Submitted in fulfillment for the Master’s Degree in Food Science and Technology, Durban University of Technology, 2017. / Amadumbe commonly, known as taro is a traditionally underutilised tuber crop in Southern Africa. Nutritionally, amadumbe corms contain appreciable levels of carbohydrate mainly in the form of starch which is resistant to digestion. It also contains mucilage, a soluble fibre, which is good for the human digestive health. Thus, amadumbe starch and mucilage can be used as functional ingredients in food formulations. The aim of this research was to investigate the effects of genotypes and growth location on the physicochemical properties of amadumbe flour and starch. Eighteen (18) amadumbe genotypes grown in Roodeplaat, Gauteng and Umbumbulu, Kwazulu-Natal, South Africa, were studied. Roodeplaat received a lower annual average rainfall (514 mm) and high environmental temperature (24oC) compared to Umbumbulu (828 mm, 19oC) during the cropping season. Specifically, the influence of growth location and genotypes on the chemical composition (proximate composition and mineral contents) as well as the functional properties of amadumbe flours were investigated. Furthermore, starch was extracted and its physicochemical and functional properties were also studied. The carbohydrate contents (73-81%) of amadumbe flours were substantially high and varied with growth location. Mucilage contents (6-9%) were very low across genotypes in both locations. Water absorption and oil absorption capacities positively correlated to carbohydrates and mucilage in the flour irrespective of growth locations. Swelling power and solubility index was influenced by the amylose content of the flour. Genotype and growth location significantly affected the pasting properties of amadumbe flour. The pasting temperature was very high (approx. 90oC) across genotypes in both locations, while peak viscosity differed significantly (54-242 RVU) for genotypes grown in different environments. The amylose contents (0-14.4%) of amadumbe starches were low and varied significantly with growth location and among genotypes. Three genotypes, G2, G20, and G21 grown in Roodeplaat lacked amylose. Amadumbe starches showed reflective peaks at 2θ=15o and doublet at 17o, 18o and 24o typical of A-type starches. Amadumbe genotypes had small sized (1-5 µm) and polygonal starch granules. Functional properties including water absorption, swelling power, gelatinisation temperature and peak viscosity significantly positively correlated with amylose content. These findings further suggest that water availability could have a major effect on starch synthesis as the two locations received a different amount of rainfall during the growing season. Findings from this study are important for future improvement programmes and selection of appropriate genotypes for industrial production or food application of amadumbe flour and starch. / M

Cocoyam [Colocasia esculenta (L.) Schott] is widely cultivated as a staple food in the tropical and subtropical regions of the world. The crop, however, remains unpopular and not well known outside KwaZulu-Natal Province of South Africa where it is cultivated mainly for subsistence. The aims of the study were to collect local landraces (accessions) of the crop from where it is found growing within the country for various studies and also to document its nutritional values as well as the safety/toxicity of the crop. The study was carried out using various methods. These included a comparative assessment of the proximate, mineral and antinutrient compositions of cooked and uncooked tubers of a typical commercially available cocoyam and potato found in South African markets. These investigations were repeated for the tubers and leaves of available landraces (seven accessions) of C. esculenta found growing in the farmers’ fields in KwaZulu-Natal Province. Also, an in vivo toxicological study on cooked accessions of the local landraces was conducted to determine possible toxicity effects after consumption using albino rats as a model. The results revealed that commercially available cocoyam and potato tubers have very close nutritional components. Analysis of the proximate composition of seven accessions (UFCe1- UFCe7) of cooked and uncooked tubers of cocoyam indicated that UFCe7 was better in ash, crude protein, crude fibre and crude lipid contents but with higher moisture which could make it more vulnerable to microbial attack. No tubers of the seven accessions appeared to be ii outstandingly better