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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Levantamento da entomofauna e micobiota de grãos de Phaseolus vulgaris L. e Vigna unguiculata L. tratados pelo processo de irradiação / Study of entomofauna and mycobiota in grains of Phaseolus vulgares L. and Vigna unguiculata L. treated by gamma-irradiation process

Fabrício Caldeira Reis 12 June 2018 (has links)
No presente trabalho realizou-se o levantamento da entomofauna e fungos associados a grãos de P. vulgares e V. unguiculata comercializados na cidade de São Paulo, avaliou-se a presença de fungos no corpo dos artrópodes identificados nas amostras de P. vulgares L. e V. unguiculata L., avaliou-se a atividade de água das amostras e estudou-se os efeitos do processo de irradiação na desinfestação de artrópodes e na redução da carga fúngica em grãos de P. vulgares e V. unguiculata. As amostras foram coletadas no comércio varejista em diferentes regiões da cidade São Paulo/SP. Foi adquirido 1 kg de 11 diferentes variedades entre P. vulgares (Branco, Bolinha, Carioca, Jalo, Preto, Rajado, Rosinha, Roxo e Vermelho) e V. unguiculata (Fradinho, Corda). As amostras foram desinfetadas em hipoclorito de sódio (0,5 %), enxaguadas em água destilada e distribuídos 10 grãos por placa de Petri em duplicata, contendo agar Batata Dextrose. As placas foram incubadas por 5 dias na temperatura de 25 ± 1°C, em incubadora (B.O.D.). O mesmo procedimento de plaqueamento foi realizado para os insetos isolados das amostras. No irradiador multipropósito 60Co IPEN/CNEN/SP as amostras foram irradiadas com doses de 5 e 10 kGy e os insetos foram submetidos a doses crescentes de 0 a 3,4 kGy. Diversos gêneros fúngicos foram isolados independentemente da variedade analisada. Foi constatada presença de fungos associados a insetos em todas as amostras analisadas. A dose recomendada para letalidade imediata e simultânea nas espécies Callosobruchus maculatus, Acanthoscelides obtectus e Zabrotes subfasciatus foi de 3,0 kGy. As doses de 5 e 10 kGy são capazes de reduzir, porém não eliminam a carga fúngica dos feijões analisados. Os valores obtidos na análise de atividade de água (Aa) situaram-se abaixo do limite ideal para crescimento fúngico diretamente nos grãos. / In this study we evaluated the entomofauna and fungi associated with Phaseolus vulgares L. and Vigna unguiculata L. found in the market in São Paulo city, measured the presence of fungi in arthropod bodies from samples of P. vulgares L. and V. unguiculata L., examined water activity from the samples and studied the effects of irradiation for arthropod deinfestation and fungal load reduction in P. vulgares L. and V. unguiculata L. grains. The samples were collected in different retailers within São Paulo city. One kilogram of 11 several varieties of beans were purchased. Sodium hypochlorite (0,5 %) were used for sample disinfection, washed in distilled water and distributed 10 beans per Petri dish in Potato Dextose Agar medium. Dishes were incubated at 25 ± 1°C for 5 days. The same procedure was adopted for the insects found in the samples. Samples were irradiated at 5.0 kGy and 10,0 kGy and the insects in dose range from 0 to 3,4 kGy, in the multipurpose gamma-irradiator 60Co IPEN/CNEN/SP. Several fungal genera were isolated independently of bean type. It was verified the presence of fungi related to insects in all samples. The recommended dose for immediate and simultaneous lethality was 3,0 kGy in C. maculatus, A. obtectus e Z. subfasciatus species. The 5,0 kGy and 10,0 kGy doses can reduce but cannot eliminate the fungal load at all. The values obtained in the water activity (Aw) analysis were below the ideal condition for fungal growth on grain.
12

Avaliação microbiológica, físico-química e sensorial de salada de repolho com cenoura minimamente processada após o tratamento por radiação gama destinado à pacientes imunocomprometidos ou com dietas especiais / Microbiological, physicochemical and sensory evaluation of cabbage and carrot minimally processed salad after radiation treatment intended to immunocompromised patients or with special diets

