No description available.

No description available.

Compared to natural forests, fast-growing plantations of exotic species such as Pinus radiata are often perceived as marginal habitat or unsuitable habitat for most native species. By studying Coleoptera (beetles) in a variety of landscape elements (pasture, native forest and different aged Pinus radiata stands) in a highly modified and fragmented landscape in New Zealand I aimed to determine the value of exotic plantation forests for native biodiversity, and how these species are affected by different sized clearfell harvest areas. Pitfall trap sampling of beetles showed that plantation forest stands can provide suitable complimentary habitat to native forest for many species. Rarefied species richness of Carabidae, Scarabaeidae and Scolytinae was not significantly different between habitats, however, habitat types differed significantly in their beetle community composition. Comparing different production habitats, Pinus radiata stands had a beetle community composition most similar to native forest. However, a small minority of species, e.g., Dichrochile maura, were restricted to native forest habitat highlighting the importance of retaining indigenous ecosystems within plantations. Unlike human modified habitats, native forests did not provide suitable habitat for exotic species. Clearfell harvesting is controversial and its impact on biodiversity is a key constraint for many forest certification programs, such as that administered by the Forest Stewardship Council (FSC). Despite this, no replicated manipulative experimental studies of the impact of different sized clearfell harvest areas on biodiversity have been undertaken at scales relevant to the New Zealand forest industry. One potential model of the impact of different clearfell harvest sizes is the concept of a threshold size. A threshold scenario may occur where clearfell harvest impacts increase at a rate disproportionate to the change in clearfell size over a small range of harvest areas, but impacts remain relatively unchanged either side of the threshold zone. I sampled Coleoptera in experimentally created 0.01, 0.05, 0.5, 5.0, 50 and 500 ha clearfells within Pinus radiata plantations in the central North Island of New Zealand. The wide range of clearfell harvest sizes, including some very small areas, such as 0.01 ha was instigated in an attempt to document potential clearfell harvest size thresholds. Rarefied native beetle species richness was higher in harvest areas compared to adjacent mature plantation stands. The beetle species richness in 5 ha and 500 ha harvest areas was significantly greater species than that in small 0.01 - 0.5 ha harvest areas. Although, the high beetle diversity recorded in 500 ha clearfells should be treated with caution due to confounding spatial autocorrelation. The degree of change in beetle community composition increased with increasing clearfell harvest area. Beetle assemblages in large harvest areas were less similar to their paired adjacent mature forest than smaller harvest areas. Although, constrained multivariate ordination techniques did show a short-term change in beetle species composition between recently clearfelled harvest areas of as little as 0.05 ha and adjacent mature P. radiata stands. The colonisation by open-habitat disturbance-adapted species was a key driver of this change, some species dispersed into clearfelled stands in significant densities within days post-harvest. Overall, there were no distinct short-term trends to the change in species richness as a function of increasing harvest area that would suggest an ecological impact threshold response. If short-term outcomes of clearfell harvesting are ameliorated by successful recolonisation, the long-term spatial arrangement of different aged stands becomes more important for the maintenance of biodiversity at the landscape level than short-term consequences of harvesting. By sampling selected beetle taxa in 1, 2, 4, 8, 16 and 26 year-old stands, I found that the abundance of seven out of eight of the species selected for analysis recovered to levels similar to those in adjacent mature forest within the timeframe of a single harvest rotation. Individual species utilised different aged stands, indicating different life-history strategies. For example, open-habitat, disturbance-adapted species such as Cicindela tuberculata and Sitona discoideus were prominent in young stands, and forest species such as Pycnomerus sophorae and Paracatops phyllobius were highly abundant in older stands. These alternative life-history strategies highlight the benefits of maintaining a mixture of different aged stands to increase biodiversity at the landscape level. This thesis fills an important gap in our knowledge of biodiversity in production landscapes. I show that plantation forests have value as complimentary habitat to native forest and they make an important contribution to the maintenance of biodiversity at the landscape level. Although clearfell harvesting is a severe disturbance to the forest ecosystem, the long-term recovery of beetle populations suggests that harvesting is not the key limiting factor to the enhancement of biodiversity in the plantation forests studied. This unusual situation is possibly the result of prior land-use history, as many plantations were established on degraded pastoral land, and harvest-sensitive species are unlikely to have survived this initial land-use change. As such, the severity of the long-term impacts of clearfell harvesting on biodiversity are likely to be context specific and will vary accordingly. The importance of spatial heterogeneity of habitat elements, including different aged plantation stands and native forest remnants, needs to be investigated in more detail to determine what limits biodiversity in this plantation landscape. Key points to consider are the proximity to, and proportion of, native forest cover in the landscape and the degree of connectivity among native remnants. It is these landscape-level attributes that may determine biodiversity at a regional scale, and more emphasis should be placed on landscape scale factors and there interaction with stand specific forest management practices. For example, the spatial mosaic of harvesting areas may need to be of a finer-scale when there are fewer native remnants within the landscape.

