• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 198
  • 148
  • 64
  • 22
  • 22
  • 22
  • 22
  • 22
  • 22
  • 7
  • 5
  • 5
  • 5
  • 2
  • 1
  • Tagged with
  • 520
  • 163
  • 46
  • 45
  • 44
  • 39
  • 38
  • 37
  • 36
  • 36
  • 33
  • 31
  • 29
  • 26
  • 24
  • 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.
411

Down-regulation of defense gene transcripts of Rhizoctonia solani-infected bean seedlings in response to inoculation with non-pathogenic fungi

Wen, Kui January 2004 (has links)
No description available.
412

Effects of density and host plant type on fecundity and survival of Delia radicum (Bouché), D. Antiqua (Meigen) and D. Platura (Meigen) (Diptera: Anthomyiidae)

Noronha, Christine M. (Christine Mary) January 1992 (has links)
No description available.
413

Influence of primary hypogenous seeds of phaseolus coccineus in cucurbitacin-containing phytonematicides on plant growth and namatode suppression

Ramoetlo, Motsatsi Priscilla January 2022 (has links)
Thesis (M.Sc.(Plant Protection)) -- University of Limpopo, 2022 / Runner beans are extremely sensitive to root-knot (Meloidogyne species) nematodes. Phytonematicides had been consistently used in managing population densities of Meloidogyne species in various crops, with the application technologies being restricted to the ground leaching technology (GLT) and botinemagation technology, each with its own advantages and disadvantages. The use of seeds as carriers of active ingredients of phytonematicides and then drying prior to sowing, is being considered as another potential application strategy in seeds with hypogeal germination. In such seeds, during seedling emergence the seed cover and the endosperm remain below the soil surface, just above the developing root system. As a result, in phytonematicide-primed seeds, the seed structures could serve as carriers for the active ingredients of phytonematicides. In cucurbitacin phytonematicides, Nemarioc-AL and Nemafric-BL phytonematicides contain cucurbitacin A and B, respectively as active ingredients. The objectives of the study were two-fold, namely, to determine whether runner bean (Phaseolus coccineus L.) seeds would (1) serve as carriers of active ingredients of cucurbitacin-containing phytonematicides without affecting seed germination under in vitro conditions, (2) serve as carriers of cucurbitacins intended for suppression of M. incognita population densities under greenhouse and microplot conditions. Two separate studies were conducted under laboratory conditions, with seven treatment solutions at 0, 2, 4, 8, 16, 32 and 64% Nemafric-BL or Nemarioc-AL phytonematicide. After exposure to separate solutions for 2 h, runner bean seeds were dried on laboratory benches for 72 h. Treatments were arranged in a completely randomised design (CRD), with 8 replications. Two layers of filter papers were placed inside each Petri dish seeded with 10 primed and dried seeds. Petri dishes were incubated inside LABCON growth chamber at 25ºC and 75% relative humidity. Successful seed germination, viewed as emergence of radicle from the testa, was recorded daily for a period of 10 days, with each count being removed from Petri dish to avoid re-counting. Under greenhouse and microplot conditions, primed-and dried seeds were sown in plastic pots containing 2 700 ml steam-pasteurised sandy loam soil, arranged in a randomised complete block design, replicated six times and eight times, respectively. Each seedling was inoculated by distributing 5 000 eggs and second-stage juveniles (J2) of M. incognita race 4 using a 50 ml plastic syringe. Originally, pots were irrigated using 500 ml chlorine-free tapwater, which was reduced to half after seedling emergence at every other day. Plant variables were collected at 56 days after inoculation and data were subjected to the Curve-fitting Allelochemical Response Dose algorithm model. In vitro, germination percentage (R 2 = 0.96), radicle length (R 2 = 0.89) and plumule diameter (R 2 = 0.96) versus Nemarioc-AL phytonematicide exhibited positive quadratic relations. Similarly, the variables versus Nemafric-BL phytonematicide, exhibited positive quadratic relations. In vitro, Mean Concentration Stimulation Point (MCSP) value of Nemarioc-AL phytonematicide on runner bean seeds was 1.05%, whereas for Nemafric-BL phytonematicide MCSP value was 0.58%. Under greenhouse conditions, plant height (R 2 = 0.97), chlorophyll content (R 2 = 0.92), dry shoot mass (R 2 = 0.98), dead nodule number (R 2 = 0.90), total pod number (R 2 = 0.97) and active nodule number (R 2 = 0.93) versus Nemarioc-AL phytonematicide exhibited positive quadratic relations., Similarly, chlorophyll content (R 2 = 0.95), gall rating (R 2 = 0.82), dry shoot weight (R 2 = 0.69), stem diameter (R 2 = 0.85) and total nodule number (R 2 = 0.86) versus Nemafric-BL phytonematicide exhibited positive quadratic relations. Under greenhouse conditions, MCSP values for Nemarioc-AL and Nemafric-BL phytonematicides were 4.18 and 3.69%, respectively. Under microplot conditions, total number of nodules (R 2 = 0.88), number of nodules dead (R 2 = 0.99), number of nodules active (R 2 = 0.95), fresh root mass (R 2 = 0.99), and fresh pod mass (R 2 = 0.99) versus Nemarioc-AL phytonematicide, exhibited positive quadratic relations, whereas plant height (R 2 = 0.85), number of nodules dead (R 2 = 0.87), dry shoot mass (R 2 = 0.97), fresh root mass (R 2 = 0.97) and total number of nodules (R 2 = 0.63) versus Nemafric-BL phytonematicide exhibited positive quadratic relations. Under microplot conditions, MCSP values for Nemarioc-AL and Nemafric-BL phytonematicides were 3.76 and 3.93%, respectively, each with ∑k = 0. All degrees of Nemarioc-AL and Nemafric-BL phytonematicides profoundly reduced nematode numbers under greenhouse and microplot trials. Based on the information obtained from this study, it was confirmed that runner bean (P. coccineus) is sensitive to Nemafric-BL and Nemarioc-AL phytonematicides supported by the Curve-fitting Allelochemical Response Dose (CARD) model results due to most plant variables that had sensitivity values of zero. In conclusion, the priming technology should be developed further since it has the potential of being successful in nematode management in seeds with hypogeal germination / National Research Foundation (NRF) and Potatoes South Africa
414