than the others based on their mineral compositions. However, in terms of antinutritional factors, UFCe1, UFCe3 and UFCe7 had the least amounts of oxalate, tannins and phytate in their cooked states. It was discovered however, that the leaves of the accessions of this vegetable contain substantial amount of minerals, and therefore, can contribute significantly to the nutrient requirements of humans and could be recommended as a cheap source of nutrients in South Africa. None of the accessions was outstandingly better than the others in terms of their mineral contents and anti-nutritional factors. Moreover, the current study has shown that boiling the leaves of cocoyam prior to consumption is an effective way of reducing the antinutrient contents of the leaves of the plant thereby making it safe for consumption. The findings also revealed that cooking C. esculenta leaves may increase the levels of protein, fibre and lipid contents while cooking may also decrease the mineral, carbohydrate and caloric contents of the leaves of the accessions. The leafy vegetable may, therefore, be recommended as a cheap source of plant protein. Cooking improved the nutritive value as a result of the reduction in antinutrient levels, thereby improving the food quality in all the tuber and leaf samples used for this study. At the same time, cooked samples also suffered loss of some nutrients with respect to the proximate and mineral compositions. However, supplementation from other food sources that are rich in these nutrients is necessary when these crops are cooked for consumption. Any of the cocoyam accessions may be recommended for consumption for improved protein and mineral nutrients while tubers of accession UFCe7 have also shown good promise in terms of protein and fibre content availability. The results of the in vivo study, using the liver and kidney functional endpoints of weanling albino rats (Rattus norvegicus) maintained on different accessions of cooked cocoyam-based iii diets (UFCe1-UFCe7) for 28 days, revealed that all the accessions produced selective alterations on the hepatorenal indices of weanling rats. The highest alterations were produced by UFCe4 while the least was from UFCe2. These alterations may have consequential effects on the normal functioning of the liver and kidney of the animals. The UFCe2 exhibited the least toxicity risk among the accessions of C. esculenta growing in KwaZulu-Natal Province of South Africa.

Thesis--PlanA (M.S.)--University of Wisconsin--Stout, 2000. / Includes bibliographical references.

Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 66-68). / x, 68 leaves, bound col. ill. 29 cm

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 390-399).

No description available.

L’étude de l’optimisation des paramètres de production et de conservation de la farine de taro (Colocasia esculenta) a permis de mieux comprendre le processus cuisson des tubercules et de conservation des farines. Les études de cuisson des tubercules de six variétés ont montré que la variété Ibo coco est celle qui cuit vite eu égard à ses bonnes propriétés thermiques. La cuisson des tubercules dans l’eau du robinet est la meilleure technique de cuisson comparativement aux cuissons, à la vapeur, dans les solutions acides de citron et de tamarin. Les études de détermination des conditions optimales de séchage et conservation de la farine de taro, en utilisant un vieillissement accéléré à 10 et 20 jours de stockage à 45°C à des activité en eau de 0,07 ; 0,11 ; 0,23 ; 0,33 ; 0,53 ont permis de montrer que le vieillissement après 10 jours de stockage était suffisant pour les analyses. De plus l’application du modèle BET lors des mesures des isothermes de sorption, a permis de déterminer les teneurs en eau mono moléculaires théorique et expérimentale. Les farines produites à la teneur en eau mono moléculaire, donnent une pâte ayant des caractéristiques texturales proches de celles de la pâte traditionnelle. Toutefois, la conservation de ces farines à différentes fractions particulaires (75, 150 et 250 µm) montre que les petites fractions particulaires (75 µm) absorbent plus vite de l’eau que les autres fractions particulaires et sont de ce fait plus susceptibles à la détérioration / Study on optimization of production and storage parameters of the taro (Colocasia esculenta) flour permitted to better understanding the cooking process of taro tubers and storage of taro flours. Studies of cooking of six varieties of tubers showed that the variety Ibo coco had high rate of