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Chemopreventive Effects Of Cranberry In Association With The Alteration Of Gut Microbiota, Xiaokun Cai Nov 2016

Chemopreventive Effects Of Cranberry In Association With The Alteration Of Gut Microbiota, Xiaokun Cai

Doctoral Dissertations

Accumulating evidence showed that microbiota play important roles in colonic inflammation and inflammation-associated colon carcinogenesis. Fruits and vegetable are known to have protective effects against colon carcinogenesis. Cranberry fruit contains large amount of flavonoids, phenolic acids and dietary fiber, which has been studied for their potential chemopreventive effect from in vitro model. To better understand the effect, we studied the protective effects of whole cranberry powder against colitis in mice treated with dextran sulfate sodium (DSS) and inflammation-associated colon carcinogenesis in mic treated with azoxymethane (AOM) and DSS, and its impact on gut microbiota.

In DSS-induced colitis mice model, 1 ...


Biopolymer Electrospun Nanofiber Mats To Inactivate And Remove Bacteria, Katrina Ann Rieger Nov 2016

Biopolymer Electrospun Nanofiber Mats To Inactivate And Remove Bacteria, Katrina Ann Rieger

Doctoral Dissertations

The persistence of antibiotic resistance in bacterial pathogens remains a primary concern for immunocompromised and critically-ill hospital patients. Hospital associated infections can be deadly and reduce the successes of medical advancements, such as, cancer therapies and medical implants. Thus, it is imperative to develop materials that can (i) deliver new antibiotics with accuracy, as well as (ii) uptake pathogenic microbes. In this work, we will demonstrate that electrospun nanofiber mats offer a promising platform for both of these objectives because of their high surface-to-volume ratio, interconnected high porosity, gas permeability, and ability to contour to virtually any surface. To provide ...


Label-Free And Aptamer-Based Surface Enhanced Raman Spectroscopy For Detection Of Food Contaminants, Shintaro Pang Nov 2016

Label-Free And Aptamer-Based Surface Enhanced Raman Spectroscopy For Detection Of Food Contaminants, Shintaro Pang

Doctoral Dissertations

The development of analytical methods to detect food contaminants is a critical step for improving food safety. Surface enhanced Raman spectroscopy (SERS) is an emerging detection technology that has the potential to rapidly, accurately and sensitively detect a wide variety of food contaminants. However, SERS detection becomes a challenge in real complex matrix, such as food, since non-specific matrix signals have the potential to drown out target associated Raman peaks. In this dissertation, we focused on the development and application of label-free, aptamer-based SERS in order to improve the accuracy and specificity of target contaminant detection in food. To accomplish ...


Bacteriophage-Based Colorimetric Detection Of Escherichia Coli In Drinking Water, Juhong Chen Nov 2016

Bacteriophage-Based Colorimetric Detection Of Escherichia Coli In Drinking Water, Juhong Chen

Doctoral Dissertations

One of the major safety causes in drinking water is from the bacteria contamination, especially in developing countries and resource-limited settings. Although many of these Escherichia coli (E. coli) strains in drinking water are nonpathogenic, they sever as the indicator for bacterial contamination. And, the more widely used method to detect E. coli in drinking water is to determine the activity of β-galactosidase (β-gal), which is released by E. coli. Rapid, sensitive and inexpensive detection of E. coli in drinking water can reduce the risk of food-borne bacteria infection and stop the disease widely spreading.

In this degree research, phage-based ...


Characterizing Colorectal Cancer Cells And Their Interactions With Polymethoxyflavones By Raman Microscopy, Hua Zhang Nov 2016

Characterizing Colorectal Cancer Cells And Their Interactions With Polymethoxyflavones By Raman Microscopy, Hua Zhang

Doctoral Dissertations

Polymethoxyflavones (PMFs), especially Nobiletin (NBT) and 5-demethylnobiletin (5DN), have been widely studied and proved to have anti-cancer effects. However, their exact modes of action against cancer cells are not fully understood. Raman spectroscopy is a molecular vibrational spectroscopy can be used to measure overall biochemical function of single cells noninvasively and without adding any chemical labels. Herein, we characterized the cellular responses of human colorectal cancer HT29 and HCT116 cells, that grow on the gold coated slides, to the treatments of NBT and 5DN using Raman microscopy. Raman microscopic images obtained indicated the different modes of action of these two ...


