Degree Type

Thesis

Date of Award

2015

Degree Name

Master of Science

Department

Food Science and Human Nutrition

First Advisor

Nuria C. Acevedo

Abstract

Unsaturated and trans fatty acids have been proven to contribute to negative health effects such as cardiovascular diseases. There is a demand for healthier alternatives that mimic similar properties in bakery applications. Oleogels, composed of beta-sitosterol (BS) and gamma-oryzanol (GO) in vegetable oil, have recently been studied as a healthy alternative. Previous research focused on the development of a gel consisting of low concentrations of sterol mixtures. The goal of this research was to characterize the physical properties of phytosterol oleogels (POs) composed of high concentrations of sterol mixtures (10-20%) in liquid soybean oil. Samples with different BS:GO ratios were prepared and characterized. Furthermore, three different cooling rates (2, 5, and 20°C/min) were applied during the cooling process to influence the properties of POs. Appearance of POs was observed using a colorimeter. The ability of the oleogel to retain liquid oil over time was determined through oil migration analysis. The effect of sterol concentration on crystal structure was analyzed using differential interference contrast (DIC) microscopy. Solid fat content (SFC) of oleogels at various sterol concentrations was determined by proton nuclear magnetic resonance (1H NMR) spectroscopy. Additionally, the mechanical properties of oleogels were studied through small deformation rheology. Some compositions of phytosterol oleogels (POs) that had greater gelation properties displayed promising results for future use as a desirable substitute for hydrogenated oils. The sterol concentration, ratio of GO to BS, and cooling rate had a large effect on the physical properties of POs.

DOI

https://doi.org/10.31274/etd-180810-4029

Copyright Owner

Zoey Quynh Nguyen

Language

en

File Format

application/pdf

File Size

91 pages

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