Tea is a drink the Western world associates with Britain. Yet at one time tea was new and exotic. After tea was introduced to Britain, tea went through a series of social transformations. The British gradually accepted tea consumption as a sign of gentility and all social classes enjoyed the drink. After 1834, when the East India Company lost their monopoly on the trade with China, a new tea industry began in India and control passed to British entrepreneurs. Faced with difficulty in their efforts to make their industry into a facsimile of Chinese methods, the British reconstituted their tea industry from the ground up. British ingenuity flourished under the guidance of innovators with machines reshaping the industry. As tea became part of British society and industry, an image of tea formed. Advertising brought that image to the public, who accepted the concept of a proper cup of tea.

The tea plant, Camellia sinensis, is a fluoride (F) accumulator. Upon brewing, tea releases large amounts of F. Excessive amounts of F can cause dental fluorosis (DF) and skeletal fluorosis (SF). This study aims to determine the F levels in 4 brands of green tea and 4 brands of black tea. F was measured using an ion selective electrode (ISE) in 3 analyses: i) standard tea infusion, ii) infusion over time with spectrophotometric determination, and iii) microwave digestion. By considering the existing literature and the results of this study, the health risk associated with consuming these 8 brands of tea is evaluated. In accordance with the literature, black tea infusions have significantly higher F than green tea infusions (p < 0.01). As the brew with the significantly highest F concentration (4.07 mg L-1 ), Tetley was chosen to demonstrate the relationship between infusion time and F concentration. As expected, both F concentration and absorbance increase with infusion time. The microwave digestion results are less conclusive. There is no significant difference between the dry mass of F (mg kg-1 ) in green and black tea. Across all samples, approximately 10-31% of the total F is released after 2 minutes of infusion. These results suggest that chronic tea consumption could cause DF and SF. A cup of Tetley tea contains 0.81 mg of F. Only 7.4 or 2.2 cups of Tetley tea would need to be consumed by an adult or child, respectively, to exceed the daily upper limit at which symptoms of SF can arise. Considering the multiple other dietary fluoride sources and the increased susceptibility of children, F in tea should be more closely monitored.

Environmental contamination is a public health concern. In particular persistent organic pollutants like Polychlorinated Biphenyls (PCBs) have been associated with multiple chronic inflammatory diseases, including non-alcoholic fatty liver disease (NAFLD). NAFLD prevalence has steadily increased and is expected to continue to rise with an estimated 25% of the world’s population and 80-100 million people affected in the United States alone. Importantly, the liver is the primary site for endobiotic and xenobiotic metabolism, hence its proper function is critical for the body’s response to innate and extrinsic molecules. One way to combat the deleterious effects of PCB toxicity and fatty liver disease is by increasing consumption of beverages and foods that contain beneficial bioactive nutrients, like dietary polyphenols. However, the biological properties of these dietary compounds are subject to their bioavailability which is directly dependent on the activity of the liver. The first aim of this dissertation was to test the hypothesis that in the presence of a compromised liver, PCB-126 toxicity is altered. Indeed, hepatic and systemic PCB-126 toxicity was exacerbated in this severe liver injury mouse model with an observed increase in hepatic inflammation, systemic inflammation, and early markers of endothelial cell dysfunction. Interestingly, we also observed an increase in the novel gut-liver axis derived cardiovascular disease (CVD) marker trimethylamine-N-oxide (TMAO). Taken altogether, aim 1 proved that a compromised liver can alter PCB toxicity, with implications of the gut microbiota in disease pathology. In aim 2 we investigated whether GTE can protect against MCD-induced hepatic toxicity and development of NAFLD. Results indicated that MCD mice exhibited severe liver injury and gut dysbiosis and unexpectedly, GTE had no protective effects. Interestingly MCD mice displayed differential epigallocatechin-3-gallate (EGCG) metabolism at the hepatic and gut microbiota level, which may alter polyphenol bioavailability and therapeutic potential. Overall, the results provide insight into how a dysfunctional liver and gut dysbiosis can alter polyphenol metabolism, possibly reducing its therapeutic efficiency. In aim 3 we sought to determine potential protective effects of a prebiotic in this mouse model. MCD-fed mice were exposed to PCB-126 with or without inulin supplementation. Although findings from this study are preliminary, our evidence indicates that inulin restores body weight and body composition in this MCD+PCB mouse model and alters the expression of Cyp1a1 in PCB exposed mice, suggesting that inulin’s protective effects may be a result of its ability to interact with the AhR pathway. However further analysis will need to be done to examine the effects of inulin on hepatic, systemic, and gut microbiota endpoints. Overall the data contained in this dissertation suggests that in the presence of a compromised liver both pollutant toxicity and nutrient metabolism are altered, with implications of the gut-microbiota in disease risk. These findings suggest that individuals with end stage liver injury may be more susceptible to pollutant-induced toxicity and nutritional intervention may be unsuccessful at mitigating disease risk.

