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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.
61

Efficacy of herbicide spray droplet size, flooding period, and seed burial depth on Palmer amaranth (Amaranthus palmeri S. Wats.) control

Franca, Lucas Xavier 03 May 2019 (has links)
The continued spread of Palmer amaranth (Amaranthus palmeri S. Wats.) throughout the southern and midwestern United States is a result of herbicide-resistant populations. Besides being the most troublesome weed specie in several agronomic crops, Palmer amaranth is also host to economically important pests such as tarnished plant bug (Lygus lineolaris Palisot de Beauvois). Pesticide application methodology that maximizes efficacy while reducing selection pressure is needed to combat herbicide-resistant Palmer amaranth. Pulse width modulation (PWM) sprayers are used for pesticide application with the goal of maintaining product efficacy while mitigating spray drift. Additionally, alternative off-season weed management practices such as flooding could be adopted to optimize soil seedbank depletion. Therefore, evaluation of spray droplet size and flooding period on Palmer amaranth control and seed germination was conducted. The objectives of this research were to: (1) evaluate the influence of spray droplet size on lactofen and acifluorfen efficacy on Palmer amaranth using a PWM sprayer, (2) develop prediction models to determine spray droplet size that provides the greatest level of Palmer amaranth control, (3) evaluate the impact of flooding period and seed burial depth on Palmer amaranth seed germination in different soil textures, and (4) analyze the impact of nitrogen fertilizer application rate on the attractiveness of Palmer amaranth to tarnished plant bug. Results show that spray droplet size does not affect lactofen efficacy on Palmer amaranth, thus, coarser spray droplets are recommended to increase spray drift mitigation efforts. In contrast, acifluorfen applied with 300 μm (medium) spray droplets provided the greatest Palmer amaranth control. Furthermore, prediction models indicated that greater model accuracy was obtained when adopting a location-specific weed management approach. Flooding periods of 3, 4, and 5 months reduced Palmer amaranth seed germination across burial depths and soil textures. Therefore, fall-winter flooding may be adopted as an effective practice for soil seedbank depletion. Results also demonstrated that nitrogen fertilizer application rate does not consistently impact Palmer amaranth attractiveness to tarnished plant bug.
62

Application of Genome Reduction, Next Generation Sequencing, and KASPar Genotyping in Development, Characterization, and Linkage Mapping of Single Nucleotide Polymorphisms in the Grain Amaranths and Quinoa

Smith, Scott Matthew 13 March 2013 (has links) (PDF)
The grain amaranths (Amaranthus sp.) and quinoa (Chenopodium quinoa Willd.) are important seed crops in South America. These crops have gained international attention in recent years for their nutritional quality and tolerance to abiotic stress. We report the identification and development of functional single nucleotide polymorphism (SNP) assays for both amaranth and quinoa. SNPs were identified using a genome reduction protocol and next generation sequencing. SNP assays are based on KASPar genotyping chemistry and were detected using the Fluidigm dynamic array platform. A diversity screen consisting of 41 amaranth accessions showed that the minor allele frequency (MAF) of the amaranth markers ranged from 0.05 to 0.5 with an average MAF of 0.27. A diversity screen of 113 quinoa accessions showed that the MAF of the quinoa markers ranged from 0.02 to 0.5 with an average MAF of 0.28. Linkage mapping in amaranth produced a linkage map consisting of 16 linkage groups, presumably corresponding to each of the 16 amaranth haploid chromosomes. This map spans 1288 cM with an average marker density of 3.1 cM per marker. Linkage mapping in quinoa resulted in a linkage map consisting of 29 linkage groups with 20 large linkage groups, spanning 1,404 cM with a marker density of 3.1 cM per SNP marker. The SNPs identified here represent important genomic tools needed for genetic dissection of agronomically important characteristics and advanced genetic analysis of agronomic traits in amaranth and quinoa. We also describe in detail the scalable and cost effective SNP genotyping method used in this research. This method is based on KBioscience's competitive allele specific PCR amplification of target sequences and endpoint fluorescence genotyping (KASPar) using a FRET capable plate reader or Fluidigm's dynamic array high throughput platform.
63

Integrating weed-suppressive cotton chromosome substitution lines and cover crops for sustainable weed management in cotton production systems.

