The purpose was to find the adjustments needed to make acceptable pies, cookies and muffins baked in the electronic oven. The products were evaluated by a taste panel and by objective tests. The results of both tests supported each other. The best bottom pie crust had an extra tablespoon of liquid added to the pastry and was precooked before the filling was added. It was both flaky and tender. No leavening and one-fourth more liquid produced the most acceptable cookies. They were more like standard cookie in height, texture, moisture and tenderness. It was found that one-half the amount of egg and two tablespoons more liquid made the best muffins. No treatment of the muffins as used in this study resembled the standard, but were half way between a standard muffin and cake in their texture, flavor and appearance.

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.

No description available.

Microwave heating is an efficient way of heating compared to conventional industrial alternatives such as autoclaves, a type of pressure cooker commonly used for curing and sterilisation. One problem that limits the adoption of microwave ovens in industrial processes is uneven heating. This project aims to simplify industrial microwave oven development by constructing a simulation of microwave heating using the finite-difference time-domain (FDTD) method. This is a common accepted method for solving differential equations. Simulation tools can be used to efficiently create prototypes virtually which makes for a more efficient development process of customised microwave ovens.%The implementation is written in Python and uses Meep, an open source FDTD library for simulating electromagnetic fields. The end product produces a model of a physical system and simulates the interaction between microwaves and the target material. This interaction results in heating of the target material, which can be observed through an animated heat map. This heat map can then be compared to the video from a thermographic camera to determine the model's validity and accuracy. The results of this project confirms the validity of the approach but does not validate the accuracy of the simulation. The system requires further development in three areas: 2D simulations must be scaled to 3D, the simulations predictive ability must be validated and the simulated time span must be increased. / Mikrovågsugnar är ett effektivt alternativ till konventionella lösningar för industriell uppvärmning, såsom autoklaver. autoklaver är en form av ugn som värmer under ökat tryck, ungefär som en tryckkokare, och används främst för härdning och sterilisering. Ojämn uppvärmning är en av de problemen som begränsar användning av mikrovågsugnar i industrin idag. Detta projekt försöker underlätta utveckling av industriella mikrovågsugnar genom att konstruera en simulering av mikrovågsuppvärmning genom finite-difference time-domain (FDTD) metoden. Detta är en vanligt förekommande metod för att lösa differentialekvationer. Med hjälp av simuleringsverktyg så kan digitala prototyper lätt skapas och testas, detta i sin tur leder till en effektivare utvecklingsprocess av specialdesignade microvågsugnar. Implementationen är skriven i python och använder Meep, ett FDTD-bibliotek för att simulera elektromagnetiska fält, med öppen källkod. Slutprodukten är en modell av ett fysiskt system där interaktionen mellan det elektriska fältet och materialet simulerats. Denna interaktion leder till uppvärmning av materialet, detta kan sedan observeras genom en animerad värmekarta. Denna kan sedan jämföras med en video från en termografisk kamera för att bestämma modellens giltighet och precision. Resultaten av detta projekt visar ett giltigt tillvägagångssätt, men verifierar inte giltigheten och precisionen av simuleringen. Systemet kräver vidareutveckling inom tre områden: Tvådimensionella simuleringar bör vara tredimensionella, simuleringens prediktiva förmåga måste valideras, samt att tidsspannet som simuleras bör ökas.

