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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.
141

EXTRAÇÃO DE ÓLEO DA POLPA DE ABACATE UTILIZANDO GÁS LIQUEFEITO DE PETRÓLEO PRESSURIZADO E DIÓXIDO DE CARBONO SUPERCRÍTICO COMO SOLVENTES / EXTRACTION OF AVOCADO PULP OIL USING PRESSURIZED LIQUEFIED PETROLEUM GAS AND SUPERCRITICAL CARBON DIOXIDE AS SOLVENTS

Abaide, Ederson Rossi 15 February 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work two differents solvents were used for extraction, carbon dioxide (CO2) in the supercritical state and pressurized liquefied petroleum gas (LPG). The purpose was to extract the oil from the dried avocado pulp comparing these two solvents regarding yield, the time at which the process occurs, adequacy of adjustment of the proposed model to plotted kinetic and the quality of the product obtained by the analysis of their antioxidant activity and gas chromatography analysis coupled with mass spectrometry. Two experimental designs were used, one for each solvent, having as variables the pressure and the temperature with two levels (-1 and +1), and triplicate of the central point (2² + 3 central point), with response the extraction yield of oil. The construction of the kinetic extraction profiles based on the pressure and temperature conditions of experimental design. For the extraction with supercritical CO2 pressure varied in the range of 15 to 25MPa and the temperature ranged from 313 to 353 K, while for extraction with pressurized LPG, pressure and temperature ranged from 0.5 to 2.5 MPa and 293 and 313 K, respectively. It was possible to observe a significant reduction in extraction time using LPG as a solvent, when compared with CO2, and even better extraction yield (57.95%) for LPG and (39.76%) for CO2 in their best extraction conditions experienced. With regard to modeling, it can be seen the appropriateness of the model Sovová the kinetic extraction profiles by means of the adjustment and the kinetic parameters obtained. / Neste trabalho, dois diferentes solventes foram utilizados para a extração, dióxido de carbono (CO2) no estado supercrítico e gás liquefeito de petróleo (GLP) pressurizado. A finalidade do trabalho foi extrair o óleo da polpa de abacate seca, comparando esses dois solventes com relação ao rendimento da extração, o tempo no qual o processo ocorre, a adequação do ajuste do modelo proposto às cinéticas plotadas e à qualidade do óleo obtido, sendo o último avaliado por meio da análise da atividade antioxidante e da análise em cromatografia gasosa acoplada ao espectrômetro de massas. Foram utilizados dois planejamentos experimentais, um para cada solvente, tendo como variáveis a pressão e a temperatura, com dois níveis (-1 e +1) e triplicata do ponto central (2²+3 ponto central), tendo como resposta o rendimento na extração de óleo. A construção dos perfis cinéticos de extração também foi nas condições de pressão e temperatura estabelecidas no planejamento, sendo que para a extração com CO2 supercrítico a pressão variou na faixa de 15 a 25 MPa e a temperatura variou entre 313 a 353 K. Já para a extração com GLP pressurizado, a pressão e temperatura variaram na faixa de 0,5 a 2,5 MPa e 293 e 313 K, respectivamente. Foi possível observar redução significativa no tempo de extração utilizando GLP como solvente quando comparado com CO2, e ainda um melhor rendimento na extração (57,95%) para o GLP e (39,76%) para o CO2 em suas melhores condições de extração testadas. Com relação à modelagem, pode-se observar a adequação do modelo de Sovová aos perfis cinéticos de extração, por meio do ajuste e dos parâmetros cinéticos obtidos.
142

Dovoz mexických avokád do České republiky / Importation of Mexican avocados into the Czech Republic

Dlouhý, Michael January 2015 (has links)
This diploma thesis deals with the import operation of Mexican avocados into the Czech Republic. It is divided into three chapters. The first chapter defines the trade with agricultural crops and depicts its specifics as well as the global avocado market production and export with its key players. A special attention is focused on Mexico, which has primacy in both categories. The second chapter analyzes the avocado market in the Czech Republic, it studies the consumption trends, import history and our key business partners. It also contains a survey that explores the consumption habits of the Czech population. The third chapter is devoted to the actual import operation of organic avocados from Mexico and all its requirements from vendor selection, business documents, logistics and pricing.
143

