This work describes an investigation of the development of a Fourier Transform Infrared (FTIR) spectroscopic method for the determination of Solid Fat Index (SFI) of fats as a possible replacement of the traditional dilatometric procedure. The initial approach considered was the use of an existing FTIR analytical package which was designed to measure iodine value (IV), saponification number (SN), and cis and trans content. It was hypothesized that these measures could be related to SFI using multiple linear regression (MLR), thereby allowing the existing analytical package to simultaneously make SFI measures. It was found that there was a strong relationship between SN/cis/trans measurements and SFI, especially in sequentially hydrogenated oils. The MLR relationships, however, did not reproduce the dilatometric SFI values with sufficient accuracy in the general case, and this approach had to be abandoned. Subsequently, a partial least squares (PLS) calibration approach was investigated, relating the dilatometric SFI data directly to the spectral characteristics of the melted fats. It was found that suitable PLS calibrations could be developed for soybean and Canola oils. Based on these results, an FTIR system was programmed to determine SFI and the performance of the system validated using pre-analyzed "unknowns". It was shown that the SFI of either soybean or Canola oils could be determined to within $ pm$ 1.0 SFI. As configured, the FTIR system is capable of determining the SFI of a neat and clear, melted fat sample at 80$ sp circ$C in less than two minutes, providing four SFI values, representing the solids content at 50, 70, 80 and 92$ sp circ$F. In contrast to the standard dilatometric method, which takes over two hours to carry out, the FTIR approach provides a rapid means of determining SFI, the technique being suitable for routine quality control applications in the fats and oils industry.

Polymorphic crystal forms in food fats contribute to physical characteristics of the fats and consequently to their performance in fat based foods. In the present study the phase transitions associated with polymorphism behavior of common food fats were investigated. The polymorphism of butters, margarines, cocoa butter and cocoa butter products were determined and the effects of certain ingredients and conditions of temperature were studied. The following polymorphic forms were detected: sub-alpha, alpha, beta' , beta'3, beta' 2, beta, beta2, and beta1; however, not all forms were observed in all fats. Margarines contained beta' and beta forms depending on their fat constituents, while butter, cocoa butter, and fat blends consisted of alpha, beta' and beta; only the beta' form of butter showed a sharp melting point. Rapeseed oil exhibited alpha, beta1 and beta 2 forms, depending on the degree of hydrogenation. / DSC measurements of fat blends were correlated with viscosity index measurements from Universal Material Testing Machine (UMTM) using a single cycle, back extrusion technique. A correlation of R2 = 0.70 (p = 0.95) was obtained. Viscosity index decreased as temperature increased, suggesting a possible relationship between viscosity index and solid fat fraction. This suggests that viscosity index could be a potential indicator of food fat textural properties which are evaluated by DSC. (Abstract shortened by UMI.)

No description available.

This thesis investigates whether fats, akin to other taste stimuli, exhibit sensory properties such as mixture interactions. In order to determine gustatory, rather than tactile or olfactory effects, viscosity-controlled emulsions of deodorised oils were used as the base to which taste stimuli were incorporated and presented to a panel of trained assessors. In preliminary qualitative assessments, panellists described the 10% olive oil emulsion as saltier, stronger, fattier and having a more lingering aftertaste than the non-oil control, suggesting that oil modulates taste duration as well influencing taste intensity and/or perceived quality. Panellists were unable to rate the oil/fat taste per se with any degree of certainty hence further experiments examined the effect of oil on the perception of taste mixtures. In mixture interaction experiments, the addition of oil did not result in mixture suppression or enhancement for sweet, salty, sour or bitter while it significantly enhanced umami. To determine the locus of interaction, when MSG and oil were presented to each side of the tongue separately, the enhancement effect disappeared indicating a peripheral mechanism of interaction, similar to the attenuation of chilli burn by oil. In contrast, suprathreshold sucrose sweetness was enhanced by the contralateral presentation of oil, indicating sensory processing at a higher locus. Furthermore, the addition of oil significantly reduced bitterness in a caffeine-MSG mixture. Since earlier experiments did not indicate any interaction between oil and bitterness, the decrease in the perceived bitterness of this binary mixture is attributed to an increase in umami which is likely to have suppressed bitterness, the perceptually dominant component in this mixture. These findings suggest a gustatory role for fats in modulating the taste profile of mixtures, in particular, enhancing total taste intensity, prolonging taste duration, and enhancing umami. A taste receptor-based model of fat perception provides for an orosensory mechanism capable of signalling the arrival of the most energy-dense nutrient, essential fatty acids and fat-soluble vitamins. The chemosensory signal may also be the basis for hedonic responses with subsequent implications for intake.

Thesis (Ph. D.)--University of Wyoming, 2005. / Title from PDF title page (viewed on Nov. 5, 2007). Includes bibliographical references (p. 90-108).

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 20, 2009) Vita. Includes bibliographical references.

Thesis (PH. D.)--Columbia University, 1926. / Vita. Also issued in print.

Thesis (PH. D.)--Columbia University, 1926. / Vita. eContent provider-neutral record in process. Description based on print version record.

Thesis (M. Phil.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 208-219).

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.