Theses and dissertations (Applied Sciences)
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Item Intervention effect of food literacy on household food waste in the KwaDukuza municipality(2024-09) Miti, Nosipho; Naicker, Ashika; Grobbelaar, Hendrina HelenaBackground: Approximately one-third of the food produced for human consumption is lost annually across the global food supply chain. In South Africa, it is estimated that around 10.3 million tonnes of food are wasted each year. Despite food waste occurring at various stages of food production, individual households have been identified as the primary producers of food waste at the consumption stage, driven by consumer behaviour and practice. While food waste is a global concern, South Africa's household food waste mimics that of developed countries. Although household food waste studies in South Africa have gained momentum, nearly all studies focus on household food waste consumer practices. No intervention study has been conducted to change consumer behaviour towards household food waste in South Africa. Likewise, the cost of household food waste, nutritional losses, and the environmental impact of household food waste have yet to be explored through an intervention. Interventions that target a change in human behaviour towards reducing household food waste can make a meaningful impact on food and nutrition security, and the environment. Aim: This study aimed to determine the intervention effect of food literacy on household food waste in the KwaDukuza municipality. Methods: In this randomised control trial (RCT), middle and high Living Standards Measure (LSM) households from five areas in the KwaDukuza municipality used in a formative study to determine household food waste behaviour and practices were eligible to participate in the study. All households at baseline received three colour-coded bins [used to separate food waste by food categories], binliners, food labels and freezer bags to contain cooked food waste. The first objective was to calculate household food waste through a weighed food waste audit at baseline and endline. A weighed food audit was conducted at each household (n=180). Objective two of this study included calculating the cost, associated nutrient losses and environmental impact of household food waste using the results of the food waste audit at baseline and endline. The cost of household food wasted was analysed using the mean price of foods from retail stores in the study area to determine the cost (Rand value) of household food waste at baseline and end line. The nutrient losses were calculated using the South African Medical Research Council Food Finder 3 web-based software at baseline and endline. The environmental impact was calculated using the My Emission Footprint calculator for food wasted at baseline and endline. The third objective of this study was to determine the intervention effect on household food waste. Households were randomly assigned into three intervention groups, intervention 1 (n=60), intervention 2 (n=60), and the control group (n=60). Households who were part of Intervention 1 received the food literacy toolkit and food literacy lessons on how to reduce household food waste; households in intervention 2 received the food literacy toolkits only and were reliant on self-efficacy to use the toolkit and households that were part of the control group did not receive any intervention. Results: Findings from the food waste audit showed that at baseline, the total mean of household food waste produced by all households (n=180) in this study was 1.53 kg (1531.29 g) per week, decreasing to 0.31 kg (307.47 g) per household/ week at the endline. A significant reduction of household food waste was recorded post-intervention (average waste per household = 307.47 g) When household food waste was separated into categories of the type of food wasted, the fresh produce pre-intervention (average waste per household = 917.73 g) was significantly more than the fresh produce postintervention (average waste = 173.43g). Meat produce wasted pre- (average waste per household = 109.56g) also surpassed the meat produce wasted post- (average waste per household = 43.26g). The cooked food wasted pre- (average waste per household = 387.07 g) was significantly greater than the cooked food post- (average waste per household = 76.39 g)-. The cost of food waste for the whole group pre- (average waste per household = R145.57) was significantly more than the cost of food waste for the whole group post- (average waste per household = R39.75). In terms of the environmental impact, the pre- (average waste per household = 7664.13 gCO2e) exceeded the environmental impact post- (average waste per household = 6407.67 gCO2e). A high nutrient loss from household food waste was recorded at baseline, and there was a significant reduction of macro-and micronutrient nutrient loss at the endline for the whole group (n=180). In intervention 1, intervention 2 and the control group, most nutrient losses such as energy, total protein, total lipids, total carbohydrates, and total dietary fibre were greater during the pre-intervention phase compared to the post-intervention phase. In this RCT, a significant reduction of household food waste was observed for the whole group (n=180) and across intervention groups. Following the 6-week intervention duration, between intervention arms, there was no discernible difference in household food waste, economic loss, nutritional loss and environmental impact. However, for every intervention group, there was a substantial decrease in all measured outcomes from baseline to endline. The main reason for this result could be attributed to the fact that households probably perceived that they were being monitored through the food waste audit at baseline and endline, implying that sensitisation of communities to their actual household food waste can be an impactful intervention strategy to conscientise consumers to reduce their household food waste. Conclusion: This study shows a clear linkage between household food waste, nutrition, economic and environmental impact. The disposal of food waste from households has a substantial and wide-ranging effect on the food chain, leading to various economic, environmental, and social challenges. The social ramifications of food waste are enormous, given the striking difference between the significant amounts wasted in affluent households and the prevalent hunger and food insecurity in many communities. In order to create a food system that is more environmentally friendly and able to withstand challenges, it is crucial to focus on and decrease the amount of food wasted in households. This requires a combined initiative of educating consumers, implementing