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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Technical and economic study of plantain food products

Ogazi, P. O. January 1982 (has links)
Plantain (Banana-Musa AAB) is a widely growing but commercially underexploited tropical fruit. This study demonstrates the processing of plantain to flour and extends its use and convenience as a constituent of bread, cake and biscuit. Plantain was peeled, dried and milled to produce flour. Proximate analysis was carried out on the flour to determine the food composition. Drying at temperatures below 70ºC produced light coloured plantain flour. Experiments were carried out to determine the mechanism of drying, the heat and mass transfer coefficients, effect of air velocity, temperature and cube size on the rate of drying of plantain cubes. The drying was diffusion controlled. Pilot scale drying of plantain cubes in a cabinet dryer showed no significant increase of drying rate above 70ºC. In the temperature range found most suitable for plantain drying (ie 60 to 70ºC) the total drying time was adequately predicted using a modified equation based on Fick's Law provided the cube temperature was taken to be about 5ºC below the actual drying air temperature. Studies of baking properties of plantain flour revealed that plantain flour can be substituted for strong wheat flour up to 15% for bread making and up to 50% for madeira cake. A shortcake biscuit was produced using 100% plantain flour and test-marketed. Detailed economic studies showed that the production of plantain fruit and its processing into flour would be economically viable in Nigeria when the flour is sold at the wholesale price of NO.65 per kilogram provided a minimum sale of 25% plantain suckers. There is need for government subsidy if plantain flour is to compete with imported wheat flour. The broader economic benefits accruing from the processing of plantain fruit into flour and its use in bakery products include employment opportunity, savings in foreign exchange and stimulus to home agriculture.
2

Strategies for agricultural change and the UK balance of payments

Blackman, C. R. January 1981 (has links)
The world food crisis, Britain's reliance on imported food and feedstuffs and balance of payments difficulties were some of the factors which lent weight to the call for increased self-sufficiency in Britain's agriculture in the 1970s. This project considers two main areas: an investigation of the impact of radical agricultural change, designed to increase self-sufficiency, on the balance of payments; and, an appraisal of the potential role of the food industry within a radically different food system" The study proceeded by: an examination of the principles of agricultural policy and its development in Britain; an overview of the mechanism and meaning of the balance of payments; a consideration of the debate on agricultural import saving; the construction of radical agricultural strategies; the estimation of effects of the strategies , particularly to the balance of payments the role of the food industry and possible innovations within the strategies; a case study of textured vegetable proteins and" the wider implications of implememtation of radical agricultural alternatives. Two strategies were considered a vegan system, involving no livestock and an intermediate system including some livestock and dairy cattle. The study concludes that although agricultural change could principle make a contribution to the balance of payments, implementation of agricultural change cannot be justified for this purpose alone. First, balance of payments problems can be solved by more appropriate methods. Second, the UK' s balance of payments problem haa disappeared for the time being owing to North Sea oil and economic recession. Third, the political and social consequences of the changes investigated would be unacceptable. Progress in UK food policy is likely to be in the form of an integrated food and health policy.
3

The role of sugars and sugar metabolism genes (sucrose synthase) in Arabidopsis thaliana seed development

Odunlami, Benjamin Oladipo January 2009 (has links)
Seed development in Arabidopsis thaliana, has been studied at several levels. However, little has been done to study the role of sugar metabolism genes in seed pod development in this species. As the fertilized egg progresses to a mature seed, the sugars composition during different stages of the developing changes. These changes are related to metabolic processes in the developing seeds, but also to the activity of sucrose- converting and transporting genes, active at the interphase between the maternal tissue and the endosperm. Sucrose synthase (SUS) is one of these genes; it catalyses the reversible reaction of sucrose breakdown in the presence of UDP to form fructose and UDP-glucose. In this study we looked at glucose, fructose and sucrose concentration at different time points during seed pod development. These changes in sugar concentrations were analysed in both Colombia wild type and WS (Wassilewskija) ecotypes. By comparison of the sugar composition of these ecotypes, and linking these data with phenotypic observations in both ecotypes during development, we are able to comment on the possible role of sugars in seed pod development. Also, the sugar composition of wild type seed pods were compared with those of Atsus mutant seed pods, and possible effects sucrose synthase mutations on the phenotype of the developing Arabidopsis thaliana seeds were analysed. The effect of sucrose synthase knockouts in developing seed pods were studied by comparing biochemical and phenotypic characteristics data of the Atsus mutants within Colombia wild type plants. Salk line plants were screened to identify plants carrying a homozygous insertion for T-DNA in five of the sucrose synthase genes. The developing seed pods of each of the homozygous mutants were characterized biochemically via High-Performance Anion-Exchange Chromatography (HPAEC). Furthermore, seed weight, number of seed per pod, germination rate and the morphological development of the embryo were closely analysed. The study found out that there were some biochemical effects of Atsus knockout mutants, and some phenotypic effects of Atsus knockout mutants on the developing seed pods. However, in general the effects were not as pronounced as those that were seen in maize seed, pea seed and potato tuber as a result of sucrose synthase knockout. The general pattern of glucose, fructose and sucrose were similar to the Colombia wild type, although in mature seed pods the sucrose levels in Atsus1, Atsus2, Atsus3 and Atsus6 were slightly, but significantly lower than in the Colombia wild type.
4