A escolha do espaçamento de plantio tem como objetivo inicial proporcionar para cada árvore o espaço suficiente para se obter o crescimento máximo com melhor qualidade e menor custo. Do ponto de vista da colheita mecanizada, o aumento da densidade da floresta implica diretamente na redução do volume individual das árvores, ocasionando também uma redução da capacidade produtiva do harvester.O objetivo deste estudo foi avaliar o efeito de diferentes espaçamentos e arranjos do plantio de povoamentos de eucalipto sobre a capacidade e custo operacional da colheita com harvester. A coleta de dados de produtividade do harvester foi feita em condições reais de operação, em dois povoamentos de eucalipto com diferentes espaçamentos: 6,0; 7,5; 9,0; 12; e 18 m2 por árvore, além do uso de um simulador de colheita. Usando-se os valores das variáveis espaçamento (E), volume médio (VM), diâmetro à altura do peito (DAP) e altura (H) aplicou-se um teste de regressão stepwise e se fez uma correlação para medir a participação dessas variáveis na capacidade operacional. Os custos operacionais dos equipamentos foram determinados através de um método contábil proposto pela FAO. O volume médio (VM) por árvore explicou 88 % da capacidade operacional da colhedora florestal e o espaçamento (E) afetou 8,5 %, sendo que o maior espaçamento é a causa do maior volume individual. Conseqüentemente, o custo da operação de colheita de árvores com harvester foi menor naqueles tratamentos com maior espaçamento. Os tratamentos simulados podem ser utilizados como reais para este tipo de comparação, dado que os tratamentos usando o simulador seguem a mesma tendência que a colheita real, ou seja, a maior espaçamento, maior volume individual por árvore e por tanto maior capacidade operacional do harvester. A maior proporção de tempo médio do ciclo de colheita por árvore foi o tempo de traçamento em condições de trabalho real, sendo que no caso da simulação da colhedora o maior tempo do ciclo foi de descasque-desgalhe. O modelo empírico apresentado pode ser uma ferramenta válida para predição de capacidade operacional do harvester. / Plantation spacing selection has the primary object of assigning each tree enough space in which maximum growth and best quality can be attained with a minimum cost. From the harvest standpoint, an increase in stand density directly implies a decrease of individual tree volume, reducing also harvester productive capacity. The objective of this research is to assess the effects of several initial spacing and arrangement in eucalypt plantations on production capacity and operational capacity and costs of forest harvester. Real operational data were collected from two eucalypt plantations at different initial spacing, viz. 6.0, 7.5, 9.0, 12 and 18 m2 per tree. Simulation data were obtained from forest harvester simulator. Using spacement (E), mean tree volume (MV), diameter at breast height (DBH) and height (H) values, a stepwise regression test procedure was run, and correlations computed in order to measure their participation in operational capacity. Operational costs were computed with accounting method proposed by FAO. Mean tree volume (MV) explained 88% of forest harvester operational capacity. Spacement (E) affected 8.5% of harvester operational capacity; wider spacements were related to higher individual tree volumes. Harvesting operation costs were lower in wider spaced treatments. Simulated treatments can be used as in field conditions. Treatments under simulated conditions and real conditions had the same results: the wider the spacement, more individual volume tree and higher harvester operational capacity. The higher time of the harvest cycle was the cross-cutting operation in real conditions and the debarked and delimbing in simulated conditions. The empirical model can be a valid tool to predict the harvester operational capacity

Made available in DSpace on 2014-06-11T19:28:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-01-30Bitstream added on 2014-06-13T20:18:27Z : No. of bitstreams: 1 rossi_cvs_me_botfca.pdf: 1120558 bytes, checksum: 3edb3706a438d8f524e6adbaabfbe9e6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O herbicida metribuzin é recomendado para o controle de plantas daninhas na cultura de cana-de-açúcar. Em áreas de cana-de-açúcar sem queima colhida mecanicamente, o comportamento do herbicida na palha deixada sobre o solo não é muito conhecido. Quando um herbicida é aplicado diretamente sobre a palha, uma parte pode ficar retida e outra poderá atingir o solo, dependendo da quantidade e qualidade da palha, período e intensidade de chuvas após aplicação. Para melhor entender esse comportamento, avaliou-se neste