The major objective of the research was to improve lychee postharvest management, through a greater understanding of mechanical injury and moisture loss. Mechanical injury is a known cause of postharvest loss in lychee, but previously published information has been limited to broad observations. In this study, the symptoms of mechanical damage in lychee were defined, including quantitative measurement of colour changes. Impact injury caused protuberance tip darkening, cracking of the pericarp and significant changes in skin colour. Compression also typically caused tip darkening, and severe loads were capable of puncture, shape distortion and skin cracking. Abrasion and vibration injuries were characterised by strong yellowing of pericarp colour, possibly due to the leakage of cell contents onto the fruit surface. Vibration also caused significant darkening and loss of colour saturation. Vibration has not previously been mentioned as an issue in lychee postharvest management, but appeared to be as important a problem as desiccation browning at the wholesale level, both in incidence and severity. Mechanically damaged fruit consistently showed increased ethylene and carbon dioxide synthesis, and moisture loss was increased by up to 30%. Some significant changes in skin biochemistry and cuticle properties were also detected. The study of damaged tissue by SEM revealed distinctive patterns of surface tissue disruption. Open pericarp cracking was a particularly detrimental injury, causing significantly increased electrolyte leakage and rapid pathogen development. The effects of load characteristics, such as magnitude, method of application, site, repetition and cushioning, on the extent of damage were defined. Fruit characteristics such as cultivar, gross morphology, temperature, hydration and surface wetness were shown to significantly affect damage levels. Small seed size was correlated with increased cracking susceptibility. Fruit surface wetness exacerbated vibration or abrasion damage. Turgid fruit were less susceptible to vibration and abrasion damage, but showed increased susceptibility to impact cracking. Previously neglected aspects of desiccation browning research were studied, including cultivar and maturity effects, sites of moisture loss and the role of air currents. Cultivar effects on moisture loss were obscured by pre-harvest factors, but consistent cultivar differences were detected in desiccation browning, possibly related to skin thickness. In contrast, maturity levels over a marketable range had little effect on weight loss or browning. Moisture was lost fairly evenly over the fruit surface, but poor postharvest handling appeared to massively increase loss from the protuberance tips. Moisture loss was shown to substantially increase ethylene synthesis. The crucial role of air currents in exacerbating lychee moisture loss was emphasised, and the relationship between air speed and weight loss was defined. The research contributed to a greater understanding of the processes of mechanical damage and moisture loss in lychee, leading to improved protocols for the postharvest management of the fruit. Improved management of mechanical damage and moisture loss will ultimately improve fruit quality and reduce postharvest losses, hence increasing returns to industry.

The major objective of the research was to improve lychee postharvest management, through a greater understanding of mechanical injury and moisture loss. Mechanical injury is a known cause of postharvest loss in lychee, but previously published information has been limited to broad observations. In this study, the symptoms of mechanical damage in lychee were defined, including quantitative measurement of colour changes. Impact injury caused protuberance tip darkening, cracking of the pericarp and significant changes in skin colour. Compression also typically caused tip darkening, and severe loads were capable of puncture, shape distortion and skin cracking. Abrasion and vibration injuries were characterised by strong yellowing of pericarp colour, possibly due to the leakage of cell contents onto the fruit surface. Vibration also caused significant darkening and loss of colour saturation. Vibration has not previously been mentioned as an issue in lychee postharvest management, but appeared to be as important a problem as desiccation browning at the wholesale level, both in incidence and severity. Mechanically damaged fruit consistently showed increased ethylene and carbon dioxide synthesis, and moisture loss was increased by up to 30%. Some significant changes in skin biochemistry and cuticle properties were also detected. The study of damaged tissue by SEM revealed distinctive patterns of surface tissue disruption. Open pericarp cracking was a particularly detrimental injury, causing significantly increased electrolyte leakage and rapid pathogen development. The effects of load characteristics, such as magnitude, method of application, site, repetition and cushioning, on the extent of damage were defined. Fruit characteristics such as cultivar, gross morphology, temperature, hydration and surface wetness were shown to significantly affect damage levels. Small seed size was correlated with increased cracking susceptibility. Fruit surface wetness exacerbated vibration or abrasion damage. Turgid fruit were less susceptible to vibration and abrasion damage, but showed increased susceptibility to impact cracking. Previously neglected aspects of desiccation browning research were studied, including cultivar and maturity effects, sites of moisture loss and the role of air currents. Cultivar effects on moisture loss were obscured by pre-harvest factors, but consistent cultivar differences were detected in desiccation browning, possibly related to skin thickness. In contrast, maturity levels over a marketable range had little effect on weight loss or browning. Moisture was lost fairly evenly over the fruit surface, but poor postharvest handling appeared to massively increase loss from the protuberance tips. Moisture loss was shown to substantially increase ethylene synthesis. The crucial role of air currents in exacerbating lychee moisture loss was emphasised, and the relationship between air speed and weight loss was defined. The research contributed to a greater understanding of the processes of mechanical damage and moisture loss in lychee, leading to improved protocols for the postharvest management of the fruit. Improved management of mechanical damage and moisture loss will ultimately improve fruit quality and reduce postharvest losses, hence increasing returns to industry.