effective waste management practices, and enacting legislation that encourages responsible consumption.Item The development of a novel universal coating for urological implants(2024-09) Shongwe, Mduduzi Hurmprey; Kudanga, TukayiUrology employs various implants, such as urinary catheters, ureteral stents, and ureteral access sheaths (UASs), to manage diseases associated with the urinary tract system. These implants serve different purposes. For example, urinary catheters are primarily used to drain urine from the bladder, ureteral stents are used to keep the ureteral cavity open for urine passage, and UASs are used in expanding the ureteral cavity to facilitate the introduction of other devices. However, these implants pose challenges due to their invasive nature and inadequate biocompatibility, which can lead to uroepithelial tissue damage (caused by friction) and an increase in the risk of urinary tract infections (UTIs). Urinary tract infections, in turn, can cause blockages that limit the effectiveness of these implants. Therefore, several strategies are currently employed to address these challenges, mainly the use of lubricious hydrophilic polymeric coatings and antimicrobial agents. While some success has been achieved, uroepithelial tissue damage and UTIs remain significant concerns. Furthermore, most of these strategies are tailored to specific urological fabricating materials, limiting their scope. In light of these challenges, this study developed a universal coating technology using polydopamine (PDA) as a versatile primer and polyvinyl pyrrolidone (PVP) as a hydrophilic polymeric top layer loaded with iodine (I2) as an antibacterial agent to improve properties of urological implants. Urological implant fabricating biopolymers including polyurethane (PU) and polydimethylsiloxane (PDMS) were modified with a PDA/PVP coating technology and loaded with various concentrations of I2 (0.1%, 0.5% and 1% w/v). The ability of the coating technology to reduce the friction coefficient of urological biomaterials was evaluated by assessing its ability to introduce lubricity. Other biological effects that characterize the biocompatibility and antimicrobial activity of the coated samples were assessed using relevant standard ISO (International Organization for Standardization) and EUCAST (European Committee on Antimicrobial Susceptibility Testing) In vitro methods. The biocompatibility of the coating technology was assessed by determining their cytotoxicity with the XTT cytotoxicity assay using L292 cells while the brine shrimp lethality assay (BSLA) was carried out as a preliminary animal model study. Their genotoxicity was assessed with the Ames mutachromo assay carried out with Salmonella typhimurium T100 to detect base shift mutation. The antimicrobial activity of the coated technology was determined using the IS0 22196 assay with Escherichia coli (ATCC 25922), the EUCAST disk diffusion and broth microdilution assays with E. coli (ATCC 25922), Proteus mirabilis and the urinary catheter bridge microbial migration assay with E. coli (ATCC 43888). The novel coating technology was adaptable to urological implant fabricating biomaterials with different surface polarities including PDMS and PU. The polydopamine/polyvinyl pyrrolidonecoated biomaterials were observed to have improved lubricity (slipperiness rate of 5 s per 10 mm biomaterial-agar interaction) and the ability to absorb and trap fluids (0.088 ± 0.009 mg/cm2). The concentration of iodine solution (0.1%, 0.5% and 1% w/v) loaded in the coatings significantly influenced their biocompatibility and antimicrobial efficacy. The biocompatibility observations made in the BSLA were mostly in line with the XTT cytotoxicity assay. When an iodine concentration of 0.1% and 0.5% w/v was incorporated, the PDA/PVP-coated biomaterials were not toxic towards L292 cells and not lethal towards brine shrimp larvae after a 24 h exposure period. However, potential lethality towards brine shrimp larvae was only observed in the biomaterial loaded with 0.5% w/v after an exposure period of 48 h. The coated biomaterials without iodine were not toxic while those that were loaded with a concentration of 1% w/v iodine were toxic according to both the XTT assay and BSLA. All the PDA/PVP-coated biomaterial loaded with iodine (0.1%, 0.5% and 1% w/v) did not demonstrate base shift mutations in Ames muta-chrome assay. The ISO 22196 method demonstrated that the PDA/PVP-coated biomaterials loaded with at least 0.1% (w/v) iodine reduced E. coli (ATCC 43888) by at least 2 growth logs. The minimum inhibitory concentration (MIC) for the PU-PDA/PVP (0.1% I2) surfaces was determined to be 40 mm2/ml for E. coli (ATCC 2592) 0.5 McFarland standard. The broth microdilution showed that the MIC of extracts of the PU-PDA/PVP (0.5% I2) to be 3 cm2/ml and of PU-PDA/PVP (1% I2) to be 1.5 cm2/ml for E. coli (25922). However, only the extract of PU-PDA/PVP (1% I2) was effective against P. mirabilis at 3 cm2/ml. In the disk diffusion assay, the PU-PDA/PVP (0.1% I2) was only effective against E. coli (ATCC 25922) with a 1 mm zone of inhibition. The PU-PDA/PVP (0.5% I2) was effective against both E. coli (ATCC 25922) and P. mirabilis with 12.13 ± 1.53 mm and 8.5 ± 0.5 mm zones of inhibition, respectively. PU-PDA/PVP (1% I2) showed the highest zone of inhibition (16.25 ± 1.77 mm) against E. coli (ATCC 25922) and 13 ± 1 mm against P. mirabilis. In the catheter bridge microbial migration assay, E. coli (ATCC 43888) growth across the bridge was observed after 24 h for PDMS and PDMS-PDA/PVP without iodine incorporation, after 48 h for PDMS-PDA/PVP (0.1% I2) and PDMS-PDA/PVP (0.5% I2), and after 72 h for PDMS-PDA/PVP (1% I2). In addition, there was a positive correlation (P<0.05) between the concentration of iodine loaded in the PDA/PVP coated biomaterials and antimicrobial activity (disk diffusion assay) while a negative correlation with biocompatibility (XTT cytotoxicity assay) was observed. Overall, the research demonstrated that a PDA/PVP-coating technology is adaptable for urological biomaterials including PU and PDMS, introduces lubricity on the surface of the biomaterials, and when it is loaded with 0.5% w/v I2, the coating can inhibit the growth of bacteria that cause UTI without causing toxicity in model eukaryotic cells. Therefore, the PDA/PVP (0.5% w/v I2) coating is a promising strategy for improving us.Item Development, validation and implementation of a sustainable, nutrition-sensitive agriculture toolkit to address food and nutrition insecurity in Lesotho(2024-09) Mothepu, Lisebo; Napier, Carin E.; Naicker, Ashika; Duffy, Kevin JanBackground: Global food prices continue to increase because of natural and humaninduced disasterssuch as climate change and war. As a result, poverty