trabalho a dinâmica do metribuzin aplicado sobre a palha de cana-de-açúcar cv. SP 80-1816 em diferentes períodos e intensidades de chuvas após a aplicação. Avaliou-se também, a eficiência do metribuzin associado à presença da palha sobre as plantas daninhas Euphorbia heterophylla, Ipomoea grandifolia, Brachiaria plantaginea e Sida rhombifolia. Foram conduzidos três experimentos para entender-se a dinâmica do metribuzin em delineamento experimental inteiramente casualizado, com quatro repetições, sendo que no primeiro avaliou-se a transposição no momento da aplicação sobre 0; 1; 2,5; 5; 7,5; 10; 15; 20 t.ha-1 de palha. No segundo avaliou-se a passagem do herbicida em 5; 10; 15; 20 t.ha-1 de palha, simulando-se o equivalente a 2,5; 5,0; 10; 15; 20; 35; 50 e 100 mm de chuva, um dia após a aplicação (DAA) e simulação de 20 mm aos 7 e 14 DAA. No terceiro, o efeito de diferentes períodos de permanência (0; 1; 7; 14 e 28 DAA) do metribuzin na palha (10 t.ha-1) em função das mesmas precipitações simuladas no segundo estudo. A quantificação do herbicida foi realizada por cromatografia líquida de alta eficiência (CLAE). Para o estudo de eficiência do metribuzin associado à presença da palha, sobre as plantas daninhas, foi conduzido um experimento, com vasos, em casa de vegetação. O delineamento experimental foi inteiramente... / The herbicide metribuzin is recommended for weed control of sugar cane crops, but up to now, the behavior of this herbicide on the straw left on the soil surface of sugar cane areas harvested mechanically with burning is not very known. When an herbicide is applied directly on the straw, part of it is retained and part may reach the soil, depending on the amount of straw, intensity of rainfalls and time interval after application. In order to understand the metribuzin behavior, this work evaluated the dynamics of metribuzin in sugar cane straw cv. SP 80-1816 in different time intervals and different intensity of rainfalls after its application, besides the metribuzin efficacy associated to the presence of the straw over the weeds Euphorbia heterophylla, Ipomoea grandifolia, Brachiaria plantaginea and Sida rhombifolia. Three studies were carried out for the study of the metribuzin dynamics, by using a completely randomized design with four replications. The first experiment evaluated the herbicide transposition in 0; 1.0; 2.5; 5.0; 7.5; 10; 15; 20 t.ha-1 of straw at the moment of application; the second evaluated the herbicide transposition in 5; 10; 15; 20 t.ha-1 of straw, but with rainfall equivalent to 2.5; 5.0; 10; 15; 20; 35; 50 and 100 mm being simulated one day after the metribuzin application (DAA), and 20 mm of rainfall at 7 and 14 DAA. The third experiment evaluated the effect of different permanence periods of metribuzin (0; 1; 7; 14 and 28 DAA) on the straw (10 t.ha-1) in function of the same simulated precipitations as in the second study. In all these studies, the quantification of the herbicide was accomplished by HPLC. For the study on the metribuzin efficacy associated to the presence of straw on the weeds, an experiment was carried out in pots maintained in greenhouse, using the completely randomized... (Complete abstract, click electronic access below)

Resumo: O objetivo deste trabalho foi avaliar a influência dos sistemas de adubação (na pré-semeadura e na semeadura) e dos consórcios de culturas intercalares (milho + feijão-mucuna-cinza-anã, milho + feijão-guandu-anão e milho + feijão-lab-lab) na cultura do milho no primeiro ano; e no segundo ano avaliar a influência dos sistemas de adubação (na pré-semeadura e na semeadura) e dos manejos de resíduos (rolo-faca, roçadora e triturador de palhas) na cultura da soja. O experimento foi realizado na FCAV- UNESP utilizando-se o delineamento em blocos ao acaso no esquema fatorial (2 x 3) com quatro repetições nos dois anos agrícolas. Os componentes avaliados foram na máquina, no solo e na planta. O diâmetro do colmo, a altura de inserção da primeira espiga e a altura de plantas de milho resultaram em maiores valores para o sistema de adubação na semeadura. O número de fileiras, espigas viáveis, índice de espiga, estande final, biomassa seca no solo, produtividade, fluxo de palha, fluxo de sabugo, fluxo de grãos e as perdas na colheita não foram afetados pelos sistemas de adubação e pelos consórcios, na cultura do milho. A avaliação da distribuição longitudinal de plantas de soja na semeadura, e o fluxo de material de soja na colhedora não foram afetados pelos sistemas de adubação e pelos manejos dos resíduos. As plantas de soja obtiveram maior altura de inserção da primeira vagem e número de vagens no manejo com rolo-faca. A produtividade da soja não foi