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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

Development and application of an HPLC-MS/MS method for the characterization and quantification of a-retinyl esters and vitamin A in human plasma after consumption of a-carotene

Goetz, Hilary Jane January 2014 (has links)
No description available.
12

Carotenóides da batata-doce (Ipomoea batatas Lam.) e sua relação com a cor das raízes / Carotenoids from sweet potatoes (Ipomoea batatas Lam.) and its relationship with their color

Muradian, Ligia Bicudo de Almeida 11 September 1991 (has links)
Com o objetivo de determinar os parâmetros de cor e carotenóides, assim como as mudanças no teor pró-vitamínico A de batatas-doces cruas e cozidas, foram analisados cultivares desta raiz procedentes do Instituto Agronômico de Campinas e do Centro Nacional de Pesquisa de Hortaliças da EMBRAPA de Brasília. Foram identificados sete carotenóides na análise de batatas-doces, a saber: 5,6,5\',6\'-diepoxi-β-caroteno; 5,6-monoepoxi-β-caroteno; β-caroteno; luteocromo; α-zeacaroteno; β-zeacaroteno e aurocromo. O β-caroteno foi o principal carotenóide nos cultivares Centennial(148,81 J-Ig/g de batata-doce crua), Heart Gold (51,79 µg/g), Anápolis (14,24 µg/g), Acadian (218,15 µg/g), Morada Inta (10,61 µg/g), Vineland Bush (22,60 µg/g) e clone CNPH (4,87 µg/g).O luteocromo foi o principal carotenóide nos cultivares Monalisa (1,55 J-Ig/g de batata-doce crua), IAC-2-71 (0,77 J-Ig/g) e SRT-252 (0,92 µg/g). Com relação as raízes cruas, os valores de vitamina A variaram de 1 equivalente de retinol/100g para o cultivar IAC-2-71 até 3.703 equivalentes de retinol /100g para cultivar Acadian. Para as raízes cozidas o cultivar apresentou maior atividade pró-vitamínica A foi o Acadian com 4021 equivalentes de retinol/100g. A perda de β-caroteno pelo cozimento variou de 4,5% a 42,6% conforme o cultivar. Os parâmetros de cor (L Hunter, a Hunter, b Hunter, croma e ângulo do tom) não diferiram para os três cortes transversais das raízes (parte superior, central e inferior). Quanto ao cozimento, houve diminuição significativa dos parâmetros L Hunter (luminosidade), +a Hunter (vermelho) e aumento nos parâmetros -a Hunter (verde) e ângulo do tom. O parâmetro b Hunter (amarelo) e croma diminuíram pelo cozimento nos cultivares Centennial, SRT-252, Monalisa e Heart gold. Foram obtidas boas correlações do logaritmo neperiano dos carotenóides totais com os parâmetros de cor. A melhor correlação foi com Lab (R2= 0,9944) para a batata-doce crua e Lab (R2= 0,9936) para a batata-doce cozida. As equações para se estimar o teor de . carotenóides através dos parâmetros de cor foram: c (µg/g/ ) e(-1.2051 + 0,01075a + 0,1013b) para a batata doce crua e C (µg/g) = e (3,1094 - 0,0476L + 0,1164a + 0,0667b) para a batata-doce cozida. / With the purpose of determining the color and carotenoid parameters,as well as the changes in the provitamin A value of sweet potatoes raw and cooked, ten cultivars from \"Instituto Agronômico de Campinas\" and \"Centro Nacional de Pesquisa de Hortaliças da EMBRAPA de Brasilia\" were analysed. Seven carotenoids were identified in the sweet potatoes analysis, as follows: 5.6.5\' ,6\'- β-carotene-diepoxide; 5,6-β- carotene epoxide; β-carotene; luteochrome; µ-zeacarotene; β-azeacarotene and aurochrome. β-carotene was the main carotenoid of the followinq cultivars: Centennial (148.81 ~g/g of sweet potato); Heart Gold (51. 79 µg/g); Anapolis (14.24 µg/g); Acadian (218,15 µg/g) ; Morada Inta (10.61 µg/g); Vineland Bush (22.60 µg/g) clone CNPH (4.87 µg/g). Luteochrome was the main carotenoid of Monalisa (1.55 µg/g of raw sweet potato), IAC-2-71 (0.77 µg/g) and SRT-252 (0.92 µg/g) cultivars. For raw roots-the vitamin A values varied from 1 retinol equivalent/l00q for IAC-2-71 cultivar up to 3,703 retinol equivalents/l00g for Acadian cultivar. For cooked roots Acadian cultivar was the one that presented more provitamin A activity, with 4,021 retinol equivalent/100g. The loss of β-carotene due to cooking varied from 4.51% to 42.6%, in accordance with the kind of cultivar. The color parameters (L Hunter-, a Hunter-, b Hunter-, chroma and hue angle) did not show any change for the three transversal cuts in the root (top, middle and bottom). Regarding cooking, there were significant decreases in the parameters L Hunter(luminosity) and +a Hunter (red) and an increase of -a Hunter (green) and hue angle parameters. The b Hunter parameter (yellow) and chroma decreased due to cooking in the Centennial, SRT-252, Monalisa and Heart Gold cultivars. There were obtained good correlations of total carotenoid neperiane logarithim with the color parameters. The best correlation was with \"Lab\" (R2= 0,9944) for- r-aw sweet potato and \"Lab\" (R2= 0,9936) for cooked sweet potato. The equation used to estimate carotenoids value through color parameters was the following: C (µg/g) = e(- 1,2051 + 0,01075a + 0,1013b) for raw sweet potato and C (&#181g/g = e(3,1094 - 0,0476L + 0,1164a + 0,0667b) for cooked sweet potato.
13

