No description available.

PhD (Agriculture) / Department of Food Science

Thesis (PhD (Viticulture and Oenology. Wine Biotechnology))--Stellenbosch University, 2008. / Although bananas are widely grown worldwide in many tropical and a few subtropical countries, banana beverages are still among the fruit beverages processed by use of rudimentary methods such as the use of feet or/and spear grass to extract juice. Because banana juice and beer remained on a home made basis, there is a research drive to come up with modern technologies to more effectively process bananas and to make acceptable banana juices and wines. One of the main hindrances in the production of highly desirable beverages is the pectinaceous nature of the banana fruit, which makes juice extraction and clarification very difficult. Commercial enzyme applications seem to be the major way forward in solving processing problems in order to improve banana juice and wine quality. The particular pectinolytic enzymes that were selected for this study are Rapidase CB, Rapidase TF, Rapidase X-press and OE-Lallzyme. In addition this study, investigate the applicability of recombinant yeast strains with pectinolytic, xylanolytic, glucanolytic and amylolytic activities in degrading the banana polysaccharides (pectin, xylan, glucan starch) for juice and wine extraction and product clarification. The overall objective of this research was to improve banana juice and wine by enzymatic processing techniques and to improve alcoholic fermentation and to produce limpid and shelf-stable products of clarified juice and wine. The focus was on applying the selected commercial enzyme preparations specifically for the production of better clarified banana juice and wine. This is because the turbid banana juice and beer, which contain suspended solids that are characterised by a very intense banana flavour, require a holistic approach to address challenges and opportunities in order to process pure banana beverages with desirable organoleptic qualities. The specific objectives of applying commercial enzymes in the processing of banana juice and wine, comparing with grape winemaking practices, use of recombinant yeast and analyses of various parameters in the juices and wines made have enabled generation of information that could be of help to prospective banana juice and wine processors. The research findings obtained could be used to establish a pilot plant or small-scale industry in the banana processing beverages producing large quantities,and finally the overall objective of obtaining limpid and shelf stable products would be achieved.