Encapsulation Of Probiotic Microorganisms In Food-Grade Hydrogel Microbeads For Improving Long-Term Storage And Oral Delivery, Timothy W. Yeung Nov 2016

Encapsulation Of Probiotic Microorganisms In Food-Grade Hydrogel Microbeads For Improving Long-Term Storage And Oral Delivery, Timothy W. Yeung

Masters Theses

Probiotics die over time during processing, storage and digestion, resulting in reduced health benefits to the consumer. Microencapsulation of microorganisms is an effective way to improve probiotic viability by restricting cell exposure to extreme conditions through the gastrointestinal tract until release in the colon. In this work, appearance and survival of encapsulated probiotic species from two genera was explored. Lactococcus lactis and Bifidobacterium longum were suspended in calcium alginate microbeads by spraying droplets of alginate-probiotic mixture into calcium chloride solution. This produced uniformly shaped transparent microbeads with high encapsulation yield. Encapsulating Lactococcus lactis extended viability during dry room temperature storage ...


Investigate The Interactions Between Silver Nanoparticles And Spinach Leaf By Surface Enhanced Raman Spectroscopic Mapping, Zhiyun Zhang Nov 2016

Investigate The Interactions Between Silver Nanoparticles And Spinach Leaf By Surface Enhanced Raman Spectroscopic Mapping, Zhiyun Zhang

Masters Theses

Owing to their increasing application and potential toxicity, engineered nanoparticles (ENPs) have been considered as a potential agricultural contaminant that may pose unknown risk to human beings. However, many techniques require invasive and complicated sample preparation procedures to detect and characterize engineered nanomaterials in complex matrices. In the first part of this thesis, we present a non-destructive and label-free approach based on surface enhanced Raman spectroscopic (SERS) mapping technique to qualitatively detect and characterize gold nanoparticles (AuNPs), on and in spinach leaves in situ. We were able to detect the clearly enhanced signals from AuNPs at 15 to 125 nm ...


Utilizing Nutritive Sweeteners To Control Lipid Oxidation In Low Moisture Baked Goods, Samantha Vieira Nov 2016

Utilizing Nutritive Sweeteners To Control Lipid Oxidation In Low Moisture Baked Goods, Samantha Vieira

Masters Theses

In this study, we determined the effect of nutritive sweeteners at 0 to 0.50 moles/kg on lipid oxidation in a model cookie system. Confocal microscopy using Bodipy 493 as a fat soluble dye showed that the fat formed a continuous phase surrounding the starch granules regardless of sugar type. The impact of glucose concentration on lipid oxidation was monitored by lipid hydroperoxides and headspace hexanal during storage at 55°C. Low concentrations of glucose (0.09) were strong inhibitors. At equal molar concentrations, reducing sugars (glucose and fructose) inhibited lipid oxidation, greater than a two months increase in ...


Distribution Of Enterotoxigenic Clostridium Perfringens Spores In U.S. Retail Spices, Chi-An Lee Nov 2016

Distribution Of Enterotoxigenic Clostridium Perfringens Spores In U.S. Retail Spices, Chi-An Lee

Masters Theses

246 samples of bulk and packaged spices from retail stores in the western, southeastern, southern, midwestern, and northeastern areas of the U.S. were examined for the presence of Clostridium -perfringens. Isolates were checked for the presence of the lecithinase gene (cpa) and enterotoxin genes (cpe) by PCR. Enterotoxin formation during sporulation was investigated using the Oxoid Toxin Detection Kit. Forty-three confirmed isolates (from 17% of total samples) were cpa-positive. Of those, 27 were cpe-positive. Together, levels of C. perfringens spores ranged from 3.6-2400/gm. The amount of enterotoxin in cell extracts ranged from 2-16 ng/ml ...


Functionalized Electrospun Nanofibers For Food Science Applications, Minhui Dai Jul 2016

Functionalized Electrospun Nanofibers For Food Science Applications, Minhui Dai

Doctoral Dissertations

This work is separated into two individual parts. The first part demonstrates the ability to electrospin reagents into water-soluble nanofibers resulting in a stable on-chip enzyme and a microphage storage format.