Tese (doutorado)—Universidade de Brasília, Faculdade de Agronomia e Medicina Veterinária, Programa de Pós-Graduação em Agronomia, 2016. / Submitted by Fernanda Percia França (fernandafranca@bce.unb.br) on 2016-08-25T19:31:15Z No. of bitstreams: 1 2016_ValdeirGonçalvesDias.pdf: 2584521 bytes, checksum: a286432d09b6732f2e964db18f246de8 (MD5) / Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2016-11-03T11:50:55Z (GMT) No. of bitstreams: 1 2016_ValdeirGonçalvesDias.pdf: 2584521 bytes, checksum: a286432d09b6732f2e964db18f246de8 (MD5) / Made available in DSpace on 2016-11-03T11:50:55Z (GMT). No. of bitstreams: 1 2016_ValdeirGonçalvesDias.pdf: 2584521 bytes, checksum: a286432d09b6732f2e964db18f246de8 (MD5) / O baixo percentual no vingamento de frutos é um dos principais problemas nos cultivos de Lichia no Brasil. Portanto, foram desenvolvidos trabalhos com o objetivo de avaliar a resposta da lichieira ao uso da aplicação de auxina e ureia via foliar na fixação e tamanho de frutos, visando melhoras tanto na fixação quanto no calibre de frutos. Os experimentos foram implantados em um pomar comercial, localizado na fazenda Paraíso, município do Rio Paranaíba-MG. Foi utilizado um delineamento em blocos casualizados (DBC), dividido em 3 ensaios com 12 plantas, um total de 36 plantas, em cada teste uma massa de frutos de 2g, 4g e 6g, em cada massa quatro doses 0, 20, 40 e 60 mg.dm-3 de auxina sintética (3,5,6 TPA) e 3 repetições. Foram selecionadas plantas de lichieira cultivar “Bengal”, uniformes de acordo com porte, potencial produtivo, estádio de florescimento, condição fitossanitária e nutricional, clones, oriundas da técnica de alporquia, com idade aproximada de 12 anos, plantadas em espaçamento 8 X 6m totalizando (208 plantas/ha). As aplicações foram feitas na forma de pulverização, com o auxílio de uma bomba costal e o volume de calda aplicado foi de 5 litros / plantas. Foram avaliados: diâmetro (mm) e número de frutos por panícula. As avaliações foram realizadas semanalmente no período compreendido entre a 4ª semana após a antese e se estendeu até o ponto de colheita comercial. No segundo experimento o delineamento experimental adotado foi (DBC) em arranjo fatorial 12x4, dividido em 12 avaliações, quatro quadrantes (Oeste, Norte, Leste e Sul) com três repetições. Foram selecionadas 9 plantas de lichieira, levando em consideração todos os fatores anteriormente citados. No terceiro experimento utilizou-se o DBC, com10 plantas por bloco e seis repetições. Cada bloco recebeu cinco doses de ureia, 00 (testemunha); 60; 120; 180 e 240 gramas por plantas (g de ureia.plantas-1). Foram selecionadas 60 plantas de lichieira cultivar Bengal, respeitando a uniformidade de acordo com porte, potencial produtivo, estádio de florescimento, condição fitossanitária e nutricional. Os dados coletados foram submetidos à análise de variância para avaliação da significância do efeito dos tratamentos por meio do teste de F. As medidas encontradas foram comparadas entre si, pelo teste de Scott-Knott ou Tukey, ao nível de 5% de probabilidade e regressão para doses de nitrogênio, através do software SISVAR. As aplicações com auxina sintética (3,5,6 TPA), de maneira geral resultaram no aumento significativo do diâmetro de frutos em 17,5% e 144,6% para o número de frutos, quando comparado com as testemunhas. Em relação a interferência solar para crescimento do fruto o melhor quadrante é oeste com diâmetro médio 13,30; 8,67 e 5,13% superior aos quadrantes norte, sul e leste respectivamente. Para