Thaise Cristine Fernandes Nunes 28 January 2015 (has links)
Durante e após o tratamento de câncer, de portadores de HIV ou transplantes, a alimentação pode oferecer um bem estar ao paciente, pois o ato de se alimentar corretamente auxilia as pessoas a se sentirem fortalecidas normalmente. Pessoas saudáveis possuem o seu sistema imunológico funcionando de maneira adequada, podendo combater pequenas quantidades de bactérias. Entretanto, pessoas imunocomprometidas podem não conseguir combater esta pequena quantidade de microrganismos e necessitam de uma dieta com baixa contagem microbiológica para evitar o contato com bactérias potencialmente danosas à saúde. Esta dieta é denominada dieta neutropênica. Esses pacientes são suscetíveis à contaminação alimentar, não sendo aconselhável a ingestão de produtos crus. A irradiação em vegetais, com baixas doses, tem a finalidade de reduzir a carga microbiana. Dessa forma a proposta deste trabalho foi obter dados de aspectos microbiológicos, sensoriais e físico-químicos em Mix Primavera minimamente processados submetidos a diferentes doses de radiação ionizante em dietas destinadas a pacientes imunocomprometidos ou imunossuprimidos. Foram utilizadas doses de 1,0kGy, 2,0kGy, 3,0kGy e 4,0kGy irradiadas no Irradiador Multipropósito 60Co localizado no Centro de Tecnologia das Radiações (CTR) IPEN-CNEN/SP. Foram realizadas análises microbiológicas (n=25), utilizando Petrifilm, análises sensoriais utilizando o teste sensorial de aceitação (n=30) e triangular (n=15) e análise de textura (n=90) no Laboratório de Microbiologia de Alimentos no Centro de Tecnologia das Radiações. As análises de textura foram realizadas com o auxílio de um texturômetro T.A.XT. Plus (Stable Micro System) equipado com a célula de carga de 50kg utilizando a sonda (probe) de corte triangular com lâmina Warner-Bratzler Knife com velocidade de descida de 2mm/s. Todos os resultados foram expressos em Newtons (N). Os resultados obtidos demostraram que para as análises microbiológicas os padrões foram seguidos de acordo com a RDC nº 12/01 ANVISA. A análise sensorial não apresentou diferença significativa entre as amostras, entretanto no teste triangular com as doses de 4,0kGy e controle houve diferença significativa entre as amostras, demonstrando que a amostra de 3,0kGy seria a mais indicada para o público específico deste trabalho. Pode-se concluir que para uma dieta neutropênica sugere-se uma dose de 2,0kGy. / During and after the treatment of cancer, people with HIV or transplants, the food intake can offer a well-being to the patient, because the action of eating right helps people to feel strong. Healthy people have their immune system working properly and can tolerate small amounts of bacteria. However, immunocompromised persons may not be able to and however immunocompromised people cannot fight this small amount of microorganisms and require a diet with very low microbiological count to avoid contact with potentially harmful bacteria. This is called neutropenic diet. These patients are susceptible to food contamination, so that its not advisable the ingestion of raw products. The vegetable irradiation with low doses has the purpose of reducing the microbial load. The aim of this study was to obtain data on microbiological, sensorial e physicochemical aspects in minimally processed Primavera salad irradiated with different doses of gamma radiation designed to immunocompromised patients. It were used doses of 1.0kGy, 2.0kGy, 3.0kGy and 4.0kGy irradiated in the Multipurpose Irradiator 60Co located in Radiation Technology Center. Microbiological analyzes were performed (n=25) using Petrifilm, sensory analysis using the sensory acceptance test (n=30) and triangular (n=15) and texture analysis (n=90) in the Food Microbiology Laboratory located at the Radiation Technology Center. The texture analysis was performed with the aid of a texturometer equipped with 5 kg load cell using a triangular cutting Warner-Bratzler Knife blade probe with the descent speed of 2mm/sec. All results were expressed in Newtons (N). The results showed that for microbiological analyzes the standards were followed according to the RDC 12/01 ANVISA. For the sensory test of acceptation no difference was found among the samples, however in the triangular test could be found slight differences between samples irradiated with 4.0kGy and control and there was significant difference among the sample, showing that the sample of 3.0kGy would be indicate for this specific public. It can be concluded that for a neutropenic diet the suggested dose is 2.0kGy.
13

