Call number: LD2668 .T4 1985 W8 / Master of Science

It is estimated that over 30 million people are exposed to arsenic from drinking contaminated groundwater in Bangladesh. Furthermore, due to the use of contaminated water for irrigation purposes, arsenic and other toxic elements are entering the food chain of Bangladeshis. In this thesis, the total levels of toxic elements (As, Cd, Pb) and essential elements (Mn, Se, Zn) in 1,120 samples of Bangladeshi foods (including rice, vegetables, fish) and non-foods (betel quid and baked clay) imported into the United Kingdom were determined. From this analysis, it is concluded that Bangladeshis are exposed to high levels of toxic elements. Inorganic arsenic levels in Bangladeshi rice can be very high, especially from regions with high arsenic in groundwater. However, there is a lack of studies in the literature regarding arsenic levels in rice from regions in Bangladesh with relatively low levels of arsenic in the groundwater. Therefore, rice from one such region (Sylhet district) was analysed. The results indicated that boro (mean 71.7 µg/kg) and aman (mean 85.7 µg/kg) rice from Sylhet contained between 2 to 4-fold lower levels of arsenic, compared to other regions of Bangladesh thus far reported in the literature. Arsenic speciation was carried out on a selection of rice (aromatic and non-aromatic) from Sylhet region and this revealed 70% (mean value) as inorganic arsenic (AsIII and AsV), which is similar to rice grown in other regions of Bangladesh. Importantly, it was found that the arsenic levels of aromatic rice (mean 48.5 µg/kg) from Sylhet region was over 40% lower than that of non-aromatic rice (mean 81 µg/kg). The aromatic rice also contained higher levels of essential elements (such as Se and Zn). It was calculated that for an individual consuming 0.5 kg of rice per day, switching from consumption of non-aromatic rice to aromatic rice would increase Se and Zn intake by 46% and 23% respectively. Arsenic speciation was also carried out on other Bangladeshi food and non-food items, including fish, betel quid and baked clay, to obtain a better insight into exposure to toxic arsenic species. High levels of arsenic (range 3.8-13.1 mg/kg) and lead (range 21-26.7 mg/kg) were detected in the baked clay samples, which are consumed by some Bangladeshi women in an ancient practice known as geophagy. The efficiency of arsenic extraction from baked clay was 33% of the total arsenic present and the main arsenic species present was inorganic AsV (100%); AsIII was not detected in these samples. Millions of Bangladeshis chew betel quid and this contained predominantly AsIII species (extraction efficiency was 100%). Arsenic and lead intake from eating baked clay could exceed the provisional maximum tolerable daily intake (PMTDI) by 2- and 5-fold respectively. For the first time, arsenic speciation in Bangladeshi fish is reported. Hilsha, which is a very popular fish in Bangladesh, contained 2.55 mg/day (mean value) of total arsenic. Extraction efficiencies (%) were 59 – 89 for fish flesh, over 69% of arsenic present in the extract was dimethyl arsenic acid (DMA) species with about 11% arsenobetaine (AsBet) and 19% arsenosugar. These studies reveal that rice, betel quids and baked clay can be a significant source of exposure to inorganic arsenic and DMA in Bangladeshis. Exposure to cadmium is linked with kidney disease and over 20 million people in Bangladesh suffer from chronic kidney disease. Results obtained showed that the daily intake of cadmium by the Bangladeshi population from baked clay (mean 17 µg/day), rice (mean 18.6 µg/day) and certain leafy vegetables (mean 12 µg/day) was higher total daily intake compared to other countries. Surprisingly, puffed rice, which is commonly consumed by Bangladeshis, contained much higher levels of cadmium (mean 67.9 µg/kg) and lead (mean 98 µg/kg), compared to uncooked rice (cadmium, 37.2 µg/kg; lead, 18.9 µg/kg). This may be related to the illegal practice of using urea for whitening puffed rice in Bangladesh. Exposure to manganese in the Bangladeshi population through drinking water has been previously highlighted as a possible health problem, although the intake from foods and non-food has not been reported. The daily manganese intake by Bangladeshis was calculated to be 20.3 mg/day, which is higher than any other country in the world thus far reported. Betel quid components have high levels of manganese and this was reflected by higher urinary manganese the mean urinary Mn levels in chewers (1.93 µg/L, SD 1.8) was significantly higher (3.1 fold; P = 0.009) compared to non-chewers (0.62 µg/L, SD 0.4). Bangladeshi women who eat baked clay and chew betel quids are likely to be exposed to high levels of arsenic, lead and other toxic elements. This is particularly of concern for pregnant women as these metals can be transferred to the unborn baby through the placenta. For assessing the risk of exposure to toxic elements versus intake of essential elements from the same foods, a Food Toxicity Scale (FTS) was devised in order to identify foods that are beneficial or harmful. FTS values were obtained by calculating the toxic elements : essential elements ratio (As:Se, As:Zn etc) and the value obtained subsequently multiplied by toxic element concentration and the quantity of the particular food consumed per day. The higher the FTS value, the greater the risk of exposure to harmful elements. Rice and leafy vegetables had the highest FTS values, partly because large quantities of these foods are consumed. However, lentils and animal products (such as small fish) had relatively lower FTS values compared to other foods. Total daily intake of arsenic (306 µg/day), selenium (90.4 µg/day), cadmium (34.6 µg/day), lead (74.4 µg/day), manganese (20.3 mg/day) and zinc (11.2 mg/day) in the Bangladeshi population was calculated. The intake of arsenic and manganese exceeds the PMTDI for these elements. Water was the highest source of arsenic exposure in Bangladeshis followed by rice. For cadmium and lead, rice and leafy vegetables were the key contributors to the daily intake. The results presented in this thesis show that Bangladeshis are exposed to high levels of toxic elements and how modifications can be made to their diet to not only reduce their exposure to toxic elements but also increase the intake of essential elements. This could be achieved by a combination of the following: (i) reducing the intake of rice (by about 50%); (ii) switching to eating aromatic rice; (iii) increasing the intake of animal products (meat, fish etc.); (iv) decreasing the intake of certain leafy vegetables; and (v) stopping or reducing the practice of eating baked clay and chewing betel quid.