fixação dos frutos o quadrante leste com 128,46; 42,62 e 40,16% superior aos quadrantes norte, oeste e sul respectivamente. Para o uso de ureia com aplicação via foliar a dose de 120g de ureia.planta-1 mostrou significativamente superior em todas as variáveis analisadas. Foi observado para fixação de frutos na colheita incremento superior a 100% comparado à testemunha, além de aumentar o número de frutos de maior calibre. _______________________________________________________________________________________________ ABSTRACT / Low percentage in fruit set is a major trouble in litchi cultivation in Brazil. Therefore, we have carried out studies in order to evaluate the response of litchi to foliar applications of exogenous auxin and urea in fruit set and size, aiming for improvements in both aspects. Three experiments were implemented in a commercial orchard located at Paraíso farm, in Rio Paranaíba - MG municipality. Randomized block design (RBD) divided into 3 trials with 12 plants with a total of 36 plants, in each trial a fruit mass of 2g, 4g and 6g, and in each mass four doses 0, 20 , 40 and 60 mg.dm-³ of synthetic auxin (3,5,6 TPA) with 3 repetitions were used. Litchi plants of ‘Bengal’ cultivar were selected according to similarities in their size, productive potential, flowering stage, plant health and nutritional status. They were clones from the air layering technique with approximately 12 years old, planted in a spacing of 8 x 6 m, totaling 208 plants per hectare. Applications were made with the aid of a backpack sprayer and a spray volume of 5 liters per plant was used. We evaluated the diameter (mm) and number of fruit per panicle. Evaluations were performed weekly starting from the 4th week after anthesis until the commercial harvest point. The second experiment also had a randomized block design (RBD) in a factorial arrangement (12x4), divided into 12 evaluations: four quadrants (West, North, East and South) with three replications. We selected 9 plants of litchi, taking into account all of the aforementioned factors. In the third experiment we also used RBD, with 10 plants per block and six replications. Each block received five doses of urea: 00 (control); 60; 120; 180 and 240 grams of urea per plant. We selected 60 litchi plants of cultivar 'Bengal', also in accordance to their uniformity of size, productive potential, flowering stage, plant health and nutritional condition. Data was subjected to analysis of variance to assess the significance of the effect of treatments by means of an F test. Measures were compared by either the Scott-Knott or Tukey test at 5% probability, with a regression for nitrogen by means of SISVAR software. In general, applications of synthetic auxin (3,5,6 TPA) resulted in significant increase in fruit diameter by 17.5% and 144.6% in the number of fruit compared to control. Concerning the solar interference in fruit growth, the best quadrant is the West one, with an average diameter of 13.30%, 8.67% and 5.13% higher than the North, South and East quadrants, respectively. For fruit set, however, the East quadrant was superior, being 128.46%, 42.62% and 40.16% higher than the North, West and South quadrants, respectively. For foliar application of urea, the dose of 120 g ureia.plant-1 was significantly better for all the variables analyzed. Thus, during harvest it was observed that fruit set had increased by more than 100% compared to the control group, besides having increased the number of fruit of greater caliber.