Ho, Sai Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 144-164). / Abstracts in English and Chinese. / TABLE OF CONTENTS --- p.ii / ABSTRACT --- p.xii / 撮要 --- p.xv / LIST OF ABBREIVIATIONS --- p.xvi / LIST OF TABLES --- p.xvii / LIST OF FIGURES --- p.xix / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Overview of lectins --- p.1 / Chapter 1.1.1 --- History of lectins --- p.1 / Chapter 1.1.2 --- Definitions of lectins --- p.2 / Chapter 1.1.3 --- Classification and nomenclature of lectins based on structure --- p.2 / Chapter 1.1.4 --- Classification and nomenclature of lectins based on carbohydrate-bindingspecificity --- p.4 / Chapter 1.1.5 --- Structure of plant lectins --- p.4 / Chapter 1.1.6 --- Biological function of plant lectins --- p.5 / Chapter 1.1.6.1 --- Anti-viral activity of plant lectiins --- p.5 / Chapter 1.1.6.2 --- Lectins as plant defense proteins --- p.6 / Chapter 1.1.6.3 --- Insecticidal activity of plant lectins --- p.7 / Chapter 1.1.6.4 --- Anti-fungal activity of plant lectins --- p.7 / Chapter 1.1.6.5 --- Mitogenic activity of plant lectins --- p.7 / Chapter 1.1.6.6 --- Anti-tumor and anti-proliferative activity of plant lectins --- p.9 / Chapter 1.1.7 --- Background of legume lectins --- p.11 / Chapter 1.1.7.1 --- Structure of legume lectins --- p.11 / Chapter 1.1.7.2 --- Functions and activities of legume lectins --- p.12 / Chapter 1.2 --- Overview of serine protease inhibitors in plants --- p.14 / Chapter 1.2.1 --- Classification of serine protease inhibitor --- p.15 / Chapter 1.2.2 --- The main functions of plant serine protease inhibitors --- p.17 / Chapter 1.2.3 --- Commercial application of serine protease inhibirtors --- p.19 / Chapter 1.2.3.1 --- Medical application --- p.19 / Chapter 1.2.3.2 --- Transgenic application in agriculture --- p.22 / Chapter 1.3 --- Overview of Pathogenesis-related proteins in plants --- p.25 / Chapter 1.3.1 --- Overview of PR-5 family Thaumatin-like proteins (TLPs) --- p.27 / Chapter 1.3.1.1 --- Structural similarities among TLPs --- p.28 / Chapter 1.3.1.2 --- Antifungal activity of TLP --- p.31 / Chapter 1.3.2 --- Overview of Chinase-like proteins (CLPs) --- p.33 / Chapter 1.3.2.1 --- Classification of chitinase --- p.34 / Chapter 1.3.2.1.1 --- On the basis of amino acid sequence of glycosyl hydrolase --- p.34 / Chapter 1.3.2.1.2 --- On the basis of amino acid sequence of plant chitinase --- p.35 / Chapter 1.3.2.2 --- Antifungal activity of CLP --- p.36 / Chapter 1.3.3 --- Anti-freeze property of PR proteins --- p.38 / Chapter 1.3.4 --- Application of PR proteins in agriculture --- p.40 / Chapter 1.4 --- Rationale of the present study --- p.42 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- Materials --- p.43 / Chapter 2.2 --- Preparation of crude extract --- p.44 / Chapter 2.2.1 --- Hokkaido large black soybean --- p.44 / Chapter 2.2.2 --- Emperor banana --- p.45 / Chapter 2.3 --- Purification --- p.45 / Chapter 2.4 --- Chromatography --- p.46 / Chapter 2.4.1 --- DEAE-cellulose chromatography --- p.46 / Chapter 2.4.2 --- Affi-gel Blue gel --- p.47 / Chapter 2.4.3 --- SP-Sepharse --- p.48 / Chapter 2.4.4 --- Mono Q HR 5/5 and Mono S HR 5/5 --- p.49 / Chapter 2.4.5 --- Superdex 75 and superdex 200 --- p.50 / Chapter 2.5 --- Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) --- p.50 / Chapter 2.6 --- Protein concentration determination --- p.54 / Chapter 2.7 --- Preparation of rabbit reticulocyte lysate --- p.54 / Chapter 2.8 --- Determination of N-terminal amino acid sequence --- p.56 / Chapter 2.9 --- Assay of inhibition of hemagglutinating activity by different carbohydrates --- p.56 / Chapter 2.10 --- Thermal stability determination assays --- p.57 / Chapter 2.10.1 --- Stability at various temperatures --- p.57 / Chapter 2.10.2 --- Stability at 100°C --- p.57 / Chapter 2.11 --- Assay of pH dependence of hemagglutinating activity --- p.58 / Chapter 2.12 --- Assay of ion dependence of hemagglutinating activity --- p.58 / Chapter 2.13 --- Assay of antifungal activity --- p.58 / Chapter 2.14 --- Assay of trypsin inhibitory activity --- p.60 / Chapter 2.15 --- Assay of antibacterial activity --- p.61 / Chapter 2.16 --- Assay for cytotoxic