Call number: LD2668 .T4 1985 M375 / Master of Science

Call number: LD2668 .T4 1985 V36 / Master of Science

M. Tech. Agriculture / Leafy vegetables, Swiss chard (Beta vulgaris L. var. cicla), lettuce (Lactuca sativa L.) and mustard spinach (Brassica juncea), are widely grown in South Africa. These leafy vegetables are popular owing to their availability and nutritional properties. Optimisation of crop nutrition is essential to maximize yield and quality of vegetables. Therefore, a study was conducted to evaluate the effect of different levels of nitrogen application on growth and quality parameters of leafy vegetables when grown in a non-circulating hydroponic system. The objective of this study is two-fold: primarily, to determine the influence of nitrogen on growth, yield and overall quality of Swiss chard, lettuce and mustard spinach grown in a non-circulating hydroponic system, and secondly, to determine the effect of nitrogen applications on bioactive compounds and antioxidants, such as antioxidant scavenging activities, ascorbic acid, total phenolics and flavonoids.

There is demand for improved security of refrigerated ready-to-eat meats. Antimicrobial edible films and coatings could function as an added barrier against post-processing contamination. Hops and hop extracts are known for their antimicrobial efficacy which is attributed to key antimicrobial components including humulones, lupulones, xanthohumol and various terpenoids. Yet, hop ethanol extract has not been studied as an antimicrobial to incorporate into edible protein films and/or coatings. The overall objective of this research was to evaluate hop ethanol extract as an antimicrobial agent incorporated into edible soy protein isolate (SPI) films and coatings, and the influence on the shelf-life and sensory attributes of bologna. Hop ethanol extract was examined for minimum inhibitory concentration before the extract was incorporated into a 6% SPI solution at 0, 10, and 20% levels to determine antimicrobial efficacy as a cast film and simulated coating via zone of inhibition against Listeria monocytogenes strains ATCC 4644, UKADL and ATCC 49594. The results showed that hop ethanol extract alone was inhibitory of all three strains. Moreover, the hop ethanol extract, when incorporated at 10 and 20% (v/v) into edible soy protein isolate (SPI) films and simulated coatings, exhibited antimicrobial action against all three L. monocytogenes strains. Key antimicrobial components, as mentioned above, were identified in the hop ethanol extract via mass spectrometry. The SPI with 10% incorporated hop ethanol extract (SPI+10%hop) antimicrobial coating was applied to bologna, prepared in lab without L. monocytogenes inhibitors, where it exhibited a significant (P ≤ 0.05) bacteriostatic effect against strain ATCC 4644. The SPI+10% hop coating was then applied to a commercial bologna to examine effects on shelf-life and sensory attributes. Significant differences (P ≤ 0.05) were found in instrumental red and yellow colors, however not in sensory color. There was no significant difference (P > 0.05) found in measured lipid oxidation between the bologna with no coating, SPI coating or SPI+10%hop coating. The incorporation of hop did exhibit a slightly bitter taste. Overall, these findings indicate that the SPI+10%hop antimicrobial coating functioned as an inhibitor of L. monocytogenes while producing minimal effects on shelf-life and sensory attributes of bologna.