Orientador: Antonio Baldo Geraldo Martins / Banca: José Antônio Alberto da Silva / Banca: Carlos Ruggiero / Banca: Dalmo Lopes de Siqueira / Banca: João Alexio Scarpare Filho / Resumo: O trabalho foi realizado nas Fazendas Santo Antônio e Jurupema, localizadas no Município de Taquaritinga -SP, Brasil, de abril de 2003 a dezembro de 2005, com o objetivo de estudar a influência da temperatura, anelamento e alguns reguladores de crescimento sobre a floração e a produção de lichieiras cultivar Bengal. Foram registrados dados de produção e temperaturas, precipitação e horas acumuladas com temperaturas inferiores a 15,5° C, e correlacionados para entender o grau de interação. Foi realizado anelamento de ramos de diferentes diâmetros, para conhecer o seu efeito sobre a floração e a frutificação. O anelamento não teve efeito sobre a brotação vegetativa após a colheita, mas as maiores concentrações de PBZ reduziram significativamente a brotação vegetativa e o comprimento dos ramos. O uso de ANA provocou queimaduras nas inflorescências e queda de frutos, mas os que permaneceram, não apresentaram alterações nas características físicas e nos sólidos solúveis. Não foi observado efeito significativo da aplicação de GA3, sobre a fixação de frutos. A queda de frutos, a partir de uma massa de 2 g até a colheita, é de 50%. / Abstract: The work was carried through on Santo Antonio and Jurupema farms, located in Taquaritinga, São Paulo State, Brazil, in the period from April 2003 to December 2005, with the objective to study the influence of temperature, girdling and some growth regulators on the flowering, fruiting and production of lychee trees cultivar Bengal. It was registered production data and temperatures, precipitation and accumulated hours with inferior temperatures to 15.5°C, and correlated to understand the interaction degree. Girdling of branches of different diameters was carried through, to know its effect on the flowering and fruiting. The girdling didn't have effect on the vegetative flushes after the harvest, but the biggest concentrations of PBZ reduce the vegetative flushes and the length of shoots significantly. Spray with NAA provoked burns in the panicles and drop of fruits, but the ones that had remained did not have present alterations in the characteristics and in the soluble solids. Beneficial effect of the application of GA3 on the fruit set was not observed. The drop of fruits, starting from a weight of 2 g to the harvest, is of 50%. / Doutor

Made available in DSpace on 2014-06-11T19:33:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-13Bitstream added on 2014-06-13T21:06:45Z : No. of bitstreams: 1 hojo_etd_dr_jabo.pdf: 1539570 bytes, checksum: 9a8c4375124457a8e811faf5f3693cc6 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Visando prolongar a vida útil da lichia, principalmente quanto à manutenção da cor e da qualidade, executaram-se experimentos para avaliar a eficiência dos tratamentos hidrotérmico e com solução de ácido clorídrico (HCl); do armazenamento sob refrigeração, em atmosfera controlada e em diferentes embalagens plásticas e de coberturas com quitosana. No Experimento I, testou-se a imersão em HCl a 0,087M por 6 minutos; o tratamento hidrotérmico por imersão a 52ºC por 1 minuto, seguido de resfriamento em água a 10ºC por 6 minutos; e o tratamento hidrotérmico com resfriamento em HCl a 0,087M a 10ºC por 6 minutos. O tratamento hidrotérmico seguido de resfriamento em HCl conservou a coloração dos frutos até o 3º dia, e a polpa com qualidade adequada até o 12º dia. No Experimento II, utilizou-se o melhor tratamento do experimento anterior (hidrotérmico com resfriamento em HCl) e testaramse diferentes temperaturas de armazenamento: 2ºC (91% UR); 5ºC (98% UR); 10ºC (80% UR); e 20ºC (70% UR). Os frutos foram analisados após 1, 4, 7, 10, 13, 16, 19, 22 e 25 dias. O armazenamento de lichia a 5 ºC manteve a boa aparência por até 13 dias e a qualidade da polpa até o final do período, 25 dias. O armazenamento a 2 ºC levou a maiores prejuízos na aparência. As temperaturas, de 10 ºC e 20 ºC, não foram efetivas para a