activity on cancer cell lines --- p.61 / Chapter 2.17 --- Assay for HIV-1 reverse transcriptase (RT) inhibitory activity --- p.62 / Chapter 2.18 --- Assay of mitogenic activity --- p.63 / Chapter Chapter 3 --- Purification and Characterization of Defense-Related Proteins from their Respective Sources / Chapter 3.1 --- Purification and Characterization of a Lectin from the Seeds of Hokkaido large black soybean / Chapter 3.1.1 --- Introduction --- p.65 / Chapter 3.1.2 --- Results --- p.66 / Chapter 3.1.3 --- Purification --- p.68 / Chapter 3.1.3.1 --- Affinity chromatography on Affi-gel Blue gel --- p.69 / Chapter 3.1.3.2 --- Anion-exchange chromatography on DEAE-cellulose --- p.70 / Chapter 3.1.3.3 --- Anion-exchange chromatography on Mono Q column --- p.71 / Chapter 3.1.3.4 --- Gel filtration on Superdex 200 column --- p.72 / Chapter 3.1.3.5 --- Hemagglutinating activity at each purification step --- p.73 / Chapter 3.1.4 --- Characterization of Lectin --- p.74 / Chapter 3.1.4.1 --- Molecular mass determination --- p.74 / Chapter 3.1.4.2 --- N-terminal amino acid sequencing --- p.76 / Chapter 3.1.4.3 --- Assay of inhibition of hemagglutinating activity by different carbohydrates --- p.77 / Chapter 3.1.4.4 --- Thermal stability --- p.78 / Chapter 3.1.4.5 --- Assay of pH dependence of hemagglutinating activity --- p.80 / Chapter 3.1.4.6 --- Assay of ion dependence of hemagglutinating activity --- p.81 / Chapter 3.1.4.7 --- Assay for HIV-1 reverse transcriptase (RT) inhibitory activity --- p.82 / Chapter 3.1.4.8 --- Assay of mitogenic activity --- p.83 / Chapter 3.1.4.9 --- Assay of antibacterial activity --- p.84 / Chapter 3.1.5 --- Discussion --- p.86 / Chapter 3.2 --- Purification and Characterization of a Trypsin inhibitor from the Seeds of Hokkaido large black soybean / Chapter 3.2.1 --- Introduction --- p.93 / Chapter 3.2.2 --- Results --- p.94 / Chapter 3.2.3 --- Purification --- p.95 / Chapter 3.2.3.1 --- Anion-exchange chromatography on Mono Q column --- p.96 / Chapter 3.2.3.2 --- Gel filtration on Superdex 75 column --- p.98 / Chapter 3.2.3.3 --- Trypsin inhibitory activity at each purification step --- p.99 / Chapter 3.2.4 --- Characterization of trypsin inhibitory --- p.100 / Chapter 3.2.4.1 --- Molecular mass determination --- p.100 / Chapter 3.2.4.2 --- N-terminal amino acid sequencing --- p.102 / Chapter 3.2.4.3 --- Assay for HIV-1 reverse transcriptase (RT) inhibitory activity --- p.103 / Chapter 3.2.4.4 --- Antiproliferative effect on MCF-7 and Hep G2 cells --- p.104 / Chapter 3.2.4.5 --- pH and thermal stability --- p.105 / Chapter 3.2.5 --- Discussion --- p.106 / Chapter 3.3 --- Purification and Characterization of a Thaumatin-like protein and Chitinase-like protein from Emperor Banana / Chapter 3.3.1 --- Introduction --- p.108 / Chapter 3.3.2 --- Results --- p.109 / Chapter 3.3.3 --- Purification --- p.111 / Chapter 3.3.3.1 --- Affinity chromatography on Affi-gel Blue gel --- p.112 / Chapter 3.3.3.2 --- Cation exchange chromatography on Mono S column --- p.113 / Chapter 3.3.3.3 --- Gel filtration on Superdex 75 column --- p.114 / Chapter 3.3.3.3.1 --- Fraction MS 2 --- p.114 / Chapter 3.3.3.3.2 --- Fraction MS 4 --- p.115 / Chapter 3.3.3.3.3 --- Fraction MS 5 --- p.118 / Chapter 3.3.4 --- Characterization of the thaumatin-like protein --- p.121 / Chapter 3.3.4.1 --- N-terminal amino acid sequence determination --- p.121 / Chapter 3.3.4.2 --- Assay for antifungal activity --- p.122 / Chapter 3.3.4.3 --- Thermal stability --- p.124 / Chapter 3.3.4.4 --- pH stability --- p.125 / Chapter 3.3.4.5 --- Resistance to trypsin digestion --- p.125 / Chapter 3.3.4.6 --- Anti-HIV-1 reverse transcriptase activity --- p.126 / Chapter 3.3.4.7 --- Discussion --- p.127 / Chapter 3.3.5 --- Characterization of the two chitinase-like protein --- p.131 / Chapter 3.3.5.1 --- N-terminal amino acid sequence determination --- p.131 / Chapter 3.3.5.1.1 --- Emperor banana MS2 CLP --- p.131 / Chapter 3.3.5.1.2 --- Emperor banana MS4 CLP --- p.132 / Chapter 3.3.5.2 --- Assay for antifungal activity --- p.133 / Chapter 3.3.5.3 --- Discussion --- p.136 / Chapter Chapter 4 --- general discussion --- p.138 / References --- p.144

