DUT Open Scholar:: Home

Open Scholar is the institutional repository of Durban University of Technology. As far as possible, it provides open access to the academic output of the University.

item types	authors	articles	theses

Some publishers do not permit the archiving of your article in institutional repositories if they have published it:

BASE is one of the world's most voluminous search engines especially for academic web resources:

https://www.base-search.net/

Error fetching top-level communities

Recent Submissions

Impact of Bambara groundnut protein modification on complexation behaviour with gum arabic for improved stability and functionality in food applications
(2025) Ojesanmi, Abiola Adenike; Amonsou, Eric Oscar
Protein-polysaccharides complexation has attracted considerable research interest over the past several decades, particularly regarding its role in the encapsulation of bioactive compounds, emulsion stabilization, meat mimetics, and fat replacers. However, complexes usually form within a narrow pH range characterized by weak interactions owing to a tightly packed structure and limited molecular flexibility of the native proteins. Consequently, this restricts the number of oppositely charged groups on globular proteins that can interact with polysaccharides and limits the applications of complexes in certain foods, particularly in acidic beverages. Enhancing the interactions between globular proteins and polysaccharides to achieve stable complex formation requires modifications to the protein structure, composition, and functional properties. Hence, the purpose of this study was to evaluate the influence of various protein modification methods on their physicochemical and structural properties, as well as how these structural changes affect their ability to form complexes with polysaccharides. To achieve this aim, pH-induced fractionation and ionic concentration were utilized as a protocol for extracting and structurally modifying Bambara protein prior to complexation with gum arabic. Additionally, limited trypsin hydrolysis and atmospheric cold plasma were done to modify the protein, and their impact on the stability and properties of complexes was investigated. Finally, encapsulation of riboflavin in a model beverage using Bambara protein hydrolysates (DH 5)- gum arabic soluble complex as a delivery system was determined. Response surface methodology was employed to optimise the pH-induced fractionation of Bambara protein. Thirteen experimental trials were conducted under varying extraction conditions of pH (2.0 to 9.0) and NaCl concentrations (0.0 to 0.6 M), which were considered as independent variables within a central composite design. Complexation behaviour was evaluated through turbidimetric analyses, while structural and conformational changes in fractionated proteins were examined to elucidate their interaction with gum-arabic. Bambara protein fraction obtained at pH 2.95, 0.28 M NaCl produced the most pronounced shift in pHopt (3.4) with spherical microparticles complex and 70% coacervate yield. The modification of protein-gum arabic complexation profile was corroborated by increased content of β-sheet, enriched legumin subunits, and basic amino acids of the protein fraction. Trypsin hydrolysis was done at a controlled degree of 2, 5, and 7.5 prior to complexation with gum arabic focusing on the critical pH structures formations. The hydrolysates were characterized using SEC-HPLC, zeta potential, surface hydrophobicity, and intrinsic fluorescence. Electrostatic interactions between the biopolymers were monitored through turbidimetry analysis. The stability property of the complexes was investigated using differential scanning calorimetry and rheometry. Among the hydrolysates, DH 5 produced the most stable soluble complexes over a broader pH range (7.0 - 4.3), compared to DH 2, DH 7.5, and the unhydrolyzed isolate showed enhanced binding strength and structural stability. This was evidenced by its rheological fingerprints, with DH 5 showing a more pronounced plateau value of Gʹ, indicating a stronger molecular interaction and binding strength between the hydrolysate and gum arabic. This suggests a higher degree of internal structure and makes the complex more stable. Additionally, DH 5 showed a shift in thermal transition temperature, increased negative charge, and surface hydrophobicity. Bambara protein was subjected to atmospheric cold plasma treatment (2, 5 and 10 min) prior to complexation with gum arabic. The impact of the exposure time on composition, structural changes of protein and complex behaviour was analysed. The optimum complexation, pHopt of cold plasma treated Bambara protein-gum arabic complexes significantly shifted to acidic pH following the treatment in an exposure time-dependent manner. The structural changes coincide with the observed shift from α-helix to β-sheet structure, indicating opening of the structure of protein. Crosslinking effects of cold plasma corroborated the breaking of the cross linking disulfide bonds and oxidative modification of proteins, respectively by the chemically reactive species. The variation in the protein composition was associated with a significant rise in positively charged amino acids throughout the cold plasma treatment compared to the untreated protein. The slight red shift in fluorescence intensity data of the plasma protein suggests partial unfolding of the protein structure, correlating with increased hydrophobicity and negative surface charge. The difference between the Gʹ and Gʺ values of the insoluble complex for the untreated proteins increased from < 1 log to ~ 1 log after 10 min exposure time indicating the formation of a stable network structure. The complexes formed at optimal pH (pHopt) of 3.2 and 3.0 could be useful in