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Mémoire : Sciences : Paris, Faculté des sciences : 1832. / Titre provenant de l'écran-titre.

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 18, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Jeffre D. Firman. Includes bibliographical references.

Thesis (MTech (Business Administration))--Peninsula Technikon, 2002. / Word processed copy. Summary in English. Includes bibliographical references (leaves 80-82). Also available online.

Color formation in oils during frying is one of the most noticeable degradation reactions that occur in the frying oil. Degradation reactions cause formation of products that positively and negatively impact the nutritional and sensory qualities of both the food being fried and the frying oil. The origins of these pigment forming reactions in the oil and the factors affecting these reactions are not well understood. Assessments of the mechanisms, the components involved and external conditions affecting oil darkening were conducted. The effect of basic food ingredients, commercially sold and laboratory formulated breading and battering, preformed lipid hydroperoxides and phospholipids on color formation and oil degradation of the frying oil were investigated. Protein products, specifically whey protein, caused both the fastest darkening and thermo-oxidative deterioration of the frying oil. This breakdown was aided further through the addition of minor food materials such as glucose and amino acids as well as lipid hydroperoxides in concentrations greater than 5 % of the frying oil. Nonenzymatic browning is the main reaction causing color formation in the frying oil and utilizes carbonyls from the food product such as starches, sugars and lipid oxidation products as starting materials alongside amino groups from proteins and amino acids. Breading ingredients contributed to oil color formation due to particles from the food crust breaking off into the frying oil to further accelerate browning reactions. Increasing the temperature of the frying oil provided additional stimulus for color forming and thermo-oxidative reactions to progress at a faster rate. / xv, 184 leaves : ill. ; 29 cm

Thesis (Ph.D.) -- University of Western Sydney, 2001. / "This thesis is presented in fulfilment of the degree of Doctor of Philosophy in Science at the University of Western Sydney, Richmond, New South Wales, Australia" Bibliography : p. 145-163.

Thesis (M. Sc.)--University of Hong Kong, 1998. / Includes bibliographical references (leaves 40-42).

Στην παρούσα εργασία ασχοληθήκαμε με τα ηλεκτροτεχνικά υγρά, τόσο θεωρητικά όσο και πειραματικά. Σε θεωρητικό επίπεδο περιγράφουμε το ρόλο των μονωτικών λαδιών, τις χρήσεις τους, τις ιδιότητές τους και τους παράγοντες που τα επηρεάζουν. Σε πειραματικό επίπεδο, πραγματοποιούμε πλήθος μετρήσεων με στόχο την εξακρίβωση και την εξαγωγή συμπερασμάτων από την εφαρμογή γραμμικώς αυξανόμενης a.c. τάσης πάνω σε δύο διαφορετικά είδη μονωτικών λαδιών. / As networks of High Voltage Alternate Power can be characterized those who function in voltage higher than 1000V. Therefore, the electrological equipment which is going to be settled and function in alternate power voltage higher than 1KV is characterized as a High Voltage Equipment. The insulation of the equipment and that of the high voltage establishments is indispensable in order to maintain the potential difference between the under high voltage conductible parts. Alongside its main destination, insulation may have other roles too such as the mechanic support of the wire way, the exchange of temperature e.c.t. In the present project we dealt with the electro – technical liquids in theoretical and also in experimental level. According to the theoretical level, we described the role of the insulating oils, their uses, their attributes and the factors that affect them. According to the experimental level we accomplished a number of measurements, having as intension the verification and the deduction of conclusions coming from the application of the linearly ongoing a.c. voltage on two different kinds of insulating oils. From the aforementioned measurements we noticed the impact that the length of the gap, the temperature, even the combination of the two different insulating oils have on the tendency in breaking not only quantitavely (change of size) but also qualitatively (change of statistical attributes). For carrying out the experimental procedure we utilized the device of the High Voltages Laboratory’s electrological equipment. All measurements and also the selection of the appropriate testing prescription were done by this device, taking each time the necessary safeguards for us and for the lab’s facilities. Finally, the results were gathered in billboards and were farther analyzed according to indispensable diagrams for the deduction of conclusions. In this point is very important to mention that on those billboards is indicated the average value which refers to the tendency in breaking and that of typical variations, just for practical reasons.

During the cold reduction of steel sheet in a rolling mill, rolling oils are used for lubrication to provide the desired steel surface. Rolling oil formulations consist largely of mineral oils, glycerides and/or synthetic esters, fatty acids, emulsifiers and additives. These oils are generally used as 2-5% emulsions and will be subjected to high temperature and pressure during use. This results in chemical changes within the oil that can affect steel surface cleanliness after annealing. It is advantageous to have rolling oils that are stable but easily removed during annealing and leaving a minimal amount of residues. Thus in the field of rolling mill technology the surface quality of rolled product and stability of rolling oils are critical in the selection of lubricants. Additionally, production cost and environmental impact are also critical in the selection of lubricants. In this study, the performance of vegetable-based rolling oils was investigated by recording the FTIR spectra of the oils using Horizontal Attenuated Total Reflectance, an internal reflection accessory, before and after systematic heat treatment. Evidence was found that the vegetable-based oils degraded on heating and the spectroscopic analysis indicated that this was due to rearrangement of unsaturated components from a cis to a trans configuration. / Dissertation (MSc)--University of Pretoria, 2008. / Chemistry / unrestricted

Interesterification which can be considered as the removal of fatty acids at random from glyceride molecules, the shuffling of these acids and their replacement of the glyceride molecules, has been investigated for palm oil, palm oil fractions and palm oil mixed with other vegetable oils. The reaction has been effected at 90 C in the presence o£ sodium methoxide as a catalyst. Pancreatic lipolysis has been ernployed to check the completeness of the reaction. On complete randomisation, the fatty acid composition of the 2-position is the same as that of the whole fat either before or after interestelification. The changes in the glyceride composition resulting from interesterification have been exarnined by various standard techniques. Silver ion thin layer chromatography which separates glycerides according to their degree of unsaturation has been used extensively. Using luethyl heptadecanoate as an internal standard various component glycerides have been quantified. GLG of glycerides has also been used to study the changes in glyceride composition of fats containing a wide range of fatty acid composition. The application of thin layer chromatography, using methyl heptadecanoate as an interncll standard, has also been extended to deterrnine the esters formed during interesterification when sodium methoxide is used as a catalyst. The changes in physical properties which result from interesterification have been determined by NMR (solids fat content) and DSC (thermal behaviour). Attempts to prepare a mixture of fats and oils containing palm oil and / or palm oil fractions which simulates vanaspati have been made. Many mixtures have been subjected to interesterification and the physical properties of the products have been investigated using NMR for all the mixtures and DSC of selected mixtures. The SFC curve of each mixture has been compared with that of vana spati. useful mixtures are recognised. Some potentially Stereospecific glyceride analysis of various types of palm oils has also been carried out using Brockerhoff's method. This involves partial deacylation of the triacylglycerols, isolation of the a,B-diacylglycerols, conversion of these diacylglycerols to phospholipid derivatives and finally stereospecific hydrolysis by Phospholipase A 2 from snake venom, The possible component glycerides have then been computed as suming a i-random, z- random, 3-random distribution of the fatty acids found in each of these positions. The results have been discussed in tenus of double bond number and of carbon number: The latter has been compared with results obtained by gas chromatography of the whole oil.