Typescript (photocopy). / Digitized by Kansas Correctional Industries

published_or_final_version / Botany / Master / Master of Philosophy

Thesis (M. Phil.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 208-219).

M.S.

No description available.

Call number: LD2668 .T4 1985 M375 / Master of Science

A mandioca (Manihot sculenta Crantz) é originária do Brasil e é também cultivada em outros países de clima tropical, tendo grande importância como fonte de carboidratos e de subsistência para quase um bilhão de pessoas. As suas raízes são altamente perecíveis, pois após três dias da colheita inicia-se o processo de deterioração fisiológica. Métodos e produtos que possam aumentar a vida de prateleira da mandioca ou a disponibilidade de produtos à base de mandioca são de grande interesse para produtores e industriais. Este trabalho teve como objetivo o desenvolvimento de um novo produto moldado na forma de chips e frito, elaborado a partir de mandioca crua e cozida em pó, com uso mínimo de ingredientes, isento de glúten, gordura trans e ingredientes de origem animal, numa tentativa de fornecer ao mercado um produto com maior valor agregado e que possa ser produzido por pequenas e micro empresas. O estudo foi conduzido em duas etapas, na primeira obteve-se a mandioca cozida em pó e foram realizados os pré-testes de formulação e processamento dos chips e na segunda etapa foi realizado o aprimoramento da formulação e estudo de vida de prateleira da mandioca chips. Na primeira etapa a análise sensorial preliminar apontou a aparência gordurosa e a falta de gosto de sal como pontos a serem melhorados na formulação, porém foi possível produzir mandioca chips com o uso de mandioca cozida em pó a partir da variedade IAC 576-70 e Manteiga. Na segunda etapa o óleo de soja foi substituído por gordura de palma, o teor de sal foi aumentado e para o aprimoramento da formulação e processo foram testadas as condições de tempo e temperatura de fritura, e a adição de mandioca crua em pó, a partir de um planejamento experimental fatorial completo 23 com 6 pontos axiais e 3 repetições do ponto central, totalizando 17 ensaios (T1 a T17) com as variáveis independentes: mandioca crua em pó, mandioca cozida em pó e tempo de fritura. As variáveis dependentes foram: absorção de lipídeos; umidade; atividade de água; textura; cor e volume específico. A adição de mandioca crua em pó altera as propriedades reológicas, sensoriais e tecnológicas dos chips. Há uma forte correlação negativa entre a porcentagem de lipídeos e de umidade. A textura dos chips foi influenciada pelo tempo de fritura e quantidade de mandioca cozida em pó. Três testes foram selecionados para análise sensorial de aceitação sendo escolhido o teste T5, que foi submetido ao estudo de vida de prateleira. Durante este estudo não houve alteração na umidade, atividade de água e textura instrumental da mandioca chips indicando que a embalagem utilizada (sacos de PEAD/Al/PPMO) foi eficiente. No estudo de estabilidade oxidativa durante o armazenamento, em relação ao índice de acidez, este aumentou nos primeiros 29 dias de estocagem e depois se manteve constante. O índice de peróxidos atingiu seus maiores valores após 56 dias de armazenamento diminuindo ao final nos 133 dias de armazenamento. Não houve alteração nos valores de TBARS (substâncias reativas ao ácido tiobarbitúrico), dienos e trienos conjugados durante o estudo de vida de prateleira. A análise sensorial realizada para determinar a vida de prateleira da mandioca chips considerando o método de aceitação da Aceitabilidade Mínima Tolerável e o método de comparação das amostras com o padrão (0 dia de armazenamento) apontaram 56 dias como o tempo, a partir do qual, são percebidas as alterações nos atributos avaliados. / Cassava (Manihot sculenta Crantz) is native to Brazil and is also cultivated in other tropical countries, having great importance as a source of carbohydrates and as a subsistence crop for nearly a billion people. Its roots are highly perishable, since after three days from the harvest it begins the process of physiological deterioration. Methods and products that may increase the shelf life of cassava or the availability of cassava-based products are of great interest to producers and industries. This study aimed to develop a new product in the form of chips molded and fried chips, made from raw and cooked cassava powder, with minimum use of ingredients, free of gluten, Trans fat and animal ingredients in an attempt to provide to the market a product with higher added value and that can be produced by small and micro enterprises. The study was conducted in two steps, in the first one, it was obtained the powder of cooked cassava and a pre-formulation and processing of the chips was carried out and a second step was carried out in order to improve the formulation and study the shelf life of cassava chips. In the first step preliminary sensory analysis pointed the greasy appearance and lack of salty taste as aspects to be improved in further formulation, but it was possible to produce cassava chips with the use of cooked cassava powder from the variety IAC 576-70 and the variety \"Butter\". In the second stage soybean oil was replaced with palm oil, and the salt content was increased and to improve the formulation and process conditions, frying time and temperature, and the addition of raw cassava powder were tested, from a experimental design 23 full factorial with six axial points and three repetitions of the central point, resulting in 17 trials (T1 to T17) with the independent variables: raw cassava powder, cooked cassava powder and frying time. The dependent variables were: absorption of fat, moisture, water activity, texture, color and specific volume. The addition of raw cassava powder changes the rheological, sensory and technological properties of the chips. There is a strong negative correlation between the percentage of lipids and moisture. The texture of the chips was influenced by the frying time and the amount of cooked cassava powder. Three tests were selected for sensory analysis of acceptance test, among them T5 was chosen, which was submitted to the shelf life study. During this study there was no change in moisture, water activity and instrumental texture of cassava chips indicating that the packaging used (plastic bags, HDPE / Al / MEPP) was efficient. In the study of oxidative stability during storage, compared with the acidity index, this increased in the first 29 days of storage and then remained constant. The peroxide value reached its highest values after 56 days of storage and decreased at the end of 133 days of storage. There was no change in the values of TBARS (thiobarbituric acid reactive substances), conjugated diene and triene during the shelf life study. The sensory analysis carried out to determine the shelf life of cassava chips considering the method of acceptance of Minimum Tolerable Acceptability and the method of comparing with standard samples (0 day of storage) pointed out 56 days as the time from which changes in its attributes are perceived.