No description available.

In the genus Fusarium are many important plant pathogens. The diversity of hosts the genus attacks, the number of pathogenic taxa and the range of habitats in which they cause disease are the greatest in plant pathology. One important species complex within the genus Fusarium is Fusarium oxysporum Schlecht. This species complex consists more than 80 pathogenic forma specialis and is particularly difficult to control. The fungi can survive in soil for decades as specialized spores, known as chlamydospores. Interestingly, however, this species complex also contains beneficial non-pathogenic forms that can be exploited to manage Fusarium wilt diseases. In this study, the ability of non-pathogenic F. oxysporum strains, Trichoderma harzianum Rifai Eco-T®, soluble silicon, and their combination was evaluated on two important crops, banana (Musa sp. L.) and beans (Phaseolus vulgaris L.), for their potential to suppress pathogenic strains of F. oxysporum. The ability of these crops to take up and accumulate silicon in their organs, and its effect on low temperature stress was also investigated. Several endophytic fungi, mainly Fusarium spp. and bacteria, were isolated from healthy mature banana plants. After preliminary and secondary in vivo screening tests against F. oxysporum f.sp. phaseoli on beans (Phaseolus vulgaris L.) cv. Outeniqua, two non-pathogenic F. oxysporum strains were selected for further testing. These two non-pathogenic F. oxysporum strains were found to colonize banana (Musa sp.) cv. Cavendish Williams and bean plants, and to suppress Fusarium wilt of these crops. In order to improve the efficacy of these biocontrol fungi, soluble silicon was introduced. The relationship between plant mineral nutrition and plant diseases have been reported by several authors. Plants take up silicon equivalent to some macronutrients, although it is not widely recognized as an essential element. In this study, we established that roots, the target plant organ for soilborne plant pathogens, accumulated the greatest quantity of silicon of any plant organs when fertilized with high concentrations of silicon. On the other hand, the corm and stem accumulated the least silicon. Such observations contradict the concept of passive uptake of silicon via the transpiration stream in these plants as the only uptake mechanism. The prophylactic properties of silicon have been documented for many crops against a variety of diseases. In vitro bioassay tests of silicon against these wilt pathogens showed that silicon can be toxic to Fusarium wilt fungi at high concentrations (>7840 mg .-1), resulting in complete inhibition of hyphal growth, spore germination and sporulation. However, low concentrations of silicon (<490 mg .-1) encouraged hyphal growth. Silicon fertilization of banana and beans significantly reduced disease severity of these crops by reducing the impact of the Fusarium wilt pathogens on these crops. However, it could not prevent infection of plants from the wilt pathogens on its own. Synergistic responses were obtained from combined applications of silicon and non-pathogenic F. oxysporum strains against Fusarium wilt of banana. Combinations of silicon with the non-pathogenic F. oxysporum strains significantly suppressed disease severity of Fusarium wilt of banana, caused by F. oxysporum f.sp. cubense (E.F. Smith) Snyder & Hansen, better than applications of either control measure on their own. Banana production in the subtropical regions frequently suffer from chilling injury, and from extreme variations between night and day temperatures. Such stress predisposes banana plants to Fusarium wilt disease. Silicon, on the other hand, is emerging as important mineral in the physiology of many plants, ameliorating a variety of biotic and abiotic stress factors. We established that silicon fertilization of banana plants significantly reduced chilling injury of banana plants. Membrane permeability, lipid peroxidation (MDA level) and proline levels were higher in silicon-untreated plants than the treated ones, all of which demonstrated the stress alleviating effect of silicon. Low temperatures damage the cell membrane of susceptible plants and cause desiccation or dehydration of these cells. Levels of sucrose and raffinose, recognized as cryoprotectants, were significantly higher in silicon-amended banana plants than unamended plants. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

PhD (Agric) / Department of Food Science

La certificación de Comercio Justo ha transformado el comercio convencional e impactado en la forma de trabajar de agricultores, exportadores y trabajadores dedicados al sector agroalimentario. La creciente demanda de productos sostenibles ha impulsado una mayor cantidad de productos certificados, entre ellos el banano. A pesar de que, este movimiento enfocado en los seres humanos y la sostenibilidad social, económica y medio ambiental de las sociedades no es un modelo comercial nuevo, aún existen personas que no tienen conocimiento de la existencia de los productos certificados por el Comercio Justo ni la labor que cumple mediante sus reglas establecidas. El objetivo del presente estudio es analizar el efecto del Comercio Justo en las exportaciones de bananos orgánicos producidos en Piura hacia Países Bajos durante el periodo 2013-2018, haciendo énfasis principalmente en 3 principios que deben cumplir las empresas exportadoras y asociaciones si desean comercializar sus productos con el sello de certificación, los cuales son creación de oportunidades para productores desfavorecidos, precio justo y respeto por el medio ambiente. La metodología de la investigación es de enfoque mixto. La información cuantitativa se analizó a través del modelo, en tanto que, para el desarrollo cualitativo se realizó entrevistas semi estructuradas a exportadores del sector. A partir, de la discusión de resultados del desarrollo cuantitativo y cualitativo se concluyó que la creación de oportunidades y el respeto por el medio ambiente tuvieron un efecto positivo en las exportaciones de banano orgánico de Piura hacia Países Bajos durante el periodo 2013-2018. / Fairtrade certification has transformed conventional trade and impacted the way of working of farmers, exporters and workers dedicated to the agri-food sector. The growing demand for sustainable products has fueled a greater number of certified products, including bananas. Despite the fact that this movement that focuses on human beings and the social, economic and environmental sustainability of societies is not a new business model, there are still people who are unaware of either the existence of Fair-Trade certified products or the work that it fulfills through its established rules. The objective of this study is to analyze the effect of Fairtrade on the exports of organic bananas produced in Piura to the Netherlands during the period 2013-2018, mainly emphasizing 3 principles that exporting companies must comply with and associations if they want to have the certification seal on their products, which are creating opportunities for disadvantaged producers, fair prices and respect for the environment. The research methodology follows a mixed method design. Quantitative data was analyzed through the gravitational model and for the qualitative development, semi-structured interviews were carried out with exporters in the. From the discussion of quantitative and qualitative development results, it was concluded that create opportunities and respect for the environment had a positive effects on organic banana exports from Piura to the Netherlands during the period 2013-2018. / Tesis