Replacing meat from animals with cultured meat and edible insects might reduce the impact on climate and the environment. That said, in order to fulfill their function as a sustainable food, insects and cultured meat would need to be consumed, on a wider scale and with a real-time reduction in meat consumption.   The aim of this study was to explore consumers' attitudes toward consuming insects and cultured meat, whilst gathering an understanding of what consumers, themselves, believe to be acceptable to consume in the future. Fifteen individual semi-structured interviews, of both men and women, were conducted outside a supermarket in central Sweden. Data was transcribed and analyzed thematically. The results highlight that for some respondents, insects are perceived as alien and undesirable, while cultured meat was perceived as too unnatural to be eaten; whilst others expressed both reluctance and a curiosity towards cultured meat and edible insects. Most respondents believed they will eat less meat, more vegetables and vegetarian protein in the future, and might try insects and cultured meat in hidden forms such as in sausage. The conclusion was that consumers had a mixed attitude toward eating insects and cultured meat. / Enligt FN och FAO måste matvanorna i västvärlden ändras eftersom de inte är hållbara. Jordbruket orsakar utsläpp av stora mängder växthusgaser, och köttproduktionen står för den allra största delen av dessa. Ätbara insekter och odlat kött kan vara alternativa proteinkällor till exempelvis kött, de är mer miljövänliga med avseende på koldioxidutsläpp, vattenförbrukning, markanvändning och energiåtgång. För att livsmedlen ska fylla sin funktion som hållbara proteinkällor så krävs det att de konsumeras av befolkningen. Syftet med denna studie var att studera svenska konsumenters attityder till att äta insekter och odlat kött, samt att undersöka vad konsumenterna själva tror att de kommer att äta i framtiden.   Studien är kvalitativ med en fenomenologisk ansats. Data insamlades med hjälp av intervjuer. 15 personer i olika åldrar deltog i studien, varav 8 kvinnor och 7 män.   Resultatet visade att det finns en blandad attityd till att äta insekter och odlat kött. Insekter upplevdes som främmande och äckligt, och odlat kött som alltför onaturligt för att ätas. Det fanns både en tveksamhet och en nyfikenhet hos respondenterna till dessa alternativa proteinkällor. Hos de som hade en positiv attityd till att äta livsmedlen uppgavs miljövinsterna som främsta anledning till att konsumera dem. Hos de som hade en negativ attityd angavs känslor av äckel som främsta anledning till att inte konsumera insekter och odlat kött. Om insekterna eller det odlade köttet var dolt såsom i korv kunde vissa respondenter tänka sig att äta. Faktorer som ett fördelaktigt pris, god tillgänglighet och att produkter baserade på odlat kött och insekter är godkända enligt livsmedelslagstiftning, påverkade respondenternas villighet att konsumera dessa. Respondenterna trodde framförallt att de kommer att äta mindre kött, mer grönsaker och mer vegetariskt protein i framtiden.   Slutsatsen är att det finns både positiva och negativa attityder till att äta insekter och odlat kött. Viljan att konsumera produkter baserade på dessa livsmedel verkar öka om livsmedlet är dolt, såsom i korv. Detta gäller både för insekter och odlat kött.

O presente trabalho teve como objetivos principais utilizar reações enzimáticas para a degradação de resíduos de laboratório e na síntese de álcoois quirais. Na primeira parte foi realizada uma triagem de microrganismos e enzimas hidrolíticas, objetivando a biorreciclagem de hexano presente no resíduo contendo uma mistura hexano-acetato de etila. Esta mistura é largamente utilizada para purificação de compostos químicos por cromatografia líquida. O método de biorreciclagem consistiu na hidrólise enzimática do acetato de etila, viabilizando, dessa forma, a recuperação do hexano puro de forma simples e rápida, pois os produtos dessa reação são altamente solúveis na fase aquosa. Na segunda parte do trabalho, avaliamos o potencial catalítico de diversas plantas comestíveis em reações orgânicas de óxido-redução visando à síntese enantiosseletiva de álcoois quirais. As reações escolhidas, para tal propósito, foram a redução de cetonas pró-quirais e a resolução