acidic beverages and may serve as fat replacers in low fat food products. Hence, cold plasma treatment for 5 min could be recommended for a more stable structure. The complexes formed at optimal pH (pHopt) of 3.2 and 3.0 could be useful in acidic beverages and may serve as fat replacers in low-fat food products. Hence, cold plasma treatment for 5 min could be recommended for a more stable structure. Three methods of protein modifications were employed in this study, pH fractionation in the presence of salt, limited enzymatic hydrolysis and emerging atmospheric cold plasma technology. Due to the observed structural changes following each method of modification, a choice of modification strategy depends on the intended objective. The pH fractionation with salt may be adequate for protein sources where high yield is required to produce mild acidic food products. Limited enzymatic hydrolysis and polysaccharides could be appropriate for food products with more stable and better network structure in a wider pH range while atmospheric cold plasma being a non-thermal treatment may be appropriate for heat sensitive food products and where crosslinking of the protein is required. The results of this study are uniquely differentiated by the key variables associated with each modification method, namely: exposure time in cold plasma treatment, enzyme selection in limited hydrolysis, and the range of pH and salt concentrations applied during the extraction fractionation process. This variability highlights the complexity of the research topic and suggests that further investigation is needed to fully understand the relationships between these variables. Additionally, there is a need to determine different results that could be produced when the variables are extended and their applications in other food products.
Extraction and assessing the reinforcing properties of collagen derived from fish on the mechanical properties of polymeric composite : a case of epoxy resin and polyurethane
(2025) Naidoo, Deneshree; Mokhothu, Thabang Hendrica; Onwubu, Stanley C.; Mdluli, Phumlane Selby
Epoxy resin and polyurethane are among the commonly and widely used polymeric materials. However, the high brittleness of cured epoxy polymers promotes crack propagation and limits their impact resistance. Polyurethane (PU), on the other hand, while prized for its flexibility and biocompatibility, is mainly made from petrochemicals, which are now facing environmental concerns. In addition, natural biobased PU foams reportedly have a relatively low mechanical strength. To overcome this, reinforcing epoxy and PU with toughening agents such as collagen is proposed in the literature to enhance its mechanical properties. The fish scale has tremendous unexploited potential for adding these values to waste. Particularly, the fish scale consists of a high amount of collagen, a valuable biomaterial that has found many applications in many fields, including biomedical and pharmaceutical industries. Hence, fish scale-derived collagen has emerged as a promising natural filler, offering eco-friendly, cost-effective, high-performance reinforcement for polymeric composites. The study aims to extract fish scale-derived collagen (FSC) and assess its reinforcing properties as a filler on polymeric composite with special emphasis on epoxy and polyurethane. A quantitative approach following an experimental research design was adopted in this study. The research design comprises three phases. In the first phase, collagen and milled fish scale powder were extracted from fish scale bio-waste using acid hydrolysis and ball-milling techniques, respectively. The extracted collagen was optimised by varying the extraction time, solvent concentration, solvent volume, and tris-glycine buffer. In the second phase, the extracted collagen (FSC) and milled fish scales powder (FS) were characterised with techniques such as X-ray diffraction, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy, and High-Transmission Electron Microscopy. Additionally, amino acid analysis was conducted to quantify and identify the type and amount of collagen extracted. In the third phase, epoxy (5, 10, 15, 20, and 25 wt.%) and polyurethane (0.5 and 1 wt.%), as well as laminates containing 2.5, 5, and 10 wt.%, were produced following ASTM standards. Mechanical properties, including tensile strength, elongation at break, tear resistance, and flexural strength, were evaluated according to ASTM standards for testing polymeric materials. The thermal stability of the composites was analysed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). One-way analysis of variance (ANOVA) was performed to assess differences in reinforcing properties (α = .05). The validity of the study was verified using ASTM standards, while reliability was ensured through the processes of repeatability and reproducibility. Paper 1 investigates the incorporation of milled fish scales (MFS) into ether-based polyurethane foam (PUF), revealing enhancements in mechanical properties such as tensile strength, elongation at break, and tear resistance, especially under heat-aging conditions. Paper 1 established that 0.5 wt.% FS improved tensile strength by 18.8% and tear resistance by 22% at elevated temperatures. Additionally, the composites demonstrated reduced density and enhanced flame-retardant properties, underscoring the material's suitability for lightweight and thermally resilient applications. Paper 2 evaluates fish scale collagen (FSC) as a filler, highlighting its amino acid composition and superior mechanical performance. Paper 2 established that the addition of 2.5 wt.% FSC increased tensile strength by 12.66% during heat aging, while 5 wt.