Thesis (M.Sc.) --University of Limpopo, Turfloop Campus, 2010 / A study was conducted to determine the effect of fermentation temperature and duration on chemical composition of bush tea (Athrixia phylicoides DC.). Bush tea was fermented in incubators at different temperatures and for different lengths of time for quality improvement. Treatments for fermentation temperature consisted of control (24°C; room temperature), 30°C, 34°C, 38°C and 42°C where the tea leaves were fermented for 30 minutes. Treatments for fermentation time consisted of control (0), 60, 90, and 120 minutes at an incubator temperature of 22-26°C. A completely randomized design (CRD) was used with three replicates for both evaluations. The chemical analysis (polyphenols, tannins and antioxidants) were done using Waterman and Mole (1994) method. The results of this study demonstrated that fermentation temperature significantly increases polyphenols at 30, 34, and 38°C whereas tannin content showed a great reduction at 38 and 42°C. Increasing fermentation time achieved a significant increase in both polyphenols (60 and 90 minutes) and tannin contents (90 and 120 minutes). However, changes in either fermentation temperature or time did not give any significant influence on antioxidant content of bush tea. / National Research Foundation

Thesis (M.Sc)--University of Limpopo, 2010. / Black tea (Camellia sinensis) and black tea combined with bush tea (Athrixia phylicoides) were analyzed for their polyphenol content, antioxidant activity and tannin content. Solvent extraction methods were used for extracting polyphenols, antioxidant activity and tannin content. Total phenols were determined using the Folin-Ciocalteu method, antioxidant activity using Trolox Equivalent Antioxidant Capacity (TEAC) assay and tannin content using vanillin-HCl method. Polyphenol content, antioxidant activity and tannin content were calculated using regression equation Y=MX+C, where C=intercept, Y= Absorbance of the sample and M= Gradient. Results of black tea in this study showed that total polyphenols, antioxidant activity and tannin content decreased with decrease in temperature and time and this was attributed to the release of polysaccharides at 90°C. At 90°C for 3 minutes 7.68mg/100g of total polyphenol, 3.85μmol/g of antioxidants and 2.81mg/100g of tannin were obtained and this amount decreased to 5.50mg/100mg for total polyphenols, 1.31μmol/g for antioxidant activity and 0.72mg/100mg for tannin content at 30°C for 10 minutes. Combining the two tea types (50:50) resulted in a significant (p<0.005) decrease in total polyphenols, antioxidant and tannin content. Results of this study showed that at high temperature of 90°C for 3 minutes 2.64mg/100g for total polyphenol, 2.48μmol/g for antioxidants and 1.8mg/100g for tannin were obtained and these amounts decreased to 1.39mg/100mg for total polyphenols, 0.35μmol/g for antioxidant activity and 0.64mg/100mg for tannin content at 30°C for 10 minutes. Thus high brewing temperature causes increase in total polyphenols, antioxidant activity and tannin content of the combined teas. This study showed that black tea and combined black tea and bush tea solutions had large TEAC radical scavenging activity which can be related to total polyphenols and catechins. The antioxidant activity of the tea solution increased with increase in extraction temperature and duration of soaking. It is recommended that 3-min soaking temperature of 90 °C of black tea and combined bush tea and black tea can be used due to the highest total polyphenols and antioxidant activity obtained.

