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Full-Text Articles in Life Sciences

Impact Of Surface Active Minor Components On Physicochemical Properties Of Association Colloids And Lipid Oxidation In Bulk Oil, Ketinun Kittipongpittaya Nov 2014

Impact Of Surface Active Minor Components On Physicochemical Properties Of Association Colloids And Lipid Oxidation In Bulk Oil, Ketinun Kittipongpittaya

Doctoral Dissertations

Lipid oxidation is a great concern for food manufacturers and consumers as it negatively impacts not only food quality and nutritive values of food lipids, but also consumer health. Lipid oxidation in bulk oil is impacted by chemical factors, such as, prooxidants and antioxidants, and is also related to the existence of physical structures. Bulk oils contain a variety of surface active minor components which are able to form physical structures known as association colloids. These physical structures create oil-water interfaces which seem to be an important site where lipid oxidation occurs in bulk oil. Thus, this research focused on ...


Influence Of Lipoteichoic Acid On Listeria Monocytogenes Biofilm Formation And Cellular Stress, Imelda T. Brooks Nov 2014

Influence Of Lipoteichoic Acid On Listeria Monocytogenes Biofilm Formation And Cellular Stress, Imelda T. Brooks

Doctoral Dissertations

Lipoteichoic acid (LTA) is an important polymer on the surface of Gram-positive organisms, including the foodborne, biofilm-forming pathogen Listeria monocytogenes, and is connected to the cell membrane through a glycolipid backbone. Previous results have shown the importance of LTA in cell viability and biofilm formation. The purpose of this research is to further investigate the influence of LTA in L. monocytogenes biofilm formation and how the bacterium responds to environmental stress caused by antimicrobial exposures, and a combination of low temperature and high osmolarity. We created in frame deletion mutants along the operon lmo-2555-lmo2554-lmo2553, which have been shown to reduce ...


Understanding Lipid Oxidation In Low-Moisture Food, Leann M. Barden Nov 2014

Understanding Lipid Oxidation In Low-Moisture Food, Leann M. Barden

Doctoral Dissertations

Low-moisture snacks account for much of the saturated fat in the diet, making them a key target for improving consumers’ health. However, it is not currently feasible to maintain the same shelf life when replacing saturated fats with unsaturated fats in these products.

The first study characterized the microstructure of a low-moisture cracker model system and determined the impact of iron, chelators, and free fatty acids (FFA) on lipid oxidation kinetics. Confocal microscopy showed that lipids form a continuous layer surrounding the small and/or minimally gelatinized starch granules. Lipid-starch, lipid-air, and starch-lipid-protein interfaces all existed. Oxidation studies showed a ...


Susceptibility Of Escherichia Coli O157:H7, Salmonella Enterica Sp., And Listeria Monocytogenes To Antimicrobial Mixed Micelle Delivery Systems, Chanelle N. Adams Nov 2014

Susceptibility Of Escherichia Coli O157:H7, Salmonella Enterica Sp., And Listeria Monocytogenes To Antimicrobial Mixed Micelle Delivery Systems, Chanelle N. Adams

Doctoral Dissertations

Within the food industry, there is an ever increasing demand to improve the quality of food and ensure safety from pathogenic/spoilage microorganisms. Globalization of the food industry in the 1990’s, in conjunction with the worldwide shipment of food created a need for the extension of shelf-life and enhanced maintenance of food quality (12). In the United States alone, the Centers for Disease Control and Prevention report that each year, roughly 1 in 6 Americans (or 48 million people) gets sick, 128,000 are hospitalized, and 3,000 die of foodborne diseases; this correlates to approximately $77.7 billion ...


Modification Of Gold Nanoparticles For Sers Application In Emulsion And Lipid Systems, Michael J. Driver Nov 2014

Modification Of Gold Nanoparticles For Sers Application In Emulsion And Lipid Systems, Michael J. Driver

Masters Theses

Gold nanoparticles produced using the Turkevich method were able to have their hydrophobicity modified using octanethiol in a novel method for SERS application. Both amphiliphic GNPs and hydrophobic GNPs were produced and differentiated by Raman signals. The amphiliphic GNPs were able to enhance the SERS signals of the protein emulsifier in the emulsion in situ and the hydrophobic GNPs were able to enhance the SERS signals from canola oil. Further purification of the hydrophobic GNPs proved to have higher enhancement and sensitivity, but still poor consistency which is typical of SERS. Monitoring lipid oxidation using Raman and SERS using alternative ...


Cancer Chemoprevention By Dietary Compounds Targeting Angiogenesis, Wasamon Nutakul Aug 2014

Cancer Chemoprevention By Dietary Compounds Targeting Angiogenesis, Wasamon Nutakul

Doctoral Dissertations

Cancer remains a leading cause of death worldwide. Due to angiogenesis and metastatic potency of cancer, chemotherapies are not adequate for metastatic tumor. We investigated anti-carcinogenic effects of resveratrol in comparison to those of pterostilbene in colon cancer cells. We found superior activities of pterostilbene over resveratrol in growth inhibition as well as apoptosis induction. Higher Intracellular concentration of pterostilbene could contribute to its higher potency in anti-carcinogenesis; however, both resveratrol and pterostilbene failed to inhibit colon cancer cell migration in vitro. Polymethoxylatedflavones (PMFs) found exclusively in citrus fruits have shown inhibitory effects against cancer. We investigated their anti-angiogenic activities ...


Influence Of Physical States (Crystalized Versus Solubilized) Of Bioactive Components And Oil Composition On Bioaccessibility And Bioavailability, Ziyuan Xia Aug 2014

Influence Of Physical States (Crystalized Versus Solubilized) Of Bioactive Components And Oil Composition On Bioaccessibility And Bioavailability, Ziyuan Xia

Masters Theses

Three systems were compared in the first case study: (1). pre-dissolved β-carotene nanoemulsion (d< 200nm); (2). corn oil emulsion (d< 200nm) with β-carotene crystals being added before digestion; (3). phosphate buffer saline with β-carotene being added before digestion. Oil-in-water nanoemulsions were formed by high-pressure homogenization using Tween 20 as emulsifier and corn oil as carrier oil and then they were subjected to a simulated mouth, stomach and small intestine digestion. The rate and extent of free fatty acid production in small intestine decreased in the order (2)>(1)>(3); whereas the β-carotene bioaccessibility decreased in the order (1)>>(2)>(3). In system (3), even without any fat content, there is still noticeable consumption of NaOH, which is due to the ester bonds existing in the non-ionic surfactant (Tween 20). In the second case study, we developed two comparing groups by differentiating their oil concentration (20%, 4% respectively). The bioaccessibility of the high fat group is only half of the low fat group due to the insufficient digestion of fat in the former ...


Development Of Capillary-Driven Microfludic Biosensors For Food Safety And Quality Assurance, Fei He Apr 2014

Development Of Capillary-Driven Microfludic Biosensors For Food Safety And Quality Assurance, Fei He

Doctoral Dissertations

Rapid detection technologies with high sensitivity and selectivity for pathogenic bacteria are critical in food safety and quality assurance. Traditional laboratory benchtop techniques (i.e. culture and colony counting) are time consuming and require complex sample handling. Microfluidics-based Lab-on-a-Chip (LOC) systems offer a detection alternative where all detection steps are on one portable miniaturized device. The miniaturization of rapid foodborne pathogen detection at a low cost is especially ideal for resource-limited settings or for field-use. The goal of this study was to develop a disposable miniaturized microfluidic device for on-site pathogen detection.

Capillary-driven microfluidics have been introduced in this study ...