cooking, due to his good thermal properties. The cooking of tubers in the faucet water is the best technique of cooking compared to, steam cooking, lemon and tammarin cooking. Studies of determination of the optimal conditions of drying and storage of the taro flour, using an accelerated ageing to 10 and 20 days of storage at 45°C to the activity in water of 0,07; 0,11; 0,23; 0,33; 0,53, showed that the ageing after 10 day of storage was sufficient for analyses. Besides the use of the BET model on sorption isotherms, permitted to obtain values of theorical and experimental monolayer water. Flours produced at this monolayer water, give dough with the textural characteristics near of those of traditional dough. However, the storage of these flours with different particle sizes (75, 150 and 250 µm) shown that the small particle size (75 µm) absorb water quickly than other flours, and they are more susceptible to the deterioration

Submitted by Verônica Esteves (vevenesteves@gmail.com) on 2018-01-11T14:58:38Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação Letícia Pessôa.pdf: 1352120 bytes, checksum: eca0d4711a74743902585656f8314b58 (MD5) / Approved for entry into archive by Verônica Esteves (vevenesteves@gmail.com) on 2018-01-11T14:58:52Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação Letícia Pessôa.pdf: 1352120 bytes, checksum: eca0d4711a74743902585656f8314b58 (MD5) / Made available in DSpace on 2018-01-11T14:58:52Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação Letícia Pessôa.pdf: 1352120 bytes, checksum: eca0d4711a74743902585656f8314b58 (MD5) Previous issue date: 2017 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A infância e adolescência são estágios da vida essenciais para a formação de hábitos alimentares saudáveis. Por isso, o oferecimento de variações alimentares auxilia nesse aspecto, demostrando sua importância. Diversos alimentos possuem nutrientes que podem auxiliar tanto no tratamento como na prevenção de diversas doenças. Com isso, destacamos o taro, que é um tubérculo rico em nutrientes, destacando-se pelo seu conteúdo de vitaminas, minerais e fitoquímicos, que são fundamentais para o desenvolvimento corpóreo e ósseo durante esse estágio da vida. Dessa forma, o objetivo desse estudo foi avaliar o efeito da farinha de taro (Colocasia esculenta) sobre a composição corporal e óssea de ratos machos Wistar aos 90 dias de idade. Ao nascimento, cada mãe permaneceu com 6 filhotes que, ao completarem 21 dias, foram divididas em 2 grupos: grupo controle, que foi tratado com ração controle (GC, n=12), e o grupo experimental, tratado com a ração contendo 25% de farinha de taro (GE, n=12). Ao longo do experimento, foram analisados, semanalmente, a ingestão alimentar (g), comprimento (cm) e a massa corporal (g). Uma semana antes da eutanásia, foi realizada a curva glicêmica. Aos 90 dias de vida, os animais foram anestesiados com injeção intraperitoneal de Thiopentax® para a avaliação da composição corporal através do Absorciometria com dupla emissão de raios-X (DXA). A eutanásia foi realizada através da retirada do sangue, coletado por punção cardíaca para a realização das análises sorológicas. O tecido adiposo, o fêmur direito e a quarta vértebra lombar foram coletados para análises posteriores. Diferença significativa foi considerada quando p<0,05. Durante o estudo, foi observado que o GE apresentou maior massa corporal (p<0,001). Em relação à curva glicêmica não foi observado diferença significativa entre os grupos. Nos dados sorológicos, não houve diferença significativa de colesterol total, HDL, triglicerídeos e insulina. Porém os níveis de osteocalcina plasmática (+68%, p=0,0012) foram maiores no GE. Com o resultado do DXA, o GE mostrou maior massa magra (+11%, p=0,0015), gorda (+38%, p=0,0004), densidade mineral óssea (DMO) (+8%, p=0,0002), conteúdo mineral óssea (CMO) (+22%, p<0,0001) e área óssea total (+13%, p=0,0012). A massa absoluta (+56%, p=0,0005) e relativa (+34%, p=0,0061) da gordura intra-abdominal foi maior no GE. A análise da coluna (+12%, p=0,0006) e vértebra (+7%, p=0,0012) apontaram a DMO maior no GE. Em relação às análises e ao teste biomecânico do fêmur, o GE apresentou-se maior nos seguintes quesitos: peso (+14%, p=0,002), distância entre as epífises (+3%, p=0,019), ponto médio (+6%, p=0,006), DMO (+8%, p=0,0003) e força máxima (+10%, p=0,049). Esses resultados podem ser explicados devido ao alto conteúdo de fitoquímicos do taro, como a saponina e flavonoides, pois ambas atuam na composição corporal e tecido ósseo. Assim