O uso combinado das tecnologias de micro-ondas e infravermelho, para aquecimento e reaquecimento de produtos prontos, pode ser considerado uma nova e eficiente técnica de preparo de alimentos, já que o processo de cozimento é otimizado e melhor controlado, pois altos fluxos de calor são transferidos para a superfície do alimento, com controle quase que instantâneo da energia fornecida. Dentro desse contexto, o objetivo deste trabalho foi desenvolver e testar uma nova forma de reaquecimento de produtos assados, por meio da combinação de micro-ondas e infravermelho em forno tipo túnel. Simulações computacionais e testes preliminares foram realizados em ambientes nos quais pode-se controlar, tanto as emissões da radiação infravermelha quanto a micro-ondas. Os testes foram realizados com salgados assados como forma de evidenciar a eficácia de ação de ambas as tecnologias, levando-se em conta a complexidade das condições de contorno de tais alimentos, uma vez que os mesmos podem ser modelados como possuindo duas fases: uma cujas as propriedades são estabelecidas pela massa e a outra em que as propriedades são provenientes do recheio. Foram realizados estudos preliminares que permitiram verificar o comportamento de cada fase do alimento frente ao reaquecimento pelas duas radiações, o que forneceu os tempos de ação de 15 segundos de micro-ondas (protótipo modelo), mais 30 segundos de infravermelho no forno tipo túnel. Com a metodologia desenvolvida foi possível medir com eficiência a temperatura interna e externa das amostras, bem como a migração de umidade do centro para a superfície, permitindo concluir que a ação de ambas as radiações foi eficiente no reaqueciamento dos alimentos no forno tipo túnel estudado. / The combined use of microwave and infrared technologies for heating and reheating of fast-food may be considered a new and efficient technique for food preparation, due the fact that baking process is optimized and controlled, such technology have high heat flows transferring to the food surface instantaneous energy. In this context, the aim of this study was to develop and test a new way of heating baked foods, through a combination of microwave and infrared oven type tunnel. Computer simulation and preliminary tests were carried out in environments in which one can control both the emission of infrared radiation as a microwave. The tests were conducted with baked foods in order to show the effectiveness and action of both technologies, taking into account the complexity of such foods boundary conditions, they can be modelled as having two phases: one whose the properties are set by the dough properties and the other where the properties of components bounded by dough.Preliminary studies was carried out to verify the effect of both radiations in each food phase which provided the action times of 15 seconds of microwave (prototype model) 30 seconds infrared oven tunnel type. With this methodology was ble the measurement of internal and external temperature of the samples, as well as moisture migration from the center to the surface. The results showed that the action of both radiation was effective in rehating biphasic food.

