The extraction yields of insoluble dietary fibre (IDF) and soluble dietary fibre (SDF) from seven whole-grain cereals (WG) ranged from 11.73% to 23.71% and 2.28% to 5.15%, respectively. Eight monomeric phenolic acids and four diferulic acids were identified and quantified in cereal alkaline extracts by reversed phase high performance liquid chromatography coupled with quadrupole - time of flight mass spectrometry. IDF alkaline extracts had significantly (p < 0.05) higher levels of total phenolic content (TPC) and DPPH radical scavenging activity than WG and SDF extracts. Corn IDF (C-IDF) extracts exhibited the highest TPC and DPPH, followed by red rice. MTT cell viability assay indicated that 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) or xanthine-xanthine oxidase (X-XO) induced cell loss can be effectively reduced by pre-incubating Caco-2BBe or FHs 74 Int cells with certain levels of C-IDF extracts. This effect was speculated to be associated with the antioxidant activity of C-IDF linked phenolic compounds.

Wastewater activated sludge is produced during the biological treatment of wastewater. After treating the sewage, the sludge is allowed to settle. Part of the settled material is returned to the treatment process as return activated sludge (RAS) and the excess is removed as waste activated sludge (WAS). The handling and disposal of the sludge are energy and capital-intensive treatments, with a significant environmental impact. This work studies the possibility to utilize RAS (an example of wastewater sludge) as a source of surface active agents. The results indicate that higly surface active materials can be extracted from RAS, and that the RAS extract has potential applications as a detergent and wood adhesive. The results also suggest that recovering a suite of products from RAS, a biological heterogenous source, can be technically feasible. An effective alkaline treatment was developed (at pH>12) that can extract up to 75% of the sludge’s organic matter, a yield higher than previously reported. Increasing the extraction pH increased the extract surface activity, which is linked to increasing the amount of higher molecular weight molecules and the presence of phospholipids. Increasing the extraction pH beyond 11 was also related to extensive cell lysis, increasing significantly the amount of recovered material and the surface activity of the extract. The alkaline extract has properties comparable to commercial detergents. Without further purification, the extract has a low surface tension (37 mN/m on average) and performs similarly to synthetic detergents. Further assessment of the RAS extract (insensitivity to pH, surface tension, interfacial tension) suggests that it may be suitable for commercial applications. The RAS extract can also be formulated into wood adhesives using glutaraldehyde as a crosslinker. The extract fraction with 10-50 kDa constituents at pH 9 achieves high adhesive shear strengths (4.5 MPa on average, at 30% relative humidity and 25°C) with 40% of wood failure. The adhesive strength of RAS-based adhesives is strongly correlated to its protein content.

In this study, firstly, bioprocess characteristics for Serine Alkaline Protease (SAP) production, using recombinant Bacillus subtilis carrying pHV1431::subC, were examined. The cell concentration, substrate concentration, SAP activity and SAP synthesis rate profiles demonstrated that the system reaches to a steady state in terms of cell growth and SAP synthesis between t=15-25 h, therefore, this time interval is appropriate to employ both metabolic flux analysis and metabolic control analysis, which apply strictly to steady state systems. After that, three separate perturbations were introduced by addition of aspartate to the production medium at a certain time of the bioprocess. The response of the cells were observed and / by comparing the changes in intracellular reactions of aspartate pathway, Asn, Thr and Ile productions were determined to be the bottlenecks in aspartate pathway and the branchpoints splitting from Asp and AspSa were identified to be weakly rigid branchpoints. Lastly, metabolic control analysis principles were applied to determine the elasticity and flux control coefficients of the simplified aspartate pathway. Aspartate formation reaction and Lys, Thr, Ile, Met producing group share the control of asparagine synthesis. The results revealed that lysine producing branch flux dominates the other branch fluxes, therefore to eliminate bottlenecks and increase SAP production, the activity of the branches leading to the formation of Asn, Thr and Ile should be increased while decreasing the activity of lysine synthesizing branch. This could be achieved either by genetic manipulation or by addition of specific inhibitors or activators to the system.

Serine alkaline protease (SAP, EC 3.4.21.62) produced by Bacillus species, that are the microbioreactors within the bioreactors, is one of the major industrial enzymes. In this study, after production by Recombinant Bacillus subtilis (BGSC-1A751), carrying pHV1431::subc gene in the complex media and separation of solids, SAP was dried by using a spray drier. Experiments were performed to investigate the stabilization of SAP during spray drying and subsequent storage. Initially, the effect of air inlet temperature of the spray drier on SAP activity was evaluated. For this purpose, SAP solutions were spray dried in the absence of any protective agents at five different air inlet temperature (700C, 900C, 1100C, 1200C, 1300C). As a result, increasing air inlet temperature lead to an increase in activity loss of SAP during drying. Thereafter, the effect of protective additives, glucose and maltodextrin (0.5%, 1%, 2% w/v), on SAP activity was investigated during spray drying. The activity loss of SAP was completely inhibited in the presence of glucose at 70, 90 and 1100C. However, the addition of maltodextrin was better than glucose for activity preservation of SAP at 1300C. Among the obtained results, 1% glucose addition was the best to preserve activity of SAP during spray drying. Then, structural change of SAP during drying was investigated. FTIR-ATR spectrum was used to evaluate the change in physical structure of the dried SAP powders in the presence of 1% glucose. From infrared images, at 900C more native-like structure for dried SAP powders was observed. In the last stage of this study storage stability of obtained SAP powders at 40C for a long period (6 months) was investigated. When considering all conditions, 0.5% maltodextrin addition was the best for stabilizing SAP powders along storage time.