UTILIZATION OF NUTRIENTS IN ANIMAL AND PLANT ALTERNATIVE FEED INGREDIENTS FOR BROILER CHICKENS AND PIGS

Abidemi Adekoya (17015808) 13 October 2023 (has links)
<p dir="ltr">The objective of this thesis was to evaluate the nutrient digestibility in alternative animal and plant sources of feed ingredients for chickens and pigs. Therefore, 5 studies were carried out to determine the nutrient utilization in poultry meal (<b>PM</b>), faba beans (<b>FB</b>), and 3 cultivars field peas (<b>FP</b>).</p><p dir="ltr">In the first study, 2 experiments investigated the energy and phosphorus utilization of PM for broiler chickens. Poultry meal was used to substitute corn and soybean meal in the reference diet at 0, 80, or 160 g/kg in Experiment 1. Whereas PM was included in the diet at 0, 50, or 100 g/kg in Experiment 2. A total of 192 birds were allotted to 3 experimental diets in both experiments. The estimated ileal digestible energy (<b>IDE</b>), metabolizable energy (<b>ME</b>), and nitrogen-corrected metabolizable energy (<b>MEn</b>) for PM were 4,002, 3,756, and 3,430 kcal/kg DM, respectively. In Experiment 2, the true ileal digestibility (<b>TID</b>) and true total tract utilization (<b>TTTU</b>) of P in PM were 77.5 and 79.0%, respectively.</p><p dir="ltr">The second study consisted of 3 experiments. In the first experiment, 240 birds were assigned to 5 diets to determine the energy values of FB and DS admiral FP (<b>FPD</b>). In Experiment 1, the test ingredients were incorporated into a corn-soybean meal-based diet at 0, 150 or 300 g/kg. The IDE, ME, and MEn for FB were 2,541, 2,628, and 2,394 kcal/kg, respectively. The respective values for FPD were 2,254, 2,540, and 2,331 kcal/kg DM. In each of Experiments 2 and 3, 162 birds were assigned to 3 diets. Faba beans was included at 21, 42, or 63% and FPD at 16, 32, or 48% in Experiments 2 and 3, respectively. The TID and TTTU of P in FB were 66.5 and 66.7%, respectively. The corresponding values for FPD were 73.4 and 73.8%.</p><p dir="ltr">The third study consisted of 3 experiments. In Experiment 1, the energy values for Hampton FP (<b>FPH</b>) and 4010 FP (<b>FP4</b>) fed to broiler chickens were estimated. Two hundred and forty birds were assigned to 5 diets. The test ingredients were included at 0, 150 or 300 g/kg into a corn-soybean meal-based reference diet. With regression analysis, the determined IDE, ME, and MEn were 3,274, 3,033, and 2,850 kcal/kg DM in FPH, respectively, in FP4 the energy values were 3,019, 3,155, and 2,991 kcal/kg DM, respectively. The P utilization in FPH and FP4 were determined in Experiments 2 and 3, respectively. The corresponding TID and TTTU of P in FPH were 74.6% and 68.3%, and 74.3 and 61.7% in FP4.</p><p dir="ltr">Two experiments were conducted in the fourth study to estimate the digestible energy (<b>DE</b>) and ME in FB and FP fed to pigs. Twenty-four barrows were assigned to 3 dietary treatments in each of the experiments. Faba beans or FPD in Experiment 1 and FPH or FP4 in Experiment 2 were included in the diet at 0 or 300 g/kg. The determined DE and ME values for FB using the total collection method were 3,772 and 3,606 kcal/kg DM and in FPD were 3,683 and 3,589 kcal/kg DM, respectively. In Exp. 2, the respective DE and ME for FPH were 4,164 and 4,014 kcal/kg DM and for FP4 were 3,574 and 3,467 kcal/kg DM.</p><p dir="ltr">In the last study, standardized ileal digestibility (<b>SID</b>) of amino acids (<b>AA</b>) in faba beans and three cultivars of FP between broiler chickens and pigs were compared. The test ingredients were the only source of protein providing 160 g/kg crude protein and a nitrogen-free diet was prepared to estimate the basal endogenous losses of AA. The same set of five diets was used across both species. The SID of Lys in FB, FPD, and FPH exceeded 90% but in FP4 it was 85.1% for broiler chickens. Whereas for pigs the SID of Lys in FB, FPD, and FPH exceeded 80% but for FP4 it was 89.8%. The SID of Met in the test ingredients ranged from 72.1 to 89.8% and 68.1 to 81.8% for broiler chickens and pigs, respectively. In general, the SID of AA in the test ingredients were greater compared with chickens. The energy, P, and AA digestibility of the test ingredients determined in the five studies could be used in diet formulation for chickens and pigs.</p>
415