Miller, Alyssa Lea 08 August 2023 (has links) (PDF)
Weeds pose a challenge to cotton production, and herbicides have been the primary means of control. However, there is growing concern over weed resistance to herbicides. To address this issue, we evaluated three cover crop species and six cotton accessions for weed suppression. The study found that hairy vetch, wheat, and B16 cotton CS line effectively suppressed Amaranthus species, while MNTN 4-15, B16, hairy vetch, and wheat were correlated with the highest cotton yield. Cover crops were also analyzed for chlorogenic acid content, with wheat, MNTN 4-15, and hairy vetch producing the highest amounts. The greenhouse tray study showed that wheat and hairy vetch cover crops were among the best treatments for weed suppression. These findings suggest that cover crops may provide effective weed control and improve crop yield.
64

Evaluation of integrated weed management techniques and their nuances in Virginia crop production

Beam, Shawn Christopher 04 November 2019 (has links)
Herbicide resistant weeds are driving implementation of integrated weed management (IWM). A new tactic to manage weeds is harvest weed seed control (HWSC), which targets weed seeds retained on the plant at crop harvest and either destroys, removes, or concentrates them. Research is limited on the effectiveness of HWSC in US cropping systems. For HWSC to be effective it is important to know when and how many seed are shed from a weed species in relation to crop harvest. Research was conducted to quantify when weed seed are shattered from 6 economically important weed species, four broadleaf (redroot pigweed, common ragweed, common lambsquarters, and common cocklebur) and two grass species (large crabgrass and giant foxtail). Results indicate that among summer annuals, broadleaf species retain larger proportions of their seed compared to grass species at the first opportunity for soybean harvest. As harvest was delayed, more seeds shattered from all species evaluated, indicating timely harvest is critical to maximizing HWSC effectiveness. Studies were conducted on grower fields in Virginia to evaluate the effectiveness of HWSC (field residue and weed seed removal). Results indicate that HWSC can significantly reduce populations of Italian ryegrass in wheat and common ragweed in soybean in the next growing season, but reductions were not observed for Palmer amaranth in soybean. Investigating IWM system for common ragweed control in soybean, HWSC was found to be less effective than soybean planting date (i.e. double cropping after wheat) at reducing common ragweed populations. However, the effectiveness of HWSC varied by location. If HWSC adoption were to become widespread, weeds could adapt by shedding seed earlier in the season. Research was conducted by growing Palmer amaranth populations from across the eastern US in a common garden. Currently there are differences in flowering time and seed shatter among Palmer amaranth populations based on the location of the maternal population, indicating potential for adaptation. This research demonstrates that HWSC is a viable option for weed management in US cropping systems but needs to be stewarded like any other weed management tool. / Doctor of Philosophy / Herbicide resistance in weeds is a growing problem in the US and around the world. Alternative methods of weed control must be adopted to maintain crop yields in the presence of herbicide-resistant weeds. Researchers and extension specialists strongly advise growers to adopt an integrated weed management (IWM) approach. Integrated weed management involves implementing multiple weed control tactics during a growing season. By using multiple methods of weed control within a given season the chances of weeds becoming resistant or adapting to any single tactic is reduced. Harvest weed seed control (HWSC) is a new tactic developed in Australia in response to herbicide resistance. HWSC targets weed seeds retained on the plant at crop harvest. In a normal crop harvest, the combine removes the grain and spreads crop residues (leaves, stalks, and other plant parts), including weed seeds, back across the field. When HWSC is implemented, weed seeds are destroyed (narrow windrow burning, cage mills) or concentrated and potentially removed from the field (chaff carts, direct bale, chaff lining). Thus, HWSC