afetada. / Abstract: The aim of the present study was to evaluate the influence of the fertilization systems (at pre-sowing and sowing) and those consorts of intercalated crops (corn + bean-Stizolobium deeringianum, corn + bean-Cajanus cajan and corn + bean-Dolichos lab lab) in corn crop during the first year; and to evaluate, in the second year, the influence of the fertilization systems (at pre-sowing and sowing) and the management of chaff (knife roller, rotary mower and straw crusher) in the soybean crop. The experiment was done at FCAV-UNESP with totally randomized delineation, on factorial scheme (2x3) with four repetitions during the two agricultural years. The components evaluated were: machine, soil and plant. The stalk diameter, the insertion height of the first cob and the height of corn plants presented higher values for the fertilization system at sowing. The number of rows, viable cobs, cob rate, final stand, dry mass on soil, productiveness, flow of straw, cob and grains and the losses in the harvest were not affected by the fertilization systems and by the consorts in the corn crop. The evaluation of longitudinal distribution of soy plants at sowing and the soybean material flow in the harvester were not affected by the fertilization systems and by the management of chaff. The soybean plants presented higher height of insertion of the first string bean and the number of string beans in the knife roller management. The soybean yield was not affected. / Orientador: Carlos Eduardo Angeli Furlani / Coorientador: Rouverson Pereira da Silva / Banca: Afonso Lopes / Banca: José Eduardo Corá / Banca: Alberto Carvalho Filho / Banca: Antonio Machado de Rezende / Doutor

Orientador: Maria Aparecida Anselmo Tarsitano / Banca: Élcio Hiroyoshi Yano / Banca: Maura Seiko Tsutsui Esperancini / Resumo: O presente trabalho teve como objetivo realizar um estudo que quantificasse o impacto gerado pelo transporte da palha para a indústria no dimensionamento da frota, no valor dos investimentos iniciais para aquisição dos equipamentos do corte, carregamento e transporte (CCT) mecanizados da cana-de-açúcar picada sem queima e na viabilidade econômica dessas operações. Os estudos foram conduzidos em parceria com uma empresa do setor sucroalcooleiro localizada na região Oeste do Estado de São Paulo, durante os anos de 2007 e 2008. A metodologia proposta foi composta pelo acompanhamento das atividades rotineiras da empresa, visando à obtenção de dados reais de campo. Os equipamentos utilizados nas operações foram divididos em sistemas: corte mecânico, carregamento, transporte e apoio. Se for opção da empresa a colheita integral da cana-de-açúcar sem a separação da palha do colmo no campo, os equipamentos industriais deverão ser adequados para a realização da separação da palha do colmo a seco. Ao se simular os dois tipos de colheita mecanizada (com e sem palha) se obtêm duas configurações diferentes para a quantidade de ART perdido com acréscimo de palha na moagem, assim como quantidades diferentes de geração de energia para venda. Para a análise de viabilidade econômica dos dois sistemas estudados, foi estruturado um fluxo de caixa, onde é possível verificar os valores das entradas e saídas dos recursos e produtos. Os resultados mostram que a presença da palha interfere no dimensionamento dos equipamentos envolvidos do CCT, fazendo assim, com que os investimentos sejam diferentes. O custo operacional total (COT) em R$/hectare também foi mais oneroso no sistema em que não se separa a palha dos colmos devido à redução na capacidade de campo. O aumento do potencial de exportação de energia elétrica, devido à presença da palha na indústria, faz com que ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study had the goal to quantify the impact generated by the transport of straw to factory in the fleet sizing, value of initial investments for equipment purchase involved in cut, loading and transportation (CCT) mechanized of chopped sugarcane without burning and in the economic viability of these operations. The studies were conducted in partnership with a company located in Western part of São Paulo State, during the years 2007 and 2008. The proposed methodology was composed of monitoring the daily activities of this company, aiming at collecting real field data. The equipment used in operations were divided into systems: mechanical cutting, loading, transportation and support. If the company chose the sugarcane harvesting without separating the straw in the field, the industrial equipment expected to change. By simulating the two types of mechanical harvesting (with and without straw) gets two different settings for the amount of lost ART with