Analytical Methods for Toxic Metals and Proteins and Synthesis of Perovskites

Smith, Debbie A. 16 November 2010 (has links)
No description available.
416

The Effects of Pressure-Assisted Thermal Processing on the Quality Attributes of Black Beans (<i>Phaseolus vulgaris L.</i>)

Somerville, Jeremy Alan January 2009 (has links)
No description available.
417

Caracterização de cultivares de feijão para pré- de grãos desidratados de cozimento rápido e processamento industrial / Characterization of bean cultivars for preprocessing of dehydrated quick-cooking grains and industrial canning

Schoeninger, Vanderleia 26 October 2015 (has links)
Made available in DSpace on 2017-07-10T19:24:03Z (GMT). No. of bitstreams: 1 Tese revisada_ (Vanderleia) 29 10 2015.pdf: 2119451 bytes, checksum: 2a331a8e454522cd4dc600544af51cd4 (MD5) Previous issue date: 2015-10-26 / Currently an alternative that meets the demands of the modern consumer is the industrial processing. Due to the necessity of scientific materials about beans industrial processing in the national literature, then the objective in the first stage of this work (Paper 1) was prepare a review about this topic. Were presented some concepts and details of the industrial processing, unit operations and quality parameters evaluated in canned beans. In sequence (Paper 2) were presented the results of the study that evaluated the adaptability of eight bean cultivars for industrial processing. Cultivars evaluated were by commercial Carioca class: BRS Perola, BRS Estilo, BRS Ametista e BRS Notável and also the Black class: IPR Uirapuru, BRS Campeiro, BRS Esteio and BRS Esplendor. First the physical parameters of the grains were evaluated: water content, measurement of the size, roundness, weight of 100 seeds, density, bulk density, apparent moisture ratio and color components. Then the beans were processed at an industry of canning, using cans with a capacity of 420 g, in which the samples were put without the use of soaking. For sauce was used water at a temperature of 75°C and the cooking process and sterilization was performed in a rotary retort. The quality parameters were evaluated in canned beans: total, net and drained weight, headspace, damage index, color, soluble solids and total solids in the sauce, texture, acidity and pH. Data were submitted to multivariate analysis: Principal Components and Hierarchical Clustering. As a result it was found that the Carioca class BRS Estilo differs from others due to low drained weight that contributed to the increase of total solids in the broth, with low hardness values, not adapting to the type of process used in this experiment. In Black class were observed similar quality characteristics between cultivars BRS Esplendor and IPR Uirapuru, and between BRS Campeiro and BRS Esteio, especially this last one by having smaller index of damaged grains after processing. Lastly, in the last work (Paper 3) was presented information about a different option of product by beans, the quick cooking dehydrated, pointing details of the processing and the performance of Brazilian bean varieties, as well as the technological quality of the final product. In the processing of quick-cooking dried beans was used a Central Composite Design (CCD) with two factors. The first factor was cultivar, evaluating BRS Pérola, BRS Madrepérola, BRS Estilo and IAPAR 81. The second factor was concentration of NaHCO3 used in soaking operation followed by drying of the beans. Were evaluated the parameters: cooking time, damage index and color difference in the processed product. It was found that the effects on these quality parameters are dependent upon the cultivar factor, because BRS Estilo and BRS Madrepérola stood out due to reduced cooking time and color difference when compared to BRS Pérola and IAPAR 81. For BRS Estilo cultivar the increased of NaHCO3 concentration in the soaking reduced significantly the cooking