limits the number of weed seeds returned to the soil seed bank. There is limited research on HWSC and its integration with other tactics, in US cropping systems. For HWSC to be effective it is necessary for weed seeds to be retained on the mother plant in sufficient quantities at crop harvest. Research was conducted in Virginia to determine when weed seeds are shattered during the soybean growing season for 6 economically important weed species, four broadleaf (redroot pigweed, common ragweed, common lambsquarters, and common cocklebur) and two grass species (large crabgrass and giant foxtail). The broadleaf species retained >85% of their seed until the first opportunity for soybean harvest (mid-October). In the grass species, more seed shattered prior to soybean harvest with 50% of large crabgrass and 74% of giant foxtail seed being retained at the first opportunity for soybean harvest. When harvest was delayed seed continued to shatter and less was captured using HWSC. This research indicates broadleaf species are more suitable candidates for HWSC than grass species, among summer annuals. Further research on the ability of seed to germinate in relation to when seeds were shed was conducted on redroot pigweed, common ragweed and common lambsquarters. Results indicate that there are variable effects on germination of these species depending on when they were shed. HWSC was implemented on grower fields to assess the impact on weed populations of 3 weed species (Italian ryegrass, common ragweed, and Palmer amaranth). These experiments compared conventional harvest and HWSC (field residue and weed seed removal) when all other management strategies were the same within that field. Italian ryegrass tiller density in wheat varied by location but was reduced up to 69% in the spring following implementation of HWSC. By wheat harvest, HWSC reduced Italian ryegrass seed head density 67% at one location compared to conventional harvest. In soybean, common ragweed densities were reduced by 22 and 26% prior to field preparation and postemergence herbicide applications, respectively, in the HWSC plots compared to the conventional harvest plots. No differences were observed in common ragweed density by soybean harvest. No differences were observed with Palmer amaranth densities at any point during the soybean growing season. This research show that HWSC can reduce weed populations but is variable and additional research is still needed. IWM experiments were established across Virginia to compare soybean planting date (full season or double cropped), + cover crop (cereal rye/wheat or no cover), and + HWSC (field residue removal) to evaluate the best management strategy for common ragweed in soybean. Across all locations, double cropping soybean behind wheat had the greatest impact on common ragweed densities at the end of the first season. The impact of double cropping soybeans on common ragweed population is due to the emergence pattern of common ragweed; majority of common ragweed emerges prior to planting double cropped soybean (mid-June to early-July). HWSC was variable and only reduced common ragweed density at one of three locations. Widespread adoption of HWSC could place a selection pressure on weeds to shatter seed earlier in the season. A common garden experiment was conducted in Blacksburg, VA to assess Palmer amaranth populations collected from central Florida to southern Pennsylvania for differences in flowering time, time to seed shatter, and other phenotypic traits. Results indicate that latitude of the maternal population influences time to first flower with a 0.53 d reduction in flowering time for every degree north in latitude the maternal population was collected from. The strongest predictor of Palmer amaranth flowering time was emergence date/daylength. For every day emergence was delayed the time to first flower was reduced by 0.31 and 0.24 d for female and male plants, respectively. Time from emergence or first flower to first seed shatter was reduced by 0.48 or 0.17 d, respectively, for each day emergence was delayed. These results indicate that differences exist currently among Palmer amaranth populations and the selection pressure of HWSC could push these populations to flower and shatter seed early.
65

Characterisation of Amaranthus Tricolor mutant plants with increased drought-tolerance