Avaliação dos efeitos da radiação ionizante nos aspectos microbiológicos, físico-químicos e sensoriais de sorvetes / Evaluation of the ionizing radiation effects in microbiology, physical and chemical and sensory aspects of ice cream

Vladimir Dias Rogovschi 30 January 2015 (has links)
O sorvete é definido como gelado comestível obtido a partir da emulsão de gorduras e proteínas ou de uma mistura de água e açúcar, podendo ser adicionados outros ingredientes desde que não descaracterizem o produto. É considerado um alimento de alto valor nutricional, fornecendo lipídios, carboidratos, proteínas, cálcio, fósforo e outros minerais e vitaminas (A, B1, B2, B6, C, D, E e K), sendo um dos produtos mais importante e de maior interesse para as indústrias de derivados lácteos, devido à grande demanda pela população. As doenças relacionadas ao consumo de alimentos são consideradas um dos problemas mais relevantes. Diversos surtos alimentares relacionados a contaminação microbiológica de sorvetes foram relatados nas últimas décadas em países da Ásia, Europa e América. Acredita-se que o sorvete, por ser um alimento congelado, não apresenta riscos à saúde da população. Porém, ele é considerado um excelente meio para o crescimento de microrganismos, em função da sua composição, pH próximo a neutralidade e longo período de armazenamento. O objetivo deste trabalho foi avaliar os aspectos microbiológicos, sensoriais e físico-químicos de sorvetes de creme. As amostras de sorvete de creme foram irradiadas com raios gama (60Co), nas doses de 1,0kGy, 2,0kGy, 3,0kGy e 4,0kGy. As amostras destinadas à inoculação de Staphylococcus aureus (cepa ATCC 6538), Escherichia coli (cepa ATCC 11229) e Salmonella abaetetuba (cepa ATCC 35640) foram irradiadas com doses de 1,0, 2,0 e 3,0kGy. Conclui-se que as amostras irradiadas com 3,0kGy apresentaram uma redução em níveis não detectáveis para a maioria dos microrganismos estudados. O uso da radiação gama afetou a textura do sorvete, assim como os parâmetros de cor na análise colorimétrica. Os resultados da análise sensorial demonstram que a dose de melhor aceitação foi a de 3,0kGy. / The ice cream is defined as an emulsion of fats and proteins or a mixture of water and sugar, other ingredients may be added provided since they do not affect the product. It is considered a food of high nutritional value, providing lipids, carbohydrates, protein, calcium, phosphorus, and other minerals and vitamins (A, B1, B2, B6, C, D, E and K), and it is considered one of the most important products and higher interest to the dairy industry due to great demand by the consumers. The diseases related to food consumption are considered one of the most significant problems. Several outbreaks related to microbiological contamination of ice cream have been reported in recent decades in Asia, Europe and America. It is believed that the ice cream, as a frozen food, presents no risk to the population health. However, it is considered an excellent environment for the growth of microorganisms due to its composition, pH close to neutrality and long storage period. The aim of this study was to evaluate the microbiological, sensory and physicochemical aspects of ice cream. The ice cream samples were irradiated with gamma rays (60Co) with the doses of 1.0kGy, 2.0kGy, 3.0kGy and 4.0kGy. The samples intended for the inoculation of Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 11229) and Salmonella abaetetuba (ATCC 35640) have been irradiated with doses of 1.0, 2.0 and 3.0kGy. It can be concluded that the dose of 3.0kGy was adequate to reduce most of the studied microorganisms to undetected levels. The use of gamma radiation affected the texture and the parameters of the colorimetric analyses of the ice cream. The results of the sensorial analyses showed that the better accepted dose was 3.0kGy.
14

Disponibilidade de ferro em grãos de feijão comum (Phaseolus vulgaris L.) irradiados. / Availability of iron in grains commom beans (Phaseolus vulgaris l.) irradiated.