1a) Polyvinylpyrrolidone (PVP) nanofibers were spun incorporating the enzyme horseradish peroxidase (HRP). Scanning electron microscopy of the spun nanofibers was used to confirm the non-woven structure with an average diameter of 155±34 nm. The HRP containing fibers were tested for a change in activity following electrospinning and during storage. A colorimetric assay was used to characterize the activity of HRP reacting with the nanofiber mats in a microtiter ...


Novel Advancements For Improving Sprout Safety, Kyle S. Landry Jul 2016

Novel Advancements For Improving Sprout Safety, Kyle S. Landry

Doctoral Dissertations

All varieties of bean sprouts (mung bean, alfalfa, broccoli, and radish) are classified as a “super-food” and are common staples for health conscious consumers. Along with the proposed health benefits, there is also an inherent risk of foodborne illness. When sprouts are cooked, there is little risk of illness. The purpose of this dissertation was to explore novel techniques to minimize or prevent the incidence of foodborne illness associated with the consumption of sprouts. Three areas were investigated: 1) the use of a biocontrol organism, 2) the use of a novel spontaneous carvacrol nanoemulsion, and 3) the influence of the ...


Synthesis And Applications Of Non-Migratory Metal Chelating Active Packaging, Maxine J. Roman Jul 2016

Synthesis And Applications Of Non-Migratory Metal Chelating Active Packaging, Maxine J. Roman

Doctoral Dissertations

Many packaged foods use synthetic chelators (e.g. ethylenediaminetetraacetic acid, EDTA) to inhibit metal promoted oxidation and/or microbial growth that may cause food spoilage. Consumer demand for foods without synthetic additives has prompted growing interest in alternative preservation methods. Our research group has previously developed non-migratory metal chelating active packaging materials by surface immobilization of polymeric chelators and demonstrated their ability to inhibit lipid oxidation in model food emulsions. The work presented in this dissertation investigates the synthesis, performance stability, and practical application of metal chelating surface modifications to optimize design of non-migratory metal chelating active packaging materials.

Metal ...


Enzyme Stabilization In Hierarchical Biocatalytic Food Packaging And Processing Materials, Dana Erin Wong Jul 2016

Enzyme Stabilization In Hierarchical Biocatalytic Food Packaging And Processing Materials, Dana Erin Wong

Doctoral Dissertations

The partnership of biocatalysts and solid support materials provides many opportunities for bioactive packaging and bioprocessing aids beneficial to the agricultural and food industries. Biocatalysis, or reactions modulated by enzymes, allows bioactive materials to assist in bringing a substrate to product. Enzymes are proteins which catalyze reactions by lowering the activation energy required to drive the production of a desired product. Enzymes are commonly utilized in food processing as catalysts with specificity in order to enhance product quality through the production of beneficial food components, and to break down undesirable components that may be harmful or may decrease product quality ...


Curcumin And Its Oxidative Degradation Products: Their Comparative Effects On Inflammation, Julia Zhu Jul 2016

Curcumin And Its Oxidative Degradation Products: Their Comparative Effects On Inflammation, Julia Zhu

Masters Theses

The anti-inflammatory agent curcumin degrades rapidly, leading to speculations that curcumin’s reported effects stem from its degradation products. Curcumin can degrade via hydrolysis, and more recently it was discovered that curcumin can degrade via oxidation at physiological pH. Additionally, bicyclopentadione is the major degradation product from this oxidation reaction. Evidence from the literature suggests that curcumin degrades primarily through oxidation. However, the biology of the oxidation products is not well characterized, and there is debate on whether oxidation intermediates or curcumin itself is more biologically active. To further elucidate the biology of the oxidation products, their effects on inflammation ...


