Thesis (Ph. D.)--Columbia University, 1899.

Thesis (Ph. D.)--Columbia University, 1928. / Vita. "Reprinted from the Journal of the American leather chemists association, January, 1927."

No abstract / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Lemon oil quality is affected by numerous factors including lemon variety, climate, soil type, extraction method, etc.. Therefore, quality largely depends upon the lemons' origin, and aroma profiles of oils obtained throughout the world have potential to vary considerably. This research was conducted to identify differences in the aroma profiles of lemon oil samples from a variety of sources (Argentina, Brazil, California coast, California desert, Spain, South Africa). Two sensory methods commonly used to identify such differences are descriptive analysis and gas chromatography/olfactometry (GCO). A trained sensory panel identified significant differences (p<0.05) in the aroma profiles of the nine tested lemon oils in terms of overall intensity, peel, lime, orange, and sweet aromas. While descriptive analysis is useful in identifying perceived product differences, it does not provide information regarding the chemical components responsible for product differences. GCO is an effective method for identifying a flavor system's important odorants and their odor quality, but there are numerous methods by which it may be performed. Two different GCO methods, Osme and aroma extract dilution analysis with flavor dilution (FD) factors, were used to analyze cold-pressed lemon oil, and results obtained from each method were compared. Conclusions drawn from each method regarding the most critical odorants were slightly different, and better agreement among subjects was found to be present with Osme. Upon concluding that Osme provides a less variable method of identifying critical odorants, the relationship between Osme and descriptive analysis data was examined to determine if samples were characterized similarly by both sensory methods. Considerable agreement between methods was evident. In addition, neral, geranial, limonene, linalool, and gamma-terpinene were identified as important base contributors to lemon oil aroma. / Graduation date: 1998

A study of some aspects of essential oil secretion in plants was conducted. The first part of the study involved analysis of the volatile terpenoid content and composition of leaf extracts from a range of Australian native plants by gas chromatography and mass spectrometry. Secretory structures were studied by several microscopic imaging techniques including conventional bright and dark field optical microscopy, confocal microscopy, and scanning (SEM) and transmission (TEM) electron microscopy. Three methods were employed for scanning electron microscopy. Sample material was prepared for conventional SEM by chemical fixation and rapid freeze fixation, and fresh material was imaged by environmental SEM. These methods were compared, and the images acquired by environmental SEM were invariably of a superior standard as the biological integrity of the samples was retained throughout, and the samples were free of process-induced artefacts. Several other tests were conducted and results discussed in some detail. In the final part of the study, aspects of essential oil secretion were examined by histochemical methods. The first of these was a new method based on traditional approaches to histochemistry. The monoterpene phenols thymol and carvacrol were located in glandular trichomes of Lamiaceae species by means of a colour-change reaction of the phenols with a nitrosophenol/acid reagent. The second used magnetic resonance imaging by a chemical shift selective method to locate, non invasively, the aromatic monoterpenes thymol and anethole in secretory structures in the fruit of Carum copticum (Apiaceae) and the leaves of Backhousia anisata (Myrtaceae) respectively. / Doctor of Philosophy (PhD) (Science)

The work presented in this thesis examined the effects of dietary fish oil replacement on fish innate and adaptive immune function, disease resistance tissue histopathology and fatty acid composition of lipids in peripheral blood leukocytes. Dietary trials with Atlantic salmon (Salmo salar), Sea bass (Dicentrarchus labrax), Atlantic cod (Gadus morhua) and Arctic char (Salvelinus alpinus) were conducted in which fish oil was replaced by rapeseed oil, linseed oil, olive oil, palm oil, echium oil or a mixture of these oils. A significant reduction in respiratory burst activity was most pronounced in salmon and sea bass fed high levels of rapeseed oil-containing diets. In addition, rapeseed and olive oil inclusion in the diets of salmon and sea bass significantly reduced the head kidney macrophage phagocytic capacity to engulf yeast particles. A reduction in prostaglandin E2 levels was found to be related to a reduction in macrophage respiratory burst activity in salmon fed linseed oil diets and sea bass fed a dietary blend of linseed, palm and rapeseed oils. Changes in macrophage function may be a contributing factor causing a reduction in serum lysozyme activity observed in some trials. No significant differences were detected in cumulative mortality of Atlantic salmon fed an equal blend of linseed and rapeseed oils challenged with Aeromonas salmonicida. However, resistance to Vibrio anguillarium was significantly impaired in Atlantic salmon fed a blended oil diet containing linseed, rapeseed and palm oil. The major histological difference of fish fed vegetable oil diets was the accumulation of lipid droplets in their livers. Dietary fatty acid composition significantly affected the fatty acid composition of peripheral blood leukocytes. Generally, fish fed vegetable oil diets had increased levels of oleic acid, linoleic acid and a-linolenic acid and decreased levels of eicosapentaenoic acid, docosahexaenoic acid and a lower n-3/n-6 ratio than fish fed a FO diet. In conclusion, the results from these studies suggest that farmed fish species can be cultured on diets containing vegetable oils as the added oil source. However, feeding high levels of some vegetable oils may significantly alter some immune responses in the fish, especially head kidney macrophage function, disease resistance and, in addition, may cause an increase in tissue histopathology.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Deterpenation by concentration of the flavor bearing oxygenated compounds present in Citrus Essential Oils using the column chromatographic method and the parameters affecting the adsorption of these oxygenated compounds at maximum economy versus reasonable efficiency in separation from the non-oxygenated compounds have been studied. Particular attention was given to the maximum number of adsorption-desorption-regeneration cycles that a single column charge could be subjected to before the adsorbent should be replaced. The results of this study suggested the following conditions are of importance with regard to the development of an efficient and economic operation: 1) deactivation of the silica gel column by passage of a raffinate; 2) chilling of the column and feed oil to 5°C; 3) use of minimum silica gel/oil ratio; 4) in-place regeneration of the silica gel. The results of this study also demonstrates that no rearrangements of the non-oxygenated terpenes occurred.

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published_or_final_version / Botany / Doctoral / Doctor of Philosophy