como, a presença de minerais, como cálcio, magnésio e fósforo, atuando na adequada mineralização óssea. Com isso, o taro pode ser considerado um bom auxiliador no desenvolvimento da composição corporal e óssea em ratos, porém mais estudos são necessários para melhor compreensão da atuação desses elementos. / The childhood and adolescence were life essential stage to formation of healthy eating habits. For this, offering of the foods variations helps in this aspect, demonstrated its importance. Several foods have nutrients that may help in the treatment and prevention of various diseases. Thereby, the taro is rich in several nutrients, as vitamin, minerals and phytochemicals. Being theses, fundamental to body and bone development during this life stage. In this way, the aim of this study was evaluated the effect of taro flour (Colocasia esculenta) upon body and bone composition of the males rats Wistar at 90 days of age. At born, each mother remained with 6 pups and, after that, were divided in 2 groups: control group, that was treated with diet control (CG, n=12) and experimental group, treated with diet content 25% of the taro flour (EG, n=12). Throughout the experiment, were analyzes weekly: food intake (g), length (cm) and body mass (g). One week before the euthanasia, was performed the glycemic curve. At 90 days, the animals were anesthetized with an intraperitoneal injection of Thiopentax ® and was submitted to body composition through DXA. The euthanasia was performed by removal blood, that was collected by cardiac puncture to serological test. The femur and fourth lumbar vertebra were collected to the analyze bone composition by Dual-energy ray absorptiometry (DXA) and biomechanical test. Differences were considered significant with p < 0.05. During this study, was observed that EG was higher values body mass (p<0.001) when compared to CG. In relation the glycemic curve, there wasn’t significant difference. Of serological data, there wasn’t significant difference of cholesterol, HDL, triglycerides and insulin, but levels of osteocalcin (+68%, p=0.0012) was higher in EG. Results of DXA, EG was higher: lean (+11%, p=0.0015) and fat (+38%, p=0.0004) mass, bone density mineral (BMD) (+8%, p=0.0002) and content (BMC) (+22%, p<0.0001), bone area total (+13%, p=0.0012). Absolute (+56%, p=0.0005) and relative (+34%, p=0.0061) mass of intra-abdominal fat was higher in EG. Spine (+12%, p=0.0006) and vertebra (+7%, p=0.0012), BMD was higher in EG. In relation of analysis and biochemical test of femur, EG was higher in the following questions: mass (+14%, p=0.002), distance between epiphyses (+3%, p=0.019), midpoint of the diaphysis (+6%, p=0.006), BMD (+8%, p=0.0003) and maximum force (+10%, p=0.049). These results were observed due higher phytochemical content of taro, as saponins and flavonoids because both act in corporal composition of bone tissue. As, the minerals presence, as calcium, magnesium and potassium, contributing to adequate bone mineralization. Thereby, taro can be a good helper in the body and bone development in rats, but more studies were necessary for better understanding of these elements.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-04-24T13:17:50Z No. of bitstreams: 1 texto completo.pdf: 2075413 bytes, checksum: 43149ccec74c9149b6a512bbb4fb370d (MD5) / Made available in DSpace on 2017-04-24T13:17:50Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2075413 bytes, checksum: 43149ccec74c9149b6a512bbb4fb370d (MD5) Previous issue date: 1999-05-24 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Foi desenvolvido o método de itinerário fitotécnico (MITEC), multicriterial, interativo e informatizado, para avaliação da sustentabilidade, bem como para redução da subjetividade no diagnóstico e desenho de sistemas de produção (SP) personalizados. Ele é capaz de calcular o potencial relativo de sustentabilidade (PRS) de opções fitotécnicas em confronto, a partir de uma fórmula de ponderação com oito coeficientes. Este cálculo é executado por sistemas especialistas inseridos no programa, a partir de parametrizações de caráter temporal e hierárquico, feitas pelo agricultor, pela comunidade, pelo técnico e por banco de dados. Para isto, são definidas as condições de cenário e parametrizadas as funções de sustentabilidade, os fatores de produção e a disponibilidade de recursos materiais e humanos. Para experimentar o método, foi conduzido um experimento fatorial 2 x 5 x 4 (dois níveis profissionais, cinco tipos de perfis paradigmáticos e quatro tipos de SP), no