Thesis (M.S.)--Humboldt State University, 2006. / In pocket: Wilderness food storage survey, Yosemite National Park, 2005 ([10] p. ; 22 cm.). Includes bibliographical references (leaves 54-60). Also available via Humboldt Digital Scholar.

Thesis (Masters Diploma (Food Technology)) -- Cape Technikon, Cape Town, 1992 / Kakamas peaches and Bulida apricots were heat processed in transparent and aluminium laminated plastic bags and compared with fruit heat processed in standard cans. Heat processing conditions were optimized to produce acceptable processed products. Appropriate chemical and microbiological properties of all treatments as well as sensory quality of peaches were investigated. Although rectifiable disadvantages such as texture softening and fading of colour appeared during storage, peaches and apricots were successfully heat processed in aluminium laminated pouches. Heat processed peaches had a maximum storage life of 12 months and apricots 6 months when stored at ambient temperature in aluminium laminated pouches.

Five formula methods and three numerical general methods for determining thermal process lethality were compared with a reference method to demonstrate their applicability to conduction heating foods in cylindrical containers. Hypothetical centerpoint temperature history curves for cans with height to diameter (H/D) ratios of 0.1 to 3.0 were generated for a range of processing conditions using computer simulation. A finite-difference model based on Teixeira et al. (1969b) was used as the basis of the simulation program. The delivered lethality to an organism characterized by Z=10C° was evaluated using each of the methods and compared to the lethality calculated using the reference method. For each of the test methods, simulation data were provided for one minute intervals, but for the reference method, data were provided for intervals of 0.05 min. Each of the selected formula methods was adapted to allow calculations to be done by computer without operator intervention. The most significant part of this adaptation was the development of a system that enabled the computer to select the linear portion of the heat penetration curve to facilitate calculation of the parameters f and j which are required by all of the formula methods. A method for handling large tables was also developed for use with some of the formula methods. For the general methods, the deviations from the reference method were greatest when the heating rate index (fh) and H/D were small and the unaccomplished temperature difference (g) was large. Whereas the the value of fh was the most significant factor affecting the accuracy of calculations done using the general method, it did not greatly affect the performance of the formula methods. The factors that most significantly influenced deviations between the formula methods and the reference method were H/D and g. The largest deviations in all cases occurred when g was large and H/D was close to unity. These errors were mostly on the "safe" side, but the energy use implications could be significant, especially for high retort temperature processes. / Land and Food Systems, Faculty of / Graduate