time, with lower rates of damage when compared to BRS Madrepérola. Finally, the information in this work intends to contribute with future research on this topic and therefore increase the bean consumption, whether in the form of an innovative product like the quick cooking dehydrated or as canned beans. / Atualmente uma alternativa alimentar que atende às demandas do consumidor moderno é o processamento industrial do feijão. Devido à necessidade de materiais científicos sobre processamento industrial do feijão na literatura nacional, objetivou-se na primeira etapa deste trabalho (Artigo 1) elaborar uma revisão de literatura sobre o tema. São apresentados alguns conceitos e detalhes do processamento industrial, das operações unitárias e dos parâmetros de qualidade avaliados no feijão enlatado. Na sequência (Artigo 2), apresentam-se os resultados do trabalho que avaliou a adaptabilidade de oito cultivares de feijão ao processamento industrial. Foram avaliados cultivares da classe comercial Carioca: BRS Pérola, BRS Estilo, BRS Ametista e BRS Notável; da classe Preto: IPR Uirapuru, BRS Campeiro, BRS Esteio e BRS Esplendor. Primeiramente, foram verificados os parâmetros físicos nos grãos: teor de água, aferição das dimensões, esfericidade, massa de 100 grãos, densidade, massa específica aparente, coeficiente de hidratação e componentes de cor. Em seguida, os grãos foram processados em uma indústria do setor, utilizando-se embalagens metálicas com capacidade de 420 g, nas quais as amostras foram acondicionadas sem o emprego de hidratação prévia. Como calda, utilizou-se água na temperatura de 75 °C e o processo de cozimento e esterilização foi realizado em autoclave rotativa. No feijão enlatado, avaliaram-se os parâmetros de qualidade: peso bruto, líquido e drenado, altura de headspace, índice de danos, cor, sólidos solúveis e sólidos totais no caldo, textura, acidez e pH. Os dados foram submetidos à análise multivariada: componentes principais e de agrupamento. Como resultado, verificou-se que, na classe Carioca, o cultivar BRS Estilo diferencia-se dos demais, devido ao baixo peso drenado que contribuiu para o aumento de sólidos totais no caldo, com baixos valores de dureza, não se adaptando ao tipo de processo utilizado neste experimento. Na classe Preto, observaram-se características de qualidade semelhantes entre BRS Esplendor e IPR Uirapuru, e entre BRS Esteio e BRS Campeiro, destacando-se esta última por apresentar menores índices de grãos danificados após o processamento. Por fim, no último trabalho (Artigo 3), apresentam-se informações sobre uma opção diferenciada de produto derivado do feijão, o desidratado de cozimento rápido, apontando-se detalhes sobre o processamento e a performance de diferentes cultivares brasileiros, assim como a qualidade tecnológica. No processamento do feijão desidratado de cozimento rápido foi empregado um delineamento composto central (DCC) com dois fatores. O primeiro fator foi cultivar, avaliando-se BRS Pérola, BRS Madrepérola, BRS Estilo e IAPAR 81; o segundo fator foi a concentração de NaHCO3 (bicarbonato de sódio) empregado na hidratação, seguida da secagem dos grãos. Foram avaliados os parâmetros tempo de cozimento, índice de dano e diferença de cor no produto processado. Verificou-se que os efeitos nos parâmetros de qualidade são dependentes do fator cultivar, visto que BRS Estilo e BRS Madrepérola destacaram-se devido ao menor tempo de cozimento e diferença de cor, quando comparados ao BRS Pérola e IAPAR 81. Para BRS Estilo, o aumento na concentração de NaHCO3 reduz significativamente o tempo de cozimento, com menor índice de dano quando comparado ao cultivar BRS Madrepérola. Por fim, com as informações presentes neste trabalho pretende-se contribuir com pesquisas futuras sobre o tema e dessa forma incrementar o consumo do feijão, seja na forma de um produto inovador como o desidratado de cozimento rápido ou na forma de enlatado.
418

