Thesis (Ph. D.)--Dept. of Crop Science, Faculty of Agriculture, 2005. / Bibliography: leaves 460-487.

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The use of sulphur as a method of postharvest disease control and colour retention in litchis is soon to be restricted by the European Union. It is therefore essential that new postharvest treatments and packaging techniques be developed in order to retain internal and external fruit qualities and thus allow for export. Good litchi quality is not only important for the export market but also for use on the local market. In this study, alternative methods for postharvest quality control were investigated with the aim of extending the litchi storage life to 40 days under modified storage. Packaging the fruit in polypropylene bags significantly decreased fruit water loss and resulted in an increase in shelf life, as determined by red colour and overall rind appearance. There was no distinct advantage of amodified atmosphere. The use of a punnet, lined with absorbent sheeting and placed within the sealed polypropylene bag, further improved the shelf life. The absorbent sheeting reduced the amount of free water and resulted in little pathogen infection, while the punnet was effective in protecting the fruit from damage. It was notable that most water loss occurred within the first 10 days of storage and that the majority would actually take place during the cooling phase. A hydrocooling technique was therefore investigated and was found to not significantly decrease water loss, possibly due to not hydrocooling the fruit for a long enough period of time. Temperature management was extremely important for both colour retention and pathogen control. It was found that treatments stored at 5.5QC showed better colour retention after the 40 days storage than the 1QC storage treatment. The higher storage temperature, however, enhances the potential for postharvest diseases. Three compounds, namely ISR 2000, 'Biosave' and F10, were tested for pathogen control. 'Biosave' showed the best results with the most effective concentration being 100 mill water and good pathogen control occurred when storage was at 10 C. Polyphenol oxidase (PPO) activity in the litchi rind was evaluated as it is thought to be closely related to browning of litchi fruit, probably due to the degradation of phenolics by PPO. Brown fruit had a high PPO activity whilst red fruit had much lower activity. It was also shown that PPO activity decrease over storage time, possibly due to product inhibition of the enzyme. The internal quality of the fruit was determined using the T88: acid ratio of the pulp, as it is well correlated to mean eating quality. For fruit to have excellent taste, it must have a T88: acid ratio of between 31:1 and 60:1. All the fruit had a ratio that met this criterion and would therefore ensure good eating quality. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

In South Africa, a shortage of litchi cultivars to expand the very short harvesting period has seriously threatened the viability of the local export orientated Litchi Industry. Only two cultivars have dominated commercial plantings for more than a century, namely ‘HLH Mauritius’ and ‘McLean’s Red’. The marketing period of litchis from South Africa coincides with large export volumes from competitor countries such as Madagascar, resulting in lower returns for local growers. To address this situation, the late season cultivar ‘Wai Chee’ was imported amongst others from Australia. ‘Wai Chee’ is harvested at a time in South Africa when there is a gap in worldwide litchi production, making the cultivar potentially very profitable. However, its potential and subsequent use in the industry is affected by small fruit size and questionable internal quality. As the South African Litchi Industry is export orientated and the qualities of ‘HLH Mauritius’ fruit currently dictate export requirements, solutions need to be found to improve fruit size and fruit quality in ‘Wai Chee’ litchi. In this study, a number of horticultural manipulation techniques were investigated with the aim of enhancing yield, fruit size and quality in ‘Wai Chee’ litchi. The use of chemical applications of foliar nutrients and plant growth regulators were found to improve certain fruit characteristics in ‘Wai Chee’. Foliar nutrient applications of nitrogen, potassium and calcium during the early stages of fruit set and -development improved fruit set and subsequently yield, and also increased fruit mass, fruit size and flesh mass. Treatments with potassium nitrate (KNOз), calcium nitrate (CaNOз) and calcium metalosate proved to be the most enhancing nutrient applications. Applications of synthetic auxins and auxin-like substances during the 2-3g stage of fruit development improved fruit size, fruit mass and flesh mass in ‘Wai Chee’. The combination treatment of Tipimon® (2,4,5-TP), applied at the 2-3g stage, followed by Maxim® (3,5,6-TPA) a week later, yielded the best results in this regard. With biological practices, pollination was found to have an influence on litchi tree- and fruit characteristics. Pollen source proved to have an influence on fruit set and fruit retention at harvest in ‘Wai Chee’. Initial fruit set was lower when using cross-pollination compared to the use of self-pollination in