Kgang, Itumeleng Eugenia 02 1900 (has links)
M. Tech. (Biotechnology, Department of Health Sciences), Vaal University of Technology / Amaranthus tricolor (A. tricolor) is a nutritious vegetable crop that is used as a subsistence and cash crop in the rural areas in Africa. Its yield and production is severely limited by abiotic stresses such as drought. Mutation technology, using gamma irradiation, was previously employed as a tool to create genetic variation in order to select for lines with improved drought-tolerance. During irradiation, 160 Gy (Gray) was selected as the optimal dosimetry that allowed subsequent seed germination. The resulting mutant lines were screened over several generations under field and greenhouse conditions and seven promising drought-tolerant lines were selected. Here we report on physiological and morphological studies of two of these Amaranthus mutant lines (#2 and #5) to confirm the enganced drought-tolerance. Plants were grown in the greenhouse in plastic pots containing germination mix with fertiliser. They were exposed to 21 days of well-watered condition, 19 days of drought-stress conditions and 7 days of re-watering. shoot height, leaf area, protein content and relative water content (RWC) of the fresh and dry material were determined colorimetrically under well-watered and drought-stress conditions, while anthocyanin was only measured during well-watered conditions. Shoot height, leaf area, number of leaves per plant and the protein content were significantly reduced under water-stress conditions. Under well-watered condition mutant #5 grew faster with the shoot length significantly higher than mutant #2 and the wild type. Even though drought adversely affected shoot lenght, mutant#5 still performed better than mutant #2 and the wild type under drought-stress conditions. While under both well-watered and drought-stress conditions, the wild type plants had bigger leaf area compared to the two mutant lines. After 16 days of drought-stress conditions, all the leaves of the wild type plants were dried out, as a result no wild type plants recovered after 8 days re-watering. Meanwhile, both mutant #2 and #5 plants recovered significantly after 8 days of re-watering. The wild type was tolerant compared to the two mutant lines. Protein content for mutant #2 plants was higher under both well-watered and drought-stress conditions but was not significantly different from mutant #5 plants compared to the wild type plants after 19 days of drought-stress conditions. Furthermore, genetic diversity was examined in all the Amaranthus lines using random amplified polymorphic DNA (RAPD) analysis. Nineteen arbitrary RAPD markers were used of which two detected polymorphisms (OPA) 07 and OPA 16).
66

Efeito da proteína de amaranto (Amaranthus cruentus L. BRS Alegria) na atividade enzimática hepática da HMG-CoA redutase e seu papel no metabolismo lipídico em hamsters / Effect of amaranth (Amaranthus cruentus L. BRS Alegria) protein in hepatic enzymatic activity of HMG-CoA reductase and its role in lipid metabolism in hamsters