cinética de álcoois via oxidação enantiosseletiva. Em muitos casos, os enantiômeros foram obtidos, separadamente, com pureza enantiomérica de até 99% dependendo da planta utilizada como biocatalizador. / The present work had as main goals the use of enzymatic reactions to degrade laboratory residues and to synthesize chiral alcohols. In the first part, it was carried out a screening of microorganisms and hydrolytic enzymes aiming the biorecycling of hexane from laboratory residues (a mixture of hexane-ethyl acetate). This misture is widely employed to purify chemicals by liquid chromatography. The biorecycling consists of enzymatic hydrolysis of ethyl acetate in a biphasic system. Due to the high solubility of the undesired products from this reaction in the aqueous phase, the hexane was easily recovered. To evaluate the possibility of treatment of effluents in a high amount, we carried out the biorecycling in a continuous system with tubular reactor using immobilized lipase (Novozyme 435). By the use of this system, the hydrolysis ratio was around 70% with no lost of enzyme stability along 6 hours work. In the second part of the work, we evaluated the catalytic potential of several edible plants in oxido-reduction reactions aiming the enantioselective synthesis of chiral alcohols. The chosen reactions were the reduction of prochiral ketones and the kinetic resolution by enantioselective oxidation. In several cases, depending of the plant employed as biocatalyst, the (R) or (S)- enantiomer were obtained in high enantiomeric purity (up to 99%). For example, the Arracacia xanthorrhiza B. (mandioquinha) performed an efficient enantioseletive reduction of 1-(4-bromophenyl)ethanone to the (S)-1-(4-bromophenyl)ethanol with 98% e.e. (enantiomeric excess), while the a Manihot esculenta (mandioca) gave the (R)-1-(4-bromophenyl)ethanol with 90% e.e. Some plants showed a good oxidative performance. For example, Coriandrum sativum L. (coentro) gave the quantitative oxidation of 1-(4-methyphenyl)ethanol to the 1-(4-metilphenyl)ethanona.

O mamão (Carica papaya L.) é um fruto nativo de clima tropical e comercializado em todo o mundo. O Brasil é um dos grandes produtores e consumidores destes frutos, porém, anualmente, são perdidas aproximadamente 10 toneladas dos frutos devido ao escasso controle de qualidade e, principalmente, às doenças pós-colheita, como a antracnose, ocasionada pelo fungo Colletotrichum gloeosporioides. O objetivo do presente estudo foi avaliar a associação de óleo essencial e película de carboximetilcelulose a fim de controlar a antracnose em mamão e monitorar os efeitos deste tratamento nas características físico-químicas e de aparência dos frutos. A pesquisa foi realizada em duas etapas: a primeira com caráter fitopatológico, e a segunda, quanto à qualidade físico-química e de aparência dos frutos tratados. Na primeira etapa foram realizados os seguintes testes: eficiência in vitro da Concentração Inibitória Mínima (CIM) dos óleos de Eucaliptus staigeriana, Lippia sidoides e Pimenta pseudocaryophyllus e suas misturas sobre o fungo C. gloeosporioides pelos métodos de diluição em ágar e modelo matemático de Gompertz; avaliação do óleo selecionado (o que apresentou a menor CIM), em relação à composição química; Concentração Mínima Fungicida (CMF) e eficiência in vivo (determinação da incidência e severidade). Na segunda etapa, foram avaliadas as qualidades físico-químicas (cor, perda de massa, firmeza, taxa respiratória, acidez titulável, teor de sólidos solúveis e ratio) e de aparência (presença de murchamento e podridão) nos frutos após a aplicação do óleo essencial associado à película. Na primeira etapa, os óleos essenciais de L. sidoides, E. staigeriana, P. pseudocaryophyllus e suas misturas apresentaram ação inibitória nos experimentos in vitro contra C. gloeosporioides. O melhor desempenho foi do óleo de L. sidoides, que apresentou concentração inibitória mínima de 125 ppm no método de diluição em ágar, e 75,3 ppm pelo modelo matemático de Gompertz. A concentração fungicida mínima encontrada foi 62 ppm pelo método de caldo. Quanto à composição de L. sidoides, o timol, que possui ação antifúngica reconhecida, foi encontrado como composto majoritário. Os resultados da avaliação in vivo mostraram que os menores valores de severidade ocasionada por C. gloesporiodes