female flowers of ‘Wai Chee’, whereas final fruit retention was higher with the use of cross-pollinators when compared to retention of fruit with self-pollination. Although some beneficial effects with different pollen donors on fruit characteristics were observed, these effects were not significant, and would therefore necessitate further investigation. Pollen donor effect on quality parameters such as Titratable acid (TA)- and Total Soluble Solid (TSS) content of fruit was not significant. Cultivar differences regarding fruit characteristics and maturation rate were detected with the use of cultural practices such as bunch covering materials in ‘HLH Mauritius’ and ‘Wai Chee’. Beneficial effects on fruit size were obtained with thicker covering materials with nominal mass of 70 and 80 g/m² respectively on ‘HLH Mauritius’, while with ‘Wai Chee’, thinner covering materials (60 and 65 g/m²) showed enhancing effects. Maturation rate was significantly delayed only on ‘Wai Chee’ with the use of thicker covering materials (70 and 80 g/m²). Differences in colour were detected amongst different covering materials, but these should be verified with chromameter technology. Covering of fruit bunches for better fruit size and a later harvest date would, especially for ‘Wai Chee’ as a late season cultivar, be beneficial, since better prices are realised towards the end of the season. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

by Huanpu Jun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 122-136. / Acknowledgement --- p.iii / Abstract --- p.V / Introduction --- p.1 / Literatiure review --- p.3 / Chapter A. --- "The changes of fruit during development, maturation, senescence" --- p.3 / Chapter 1. --- Fruit --- p.3 / Chapter 2. --- Fruit cell --- p.6 / Chapter 3. --- Respiration and ethylene --- p.18 / Chapter 4. --- Other oxidative reaction --- p.21 / Chapter 5. --- Control of ripening --- p.22 / Chapter B. --- In period of harvest and storage --- p.23 / Chapter 1. --- After harvest --- p.24 / Chapter 2. --- Postharvest technology procedures --- p.25 / Chapter C. --- Litchi --- p.28 / Chapter 1. --- Morphology and embryology --- p.28 / Chapter 2. --- Composition --- p.30 / Material and methods --- p.33 / Chapter A. --- "Morphological , anatomical and physical studies" --- p.33 / Chapter B. --- Biochemi cal studiets --- p.34 / Chapter 1. --- Starch content --- p.34 / Chapter 2. --- Soluble protein content --- p.35 / Chapter 3. --- Sugar component separated by thin layer chromatography --- p.36 / Chapter 4. --- Reducing sugar content --- p.36 / Chapter 5. --- Total sugars --- p.37 / Chapter 6. --- Acid content --- p.37 / Chapter 7. --- Chlorophyll contents --- p.37 / Chapter 8. --- Anthocyanin contents --- p.38 / Chapter 9. --- Phenolic compound content --- p.33 / Chapter 10. --- Peroxidase activity --- p.39 / Chapter 11. --- Superoxide dismutase activity --- p.39 / Chapter 12. --- Vitamin C content --- p.40 / Chapter C. --- Preliminary study on storage --- p.41 / Results --- p.43 / Chapter A. --- Development period --- p.43 / Chapter 1. --- "Morphological , anatomical and physical changes" --- p.43 / Chapter i. --- Whole Fruit --- p.43 / Chapter ii. --- Seed --- p.43 / Chapter iii. --- Aril --- p.44 / Chapter 2. --- Rhysio1ogica1 and biochemical changes --- p.47 / Chapter i. --- Weight and water content --- p.47 / Chapter ii. --- Soluble protein content --- p.52 / Chapter iii. --- Starch content --- p.52 / Chapter iv. --- Acidity --- p.52 / Chapter v. --- Sugar content --- p.61 / Chapter vi. --- Change in pericarp --- p.68 / Chapter B. --- Storage period --- p.63 / Chapter 1. --- Fruit without any treatment stored at 5°C and 10°C --- p.63 / Chapter 2. --- Fruit was treated and packed with different methods and then stored at 10°C and room temperature respectively --- p.75 / Chapter i. --- Change in Fresh weight of stored Fruit --- p.75 / Chapter ii. --- Rate of rotting --- p.78 / Chapter iii. --- Rate of darkening --- p.78 / Chapter iv. --- Anthocyanin --- p.87 / Chapter v. --- Phenolic compound --- p.87 / Chapter vi. --- Chlorophyll --- p.88 / Chapter vii. --- Acidity --- p.88 / Chapter viii. --- Total sugar --- p.101 / Chapter ix. --- Reducing sugar --- p.101 / Chapter x. --- Ascorbic acid --- p.106 / Chapter xi. --- Peroxidase activity --- p.106 / Chapter xii. --- Superoxide dismutase --- p.107 / Discussion --- p.114 / Reference --- p.122

Thesis (MSc. (Horticulture)) -- University of Limpopo, 2019 / After harvesting litchi fruit, the red pericarp colour is rapidly lost resulting in discolouration and browning during storage and marketing. To mitigate this challenge, the South African litchi industry uses sulfur dioxide fumigation to retain litchi fruit red pericarp colour during extended storage and shelf-life. However, there are health concerns regarding the commercially used (SO2) fumigation for litchi pericarp colour retention due to high levels of SO2 residues in fruit aril. Therefore, this study aimed to explore the possibility of Uvasys slow release SO2 sheets to retain ‘Mauritius’ litchi fruit red pericarp colour when packaged in plastic-punnets and bags. Treatment factors were two packaging materials (plastic-punnets and bags), six SO2 treatments (control; SO2 fumigation and four SO2 sheets viz. Uva-Uno-29% Na2S2O5; Dual-Release-Blue35.85% Na2S2O5; Slow-Release-36.5% Na2S2O5 