In Silico Structural Analyses of Avocado WRINKLED Orthologs

Bhatia, Shina 01 May 2019 (has links)
Transcription factor Wrinkled (WRI) 1 is associated with triacylglycerol (TAG) biosynthesis and accumulation in plant tissues. In avocado (Persea americana), a basal angiosperm, four WRI orthologs (1-4) were identified by transcriptome studies and the gene expression of WRI1, 2 and 3 was associated with TAG accumulation in mesocarp tissue. Therefore, it is hypothesized that putative PaWRI1, 2 and 3 but not PaWRI4 are responsible for TAG synthesis in non-seed tissues. To this extent, various in silico analyses were performed to identify similarities and distinct features of putative WRI genes in basal angiosperm relative to maize and Arabidopsis, a monocot and dicot respectively. Predicted structural comparison of these orthologs is expected to reveal the distinct features of avocado WRI paralogs that are associated with the regulation of oil biosynthesis in non-seed tissues.
144

Plan de negocio: Agroexportadora SRA Avocado Export S.A.C.

Ampuero Villafuerte, Silvia, Espinoza Ortiz, Adolfo Edwin, Iparraguirre De La Cruz, Roxana Betzabe 12 October 2020 (has links)
La presente investigación tiene por finalidad elaborar el Plan de Negocios de Agroexportadora de Paltas Hass para el mercado europeo, específicamente de Holanda, y para ello se desarrolla la línea de Negocio de la empresa “SRA Avocado Export S.A” que, mediante la asociatividad con la ONG CEDEP y los agricultores de valles interandinos en Lucanas (Ayacucho) y de la costa en Palpa e Ica (Ica), se lograría ofrecer productos de alta calidad y en volúmenes suficientes. La Justificación e importancia del Plan de Negocios que se propone, se considera viable por 04 razones fundamentales: (i) porque el mercado de la palta de exportación tiene bastante potencial de crecimiento y el Perú viene ocupando los primeros lugares en producción y exportación; (ii) la gran demanda del producto por el descubrimiento de cualidades medicinales y culinarias, tanto nacional como internacional; (iii) experiencia institucional de la ONG CEDEP en manejo del cultivo paltas de exportación y su comercialización que garantizara la calidad del fruto; y (iv) y seguir apoyando a poblaciones rurales en situación de pobreza. Finalmente, los objetivos serán reflejados en el Plan de Negocio, detallando las estrategias, planes y los costos asociados a estos para poder establecer los Estados Financieros del Proyecto de “SRA Avocado”. Conocidas estas cifras, nos permitirá analizar los indicadores de rentabilidad, endeudamiento, liquidez y flujos de efectivo del proyecto. Los factores financieros centrales que acreditan la viabilidad del negocio son el Valor Actual del Proyecto (VAN) que asciende a USD 352,304 y la Tasa Interna de Retorno (TIR) de 55.1%, los cuales nos permiten asegurar que es un proyecto viable financieramente. El plan de negocios servirá como una guía para agricultores e inversionistas, quienes son finalmente los que por medio de un trabajo asociativo lograrían posicionar el producto en el mercado objetivo, y sacar provecho de lo que el producto puede ofrecer al país y a la empresa privada. / The purpose of this research is to prepare the Hass Avocado Agro-exporter Business Plan for the European market, specifically the Netherlands, and for this the business line of the company “SRA Avocado Export SA” is developed which, through association with the NGO CEDEP and the farmers of inter-Andean valleys in Lucanas (Ayacucho) and of the coast in Palpa and Ica (Ica), it would be possible to offer high quality products and in sufficient volumes. The Justification and importance of the proposed Business Plan is considered viable for 04 fundamental reasons: (i) because the avocado market for export has enough growth potential and Peru has been occupying the first places in production and export; (ii) the great demand for the product due to the discovery of medicinal and culinary qualities, both nationally and internationally; (iii) institutional experience of the NGO CEDEP in managing the cultivation of avocados for export and their commercialization that will guarantee the quality of the fruit; and (iv) and continue supporting rural populations living in poverty. Finally, the objectives will be reflected in the Business Plan, they buy the strategies, plans and costs associated with these in order to establish the Financial Statements of the "SRA Avocado" Project. Once these are known, they will analyze the indicators of profitability, indebtedness, liquidity and cash flows of the project. The central financial factors that prove the viability of the business are the Present Value of the Project (NPV) which amounts to USD 352,304 and the Internal Rate of Return (IRR) of 55.1%, which allow us to ensure that it is a financially viable project. The business plan will serve as a guide for farmers and investors, who are ultimately the ones who, through associative work, would be able to position the product in the target market, and take advantage of what the product can offer the country and the private company. / Trabajo de investigación
145