% FSC enhanced elongation by 6.65% at standard temperatures. Comparative analysis with traditional fillers, such as calcium carbonate, revealed that FSC could serve as a sustainable substitute without compromising mechanical properties. However, excessive FSC content negatively impacted material flexibility and strength, indicating an optimal concentration of 2.5 wt.%. Paper 3 investigates the reinforcement of epoxy resin composites with fish scale-derived collagen (FSC) to enhance their mechanical and thermal properties. Results indicated significant improvements in tensile strength, Young's modulus, and thermal stability at lower FSC concentrations (5 and 10 wt.%), attributed to effective stress transfer and good interfacial bonding. Overall, this research highlights the potential of natural materials to enhance mechanical properties while addressing sustainability concerns. The findings contribute to the development of eco-friendly and cost-effective materials for various applications, from construction to consumer products.
Impact of anthropogenic activities affecting the water quality of Umhlathuze River in KwaZulu Natal
(2025) Bhengu, Makhosonke Simon
uMhlathuze River and its three main tributaries experiences various anthropogenic activities including agriculture, urbanization and industrialization before forming an estuary with the Indian Ocean. This River which is in the northern part of KwaZulu-Natal, South Africa supports a rapidly growing agricultural, domestic and industrial community. The comprehensive study was aimed to assess the potential impact of these anthropogenic activities over a 12-months period in 2023/4. The study showed that elementary levels were mostly within the permissible limits along uMhlathuze River, but the impact of anthropogenic activities along its tributaries was evident. Chlorides ranged between 400 and 655 mg/L along the Mholweni tributary during the rainy season while Na, Mg and Ca were also consistently above permissible limits along Mholweni and Ntambanana tributaries. Among non-toxic trace elements, only Fe exceeded its health-based precautional value during the rainy season for all sites. Trace toxic metal levels were also within permissible limits. Hg was only detected along the tributaries in the 0.017 - 0.399 µg L-1 range. The source of elevated levels of parameters along the tributaries was linked to quarry and agricultural activities and the wastewater effluents and urban runoff. The WQI values were in the 10.7 - 36.1 range implying the river water could be classified as good to excellent. The possibility of using these waters for agricultural purposes was assessed by calculating the Sodium Adsorption Ratio (SAR). The SAR results of the present study ranged from 29.5 to 76.3 which indicated that the water from the three tributaries (NTA, MH and EM) was unsuitable for irrigation. A health risk assessment identified that the river water was safe for domestic use to adults but infants and children were more likely to develop non-carcinogenic effects with HI values of 1.07 - 3.28. The ILCR values ranged between 1.20 and 9.93 indicating that consumption of unprocessed water from UMhlathuze and its tributaries will result in carcinogenic effects over one’s lifetime with infants and children affected most.
Exploring the convergence of artificial intelligence and big data analytics for resilience in humanitarian supply chains
(2024) Ahatsi, Emmanuel; Olanrewaju, Oludolapo Akanni
While there is great promise in AI-BDA applications revolutionising humanitarian operations through predictive analytics and resource optimisation, they are underexplored in disaster response contexts, especially in developing economies. The aim of this research was to evaluate current AI-BDA techniques and their effect on supply chain resilience in humanitarian settings focusing on Ghana and South Africa. The study employed an explanatory research design with a quantitative approach, analysing data from purposively sampled 200 supply chain professionals in Ghana and South Africa. Structured questionnaires measuring the implementation of four key AI-BDA techniques: Time-Series Forecasting (TSF), Early Warning Systems (EWS), Logistics Optimization (LO) and Real-time Monitoring (RTM) were used for data collection. Exploratory factor analysis and regression analysis were performed to analyse the relationship between AI-BDA techniques and supply chain resilience, controlling for organisational size and technological readiness. The results of the findings show that the AI-BDA techniques have significant effects on humanitarian supply chain’s resilience with TSF and LO having the highest predictive power with technology readiness and organisational size facilitating the adoption of AI-BDA. Moreover, the findings revealed that resource-related barriers, particularly skill gaps among staff and lack of technical expertise, represent the most significant challenges to AI-BDA adoption. The study recommends implementing a holistic AI-BDA approach that aligns with humanitarian principles. This involves a multi-faceted strategy that not only emphasizes the ethical use of AI-BDA but also prioritizes personnel capacity building through tailored training programs. These programs should focus on enhancing technical skills, such as data analysis, machine learning algorithms, and ethical considerations in data usage. By integrating these elements, organizations can ensure that AIBDA tools are utilized responsibly and effectively, ultimately leading to improved outcomes in humanitarian efforts while maintaining public trust and safeguarding individual rights.
A novel environmental framework for cleaner cement production in a cement plant
(2025) Akintayo, Busola Dorcas; Olanrewaju, Oludolapo Akanni