and Dual-Release-Green-37.55% Na2S2O5) and four shelf-life periods (day 0, 1, 3 and 5). ‘Mauritius’ fruit were assessed for pericarp Browning Index (BI), Hue angle (ho), Chroma (C*) and Lightness (L*). In this study, an interactive significant effect (P < 0.05) between packaging type and SO2 treatments was observed on ‘Mauritius’ fruit pericarp L*, C* and ho during shelf-life. Fruit stored in plastic-bags and treated with SO2 fumigation showed higher pericarp C* and L*, while SO2 fumigated fruit in plastic-punnets had higher pericarp ho. Lower pericarp BI was observed in SO2 fumigated fruit stored in plastic-bags, which showed less pericarp browning than fruit in other treatments. In general, commercial SO2 fumigation resulted in lower pericarp BI, and higher pericarp L*, C* and ho throughout the storage and shelf-life. Our correlation analyses results further showed that litchi fruit red pericarp colour was better preserved as SO2 treatment levels increased, especially in plastic-bags. In retaining ‘Mauritius’ litchi fruit red pericarp colour, Uvasys SO2 sheets were not effective when compared with commercial SO2 fumigation. However, commercially SO2 fumigated fruit were bleached throughout the storage and shelf-life. Furthermore, fruit from all treatments were spoiled due to decay and mould growth after day 5 of shelf-life. Inclusion of pathogen protectants is important in future research to demonstrate whether Uvasys SO2 sheet-packaging technology can retain ‘Mauritius’ litchi fruit pericarp colour. / Agricultural Research Council and National Research Foundation (NRF)

Made available in DSpace on 2015-03-26T13:39:56Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2229897 bytes, checksum: 70eb16f12cce914df8ee78e6c6f6ea23 (MD5) Previous issue date: 2013-03-11 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The aim of this study was to assess the influence of different times of the year and substrates on the rooting of air layers of lychee (Litchi chinensis Sonn.) for the production of seedlings to ensure the formation of uniform and productive orchards. Air layers were done in plants of the Bengal cultivar using leafy and healthy woody branches, with about 1.0 to 1.5 cm in diameter, in which complete girdling were performed with 2.0 cm wide at a distance of 30 to 40 cm below the apex. Then the branches were wrapped in moistened substrate. Air layering was made at six times of the year (January, March, May, July, September and November) and two substrates were used (coconut fiber and sphagnum) in a 6 x 2 factorial design in a randomized block with ten replicates, each block represented by a matrix plant. After 90 days, layers were separated from the matrix plant and evaluated for rooting and callus formation; root number, considering only the primary roots; length, area, volume and diameter of the roots; dry mass of roots and calluses, in addition to the dry mass of shoots (leaves and stems). The months of January, March, September and November showed the best results for allanalyzed variables related to rooting. With respect to the substrates, the only difference was in the months of January and March regarding root number and dry mass of roots, where the sphagnum showed the best results. The month of July was more favorable to the formation of calluses. The period between September and March was more suitable to the propagation of lychee, when there were rooting percentages above 90%, in addition to the formation of large amounts of roots. / Neste estudo, objetivou-se verificar a influência da época do ano e de diferentes substratos no enraizamento de alporques de lichieira (Litchi chinensis Sonn.), visando à produção de mudas que assegurem a formação de pomares uniformes e produtivos. Foram feitos alporques em plantas da cultivar Bengal, utilizando ramos lenhosos bem enfolhados e sadios, com cerca de 1,0 a 1,5 cm de diâmetro, nos quais foram realizados anelamentos completos de 2,0 cm de largura, à distância de 30 a 40 cm abaixo do seu ápice. Em seguida, os ramos foram envoltos por substrato umedecido. Foram avaliadas seis épocas de realização dos alporques (janeiro, março, maio, julho, setembro e novembro) e dois substratos (esfagno e fibra de coco), em um esquema fatorial 6 x 2, no delineamento em blocos casualizados com dez repetições, sendo cada bloco representado por uma planta-matriz. Passados 90 dias, os alporques foram separados da planta-matriz e avaliados quanto à porcentagem de enraizamento e de calejamento; ao número de raízes, considerando apenas as raízes primárias; ao comprimento, à área, ao volume e ao diâmetro das raízes; à massa seca de raízes e calos, além da massa seca da parte aérea (folhas e caule). Os melhores resultados para todas as variáveis relacionadas ao enraizamento analisadas foram verificados nos meses de janeiro, março, setembro e novembro. Com relação aos substratos, houve diferença apenas nos meses de janeiro e março para número de raízes e massa seca de raízes, tendo o esfagno apresentado os melhores resultados. O mês de julho foi mais propício à formação de calos. O período compreendido entre os meses de setembro e março foi o mais propício à propagação da lichieira, quando foram obtidas porcentagens de enraizamento superiores a 90%, além da formação de grande quantidade de raízes.