Effects of irrigation, 1-methylcyclopropene (1-MCP) and cold storage temperature on quality of 'hass' avocado fruit

Mamila, Isaac Mareme January 2020 (has links)
Thesis (M.Sc. (Horticulture)) -- University of Limpopo, 2020 / The South African Agricultural Sector has a mandate to reduce water use so that water can be available for other economic sectors. Thus, various water saving techniques must be continuously investigated in agricultural production to find efficient water use technique that saves water without compromising fresh fruit quality. Therefore, combined effect of irrigation method, 1-methylcyclopropene (1-MCP) and cold storage temperature on postharvest quality of ‘Hass’ avocado fruit was evaluated. Postharvest attributes of fruit colour, flesh firmness, ripening percentage, respiration, weight loss, body rot, stem end-rot, vascular browning, chilling injury and electrolyte leakage were assessed for 2 x irrigation methods [Full irrigation (FI) and Partial root-zone drying (PRD)], 2 x 1-methylcyclopropene (300 ng/L 1-MCP and untreated) and 2 x storage temperature (2.0 and 5.5°C) treatments. An interaction between the three treatments did not significantly (P > 0.05) influence fruit colour, flesh firmness, ripening percentage, fruit weight loss, body rot, stem end-rot, vascular browning, chilling injury and electrolyte leakage. Their combined effect was only significant (P = 0.019) on ‘Hass’ fruit respiration rate. The combination of full and PRD irrigation, 1-MCP and low storage temperature (2.0°C) did not negatively affect fruit quality. However, fruit stored at 2.0°C without 1-MCP treatment were affected by chilling injury when compared with fruit stored at 5.5°C. In conclusion, due to the inconclusiveness of results obtained, further studies, on the effect of these treatments especially under 5.5°C storage temperature should be carried out prior recommending the combination treatment for export markets. / Agricultural Research Council-Tropical and Subtropical Crops (ARC-TSC) and Agricultural Sector Education Training Authority (AgriSeta)
146

Efficacy of water soluble silicon for control of phytophthora cinnamomi root rot of avocado