Brigide, Priscila 16 April 2002 (has links)
O feijão é a leguminosa mais consumida no Brasil, porém, o rendimento médio da lavoura no Brasil é baixo, devido, entre outros fatores, a infestação dos grãos. Para combater essas perdas, o processo de irradiação é uma alternativa saudável, quando comparada aos tratamentos químicos. Esta pesquisa teve por objetivo avaliar a disponibilidade de ferro em feijão comum irradiado (doses de 0, 2, 6 e 10 kGy) cru e submetido à cocção. Foi realizada a determinação da composição centesimal, dos antinutricionais (taninos e fitatos) e da diálise de ferro pelo método "in vitro". A cocção diminuiu todos os itens da composição centesimal, com exceção dos carboidratos disponíveis, obtendo os seguintes teores: proteína 27,4 e 23,9; lipídeos 1,2 e 1,1; fibras 23,7 e 18,6, carboidratos 43,3 e 52,5, respectivamente, para grãos crus e cozidos. Houve também diminuição na quantidade de taninos a qual se correlacionou inversamente com as doses aplicadas, com exceção da dose de 2 kGy, variando de 1,56 (10 kGy) a 2,49 (2 kGy) para grãos crus e traços (10 kGy) a 0,103 (2 kGy) para grãos cozidos. Os teores de fitatos variaram de 4,63 (2 kGy) a 8,28 (0 kGy) e 5,29 (6 kGy) a 9,55 (0 kGy), respectivamente, para grãos crus e cozidos. Em relação ao ferro dialisado, os teores variaram de 1,16 (0 kGy a 2,39 (6 kGy) e 5,33 (0 kGy) a 8,02 (6 kGy), respectivamente, para grãos crus e cozidos. A irradiação com dose de 6 kGy apresentou efeito positivo em relação à disponibilidade do fe rro em feijão tanto cru como cozido, sendo recomendada para a utilização. / Commom bean is the legume more consuming in Brazil, however, the average income of the farming in Brazil is low must the infestaction of the grains, to fight these losses the irradiation process is an alternative healthful if compared the chemical handlings. The objective of this research was evaluate the iron availability in irradiated raw and cooked beans (doses of 0, 2, 6 and 10 kGy). It was carried through the centesimal composition, antinutritional factors (tannins and phytate) and iron dialyses for the method "in vitro". Cooking diminished the mainly components of the composition with exception of available carbohydrates, the protein content of 27.4 and 23.9; fat 1.2 and 1.1; fibre 23.7 and 18.6, carbohydrates 43.3 and 52.5; respectively for raw grains and cooked. It also had reduction in the amount of tannin which if correlated reversely with the applied doses, with exception of the dose of 2 kGy, varying of 1.56 (10 kGy) to 2.49 (2 kGy) to the for raw grains and traces (10 kGy) to 0.103 (2 kGy ) for grains cooked. The phytate varied of 4.63 (2 kGy) to 8.28 (0 kGy) and 5.29 (6 kGy) to the 9.55 (0 kGy), respectively for raw grains and cooked. In relation to the dialysed iron, the content varied of 1.16 (0 kGy) to 2.39 (6 kGy) and 5.33 (0 kGy) to the 8.02 (6 kGy), respectively for raw grains and cooked The dose of 6 kGy showed positive effect availability such as raw as cooked grain, it being recommended for the utilization.
15

Determinação da dose de radiação ionizante para conservação de três cultivares híbridos de cebola (Allium cepa L.) / Ascertainment of ionizing radiation dose to the conservation of three hybrid onions cultivars (Allium cepa L.)