straw increase in the crushing, as well different amounts of power generation for sale. For the analysis of economic feasibility of the two systems studied, was structured cash flow, where it‟s possible checking the values of inputs and outputs of resources and products. The results showed that the presence of straw interferes in the equipment sizing involved in the CCT, making the investments different. The total operational cost (COT) in R$/hectare was also more expensive in the system that does not separate the straw due to the reduction in the field capacity. The increase in the export potential of electricity, due to the presence of straw in the factory, makes this system feasible, thus covering the difference found between the investment and the operational costs / Mestre

L'objet de l'étude menée vise la récupération de micro-énergie renouvelable au moyen des matériaux piézoélectriques, pyroélectriques et thermoélectriques. Cette étude porte sur l'optimisation de trois aspects de la récupération de micro-énergie : (i) le couplage entre le générateur et l'environnement, (ii) l'efficacité de conversion d'énergie par le choix adéquat de matériaux et (iii) l'extraction de l'énergie électrique. Des études expérimentales et théoriques ont été menées en premier lieu dans des conditions de laboratoire pour une meilleure compréhension des phénomènes de récupération de micro-énergie, puis dans des conditions réelles pour vérifier les performances effectives des dispositifs réalisés. Concernant l'effet thermoélectrique, une nouvelle méthode de récupération de micro-énergie ambiante et solaire est présentée. Cette méthode utilise les générateurs thermoélectriques et les effets des chaleurs sensibles et latentes des matériaux à changement de phase pour produire des micro-énergies aussi bien de jour que de nuit. Une puissance maximale de 1Wm-2 avec un matériau thermoélectrique (Bi2Te3) a été obtenue. Concernant l'effet pyroélectrique, l'effet des variations des vitesses du vent au cours du temps est exploité. Une variation temporelle maximale de la température de 16°C/mn est disponible, ce qui a conduit à une puissance moyenne récupérée de 0.6mWm-2. Concernant l'effet piézo-électrique, une structure mécanique de type harmonica a été développée ainsi qu'une estimation des efforts d'interaction fluide-structure. Le prototype développé fonctionne à partir des vitesses du vent de 2ms-1 et génère une production d'énergie électrique de 8.9mWm-2. A titre d'illustration, une application typique a été présenté (refroidissement de panneau photovoltaïque). Elle montre une augmentation de la production d'électricité autour de 10%. L'application met en évidence l'utilisation des micro-énergies renouvelables au service de la production de macro-énergie. / The aim of this study is to investigate ambient energy harvesting with coupling effect of piezoelectric, pyroelectric and thermoelectric materials. Three basic problems lie in an energy harvesting process with these coupling effects: (i) design and optimize a structure which is able to accumulate the micro-power from the energy source and transform it into the favorable loading on the active material, (ii) improve the energy conversion efficiency according to the suitable choice of material properties and (iii) develop an energy harvesting circuit which is able to improve the energy conversion efficiency. The developed approach was experimental and numerical studies at first in laboratory conditions for deep understanding of energy harvesting process and then in outside conditions for verifying actual performance of the realized devices. On the thermoelectric coupling effect, a new method of harvesting solar and ambient energy is presented. The method is based on thermoelectric and both sensitive and latent heat effects for energy harvesting day and night. A maximum power generation of 1Wm-2 is achieved with thermoelectric material (Bi2Te3). On the pyroelectric effect, the inherent fluctuation with time of the natural wind speed was used. A maximum time variation of temperature of 16°C/minute was achieved which corresponds to an average power of 0.6mWm-2. On the piezoelectric effect, a mechanical structure which is enlightened from harmonica was developed and dynamic fluid-structure problems were addressed. The developed prototype begins to work for wind speed around 2ms-1 and a maximum power generation of 8.9mWm-2 was achieved. Ultimately, a typical building application (automatic control of water cooling photovoltaic panel) with the harvested solar thermal energy is introduced. The proposed application highlights an example of using harvested micro-energy to improve macro-energy production (around 10%).