delineamento em blocos ao acaso, com três repetições (agricultores). As avaliações foram feitas com cada extensionista junto a três produtores de inhame (Colocasia e sculenta Schott), selecionados entre nove entrevistados da sua área de ação, que possuíam diferentes níveis de preocupação com o campo social, ambiental ou econômico. Em cada unidade de produção foram definidos quatro SP: do agricultor (SPA), do técnico sem o método (SPT), do técnico com o método (ITECT) e do MITEC (ITECM). O método foi significativamente eficiente na avaliação e agregação de PRS aos diferentes SP. Comprovou- se a redução de subjetividade, não havendo diferença significativa entre o PRS médio dos ITECT em relação à média dos ITECM, independente- mente do nível profissional e do perfil paradigmático. / MITEC (Plant Production Systems Diagnostic & Design Method) was developed in a multicriterial, interactive and computerised way for sustainability evaluation, as well as for reduction of subjectiveness in the diagnosis and design of specific agricultural production systems (SP). This expert system can calculate the Relative Sustainability Potential Index (PRS) of each technical option, through weighting formulae taking into account 8 coefficients. This calculation is based on temporal and hierarchical character evaluations made by the grower, the community, the staff of extension service and the database. For that, are defined the scenario conditions and evaluated the sustainability functions, production factors, the availability of material and human resources. The method was tested through an factorial experiment - 2 x 5 x 4 (2 professional levels, 5 types of paradigmatic profiles and 4 types of SP) - in a randomised block design, with 3 replications. In each region, 3 taro (Colocasia esculenta Schott) agroecosystems were evaluated by one member of the technical staff. These agroecosystems were those whose growers showed special concern about social, environmental and economic issues. Four production systems were developed for each taro field: grower production system (SPA); extension staff member’s production system without MITEC support (SPT); extension staff member’s production system with MITEC support (ITECT), and the MITEC production system (ITECM). MITEC proved to be an efficient method to evaluate production systems and to aggregate PRS to them. It was also able to reduce subjectiveness.

Rapid advances continue in the acquisition 6f new fundamental knowledge of starch and a vigorous expansion in the use of starch is proceeding in both food and non-food applications. Results are here reported on starch-filled high density polyethylene which reveal reinforcement effects of starch on the thermoplastic. This significant development makes starch a most promising organic filler. This work is primarily a study of the mechanical and thermal properties of starch-filled high density polyethylene and attempts to identify changes caused in the structure of this polymer due to starch filler. Particular attention has also been given to changes in crystallinity and microscopic appearance. Because preliminary studies showed that enhanced effects were obtained when using starches of small particle size, much effort was given to developing a simple method of extraction of starches from the many varieties of Taro (Colocasia esculenta) plants in order to get the best possible yield and freedom from agglomerates. Because of the absence of recorded data it was necessary to study the physical properties of these starches. The theory and application of small-angle light scattering was reviewed because of its value as a technique for the characterization of starches and spherulitic polymer studies. One hundred and twelve Taro starches were characterized in terms of average particle sizes by the above technique. Starches with particle sizes ranging from 3 micron to 50 micron were investigated in order to establish the size/effect relationship in starch polymer composites. Methods of increasing the adhesion between filler and polymer matrix have also been studied, as has also the stripping of amylopectin from starch grains by cold acid treatment. Acid treatment, surprisingly, produced composites of increased mechanical strength in high density polyethylene, implying that a true reinforcing filler has been created. Results from differential scanning calorimetry and x-ray diffraction studies revealed that an increase in degree of crystallinity in high density polyethylene was associated with the presence of starch.