Souza, Mirela Andressa Maluf 05 November 2014 (has links)
A cebola é a terceira hortaliça mais produzida do mundo, sendo que o Brasil é o oitavo produtor mundial, participando com 2% dessa produção e 36% da produção sul-americana. O Brasil é um dos maiores consumidores de cebola do mundo, sendo a sua maior parte comercializada in natura. A cebola, como as demais hortaliças, é um produto altamente perecível, o que determina importantes perdas pós-colheitas se não forem observadas as devidas técnicas de produção. O objetivo do presente trabalho foi determinar a dose de radiação gama específica para os cultivares híbridos Aguarius, Goiana e Optima, baseada na conservação da cebola por um período de armazenamento, e determinar os efeitos da radiação gama sobre as características físico-químicas. Após a irradiação das cebolas com doses de 40, 60, 80 e 100 Gy, as cebolas foram mantidas a temperatura e umidade relativa do ar ambiente. As seguintes análises foram realizadas mensalmente: perda de massa fresca, por um período de 90 dias de armazenamento, brotamento externo e putrefação, coloração interna e teor de sólidos solúveis por um período de 150 dias e análises sensoriais (Aparência Geral Externa, Firmeza, Aparência Geral Interna, Odor e Brilho), por um período de 120 dias. Tendo em vista os resultados obtidos foi possível verificar que o processo de irradiação inibiu o brotamento e manteve as características sensoriais e físico-químicas, analisadas nesse trabalho, permitindo a conservação das cebolas por 120 dias, no mínimo. Dentre as doses de radiação analisadas e os cultivares, o tratamento de 60 Gy para a cultivar Aguarius se fez mais eficiente para a conservação das cebolas por um período de no mínimo 120 dias. Já para a Optima as doses de 40, 60, 80, 100 Gy se mostraram eficientes para a conservação da cebola por um período prolongado de armazenamento. E para a Goiana, na maior parte do tempo, praticamente não houve diferença na conservação das cebolas irradiadas ou não / Onion is the third most produced vegetable in the world. The Brazilian production is the eight largest one in the world ranking, accounting for 2% of the worldwide production and for 36% of the South American production. Brazilians are one of the largest consumers of onion, most of it traded in the fresh market. Onion, as other vegetables, is a high perishable product, and that can determinate significant post-harvest losses in case of appropriate production techniques were not observed. This study aimed to determinate the specific gamma radiation dose to the hybrid onion cultivars Aguarius, Goiana and Optima, based on the conservation of the onion for a long stocking period, and also to determinate the effects of the gamma radiation on the physical and chemical properties. After the irradiation of the onions with doses of 40, 60, 80 and 100 Gy, onions were conserved in relative temperature and humidity conditions. The following analyses were applied in a monthly basis: loss of fresh mass, for a stocking period of 90 days, external sprout and putrefaction, internal coloring and soluble solids level for a period of 150 days and sensorial analyses (external general appearance, sturdiness, internal general appearance, smell and brightness), for a period of 120 days. Based on the outcome, it was possible to note that the irradiation process has inhibited the sprout process and maintained the sensorial, physical and chemical properties that have been analyzed in this studied, allowing the onion conservation for 120 days, at least. Among the analyzed radiation doses and the onion cultivars, the treatment with 60 Gy to the Aguarius cultivar was the most efficient for the onion conservation for a period of 120 days at least. To Optima cultivar, the doses of 40, 60, 80, 100 Gy were the most efficient for the onion conservation for a long stocking period. And to Goiana cultivar, during the most part of the time, there were almost no difference in the conservation of onions irradiated or not
16

Development of a chemical dosimeter for electron beam food irradiation

Rivadeneira, Ramiro Geovanny 16 August 2006 (has links)
A chemical solution composed of paraffin wax, chloroform, and methyl yellow biological indicator was shaped into a solid 3-D apple phantom to determine absorbed dose from e-beams and X-rays. The purpose of this research was to determine the most uniform irradiation treatment on apple-phantoms (a complex shaped target) and GAFCHROMIC® HD-810 films using electron beams from (1) a 2 MeV Van de Graaff (VDG) accelerator, (2) a 10 MeV Linear Accelerator (LINAC), and (3) X-rays from a 5 MeV LINAC. Irradiation with the VDG accelerator confirmed that tilting the apple-phantom yaxis towards the e-beam source by 90 degrees, 45, and 22.5 degrees resulted in more uniform treatment in both the methyl yellow apple phantom and HD-810 film. The phantoms were over-exposed at the top and bottom regions when their y-axis was oriented exactly parallel to the e-beam at 22.5-degrees. The 45-degree orientation ensured uniformity throughout the whole apple surface without overexposing it at the top and bottom. In contrast, the 90-degree orientation resulted in the least effective treatment with the bottom and top region not receiving any radiation. A 10 MeV dual e-beam showed uniform penetration from top to bottom in the HD-810 film and apple phantoms. The HD-810 film responded linearly with doses up to 1.5 kGy while the methyl yellow response was non-linear up to 0.5 kGy maximum. The X-ray irradiation completely penetrated the apple phantoms from top to bottom showing excellent lateral uniformity at different penetration depths.
17