Submitted by ISABELA NOGUEIRA FONSECA CORDEIRO (isabela.cordeiro@ifma.edu.br) on 2018-09-04T04:17:31Z No. of bitstreams: 1 Dissertação definitiva, Isabela.pdf: 2210228 bytes, checksum: c54245ee348cebaa75204af69c942d9d (MD5) / Approved for entry into archive by Neli Silvia Pereira null (nelisps@fcav.unesp.br) on 2018-09-04T13:04:44Z (GMT) No. of bitstreams: 1 cordeiro_inf_me_jabo.pdf: 2210228 bytes, checksum: c54245ee348cebaa75204af69c942d9d (MD5) / Made available in DSpace on 2018-09-04T13:04:44Z (GMT). No. of bitstreams: 1 cordeiro_inf_me_jabo.pdf: 2210228 bytes, checksum: c54245ee348cebaa75204af69c942d9d (MD5) Previous issue date: 2018-07-13 / Outra / A Batata-doce é um alimento versátil, de fácil aquisição e produção, entretanto, as raízes apresentam inconvenientes como desuniformidade, descasque e rápido escurecimento após o corte, por isso, esse vegetal mostra-se um produto com características a serem superadas pelo processamento mínimo. O uso de agentes antioxidantes e/ou tratamento térmico tem apresentado efeitos satisfatórios na qualidade pós-colheita de produtos hortícolas. Os ácidos cítrico e ascórbico atuam na inativação de enzimas responsáveis pelo escurecimento, devido à redução de pH e ação antioxidante, respectivamente. O tratamento térmico moderado que age na inativação de enzimas do escurecimento sem alterar a textura do vegetal. Nesse contexto, o objetivo desse estudo foi avaliar o efeito do ácido cítrico, ascórbico e tratamento térmico em diferentes concentrações e tempos na qualidade de batata-doce minimante processadas. As raízes de casca rosada e polpa amarela, foram, higienizadas, descascadas e feitos cortes transversais ao eixo principal obtendo rodelas de 1 cm de espessura, que foram submetidas a diferentes tratamentos, à saber, imersão em soluções de ácido citrico (AC) à 0, 1, 2 e 3% por 1 min; ácido ascórbico (AA) à 0, 1, 2 e 3% por 1min e tratamento térmico (TT) à 50°C por 0, 1, 3 e 5 min. Em seguida as batatas-doce foram centrifugadas e armazenadas em bandejas de tereftalado de polietileno (PET) a temperatura de 5 °C e 85% UR por um período de 8 dias. A cada 2 dias avaliou-se a perda acumulada de massa fresca, firmeza, índice de brancura, o pH, acidez titulável, sólidos solúveis, atividade respiratória. Amostras foram congeladas e armazenadas para análises posteriores de compostos fenólicos, atividade das enzimas peroxidase (POD), polifenoloxidase (PPO) e açucares solúveis. Batata-doce minimamente processada tratadas com 2% de ácido cítrico mostraram melhores resultados no escurecimento enzimático e qualidade do vegetal, enquanto o ácido ascórbico na concentração de 2%, apresentou melhor resultado na diminuição da atividade enzimática e qualidade do vegetal. O tratamento térmico a 50°C por 3 min, mostrou-se eficiente na qualidade de batata-doce minimamente processada. / Sweet potato is a versatile food, easy to acquire and produce, however, the roots present disadvantages such as unevenness, peeling and fast darkening after cutting, so this vegetable shows a product with characteristics to be overcome by the minimally processed. The use of antioxidants and / or heat treatment has shown satisfactory effects on the post-harvest quality of vegetables. The citric and ascorbic acids act in the inactivation of enzymes responsible for darkening, due to the reduction of pH and antioxidant action, respectively. The moderate heat treatment that acts in the inactivation of darkening enzymes without changing the texture of the vegetable. Therefore, this study aims to evaluate the effect of the acids citric and ascorbic combine with heat treatment at different concentrations and times in the quality of sweetened sweet potato processed. The roots with rosy peel and yellow pulp were cleaned, peeled and cut transversally around the principal axis, obtaining slices with 1 cm of thickness. The slices were submitted to different treatments, namely