remainsrelatively high globally, especially in lower-middle-income countries such as Lesotho. Poverty in Lesotho is rated at 49.7% with a staggering 24% of the population experiencing extreme poverty, and it is mostly prevalent in rural areas. Out of the population of over 2 million, approximately half of the populace survives below the poverty-line, and 58, 000 people continue to experience food insecurity. Lesotho ranks at 121st out of 125 countries with sufficient data to calculate 2023 GHI scores. Thehigherthe rank theworse the hungerindex. The Global Hunger Index recorded Lesotho’s hunger score at 32.4. This is categorised as alarming on the scale ranging from low to extremely alarming. Lesotho has been grappling with chronic food insecurity, with 61% of the population affected living in rural areas and 39% affected living in urban areas due to climate challenges such as heavy rains. In summary, severe food insecurity, decrease agriculture production, poverty, poor nutritional status, and HIV/AIDS decrease the quality of life in Lesotho. Aim: The main aim of the research study was to develop, validate, and implement, a sustainable nutrition-sensitive agriculture toolkit with two programs: sustainable agriculture and sustainable nutrition-sensitive agriculture. The toolkit was developed for rural small-scale female family farmers to provide for household consumption and local small-scale commerce. The study further aimed to introduce and educate female farmers in agri-business and agro- processing through the use of Greenhouse tunnels underpinned by sustainable agriculture, sustainable local community food systems, and sustainable nutrition-sensitive agriculture to address food and nutrition insecurity and attempt to decrease hunger at the community, household, and individual levels. Methodology: The sample size was n=126 females participants residing in rural households in the district of Mohale’s Hoek, Lesotho. The sample population age ranged from 20 to over 60 years. In this randomised control trial (RCT), a combination of quantitative and qualitative methods were used. The quantitative data was used to determine the interaction between socio-economic conditions, nutritional variety, nutritional competence, food consumption patterns, food security status, and agricultural practices. The qualitative data collection used was an observational research method under naturalistic and controlled observation. This approach involved manipulating and controlling the experimental and intervention research variables to determine cause and effect relationships. The control group participants were from Maqoala n=63, and the intervention group participants were from Mpharane n=63. The toolkit was developed using relevant literature for addressing poverty, hunger, food insecurity and nutrition insecurity. In addition, the toolkit was also developed using the results obtained from the study through the administered questionnaires: sociodemographic, household hunger scale and household food insecurity access scale, nutrition knowledge and anthropometry measurements for nutritional assessment, food frequency, 24-hour food recall, agricultural and knowledge practices, preparation, and preservation practices. The toolkit comprised of two programs: sustainable agriculture and sustainable nutrition-sensitive agriculture. The toolkit was validated through the Delphi method. The intervention was run for two years, to target three planting and harvesting seasons in both the control and experimental villages. Both the experimental and control group were allocated Greenhouse tunnels with irrigation systems, temperature control systems, storage facilities and food preparation facilities. The inputs given to each group included the allocation of inputs was seedsthat were certified by the government of Lesotho:round cabbage,spinach (Swiss chard), green beans (snap beans), red beetroot, carrots (Nantes), red bell pepper, tomato (stupice), butternut squash, potato (Vivaldi), and brown onion. The experimental group was given the researcher’s training manual together with the participants training manual. The experimental group was further trained using the manual. The control group, Maqoala, was given the training manuals, without any training. Results: Results indicated that all female participants (n=126) headed the households and were caregivers who resided with other people in the households. The majority of the households (61.9%) had one room, 16.7% had two rooms, and 11.9 % had three rooms with no electricity or running water in the houses. Notably, all participants were unemployed, and experienced anxiety over running out of food before having money to buy more. Almost 44% of the participants often had a shortage of money to buy food, and 45.2% of the participants sometimes had a shortage. The average monthly spending on food for 25.4% of the households was R201 to R300, whilst 36.5% of the households on average spent a between R301 to R400 on food each month. All the participants reported having a change in food intake due to decreased accessibility. Moreover, all the participants indicated that they consumed less food than required and had to cut the size of the food served to children because there was not enough food available. An estimate 89.7% of the participants skipped meals because there was not enough food to eat. The nutrient analysis from the 24-hour food recall indicated dietary inadequacy in energy, protein, calcium, and vitamins A, B6, B12, C, and E. When assessing the dietary diversity, the participants consumed more cereals and starchy foods, as reflected by the high carbohydrate Dietary Reference Intakes (DRIs). The Body Mass Index (BMI) of 4.7% of the participants from Maqoala was in the underweight BMI range compared to 3.1% of participants from Mpharane. The outcomes could also be influenced by a lack of nutrition knowledge as the average knowledge was 52.0%, ranging from 38 to 69% in both Mpharane and Maqoala.The results highlighted high levels of hunger, food insecurity and nutrition insecurity among the participants. The results supported the development, validation, and implementation of the toolkit through the Delphi method. Firstly, the toolkit focused on sustainable agriculture, planting vegetables, selling vegetables to generate money to buy seeds for the subsequent planting phases, and consumption and preservation of vegetables for households in the control and experimental groups. The intervention results indicated that Mpharane (experiment group) participants in phase 1, harvested 468 cabbage heads, sold 278 heads, and preserved 189 heads for household consumption. In phase 2, the number of cabbages increased to 612 heads; the participants sold 422 heads and preserved 189 heads