Carotenóides da batata-doce (Ipomoea batatas Lam.) e sua relação com a cor das raízes / Carotenoids from sweet potatoes (Ipomoea batatas Lam.) and its relationship with their color

Ligia Bicudo de Almeida Muradian 11 September 1991 (has links)
Com o objetivo de determinar os parâmetros de cor e carotenóides, assim como as mudanças no teor pró-vitamínico A de batatas-doces cruas e cozidas, foram analisados cultivares desta raiz procedentes do Instituto Agronômico de Campinas e do Centro Nacional de Pesquisa de Hortaliças da EMBRAPA de Brasília. Foram identificados sete carotenóides na análise de batatas-doces, a saber: 5,6,5\',6\'-diepoxi-β-caroteno; 5,6-monoepoxi-β-caroteno; β-caroteno; luteocromo; α-zeacaroteno; β-zeacaroteno e aurocromo. O β-caroteno foi o principal carotenóide nos cultivares Centennial(148,81 J-Ig/g de batata-doce crua), Heart Gold (51,79 µg/g), Anápolis (14,24 µg/g), Acadian (218,15 µg/g), Morada Inta (10,61 µg/g), Vineland Bush (22,60 µg/g) e clone CNPH (4,87 µg/g).O luteocromo foi o principal carotenóide nos cultivares Monalisa (1,55 J-Ig/g de batata-doce crua), IAC-2-71 (0,77 J-Ig/g) e SRT-252 (0,92 µg/g). Com relação as raízes cruas, os valores de vitamina A variaram de 1 equivalente de retinol/100g para o cultivar IAC-2-71 até 3.703 equivalentes de retinol /100g para cultivar Acadian. Para as raízes cozidas o cultivar apresentou maior atividade pró-vitamínica A foi o Acadian com 4021 equivalentes de retinol/100g. A perda de β-caroteno pelo cozimento variou de 4,5% a 42,6% conforme o cultivar. Os parâmetros de cor (L Hunter, a Hunter, b Hunter, croma e ângulo do tom) não diferiram para os três cortes transversais das raízes (parte superior, central e inferior). Quanto ao cozimento, houve diminuição significativa dos parâmetros L Hunter (luminosidade), +a Hunter (vermelho) e aumento nos parâmetros -a Hunter (verde) e ângulo do tom. O parâmetro b Hunter (amarelo) e croma diminuíram pelo cozimento nos cultivares Centennial, SRT-252, Monalisa e Heart gold. Foram obtidas boas correlações do logaritmo neperiano dos carotenóides totais com os parâmetros de cor. A melhor correlação foi com Lab (R2= 0,9944) para a batata-doce crua e Lab (R2= 0,9936) para a batata-doce cozida. As equações para se estimar o teor de . carotenóides através dos parâmetros de cor foram: c (µg/g/ ) e(-1.2051 + 0,01075a + 0,1013b) para a batata doce crua e C (µg/g) = e (3,1094 - 0,0476L + 0,1164a + 0,0667b) para a batata-doce cozida. / With the purpose of determining the color and carotenoid parameters,as well as the changes in the provitamin A value of sweet potatoes raw and cooked, ten cultivars from \"Instituto Agronômico de Campinas\" and \"Centro Nacional de Pesquisa de Hortaliças da EMBRAPA de Brasilia\" were analysed. Seven carotenoids were identified in the sweet potatoes analysis, as follows: 5.6.5\' ,6\'- β-carotene-diepoxide; 5,6-β- carotene epoxide; β-carotene; luteochrome; µ-zeacarotene; β-azeacarotene and aurochrome. β-carotene was the main carotenoid of the followinq cultivars: Centennial (148.81 ~g/g of sweet potato); Heart Gold (51. 79 µg/g); Anapolis (14.24 µg/g); Acadian (218,15 µg/g) ; Morada Inta (10.61 µg/g); Vineland Bush (22.60 µg/g) clone CNPH (4.87 µg/g). Luteochrome was the main carotenoid of Monalisa (1.55 µg/g of raw sweet potato), IAC-2-71 (0.77 µg/g) and SRT-252 (0.92 µg/g) cultivars. For raw roots-the vitamin A values varied from 1 retinol equivalent/l00q for IAC-2-71 cultivar up to 3,703 retinol equivalents/l00g for Acadian cultivar. For cooked roots Acadian cultivar was the one that presented more provitamin A activity, with 4,021 retinol equivalent/100g. The loss of β-carotene due to cooking varied from 4.51% to 42.6%, in accordance with the kind of cultivar. The color parameters (L Hunter-, a Hunter-, b Hunter-, chroma and hue angle) did not show any change for the three transversal cuts in the root (top, middle and bottom). Regarding cooking, there were significant decreases in the parameters L Hunter(luminosity) and +a Hunter (red) and an increase of -a Hunter (green) and hue angle parameters. The b Hunter parameter (yellow) and chroma decreased due to cooking in the Centennial, SRT-252, Monalisa and Heart Gold cultivars. There were obtained good correlations of total carotenoid neperiane logarithim with the color parameters. The best correlation was with \"Lab\" (R2= 0,9944) for- r-aw sweet potato and \"Lab\" (R2= 0,9936) for cooked sweet potato. The equation used to estimate carotenoids value through color parameters was the following: C (µg/g) = e(- 1,2051 + 0,01075a + 0,1013b) for raw sweet potato and C (&#181g/g = e(3,1094 - 0,0476L + 0,1164a + 0,0667b) for cooked sweet potato.
14

POST HARVEST STORAGE OF BIOFORTIFIED MAIZE IN PURDUE IMPROVED CROP STORAGE (PICS) BAGS AND EFFECT ON SUBSEQUENT FLOUR RHEOLOGY AND CAROTENOID BIOACCESSIBILITY