immersion in citric acid solutions (AC) at 0, 1, 2 and 3 % for 1 min; ascorbic acid (AA) at 0, 1, 2 and 3 % for 1min and, heat treatment (TT) at 50 °C for 0 (immersion in water at room temperature), 1, 3 and 5 min. Then, the pretreated sweet potatoes were centrifuged and stored in polyethylene terephthalate trays (pet) at 5°c and 85±5 % RH for a period of 8 days. Every 2 days the loss of accumulated fresh mass, firmness, whiteness index, pH titratable acidity, soluble solids and respiratory activity were evaluated. Samples were frozen and stored for further analysis of phenolic compounds, peroxidase enzyme activity (POD), polyphenoloxidase (PPO) and soluble sugars. The acid citric concentration of 2% provided the best whiteness index of the slices. Minimally processed sweet potato treated with 2% citric acid presented better results in enzymatic darkening and vegetable quality, while ascorbic acid at 2% concentration showed better results in the decrease of the enzymatic activity and the quality of the vegetable. The heat treatment at 50 °C for 3 min was efficient in the quality of the minimally processed sweet potato.

FONTENELE, Maria Alves. Conservação pós-colheita do bacuri sob condições ambiente e refrigeração associada à atmosfera modificada. 2007. 138 f. : Dissertação (mestrado) - Universidade Federal do Ceará,Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2007, / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-17T15:32:55Z No. of bitstreams: 1 2007_dis_mafontenele.pdf: 762859 bytes, checksum: 9b4ae0982f4245ee130a56173754c103 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-17T15:33:10Z (GMT) No. of bitstreams: 1 2007_dis_mafontenele.pdf: 762859 bytes, checksum: 9b4ae0982f4245ee130a56173754c103 (MD5) / Made available in DSpace on 2016-06-17T15:33:10Z (GMT). No. of bitstreams: 1 2007_dis_mafontenele.pdf: 762859 bytes, checksum: 9b4ae0982f4245ee130a56173754c103 (MD5) Previous issue date: 2007 / This work had for objectives to verify through the characterization of fruits of the bacuri tree of the Area of the North Middle, which the best atmosphere conditions, of times and storage temperatures, to prolong the life post-harvest of the bacuri (Platonia insignis Mart) for commercialization in natura. The fruits picked in the plant, stored under modified atmosphere they presented great appearance it expresses and it interns until the end of the experiment (25 days), while stored them under atmosphere it adapts they had your appearance it expresses committed after the sixth day, however your internal appearance was satisfactory until the end of experiment. A mass loss it was larger in the fruits without film, with losses of up to 47% to the 25 days of storage, against 8% in the fruits with film. The physical-chemical quality of the pulp was little affected during the storage with prominence for the total soluble solids that presented smaller percentile in the fruits with film. The fruits picked in the plant, stored 7 ºC in modified atmosphere they had your appearance it expresses committed after 20 days, for offenses for the cold, while in the temperatures of 9 and 11 ºC useful life was of 36 days. The coloration of the fruits just developed of clear green for yellow in the temperatures of 9 and 11 ºC, and to 11 ºC the coloration reached a larger intensity. The quality of the pulp practically was not affected by the storage temperatures. The fruits been hit after you/they fall of the plant, stored the temperature it adapts and modified atmosphere had your appearance it expresses committed in the nineteenth day of storage and the intern after 21 days, already for the fruits stored under refrigeration and modified atmosphere, the appearance expresses it was committed to the 28 days of storage, in spite of presenting satisfactory internal appearance until the thirtieth fifth day. The mass loss was of 7.74% and 2.17%, in the fruits stored 25 ºC and 12 