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Theses and dissertations (Applied Sciences)

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Has files: YesSubject: search.filters.subject.Oils and fats, Edible

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    Assessment of a biological nutrient removal process for the remediation of edible oil effluent
    (2002-05-10) Mkhize, Sandile Psychology; Bux, Faizal
    Eutrophication is a natural process that is greatly aggravated by the action of man in the natural environment. Deterioration of South Africa's natural water resources results directly or indirectly from the discharge of industrial effluent rich in nutrient nitrogen and phosphorus. The South African edible oil refmeries generally discharge poor quality effluent which impacts negatively on the water resources and wastewater treatment installations. The main aim of this study was to assess the capacity of a laboratory scale effluent treatment process that will produce final effluent of acceptable quality with regards to organic load and phosphate concentration prior to its discharge into the municipal sewerage system. The study was conducted in three stages: wastewater characterization, treatability studies, and laboratory scale treatment investigations. After analysing various effluent parameters, treatability studies were conducted using an aerobic-anaerobic sequencing batch reactor with a total hydraulic retention time of 24 hours. The results showed an average of 75 % reduction of COD and more than 90 % removal of fats, oils and grease (FOG). Based on the results of effluent characterisation and treatability studies, a laboratory scale activated sludge effluent treatment process was designed and operated with two bioreactors (aerobic and anaerobic) in series. The system was operated for a period of one-month resulting in 70 % removal of COD and 4% reduction in phosphate (P04-P). After some structural and operational changes from the original design configuration, the system was the operated continuously for the duration of the study period. An optimum COD removal of 75 % and 107 mgll P04-P reduction was achieved during the last operational phase of the system. More than 95 % reduction in fats, oils and grease (FOG) had been achieved in both semi-continuously and continuously operated systems.b.7
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    Quality assessment of frying oils in the formal and informal food preparation sectors
    (1998) Mewa, Choonilall; Starkey, Anthony Roland
    The demand for fried foods by the public and the number of people entering the fried food industry in the form of take-aways and fast food outlets both in the formal and informal sectors has increased tremendously. Frying fats and oils are very expensive, used in large quantities and is the most important ingredient used in the preparation of fried foods: Due to the high cost of these frying fats and oils, majority of the formal and informal traders are using the frying fats and oils to its maximum in order to reduce the overall cost. This has resulted in the preparation of poor quality offried foods. Considering all of the above, the aim of the proposed research was :- (a) to determine the quality of the frying fats and oils used by both the formal and informal sectors by performing both physical and chemical analyses and compare these with similar analyses performed on the unused frying fats and oils in order to ascertain the degree of deterioration of the used frying fats and oils (b) to investigate the method of disposal of the used frying fats and oils. (c) to contribute in educating both the consumers and the suppliers of fried foods by bringing the findings of this research to the attention of the Durban Metro Health Department. The used frying fats 'and oils were collected during the frying process by the environment health officer from the Durban Metro Health Department. These samples were placed in a refridgerator to prevent any further deterioration. The used and unused frying fats and oils were analysed for, the Free Fatty Acid and Acid Value contents; the quantitative separation of Monoglycerides, Diglycerides and Triglycerides; the Refractive Index; the Peroxide Values; the concentrations of Polar and Non-polar Compounds; the Viscosity and the identification of the various fatty acid methyl esters present in the samples. The analytical methods used were followed from the American Oil Chemists Society (AOCS) Official Method Handbook. The Free Fatty Acid and Acid Value results showed that twenty-five percent of the samples had a concentration of more than the maximum acceptable limit of 2.5%. It was evident that the types of food fried, the intermittent heating, frying
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    Optimization of riboflavin production by fungi on edible oil effluent
    (2010) Swalaha, Feroz Mahomed; Odhav, Bharti
    South African edible oil processing plants produce approximately 3 x 105 tonnes of oil annually with up to 3 tonnes of water for every tonne of oil produced. Wastewater that contains oil extracts varies in organic loading from 30,000 to 60,000 mg.l-1 COD. This wastewater can be used to grow oleophilic fungi to produce valuable industrial products. The global vitamin B market is approximately R25.5 billion with 4500 metric tonnes being produced. A large proportion of this is produced using the fungus Eremothecium gossypii using oil substrates. The aim of this study was to to develop a novel method to produce riboflavin with the aid of fungi, using edible oil effluent (EOE) as substrate, and to optimize the production thereof by statistical experimental design. Four fungi were surveyed for their growth potential on EOE and two, E. gossypii (CBS109.51) and C. famata (ATCC 208.50) were found to produce sufficient riboflavin for further study. Mutation of these organisms using ethylmethane sulphonate (EMS) increased riboflavin production from 3.52 mg.l-1 to 38.98 mg.l-1, an 11-fold increase. An enzyme pathway responsible for this was found to involve isocitrate lyase and comparison of this enzyme’s activity in the mutant against the wild-type using Michaelis-Menten kinetics showed a higher reaction velocity (Vmax) with a reduced substrate affinity (Km) indicating that the mutation was associated with this enzyme. Biomass comparisons were fitted to the sigmoid Gompertz model which was used to compare the wild-type to the mutant and increased specific growth rates and doubling times were observed in mutated cultures of E. gossypi. A strategy of statistical experimental design was pursued to optimize media components and iterative fractional factorial experiments culminating in a central composite optimization experiment were conducted. Statistically verified mathematical models were developed at each stage to identify important media components, predict media interactions, show directions for improvement and finally, predict maximum riboflavin production. An eight-factor resolution IV fractional factorial increased riboflavin production to 112 mg.l-1 followed by a four-factor resolution V experimental design which increased riboflavin production to 123 mg.l-1. A two-factor (yeast extract and NaCl) central composite experimental design predicted a maximum riboflavin production of 136 mg.l-1 which was a 3.5-fold increase from the mutant, and 38.6-fold higher than the E. gossypii wild-type. The optimized value was achieved within predicted confidence intervals in confirmatory experiments. Cost implications for production of riboflavin on EOE were calculated and a 10% technology uptake by the edible oil industry could yield a riboflavin industry with a 63.65 million rand turnover and a potential 24.96 million rand gross profit margin.