O uso combinado das tecnologias de micro-ondas e infravermelho, para aquecimento e reaquecimento de produtos prontos, pode ser considerado uma nova e eficiente técnica de preparo de alimentos, já que o processo de cozimento é otimizado e melhor controlado, pois altos fluxos de calor são transferidos para a superfície do alimento, com controle quase que instantâneo da energia fornecida. Dentro desse contexto, o objetivo deste trabalho foi desenvolver e testar uma nova forma de reaquecimento de produtos assados, por meio da combinação de micro-ondas e infravermelho em forno tipo túnel. Simulações computacionais e testes preliminares foram realizados em ambientes nos quais pode-se controlar, tanto as emissões da radiação infravermelha quanto a micro-ondas. Os testes foram realizados com salgados assados como forma de evidenciar a eficácia de ação de ambas as tecnologias, levando-se em conta a complexidade das condições de contorno de tais alimentos, uma vez que os mesmos podem ser modelados como possuindo duas fases: uma cujas as propriedades são estabelecidas pela massa e a outra em que as propriedades são provenientes do recheio. Foram realizados estudos preliminares que permitiram verificar o comportamento de cada fase do alimento frente ao reaquecimento pelas duas radiações, o que forneceu os tempos de ação de 15 segundos de micro-ondas (protótipo modelo), mais 30 segundos de infravermelho no forno tipo túnel. Com a metodologia desenvolvida foi possível medir com eficiência a temperatura interna e externa das amostras, bem como a migração de umidade do centro para a superfície, permitindo concluir que a ação de ambas as radiações foi eficiente no reaqueciamento dos alimentos no forno tipo túnel estudado. / The combined use of microwave and infrared technologies for heating and reheating of fast-food may be considered a new and efficient technique for food preparation, due the fact that baking process is optimized and controlled, such technology have high heat flows transferring to the food surface instantaneous energy. In this context, the aim of this study was to develop and test a new way of heating baked foods, through a combination of microwave and infrared oven type tunnel. Computer simulation and preliminary tests were carried out in environments in which one can control both the emission of infrared radiation as a microwave. The tests were conducted with baked foods in order to show the effectiveness and action of both technologies, taking into account the complexity of such foods boundary conditions, they can be modelled as having two phases: one whose the properties are set by the dough properties and the other where the properties of components bounded by dough.Preliminary studies was carried out to verify the effect of both radiations in each food phase which provided the action times of 15 seconds of microwave (prototype model) 30 seconds infrared oven tunnel type. With this methodology was ble the measurement of internal and external temperature of the samples, as well as moisture migration from the center to the surface. The results showed that the action of both radiation was effective in rehating biphasic food.

Pães são produtos assados, obtidos da farinha de trigo e ou outras farinhas. É um produto popular consumido na forma de lanches, acompanhando refeições, apreciado pela sua aparência, aroma, sabor, variedade, preço e disponibilidade. Este trabalho trata do mercado atual de panificação e a necessidade do desenvolvimento de novos produtos, através de processos alternativos de produção. São propostos métodos de fermentação mista com kefir, processo de fermentação com esponja e escaldamento de cereais. Os ensaios foram conduzidos através de delineamentos experimentais específicos, utilizando a metodologia por superfície de resposta. A partir dos resultados obtidos pôde-se confirmar a viabilidade de produzir-se amostras com propriedades mecânicas e sensoriais diferenciadas das atualmente existentes. / Bread is a popular product consumed as a sandwich or during mealtime and appreciated by its appearance, flavor, taste, price, and availability. This work deals with the current market of bakery products and the necessity of the development of new products and the necessity of the development of new products, through alternative production processes. Methods of fermentation using kefir, fermentation sponge process, and cereals scalding were considered. The experiments had been lead through specific experimental design, using the surface response methodology. From the obtained results could be confirmed the viability to produce samples with differentiated mechanical and sensory properties of the currently existing ones.