O porongo (Lagenaria siceraria) é o fruto de uma planta da família das cucurbitáceas que quando colhido, se deixado secar, torna-se oco com o mesocarpo similar ao aspecto da madeira e o exocarpo liso e impermeável. Este fruto disseminou-se por todos os continentes antes do homem e foi uma das primeiras plantas domesticadas. Diferentes povos utilizam o porongo na confecção de recipientes, instrumentos musicais, boias e máscaras. No sul do Brasil é empregado na fabricação das cuias, recipientes para o chimarrão. Planta de hábito tropical, adapta-se facilmente à qualquer clima, com ciclo produtivo anual configura-se em alternativa de fonte renovável. Como material natural orgânico, é suscetível à degradação sem tratamento. Buscando viabilizar sua utilização na fabricação de recipientes para alimentos e bebidas priorizou-se a caracterização da estrutura e a aplicação de técnicas de impermeabilização. Para a confecção da amostras foram utilizados frutos coletados em Santa Maria, RS, e para a impermeabilização foi utilizada resina poliuretana à base de óleo de mamona. A caracterização do material constituinte do porongo foi feita com auxílio de microscópio eletrônico de varredura, microscopio de luz transmitida, análise termogravimétrica, determinação do teor de umidade, da densidade básica e da aparente e através da digitalização tridimensional para análise da variação dimensional. A caracterização da resina foi feita por espectroscopia de infra-vermelho com transformada de Fourier e a eficiência da impermeabilização foi analisada através de ensaio de absorção de água e ângulo de contato de gota. Pela microscopia identificou-se o exocarpo como uma fina camada de células compactas, por isso impermeável, e o mesocarpo formado pelo parênquima, com células que aumentam de tamanho progressivamente em direção ao centro, caracterizadas por grandes espaços vazios com parede espessada lignificada e canais de comunicação intercelular, que faz o material ser altamente hidrofílico. Ao absorver a água, há o preenchimento dos vácuolos das células até a saturação, sem grandes alteraçãos das dimensões do material, dimensionalmente estável. O porongo possui densidade heterogênea muito baixa, em média 0,124 g/cm³, na faixa de densidade das espumas poliméricas. Quanto à absorção de água, as amostras sem tratamento tiveram aumento de massa de cerca de 150% até a saturação. Após a impermeabilização, as amostras com uma camada de resina tiveram aumento de massa entre 23% e 37%, enquanto que àquelas com duas camadas de resina de apenas 5% e 6%, o que indica a eficiência do método de impermeabilização. / The bottle gourd (Lagenaria siceraria) is the fruit of the Cucurbitaceae family plant which when harvested, if allowed to dry, becomes hollow with the mesocarp similar to the appearance of the wood and with a smooth and impermeable exocarp. This fruit has spread to all continents before man and was one of the first domesticated plants. Different people use the gourd in the manufacture of containers, musical instruments, floats and masks. In southern Brazil it is used to manufacture the bowls, containers for mate. Tropical habit plant, easily adapts to any climate, with annual production cycle sets itself as renewable source alternative. As an organic natural material, it is susceptible to degradation without treatment. Seeking to enable its use in the manufacture of containers for food and beverages it has prioritized the characterization of the structure and the application of waterproofing techniques. Seeking allow its use in the manufacture of containers for food and beverages prioritized the characterization of the structure and the application of waterproofing techniques. To prepare the samples were used fruits collected in Santa Maria, RS, and for waterproofing was used polyurethane resin on castor oil base. The characterization of the material which constitutes porongo was made thorugh electron microscope scanning, transmitted light microscope, thermal analysis, determination of moisture content, basic and apparent density and by three-dimensional scanning to analyze the dimensional variation. The characterization of resin was made by infrared spectroscopy with Fourier transform and the efficiency of the waterproofing was analyzed by water absorption and drop contact angle test. Microscopy enabled to identify the exocarp as a thin layer of compact cells, thus waterproof, and the mesocarp formed by parenchyma with cells that progressively increase in size towards the center, characterized by large empty spaces with thickened and lignified wall and intercellular communication channels, which makes the material be highly hydrophilic. By absorbing the water, there is filling in the vacuoles of the cells until the saturation without large re-arranging of the material dimensions, dimensionally stable. The gourd has very poor heterogeneous density, on average 0.124 g / cm³, in the density range of polymeric foams. Regarding to water-absorbing, untreated samples had mass increase of about 150% until saturation. After sealing, the samples with a resin layer had increased mass between 23% and 37%, while those with two resin layers only had increased mass from 5% to 6%, which indicates the sealing method efficiency.