A espécie Litchi chinensis Sonn., popularmente conhecida como lichieira, é originária da China e tem aplicações medicinais em muitos países, em especial pela medicina tradicional chinesa. O objetivo deste trabalho foi avaliar química e biologicamente o extrato de folhas e frações desta espécie. Foi preparado o extrato hidroetanólico das folhas e, a partir da partição líquido-líquido, foram obtidas as frações hexânica, acetato de etila, butanólica e aquosa. Foi utilizada a técnica de espectrometria de massas ESI-IT-MSn para traçar o perfil do extrato e das frações. Procedeu-se à quantificação dos teores de fenóis totais, de flavonoides totais, do poder sequestrante do radical DPPH e do poder redutor do extrato de folhas e frações. Além disso, foram avaliadas também as seguintes atividades biológicas in vitro: antimicrobiana para bactérias e fungos (ensaio da difusão em ágar e concentração inibitória mínima), leishmanicida e citotoxicidade. O extrato de folhas e frações apresentaram compostos fenólicos como principais constituintes químicos, tais como flavonoides (agliconas e heterosídeos) e taninos condensados. Os resultados da determinação dos fenólicos totais e flavonoides demonstraram que existe uma maior concentração destes compostos na fração acetato de etila em relação ao extrato de folhas e às outras frações e a avaliação do poder sequestrante de radicais DPPH e do poder redutor demonstra que esta fração também apresentou maior atividade antioxidante in vitro em comparação ao extrato de folhas e às outras frações. Assim, evidencia-se a possível correlação entre estes compostos e a atividade antioxidante. O extrato de folhas de L. chinensis e frações testados neste trabalho apresentaram atividade antimicrobiana contra as seguintes bactérias gram-positivas: Bacillus subtilis, Bacillus cereus, Micrococcus luteus, Enterococcus faecalis, Staphylococcus aureus e frente à bactéria gram-negativa Proteus mirabilis. O extrato de folhas de L. chinensis e frações não apresentaram atividade contra L. amazonensis até a concentração testada de 40 µg/mL, nem tampouco apresentaram toxicidade aos macrófagos murinos até a concentração testada (160 µg/mL). A fração acetato de etila (FrAcOEt) do extrato de folhas apresentou os melhores resultados quanto ao teor de fenóis totais, flavonoides totais, a melhor atividade antioxidante e os menores valores de concentração inibitória mínima, evidenciando assim a viabilidade desta fração do extrato de folhas como fonte potencial de compostos bioativos. / The species Litchi chinensis Sonn., popularly known as litchi, originated in China and has medicinal applications in many countries, particularly in traditional chinese medicine. The aim of this study was to evaluate leaf extract and fractions of this species both chemically and biologically. The hydroethanolic leaf extract was prepared, and from the liquid-liquid partition, the fractions hexane, ethyl acetate, butanol and aqueous acetate were obtained. The technique of mass spectrometry ESI -IT-MSn was used to determine the profile the extract and fractions. The quantification of total phenolic content, total flavonoid, the scavenging power of DPPH radical and the reducing power of leaf extracts and fractions was carried out. In addition, the following in vitro biological activities were also evaluated: antimicrobial for bacteria and fungi (agar diffusion method and minimum inhibitory concentration), leishmanicidal and cytotoxicity. The leaf extract and fractions showed phenolic compounds as major chemical constituents, such as flavonoids (aglycones and glycosides) and condensed tannins. The results of the determination of total phenolics and flavonoids have shown that there is a higher concentration of these compounds in the ethyl acetate fraction compared to the leaf extract and other fractions and evaluation of scavenging power of DPPH radical and reducing power demonstrates that this fraction also showed higher antioxidant activity in vitro compared to the leaf extract and other fractions. Thus, there is evidence of a possible correlation between these compounds and antioxidant activity. The leaf extract of L. chinensis and fractions tested in this work had the following antimicrobial activity against gram-positive bacteria: Bacillus subtilis, Bacillus cereus, Micrococcus luteus, Enterococcus faecalis, and Staphylococcus aureus and against the gram-negative bacteria Proteus mirabilis. The leaf extract of L. chinensis and fractions showed no activity against L. amazonensis tested up to a concentration of 40 mg/mL, nor were toxic to murine macrophages in the concentration tested (160 mg/mL). The ethyl acetate fraction (FrAcOEt) of leaf extracts showed the best results on the content of total phenolics, total flavonoids, the best antioxidant activity and the lowest values of minimum inhibitory concentration, thus demonstrating the viability of this fraction of the leaf extract as a potential source of bioactive compounds.