Bekker, Theo Frederik 17 September 2007 (has links)
In the current study potassium silicate (20.7% SiO2) induced a 100% inhibition of P. cinnamomi mycelial growth at all concentrations tested. Total inhibition for all fungi tested (Alternaria solani, Colletotrichum gloeosporioides, Curvularia lunata, Drechslera sp., Fusarium oxysporum, Fusarium solani, Glomerella cingulata, Lasiodiplodia theobromae, Mucor pusillus, Natrassia sp., Pestalotiopsis maculans, Phomopsis perniciosa, Phytophthora capsicii, Phytophthora cinnamomi, Pythium F-group, Sclerotinia sclerotiorum, Sclerotium rolfsii, Stemphylium herbarum and Verticillium tricorpus) was attained at a concentration of 40ml.l-1 and higher. Although the high pH of potassium silicate solutions does contribute to the inhibition of fungal growth, the inhibitory effect of potassium silicate on fungal growth in vitro is mostly fungicidal rather than attributed to a pH effect. Phytophthora root rot of avocado nursery trees can be inhibited successfully by potassium silicate application. The effectiveness of potassium silicate application depends however on the repetition of applications. These findings are of paramount importance as this implies that potassium silicate may be a alternative control measure to inhibit the effects of P. cinnamomi on avocado nursery trees. Silicon either stimulates plant growth or imparts some form of protection to avocado roots if applied prior to P. cinnamomi inoculation. Potassium silicate applied as a soil drench resulted in higher root densities compared to that of potassium phosphonate (Avoguard®) injections and untreated control trees. Reapplication again resulted in the best disease suppression and stimulation of new root growth. These results correlated well with tree canopy ratings, as trees that received silicon frequently, showed better canopy conditions compared to the untreated control treatments. Potassium silicate application leads to effective inhibition of Phytophthora cinnamomi infection in avocado orchards. Potassium silicate application resulted in an increase of crude phenols and phenolic polymers in avocado roots cells to similar levels to that obtained in roots from potassium phosphonate (Avoguard®) treated trees. Potassium silicate application leads to lower cell wall bound phenolics. The results of the current study support the hypothesis that silicon application, through an elevation of the total phenolic levels, causes an increase of resistance against P. cinnamomi root rot in avocados. AFRIKAANS : Kaliumsilikaat (20.7% SiO2) induseer ‘n 100% inhibisie van P. cinnamomi groei by alle getoetste konsentrasies. Totale inhibisie van alle swamme getoets (Alternaria solani, Colletotrichum gloeosporioides, Curvularia lunata, Drechslera sp., Fusarium oxysporum, Fusarium solani, Glomerella cingulata, Lasiodiplodia theobromae, Mucor pusillus, Natrassia sp., Pestalotiopsis maculans, Phomopsis perniciosa, Phytophthora capsicii, Phytophthora cinnamomi, Pythium F-groep, Sclerotinia sclerotiorum, Sclerotium rolfsii, Stemphylium herbarum en Verticillium tricorpus) was verkry by ‘n konsentrasie van 40ml.l-1 en hoër. Alhoewel die hoë pH van kaliumsilikaat wel ‘n inhiberende uitwerking het op swamgroei, is die suksesvolle inhibisie van swamgroei grootliks toe te skryf aan die swamwerende effek van kaliumsilikaat op swamgroei in vitro eerder as ‘n pH effek. Phytophthora wortelvrot van avokado kwekelinge kan suksesvol onderdruk word met kaliumsilikaat toediening. Die effektiwiteit van die toediening hang wel af van die hertoediening daarvan. Hierdie bevindinge is van kardinale belang aangesien dit impliseer dat kalium silikaat ‘n alternatiewe beheer middel is om Phytophthora wortelvrot te inhibeer in avokado kwekelinge. Of silikon stimuleer plant groei, of dit induseer ‘n vorm van beskerming in avokado wortels voor infeksie plaasvind. Kaliumsilikaat toediening as ‘n grond-benatter lei tot hoër worteldigthede in vergelyking met kaliumfosfaat (Avoguard®) staminspuitings en onbehandelde kontrole bome. Hertoediening lewer die beste resultate, maar drie toedienings per seisoen is voldoende. Worteldigdheid verhoging na silikaat toedienings korreleer goed met blaredak gesondheid, aangesien bome wat gereeld behandel is met silikon beter blaredekking getoon het in vergelyking met die kontrole bome. Kaliumsilikaat toediening lei to effektiewe inhibisie van Phytophthora cinnamomi infeksie in avokado boorde. Kaliumsilikaat toediening lei tot ‘n toename in totale fenole en fenoliese polimere in avokado wortel selle tot soortgelyke vlakke soos gevind in avokado weefsel vanaf kaliumfosfaat behandelde bome. terselfdertyd lei silikaat toediening tot laer selwand gebinde fenole. Hierdie resultate ondersteun die hipotese dat kaliumsilikaat toediening, deur die verhoging van oplosbare fenole in avokado wortelselle, die plant se weerstand verhoog, en die effek wat Phytophthora wortelvrot het op avokado plante inhibeer. Copyright / Dissertation (MSc (Agric) Horticulture)--University of Pretoria, 2011. / Plant Production and Soil Science / unrestricted
147