Determinação da dose de radiação ionizante para conservação de três cultivares híbridos de cebola (Allium cepa L.) / Ascertainment of ionizing radiation dose to the conservation of three hybrid onions cultivars (Allium cepa L.)

Mirela Andressa Maluf Souza 05 November 2014 (has links)
A cebola é a terceira hortaliça mais produzida do mundo, sendo que o Brasil é o oitavo produtor mundial, participando com 2% dessa produção e 36% da produção sul-americana. O Brasil é um dos maiores consumidores de cebola do mundo, sendo a sua maior parte comercializada in natura. A cebola, como as demais hortaliças, é um produto altamente perecível, o que determina importantes perdas pós-colheitas se não forem observadas as devidas técnicas de produção. O objetivo do presente trabalho foi determinar a dose de radiação gama específica para os cultivares híbridos Aguarius, Goiana e Optima, baseada na conservação da cebola por um período de armazenamento, e determinar os efeitos da radiação gama sobre as características físico-químicas. Após a irradiação das cebolas com doses de 40, 60, 80 e 100 Gy, as cebolas foram mantidas a temperatura e umidade relativa do ar ambiente. As seguintes análises foram realizadas mensalmente: perda de massa fresca, por um período de 90 dias de armazenamento, brotamento externo e putrefação, coloração interna e teor de sólidos solúveis por um período de 150 dias e análises sensoriais (Aparência Geral Externa, Firmeza, Aparência Geral Interna, Odor e Brilho), por um período de 120 dias. Tendo em vista os resultados obtidos foi possível verificar que o processo de irradiação inibiu o brotamento e manteve as características sensoriais e físico-químicas, analisadas nesse trabalho, permitindo a conservação das cebolas por 120 dias, no mínimo. Dentre as doses de radiação analisadas e os cultivares, o tratamento de 60 Gy para a cultivar Aguarius se fez mais eficiente para a conservação das cebolas por um período de no mínimo 120 dias. Já para a Optima as doses de 40, 60, 80, 100 Gy se mostraram eficientes para a conservação da cebola por um período prolongado de armazenamento. E para a Goiana, na maior parte do tempo, praticamente não houve diferença na conservação das cebolas irradiadas ou não / Onion is the third most produced vegetable in the world. The Brazilian production is the eight largest one in the world ranking, accounting for 2% of the worldwide production and for 36% of the South American production. Brazilians are one of the largest consumers of onion, most of it traded in the fresh market. Onion, as other vegetables, is a high perishable product, and that can determinate significant post-harvest losses in case of appropriate production techniques were not observed. This study aimed to determinate the specific gamma radiation dose to the hybrid onion cultivars Aguarius, Goiana and Optima, based on the conservation of the onion for a long stocking period, and also to determinate the effects of the gamma radiation on the physical and chemical properties. After the irradiation of the onions with doses of 40, 60, 80 and 100 Gy, onions were conserved in relative temperature and humidity conditions. The following analyses were applied in a monthly basis: loss of fresh mass, for a stocking period of 90 days, external sprout and putrefaction, internal coloring and soluble solids level for a period of 150 days and sensorial analyses (external general appearance, sturdiness, internal general appearance, smell and brightness), for a period of 120 days. Based on the outcome, it was possible to note that the irradiation process has inhibited the sprout process and maintained the sensorial, physical and chemical properties that have been analyzed in this studied, allowing the onion conservation for 120 days, at least. Among the analyzed radiation doses and the onion cultivars, the treatment with 60 Gy to the Aguarius cultivar was the most efficient for the onion conservation for a period of 120 days at least. To Optima cultivar, the doses of 40, 60, 80, 100 Gy were the most efficient for the onion conservation for a long stocking period. And to Goiana cultivar, during the most part of the time, there were almost no difference in the conservation of onions irradiated or not
18