Meeting the Paris Agreement goal of maintaining the global temperature ‘less than 2°C and towards 1.5°C above preindustrial temperatures requires combined CO2 emissions from all countries and sectors to fall to zero and then become progressively negative by 2050–2055 (1.5°C) to 2070–2075 (2°C). Cement production is a critical component of modern infrastructure but is associated with significant environmental impacts, including high greenhouse gas (GHG) emissions, substantial energy consumption, and excessive resource usage. To address these challenges, this doctoral study proposes a novel environmental framework for cleaner cement production, structured into four integrated components: (i) Environmental Impact Assessment, (ii) Material Substitution Strategies, (iii) Optimized Production Model, and (iv) Validated Cleaner Production System. The urgency of mitigating these environmental consequences necessitates a comprehensive assessment of cement production, particularly within the South African (SA) context, where research remains limited. This study conducts a Life Cycle Assessment (LCA) of SA cement plants utilizing both midpoint and end-point approaches of the Life Cycle Impact Assessment (LCIA). A cradle-to-gate analysis of 1 kg of cement produced in a typical South Africa plant revealed that 0.993 kg CO2 eq emissions are released per kilogram of cement, with 98.8% attributed to actual CO2 emissions, significantly contributing to global warming. Furthermore, emissions of 1.6 kg of 1,4-Dichlorobenzene (1,4-DCB) eq into air and water exacerbate toxicity levels, while 0.139 kg of oil eq is linked to fossil resource scarcity. The end-point analysis highlights the potential endangerment of 55,404 human lives and 133 species annually, with a projected economic impact of R6.2 billion due to resource scarcity. To mitigate these environmental concerns, material substitution emerges as a viable strategy. This study reviews the effectiveness of various material replacement approaches, including waste and recycled materials, in reducing energy use and GHG emissions in cement production. Findings indicate that partial (1%-60%) and total material substitution can reduce energy consumption by 5.5%-40% and GHG emissions by 1%-94%. To determine the most environmentally beneficial method of cement manufacturing, an integrated life cycle assessment multi-criteria decision-making technique was employed. The LCA is employed to quantitatively evaluate the environmental effects of ten different methods of cement production across eighteen distinct categories. Meanwhile, the CRITIC weighted TOPSIS and EDAS MCDM approaches are utilized to rank the various alternatives by determining their proximity to the optimal solution. The LCA results showed that CEM III/A slag cement had lower environmental impacts than Portland cement. With a ranking score of 0.9094 and 1.7228 for EDAS and TOPSIS techniques, respectively, both MCDM identified CM10: ground granulated blast furnace slag (GGBFS) as the most recommended. Also, material substitution strategies were assessed through the valorisation of industrial waste as supplementary cementitious materials (SCMs) for sustainable concrete was carried out using two-step framework and screening over 25 waste materials, followed by a multi-criteria decision-making (MCDM) analysis using the EDAS method to rank top-performing SCMs Fly Ash, GGBFS, Silica Fume, Calcined Clay, and Metakaolin with Fly Ash emerging as the most suitable SCM. The evaluation incorporated technical parameters, pozzolanic reactivity, environmental benefits, and regulatory compliance. These findings are validated by life cycle assessment (LCA) results indicating major carbon and energy savings and highlights the importance of waste consistency, regional supply chains, and performance-based material standards in scaling SCM implementation. To systematically optimize cement production processes, this study employs Mixed-Integer Linear Programming (MILP) to model adaptive fly ash substitution strategies. The MILP model minimizes GHG emissions while maintaining production efficiency, with optimal substitution rates of 30%-40% reducing CO2 emissions by 33% and energy consumption by 19.8%. Coupled with LCA, this approach ensures a quantitative evaluation of environmental impacts, aligning industry practices with sustainability goals. In the LCA of 1 ton of cement production process with and without replacement shows that estimated amount of 80% of the impact categories reduced by 100% in the system that incorporates the partial replacement when compared to the one that doesn’t. Global warming potential and Terrestrial ecotoxicity reduces by 41% and 38% respectively. Significant reduction in CO2 as a major contributor to GW was observed. However, further analysis on TE suggests that partial replacement of clinker with fly ash (30-40%) can slightly increase the amount of some heavy chemicals (Lead, Mercury, Nickel, Vanadium and Zinc) that is emitted into the environment. In conclusion, this research provides a holistic evaluation of cement production’s environmental footprint and offers practical mitigation strategies. It underscores the urgent need for sustainable practices in cement production, highlighting material substitution as a key strategy to mitigate environmental impacts. By integrating LCA methodologies with optimization technique, the study analyses the potential of material substitution in reducing energy consumption and GHG emissions, thereby promoting a more sustainable cement industry. In conclusion, this research presents a novel environmental framework for cleaner cement production, integrating LCA, SCM screening with MCDM, MILP-based optimization, and validation through impact reduction. The framework both improves environmental performance and supports industry alignment with global sustainability goals through actionable, evidence-based strategies.