Suraty, Thaís Rezende 30 January 2013 (has links)
Introdução: Atualmente as Doenças Crônicas não Transmissíveis (DCNTs) são um dos maiores problemas de saúde pública da sociedade. É bastante claro o papel da dieta no controle do colesterol e na incidência de doenças cardiovasculares. Neste sentido, o amaranto desperta grande interesse devido a sua propriedade hipocolesterolemizante. Estudos sugerem que seu efeito hipocolesterolemizante está associado à inibição da enzima HMG-CoA redutase, chave na síntese do colesterol endógeno. Objetivo: Avaliar a atividade enzimática hepática da HMG-CoA redutase de hamsters alimentados com proteína de amaranto. Metodologia: Trinta hamsters foram divididos em 5 grupos e receberam dieta diferenciadas pela fonte protéica. Os grupos I e Icol receberam dieta com 20% de proteína de amaranto e os grupos caseína C e Ccol receberam dieta com 20% de caseína. Os grupos \"col\" apresentavam dieta com 0,1% de colesterol e 13,5% de gordura de coco. O metabolismo lipídico foi acompanhado através do monitoramento das concentrações plasmáticas de colesterol total, triacilgliceróis, HDL, e fração não-HDL nos animais. A excreção de colesterol e ácidos biliares foram quantificados nas fezes dos animais e o grau de esteatose hepática foi determinada através de análises histológicas do lobo direito do fígado. A atividade da enzima HMGR nos fígados foi medida por meio do Kit CS 1090 da Sigma-Aldrich com adaptações segundo Cong et al, 2012. A análise é baseada em espectrometria com absorbância de 340nm a 37ºC, que representa a oxidação de NADPH pela HMG-CoA redutase, na presença do substrato HMG-CoA. Conclusões: A proteína de amaranto pode ser considerado um aliado na redução dos agravos gerados pela dislipidemia, uma vez que reduziu significativamente os níveis de colesterol plasmático e gordura hepática, além de ser demonstrado seu efeito na redução da atividade da enzima HMG-CoA redutase dos animais hipercolesterolemizados que se alimentaram com proteína de amaranto. Uma vez verificado o efeito hipocolesterolemizante e seu possível mecanismo de ação por meio da enzima HMG-CoA redutase, espera-se com isso, estimular o consumo pela população brasileira produção de amaranto no Brasil, como alternativa para diversificar a dieta e a agricultura. / Introduction: Nowadays, Non-Communicable Chronic Diseases (NCCD) are a major challenge in health public. It is evident the role of diet in the control of cholesterol and incidence of cardiovascular disease. In this sense, amaranth arouses great interest due to its hypocholesterolemic property. Studies suggest that amaranth\'s hypocholesterolemic effect is associated with the inhibition of the enzyme HMG-CoA reductase, known as the key process to the endogenous cholesterol synthesis. Objective: Evaluate the hepatic enzymatic activity of HMG-CoA reductase in hamsters fed with amaranth protein. Methodology: Amaranth protein was isolated according to the conventional isoelectric precipitation methodology. Thirty hamsters were divided in 5 groups and were fed diets with different protein source. Experimental groups (I and lcol) had a diet containing 20% of protein amaranth and control groups(C and Cool) received a diet with 20% of casein. Moreover, groups \"col\" had also a diet with 0.1% cholesterol and 13.5% coconut oil in their composition. The lipid metabolism was accompanied through monitoring of plasma concentrations of total cholesterol, triglycerides, HDL and non-HDL fraction in animals. Excretion of cholesterol and bile acids were quantified in the feces of animals and the degree of hepatic steatosis was determined by histological analysis of the liver\'s right lobe. The HMGR enzyme activity in the liver was measured by the CS 1090 Kit from Sigma-Aldrich adjusted in accordance with Cong et al, 2012. The analysis is based on spectrometry with absorbance of 340nm at 37 ° C, which represents the oxidation of NADPH by HMG-CoA reductase in the presence of HMG-CoA substrate. Conclusions: Amaranth protein can be considered as an ally in reducing of injuries generated by dyslipidemia, since it significantly reduced levels of plasma cholesterol and hepatic fat. Furthermore, it was demonstrated its effect on reducing activity of HMG-CoA reductase enzyme in hypercholesterolemic animals, which were fed with amaranth protein. Therefore, once verified the hypocholesterolemic effect of amaranth and its possible action mechanism through HMG-CoA reductase enzyme, stimuli on the production of amaranth are expected as an alternative to diversify the diet and agriculture.
67

Efeito da proteína de amaranto (Amaranthus cruentus L. BRS Alegria) na atividade enzimática hepática da HMG-CoA redutase e seu papel no metabolismo lipídico em hamsters / Effect of amaranth (Amaranthus cruentus L. BRS Alegria) protein in hepatic enzymatic activity of HMG-CoA reductase and its role in lipid metabolism in hamsters