Chicken dark meat has been considered as a major underutilized commodity due to the increasing demand for further processed breast meat products. Alkali aided protein extraction is an option to increase the utilization of chicken dark meat. First, the effect of pH (10.5-12.0) on alkaline extraction of chicken dark meat has been studied, and protein yield, composition, color, and TBARs of the extracted meat have been determined. Second, textural and rheological properties and water holding capacity (WHC) of alkali extracted chicken dark meat have been evaluated. The highest protein yield (94.2%) was obtained at pH 12.0. Lipid content of the extracted meat decreased by 50% compared to chicken dark meat. WHC, hardness and chewiness of extracted meat were greater at higher pH. The gel from recovered meat with added cryoprotectants showed more stability. This process may offer the possibility to use the underutilized poultry resources for preparation of functional foods. / Food Science and Technology

Geopolymers (GPs) are a special class of inorganic polymers with unique properties. Their 3-D amorphous structure and properties are often attributed to SiO2/Al2O3 molar ratios. However; contradictory results reported in literature on the structure and properties, do not conclusively support these reported findings. Furthermore, alternative processing methods are necessary for synthesizing pure geopolymers without impurities often found in precursor material. A rigorous study on chemical composition and processing parameters as well as alternative processing methods are necessary for advancing GPS in various engineering applications. The effects of H2O/(SiO2 + Al2O3) and SiO2/Al2O3 molar ratios , as well as precursor material on the density, open porosity, microstructure and the thermal and mechanical properties in K and Na activated geopolymers is investigated. X-ray diffraction, Nuclear Magnetic Resonance as well as alcohol immersion to determine density and open porosity is utilized for structural characterization. Thermogravimetric analysis and Thermomechanical analysis are used to investigate thermal behavior. Thermal conductivities and mechanical properties were measured using Thermal Constant analysis and compression testing respectively. Conclusive results demonstrate that the amount of water used to process GPs is the governing factor affecting their structure while SiO2/Al2O3 molar ratio plays no significant role. The K- and Na-activated samples have similar amounts of residual water after aging for 21 days at ambient conditions. In addition, the effects of the initial water content, SiO2/Al2O3 ratio, and alkaline activator (Na or K) on the thermal and mechanical properties of GPs, indicate that the dominant factor controlling thermal conductivity is H2O/(SiO2 + Al2O3) ratio used in processing, and to a lesser degree, the type of activation ion (Na or K). The SiO2/Al2O3 ratio did not have an effect on thermal conductivity. However, GPs compressive strengths are strongly affected by H2O/(SiO2 + Al2O3) ratio, especially at higher water ratio. At high and intermediate H2O/(SiO2 + Al2O3) ratios, liquid/solid ratio is the most important factor controlling the strength of GPs. At low H2O/(SiO2 + Al2O3) ratios, SiO2/Al2O3 ratio also plays an important role. Finally, partial geopolymer synthesis was possible using pure SiO2 and Al(OH)3 precursors, providing a possible low temperature alternative to other aluminosilicate precursors.

Metal oxide thin films are dynamic materials that have revolutionised the nature of semiconductor and electronic thin film devices. Recently, progress has stagnated in some aspects due to the increasingly complex deposition apparatus required, and the dearth of suitable precursor complexes of certain ???difficult??? metals. This thesis seeks to address both of these issues. The application of a precursor complex, Mg6(O2CNEt2)12 to the SSCVD of MgO thin films delivered the highest quality films ever reported with this technique. The resultant films were found to be of purely (111) orientation. Due to the nature of the precursor, the chemical reactions occurring at the surface during SSCVD growth result in a high growth rate, low flux environment and films of (111) orientation have been achieved without the amorphous underlayer. This finding has important implications for buffer layers in perovskite thin film devices. The unprecedented precursor chemistry has been used as a basis for the extremely high quality material produced, along with the unusual, yet beneficial structural morphology it possesses. A new range of barium complexes with single encapsulating ligands have been prepared for use in chemical vapour deposition (CVD) of BaTiO3 thin films. A novel pathway to an unprecedented class of barium carbamates is reported, and also new dianionic bis ??-ketoesterates and their barium, strontium, and calcium analogues were synthesised. High resolution mass spectrometry showed the barium bis ??-ketoesterate derivatives to be monomeric, and preliminary testing indicated some volatility in these species. Insights were gained into the likely successful pathways to building a volatile heterobimetallic precursor complex containing an alkaline earth metal. The knowledge of intimate mixing in heterobimetallic precursor complexes was extended by some novel chemistry to develop the first mixed Zn/Mg carbamato cluster complexes. These complexes were found to be excellent SSCVD precursors for ZnxMg1-xO thin films. Thin films were deposited with these precursors and exhibited a single preferred orientation, with a constant amount of magnesium throughout the bulk of the films. Investigation of the light emission properties of the films revealed significant improvements in the structural order commensurate with the incorporation of magnesium, and the formation of the ZnxMg1-xO alloy.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 5 uppsatser.

Thesis (Ph. D.)--California Institute of Technology, 1979. / Includes bibliographical references (leaves [146]-[162]).

Thesis (PhD.(Physiology)--Faculty of Health Sciences)-University of Pretoria, 2005. / Summary in English and Afrikaans. Also available on the Internet via the World Wide Web.