La estrategia de internacionalización: análisis de las dimensiones del modelo Uppsala empleadas por las empresas agro exportadoras de palta Hass ubicadas en la región Ica hacia el mercado de Estados Unidos durante el periodo 2014-2018

Vega Samamé, Bianca Camila, Teque Villajuan, Mariell Cristhina 15 August 2020 (has links)
El objetivo de la presente investigación es analizar cada una de las 4 dimensiones del modelo Uppsala, “reconocimiento de oportunidades”, “posición de la red de contactos”, “aprendizaje, creación y construcción de la confianza” y “decisiones de relación de compromiso”, las cuales son empleadas por las agro exportadoras hacia Estados Unidos de palta Hass en Ica. Hallando así, diferentes variables dentro de estas dimensiones que se emplean para lograr la internacionalización del agro exportador iqueño. El enfoque de la investigación es mixto, se comenzó con un análisis cualitativo donde se usó como herramienta la entrevista a profundidad, realizada a 6 expertos para poder validar las variables más destacadas dentro las 4 dimensiones establecidas en Uppsala. Luego se realizó el análisis cuantitativo, en donde la herramienta que se empleó fue una encuesta aplicada a las 10 empresas agro exportadoras de palta Hass iqueñas pertenecientes a la población total de la investigación. Analizamos los resultados aplicando el modelo de análisis factorial, el cual nos ayudó a hallar perfiles de las agro exportadoras por cada dimensión. Los resultados obtenidos concluyen que las dimensiones “reconocimiento de oportunidades” y “aprendizaje, creación y construcción de la confianza” del modelo Uppsala son las más influyentes en la internacionalización de la palta Hass de agro exportadoras iqueñas. Asimismo, se concluyó que los factores “estudio de mercado en el país de destino”, “clientes fidelizados”, “empaque perfecto”, “tener mayores ganancias” fueron los que impactaron más en la decisión de estas agro exportadoras para internacionalizar la palta Hass hacia un mercado tan competitivo como es Estados Unidos. / The objective of this research is to analyze each of the 4 dimensions of the Uppsala model, "recognition of opportunities", "position of the network of contacts", "learning, creation and construction of trust" and "decisions of commitment relationship ", Which are used by agricultural exporters to the United States of Hass avocado in Ica. Thus, finding different variables within these dimensions that are used to achieve the internationalization of Ica's agricultural exporter. The research approach is mixed, it began with a qualitative analysis where the in-depth interview was used as a tool, carried out with 6 experts to be able to validate the most outstanding variables within the 4 dimensions established in Uppsala. Then the quantitative analysis was carried out, where the tool that was used was a survey applied to the 10 agro-exporting companies of Hass avocado belonging to the total population of the investigation. We analyzed the results by applying the factor analysis model, which helped us find profiles of agricultural exporters for each dimension. The results obtained conclude that the dimensions "recognition of opportunities" and "learning, creation and construction of trust" of the Uppsala model are the most influential in the internationalization of the Hass avocado from agro-exporters from Ica. Likewise, it was concluded that the factors "market study in the destination country", "loyal customers", "perfect packaging", "having higher profits" were the ones that had the greatest impact on the decision of these agro-exporters to internationalize Hass avocado towards a market as competitive as the United States. / Tesis
148

Soil Carbon as A Soil Quality Indicator of A Fruit Orchard In Puerto Rico

Cordero-Irizarry, Patricia Marie 07 October 2021 (has links)
No description available.
149

The use of cover crops to increase yield and reduce pest pressure in a commercial avocado orchard at Levubu, Limpopo Province