O porongo (Lagenaria siceraria) é o fruto de uma planta da família das cucurbitáceas que quando colhido, se deixado secar, torna-se oco com o mesocarpo similar ao aspecto da madeira e o exocarpo liso e impermeável. Este fruto disseminou-se por todos os continentes antes do homem e foi uma das primeiras plantas domesticadas. Diferentes povos utilizam o porongo na confecção de recipientes, instrumentos musicais, boias e máscaras. No sul do Brasil é empregado na fabricação das cuias, recipientes para o chimarrão. Planta de hábito tropical, adapta-se facilmente à qualquer clima, com ciclo produtivo anual configura-se em alternativa de fonte renovável. Como material natural orgânico, é suscetível à degradação sem tratamento. Buscando viabilizar sua utilização na fabricação de recipientes para alimentos e bebidas priorizou-se a caracterização da estrutura e a aplicação de técnicas de impermeabilização. Para a confecção da amostras foram utilizados frutos coletados em Santa Maria, RS, e para a impermeabilização foi utilizada resina poliuretana à base de óleo de mamona. A caracterização do material constituinte do porongo foi feita com auxílio de microscópio eletrônico de varredura, microscopio de luz transmitida, análise termogravimétrica, determinação do teor de umidade, da densidade básica e da aparente e através da digitalização tridimensional para análise da variação dimensional. A caracterização da resina foi feita por espectroscopia de infra-vermelho com transformada de Fourier e a eficiência da impermeabilização foi analisada através de ensaio de absorção de água e ângulo de contato de gota. Pela microscopia identificou-se o exocarpo como uma fina camada de células compactas, por isso impermeável, e o mesocarpo formado pelo parênquima, com células que aumentam de tamanho progressivamente em direção ao centro, caracterizadas por grandes espaços vazios com parede espessada lignificada e canais de comunicação intercelular, que faz o material ser altamente hidrofílico. Ao absorver a água, há o preenchimento dos vácuolos das células até a saturação, sem grandes alteraçãos das dimensões do material, dimensionalmente estável. O porongo possui densidade heterogênea muito baixa, em média 0,124 g/cm³, na faixa de densidade das espumas poliméricas. Quanto à absorção de água, as amostras sem tratamento tiveram aumento de massa de cerca de 150% até a saturação. Após a impermeabilização, as amostras com uma camada de resina tiveram aumento de massa entre 23% e 37%, enquanto que àquelas com duas camadas de resina de apenas 5% e 6%, o que indica a eficiência do método de impermeabilização. / The bottle gourd (Lagenaria siceraria) is the fruit of the Cucurbitaceae family plant which when harvested, if allowed to dry, becomes hollow with the mesocarp similar to the appearance of the wood and with a smooth and impermeable exocarp. This fruit has spread to all continents before man and was one of the first domesticated plants. Different people use the gourd in the manufacture of containers, musical instruments, floats and masks. In southern Brazil it is used to manufacture the bowls, containers for mate. Tropical habit plant, easily adapts to any climate, with annual production cycle sets itself as renewable source alternative. As an organic natural material, it is susceptible to degradation without treatment. Seeking to enable its use in the manufacture of containers for food and beverages it has prioritized the characterization of the structure and the application of waterproofing techniques. Seeking allow its use in the manufacture of containers for food and beverages prioritized the characterization of the structure and the application of waterproofing techniques. To prepare the samples were used fruits collected in Santa Maria, RS, and for waterproofing was used polyurethane resin on castor oil base. The characterization of the material which constitutes porongo was made thorugh electron microscope scanning, transmitted light microscope, thermal analysis, determination of moisture content, basic and apparent density and by three-dimensional scanning to analyze the dimensional variation. The characterization of resin was made by infrared spectroscopy with Fourier transform and the efficiency of the waterproofing was analyzed by water absorption and drop contact angle test. Microscopy enabled to identify the exocarp as a thin layer of compact cells, thus waterproof, and the mesocarp formed by parenchyma with cells that progressively increase in size towards the center, characterized by large empty spaces with thickened and lignified wall and intercellular communication channels, which makes the material be highly hydrophilic. By absorbing the water, there is filling in the vacuoles of the cells until the saturation without large re-arranging of the material dimensions, dimensionally stable. The gourd has very poor heterogeneous density, on average 0.124 g / cm³, in the density range of polymeric foams. Regarding to water-absorbing, untreated samples had mass increase of about 150% until saturation. After sealing, the samples with a resin layer had increased mass between 23% and 37%, while those with two resin layers only had increased mass from 5% to 6%, which indicates the sealing method efficiency.