manutenção da cor vermelha da casca. No Experimento III, foi testado o efeito da atmosfera controlada, associado aos melhores tratamentos dos experimentos anteriores. Os frutos foram armazenados a 5ºC e 94% UR, em atmosfera controlada contendo 5%, 10%, 20% e 80% de O2, com avaliações após 0 (inicial), 3, 7, 14, 21, 28 dias. As lichias de todos os tratamentos mantiveram a boa qualidade da polpa por até 21 dias, com os frutos sob atmosfera com 5% de O2, apresentando menor escurecimento da casca. As lichias apresentaram escurecimento da casca... / Aiming to extend litchi life, especially regarding to color and quality maintenance, experiments were performed to evaluate the treatment efficiency under heat and using hydrochloric acid solution (HCl), refrigerated storage, controlled atmosphere, different plastic containers, and chitosan coatings. In Experiment I, it was tested immersion in 0,087M HCl for 6 minutes; hydrothermal treatment by immersion at 52ºC for 1 minute, followed by water cooling at 10ºC for 6 minutes; and hydrothermal treatment with 0,087M HCl cooling at 10 ºC for 6 minutes. Hydrothermal treatment followed by HCl cooling preserved fruit color until the 3rd day and adequate pulp quality until the 12th day. In Experiment II, it was used the best treatment in the previous experiment (hydrothermal with HCl cooling) and different storage temperatures were tested: 2ºC (91% RH), 5ºC (98% RH), 10ºC (80% RH), and 20ºC (70% RH). Fruits were analyzed after 1, 4, 7, 10, 13, 16, 19, 22, and 25 days. Storage at 5ºC kept the good fruit appearance for up to 13 days, and pulp quality until the 25th day. The 2ºC led to to ligher losses in appearance. The temperatures of 10ºC and 20ºC, were not effective for maintaining the red color of the skin. In Experiment III, the effects of controlled atmosphere combined with improved treatments of previous experiments were tested. Fruits were stored at 5ºC and 94% RH in a controlled atmosphere containing 5%, 10%, 20% and 80% O2, with evaluations after 0 (initial), 3, 7, 14, 21, 28 days. Litchis in all treatments maintained good pulp quality for up to 21 days, with the fruits under a 5% O2 atmosphere showing a lower skin browning. Litchis showed over 50% skin browning after 7 days. In Experiment IV, different concentrations of CO2 (0%, 5%, 10%, 15%, and 20%) combined with the best concentration in the previous experiment, 5% O2, were tested... (Complete abstract click electronic access below)

Orientador: José Fernando Durigan / Banca: Ben-Hur Mattiuz / Banca: Ricardo Alfredo Kluge / Banca: Jairo Osvaldo Cazetta / Banca: Marcos David Ferreira / Resumo: Visando prolongar a vida útil da lichia, principalmente quanto à manutenção da cor e da qualidade, executaram-se experimentos para avaliar a eficiência dos tratamentos hidrotérmico e com solução de ácido clorídrico (HCl); do armazenamento sob refrigeração, em atmosfera controlada e em diferentes embalagens plásticas e de coberturas com quitosana. No Experimento I, testou-se a imersão em HCl a 0,087M por 6 minutos; o tratamento hidrotérmico por imersão a 52ºC por 1 minuto, seguido de resfriamento em água a 10ºC por 6 minutos; e o tratamento hidrotérmico com resfriamento em HCl a 0,087M a 10ºC por 6 minutos. O tratamento hidrotérmico seguido de resfriamento em HCl conservou a coloração dos frutos até o 3º dia, e a polpa com qualidade adequada até o 12º dia. No Experimento II, utilizou-se o melhor tratamento do experimento anterior (hidrotérmico com resfriamento em HCl) e testaramse diferentes temperaturas de armazenamento: 2ºC (91% UR); 5ºC (98% UR); 10ºC (80% UR); e 20ºC (70% UR). Os frutos foram analisados após 1, 4, 7, 10, 13, 16, 19, 22 e 25 dias. O armazenamento de lichia a 5 ºC manteve a boa aparência por até 13 dias e a qualidade da polpa até o final do período, 25 dias. O armazenamento a 2 ºC levou a maiores prejuízos na aparência. As temperaturas, de 10 ºC e 20 ºC, não foram efetivas para a manutenção da cor vermelha da casca. No Experimento III, foi testado o efeito da atmosfera controlada, associado aos melhores tratamentos dos experimentos anteriores. Os frutos foram armazenados a 5ºC e 94% UR, em atmosfera controlada contendo 5%, 10%, 20% e 80% de O2, com avaliações após 0 (inicial), 3, 7, 14, 21, 28 dias. As lichias de todos os tratamentos mantiveram a boa qualidade da polpa por até 21 dias, com os frutos sob atmosfera com 5% de O2, apresentando menor escurecimento da casca. As lichias apresentaram escurecimento da casca... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Aiming to extend litchi life, especially regarding to color and quality maintenance, experiments were performed to evaluate the treatment efficiency under heat and using hydrochloric acid solution (HCl), refrigerated storage, controlled atmosphere, different plastic containers, and chitosan coatings. In Experiment I, it was tested immersion in 0,087M HCl for 6 minutes; hydrothermal treatment by immersion at 52ºC for 1 minute, followed by water cooling at 10ºC for 6 minutes; and hydrothermal treatment with 0,087M HCl cooling at 10 ºC for 6 minutes. Hydrothermal treatment followed by HCl cooling preserved fruit color until the 3rd day and adequate pulp quality until the 12th day. In Experiment II, it was used the best treatment in the previous experiment (hydrothermal with HCl cooling) and different storage temperatures were tested: 2ºC (91% RH), 5ºC (98% RH), 10ºC (80% RH), and 20ºC (70% RH). Fruits were analyzed after 1, 4, 7, 10, 13, 16, 19, 22, and 25 days. Storage at 5ºC kept the good fruit appearance for up to 13 days, and pulp quality until the 25th day. The 2ºC led to to ligher losses in appearance. The temperatures of 10ºC and 20ºC, were not effective for maintaining the red color of the skin. In Experiment III, the effects of controlled atmosphere combined with improved treatments of previous experiments were tested. Fruits were stored at 5ºC and 94% RH in a controlled atmosphere containing 5%, 10%, 20% and 80% O2, with evaluations after 0 (initial), 3, 7, 14, 21, 28 days. Litchis in all treatments maintained good pulp quality for up to 21 days, with the fruits under a 5% O2 atmosphere showing a lower skin browning. Litchis showed over 50% skin browning after 7 days. In Experiment IV, different concentrations of CO2 (0%, 5%, 10%, 15%, and 20%) combined with the best concentration in the previous experiment, 5% O2, were tested... (Complete abstract click electronic access below) / Doutor

Thesis (M.Sc. Agriculture (Horticulture)) -- University of Limpopo, 2022 / The most common postharvest limitation of litchi fruit is pericarp browning, which leads to consumer rejection of the solid fruit in the market even when the edible portion is not affected. Previously, sulphur dioxide (SO2) fumigation was used to control the browning and extend shelf life of litchi fruit. However, SO2 fumigation leaves undesirable residues, alters the fruit taste and may results in health hazards for consumers. An alternative method, namely, minimal processing was used to control pericarp browning and curb postharvest losses in litchi. Litchi fruit were harvested at two maturity stages (early harvest; 120 days after full bloom (DAFB), late harvest; 130 DAFB), peeled and immersed for two (2) minutes in three (3) solutions that represented treatments, namely 1) 1% citric acid 2) 1% calcium lactate and 3) a combination of citric acid and calcium lactate both at 1% measure. The untreated arils were dipped in sodium hypochloride (NaOCl) solution for 1 minute and represented the control samples. The treated arils were packed in sterilized clamshell containers and stored at 1±0.5°C and 95% relative humidity for 12 days, then held at 10±0.5°C for 2 days for shelf life study. As a result of the interaction effect of harvest stages and postharvest pre-treatments, least mass loss percentage (1.32%), juice leakage (1.8 ml per 120 g of fruit) and pH (4.18) was observed in litchi arils harvested late and treated with 1% citric acid only under cold storage. Under shelf life study, H2 control samples presented lower mass loss (2.8%) and juice leakage (4.2 ml per 120 g of fruit). At the end of cold storage, litchi arils harvested early and treated with 1% citric