Made available in DSpace on 2014-06-11T19:22:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-07Bitstream added on 2014-06-13T19:48:28Z : No. of bitstreams: 1 souza_av_me_botfca.pdf: 762205 bytes, checksum: 1a231de04b5d58772485080e2c088804 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Este trabalho teve como objetivo prolongar a vida útil de lichias cv. ‘Bengal’ sob refrigeração provenientes de Carlópolis - PR, com o emprego do tratamento térmico em frutos refrigerados. Os frutos foram submetidos aos tratamentos: Imersão dos frutos em água a 45°C por: T – 1: controle; T – 2: 5 minutos; T – 3: 10 minutos; T – 4: 15 minutos; T – 5: 20 minutos e T – 6: 25 minutos. Depois de higienizados com 150ppm de cloro e secos, os frutos foram acondicionados em bandejas de poliestireno expandido e embalados com filme de policloreto de vinila 0,020mm, com 10 frutos cada uma (cerca de 200 gramas) e armazenados em B.O.D. a 5ºC e 90±5% de UR por 15 dias. Os frutos foram analisados quanto à avaliação visual, perda de massa fresca, firmeza, potencial hidrogeniônico (pH), acidez titulável (AT), sólidos solúveis (SS), relação SS/AT (“Ratio”), ácido ascórbico, açúcares redutores, respiração, coloração, atividade específica da polifenol oxidase - PPO (EC. 1.14.18.1) e da peroxidase – POD (EC. 1.11.1.7) logo após a colheita e na retirada da B.O.D. aos 3, 6, 9, 12 e 15 dias. O delineamento estatístico empregado foi inteiramente casualizado com três repetições por tratamento para cada um dos seis tempos de avaliação, utilizando-se o Teste de Tukey a 5% de probabilidade. Nas condições experimentais, pode-se concluir que o tratamento térmico aos 5 ou a 10 minutos/45ºC mostraram-se mais eficazes na manutenção da coloração dos frutos que é o fator mais importante na qualidade dos frutos de lichia e não causou modificações na qualidade da sua polpa. / This research was realized aiming to prolong the shelf life of the ‘Bengal’ lychees under refrigeration, from the Carlópolis city, PR State, Brazil, with the use of thermal treatments in refrigerated fruits. The fruits were subjected to the treatments: immersion in water to 45°C by: T - 1: control; T – 2: 5 minutes; T – 3: 10 minutes; T – 4: 15 minutes; T – 5: 20 minutes and T – 6: 25 minutes. After cleaned with 150 ppm of chlorine and dried, the fruits were packed in polystyrene trays and wrapped with polyvinyl chloride film 0,020 mm, with 10 fruits in each one (about 200 grams) and stored in B.O.D. to 5°C and 90±5% of RU by 15 days. The fruits were analyzed concerning the visual evaluation, loss of weight mass, firmness, hydrogenionic potential (pH), titulable acidity (TA), soluble solids (SS), SS/TA relation (“Ratio”), ascorbic acid, reducing sugar, respiration, color, specific activity of the polyphenol oxidase – PPO (EC. 1.14.18.1) and peroxidase – POD (EC. 1.11.1.7) soon after the harvest and in the removal of the B.O.D. (in 3, 6, 9, 12 and 15 days).The statistical delineation used was completely randomized, with three replications by treatment for each one in the six times of evaluation, using the Tukey test to 5% of probability. In experimental conditions, can be conclude that the thermical treatments with 5 or 10 minutes/45°C showed more effective in maintaining the coloration of fruits, which is the most important factor in quality of the lychee fruits and did not cause changes in the quality of the pulp.