Thaís Rezende Suraty 30 January 2013 (has links)
Introdução: Atualmente as Doenças Crônicas não Transmissíveis (DCNTs) são um dos maiores problemas de saúde pública da sociedade. É bastante claro o papel da dieta no controle do colesterol e na incidência de doenças cardiovasculares. Neste sentido, o amaranto desperta grande interesse devido a sua propriedade hipocolesterolemizante. Estudos sugerem que seu efeito hipocolesterolemizante está associado à inibição da enzima HMG-CoA redutase, chave na síntese do colesterol endógeno. Objetivo: Avaliar a atividade enzimática hepática da HMG-CoA redutase de hamsters alimentados com proteína de amaranto. Metodologia: Trinta hamsters foram divididos em 5 grupos e receberam dieta diferenciadas pela fonte protéica. Os grupos I e Icol receberam dieta com 20% de proteína de amaranto e os grupos caseína C e Ccol receberam dieta com 20% de caseína. Os grupos \"col\" apresentavam dieta com 0,1% de colesterol e 13,5% de gordura de coco. O metabolismo lipídico foi acompanhado através do monitoramento das concentrações plasmáticas de colesterol total, triacilgliceróis, HDL, e fração não-HDL nos animais. A excreção de colesterol e ácidos biliares foram quantificados nas fezes dos animais e o grau de esteatose hepática foi determinada através de análises histológicas do lobo direito do fígado. A atividade da enzima HMGR nos fígados foi medida por meio do Kit CS 1090 da Sigma-Aldrich com adaptações segundo Cong et al, 2012. A análise é baseada em espectrometria com absorbância de 340nm a 37ºC, que representa a oxidação de NADPH pela HMG-CoA redutase, na presença do substrato HMG-CoA. Conclusões: A proteína de amaranto pode ser considerado um aliado na redução dos agravos gerados pela dislipidemia, uma vez que reduziu significativamente os níveis de colesterol plasmático e gordura hepática, além de ser demonstrado seu efeito na redução da atividade da enzima HMG-CoA redutase dos animais hipercolesterolemizados que se alimentaram com proteína de amaranto. Uma vez verificado o efeito hipocolesterolemizante e seu possível mecanismo de ação por meio da enzima HMG-CoA redutase, espera-se com isso, estimular o consumo pela população brasileira produção de amaranto no Brasil, como alternativa para diversificar a dieta e a agricultura. / Introduction: Nowadays, Non-Communicable Chronic Diseases (NCCD) are a major challenge in health public. It is evident the role of diet in the control of cholesterol and incidence of cardiovascular disease. In this sense, amaranth arouses great interest due to its hypocholesterolemic property. Studies suggest that amaranth\'s hypocholesterolemic effect is associated with the inhibition of the enzyme HMG-CoA reductase, known as the key process to the endogenous cholesterol synthesis. Objective: Evaluate the hepatic enzymatic activity of HMG-CoA reductase in hamsters fed with amaranth protein. Methodology: Amaranth protein was isolated according to the conventional isoelectric precipitation methodology. Thirty hamsters were divided in 5 groups and were fed diets with different protein source. Experimental groups (I and lcol) had a diet containing 20% of protein amaranth and control groups(C and Cool) received a diet with 20% of casein. Moreover, groups \"col\" had also a diet with 0.1% cholesterol and 13.5% coconut oil in their composition. The lipid metabolism was accompanied through monitoring of plasma concentrations of total cholesterol, triglycerides, HDL and non-HDL fraction in animals. Excretion of cholesterol and bile acids were quantified in the feces of animals and the degree of hepatic steatosis was determined by histological analysis of the liver\'s right lobe. The HMGR enzyme activity in the liver was measured by the CS 1090 Kit from Sigma-Aldrich adjusted in accordance with Cong et al, 2012. The analysis is based on spectrometry with absorbance of 340nm at 37 ° C, which represents the oxidation of NADPH by HMG-CoA reductase in the presence of HMG-CoA substrate. Conclusions: Amaranth protein can be considered as an ally in reducing of injuries generated by dyslipidemia, since it significantly reduced levels of plasma cholesterol and hepatic fat. Furthermore, it was demonstrated its effect on reducing activity of HMG-CoA reductase enzyme in hypercholesterolemic animals, which were fed with amaranth protein. Therefore, once verified the hypocholesterolemic effect of amaranth and its possible action mechanism through HMG-CoA reductase enzyme, stimuli on the production of amaranth are expected as an alternative to diversify the diet and agriculture.
68