acid combined with 1% calcium lactate presented better tissue strength (56.0 N) and radical scavenging activity (36.6 mmol AAE/mL), while those harvested late presented higher ascorbic acid content (72.9 µg/mL), least microbial population and total colour change (3.5). However, at the end of shelf life storage, litchi arils harvested early and treated with 1% citric acid combined with 1% calcium lactate presented lower (3.1) total change in colour. Overall, harvesting the fruit late and treating with citric acid alone or combined with calcium lactate showed the potential of maintaining better aril quality with least microbial population for up to 12 days under 1±0.5°C storage, whereas harvesteing the fruit early and treating with citric acid alone or combined with calcium lactate showed the potential of maintaining better aril quality under shelf life storage. Keywords: Litchi chinesis sonn; calcium lactate; citric acid; maturity; fresh-cut. / Agricultural Research Council (ARC), National Research Foundation (NRF) and Agri-Seta

L'amélioration de la production du litchi et du manguier nécessite de mieux comprendre et simuler l'effet du stress hydrique, fréquent en situations réelles en champ, sur les échanges gazeux. Un état des lieux des connaissances actuelles autour du déterminisme du fonctionnement des stomates et de la photosynthèse a été dressé. Expérimentalement, la stratégie adoptée par le manguier et le litchi face au stress, puis l'effet du stress à long terme sur la capacité photosynthétique, ont été étudiés. Le manguier, plus vulnérable à la cavitation que le litchi, ferme ses stomates plus précocement. La capacité photosynthétique a diminué en relation avec de la photoprotection et une réduction de l'activité puit. Le pool d'azote foliaire n'a pas été atteint, mais la concentration surfacique en azote a augmenté chez le litchi. La transpiration du manguier a été simulée, sur la base d'un modèle hydraulique. Des pistes de modélisation empiriques de la capacité photosynthétique ont été proposées.

Thesis (M.Com.(Agricultural Economics))--University of Pretoria, 2009. / Includes bibliographical references

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-08-21T11:22:50Z No. of bitstreams: 1 MARCO TÚLLIO LIMA DUARTE - TESE (PPGEP) 2018.pdf: 2250276 bytes, checksum: fbe9c7f829118eade9f7ed9fba1f9644 (MD5) / Made available in DSpace on 2018-08-21T11:22:50Z (GMT). No. of bitstreams: 1 MARCO TÚLLIO LIMA DUARTE - TESE (PPGEP) 2018.pdf: 2250276 bytes, checksum: fbe9c7f829118eade9f7ed9fba1f9644 (MD5) Previous issue date: 2018-02 / A lichia (Litchi chinensis) é um fruto nativo da Ásia, sendo considerada a rainha das frutas. No Brasil, sua introdução se deu como planta ornamental e somente a partir da década de 70, teve seu consumo ampliado. Devido ao seu elevado valor comercial, curto período de safra e alta perecibilidade, uma das estratégias de ampliação da sua oferta é a sua desidratação e posterior uso do pó em bebidas lácteas probióticas. Dessa forma, objetivou-se no presente estudo a produção de lichia em pó através da liofilização, avaliando a estabilidade do pó durante o armazenamento e a elaboração de uma bebida láctea probiótica. Foram elaboradas três formulações de maltodextrina, nas concentrações de 15, 20 e 25%. Essas formulações foram previamente caracterizadas, juntamente com a polpa integral, foram avaliados seus comportamentos reológicos e em seguida, liofilizadas na temperatura de –40 °C durante 48 h. Após a caracterização dos pós, a melhor amostra foi submetida a análises de isotermas de adsorção de água, nas temperaturas de 30 e 40°C, analisada em microscopia eletrônica de varredura e armazenada em embalagens laminadas por 60 dias, nas temperaturas de 20, 30 e 40°C, quando foram monitoradas a cada 10 dias suas características, físicas, químicas e físicoquímicas. Adicionalmente, foram processadas bebidas lácteas fermentadas isentas de pó de lichia e nas concentrações de 7, 9 e 11% do pó, que foram caracterizadas quanto aos parâmetros físicos, químicos e físico-químicos. Os resultados obtidos revelaram que as polpas