Thesis(M.Sc)--University of Limpopo, 2010. / Bush tea (Athrixia phylicoides DC.) has received interest as another indigenous South African herbal tea with potential for commercialization. The success of commercialization of bush tea hinges on maintenance or enhancement of quality of bush tea as a herbal beverage. Herbal tea quality is one of the critical factors in commercialization that would determine the price of tea for local sale and export. A research was conducted to determine chemical profiles of bush tea at different phenological stages and as influenced by pruning and application of growth regulators. A trial to determine the quality of tea harvested at various phenological stages (namely new growth, older growth and whole plants) from wild and cultivated bush tea was conducted. This was to help determine the best phenological stage to harvest bush tea of best quality. In cultivated bush tea, harvested new growth or as whole plants proved to be of higher quality owing to their higher polyphenol and tannin attributes respectively. In wild bush tea, both new and older growth proved to be of good quality owing to the higher total polyphenol content and higher total antioxidants, respectively. A trial to determine the effect of pruning at different heights on growth and quality of bush tea was also conducted. Pruning of bush tea largely led to yield reduction. Unpruned tea plants remained the tallest plants, with higher number of branches, bigger leaf area and a larger biomass than apically, middle and base pruned bush tea plants. Pruning at different heights also proved to have little or no effect on quality of bush tea. While only total polyphenols remained higher in unpruned tea plants, no significant differences were observed in tannin and total antioxidant content in unpruned, apically, middle and base pruned tea plants. A third trial was conducted to investigate the effects of gibberellins on sprouting and quality of bush tea. The trial results showed that gibberellin application had a iv favourable effect on growth of bush tea, with application of 3% and 4% yielding the highest growth. The results also indicated a declining total polyphenol and antioxidant content with increasing gibberellin application rate, while tannins peaked at 2% application rate.

The production of alternative transportation fuels is imperative to meet future energy demands without contributing to global climate change. Advances in alternative processing techniques that have emerged due to interest in microalgae as a feedstock have led to a variety of potential processing pathways for the production of bio-based fuels. A major hurdle in the algal production process is maintaining a fast and stable algae culture. Monocultures, developed for their high lipid content, suffer from low productivity, are susceptible to crashes and require a constant supply of carbon dioxide to maintain productivity. In an effort to circumvent these obstacles, algal turf scrubber systems (ATS) are now being targeted not only for water purification, but as a means of producing algae feedstocks for fuel conversion. The resulting algae are capable of being harvested at a much higher density, requiring less energy for dewatering purposes. ATS systems do present other drawbacks that downstream technologies need to account for to make this system a viable means for fuel conversion. While polyculture algae species display great growth characteristics, they contain high percentages of nitrogen containing proteins and low lipid content. If not removed this nitrogen pollutes any resulting biocrude making it unacceptable for diesel fuel blends. This study investigates a processing method which reduces the nitrogen content of the resulting fuel by fermenting both carbohydrates and proteins into intermediate compounds. By tuning the E. coli fermentation stain it is hoped that the process will yield higher value co-products than those investigated in this study. The research contained herein incorporates laboratory experimentation with engineering systems modeling to assess the economic feasibility and environmental impacts of generating biofuels from ATS cultivated algae. Results show a minimum fuel selling price of $5.93 per gasoline gallon equivalent and greenhouse gas emissions of -0.0185 kg CO2eq per MJ fuel. Discussion points include process optimization in terms of minimum fuel selling price and global warming potential.