Caracterização de cultivares de feijão para pré- de grãos desidratados de cozimento rápido e processamento industrial / Characterization of bean cultivars for preprocessing of dehydrated quick-cooking grains and industrial canning

Schoeninger, Vanderleia 26 October 2015 (has links)
Made available in DSpace on 2017-05-12T14:47:17Z (GMT). No. of bitstreams: 1 Tese revisada_ (Vanderleia) 29 10 2015.pdf: 2119451 bytes, checksum: 2a331a8e454522cd4dc600544af51cd4 (MD5) Previous issue date: 2015-10-26 / Currently an alternative that meets the demands of the modern consumer is the industrial processing. Due to the necessity of scientific materials about beans industrial processing in the national literature, then the objective in the first stage of this work (Paper 1) was prepare a review about this topic. Were presented some concepts and details of the industrial processing, unit operations and quality parameters evaluated in canned beans. In sequence (Paper 2) were presented the results of the study that evaluated the adaptability of eight bean cultivars for industrial processing. Cultivars evaluated were by commercial Carioca class: BRS Perola, BRS Estilo, BRS Ametista e BRS Notável and also the Black class: IPR Uirapuru, BRS Campeiro, BRS Esteio and BRS Esplendor. First the physical parameters of the grains were evaluated: water content, measurement of the size, roundness, weight of 100 seeds, density, bulk density, apparent moisture ratio and color components. Then the beans were processed at an industry of canning, using cans with a capacity of 420 g, in which the samples were put without the use of soaking. For sauce was used water at a temperature of 75°C and the cooking process and sterilization was performed in a rotary retort. The quality parameters were evaluated in canned beans: total, net and drained weight, headspace, damage index, color, soluble solids and total solids in the sauce, texture, acidity and pH. Data were submitted to multivariate analysis: Principal Components and Hierarchical Clustering. As a result it was found that the Carioca class BRS Estilo differs from others due to low drained weight that contributed to the increase of total solids in the broth, with low hardness values, not adapting to the type of process used in this experiment. In Black class were observed similar quality characteristics between cultivars BRS Esplendor and IPR Uirapuru, and between BRS Campeiro and BRS Esteio, especially this last one by having smaller index of damaged grains after processing. Lastly, in the last work (Paper 3) was presented information about a different option of product by beans, the quick cooking dehydrated, pointing details of the processing and the performance of Brazilian bean varieties, as well as the technological quality of the final product. In the processing of quick-cooking dried beans was used a Central Composite Design (CCD) with two factors. The first factor was cultivar, evaluating BRS Pérola, BRS Madrepérola, BRS Estilo and IAPAR 81. The second factor was concentration of NaHCO3 used in soaking operation followed by drying of the beans. Were evaluated the parameters: cooking time, damage index and color difference in the processed product. It was found that the effects on these quality parameters are dependent upon the cultivar factor, because BRS Estilo and BRS Madrepérola stood out due to reduced cooking time and color difference when compared to BRS Pérola and IAPAR 81. For BRS Estilo cultivar the increased of NaHCO3 concentration in the soaking reduced significantly the cooking time, with lower rates of damage when compared to BRS Madrepérola. Finally, the information in this work intends to contribute with future research on this topic and therefore increase