for household consumption. In phase 3, 675 cabbage heads were harvested, 485 heads were sold, and 189 were preserved for household consumption. Mpharane had an increase of 144 heads of cabbage from phase 1, 468 heads of cabbage, to phase 2, 612 heads of cabbage, and in phase 3 (675 heads of cabbage), the increase was very low, with 63 heads of cabbage between phase 2 to phase 3. Maqoala (control group) participants did not sell any of the fresh produce they harvested. Instead, they shared the harvested fresh produce with each other. In phase 1, 567 cabbage heads were harvested, and 567 heads were shared among the n=63 participants for household consumption. In phase 2, the number of cabbage heads harvested increased to 627 heads and all 627 heads were shared among the participantsfor household consumption. In phase 3, 414 cabbage heads were harvested, and 414 heads were shared among the n=63 participants for household consumption. Maqoala produced a total of 1608 heads of cabbage between phases 1, 2 and 3, and Mpharane produced a total of 1755 heads of cabbage between phases 1, 2 and 3, 147 heads of cabbage more than Maqoala. The participants from experimental group harvested 519 bundles of spinach in Phase 1. In Phase 2, 834 bundles were harvested, 329 bundles in Phase 1, 644 bundles in Phase 2 were sold, and 189 bundles were preserved for household consumption. The participants harvested 1238 bundles of spinach in phase 3, and 1048 bundles were sold, whilst 189 were preserved for household consumption. The participants in Maqoala harvested 857 bundles of spinach and used all 857 bundles for household consumption. The experimental group had a vast increase in the bundles of spinach produced in phase 3, with 1238 bundles of spinach compared to phase 1, with 468 bundles, whilst phase 2, produced 612 bundles. The total of the bundles of spinach produced by the experimental group was 2591 bundles between phases 1, 2, and 3, whilst the control group produced 2196 bundles of spinach between phases 1, 2, and 3. The experimental group produced 396 bundles more than the control group. The toolkit introduced and educated the experimental group on agriculture practices, nutrition, and developing market products. At the baseline immediately after the lesson, the participants were assessed and scored 54% in lesson 1, 66% in lesson 2 and 80% in lesson 3. At the endline, the participants were not taught again but were expected to remember the previous lessons and practices they had done during the intervention. There was a decrease in the participants'scores atthe endline. The participantsscored 43% in lesson 1, 32% in lesson 2 and 65% in lesson 3. Conclusion: The findings indicated that poverty contributes to hunger, food and nutrition insecurity, and triple burden of malnutrition: undernutrition and overnutrition, and micronutrient deficiency in Lesotho. Food and nutrition insecurity can be addressed by integrating sustainable agriculture and sustainable nutrition-sensitive agriculture. Agriculture holds significant potential as it can contribute to addressing the primary causes of nutritionrelated problems, enhance worldwide food accessibility and availability and improve family food security, nutritional value, salary, and female empowerment. For these reasons, a sustainable nutrition-sensitive agriculture toolkit for small-scale female farmers with agribusiness and agro-processing components was developed from the Lesotho data and shown to improve household vegetable production and consumption. Agrifood systems contribute to high employment of females worldwide. Agrifood systems also contribute more to the livelihoods of females compared to males, mainly in developing countries. Enriching females and ending genderinequality under agrifood systems can improve the lives of the females and their homes, decrease starvation, increase earnings and strengthen resilience.Item A mucor circinelloides-based integrated biorefinery(2024-09) Zininga, Johnson Tungamirai; Permaul, Kugen; Singh, SurenABSTRACT The utilization of agro-based waste residue is a prominent example for establishing a circular bioeconomy. When agro-based waste is used to replace commercial growth media in microbial fermentation processes, it becomes expedient that the implementation of the biorefinery concept becomes integrated as the microbial biomass and their metabolites will add to the product spectrum. This study demonstrates an integrated approach towards valorization of sugarcane bagasse and microbial biomass comprising of Mucor circinelloides ZSKP. A maximum reducing sugar recovery of 80.67 g/l was achieved after combining lignocellulosic pretreatment with saccharification. A low temperature, glycerol and ammonium phosphate pretreatment method was established, where glycerol pretreatment conditions were reduced to 150°C and almost a third of the initial duration. This strategy will potentially result in lower energy consumption costs, decreased release of inhibitors and lower water consumption. The ammonium phosphate-containing hydrolysate yielded 12.89 g/l of fungal biomass after fermentation to add to 20.8 g lignin from the delignification step. Sequential fermentations were performed by addition of Saccharomyces cerevisiae as a co-culture to produce biomass and ethanol. The initial aerobic M. circinelloides fermentation was followed by mixed culture anaerobic fermentation. Fermentation of M. circinelloides (3 days aerobic growth) and S. cerevisiae (5 days of anaerobic growth) generated a balanced biomass yield of 17.9 g/l and ethanol yield of 18.69 g/l. Ethanol production demonstrated effective utilization of bagasse hydrolysate and offered the possibility of concurrent production with biodiesel in this biorefinery. The mixed biomass gave a lipid yield of (3.72 g/l) and a chitosan yield of (1.84 g/l), The lignin infused glycerol plasticized chitosan biocomposite plastic had a 100% improvement in thermogravimetric properties with almost 50% more energy needed to increase the temperature of the material when compared to glycerol-only-plasticized biocomposite. The deproteination step in chitosan extraction was modified and replaced with a protein recovery step, with protein yield being improved to a maximum of 187.89 mg/g. The amino acid composition of the protein showed that it has a relatively high content of lysine making it suitable as an animal feed supplement. This study presents strategies to address feasibility concerns for production of fungal chitosan, biodiesel and bioethanol from lignocellulosic waste and realizing the goal of a circular bioeconomy.Item Effectiveness of a canteen and a behavioural worksite intervention to lower cardiometabolic risk in South Africa(2024-09) Singh, Evonne Shanita; Naicker, Ashika; Grobbelaar, HeleenBackground: Chronic lifestyle diseases like type-2 diabetes, hypertension and dyslipidaemia are modifiable; however, these non-communicable diseases (NCDs) are set to outpace communicable diseases in South Africa. The South African population has a high prevalence of NCDs, including genetic lipid disorders, diabetes and hypertension, meaning that the risk for undiagnosed conditions, like prediabetes and prehypertension, to develop to diabetes and hypertension, respectively, is high. As employees spend much of their waking hours at work, an opportunity exists to engage with this subset of the population for targeted NCD reduction goals. This study used the worksite setting as a backdrop for the implementation of targeted interventions aimed at reducing employee cardiometabolic risk. The resulting gains have economic significance for the employee, the employer, and the country. It also has direct potential to improve employees' quality of life. Aim: To measure the effectiveness of a canteen and behavioural intervention versus a canteen-only intervention among participants by evaluating the change in number of individuals reaching two or more cardiometabolic risk goals, namely reductions in blood pressure, triglycerides, and glycated haemoglobin (HbA1c) - the primary outcome, and through changes in secondary outcomes including rates of type-2 diabetes prevalence and regression to normoglycemia and changes in anthropometry, lipids, and glucose. Methodology: This two-arm randomised controlled trial (RCT) featuring a canteen and behavioural arm (CB) and a canteen-only arm (CO), was structured to provide a six-week intervention to employees at two multinational companies spread across eight worksites. Prior to randomisation, all employees were informed about the pending study through information packs distributed at employee staff meetings and during promotional visits to worksites. The information packs contained details on the study, the purpose, duration, partners, expectations, and privacy clause. A two-step screening process was followed to recruit eligible employees for the study. In step one, consenting employees from the eight worksites were screened for inclusion in the study using an eight-question survey. In step two, eligible participants from step one underwent clinical tests (HbA1c, lipids and blood pressure measurements). Consenting employees who were either prediabetic or prehypertensive completed the baseline assessments, which included anthropometry, a demographic and lifestyle survey, a dietary questionnaire, the Global Physical Activity Questionnaire (GPAQ) and the 24-hour food recall. Participants were randomised to the CB and CO treatment groups. The CO group received six weeks of canteen intervention (changes to enable a healthy food environment). In comparison, the CB group received six weeks of canteen intervention along with a behavioural intervention. The CB intervention included an intense six-week lifestyle programme based on the Diabetes Prevention Programme (DPP). The lifestyle classes were held two days per week at each worksite, with three time slots per day to facilitate employee attendance. After the intervention period, a post-test was used to repeat the clinical tests (HbA1c, lipids and blood pressure measurements), measurements for anthropometry and the 24- hour food recall. Data were analysed to assess the effectiveness of the CB and the CO intervention on cardiometabolic risk factors among prediabetic and prehypertensive employees. Diet quality was assessed through the dietary quality questionnaire (DQQ) indicators, and the Framingham Risk Score was used to calculate participants' 10-year risk for developing cardiovascular disease (CVD). Results: Out of a potential pool of 3000 employees, 797 employees participated in the screening process. After applying exclusion criteria and obtaining consent, 147 employees agreed to participate in the RCT. Of these, 72 were assigned to the CB arm, and 75 to the CO arm. In this study, success was defined by a systolic blood pressure decrease ≥ 5mmHg, a decrease in plasma triglycerides ≥0.1 mmol/L and a decrease of ≥0.5% in HbA1c. In the CO intervention arm, twenty-two participants met no improvement of cardiometabolic risk factors while 29 (19.7%) participants met one, 23 (15.6%) participants improved two; and one (0.68%) participant improved all three cardiometabolic risk factors. In the CB intervention group, 21 (14.2%) participants met no improvement of cardiometabolic risk factors, 38 (25.8%) participants improved one risk factor, 13 (8.8%) participants improved two, and none improved three cardiometabolic risk factors. To evaluate the effectiveness of the CO arm on diabetes risk, 6 (4.0%) participants met the intended intervention effect; however, 69 (46.9%) did not. From baseline (BL) to endline (EL), 2 (1.3%) participants were diagnosed as diabetic, 20 (13.6%) participants presenting with prediabetes at BL increased to 23 (15.6%) presenting with prediabetes at EL and finally, 53 (36%) participants without diabetes decreased to 50 (34%) at EL. To measure the effectiveness of a CB intervention on diabetes risk, 6 (4%) participants met the intended intervention effect however, 66 (44.8%) did not. From BL to EL, 1 (0.68%) participant was diagnosed as diabetic, 22 (14.9%) participants at BL increased to 26 (1.6%) presenting with prediabetes and finally, 49 (33.3%) participants without diabetes decreased to 45 (30.6%) at EL. To evaluate the combined effect of a CB intervention versus a CO intervention on diabetes risk, 12 (8.1%) participants met the intended intervention effect; however, 135 (95%) did not. Overall, post intervention improvements were noted for the whole group when no targeted cutoffs were applied, meaning that these participants improved their risk factors but not within projected reduction cutoffs. Conclusion: Cardiometabolic risk factors were improved for some participants using CB or CO interventions at worksites. Given that the CB and CO interventions produced similar results, the CO intervention has the potential to have a broader reach across the entire worksite, regardless of employees' health conditions, as most employees engage with the worksite food environment (canteens, board room meals, tea stations). Promoting an enabling worksite food environment is likely to encourage healthy eating habits. Unlike the CB intervention, which is more resource-intensive, the CO intervention is more feasible to implement. These results were achieved under a challenging COVID-19 lock-down period through the implementation of a 6-week intervention. There is potential to improve these outcomes outside the influence of COVID-19 and by using a longer duration intervention. Collectively, improved