This thesis is concerned with the use of natural waste materials, specifically used tea leaves and coffee grounds, as adsorbents for the removal of trace metals from water, e.g. in waste water treatment. Trace metals such as lead, mercury, zinc, copper, nickel and cadmium are released to the environment in waste water as a result of human activities, and generate concern because of their potential toxicity, persistence and tendency to become concentrated in food chains. While there are many conventional methods for removing these metals from waste water, such as chemical precipitation, ion exchange, membrane technologies and electrochemical treatment, these processes can be expensive. Thus in recent years there has been increasing interest in low cost adsorbent materials as alternative adsorbents, particularly waste natural products such as rice hulls and spent coffee grounds. Most of the research reported in this thesis has been conducted with spent coffee grounds, both grounds produced by leaching of commercial ground coffee and spent grounds obtained from the manufacture of instant coffee. However, some preliminary work was also conducted using spent tea leaves. In the initial work, the adsorption of the metal ions Cu�⁺, Zn�⁺, Cd�⁺ and Pb�⁺ by these adsorbents was investigated using batch adsorption methods to determine the effects of pH, metal ion concentration, adsorbent concentration and other factors such as temperature and metal ion competition. The competitive effects of soluble material leached from the adsorbents that also bind metal ions were studied. The adsorption of the metal ions was found to follow the Langmuir adsorption isotherm. However, the maximum adsorption density was found to depend on the concentration of coffee adsorbent present. Further investigation indicated that this was a result of flocculation of the coffee solids, which acted to reduce the available surface area and thus the maximum density of adsorption sites. This was confirmed using a dispersant to break up the flocculated solids. Column adsorption studies showed that metal ions adsorbed by coffee grounds could be quantitatively leached in dilute acid solution without any loss of subsequent adsorption properties, thus promoting efficient re-use of the column for many adsorption cycles. The adsorbent was also found to be largely unaffected by biological degradation. A prototype waste water treatment column was used to treat tap water samples, with and without known additions of metal ions. The results showed that the grounds efficiently adsorbed trace metal contaminants at levels as low as [mu]g L⁻�. The acid base chemistry of both tea leaves and coffee grounds, and the soluble materials leached from the fresh tea and coffee, were studied using potentiometric titration. In addition the stoichiometry of H⁺ released during metal ion adsorption was also investigated. The latter results indicated that the stoichiometry of metal ion adsorption is not simple, i.e. it probably involves more than one type of adsorption site. The results of this thesis suggest that the use of waste coffee grounds shows considerable promise for the treatment of waste water containing trace metals, and provides an alternative commercial use for such exhausted coffee materials.

During the past decades, the incidence of osteoporotic fractures has increased dramatically in the Western world. Consumption of coffee and intake of caffeine have in some studies been found to be associated with increased risk of osteoporotic fractures, but overall results from previous research are inconsistent. Despite weak evidence, some osteoporosis organisations recommend limiting daily coffee or caffeine intake. The primary aim of this thesis was to study the association between long-term consumption of coffee and bone mineral density (BMD), incidence of osteoporosis and fractures. A secondary aim was to study the relation between tea consumption and fracture risk. An increased risk of osteoporotic fractures in individuals who consumed ≥ 4 cups of coffee vs &lt; 1 cup coffee per day was demonstrated in a study of 31,257 Swedish middle-aged and elderly women (a part of the Swedish Mammography Cohort - SMC) when calcium intake was low (&lt; 700 mg/day). However, no higher risks of osteoporosis or fractures were observed in the full SMC with increasing coffee consumption. In the full SMC (n = 61,433) the follow-up was longer and the number of fractures was higher. Similarly, no statistically significant associations between consumption of coffee (≥ 4 cups of coffee vs &lt; 1 cup) and incidence of osteoporotic fractures were observed in the Cohort of Swedish Men (COSM), including 45,339 men. Calcium intake did not modify the results from the investigations performed in the full SMC or COSM. Nonetheless, a 2 - 4% lower BMD at measured sites was observed in men participating in the PIVUS cohort and in women from a sub-cohort of the SMC who consumed ≥ 4 cups of coffee vs &lt; 1 cup daily. Individuals with high coffee intake and rapid metabolism of caffeine had lower BMD at the femoral neck. No association between tea consumption and risk of fractures was found in the studies. In conclusion, the findings presented in this thesis demonstrate that high consumption of coffee may be associated with a modest decrease in BMD. However, there was no evidence of a substantially increased incidence of osteoporosis or fractures typically associated with osteoporosis.

In recent years, the development of power line communication and relational application is gradually attracted much attention. The use of power line system is able to achieve home network automation, automatic meter reading, and demand supply management, so it can be a great help for the current emphasis on energy conservation ideas. Therefore, many international organizations and national programs involve in researches. The signal is vulnerable to the environment causing data error in the power line transmission, so that we reduce the use of power line communication. For making great application of power line system, the main purpose of the thesis is to study that ensure the data accuracy, integrity and security through power line transmission. Therefore, we designed the digital chip for power line communication. We achieve the signal transmission with the half-duplex ability through power line by digital chip designing and solve error problems about transmitting data. By designing the modules of digital circuit, the chip can encrypt/decrypt data, correct error-bits of data, detect accuracy of data, process control signals, and modulate/demodulate signals. The purpose is for increasing data accuracy in PLC transmission. The chip design adopts TSMC 0.18£gm process as full digital circuits and applies to the energy meter management.