Pães são produtos assados, obtidos da farinha de trigo e ou outras farinhas. É um produto popular consumido na forma de lanches, acompanhando refeições, apreciado pela sua aparência, aroma, sabor, variedade, preço e disponibilidade. Este trabalho trata do mercado atual de panificação e a necessidade do desenvolvimento de novos produtos, através de processos alternativos de produção. São propostos métodos de fermentação mista com kefir, processo de fermentação com esponja e escaldamento de cereais. Os ensaios foram conduzidos através de delineamentos experimentais específicos, utilizando a metodologia por superfície de resposta. A partir dos resultados obtidos pôde-se confirmar a viabilidade de produzir-se amostras com propriedades mecânicas e sensoriais diferenciadas das atualmente existentes. / Bread is a popular product consumed as a sandwich or during mealtime and appreciated by its appearance, flavor, taste, price, and availability. This work deals with the current market of bakery products and the necessity of the development of new products and the necessity of the development of new products, through alternative production processes. Methods of fermentation using kefir, fermentation sponge process, and cereals scalding were considered. The experiments had been lead through specific experimental design, using the surface response methodology. From the obtained results could be confirmed the viability to produce samples with differentiated mechanical and sensory properties of the currently existing ones.

Orientador: Yoon Kil Chang / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-17T11:54:19Z (GMT). No. of bitstreams: 1 Almeida_EvelineLopes_D.pdf: 15986514 bytes, checksum: 094dacc9b30033f34ea8b0f9287a156e (MD5) Previous issue date: 2011 / Resumo: Existe evidência da relação entre o consumo de cereais integrais e a prevenção do desenvolvimento de várias doenças como alguns tipos de câncer, doenças cardiovasculares, diabete e obesidade. O mercado de pães pré-assados congelados está em ascensão, fazendo deste produto um excelente alimento para veiculação do cereal integral. O objetivo deste trabalho foi avaliar a qualidade de pão francês pré-assado congelado elaborado com farinha do trigo integral através do estudo do efeito do tempo de fermentação, do efeito da adição de enzimas, da influência do período de estocagem congelada e das transformações da massa nas etapas de pré-assamento e reassamento. Na primeira parte várias formulações foram avaliadas em dois tempos de fermentação diferentes. Na segunda parte um delineamento composto central rotacional (DCCR) foi realizado com as enzimas glicolipase, hemicelulase e hexose-oxidase como as variáveis independentes. Na terceira parte, os pães pré-assados congelados foram estocados por 0, 1, 7, 15, 30 e 65 dias congelados para avaliação destes períodos. Características como volume específico, textura (firmeza e elasticidade), salto de forno, formato, abertura e pestana foram avaliados nestas três partes. Na terceira parte, a transição térmica do amido, fração de água congelada e avaliação sensorial também foram realizadas. Na quarta parte, características como perfil de temperatura do processo, umidade, cor, comportamento viscoamilográfico, transição térmica do amido, difratometria dos raios-x, microscopia óptica de luz polarizada e microscopia eletrônica de varredura foram avaliadas no final das etapas de pré-assamento e reassamento em três porções dos pães (miolo interno, miolo externo e crosta). Os resultados mostraram que é possível produzir pão francês préassado congelado elaborado com farinha do trigo integral, sendo fonte de fibras pela legislação brasileira (mínimo de 3 g de fibra alimentar / 100 g de produto pronto para consumo), que possua atributos de qualidade aceitáveis ao consumidor que relatou alta intenção de compra do produto. Para alcançar tal objetivo, o tempo de fermentação deve ser otimizado de acordo com a formulação para que não ocorra colapso da estrutura. As enzimas glicolipase, hemicelulase e hexose oxidase devem ser utilizadas nas faixas de 30-75 ppm, 91- 359 ppm e 30-120 ppm (base farinha), respectivamente, conjuntamente com uma formulação base. O pão pode ser mantido por 65 dias sob estocagem congelada sem que o consumidor perceba alterações nos atributos do pão (aparência, volume, formato, cor, avaliação global) e da fatia (cor, aroma, sabor, textura, avaliação global). A umidade e a cor apresentadas pelos pães após as etapas de pré-assamento e reassamento mostraram que eles apresentavam boas características para a sua comercialização / Abstract: There is evidence of the relationship between the consumption of whole grains and the prevention of illnesses such as cancer, cardiovascular disease, diabetes and obesity. The market of frozen part-baked breads is in ascension, making of this product an excellent food for the propagation of whole grains. The aim of this work was to evaluate the quality of frozen part-baked French bread made with whole wheat flour through the study of (01) effect of proofing time; (02) effect of the addition of enzymes; (03) influence of time of frozen storage and (04) changes of dough during the steps of partbaking and rebaking. In the first part, several formulations were evaluated at two different proofing times. In the second part, a central composite rotational design (CCRD) was used, with the percentages of glycolipase, xylanase and hexose oxidase being the independent variables. In the third part, frozen part-baked breads were frozen stored for 0, 1, 7, 15, 30 and 65 days for the evaluation of these periods. Characteristics such as specific volume, crumb texture (firmness and springiness), oven spring, shape, measurement of the opening and cut of surface were evaluated in these three parts. In the third part, the thermal transition of starch, the unfreezable water fraction and sensory tests were also carried out. In the fourth part, characteristics such as temperature profile, moisture, color, pasting properties, thermal transitions of starch, x-ray crystallography, Fourier infra-red spectroscopy, polarized light microscopy and scanning electron microscopy were evaluated at the end of the part-baking and rebaking steps in three portions of the breads (inner crumb, outer crumb and crust). The results showed that it is possible to elaborate frozen part-baked French bread made with whole wheat flour, source of fiber by the Brazilian legislation (at least 3 g dietary fiber / 100 g final product), that has acceptable quality attributes to the consumer who related high purchase intention of the product. To reach such objective, the proofing time should be optimized in accordance with the formulation to avoid the collapse of the structure. The enzymes glycolipase, xylanase and hexose oxidase should be employed within the ranges of 30-75 ppm, 91-359 ppm and 30- 120 ppm (flour basis), respectively, together with a basic formulation. The bread can be kept for 65 days under frozen storage without the consumer noting changes in bread attributes (appearance, volume, shape, color, global evaluation) and slice attributtes (color, flavor, taste, texture, global evaluation). The moisture and the color presented by breads after the stages of part-baking and rebaking showed that they showed good characteristics for its commercialization / Doutorado / Engenharia de Alimentos / Doutor em Tecnologia de Alimentos