Nengovhela, Ndoweni Mary 13 August 2020 (has links)
MENVSC / Department of Ecology and Resource Management / The study investigated the impact of cover crops (Medicago sativa, Lotus corniculatus, Trifolium pratense, Melilotus alba and Phacelia tanacetifolia), bare soil and natural ground cover on pest and beneficial arthropods, soil health, crop yield, pest damage and weed suppression in avocado orchards. The trial plots were sited within established commercial avocado orchards with trees of similar cultivar (‘Hass’), soil-type and age, located in Levubu, Limpopo, South Africa. Mixtures of cover crops were planted in the alleys of avocado orchards and the effects were compared to that of a control (other half of the orchard). Mechanical clearing of vegetation in half of the alleys of different avocado orchards were compared to the other half that was left undisturbed. Data were collected during the flowering and fruit set stages of the avocado trees in the months of September - November 2019. Results revealed that there was higher abundance and diversity of flowering plants in the orchard alleys of the cover crop treatment compared to the control comprising of natural vegetation. Cover crops had a significantly positive effect on the soil health of the orchard but little or no effect on beneficial arthropods within the orchard nor any positive effect on the pests of avocados. However, the number of thrips scouted on the fruit were significantly less where cover crops were established. Avocado scale infection rates were also significantly lower where cover crops were established. There were significantly less arthropods, and specifically pests, pollinators and herbivores where the topsoil was removed mechanically. The yield resulting from the orchard half where cover crops were established were significantly higher. More research still needs to be done about the use, management and impact of cover cropping on not only commercial avocado orchards but on other fruit crops. This study shows good evidence for the benefits for using cover crops and the negative effects in having no vegetation cover in the orchards. / NRF
150

Factores determinantes en las exportaciones peruanas de palta Hass a Estados Unidos en los periodos 2010-2011 y 2013-2014 en el marco Perú-Estados unidos

Meza Marquez, Ana Stefanny, Osorio Ayala, Mercedes Graciela 02 1900 (has links)
La presente investigación analiza los factores determinantes que influyeron en las exportaciones peruanas de Palta Hass a Estados Unidos en los periodos 2010-2011 y 2013-2014, los cuales representan la mayor variación porcentual entre los años 2010 al 2017. Las exportaciones de palta hass peruana a Estados Unidos aumentaron de USD $316 miles en el 2010 a USD 30,174 miles en el 2011, con una variación de 9,499%. Seguido del periodo 2013-2014, donde las exportaciones aumentaron de USD 50,700 miles en el 2013 a USD 160,470 miles en el 2014, con un crecimiento porcentual de 228%. Al analizar estos dos momentos, se desea encontrar los factores determinantes que lograron este impacto en las exportaciones de palta hass y puedan ser retomadas o replicables a futuro. Como parte de la investigación, se realizaron entrevistas a los actores involucrados como entidades de El Estado, Académicos, ProHass y empresas exportadoras peruanas de palta hass a Estados Unidos durante ambos periodos. La información analizada indica que durante el primer periodo 2010-2011, existe una mayor relevancia de factores internos sobresaliendo el factor eliminación del tratamiento de frío. A diferencia del segundo periodo, donde los factores externos poseen más relevancia, resaltando el factor baja en la producción de la competencia, México y California. / The present investigation analyzes the determining factors that influenced the Peruvian exports of Palta Hass to the United States in the periods 2010-2011 and 2013-2014, which represent the highest percentage variation between 2010 and 2017. Peruvian avocado exports have The United States increased from USD $ 316 thousand in 2010 to USD 30,174 thousand in 2011, with a variation of 9.499%. Followed by the period 2013-2014, where exports increased from USD 50,700 thousand in 2013 to USD 160,470 thousand in 2014, with a percentage growth of 228%. When analyzing these two moments, we want to find the determining factors that have achieved this impact in avocado hass exports and can be resumed or replicated in the future. As part of the investigation, interviews were conducted with the actors involved such as the State, Academicians, ProHass and Peruvian companies exporting avocados to the United States during both periods. The analyzed information indicates that during the first period 2010-2011, there is a greater relevance of internal factors, excelling the factor of elimination of cold treatment as an outstanding factor. Unlike the second period, where external factors have more relevance, highlighting the factor of low in the production of the competition, Mexico and California. / Tesis

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