ºC, respectively. The fruits storage the temperature adapts they had revenue around 16%, while, that the fruits stored under refrigeration the revenue it was of 15%. The values of SST decreased during the storage in the two appraised temperatures. After 35 days of storage to 25 ºC the fruits presented 12.12 ºBrix on average, while to 12 ºC after 42 days of storage presented a value of 11.28 ºBrix. The values of the pH presented little variation through the time in the two storage conditions and the AT obtained larger variation in the storage to 25 ºC. The relationship SST/AT presented considerable variations among I begin him/it and the end in the two storage types, being more intense in the storage the temperature adapts. The fruits presented low tenors of phenolic compounds in all the fractions characterizing the bacuri pulp as little astringent, demonstrating potential so much for consumption in natura, besides little vitamin tenor C, in the two storage conditions. / Este trabalho teve por objetivos verificar através da caracterização de frutos do bacurizeiro da Região do Meio Norte, quais as melhores condições de atmosfera, de tempos e temperaturas de armazenamento, para prolongar a vida pós - colheita do bacuri (Platonia insignis Mart) para comercialização in natura. Os frutos colhidos na planta, armazenados sob atmosfera modificada apresentaram ótima aparência externa e interna até o final do experimento (25 dias), enquanto que os armazenados sob atmosfera ambiente tiveram sua aparência externa comprometida após o sexto dia, entretanto sua aparência interna foi satisfatória até o final do experimento. A perda de massa foi maior nos frutos sem filme, com perdas de até 47% aos 25 dias de armazenamento, contra 8% nos frutos com filme. A qualidade físico-quimica da polpa foi pouco afetada durante o armazenamento com destaque para os sólidos solúveis totais que apresentaram menor percentual nos frutos com filme. Os frutos colhidos na planta, armazenados a 7 ºC em atmosfera modificada tiveram sua aparência externa comprometida após 20 dias, por injúrias pelo frio, enquanto que nas temperaturas de 9 e 11 ºC a vida útil foi de 36 dias. A coloração das frutas evoluiu de verde claro para amarelo apenas nas temperaturas de 9 e 11 ºC, sendo que a 11 ºC a coloração atingiu uma maior intensidade. A qualidade da polpa praticamente não foi afetada pelas temperaturas de armazenamento. Os frutos apanhados após caírem da planta, armazenados a temperatura ambiente e atmosfera modificada tiveram sua aparência externa comprometida no décimo nono dia de armazenamento e a interna após 21 dias. Já para os frutos armazenados sob refrigeração e atmosfera modificada, a aparência externa foi comprometida aos 28 dias de armazenamento, apesar de apresentar aparência interna satisfatória até o trigésimo quinto dia. A perda de massa foi de 7,74% e 2,17%, nos frutos armazenados a 25 ºC e 12 ºC, respectivamente. Os frutos armazenamento a temperatura ambiente tiveram rendimento em torno de 16%, enquanto, que os frutos armazenados sob refrigeração o rendimento foi de 15%. Os valores dos SST decresceram durante o armazenamento nas duas temperaturas avaliadas. Após 35 dias de armazenamento a 25 ºC os frutos apresentaram em média 12,12 ºBrix, enquanto que a 12 ºC após 42 dias de armazenamento apresentaram um valor de 11,28 ºBrix. Os valores de pH apresentaram pouca variação através do tempo nas duas condições de armazenamento e a AT obteve maior variação no armazenamento a 25 ºC. A relação SST/AT apresentou variações consideráveis entre o inicio e o final nos dois tipos de armazenamento, sendo mais intenso no armazenamento a temperatura ambiente. Os frutos apresentaram baixos teores de compostos fenólicos em todas as frações caracterizando a polpa de bacuri como pouco adstringente, demonstrando potencial para consumo in natura, além de pouco teor de vitamina C, nas duas condições de armazenamento.