Porovnání vybraných kulturních a plevelných druhů z rodu Amaranthus / Comparison choice cultural and weed kinds form stock Amaranthus

VÁLEK, Jan January 2006 (has links)
Amaranthus (L.) belongs to among old cultural crops. Cultural forms of some species were already grown by Aztecs and Incs in ancient times. High nutritive value of seeds redounded to rediscovery of the crops. Tested varieties of cultural amaranth get to the interaction whit wild species of amaranth. This work would had contribute to better knowledge of ecology in the hybrid of cultural variety and weed (A. x turicensis = A. cruentus x A. retroflexus) The aim of this work was to describe production and morphometric characteristics of selected relative cultural and weed species of amaranth (Amaranthus hypochondriacus, Amaranthus cruentus, Amaranthus retroflexus), the hybrid A. x turicensis and to determinate occurrence and survival of weed species A. retroflexus onplaces, where cultural amarant was grown. A. retroflexus shows as a very resistant to damage. Cultural species responded on damage by reduction of majority observed parameters. Cultural species of amaranth responded more on different conditions substrate than the weed species. Response of hybrid on different substratum conditions was in the middle of spectrum of the response in cultural parents and the weed species. Indiference of the hybrid to substrate should be better clear up in the next studies. Weed species is little sensitive to competicion and his characteristics (total biomass, legth inflorescence, height of plants, number of leaves) are different not much. Effect of competition on hybrid shows his non - uniform response probably caused by his considerable variability Absence of cultural amarant and interspecific hybrids shows on relation of these plants to warmer weather that is probably the main factor for their occurrence.
69

Comportamento reologico e termico de sistemas amido de amaranto-caseinato de sodio : efeito da adição de açucar e tempo de acidificação / Rheological and thermal behavior of amaranth starch-sodium caseinate systems : effect of sugar addition and acidification time