the bean consumption, whether in the form of an innovative product like the quick cooking dehydrated or as canned beans. / Atualmente uma alternativa alimentar que atende às demandas do consumidor moderno é o processamento industrial do feijão. Devido à necessidade de materiais científicos sobre processamento industrial do feijão na literatura nacional, objetivou-se na primeira etapa deste trabalho (Artigo 1) elaborar uma revisão de literatura sobre o tema. São apresentados alguns conceitos e detalhes do processamento industrial, das operações unitárias e dos parâmetros de qualidade avaliados no feijão enlatado. Na sequência (Artigo 2), apresentam-se os resultados do trabalho que avaliou a adaptabilidade de oito cultivares de feijão ao processamento industrial. Foram avaliados cultivares da classe comercial Carioca: BRS Pérola, BRS Estilo, BRS Ametista e BRS Notável; da classe Preto: IPR Uirapuru, BRS Campeiro, BRS Esteio e BRS Esplendor. Primeiramente, foram verificados os parâmetros físicos nos grãos: teor de água, aferição das dimensões, esfericidade, massa de 100 grãos, densidade, massa específica aparente, coeficiente de hidratação e componentes de cor. Em seguida, os grãos foram processados em uma indústria do setor, utilizando-se embalagens metálicas com capacidade de 420 g, nas quais as amostras foram acondicionadas sem o emprego de hidratação prévia. Como calda, utilizou-se água na temperatura de 75 °C e o processo de cozimento e esterilização foi realizado em autoclave rotativa. No feijão enlatado, avaliaram-se os parâmetros de qualidade: peso bruto, líquido e drenado, altura de headspace, índice de danos, cor, sólidos solúveis e sólidos totais no caldo, textura, acidez e pH. Os dados foram submetidos à análise multivariada: componentes principais e de agrupamento. Como resultado, verificou-se que, na classe Carioca, o cultivar BRS Estilo diferencia-se dos demais, devido ao baixo peso drenado que contribuiu para o aumento de sólidos totais no caldo, com baixos valores de dureza, não se adaptando ao tipo de processo utilizado neste experimento. Na classe Preto, observaram-se características de qualidade semelhantes entre BRS Esplendor e IPR Uirapuru, e entre BRS Esteio e BRS Campeiro, destacando-se esta última por apresentar menores índices de grãos danificados após o processamento. Por fim, no último trabalho (Artigo 3), apresentam-se informações sobre uma opção diferenciada de produto derivado do feijão, o desidratado de cozimento rápido, apontando-se detalhes sobre o processamento e a performance de diferentes cultivares brasileiros, assim como a qualidade tecnológica. No processamento do feijão desidratado de cozimento rápido foi empregado um delineamento composto central (DCC) com dois fatores. O primeiro fator foi cultivar, avaliando-se BRS Pérola, BRS Madrepérola, BRS Estilo e IAPAR 81; o segundo fator foi a concentração de NaHCO3 (bicarbonato de sódio) empregado na hidratação, seguida da secagem dos grãos. Foram avaliados os parâmetros tempo de cozimento, índice de dano e diferença de cor no produto processado. Verificou-se que os efeitos nos parâmetros de qualidade são dependentes do fator cultivar, visto que BRS Estilo e BRS Madrepérola destacaram-se devido ao menor tempo de cozimento e diferença de cor, quando comparados ao BRS Pérola e IAPAR 81. Para BRS Estilo, o aumento na concentração de NaHCO3 reduz significativamente o tempo de cozimento, com menor índice de dano quando comparado ao cultivar BRS Madrepérola. Por fim, com as informações presentes neste trabalho pretende-se contribuir com pesquisas futuras sobre o tema e dessa forma incrementar o consumo do feijão, seja na forma de um produto inovador como o desidratado de cozimento rápido ou na forma de enlatado.
419