<p>Low moisture baked goods (cookies, biscuits, etc.) are known for their high sugar content, low water content, and characteristic texture. The added sugar in baked goods has been a concern of health advocates due to the negative health implications of overconsumption of sugar. To minimize these health implications and support healthier food products, the replacement of sugar, sucrose, in low moisture baked goods with alternative sweeteners is of interest. The goal of this study was to improve understanding on how sweetener alternatives and dietary fiber interact with cookie ingredients and the subsequent cookie texture compared to sucrose containing cookies to aid in developing health-conscious low moisture baked goods.</p><p> The replacement of sucrose with sucrose replacers (SRs) encompassing a variety of structural and physicochemical properties (high fructose corn syrup (HFCS), amorphous sucrose, maltitol, allulose, isomalt, Benefiber, Miralax, fructooligosaccharides (FOS), and isomalto-oligosacchrides (IMO)) in wire-cut cookies was investigated in terms of starch thermal properties, model cookie formulations, and sensory descriptive analysis. Starch thermal properties were investigated using differential scanning calorimetry (DSC) while wire-cut cookie parameters were analyzed through a_w, color (<i>a, b, L</i>), moisture loss, cookie dimensions (height, width, length), and cookie hardness (N) assays. Sensory descriptive analysis was used to ascertain texture perception of wire-cut cookies through five attributes (hardness, fracturability, pastiness, cohesiveness, and crumbliness).</p> The onset gelatinization temperature (T_gel) was increased to a greater extent than sucrose by Miralax and FOS, and to the same extent by IMO, maltitol, and Benefiber at high concentrations (60%w/w). The SRs which performed similar to sucrose in wire-cut cookie baking (spread, moisture loss, hardness) and texture intensity ratings were amorphous sucrose, maltitol, and allulose. No significant differences in descriptive analysis intensity scores were found in crumbliness, cohesiveness, and pastiness between SRs and sucrose formulated wire-cut cookies. FOS, IMO, and Benefiber displayed significantly larger fracture intensity scores compared so sucrose and isomalt cookies were significantly less hard than sucrose cookies. Principal component analysis (PCA) related SRs effect on starch gelatinization, cookie baking properties, and descriptive analysis intensity scores, and indicated the mostly likely candidates for use in reduced sugar cookies are maltitol and allulose.

Comparative performance of the electronic, conventional, and combination (electronic and conventional) ovens was studied in the preparation of five typical foods: baked custard, lemon cake, baked potatoes, orange marmalade tea loaf, and roast chicken. The data collected included final temperature of each food and ratings of each food by a taste panel. Foods prepared electronically and by the combination method required significantly less time with the exception of lemon cake. Foods prepared by the combination and conventional methods were preferred by the taste panel over foods prepared electronically with the exception of custard which was rated superior to custard cooked conventionally.

No description available.