Post mortem physicochemical properties of radurized chicken muscle

Matin, Muhammed Abdul January 1973 (has links)
Chicken breast muscles (Pectoralis major and Pectoralis minor) were subjected to low doses of gamma radiation (≤ 0.50 Mrad) within 20-30 min. post-slaughter. pH decline extractability of different muscle protein fractions, shear force, isometric tension pattern and sarcomere length were evaluated at definite intervals of post mortem storage period. pH measurements from 1/2 hour to 72 hours post mortem revealed a stimulation of pH decline immediately after irradiation in 0.25 and 0.50 Mrad treated muscle samples but this effect was subsequently found to be nullified and an ultimate pH of about 5.55 was reached between 6-12 hours in all the samples. Extractability of total soluble and total myofibrillar proteins of muscle increased with post mortem time. A clear effect of irradiation treatments of increased extractability of actomyosin especially in the post rigor period was observed and this effect was more noticeable in 0.50 Mrad than in 0.25 Mrad samples. Comparatively less extractable actomyosin was found during the post rigor period of storage particularly in control samples. There was no significant effect of radiation doses, time of storage or their interactions on the solubility of sarcoplasmic proteins or of four minor fractions of protein and non-protein substances. The level of extractable actomyosin was found to be significantly related (r² = 0.12; df=46) with the corresponding shear press measurements. Irradiated samples had significantly higher mean shear values and more extractable actomyosin than the control samples especially during the post rigor period. Irradiation (0.125 and 0. 250 Mrad) was found to stimulate post mortem development of isometric tension in muscle strips. In irradiated samples maximum tension was developed about 2 hours ahead of the corresponding controls. A 50% decline of isometric tension was achieved in 6-8 hours post mortem, while a 50% decline of tension in control samples required more than 12 hours. The general relationship of isometric tension pattern and extractability of actomyosin was found to be low. Sarcomere length was related (r² = .38; df = 6) with shear values such that a small change in sarcomere length was found to result in a relatively large change in shear press values. Irradiated samples with relatively shorter sarcomeres in the post rigor period were found to have significantly lower mean shear values when compared with their respective control samples. / Land and Food Systems, Faculty of / Graduate
19

Studies on the rehydration of irradiated freeze-dried beef

Ni, Yeng-Wei January 1969 (has links)
The total water uptake, rate of water uptake, extract release volume and maximum shear force were measured on a series of samples of irradiated freeze-dried beef. Forty seven pieces of round steak (2.5 cm x 2.5 cm x 10.4 cm or 1" x 1" x 4") were irradiated at one, three and five megarad. The control samples were not irradiated. Half of the samples were irradiated when fresh, and the other half were irradiated after freeze drying. This procedure has been defined as the "fresh-dry" irradiation sequence throughout the report. The samples were frozen in an air blast at two temperatures (-22.2°C and -56.1°C). Freeze-drying was carried out below 300 microns of Hg and a maximum shelf temperature of 15.6°C (60°F). There appears to be three phases of water uptake: 1) A very rapid, almost instantaneous, absorption. 2) A more gradual uptake (called Part.1 in the report). 3) A relatively slow asymptotic approach to an equilibrium condition (Part 2). These two last phases are shown to be straight lines when the logarithm of the water uptake is plotted against the logarithm of the immersion time. Irradiation level has no significant effect on the final water content or on the slow asymptotic absorption (Part 2) or the extract release volume, but has a significant effect on the gradual water uptake (Part 1) and on the shear press force. Fresh-dry irradiation sequence (and freezing rate) have a significant effect on the total water uptake and on the slow asymptotic water (Part 2) uptake, but not on the gradual water uptake (Part 1), or on the extract release volume or on the shear press forces. Freezing rates have a significant effect on the total water uptake, but not on the slow asymptotic water uptake (Part 2), on the gradual water uptake (Part 1), on the extract release volume or on the shear press forces. The highest total water uptake was found for the meat irradiated when fresh, and slow frozen at -2 2.2°C. The mechanism of the gradual absorption appears to follow a phenomena of water flow, as evidenced by the straight line relationship found in the plots of logarithm water uptake versus logarithm immersion time. / Land and Food Systems, Faculty of / Graduate
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Disponibilidade de ferro em grãos de feijão comum (Phaseolus vulgaris L.) irradiados. / Availability of iron in grains commom beans (Phaseolus vulgaris l.) irradiated.