Analysis of vegetable oils, seeds and beans by TGA and NMR spectroscopy

Retief, Liezel 03 1900 (has links)
Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Due to the commercial, nutritional and health value of vegetable oils, seeds and beans, the analysis of their components is of much interest. In this dissertation oil-containing food products, specifically vegetable oils, seeds and beans, were investigated. Selected minor components of three locally produced vegetable oils, namely apricot kernel, avocado pear and macadamia nut oils were investigated using 31P NMR spectroscopy. These minor components, including 1,2 diacylglycerols, 1,3 diacylglycerols and free fatty acids, were identified in the 31P NMR spectra of each of the three vegetable oils for the first time. Two approaches were used for the quantification of the minor components present in the spectra. A calibration curve approach used known concentrations of standard minor components to establish calibration curves while a direct correlation approach calculated the unknown concentration of minor components in the vegetable oils using a known amount of standard compound within the analysis solution. These approaches aided in determining the concentration of minor components during storage studies in which vegetable oils were stored in five different ways: exposed to light, in a cupboard, in a cupboard wrapped in tin foil, at -8 °C and at 5 °C. It was found that determining the best storage condition for each oil was difficult since individual minor components were affected differently by the various storage conditions. However, in general the best storage conditions appeared to be 5 °C and -8 °C. The oil, protein and carbohydrate contents of sesame, sunflower, poppy, and pumpkin seeds, and soy, mung, black and kidney beans were analysed by thermogravimetric analysis and 13C NMR solid state NMR spectroscopy. It was shown that the first derivative of TGA data for seeds and beans can give valuable information about the carbohydrate, moisture, protein and fat content. This has not been previously demonstrated. For the seeds, the integration of a region between 270–480 ºC was equal to the sum of the oil and protein content and compared well to quantitative results obtained by other conventional methods. For beans the integration of a region between 180-590 ºC, gave a value which represented the sum of the oil, protein and carbohydrate content. 13C solid state NMR spectroscopy, including SPE-MAS, CP-MAS and variable contact time experiments, was carried out on these seeds and beans and gave valuable information on the solid-like and liquid-like components. To our knowledge these seeds and beans have never been previously analysed using this technique. 13C SPE-MAS NMR spectroscopy indicated that the seeds contained more liquid-like components than the beans. In turn the 13C CP-MAS NMR spectra indicated that beans had higher levels of solid-like components than the seeds. These conclusions correlated well with the quantities of liquid-like components and solid-like components that were determined by conventional methods and TGA. Preliminary studies using T1pH experiments on the components present in the seeds and beans led to a few observations. Most interesting is that a model using a two- phase fit in order to determine T1pH values appears to be more accurate than a one-phase model. / AFRIKAANSE OPSOMMING: Groente olies, sade en bone is ‘n onderwerp van groot belang omrede hul kommersiële, voeding en gesondheidswaardes. In hierdie tesis is olie-bevattende voedselprodukte, spesifiek groente-olies, sade en bone geanaliseer. Geselekteerde komponente teenwoordig in klein hoeveelhede in drie lokaal geproduseerde groente-olies, naamlik appelkoos-pit, avokadopeer en makadamia-neut olies is geanaliseer met behulp van 31P KMR spektroskopie. Hierdie komponente, insluitend 1,2 diasielglyserole, 1,3 diasielglyserole en ongebonde vetsure, is vir die eerste keer geïdentifiseer in die 31P KMR spektra van die drie groente olies. Twee benaderings is gebruik vir die hoeveelheids-bepaling van die komponente in die spektra. ‘n Yking-kurwe metode het gebruik gemaak van bekende hoeveelhede konsentrasies standaard komponente vir die opstel van yking-kurwes, terwyl ‘n direkte korrelasie metode gebruik is om die onbekende konsentrasie van komponente in groente olies te bepaal met behulp van ‘n bekende hoeveelheid standaard verbinding teenwoordig in die oplossing. Hierdie metodes het gelei tot die bepaling van die konsentrasies van die komponente gedurende vyf verskillende berging toestande wat ingesluit het: Blootgestel aan lig, in ‘n donker kas, in ‘n donker kas toegevou in tin foelie, bevries by -8 °C en in ’n koelkas by 5 °C. Dit was bevind dat bepaling van die beste bergingstoestand vir elke olie moeilik is aangesien die individuele komponente verskillend geaffekteer word deur die verskeie berging toestande. Die beste bergings toestand oor die algemeen blyk egter om by 5 °C en -8 °C te wees. Sesamsaad, sonneblomsaad, papawersaad en pampoensaad sowel as sojaboontjie, mungboontjie, swartboontjie en pronkboontjie se olie, protein en koolhidraat komponente was geanaliseer met behulp van termogravimetriese analise (TGA) en 13C soliede toestand KMR spektroskopie. Dit was bevind dat die eerste afgeleide van die TGA data waardevolle inligting lewer oor die komponent inhoud van elk van die sade en bone. Hierdie is nog nie vantevore bevind nie. Vir die sade, was die integrasie van ‘n area tussen 270–480 ºC gelyk aan die som van die olie en proteïen inhoud en het goed vergelyk met die waardes verky deur algemene analitiese metodes. Vir die boontjies, was die integrasie van ‘n area tussen 180-590 ºC gelyk aan die som van die olie, protein en koolhidraat inhoud. 13C vaste staat KMR spektroskopie, insluitende SPE-MAS, CP-MAS en variëerbare kontak-tyd eksperimente, was gedoen en het waardevolle inligting gelewer omtrent die solied-agtige en mobiel-agtige komponente. Hierdie sade en bone is tot ons kennis nog nie van te vore met die tegnieke ondersoek nie. 13C SPE-MAS NMR spektroskopie het aangedui dat daar ‘n groter hoeveelheid mobiel-agtige komponente in sade as in bone teenwoordig is. 13C CP-MAS NMR spektroskopie het weer aangedui dat daar ‘n groter hoeveelheid solied-agtige komponente in bone as in sade teenwoordig is. Hierdie gevolgtrekkings het goed vergelyk met die waarnemings verkry deur konvensionele analitiese metodes en TGA. Voorlopige studies op die komponente van sade en bone deur T1pH eksperimente het tot ‘n paar gevolgtrekkings gelei waarvan die mees interessantste was dat ‘n twee-fase model vir die bepaling van T1pH waardes beter resultate lewer as ‘n een-fase model.
420