A mandioca (Manihot sculenta Crantz) é originária do Brasil e é também cultivada em outros países de clima tropical, tendo grande importância como fonte de carboidratos e de subsistência para quase um bilhão de pessoas. As suas raízes são altamente perecíveis, pois após três dias da colheita inicia-se o processo de deterioração fisiológica. Métodos e produtos que possam aumentar a vida de prateleira da mandioca ou a disponibilidade de produtos à base de mandioca são de grande interesse para produtores e industriais. Este trabalho teve como objetivo o desenvolvimento de um novo produto moldado na forma de chips e frito, elaborado a partir de mandioca crua e cozida em pó, com uso mínimo de ingredientes, isento de glúten, gordura trans e ingredientes de origem animal, numa tentativa de fornecer ao mercado um produto com maior valor agregado e que possa ser produzido por pequenas e micro empresas. O estudo foi conduzido em duas etapas, na primeira obteve-se a mandioca cozida em pó e foram realizados os pré-testes de formulação e processamento dos chips e na segunda etapa foi realizado o aprimoramento da formulação e estudo de vida de prateleira da mandioca chips. Na primeira etapa a análise sensorial preliminar apontou a aparência gordurosa e a falta de gosto de sal como pontos a serem melhorados na formulação, porém foi possível produzir mandioca chips com o uso de mandioca cozida em pó a partir da variedade IAC 576-70 e Manteiga. Na segunda etapa o óleo de soja foi substituído por gordura de palma, o teor de sal foi aumentado e para o aprimoramento da formulação e processo foram testadas as condições de tempo e temperatura de fritura, e a adição de mandioca crua em pó, a partir de um planejamento experimental fatorial completo 23 com 6 pontos axiais e 3 repetições do ponto central, totalizando 17 ensaios (T1 a T17) com as variáveis independentes: mandioca crua em pó, mandioca cozida em pó e tempo de fritura. As variáveis dependentes foram: absorção de lipídeos; umidade; atividade de água; textura; cor e volume específico. A adição de mandioca crua em pó altera as propriedades reológicas, sensoriais e tecnológicas dos chips. Há uma forte correlação negativa entre a porcentagem de lipídeos e de umidade. A textura dos chips foi influenciada pelo tempo de fritura e quantidade de mandioca cozida em pó. Três testes foram selecionados para análise sensorial de aceitação sendo escolhido o teste T5, que foi submetido ao estudo de vida de prateleira. Durante este estudo não houve alteração na umidade, atividade de água e textura instrumental da mandioca chips indicando que a embalagem utilizada (sacos de PEAD/Al/PPMO) foi eficiente. No estudo de estabilidade oxidativa durante o armazenamento, em relação ao índice de acidez, este aumentou nos primeiros 29 dias de estocagem e depois se manteve constante. O índice de peróxidos atingiu seus maiores valores após 56 dias de armazenamento diminuindo ao final nos 133 dias de armazenamento. Não houve alteração nos valores de TBARS (substâncias reativas ao ácido tiobarbitúrico), dienos e trienos conjugados durante o estudo de vida de prateleira. A análise sensorial realizada para determinar a vida de prateleira da mandioca chips considerando o método de aceitação da Aceitabilidade Mínima Tolerável e o método de comparação das amostras com o padrão (0 dia de armazenamento) apontaram 56 dias como o tempo, a partir do qual, são percebidas as alterações nos atributos avaliados. / Cassava (Manihot sculenta Crantz) is native to Brazil and is also cultivated in other tropical countries, having great importance as a source of carbohydrates and as a subsistence crop for nearly a billion people. Its roots are highly perishable, since after three days from the harvest it begins the process of physiological deterioration. Methods and products that may increase the shelf life of cassava or the availability of cassava-based products are of great interest to producers and industries. This study aimed to develop a new product in the form of chips molded and fried chips, made from raw and cooked cassava powder, with minimum use of ingredients, free of gluten, Trans fat and animal ingredients in an attempt to provide to the market a product with higher added value and that can be produced by small and micro enterprises. The study was conducted in two steps, in the first one, it was obtained the powder of cooked cassava and a pre-formulation and processing of the chips was carried out and a second step was carried out in order to improve the formulation and study the shelf life of cassava chips. In the first step preliminary sensory analysis pointed the greasy appearance and lack of salty taste as aspects to be improved in further formulation, but it was possible to produce cassava chips with the use of cooked cassava powder from the variety IAC 576-70 and the variety \"Butter\". In the second stage soybean oil was replaced with palm oil, and the salt content was increased and to improve the formulation and process conditions, frying time and temperature, and the addition of raw cassava powder were tested, from a experimental design 23 full factorial with six axial points and three repetitions of the central point, resulting in 17 trials (T1 to T17) with the independent variables: raw cassava powder, cooked cassava powder and frying time. The dependent variables were: absorption of fat, moisture, water activity, texture, color and specific volume. The addition of raw cassava powder changes the rheological, sensory and technological properties of the chips. There is a strong negative correlation between the percentage of lipids and moisture. The texture of the chips was influenced by the frying time and the amount of cooked cassava powder. Three tests were selected for sensory analysis of acceptance test, among them T5 was chosen, which was submitted to the shelf life study. During this study there was no change in moisture, water activity and instrumental texture of cassava chips indicating that the packaging used (plastic bags, HDPE / Al / MEPP) was efficient. In the study of oxidative stability during storage, compared with the acidity index, this increased in the first 29 days of storage and then remained constant. The peroxide value reached its highest values after 56 days of storage and decreased at the end of 133 days of storage. There was no change in the values of TBARS (thiobarbituric acid reactive substances), conjugated diene and triene during the shelf life study. The sensory analysis carried out to determine the shelf life of cassava chips considering the method of acceptance of Minimum Tolerable Acceptability and the method of comparing with standard samples (0 day of storage) pointed out 56 days as the time from which changes in its attributes are perceived.