Smith G Nkhata (6668768) 15 August 2019 (has links)
<p>Successful adoption of biofortified orange maize in developing countries requires careful consideration of factors across the chain from farm to fork. This includes consideration of post-harvest storage conditions optimal for the retention of both proviatamin A carotenoids and cooking quality critical to consumers. In these considerations, identification of economical storage methods is critical considering the limitations within specific countries that biofortified maize is being disseminated. To address these points, this dissertation research focused on evaluation of the utility of the Purdue Improved Crop Storage (PICS) bags as a post-harvest storage solution for biofortified maize. The specific focus of this research was to monitor retention of provitamin A and other carotenoids in two biofortified maize genotypes (OPVI and OPVII) as well as storage effect on flour functionality. Finally, a preliminary assessment of the impacts of storage on carotenoid bioaccessibility was completed to begin to translate findings to practice.</p><p>Maize grain from 2016 harvest was stored at ambient conditions for eight months in either PICS bags with or without an O<sub>2</sub> scavenger, (PICS-oxy) and (PICS-noxy), respectively and compared to storage in common polypropylene woven bags (control). After 4 months of storage carotenoid content was significantly higher (p<0.05) in PICS-oxy compared to PICS-noxy and woven bags demonstrating the importance of entrapped oxygen on maize carotenoid degradation. Furthermore, differences in carotenoid stability between maize genotypes were observed with OPVI having higher retention than OPVII. After 8 months, carotenoid retention remained dependent on storage bag and genotype with retention being greater in PICS-oxy and PICS-noxy compared to woven bags. However, final levels after 8 months were more similar between storage methods. Overall, oxygen content and genotype were found to be determining factors in the effectiveness of PICS to mitigate carotenoid degradation during post-harvest storage of maize.</p><p>While reducing the rate of carotenoid degradation during postharvest storage of biofortified maize is important, success of biofortified maize is also dependent on consumer adoption of these grains and their performance in traditional food preparation. Assessment of the rheological and functional properties of these two biofortified maize genotypes as a function of post-harvest storage was completed to assess the impact of post-harvest storage in PICS bags on flour functionality and rheological properties for the two biofortified orange maize genotypes and a control white maize genotype. Flour pasting profiles were assessed initially and at 4 and 8 months. After 8 month storage in woven and PICS bag, OPVI and OPVII produced porridges with similar viscosities to their initial viscosities regardless of postharvest storage type. White maize viscosities progressively decreased with storage and were significantly lower (p<0.05) in woven compared to PICS storage. Sequestration of oxygen (PICS-oxy) had modest but significant effects (p<0.05) on key pasting parameters including peak and final viscosities. These results suggest that oxygen sequestration has a critical effect on final flour functionality. DTT treatment partially restored flour pasting profiles suggesting disulfide linkages may modify pasting profiles of flour. There was also an increase in free ferrulic and <i>p</i>-coumaric acids during storage which may have contributed to observed decreases in porridge viscosities. Evidence of this was found through Raman spectroscopy with spectral intensity at both 478cm<sup>-1</sup> and 2911cm<sup>-1</sup> decreasing with storage suggesting the potential for structural changes induced by storage on starch polymer. While storage in PICS bags does not seem to adversely affect flour functionality it may provide some additional economic benefit resulting from requiring proportionally less flour to achieve similar final viscosities as flour from woven bag stored grains. </p><p>Finally, the effect of postharvest storage on bioaccessibility of carotenoids was explored using experimental wet cooked porridges made from ‘fresh’ and stored grains using an established three stage in-<i>vitro</i> digestion model. Relative carotenoid bioaccessibility (% micellarization) was generally higher in less viscous porridge made from grains stored in woven bags compared to porridge from initial or PICS bags stored grains suggesting that higher viscosity might partly explain lower relative bioaccessibility in porridge from grains stored in PICS bags. Absolute carotenoid bioaccessibility from experimental porridge was dependent on carotenoid species and storage system. Extrapolation of relative bioaccessibility (%) to absolute bioaccessibility (µg/g flour) suggests that fresh grains and their corresponding porridges would provide more absolute bioaccessible carotenoids compared to stored grains despite some improvement in relative accessibility. As such, storage losses remain the main factor impacting total available carotenoids and should continue to be an area of focus for future mitigation. With the potential to minimize post-harvest losses, improve carotenoid retention and provide a product with improved cooking performance, PICS bags do appear to offer a viable storage alternative to improve both food and nutrition security in developing countries.</p><p></p>
15

The investigation of different levels of vitamin A and its effects on animal performance, carcass traits, and the conversion rate of external fat color in cull-cows.

Parkinson, Jake T. January 2020 (has links)
No description available.
16

Naturally occurring variation in the promoter of the chromoplast-specific Cyc-B gene in tomato can be used to modulate levels of ß-carotene in ripe tomato fruit

Orchard, Caleb January 2014 (has links)
No description available.

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