Devenir des folates au cours de la transformation des végétaux verts : identification des points clés et des mécanismes / Fate of folates during vegetables processing : identification of key points and mechanisms

Delchier, Nicolas 21 December 2012 (has links)
Les folates sont des vitamines hydrosolubles, impliqués dans la limitation d’apparition de pathologiestelles que les anomalies de fermeture du tube neural. L’homme est dépendant de son alimentation pourcouvrir ses besoins en folates. Les légumes sont une des sources importantes de folates. Dans un mêmetemps, les légumes verts sont principalement consommés à partir de produits transformés, cuits,surgelés ou appertisés. Il est donc important de maitriser les paramètres de la transformation afin depréserver au mieux les teneurs finales en folates. L’objectif de ce travail a donc été d’identifier l’impactdu procédé de transformation (industriel et domestique) sur la perte en folates. Deux procédésindustriels ont été étudiés : la surgélation des épinards et l’appertisation des haricots verts, lestraitements domestiques ont consisté en la cuisson de légume dans de l’eau à ébullition ou à la vapeur.Les traitements thermiques (blanchiment et cuisson vapeur) n’induisent pas de diminutionssignificatives de la concentration en folates. En revanche, des pertes sont observées lorsque les légumessont en contact étroit avec l’eau. Cette étude a permis de mettre à jour deux mécanismes de perte, ladiffusion et la dégradation thermique. La diffusion des folates a été étudiée à l’échelle du laboratoire, lesconstantes de diffusion des folates ont été déterminées. La diffusion est largement influencée par lamatrice elle-même, plus que par la température ou le pH. La part de la dégradation thermique, etnotamment l’oxydation, ne peut être exclue au cours de la diffusion. C’est pourquoi des cinétiques dedégradation ont été réalisées à différentes température et différentes teneurs en oxygène, à partir depurées d’épinards et de haricots verts ainsi que sur des solutions modèles. L’oxygène joue un rôleimportant dans la dégradation chimique, notamment dans les solutions modèle. Les matrices végétalesconstituraient donc une barrière à l’oxydation des folates. Les folates sont globalement assez bienconservés au cours du procédé de transformation. Une des pistes de recherche qui prendrait un sens dansla continuité de ce travail serait l’étude de l’impact des procédés de transformation sur labioaccessibilité des folates / Folates are water-soluble vitamins, involved in the limitation of diseases such as neural tube defects.Man is dependent on his food to cover its folates’ needs. Fruits and vegetables, particularly greenvegetables are one of the major dietary sources of folates. In the same time, green vegetables are mainlyconsumed as processed products, cooked frozen or canned. It is therefore important to controlprocessing parameters in order to preserve folates content in final products. The aim of this study was toidentify the impact of processing (industrial and domestic) on folates loss. Two industrial processingchains were studied: spinach freezing chain and green beans canning chain, home treatments consistedin vegetables boiling or steaming. Thermal treatments (blanching and steaming) did not induce asignificant decrease in folates concentrations. In contrast, losses were observed when vegetables were inclose contact with the water. This study identifies two mechanisms of losses, leaching and thermaldegradation. Folates diffusion was studied on a laboratory scale, the diffusion constants for folates weredetermined. Diffusion was more influenced by the matrix, than by temperature or pH. Some of thermaldegradation, including oxidation, can not be excluded during leaching experiments. Degradationkinetics were performed at different temperature, with different oxygen contents, from spinach andgreen beans puree as well as model solutions. Oxygen plays an important role in chemical degradation,especially in model solutions. Plant matrix seemed to have protective effect, maybe as a barrier tooxygen. Folates are generally fairly well preserved during processing. One of the perspectives would bethe study of the impact of processing on folates bioaccessibility

Page generated in 0.0777 seconds