Life Sciences Commons^™

Analysis Of Antioxidant Synergism And Its Mechanisms In Different Food Systems, Ipek Bayram

Doctoral Dissertations

Lipid oxidation results in off-flavors, toxic aldehydes, and co-oxidation of proteins and color compounds. Combining antioxidants to achieve synergistic interactions has been practiced for decades to improve oxidative stability. Nevertheless, synergism mechanisms have been poorly understood and rarely studied. This dissertation examines the mechanisms of antioxidant synergism in a model system with α-tocopherol (α-TOC) and myricetin (MYR). The interactions between α-tocopherol and taxifolin (TAX) were also tested because it has structural similarities to myricetin but has a higher redox potential. The first part of this research focused on the antioxidant interactions between α-tocopherol and myricetin in stripped soybean oil-in-water emulsions …

Novel Approaches For Preventing Lipid Oxidation In Emulsion-Based Food Systems, Mitchell D. Culler

Doctoral Dissertations

Consumer interest in “clean” labels has continued to be a key driver of consumer behavior and purchasing habits over the past decade. Food manufacturers are therefore eager to replace synthetic antioxidants such as ethylenediaminetetraacetic acid (EDTA) with natural alternatives, however alternative chelators that will bind iron at low pH remain elusive. Coupled with the current oil shortages and supply chain challenges that have arisen recently, there is an urgent need for innovative solutions to increase the oxidative stability of edible oils. One available strategy is diluting oils high in unsaturated fatty acids into more stable, more saturated oils, thus delaying …

Improvement Of Solubility, Stability, And Bioaccessibility Of Curcumin Using Colloidal Delivery Systems, Bingjing Zheng

Doctoral Dissertations

Curcumin is a yellow-orange crystalline substance found in certain foods (turmeric) that is claimed to exhibit a broad range of biological activities. Its application as a nutraceutical in functional foods and beverages is often limited by its relatively low solubility in aqueous media, its chemical instability, and its low bioavailability. Recent research suggests that colloidal delivery systems can overcome these hurdles and improve the efficacy and commercial value of curcumin in the food, supplement, and pharmaceutical fields. The purpose of this research was to develop colloidal delivery systems to improve the application of curcumin as a nutraceutical in foods. First, …

Application Of Flow Cytometry As Novel Technology In Studying Lipid Oxidation In Oil-In-Water Emulsions, Peilong Li

Masters Theses

The body of literature on the impact of emulsion particle size on oxidation rates is unclear. This could be because emulsions are typically polydisperse and the oxidation rate of individual droplets is impossible to discern. Flow cytometry is a technique for studying individual cells and their subpopulations using fluorescence technologies. It is possible that individual emulsion droplets could also be characterized by flow cytometry as a novel approach for studying lipid oxidation. Typical emulsion droplets are too small to be visualized by flow cytometer, so emulsions were prepared to have droplets > 2 μm; weighting agent and xanthan gum were added …

Development Of Colloids-Based Food Delivery Systems To Enhance The Beneficial Effects Of Nutraceuticals For Human Health, Zipei Zhang

Doctoral Dissertations

In current studies, hydrogel particles were formed by polysaccharides (i.e., alginate or pectin) and protein (i.e., casein or gelatin) through complex coacervation. Our results indicated that the encapsulation of protein or polyunsaturated lipid droplets nanoparticles within the hydrogel particles could improve their chemical or physical stability during storage. The lipid droplets encapsulated within the hydrogel particles could be released under simulated oral conditions, which was triggered by a pH or temperature change. The current study further fabricated the hydrogel particles (beads) using alginate or carrageenan based on an injection-gelation method. We found carrageenan beads had a relatively fragile structure that …

Tocopherol Regeneration By Phospholipids In Soybean Oil-In-Water Emulsions: Effect Of Tocopherol Homologue And Emulsifier Type, Gautam Samdani

Masters Theses

Phospholipids can regenerate oxidized tocopherols and help delay lipid oxidation. The impact of emulsifier type, tocopherol homologue and phospholipid head group on tocopherol-phospholipid interaction was investigated in this study.

Three µmol tocopherol/kg emulsion and 15.0µmol/kg emulsion of PE or PS were dissolved in oil and emulsions were prepared. Tween 20 or bovine serum albumin(BSA) was used as emulsifier and the continuous phase contained 10mM imidazole/acetate buffer at pH 7. Lipid hydroperoxides and hexanal were measured as lipid oxidation products and the lag phase was determined. With Tween 20 as the emulsifier, α and δ-tocopherol had a hexanal lag phase of …

Influence Of Inoculum Preparation Upon Sensitivity Of Common Food Borne Pathogens To Emulsion Based Antimicrobials, Dillon Sd Murray

Masters Theses

Antimicrobial optimization procedures use the most resistant bacterial culture that could be present in the food to determine the levels of treatment needed to ensure safety. These procedures usually only focus on one method of preparing these inoculums for testing despite prior research showing that the preparation of the culture can influence how the culture reacts to a treatment. In this work, planktonic cells grown in a liquid media and sessile cells grown on a similar solid media were subjected to identical emulsion based antimicrobial systems. The cultures were monitored over time and their numbers periodically enumerated. Weibullian destruction models …

Designing Novel Emulsion Performance By Controlled Hetero-Aggregation Of Mixed Biopolymer Systems, Yingyi Mao

Open Access Dissertations

The increase in obesity and overweight in many countries has led to an upsurge of interest in the development of reduced fat food products. However, the development of these products is challenging because of the many roles that fat droplets normally plays in these food products, including contributing to flavor, texture, appearance, and bioactivity. The goal of this research was to develop novel reduced-fat emulsions based on hetero-aggregation of oppositely charged food-grade colloidal particles or polymers.

Initially, lactoferrin (LF) and β-lactoglobulin (β-Lg) were selected as emulsifiers to form protein-coated fat droplets (d43 ≈ 0.38 μm) with opposite charges …