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Title:The effects of high-intensity ultrasound of rice bran wax oleogel preparation and its effects on flaky pastry application
Author(s):Moon, Alice Ye-Eun
Advisor(s):Engeseth, Nicki J.
Department / Program:Food Science & Human Nutrition
Discipline:Food Science & Human Nutrition
Degree Granting Institution:University of Illinois at Urbana-Champaign
Trans fat
Rice bran wax
Structured lipids
Abstract:Trans-fats are associated with increased risk of various health outcomes including certain cancers, cardiovascular disease, diabetes, hypertension, and obesity. As a result, public outcry and political changes led to FDA regulatory changes to remove all partially hydrogenated oils (PHOs), which contain trans fats, from all processed food items by June 2018, in efforts to remove trans-fat consumption entirely. Trends to reduce saturated and trans-fat intake are affecting the global food market, and there is a high demand for novel alternatives for functional “solid” lipids to use in food products, while providing a nutritional benefit. The overall goal of this research was to develop oleogels to serve as a replacement for trans-fat or high saturated fat containing vegetable shortenings in flaky pastry applications. The technology of high intensity ultrasound (HIU) was utilized on oleogels formed with rice bran wax (RBX) to alter the structure of the crystalline network. The main objective of this study was to investigate the influence of HIU on the structure and stability of rice bran wax oleogels (RBXO) and its effect on the physical properties of pie crust, including flakiness, to provide an effective alternative for lipid systems with trans-fat and/or high saturated fat content. Incorporation of 5 % (w/w) RBX into canola oil (CO) resulted in self-standing oleogels. HIU was applied for 1 and 2.5 minutes at the crystallization temperature of 65oC. Oleogel characteristics were analyzed using Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), and oil binding capacity technique. Pie crust doughs were prepared with commercial shortening (CS) and RBXO with and without HIU treatments. Physical dimensional changes were analyzed using calipers. Texture analysis was conducted using a three-point bend technique. HIU treatment had an overall effect in crystal structure formation based on the results of this study. RBXO treated with 1 minute HIU shows statistical differences in melting point and an increase in polymorphism content within the crystal network, according to XRD and DSC results. The configuration of the structure did not change, yet it could be inferred that HIU increases the concentration, improving the overall functionality of RBXO. This can be confirmed in the oil binding capacity test where HIU treated RBXO were able to reduce overall phase separation compared to RBXO without HIU treatment. Pie crusts are highly dependent on the type of lipid used and the method in which they are prepared. HIU treated oleogels increased air cell density and overall lift. Pie crusts made with 1 minute HIU RBXO resulted in the most similar product to those made with CS. Both HIU treatments (1 minute and 2 minute HIU) showed significantly similar force and work to break a pie crust, indicating similar amounts of flakiness in the final product. Further subjective data must be collected, such as consumer testing and descriptive sensory testing, in order to evaluate the changes occurring in pie crusts when using RBXO with and without HIU treatments in comparison to CS made pie crusts. Further investigation is needed to understand the particular type of structural changes occurring when HIU is applied to oleogels and food applications, including pie crusts. There is great potential to apply oleogels in food products to reduce consumption of highly saturated and trans fats, while maintaining physical functional properties of hardstock lipids.
Issue Date:2017-12-15
Rights Information:Copyright 2017 Alice Moon
Date Available in IDEALS:2018-03-13
Date Deposited:2017-12

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