formuladas e desidratadas sofreram alterações quanto aos parâmetros avaliados em todas as amostras, em função da concentração da maltodextrina. A polpa integral e as diferentes formulações exibiram comportamento reológico típico de polpas de frutas, classificando-se como fluido não-newtoniano, de caráter pseudoplástico, cujo melhor ajuste matemático foi com o modelo de Mizrahi-Berk. O processo de liofilização refletiu em alterações dos parâmetros analisados, tendo o pó adicionado de 25% de maltodextrina exibido as melhores características dentre amostras avaliadas. A análise das isotermas de adsorção de água foram determinadas como tipo III e o melhor modelo matemático para descrição dos dados experimentais foi o de GAB, por exibir maiores valores de R2 e menores índices de erros médios relativos. Quanto à análise da microscopia eletrônica, foi constatado que o pó da lichia exibiu estruturas amorfas e aglomerado de partículas, com rugosidades acentuadas e grande porosidade. Durante o período de armazenamento, a maioria dos parâmetros físicos, químicos e físicoquímicos foram alterados, principalmente em função da temperatura de exposição e as bebidas lácteas probióticas demonstraram diferenças significativas em função da elevação da concentração do pó de lichia adicionado como saborizante. / The lychee (Litchi chinensis) is a fruit native to Asia, being considered the queen of the fruit. In Brazil, its introduction was given as an ornamental plant and only from the decade of 70, had its consumption expanded. Due to its high commercial value, short harvest period and high perishability, one of the strategies to expand their offer is your dehydration and subsequent use of powder in probiotic dairy drinks. Thus, the objective of the present study verified the production of lychee powder by lyophilization, evaluating the stability of powder during storage and prepares a probiotic milk drink. In this way, were drawn up three formulations, added maltodextrin, at concentrations of 15, 20 and 25%. These formulations were previously characterized, along with the integral pulp, evaluated their rheological behavior and then freeze at a temperature of - 40 °C for 48 h. The powders obtained were subsequently characterized and the best sample, subjected to analyzes of adsorption isotherms of water at temperatures of 30 and 40 °C, analyzed in scanning electron microscopy and stored in laminated packaging by 60 days at temperatures of 20, 30 and 40 °C, when were monitored every 10 days, its characteristics, physical, chemical and physico-chemical properties. In addition, were processed fermented dairy drinks free of powder of lychee and at concentrations of 7, 9 and 11% of powder, which were characterized according to the physical, chemical and physico-chemical properties. The results obtained showed that the dehydrated pulps formulated and suffered changes regarding the parameters evaluated in all samples, depending on the concentration of maltodextrin. The integral pulp and the different formulations exhibited rheological behavior typical of fruit pulps, classifying it as non- Newtonian fluid, pseudoplastic character, whose best fit was with the mathematical model of Mizrahi-Berk. The lyophilization process reflected in changes of the parameters analyzed, taking the powder added to 25%maltodextrin displayed the best characteristics among samples. The analysis of adsorption isotherms of water were determined as type III and the best mathematical model for description of the experimental data was the GAB, to display larger values of R2 and lower rates of errors average. Regarding the analysis of electronic microscopy, it was noticed that the powder of the lychee exhibited amorphous structures and particleboard, with pronounced roughness and high porosity. During the storage period, most of the physical, chemical and physico-chemical parameters were altered, mainly in function of the temperature of exposure and the probiotic dairy drinks have demonstrated significant differences depending on the elevation of the concentration of powder of lychee added as flavor.