Priscila Brigide 16 April 2002 (has links)
O feijão é a leguminosa mais consumida no Brasil, porém, o rendimento médio da lavoura no Brasil é baixo, devido, entre outros fatores, a infestação dos grãos. Para combater essas perdas, o processo de irradiação é uma alternativa saudável, quando comparada aos tratamentos químicos. Esta pesquisa teve por objetivo avaliar a disponibilidade de ferro em feijão comum irradiado (doses de 0, 2, 6 e 10 kGy) cru e submetido à cocção. Foi realizada a determinação da composição centesimal, dos antinutricionais (taninos e fitatos) e da diálise de ferro pelo método “in vitro”. A cocção diminuiu todos os itens da composição centesimal, com exceção dos carboidratos disponíveis, obtendo os seguintes teores: proteína 27,4 e 23,9; lipídeos 1,2 e 1,1; fibras 23,7 e 18,6, carboidratos 43,3 e 52,5, respectivamente, para grãos crus e cozidos. Houve também diminuição na quantidade de taninos a qual se correlacionou inversamente com as doses aplicadas, com exceção da dose de 2 kGy, variando de 1,56 (10 kGy) a 2,49 (2 kGy) para grãos crus e traços (10 kGy) a 0,103 (2 kGy) para grãos cozidos. Os teores de fitatos variaram de 4,63 (2 kGy) a 8,28 (0 kGy) e 5,29 (6 kGy) a 9,55 (0 kGy), respectivamente, para grãos crus e cozidos. Em relação ao ferro dialisado, os teores variaram de 1,16 (0 kGy a 2,39 (6 kGy) e 5,33 (0 kGy) a 8,02 (6 kGy), respectivamente, para grãos crus e cozidos. A irradiação com dose de 6 kGy apresentou efeito positivo em relação à disponibilidade do fe rro em feijão tanto cru como cozido, sendo recomendada para a utilização. / Commom bean is the legume more consuming in Brazil, however, the average income of the farming in Brazil is low must the infestaction of the grains, to fight these losses the irradiation process is an alternative healthful if compared the chemical handlings. The objective of this research was evaluate the iron availability in irradiated raw and cooked beans (doses of 0, 2, 6 and 10 kGy). It was carried through the centesimal composition, antinutritional factors (tannins and phytate) and iron dialyses for the method “in vitro”. Cooking diminished the mainly components of the composition with exception of available carbohydrates, the protein content of 27.4 and 23.9; fat 1.2 and 1.1; fibre 23.7 and 18.6, carbohydrates 43.3 and 52.5; respectively for raw grains and cooked. It also had reduction in the amount of tannin which if correlated reversely with the applied doses, with exception of the dose of 2 kGy, varying of 1.56 (10 kGy) to 2.49 (2 kGy) to the for raw grains and traces (10 kGy) to 0.103 (2 kGy ) for grains cooked. The phytate varied of 4.63 (2 kGy) to 8.28 (0 kGy) and 5.29 (6 kGy) to the 9.55 (0 kGy), respectively for raw grains and cooked. In relation to the dialysed iron, the content varied of 1.16 (0 kGy) to 2.39 (6 kGy) and 5.33 (0 kGy) to the 8.02 (6 kGy), respectively for raw grains and cooked The dose of 6 kGy showed positive effect availability such as raw as cooked grain, it being recommended for the utilization.

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