employee health has gains for the organisation, their employees and the country. Scope also exists to improve the effectiveness of the outcome outside of a research study and through more integrated communication and support from the different role players, including human resources, shift supervisors, management, occupational health staff and through the election of employee health champions.Item Ion doped metal oxide and its power conversion efficiency influence on Perovskite solar cells(2024-09) Reddy, Dwayne Jensen; Lazarus, Ian JosephABSTRACT Ion Doped Metal Oxide and its Influence on the Power Conversion Efficiency of Perovskite Solar Cells Dwayne Jensen Reddy Doctor of Applied Sciences This study focuses on the fabrication and characterization of Zinc-doped Titanium dioxide (ZnTiO2) as an Electron Transport Layer (ETL) in CH3NH3PbI3-based perovskite solar cells (PSCs). A one-step spin coating technique under controlled ambient conditions (relative humidity < 65%, room temperature ∼ 20oC ) for the development of PSC was applied to investigate the effects of Zn-ion doping on the structural, morphological, optical, and photovoltaic properties. Numerical simulations using SCAPS 1D were additionally performed to further investigate the influence of ion doping on the power conversion efficiency (PCE) of PSCs. Zn-doped TiO2 was successfully incorporated into the TiO2 crystal structure using the solgel technique. Characterization through X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDX) confirmed the incorporation of Zn ions. The crystallite size ranged from 19.99 to 7.1 nm, depending on the Zn ion doping concentration. XRD results also indicate the formation of a highly crystalline tetragonal perovskite (CH3NH3PbI3) phase. Fourier Transform Infrared (FTIR) spectroscopy verified the presence of the anatase phase of Zn-doped TiO2, while the formation of the adduct of Pb2 with dimethyl sulfoxide (DMSO) and methylammonium iodide (MAI) was confirmed at 1015 cm-1. Scanning Electron Microscope (SEM) images exhibited fairly smooth and uniform surface coverage for the Zn-doped TiO2 layers. The Root Mean Square (Rq) values for surface roughness showed a decrease from 26.85 nm for undoped TiO2 to 23.4 nm for the 5 mol% Zn-doped TiO2 layer. UV-Vis spectroscopy demonstrated low light transmission loss characteristics from 300 to 790 nm, with the 2 mol% Zn-doped TiO2 showing slightly improved light transmission between 550 and 800 nm. The bandgap energy of undoped and Zn-doped TiO2 ranged from 3.53 to 3.38 eV, while the perovskite layer exhibited a bandgap energy of 2.06 eV. Experimentally, an optimum PCE of 5.67% was achieved with a 2 mol% dopant concentration. However, increasing the Zn dopant to 5 mol% led to a slight deterioration in the PCE. Numerical simulations revealed that increasing the donor doping concentration in the ETL improved the conduction band alignment at the ETL and perovskite interface, resulting in a PCE of 6.17%. Optimizing the absorber acceptor doping concentration and band gap improved the PCE to 10.79%, however, created a pronounced conduction band offset at the ETL/perovskite interface. This was mitigated by introducing an interfacial layer of Cubic Silicon Carbide (3C-SiC) between the absorber and ETL to minimize the conduction band offset, ultimately achieving a PCE of 12.09%.Item Oxidative dehydrogenation of n-octane using dealuminated faujasite zeolites(2024-09) Mpotulo, Archie Sifundo; Friedrich, HB; Ndlela, SSCommercially obtained NaY was modified by a dealumination process using different solutions containing specific concentrations of citric acid, ethylenediaminetetraacetic acid disodium (EDTA-2Na), and a mixture of both EDTA-2Na and citric acid. The three prepared catalysts were then used to study the effect of dealumination on oxidative dehydrogenation (ODH) of n-octane. Dealumination was carried out to strengthen the zeolites acid sites, which will lead to an increased activity towards the oxidation of n-octane. Results from these showed that removing the framework and extra framework aluminium in the NaY zeolites increases the intrinsic acidity, which then led to increased conversion in the ODH of n-octane, with the catalyst prepared by the mixture of both EDTA-2Na and citric acid recording the highest conversion of just above 10 %. The conversion was ascribed to the removal of both the non- and framework aluminium, which leads to improved pore volumes and surface area. All the three prepared catalysts were mostly selective towards the carbon oxides (COx) products which was due to the absence of the ODH promoting metal. To induce the ODH promoting properties on the prepared catalysts (NaY[AL] for acid leaching using citric acid, NaY[CAT] for chelating agent treatment using EDTA-2Na and NaY[CT] for complex treatment using citric acid and EDTA-2Na), they were then further modified by introducing gallium using a modified ionic exchange procedure. Gallium has been shown by previous studies to be a promising ODH active metal. All the prepared catalysts were exchanged by 2 %wt of gallium which contributed to the increase of about 2 % for all the prepared catalysts when they tested were under similar ODH conditions with the first three batches of dealuminated NaY. The introduction of framework gallium also decreased side reactions such as the cyclization and cracking reactions, due to the reduction in medium to strong acid sites. The COx selectivity for the catalysts decreased from above 90 % to just below 85 %. This was not the case for the highest acidic NaY[AL], which showed no decrease in the COx selectivity. Though there was a slight improvement on the olefins selectivity after gallium introduction, COx production was still favoured by the catalysts. To mitigate this, barium, a basic metal was also introduced into the prepared Ga-NaY catalysts. Barium was also introduced using ionic exchange, and 1.5 %wt was introduced. Barium is known for inducing basic sites which facilitates the quick desorption of ODH products, leading to suppressed overoxidation. Due to subsequent ionic exchange procedures done on the catalysts, the morphology of the catalysts was altered, with the NaY zeolites losing their cubic shape and also clustering. The effect of Ba for all the catalysts was not much, as only BaGa-NaY[CT] showed a 4 % decrease in the COx activity. All the catalysts showed increased cracked products and oxygenates, but not much improvement in the olefins and aromatic products. The findings of this study showed that the behavior of the zeolite catalysts in the ODH of alkanes depends both on the physical and chemical properties of the catalyst. Acidity is a big factor when dealing with zeolites, as the activity and selectivity of the catalysts depends on the