foram observadas no tratamento envolvendo a associação da película de carboximetilcelulose com o óleo essencial de L. sidoides, quando aplicados preventivamente, porém não inibiu a incidência da doença. Na segunda etapa do estudo, os resultados demonstraram que a utilização da película de carboximetilcelulose em associação com o óleo essencial de L. sidoides (375 ppm) conservou por 9 dias as características físico-químicas e de aparência dos mamões, enquanto que no controle e no tratamento somente com a película, 5 e 7 dias, respectivamente. Com base nos dados obtidos, concluiu-se que os óleos essenciais de Lippia sidoides, Eucaliptus staigeriana e Pimenta pseudocaryophyllus e suas misturas binárias 1:1 possuíram ação antifúngica contra C. gloeosporioides. Lippia sidoides demonstrou ser altamente eficaz em menor dose, e que a associação deste óleo (375 ppm) com a película de carboximetilcelulose (0,25%) contribuiu efetivamente para o aumento da vida útil dos mamões armazenados a 22°C, conservando suas características físico-químicas e de aparência por 9 dias. / The papaya (Carica papaya L.) is a tropical fruit and it is commercialized around the world. Brazil is one of the major producers and consumers of these fruits, but approximately 10 tons of fruits are lost annually due to poor quality control and especially postharvest diseases such as anthracnose, caused by Colletotrichum gloeosporioides fungus. The objective of the present study was to evaluate the association of essential oil and carboxymethylcellulose film in order to control the anthracnose in papaya and to monitor the effects of this treatment on its physicochemical and appearance characteristics. The research had two stages: the first one had phytopathological character and the second one regarding the physicochemical quality and appearance of treated fruits. In the first stage, the following tests were carried out: Determination in vitro of Minimum Inhibitory Concentration (MIC) for the Eucalyptus staigeriana, Lippia sidoides and Pimenta pseudocaryophyllus oils and their mixtures on C. gloeosporioides fungus by agar dilution and Gompertz mathematical model; Evaluation for the selected oil (the oil presenting the lowest MIC), of its chemical composition; Minimum Fungicidal Concentration (MFC) and in vivo efficiency (by incidence and severity determination). In the second stage it was evaluate the physicochemical qualities (color, weight loss, firmness, respiratory rate, titratable acidity, soluble solids content and ratio) and appearance (presence of shriveling and rot) of fruits after oil application associated with film. In the first stage, the essential oils of L. sidoides, E. staigeriana, P. pseudocaryophyllus and their mixtures showed inhibitory action in the in vitro experiments on C. gloeosporioides. The best oil was L. sidoides, it had a minimum inhibitory concentration of 125 ppm by agar dilution method and of 75.3 ppm by Gompertz mathematical model. The minimum fungicide concentration found was 62 ppm by the both method. About the composition of the L. sidoides oil, thymol, which has been reported as presenting antifungal activity, was found as its major compound. The results of in vivo evaluation showed that the lowest values of disease severity caused by C. gloesporiodes were present in the treatment involving the association of carboxymethylcellulose film with L. sidoides, when it was applied preventively, but it did not inhibit disease incidence. In the second stage of the study the results showed that the use of carboxymethylcellulose film in association with L. sidoides (375 ppm) preserved the physicochemical and appearance characteristics of papaya fruits for 9 days, whereas in the control and treatment with the film sole, it preserved for 5 and 7 days, respectively. Based on the obtained data, it was concluded that the essential oils of Lippia sidoides, Eucalyptus staigeriana and Pimenta pseudocaryophyllus and their 1:1 binary mixtures had antifungal action on C. gloeosporioides. Lippia sidoides, which proved to be highly effective, was more prominent, and the association of this oil (375 ppm) with the carboxymethylcellulose film (0,25%) effectively contributed to increased lifespan of stored papayas at 22°C, preserving its physicochemical and appearance characteristics for 9 days.