Enzymatic Digestion Improved Bacteria Separation From Leafy Green Vegetables, Danhui Wang Jul 2016

Enzymatic Digestion Improved Bacteria Separation From Leafy Green Vegetables, Danhui Wang

Masters Theses

An effective and rapid method for the separation of bacteria from food matrix remains a bottleneck for rapid bacteria detection for food safety. Bacteria can strongly attach to the food surface or internalize within the matrix which makes their isolation extremely difficult. Traditional methods of separating bacteria from foods routinely involve stomaching, blending and shaking, however these methods may not be efficient at removing all the bacteria from complex matrices. Here, we investigate the benefits of using enzyme digestion followed by immunomagnetic separation to isolate Salmonella from spinach and lettuce. Enzymatic digestion using pectinase and cellulase was able to break ...


Influence Of Hierarchical Interfacial Assembly On Lipase Stability And Performance In Deep Eutectic Solvent, Stephanie M. Andler Jul 2016

Influence Of Hierarchical Interfacial Assembly On Lipase Stability And Performance In Deep Eutectic Solvent, Stephanie M. Andler

Masters Theses

Hierarchical systems that integrate nano- and macroscale structural elements can offer enhanced stability over traditional immobilization methods. Microparticles were synthesized using interfacial assembly of lipase with (CLMP-N) and without (CLMP) nanoparticles into a crosslinked polymeric core, to determine the impact of the highly ordered system on lipase stability in extreme environments. Kinetic analysis revealed the macrostructure significantly increases the turnover rate (kcat) following immobilization. The macrostructure also stabilized lipase at neutral and basic pH values, while the nanoparticles influenced stability under acidic pH conditions. A greener solvent, choline chloride and urea, was applied to produce sugar ester surfactants. Microparticles ...


Echerichia Coli Biofilm Formation In Musca Domestica Crops, Lufan Wang Mar 2016

Echerichia Coli Biofilm Formation In Musca Domestica Crops, Lufan Wang

Masters Theses

The house fly, Musca domestica can transmit human pathogens including Escherichia coli O157:H7 through regurgitation of ingested bacteria from the crop which is a foregut organ of house fly and stores the excess ingested nutrients. Interactions between the ingested bacteria and the crop have a direct influence on bacteria persistence, survival and ultimately fly vector competence. In this research, in situ crop vessel assay was developed to investigate bacterial growth within fly crops up to 48 hours post-ingestion. Flies were fasted for 12 h prior to feeding E. coli O157:H7 pEGFP and then fed bacteria with ...


Influence Of Inoculum Preparation Upon Sensitivity Of Common Food Borne Pathogens To Emulsion Based Antimicrobials, Dillon Sd Murray Mar 2016

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 ...


Optimization Of The Fabrication, Stability, And Performance Of Food Grade Nanoemulsions With Low And High Energy Methods, Jennifer Komaiko Mar 2016

Optimization Of The Fabrication, Stability, And Performance Of Food Grade Nanoemulsions With Low And High Energy Methods, Jennifer Komaiko

Doctoral Dissertations

There is interest in the production of emulsions by low-energy methods because no expensive equipment is required thus making emulsion formation inexpensive and simple to implement. The goal of this research is to establish the major factors that affect emulsion formation using low-energy methods and possible applications of the emulsions and nanoemulsions formed by this method. Lastly, the use of natural emulsifiers with low- and high-energy methods was investigated.

Initially, formation of nanoemulsions using isothermal low energy methods was investigated with a model system (hexadecane, Brij 30). Preliminary experiments showed that nanoemulsions could only be formed when the surfactant was ...


Fish Oil Nanoemulsions: Optimization Of Physical And Chemical Stability For Food System Applications, Rebecca M. Walker Feb 2016

Fish Oil Nanoemulsions: Optimization Of Physical And Chemical Stability For Food System Applications, Rebecca M. Walker

Masters Theses

Emulsion-based delivery systems offer many potential benefits for incorporating omega-3 oils into foods and beverages. Nanoemulsions are emulsion-based delivery systems that are gaining popularity because of their ease of preparation, small particle size, relatively high stability, high bioavailability, and production of optically transparent emulsions. Fish oil (FO) nanoemulsions are potentially more susceptible to lipid oxidation because of their high degree of lipid unsaturation, high surface area of exposed lipids, and greater light penetration. In the first study, spontaneous emulsification, a low-energy method, was used to fabricate FO nanoemulsions. The influence of surfactant-to-oil-ratio (SOR) on particle size, turbidity, and physical stability ...