alteration of this feature. A high concentration of strong acid sites alone can activate the paraffin of interest, however Lewis acid sites induced by a reducible gallium metal are responsible for improved octene activity, selectivity and stability of the catalysts through the facilitation of coke burning on the surface of the catalyst.Item The consumption, product compliance and manufacturer insights of plant-based foods in KwaZulu-Natal(2024-09) Govender, Camilla; Naicker, Ashika; Makanjana, OnwabaBackground: The term plant-based diet focuses predominantly on the consumption of food from plants. A plant-based diet consists mainly of wholegrains, fruits, vegetables, legumes, nuts, seeds and may also include more processed food products made from these ingredients. Food is the single most powerful lever to optimise human health and environmental sustainability. A large body of work has emerged on the environmental impact of various diets. As per the findings of the Environmental Assessment and Reference Tool (EAT)-Lancet Commission, many studies have concluded that a diet rich in plant-based foods (PBFs) has improved health and also environmental benefits. This transition has led to a noteworthy increase in the demand for PBFs globally, and South Africa is no exception. Aim: This study aimed to determine the consumption, product compliance and manufacturer insights of plant-based foods in KwaZulu-Natal (KZN). Methods: This study used a mixed methods approach, namely, qualitative and quantitative research methodology. The first objective of this study was to determine the consumption of PBFs and identify barriers and facilitators influencing the adoption of plant-based diets through a consumer survey. The study's second objective was to document the scope of plant-based products in terms of availability through in-store and online observations that were available in KZN. All products were analysed to determine the scientific and regulatory compliance of plant-based products by analysing food labels according to the Foodstuffs, Cosmetic and Disinfectant Act (Act 54, 1972), R146 Regulation relating to the labelling and advertising of foodstuffs. The qualitative aspect of the study delved into the product development practices, trends and challenges of plant-based manufacturers in South Africa through key informant interviews. The adequacy of the diet among consumers (n=100) who consumed plant-based foods was assessed through two 24-hour food recalls and analysed for dietary adequacy. Results: Three hundred and eighty consumers participated in the online survey, of which 67.7% (n=259) of participants were women and 31.3% (n=120). Regarding the frequency of consumption of PBFs, 47% (n=180) of participants consumed PBFs between 2 to 3 times a week, 27.7% (n=106) of participants consumed PBFs daily, 17.2% (n=66) of participants consumed PBFs once a week, and 4.2% (n=16) of participants consumed PBFs once a month. A significant 63.4% (n=243) of participants indicated that they spend at most R60.00 on plantbased products, p<0.001. Using the binomial test to assess if any response option was selected significantly more than others, a significant number of participants (80% n=307) p<0.001, reported that they consumed PBFs for health reasons, followed by 37% (n=142) who reported that they consumed PBFs due to religious reasons. A significant 64% (n=245) and 58.5% (n=224) of participants reported that the most common format of plant-based meat alternatives that they consumed were burgers and sausages, respectively (p<0.001). The findings of this study also revealed that there are many challenges and barriers that are associated with the adoption of PBFs. This study found that 58.5% of participants (n=224) reported that PBFs were expensive (p<0.001), and 40.5% of participants (n=155) indicated that PBFs were limited and lacked variety. A comprehensive database of plant-based products (n=431) in the South African market was documented through in-store and online observations. Eighty-nine percent (n=386) of the products documented were manufactured in South Africa.. Regarding South Africa's labelling regulation, 95% (n=411) of the plant-based products complied with legislation. Key informant interviews were conducted with manufacturers to understand the market trends and constraints within the South African plant-based food sector. Key themes emerging from the key informant interviews included consumer-centric PBFs, consumer-driven plant-based trends, growth in the plant-based market, dynamic and evolving plant-based product development, challenges in PBF manufacture and marketability, insufficient government support and market-related price of PBFs. Furthermore, the adequacy of plant-based diets was analysed using the 24-hour food recall (n=92). The majority of nutrients fell below the EAR for both males and females. Both groups exhibited dietary inadequacies in specific micronutrients: vitamin D, folate, vitamin B12, and iron. Dietary inadequacy of specific micronutrients was noted for vitamin D, Folate, vitamin B12 and iron in both groups. However, there was notable carbohydrate excess intake across both groups and genders, surpassing the recommended estimate for energy. Conclusion: This study comprehensively examined the consumption patterns, product compliance, and manufacturer insights of PBFs in KZN. The findings reveal a growing interest in flexitarian diets and frequent consumption of PBFs, driven primarily by health motivations but hindered by cost and limited variety. Retail availability of PBFs in KZN is extensive, offering consumers a wide range of choices in both fresh and frozen categories, reflecting the robust state of the plant-based industry in KZN and it can be reasonably generalised to the whole country Regulatory compliance among PBFs is generally high, although small-scale manufacturers occasionally fall short of labelling standards. Manufacturer insights indicate a consumer-driven demand for PBFs that closely mimic meat products, necessitating innovation and regulatory support to stabilise this emerging market. Nutritional assessments of plant-based diets highlight a critical need for dietary supplementation to address deficiencies in essential vitamins and minerals such as B12, iron, and zinc. The study underscores the importance of nutrition education to guide consumers towards healthier food choices within plant-based diets. In conclusion, while the plant-based food sector in KZN is expanding and meeting many consumer needs, there are significant opportunities for improvement in product variety, affordability, regulatory compliance, and nutritional adequacy. Addressing these challenges through coordinated efforts among stakeholders can further enhance the adoption and benefits