidade, (0,75-0,95) Coesividade (0,40-0,90) mastigabilidade (5-55), ForÃa mÃxima de corte (50-250N) e gomosidade ((15-35N)). Os resultados da anÃlise sensorial indicaram os seguintes resultados para os atributos analisados: aroma, a tapioca de milho =7, 03, aparÃncia-tapioca de mandioca =6, 70, cor-tapioca de mandioca=6,90; sabor-tapioca de milho=6,63; textura-tapioca de mandioca=5,98 e impressÃo global-tapioca de milho=6,0. Dos resultados obtidos, podemos concluir que à possÃvel elaborar tapiocas com outros amidos com as mesmas caracterÃsticas da tapioca tradicional formulada a partir do amido de mandioca. / The tapiocas were maked wiht potato starch and corn starch with and without Sodium Stearoyl-2Lactylate (SSL). Were evaluated the texture profile, degree of gelatinization, resistant starch and sensory analyzed. The tapioca with cassava showed the biggest degree of gelatinization(61,63%) and resistant starch(42,23%). The texture profile (hardeness, springness, cohesiveness, chewiness, force and gumminess).with and without SSL, didnÂt show with storage of 48 hours significant deference. without SSL, hardeness (20,0-140,0 N), springness (0,75-0, 90), cohesiveness (0,5-0,80) chewiness (10-60N), force (50-300N) e gumminess, (15-35N) and the sample with SSL: hardeness (10-140N), springness (0,75-0,95) (cohesiveness (0,40-0,90 chewiness (5-55), force (50-250N) e gomosidade ((15-35N)). The results of sensory showed for attributes: flavor, the tapioca of corn =7, 03, aspect,-tapioca of cassava =6, 70, color-tapioca of cassava=6,90; savor,r-tapioca of corn=6,63; texture-tapioca of cassava=5,98 e print global-tapioca of corn=6,0. According to the outcomes obtained we can accomplish with the others starches with the same characteristics, of cassava

This work investigates ways to prevent and manage hyperglycemia using preventive nutrition. Uncontrolled and chronic hyperglycemia is a global health issue leading to many health problems including diabetes. This thesis details the manipulation of highly retrograded starch particles in order to produce particles that are digested slowly to release glucose at a prolonged and moderate rate to prevent this. The first section of this study utilized acid hydrolysis to alter starch structure and change digestibility. The hydrolysis treatment showed that hydrolysis of native starch prior to particle formation changed the structure in a way that increased digestibility. The second section of this work introduced polyphenols into the particles which only a marginal effect on digestion. Overall the actual process of retrograding and making the particles themselves appeared to create particles that were more resistant to digestion. These could be used in a product to deliver a moderate glycemic response.