Call number: LD2668 .T4 1986 D53 / Master of Science / Human Nutrition

O tratamento térmico sob baixa umidade (TTBU) induz modificações estruturais nos grânulos de amido, com conseqüente modificação de propriedades como a digestibilidade enzimática e as propriedades de pasta. O TTBU clássico é realizado em fornos convencionais a ar e é bastante moroso. Recentemente melhorias têm sido propostas ao método, visando satisfazer aos requerimentos práticos para a aplicação em escala industrial. A aplicação de microondas em diversos setores vem crescendo e tem como vantagens a economia de espaço e tempo, devido ao tipo e eficiência da energia. Assim, o objetivo deste trabalho foi avaliar o efeito do TTBU realizado em forno microondas sobre as propriedades estruturais e funcionais de amidos de batata-doce e de mandioquinha-salsa e compará-las com as propriedades desses mesmos amidos tratados pelo método convencional. Os amidos foram extraídos dessas tuberosas e submetidos à modificação física, nas umidades de 25 e 35%, em forno convencional (90ºC/16horas) e em microondas (35 a 90ºC/1 hora). Os amidos tratados foram avaliados quanto à composição macromolecular (amilose), aparência superficial do grânulo por microscopia eletrônica de varredura (MEV), cristalinidade (raio-x), digestibilidade enzimática ( -amilase pancreática de suíno), fator de expansão e propriedades de pasta (RVA). O TTBU não alterou a aparência superficial dos amidos ao microscópio. Após a modificação física, o teor de amilose do amido de batata-doce tratado no microondas não se diferenciou do amido natural, porém apresentou menor teor do que o amido tratado em forno em ambas as umidades. O amido de mandioquinha-salsa tratado em forno convencional permaneceu com o mesmo teor do amido natural, já o tratamento por microondas aumentou o teor de amilose. O TTBU aumentou a suscetibilidade enzimática dos grânulos, sendo o amido de batata-doce o mais suscetível à ação da enzima pelo tratamento em forno e o amido de mandioquinha-salsa pelo microondas. A umidade das amostras pareceu afetar mais que o tipo de tratamento térmico. Sob maior umidade, os amidos tiveram maior aumento da suscetibilidade enzimática. Embora tenham ocorrido alterações nos difratogramas de raio-x mais ou menos intensas em função dos tratamentos, os padrões de cristalinidade dos amidos de batata-doce (CB) e de mandioquinha-salsa (B) permaneceram inalterados após os tratamentos sob quaisquer das condições estudadas. Os grânulos de amido das tuberosas tratados por TTBU apresentaram redução do fator de expansão. A expansão foi menor no forno convencional do que no microondas. O tratamento térmico alterou as propriedades de pasta dos amidos, aumentando, de um modo geral, a temperatura de pasta, o tempo de pico, a viscosidade final e a tendência à retrogradação e diminuindo o pico de viscosidade e a quebra. As alterações conferidas pelo TTBU foram variáveis com o tipo de tratamento térmico, o teor de umidade e com a fonte de amido. Considerando que a qualidade de um amido é definida em função de sua finalidade de uso, pode-se optar dentre os tratamentos estudados, a intensidade de modificação desejada para o mesmo. / The heat moisture treatment (HMT) induces structural modifications on the granules of starch with consequent modification of properties such as the enzymatic digestibility as well as the paste properties. The classic HMT is run in air conventional ovens and is very slow. Recently improvements have been proposed to the method by aiming to satisfy the practical requirements for the application in industrial scale. The application of the microwave in several sectors has been growing and presents as advantages the economy of room and time due to the type and efficiency of the energy. In this way, the objective of this work has been to evaluate the effect of the HMT made in microwave on the structural and functional properties of the sweet potato and peruvian carrot starches and compare them to the properties of the same starches treated by the conventional method. The starches have been extracted from these tuberoses and when at 25 and 35% moisture, submitted to physical modification in conventional oven (90ºC/16 hours) and in microwave oven (35 to 90ºC/1 hours). The treated starches have been evaluated regarding their macromolecular (amylose), granules surface appearance by scanning electron microscope (SEM), crystallinity (xrays), enzymatic digestibility (porcine pancreatic -amyilase), swelling factor and paste properties (RVA). The HMT has not changed the surface appearance of the starched through microscope. After the physical modification, the amylose content of the sweet potato starch treated in microwave oven has not been different from the natural starch, however presented less content than the starch treated in microwave oven at both moistures. The peruvian carrot starch treated in conventional oven remained with the same content of the natural starch, but the treatment in microwave has increased the amylose content. The HMT has increased the granules enzymatic susceptibility; the sweet potato starch is the most susceptible to the action of the enzyme by the treatment in oven and the peruvian carrot starch by the microwave oven, The moisture of the samples seemed to affect more than the type of heat treatment. Under higher moisture, the starches has had highest increase to enzymatic susceptibility. Although more or less intense alterations in the x-rays diffractograms have occurred due to the treatments, the crystallinity patterns of the sweet potato (CB) and peruvian carrot (B) starches remained unchanged after the treatments under any of the studied conditions. The tuberoses granules starches treated by HMT have presented reduction on the sweeling factor. The sweeling has been lower in conventional oven than in microwaves. The heat treatment has changed the starches paste properties, in a general way, increasing the paste temperature, peak time, final viscosity and setback and decreasing the viscosity peak and breakdown. The alterations checked by the HMT have been variable according to the type of heat treatment, moisture content and source of starch. Considering that the quality of a starch is defined in conformity with its use purpose, it can be chosen the type of treatment among the studied ones and the intensity of desired modification for the starch.