Supply linkages and power relations in the UK agro-food system

Allinson, Johanne Claire January 2004 (has links)
No description available.
5

Development and evaluation of an LC-ESI-MS method for the simultaneous detection of five major opium alkaloids

Carlin, Michelle January 2015 (has links)
The aim of this work was to establish an analytical method for the simultaneous detection of five major opium alkaloids in poppy seeds by liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS). Once opium alkaloids were detected in poppy seeds, toxicological studies were carried out to establish if these compounds were detected in oral fluid (OF) of participants who ingested muffins containing poppy seeds. It is known that the ingestion of poppy seeds has caused positive opiate drug test results and much work has been reported in the scientific literature in the last 20 years. Researchers in the field have investigated alternatives to differentiate between heroin administration and that of other opiate drugs versus poppy seed ingestion. Most of the work which has been carried out relates to establishing illicit heroin use by examining biological matrices for the presence of acetylcodeine, thebaine, papaverine, noscapine and their associated metabolites. The research methodology consisted of establishing an LC-ESI-MS method for the simultaneous detection of five major opium alkaloids (morphine, codeine, thebaine, papaverine and noscapine). A deuterated internal standard (morphine-d3) was used for the quantitation of alkaloids in harvested poppy seeds and oral fluid samples. Due to technical difficulties, 3 LC-MS instruments were employed in this work. Electrospray ionisation was employed in all mass spectrometers but the analysers included an ion trap with octopole, a triple quadrupole and a hybrid quadrupole Orbitrap. Suitable extraction procedures were determined and harvested seeds purchased from a number of supermarkets were analysed for the presence of five alkaloid compounds using the LC-MS method. A small scale pilot study with 6 participants was carried out to establish if it was possible to fail an OF drug test for opiates after consuming poppy seed muffins. OF samples were collected post ingestion using Quantisal™ kits and the level of each of the opiates was monitored. The findings were that an LC-ESI-MS method was established for the simultaneous detection and quantitation of five major alkaloids. However, the method development process involved finding a solution to co-elution of morphine and codeine. The process also included resolving the issue of thebaine producing two peaks with identical mass spectra and separated by a difference of 6 minutes in retention time. Varying levels of alkaloids were identified in harvested poppy seeds: levels of these compounds differed considerably within and between batches of poppy seeds. These findings could be attributed to a number of factors, for example, where and how the plants were grown and methods of harvesting. Two poppy seed muffins were consumed as part of a toxicology study. Morphine was detected in the 5 minute sample in 5 out of the 6 participants with concentrations in OF of 0.5-0.8 ng mL-1; codeine was detected in 2 of the 6 participants at 1.5 and 2.6 ng mL-1. Thebaine, noscapine and papaverine were also detected in OF of a number of participants, which has not been previously reported in the literature. However, it should be noted that the values calculated are only estimated since the peak area ratios obtained were found to be less than the lowest concentration (10 ng mL-1) in the linear calibration range. In conclusion, an LC-ESI-MS method for the simultaneous detection and quantitation of five major opium alkaloids has been established and has been used to detect alkaloids in harvested poppy seeds and oral fluid samples. From a small pilot toxicology study, oral fluid results indicate that levels of morphine and codeine do not exceed the SAMSHA 40 ng mL-1 cut-off after ingestion of a realistic amount of poppy seeds contained within bakery products.

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