Gozzo, Angela Maria 26 February 2008 (has links)
Orientadores: Florencia Cecilia Menegalli, Rosiane Lopes da Cunha / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-10T04:44:46Z (GMT). No. of bitstreams: 1 Gozzo_AngelaMaria_D.pdf: 11741135 bytes, checksum: a214a3f6ddbdeaa7712078b8b0f19f2a (MD5) Previous issue date: 2008 / Resumo: Os amidos são adicionados freqüentemente aos alimentos devido as suas propriedades espessantes e de retenção de água, como estabilizantes coloidais e agentes gelificantes. O amaranto é uma cultura de baixo custo, e seu amido, um novo ingrediente com potencial uso industrial. O caseinato de sódio é um sal derivado da caseína amplamente utilizado como emulsificante em alimentos. O estudo de misturas de proteínas e polissacarídeos é de grande interesse, pois tais combinações podem levar a um intervalo de propriedades mais amplo que os géis puros de proteína ou de polissacarídeo. Neste trabalho, as características físico-químicas do amido e as interações entre amido de amaranto/caseinato de sódio, adicionados ou não de sacarose, foram estudadas em sistemas mantidos a 10 °C e pH no ponto isoelétrico. Estas interações foram estudadas através de análises térmicas (gelatinização e retrogradação), de capacidade de retenção de água, sinerese, análise estrutural e comportamento reológico (em cisalhamento oscilatório e em compressão biaxial) da mistura dos biopolímeros e sacarose, durante e após a gelificação. Foram comparados dois métodos de acidificação, um lento, realizado a 10°C e outro rápido, a 90°C. O caseinato de sódio contribuiu para favorecer a característica elástica e viscosa dos sistemas analisados, principalmente na acidificação lenta, porém, o comportamento reológico foi governado principalmente pela velocidade de acidificação, pois os géis formados pelo processo lento apresentaram G¿ e G¿ superiores aos sistemas formados por acidificação rápida. Géis de caseínato - amido formaram estruturas pouco agrupadas, com cadeias ramificadas, cuja rede ficou mais estruturada com o aumento da concentração dos polímeros, sendo que, a porosidade dos géis formados por acidificação lenta foi maior e mais uniformemente distribuída que dos géis formados por acidificação rápida. A sacarose atuou como um agente anti-retrogradante, sendo que, este efeito foi mais importante para a interação sacarose-amilopectina do que para a sacarose-amilose. Apesar de retardar o envelhecimento, a sacarose não atuou fortemente sobre as interações, sendo que as propriedades dos géis mostraram ser mais fortemente dependentes da concentração de biopolímeros e, principalmente, da temperatura de acidificação. Amostras contendo maiores concentrações de amido/caseinato apresentaram maior capacidade de retenção de água (WHC) e menor sinerese. A retrogradação do amido de amaranto não foi elevada, no entanto, valores de DH (re-gelatinização) aumentaram com a concentração de sacarose e tempo de armazenamento e decresceram com a adição de caseinato de sódio / Abstract: The starches are frequently added to the foods owed their properties and water retention, as colloidal emulsion-estabilizing agents. The amaranth is a low cost culture, and his starch, a new ingredient with potential industrial use. The caseinato of sodium is a salt derived of the casein thoroughly used as emulsion in foods. The study proteins and polysaccharide mixtures is of great interest, because such combinations can take the a wider interval of properties than the pure gels of protein or polysaccharide. In this work, the physiochemical characteristics of the starch and the interactions among amaranthus starch-sodium caseinate, added or not of sucrose, were studied in systems maintained at 10 °C and pH in the isoeletric point. These interactions were studied through thermal analyses, water holding capacity, syneresis, structural analysis and behavior rheologic of the biopolymers-sucrose mixture, during and after the gelation. Two acidification methods were compared, one performed at 10°C (slow) and other, at 90°C (fast). The sodium caseinate contributed to favor the elastic and viscous characteristic of the analyzed systems, mainly in the slow acidification, however, the rheologic behavior was governed mainly by the acidification speed, because the gels formed by the slow process presented G' and G" superiors to the systems formed by the fast acidification. Starch-caseínato gels formed structures low contained, with ramified chains, whose net was more structured with the increase of the polymeric concentration, and, the gels porosity formed by slow acidification was larger and more evenly distributed that of gels formed by fast acidification. The sucrose acted as an anti-retrogradation agent, and, this effect went more important for the sucrose- amylopectin interaction than for the sucroseamylose. In spite of delaying the aging, the sucrose didn't act strongly about the interactions, and the gels properties showed to be more strongly dependent of the biopolymers concentration and, mainly, of the acidification temperature. Samples containing larger starch caseinate concentrations presented larger water holding capacity (WHC) and smaller syneresis. The retrogradation of the amaranth starch was not elevated, however, values of DH increased with the sucrose concentration and time of storage and they decreased with the addition of sodium caseinate / Doutorado / Doutor em Engenharia de Alimentos
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Effect of Aquafeed on Productivity of Red Amaranth and on Water Quality under Aquaponic Cultivation

Medina, Miles D 28 March 2014 (has links)
Aquaponics, the integrated production of fish and hydroponic crops in a recirculating system, is an intensive cultivation method in which metabolic fish wastes fertilize plants. This study compares the effects of two aquafeeds on Red amaranth (Amaranthus tricolor) productivity and on water quality under cultivation of Blue tilapia (Oreochromis aureus), with three aquaponic units (n=3) per treatment over a 60-day trial. The fishmeal-based control feed contains higher crude protein (40%) and phosphorus (1.12%) than the plant-based alternative feed (32% and 0.40%). The alternative feed resulted in a significantly higher amaranth crop yield (p

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