O tratamento térmico sob baixa umidade (TTBU) induz modificações estruturais nos grânulos de amido, com conseqüente modificação de propriedades como a digestibilidade enzimática e as propriedades de pasta. O TTBU clássico é realizado em fornos convencionais a ar e é bastante moroso. Recentemente melhorias têm sido propostas ao método, visando satisfazer aos requerimentos práticos para a aplicação em escala industrial. A aplicação de microondas em diversos setores vem crescendo e tem como vantagens a economia de espaço e tempo, devido ao tipo e eficiência da energia. Assim, o objetivo deste trabalho foi avaliar o efeito do TTBU realizado em forno microondas sobre as propriedades estruturais e funcionais de amidos de batata-doce e de mandioquinha-salsa e compará-las com as propriedades desses mesmos amidos tratados pelo método convencional. Os amidos foram extraídos dessas tuberosas e submetidos à modificação física, nas umidades de 25 e 35%, em forno convencional (90ºC/16horas) e em microondas (35 a 90ºC/1 hora). Os amidos tratados foram avaliados quanto à composição macromolecular (amilose), aparência superficial do grânulo por microscopia eletrônica de varredura (MEV), cristalinidade (raio-x), digestibilidade enzimática ( -amilase pancreática de suíno), fator de expansão e propriedades de pasta (RVA). O TTBU não alterou a aparência superficial dos amidos ao microscópio. Após a modificação física, o teor de amilose do amido de batata-doce tratado no microondas não se diferenciou do amido natural, porém apresentou menor teor do que o amido tratado em forno em ambas as umidades. O amido de mandioquinha-salsa tratado em forno convencional permaneceu com o mesmo teor do amido natural, já o tratamento por microondas aumentou o teor de amilose. O TTBU aumentou a suscetibilidade enzimática dos grânulos, sendo o amido de batata-doce o mais suscetível à ação da enzima pelo tratamento em forno e o amido de mandioquinha-salsa pelo microondas. A umidade das amostras pareceu afetar mais que o tipo de tratamento térmico. Sob maior umidade, os amidos tiveram maior aumento da suscetibilidade enzimática. Embora tenham ocorrido alterações nos difratogramas de raio-x mais ou menos intensas em função dos tratamentos, os padrões de cristalinidade dos amidos de batata-doce (CB) e de mandioquinha-salsa (B) permaneceram inalterados após os tratamentos sob quaisquer das condições estudadas. Os grânulos de amido das tuberosas tratados por TTBU apresentaram redução do fator de expansão. A expansão foi menor no forno convencional do que no microondas. O tratamento térmico alterou as propriedades de pasta dos amidos, aumentando, de um modo geral, a temperatura de pasta, o tempo de pico, a viscosidade final e a tendência à retrogradação e diminuindo o pico de viscosidade e a quebra. As alterações conferidas pelo TTBU foram variáveis com o tipo de tratamento térmico, o teor de umidade e com a fonte de amido. Considerando que a qualidade de um amido é definida em função de sua finalidade de uso, pode-se optar dentre os tratamentos estudados, a intensidade de modificação desejada para o mesmo. / The heat moisture treatment (HMT) induces structural modifications on the granules of starch with consequent modification of properties such as the enzymatic digestibility as well as the paste properties. The classic HMT is run in air conventional ovens and is very slow. Recently improvements have been proposed to the method by aiming to satisfy the practical requirements for the application in industrial scale. The application of the microwave in several sectors has been growing and presents as advantages the economy of room and time due to the type and efficiency of the energy. In this way, the objective of this work has been to evaluate the effect of the HMT made in microwave on the structural and functional properties of the sweet potato and peruvian carrot starches and compare them to the properties of the same starches treated by the conventional method. The starches have been extracted from these tuberoses and when at 25 and 35% moisture, submitted to physical modification in conventional oven (90ºC/16 hours) and in microwave oven (35 to 90ºC/1 hours). The treated starches have been evaluated regarding their macromolecular (amylose), granules surface appearance by scanning electron microscope (SEM), crystallinity (xrays), enzymatic digestibility (porcine pancreatic -amyilase), swelling factor and paste properties (RVA). The HMT has not changed the surface appearance of the starched through microscope. After the physical modification, the amylose content of the sweet potato starch treated in microwave oven has not been different from the natural starch, however presented less content than the starch treated in microwave oven at both moistures. The peruvian carrot starch treated in conventional oven remained with the same content of the natural starch, but the treatment in microwave has increased the amylose content. The HMT has increased the granules enzymatic susceptibility; the sweet potato starch is the most susceptible to the action of the enzyme by the treatment in oven and the peruvian carrot starch by the microwave oven, The moisture of the samples seemed to affect more than the type of heat treatment. Under higher moisture, the starches has had highest increase to enzymatic susceptibility. Although more or less intense alterations in the x-rays diffractograms have occurred due to the treatments, the crystallinity patterns of the sweet potato (CB) and peruvian carrot (B) starches remained unchanged after the treatments under any of the studied conditions. The tuberoses granules starches treated by HMT have presented reduction on the sweeling factor. The sweeling has been lower in conventional oven than in microwaves. The heat treatment has changed the starches paste properties, in a general way, increasing the paste temperature, peak time, final viscosity and setback and decreasing the viscosity peak and breakdown. The alterations checked by the HMT have been variable according to the type of heat treatment, moisture content and source of starch. Considering that the quality of a starch is defined in conformity with its use purpose, it can be chosen the type of treatment among the studied ones and the intensity of desired modification for the starch.