O porongo (Lagenaria siceraria) é o fruto de uma planta da família das cucurbitáceas que quando colhido, se deixado secar, torna-se oco com o mesocarpo similar ao aspecto da madeira e o exocarpo liso e impermeável. Este fruto disseminou-se por todos os continentes antes do homem e foi uma das primeiras plantas domesticadas. Diferentes povos utilizam o porongo na confecção de recipientes, instrumentos musicais, boias e máscaras. No sul do Brasil é empregado na fabricação das cuias, recipientes para o chimarrão. Planta de hábito tropical, adapta-se facilmente à qualquer clima, com ciclo produtivo anual configura-se em alternativa de fonte renovável. Como material natural orgânico, é suscetível à degradação sem tratamento. Buscando viabilizar sua utilização na fabricação de recipientes para alimentos e bebidas priorizou-se a caracterização da estrutura e a aplicação de técnicas de impermeabilização. Para a confecção da amostras foram utilizados frutos coletados em Santa Maria, RS, e para a impermeabilização foi utilizada resina poliuretana à base de óleo de mamona. A caracterização do material constituinte do porongo foi feita com auxílio de microscópio eletrônico de varredura, microscopio de luz transmitida, análise termogravimétrica, determinação do teor de umidade, da densidade básica e da aparente e através da digitalização tridimensional para análise da variação dimensional. A caracterização da resina foi feita por espectroscopia de infra-vermelho com transformada de Fourier e a eficiência da impermeabilização foi analisada através de ensaio de absorção de água e ângulo de contato de gota. Pela microscopia identificou-se o exocarpo como uma fina camada de células compactas, por isso impermeável, e o mesocarpo formado pelo parênquima, com células que aumentam de tamanho progressivamente em direção ao centro, caracterizadas por grandes espaços vazios com parede espessada lignificada e canais de comunicação intercelular, que faz o material ser altamente hidrofílico. Ao absorver a água, há o preenchimento dos vácuolos das células até a saturação, sem grandes alteraçãos das dimensões do material, dimensionalmente estável. O porongo possui densidade heterogênea muito baixa, em média 0,124 g/cm³, na faixa de densidade das espumas poliméricas. Quanto à absorção de água, as amostras sem tratamento tiveram aumento de massa de cerca de 150% até a saturação. Após a impermeabilização, as amostras com uma camada de resina tiveram aumento de massa entre 23% e 37%, enquanto que àquelas com duas camadas de resina de apenas 5% e 6%, o que indica a eficiência do método de impermeabilização. / The bottle gourd (Lagenaria siceraria) is the fruit of the Cucurbitaceae family plant which when harvested, if allowed to dry, becomes hollow with the mesocarp similar to the appearance of the wood and with a smooth and impermeable exocarp. This fruit has spread to all continents before man and was one of the first domesticated plants. Different people use the gourd in the manufacture of containers, musical instruments, floats and masks. In southern Brazil it is used to manufacture the bowls, containers for mate. Tropical habit plant, easily adapts to any climate, with annual production cycle sets itself as renewable source alternative. As an organic natural material, it is susceptible to degradation without treatment. Seeking to enable its use in the manufacture of containers for food and beverages it has prioritized the characterization of the structure and the application of waterproofing techniques. Seeking allow its use in the manufacture of containers for food and beverages prioritized the characterization of the structure and the application of waterproofing techniques. To prepare the samples were used fruits collected in Santa Maria, RS, and for waterproofing was used polyurethane resin on castor oil base. The characterization of the material which constitutes porongo was made thorugh electron microscope scanning, transmitted light microscope, thermal analysis, determination of moisture content, basic and apparent density and by three-dimensional scanning to analyze the dimensional variation. The characterization of resin was made by infrared spectroscopy with Fourier transform and the efficiency of the waterproofing was analyzed by water absorption and drop contact angle test. Microscopy enabled to identify the exocarp as a thin layer of compact cells, thus waterproof, and the mesocarp formed by parenchyma with cells that progressively increase in size towards the center, characterized by large empty spaces with thickened and lignified wall and intercellular communication channels, which makes the material be highly hydrophilic. By absorbing the water, there is filling in the vacuoles of the cells until the saturation without large re-arranging of the material dimensions, dimensionally stable. The gourd has very poor heterogeneous density, on average 0.124 g / cm³, in the density range of polymeric foams. Regarding to water-absorbing, untreated samples had mass increase of about 150% until saturation. After sealing, the samples with a resin layer had increased mass between 23% and 37%, while those with two resin layers only had increased mass from 5% to 6%, which indicates the sealing method efficiency.

The object of this research was to develop a retort for research and development of thermal processes which use common commercial thermal processing techniques. An FMC 500W laboratory sterilizer, designed to operate with an FMC weir product racking system, was modified for conventional steam, positive flow steam/air and water immersion/air overpressure thermal processing of foods in thin profile retortable packages. The research included the modification of the retort plumbing and the fabrication of a set of product trays and a racking system. The completed system was tested for temperature distribution and stability, and heat transfer distribution for each processing mode. The latter was achieved by comparing the heat penetration parameters calculated from the centerpoint temperature histories of conduction heating teflon transducers. / Applied Science, Faculty of / Graduate

In this paper the parametric design and functional optimisation of thin-walled structures made from plastics for food packaging is considered. These objects are produced in such vast numbers each year that one important task in the design of these objects is to minimise the amount of plastic used, subject to functional constraints, to reduce the costs of production and to conserve raw materials. By means of performing an automated optimisation on the possible shapes of the food containers, where the geometry is parametrised succinctly, a strategy to create the optimal design of the containers subject to a given set of functional constraints is demonstrated.