Background: With an estimated number of 1.2 billion in the world, adolescents represent a major transformative force in global health. Optimum adolescent nutrition is increasingly important for scaling up population health gains in low- and middle-income countries (LMICs) of South Asia. Nevertheless, little is known about the gender and socio-economic stratification of diets consumed by rural adolescents in these countries. The aim of this project was to understand the gender and socio-economic stratification of their diet with a dual, descriptive-analytic focus on dietary diversity (DD) and consumption of ultra-processed and deep-fried foods. Methods: This thesis builds upon cross-sectional analyses of data collected during 15-year follow-up of the MINIMat (Maternal and Infant Nutrition Interventions in Matlab) trial, from September 2017 to June 2019. Data on dietary and socio-demographic variables were collected through household survey; using a pre-tested, structured questionnaire. A single, 24-hour recall was employed to assess consumption of staples and non-staples arranged in 10 groups, ultra-processed foods (UPF) in four groups, and of one group of deep-fried foods. Data were analyzed using logistic regression models. The analytic sample comprised 2463 adolescents. Results: The prevalence of inadequate DD was 42.3% (40.3-44.2). Consumption of dark green leafy vegetables, vitamin A-rich fruits and vegetables, and animal-source foods–except fish–appeared low. The proportions of adolescents consuming meat, egg and dairy were higher among those from the richest households than those from the poorest households, and among boys than girls. Belonging to the poorest households (adjusted odds ratio (aOR): 1.59; 95% confidence interval (CI): 1.27-2.00) and the food insecure households (aOR: 1.34; 95% CI: 1.13-1.59), and attaining secondary education (aOR: 1.38; 95% CI: 1.11-1.71) were positively associated with inadequate DD. Adolescents having mothers with secondary education or above had lower odds of inadequate DD (aOR: 0.76; 95% CI: 0.60-0.96). Gender was not an independent predictor of inadequate DD.Approximately 83% (81.5-84.4) adolescents reportedly consumed at least one ultra-processed or deep-fried food in the 24 hours preceding the survey. Packaged confectioneries were the most consumed and sugar-sweetened beverages (SSB) the least consumed UPF group. Boys had greater odds of consumption than girls for all UPF groups and deep-fried foods. The association was strongest for SSB (aOR: 2.57; 95% CI: 1.97, 3.37), followed by deep-fried foods (aOR 1.96; 95% CI: 1.66, 2.32). Belonging to the richest households was associated with consumption of ready-to-eat foods (aOR 1.55; 95% CI: 1.12-2.16) and of SSB (aOR: 1.44; 95% CI: 1.02-2.03). Adolescents with higher educational attainment had lower odds of consuming SSB (aOR 0.73; 95% CI: 0.54-0.98). Conclusion: The studies presented compelling evidence of limited DD concurrent with emergent consumption of ultra-processed and deep-fried foods in a rural cohort of adolescents. Inadequate DD was more likely among those from the poorest and the food insecure households. For ultra-processed and deep-fried foods, gender association persisted across the food groups with boys having a greater likelihood of consumption than girls. Wealth status influenced consumption of “instant” foods and SSB only. This suboptimal dietary pattern may place the adolescents at heightened risk of different forms of malnutrition.