The aim of this study is to design a mixer with appropriate parts for uniform treatment of the material in household microwave ovens which can not be achieved with the turntable. The designed mixer&rsquo / s performance was tested by the help of color and surface temperature values. In the design of the mixer primarily mixing in the vertical and radial directions were sought and for this purpose blades and wings for directing the material especially in these directions were present. The rotational motion of the mixer was provided by a shaft actuated by the motor of the turntable where the motor was replaced by a speed adjustable one. Couscous macaroni beads wetted with CoCl2 solution were dried for processing in the microwave oven. The initial color values of the samples were L*= 52.0&plusmn / 0.35, a*= 8.8&plusmn / 0.21 and b*= 14.1&plusmn / 0.11 . The studied parameters were microwave power level (10%, 40%, 67% and 100% ), processing time (60,90, 120 sec), speed of rotation of the mixer (5,10,15 rpm) , location (4up, 4bt, 6up, 6bt) for the cases of with and without the mixer. v The macaroni beads were well arranged in a mixing container and then put into the microwave oven for operation. Same parameters with coloring experiments were used for the surface temperature determination. After operation the container was photographed by an IR camera. Whether the designed mixer was present or not, average a* and b* values decreased while temperature increased . All these values were significantly affected by the time and power increase. The L* value became an insignificant parameter to decide for the performance Location of the particles in the container appeared as a significant parameter affecting the a*, b* and temperature values without the mixer whereas, with the use of the mixer it became an insignificant parameter indicating uniform energy distribution. Speed of rotation of the mixer was a significant parameter for both cases. However, the color values obtained did not show the same trend with mixer which it showed without mixer. It is concluded that the designed mixer is effective in providing homogeneity of the product by providing sufficient mixing in the container hence the particles can receive about equal energy. Keywords: Microwave oven, particulate solids, mixing, mixer design, testing performance, uniform treatment

At the beginning of the theoretical part the objects and tasks of the theses are defined. There are also described the teaching methods of project teaching at the primary schools. History of ceramics from all over the world from the Neolithic period is an integral part of the theoretical part. The forming techniques, modeling, glazing and burning techniques are described as well. In the practical part ten ceramics themes to the project teaching at the first grade of primary school are designed. There is a didactic documentation for teachers for each theme.