Phthalate esters (PEs) belong to a class of organic compounds used as plasticisers in plastic materials such as polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET) and so on, including those used in the food packaging industry. Phthalate plasticisers are not chemically bound to plastic materials and hence, migrate into items such as foodstuffs they house. The study aimed at investigating the prevalence of selected phthalate esters from plastic wrappers into food as well as the presence of food and/or pathogenic microorganisms. Plastic-wrapped cheese, vienna sausages and polony samples purchased from commercial stores in the four regions of Pretoria (Tswane), South Africa, were analysed for the presence of plasticisers; di-2-ethylhexyl adipate (DEHA), di-n-butyl phthalate (DnBP), benzyl-butyl phthalate (BBP), di-butyl phthalate (DBP) and dimethyl phthalate (DMP). Soxhlet extraction using hexane with florisil column cleanup was carried out. Analysis of PEs was by Gas Chromatography-Flame Ionization Detection (GC-FID). Microbiological investigations were performed using standard methods. The concentrations of PEs detected in food samples ranged from below detection limit (bdl) to 4.7003 μg/kg. However, DBP, DMP and BBP were predominantly present with more PEs detected in cheese compared to polony and vienna. In polony samples, DBP levels ranged from 0.0412 to 0.611μg/kg, in cheese, ranged from 0.049 to 0.256 μg/kg and in vienna DBP ranged from 0.074 to 0.209 μg/kg. The phthalate DMP ranged from 0.072 to 4.700 μg/kg in cheese, 0.056 to 0.241 μg/kg in polony and 0.092 to 0.816 μg/kg in vienna. The DEHA detected in cheese and polony was 0.120 μg/kg and 0.075 μg/kg respectively and no DEHA was detected in vienna sausages. For microbiological analysis, the total microbial activity (TMA) ranged from 6.8 x 104 to 1.03 x 108 cfu/g; coliforms ranged from no growth to 2.62 x 106 cfu/g; yeast ranged from no growth to 1.49 x 107 cfu/g; and mould ranged from no growth to 9.2 x 104 cfu/g. The results revealed that microbial activity was high in each sample type but revealed the absence of pathogens. Results revealed incidences of PEs in foods wrapped or packaged in plastics, which gave cause for concern and showed the need for proper monitoring and inspection of the levels of organo-microbial entities in the South African food wrapped in plastic wrappers. / Environmental Sciences / M.Sc. (Environmental Science)

Phthalate esters (PEs) belong to a class of organic compounds used as plasticisers in plastic materials such as polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET) and so on, including those used in the food packaging industry. Phthalate plasticisers are not chemically bound to plastic materials and hence, migrate into items such as foodstuffs they house. The study aimed at investigating the prevalence of selected phthalate esters from plastic wrappers into food as well as the presence of food and/or pathogenic microorganisms. Plastic-wrapped cheese, vienna sausages and polony samples purchased from commercial stores in the four regions of Pretoria (Tswane), South Africa, were analysed for the presence of plasticisers; di-2-ethylhexyl adipate (DEHA), di-n-butyl phthalate (DnBP), benzyl-butyl phthalate (BBP), di-butyl phthalate (DBP) and dimethyl phthalate (DMP). Soxhlet extraction using hexane with florisil column cleanup was carried out. Analysis of PEs was by Gas Chromatography-Flame Ionization Detection (GC-FID). Microbiological investigations were performed using standard methods. The concentrations of PEs detected in food samples ranged from below detection limit (bdl) to 4.7003 μg/kg. However, DBP, DMP and BBP were predominantly present with more PEs detected in cheese compared to polony and vienna. In polony samples, DBP levels ranged from 0.0412 to 0.611μg/kg, in cheese, ranged from 0.049 to 0.256 μg/kg and in vienna DBP ranged from 0.074 to 0.209 μg/kg. The phthalate DMP ranged from 0.072 to 4.700 μg/kg in cheese, 0.056 to 0.241 μg/kg in polony and 0.092 to 0.816 μg/kg in vienna. The DEHA detected in cheese and polony was 0.120 μg/kg and 0.075 μg/kg respectively and no DEHA was detected in vienna sausages. For microbiological analysis, the total microbial activity (TMA) ranged from 6.8 x 104 to 1.03 x 108 cfu/g; coliforms ranged from no growth to 2.62 x 106 cfu/g; yeast ranged from no growth to 1.49 x 107 cfu/g; and mould ranged from no growth to 9.2 x 104 cfu/g. The results revealed that microbial activity was high in each sample type but revealed the absence of pathogens. Results revealed incidences of PEs in foods wrapped or packaged in plastics, which gave cause for concern and showed the need for proper monitoring and inspection of the levels of organo-microbial entities in the South African food wrapped in plastic wrappers. / Environmental Sciences / M.Sc. (Environmental Science)