by Cheung Pui Yi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 124-135). / Abstract --- p.ii / Acknowledgements --- p.iv / List of Tables --- p.viii / List of Figures --- p.ix / List of Abbreviations --- p.xiii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- General Background --- p.1 / Chapter 1.2 --- Occurrence and Structure of Cellulose --- p.1 / Chapter 1.3 --- Occurrence and Structure of Hemicelluloses --- p.4 / Chapter 1.4 --- Biodegradation of Cellulose and Hemicelluloses --- p.4 / Chapter 1.4.1 --- Cellulolytic and Hemicellulolytic Microorganisms --- p.4 / Chapter 1.4.2 --- Enzymes Involved in Cellulose Degradation --- p.10 / Chapter 1.4.2.1 --- "Endo-1,4-β-glucanases" --- p.12 / Chapter 1.4.2.2 --- "Exo-1,4-β-glucanases" --- p.14 / Chapter 1.4.2.3 --- β-Glucosidases --- p.16 / Chapter 1.4.2.4 --- Oxidative Enzymes --- p.18 / Chapter 1.4.3 --- Synergistic Action between Cellulolytic Enzymes --- p.19 / Chapter 1.4.4 --- Enzymes Involved in Hemicellulose Degradation --- p.21 / Chapter 1.4.4.1 --- "Endo-1,4-β-xylanases" --- p.22 / Chapter 1.4.4.2 --- β-Xylosidases --- p.24 / Chapter 1.4.4.3 --- Other Xylanolytic Enzymes --- p.24 / Chapter 1.4.5 --- Synergistic Action between Hemicellulolytic Enzymes --- p.25 / Chapter 1.5 --- Flammulina velutipes --- p.26 / Chapter 1.6 --- Aims of the Present Investigation --- p.27 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- Organism --- p.28 / Chapter 2.2 --- Culture Medium --- p.28 / Chapter 2.3 --- Determination of the Optimal Growth pH of Flammulina velutipes --- p.29 / Chapter 2.4 --- "Preparation of Inoculum, Cultivation and Harvest of Fungal Cultures" --- p.30 / Chapter 2.5 --- Enzyme Assays --- p.30 / Chapter 2.5.1 --- "Exo-1,4-β-glucanase" --- p.30 / Chapter 2.5.2 --- "Endo-1,4-β-glucanase" --- p.31 / Chapter 2.5.3 --- "Endo-1,4-β-xylanase" --- p.34 / Chapter 2.5.4 --- Extracellular β-Glucosidase --- p.36 / Chapter 2.5.5 --- Cell-Associated β-Glucosidase --- p.38 / Chapter 2.5.6 --- Extracellular β-Xylosidase --- p.38 / Chapter 2.5.7 --- Cell-Associated β-Xylosidase --- p.38 / Chapter 2.6 --- Determination of Optimal Temperatures for Cellulolytic and Xylanolytic Enzymes --- p.39 / Chapter 2.7 --- Determination of the Optimal pH for Enzyme Reaction --- p.39 / Chapter 2.8 --- Protein Determination --- p.39 / Chapter 2.9 --- Determination of Enzyme Induction Patterns --- p.42 / Chapter 2.10 --- Elucidation of Cellulase Production Patterns in F. velutipes --- p.43 / Chapter 2.10.1 --- Native Polyacrylamide Gel Electrophoresis --- p.43 / Chapter 2.10.2 --- Activity Staining for Endoglucanases --- p.43 / Chapter 2.10.3 --- Activity Staining for β-Glucosidases --- p.44 / Chapter 2.10.4 --- Protein Staining --- p.44 / Chapter 2.10.5 --- Preparative Polyacrylamide Gel Electrophoresis --- p.44 / Chapter 2.10.6 --- Separation of Proteins and Partial Purification of Different Cellulase Species after Preparative Polyacrylamide Gel Electrophoresis --- p.45 / Chapter Chapter 3 --- Results / Chapter 3.1 --- Determination of the Optimal pH for Fungal Growth --- p.46 / Chapter 3.2 --- Determination of the Optimal Temperature for Cellulolytic and Xylanolytic Enzyme Activity --- p.48 / Chapter 3.3 --- Determination of the Optimal pH for Enzyme Reaction --- p.64 / Chapter 3.4 --- Time Course Experiments on the Production of Cellulolytic and Hemicellulolytic Enzymes --- p.72 / Chapter 3.4.1 --- Production of Cellulolytic Enzymes --- p.72 / Chapter 3.4.2 --- Production of Hemicellulolytic Enzymes --- p.77 / Chapter 3.5 --- Determination of Enzyme Induction Patterns --- p.82 / Chapter 3.5.1 --- Induction of Exoglucanase Production --- p.82 / Chapter 3.5.2 --- Induction of Endoglucanase Production --- p.84 / Chapter 3.5.3 --- Induction of Extracellular β-Glucosidase Production --- p.86 / Chapter 3.5.4 --- Induction of β-Xylanase Production --- p.88 / Chapter 3.5.5 --- Induction of Extracellular β-Xylosidase Production --- p.90 / Chapter 3.5.6 --- Changes in Extracellular Protein Levels in DMS Media Supplemented with Different Substrates --- p.92 / Chapter 3.5.7 --- Changes in Reducing Sugar Levels in DMS Media Supplemented with Different Substrates --- p.94 / Chapter 3.6 --- Partial Purification of Different Cellulases Species Produced by Flammulina velutipes --- p.96 / Chapter 3.6.1 --- Native Polyacrylamide Gel Electrophoresis --- p.96 / Chapter 3.6.2 --- Activity Staining for Endoglucanases --- p.96 / Chapter 3.6.3 --- Activity Staining for β-Glucosidases --- p.96 / Chapter 3.6.4 --- Assay of Cellulolytic Enzymes after Preparative Polyacrylamide Gel Electrophoresis --- p.101 / Chapter Chapter 4 --- Discussion / Chapter 4.1 --- Optimal Conditions for Cellulolytic and Hemicellulolytic Enzymes of F. velutipes --- p.105 / Chapter 4.1.1 --- Optimal Temperature for Enzymic Reaction --- p.105 / Chapter 4.1.2 --- Optimal pH for Enzymic Reaction --- p.106 / Chapter 4.2 --- Production of Cellulolytic and Hemicellulolytic Enzymes --- p.109 / Chapter 4.2.1 --- Production of Cellulolytic Enzymes --- p.109 / Chapter 4.2.2 --- Production of Hemicellulolytic Enzymes --- p.110 / Chapter 4.3 --- Enzyme Induction Patterns --- p.111 / Chapter 4.4 --- Partial Purification of Different Cellulase Species Produced by Flammulina velutipes --- p.116 / Chapter 4.5 --- Conclusion --- p.121 / Chapter 4.6 --- Further Studies --- p.123 / List of References --- p.124

by Joyce Chui Kwan Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 61-75). / Abstracts in English and Chinese. / Acknowledgments --- p.i / List of Abbreviations --- p.iii / Abstract / English --- p.1 / Chinese --- p.2 / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Tumor Formation --- p.3 / Chapter 1.2 --- Anti-tumor Pathways --- p.4 / Chapter 1.3 --- Aim of Project --- p.13 / Chapter Chapter 2 --- The In Vivo effect of Polysaccharopeptide / Chapter 2.1 --- Introduction --- p.15 / Chapter 2.2 --- Materials and Methods --- p.17 / Chapter 2.3 --- Results --- p.18 / Chapter 2.4 --- Discussion --- p.19 / Chapter Chapter 3 --- Cytotoxicity / Chapter 3.1 --- Introduction --- p.23 / Chapter 3.2 --- Materials and Methods --- p.26 / Chapter 3.3 --- Results --- p.28 / Chapter 3.4 --- Discussion --- p.28 / Chapter Chapter 4 --- Anti-angiogenic Effect / Chapter 4.1 --- Introduction --- p.30 / Chapter 4.2 --- Materials and Methods --- p.35 / Chapter 4.3 --- Results --- p.39 / Chapter 4.4 --- Discussion --- p.42 / Chapter Chapter 5 --- Immunomodulation / Chapter 5.1 --- Introduction --- p.45 / Chapter 5.2 --- Materials and Methods --- p.47 / Chapter 5.3 --- Results --- p.50 / Chapter 5.4 --- Discussion --- p.52 / Chapter Chapter 6 --- General Discussion --- p.57 / References --- p.61

Pan, Wenliang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 138-163). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.