of plant-based diets. The conclusions drawn from this study can be reasonably generalised to metropolitan areas of the whole country.Item Increasing catalytic activity of a fructosyltransferase using site-directed mutagenesis(2024-05) Wang Fanzhi; Permaul, Kugen; Singh, SurenFructooligosaccharides (FOS) are naturally occurring metabolites that have a wide application in the food industry. They are one of the most well-studied prebiotics and have been used as an alternative sweetener to sucrose, as the modern diet demands healthier and calorie-reduced foods. FOS is commercially produced either by hydrolysis of inulin into inulin-type FOS or by sucrose transfructosylation into levantype FOS. The levan-type FOS are short-chain FOS and are produced under the catalysis of fructosyltransferase (FTase) or fructofuranosidase (FFase). In this study, FOS production was studied using a fructosyltransferase, SucC, which was originally isolated from Aspergillus niger and was functionally expressed in Pichia pastoris. The tertiary structure of SucC was determined by bioinformatics analysis and catalytic sites were verified and validated by wet and dry experiments where the amino acid residues D64, D194 and E271 were proved to form the catalytic triad. Three mutants, C66S, G273V, L313H were constructed aiming to improve the enzyme performance. Only the C66S mutant showed improved enzymatic activity which was 61% increase in specific activity. The other mutants, G273V and L313H, led to a complete loss of enzyme activity. By simulating saturated mutagenesis, tertiary structure alignment, and molecular docking, it was predicted that the C66S mutation could increase the hydrophilic environment surrounding the active site without visible changes in its structure. Two more amino acid residues (E296, H310) in addition to D64, D122, R193, D194, E271 in mutant C66S were predicted to be interacting with sucrose, and the binding energy changed from -3.65 to -4.14 kcal/mol. Subsequently, mutant C66S was constructed by site-directed mutagenesis and expressed in Pichia pastoris GS115. The purified mutant C66S showed improved enzymatic activity with a 61.3% increase in its specific activity. Its Km value was decreased by 13.5% while the kcat value increased by 21.6%. Its transfructosylation efficiency significantly improved during the initial reaction stages of FOS production. These results clearly revealed that the increase of hydrophilicity surrounding the active site enhanced the transfructosylating activities. Therefore, modification of the hydrophilic micro-environment surrounding the active site could be an alternative way to artificially evolve an enzyme’s catalytic efficiency.Item Influence of storage conditions and sample processing on viral particle recovery from untreated municipal wastewater(2024-05) Subroyen, Sueyanka; Bux, Faizal; Kumari, Sheena K.; Pillay, LeanneThe emergence and re-emergence of several epidemic and pandemic related pathogens has highlighted the need for the development and implementation of rapid and sensitive disease surveillance tools. Wastewater-based epidemiology (WBE) is one such environmental surveillance tool that has been adapted to provide a near real-time reflection of a population’s health dynamics through detecting and quantifying biomarkers from untreated wastewater. This information can be used to monitor disease progression, detect infection hotspots as well as emerging variants. The success of WBE, however, is determined by the accuracy of pathogen detection and quantification methods. Various factors, such as transportation, storage conditions, and wastewater characteristics can affect the quantification, leading to unreliable results. This study aimed at investigating the effects of storage temperatures on SARS-CoV-2 and influenza A degradation in raw wastewater samples and extracted nucleic acids. Additionally, different pre-treatment strategies for improving viral recovery from wastewater solids were also examined as part of the optimization process. Municipal wastewater influent was collected and stored at 25°C, 4°C, -20°C, and -80°C for 84 days. A control sample (spiked with attenuated viruses) was also stored under the same conditions. The viral RNA was extracted and quantified from both the samples (stored wastewater and control) every two weeks. Additionally, the physicochemical characteristics of the wastewater at different temperatures were evaluated for their possible impact on degradation. Supernatant samples and solid particles were used separately for RNA extraction and quantification to assess viral attachment to solid particles. Degradation of influenza A was observed in all samples with the highest at ±25°C in the supernatant (88.89%) and pellet (83.47%) of the wastewater influent, ±25°C in the spiked supernatant (90.69%) and 4°C in the spiked pellet (92.64%). The highest degradation of SARS CoV-2 was observed at ±25°C in the supernatant (94.1%) and pellet (92.66%) of the wastewater influent, 4°C in the spiked supernatant (95.57%) and -20°C in the spiked pellet (50.79%). The lowest degradation of SARS-CoV-2 in the spiked pellet was observed at ±25°C (44.82%) and 4°C (31.53%). This may be indicative of viral adhesion to wastewater solids. The assessment of the physicochemical characteristics indicated of changes in stored wastewater samples. Salinity, DO, pH, COD, TS, and TFS were correlated with viral degradation. pH was also found to be correlated with viral particles attaching to wastewater solids. The effect of storage temperature on stored RNA was also studied using the extracted RNA for a period of 168-days. The degradation between -20°C and -80°C was significantly different for RNA storage. The lowest degradation of SARS-CoV-2 occurred at -80°C (32.51% - wastewater influent; 33.42% - viral controls). In the case of influenza A, the lowest degradation occurred at -80°C for wastewater influent (43.28%) and -20°C for viral controls (36.02%). Statistical analysis conducted comparing storage of wastewater influent to extracted RNA indicated that degradation was higher in the wastewater samples. Additionally, to enhance viral recovery from wastewater solids, sodium pyrophosphate and ultrasonication were explored as pre-treatments strategies. SARS-CoV-2 concentrations in the supernatant were significantly increased between 3.30 - 35.65% by ultrasonication at frequencies ranging from 4 to 16 kHz, indicating that significant amounts of RNA may be attached to solid particles based on the contact time. These results highlight the importance of additional pre-treatment methods for maximizing RNA recovery from wastewater samples. The findings of this research may contribute significantly to the improvement of WBE detection methods for disease surveillance.