Food Chemistry 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 …

Encapsulation Of Astaxanthin-Enriched Camelina Seed Oil Obtained By Ethanol-Modified Supercritical Carbon Dioxide Extraction, Liyang Xie

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Astaxanthin is a high-value carotenoid widely used in the food, feed, nutraceutical, and pharmaceutical industries. Natural sources of astaxanthin are preferable to synthetic sources. However, current sources of natural astaxanthin are limited and fall short of global demand. In addition, effective extraction and stabilization strategies are needed before the utilization of natural astaxanthin in food applications. This work investigated 1) the feasibility of ethanol-modified supercritical carbon dioxide (SC-CO2) extraction of astaxanthin from engineered camelina seed, a potential source of natural astaxanthin, and 2) the potential of an emulsion-based system to protect astaxanthin after extraction. The physical properties of the emulsion …

Thermal, Interfacial, And Application Properties Of Pea Protein Modified With High Intensity Ultrasound, Aeneas Koosis

Theses and Dissertations--Animal and Food Sciences

The overall objective of the study was to investigate different food ingredient conditions and ultrasound treatment on pea protein in terms of surface morphology and thermal characteristics. The motivation of this work was based on previous studies focusing on non-chemical physical modifications of plant proteins and the increasing demand for functional alternative proteins.

Ultrasonication time and amplitude, pH, protein concentration, and salt concentration all influenced the thermal and interfacial properties of pea protein. Ultrasound treatment altered the quaternary and tertiary structure of the storage protein and disrupted non-covalent bonds. The structural altercations and a reduction in particle size led to …

Assessment Of Physicochemical Characteristics, Thermal Stability And Release Profile Of Ascorbic Acid Microcapsules Obtained By Complex Coacervation, Michele Cristina Rodrigues Da Cruz, João Luiz Andreotti Dagostin, Camila Augusto Perussello, Maria Lúcia Masson

Articles

The aim of this study was to determine the physicochemical characteristics, thermal stability and release profile of ascorbic acid (AA) microcapsules obtained by complex coacervation. Gelatin and gum arabic were used as wall materials in concentrations of 2.5, 5.0 and 7.5 g% (w/v). The coacervate microcapsules were freeze-dried and assessed for physicochemical characteristics, thermal behavior and stability during 60 days of storage. The release profile was evaluated at different pH values (1.1, 2.2, 5.4, 7.4, 9.6 and 12). The encapsulation efficiency ranged from 27.3 to 93.8%. The microcapsules of AA presented good characteristics for application in food matrices, such as …

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 …

Relative Reactivity Of Protein And Lipid To Oxidants In Different Bi-Phasic Systems And Its Implication In Sausage Quality, Jiayi Yang

Theses and Dissertations--Animal and Food Sciences

This study investigated the progression of protein and lipid oxidation in different bi-phasic model systems: simple aqueous dispersions, liposome, and oil-in-water (O/W) emulsions. Varied concentrations of isolated pork myofibrillar protein (MFP) were mixed with free fatty acids (C18:1, C18:2, C18:3), lecithin, or vegetable oil to construct different lipid-protein dispersion systems, then subjected to hydroxyl radical stress at 4 °C. Comparison of the evolution of lipid oxidation with protein modification markers in all dispersion systems showed noteworthy attenuation of tryptophan fluorescence, protein carbonyl formation, and extensive polymerization of myosin in 2 h. This process preceded lipid oxidation which exhibited notable accumulations …