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Publication The Potential Health Effects of Cranberry (Vaccinium macrocarpon) Components(2024-09) Zhou, JiazhiThe influence of diet on our health extended beyond basic nutritional needs, certain components in cranberries are showing promising therapeutic potentials due to their unique biochemical properties. This dissertation explores the potential health effects of cranberry (Vaccinium macrocarpon) components, focusing particularly on their role in modulating the gut microbiota and their anti-inflammatory and anti-cancer properties. Cranberries are rich in dietary fiber and polyphenols and have been known for their prebiotic effects that potentially enhance gut health and prevent chronic diseases. This research project includes comprehensive in vitro and in vivo studies and analysis to evaluate the impact of cranberry dietary fiber and polyphenols on anti-inflammation, anti-oxidation, and anti-cancer on cell model, and their influence on gut microbiota composition in a high-fat diet (HFD)-treated mouse model. Our preliminary research indicates that cranberry components such as dietary fibers and polyphenols can significantly affect gut microbiota diversity and functionality, reducing inflammation and lowering cancer cell viability. Our in vivo study results on microbiota modulation, short-chain fatty acids (SCFA) production, and transformation of bile acids (BAs) emphasized the complex interplay between diet, microbiota, and host health, highlighting the therapeutic potential of cranberry components in managing diet-related diseases and enhancing overall metabolic health. Through the detailed studies of these interactions, our research provides valuable insights into functional foods as a natural strategy for health improvement and disease prevention.Publication Identify a Gut Bacterial Pathway for Polyphenol Hydrogenation and its Correlation with Interindividual Variations in Metabotypes(2024-09) Wu, YanyanDietary polyphenols have received tremendous attention in recent years due to cumulative evidence supporting their roles in promoting human health. Among those polyphenols, resveratrol (RES) and curcumin (CUR), have garnered substantial attention and spurred a market abundant with supplements containing these compounds for their multifaceted health benefits. However, both RES and CUR exhibit poor bioavailability as they are subjected to extensive and rapid biotransformation upon oral consumption. Multiple research has demonstrated the involvement of the gut microbiome in the hydrogenation of RES and CUR, resulting in the formation of metabolites with distinct biological effects compared to the parent compounds [23, 24]. Nevertheless, detailed studies on the bioconversion of RES and CUR by human gut bacteria, especially specific remain limited. In addition, interindividual variations in dietary component metabolism which could be related to gut microbiome diversity across populations have garnered increasing attention. A better understanding of the interindividual variability in response to diet intervention is of great significance to develop precise and adaptable nutritional recommendations that can capitalize on the biological effects of polyphenols tailored to each individual. Previous research has reported both RES and CUR display variations in significant metabolic profiling across diverse populations. However, the comprehensive understanding of the relationship between the metabotypes of RES/CUR and gut bacteria remains largely unexplored. To more deeply understand the role of the gut bacteria in RES and CUR hydrogenation as well as its association with varied metabotypes across populations, Firstly, we screened a set of human gut bacterial strains and potential gene mechanisms through in vitro experiments. We identified one gut bacterial strain (Eggerthella lenta DSM 110909) that showed the capacity to hydrogenate RES and CUR. Three candidate genes (rhe1, rhe3, and rhe3) of E. lenta DSM 110909 could be involved in the hydrogenation of RES and CUR. More interestingly, the strain-level variations in the metabolism of RES and CUR highlight the fact that gut microbial species identity is often an unreliable predictor of their metabolic functions. Secondly, we assessed the in vivo activity of E. lenta DSM 110909 in the mouse model. Our results revealed that E. lenta significantly enhanced the hydrogenation of RES, with no significant contribution to CUR hydrogenation, suggesting the distinctive dominant enzymatic processes in the hydrogenation of RES versus CUR. Thirdly, ex vivo experiments were conducted to assess the hydrogenation capacity of RES and CUR, as well as the abundance of E. lenta and three candidate genes across individuals. Interindividual variations in terms of hydronation capacity and gene abundance were observed across individuals as expected. Moreover, a strong positive correlation between the RES hydrogenation capacity and the abundance of E. lenta, along with three candidate genes was established. In contrast, such a correlation was not observed for CUR, emphasizing the necessity for exploring the dominant gut bacterial pathways responsible for CUR hydrogenation in the complex human community. Overall, our study contributed to a more profound understanding of the specific gut bacteria's role in polyphenol metabolism and its association with varied metabotypes. It lays the foundation for future targeted approaches to harness the gut microbiome for developing personalized nutritional interventions, ultimately promoting human health and well-being.Publication Utilization of Soft Matter Physics Approaches to Create Plant-based Adipose Tissue and Muscle Analogs(2024-09) Hu, XiaoyanThe negative impacts of livestock production on the environment, animal welfare, and human health have stimulated research into the development of plant-based meat analogs that look, feel, and taste like real meat. However, there are challenges in creating high-quality meat analogs using existing technologies, such as extrusion methods, which have high capital costs and energy requirements. Therefore, the purpose of this research was to explore the possibility of using soft matter physics methods to create plant-based adipose and muscle tissues with microstructures and physicochemical properties similar to those of real meat. Initially, the creation of plant-based analogs of beef adipose tissue was investigated. Microscopy, calorimetry, and rheology were used to characterize the microstructure and physicochemical properties of real and plant-based adipose tissue. The adipocytes in real adipose tissue had average diameters around 100 𝜇m and consisted of triacylglycerol-rich cells embedded in protein-rich matrices. Beef adipose tissue melted from 40 to 75 ºC, which led to significant melting, softening, and oiling off during cooking, which contributed to its desirable sensory attributes. Plant-based adipose tissue was developed using high internal phase emulsions (HIPEs) to simulate the properties of real adipose tissue. Oil-in-water emulsions were prepared with different soybean oil (60-85%) and soybean protein (0.25-3%) concentrations by homogenization. HIPEs containing 75% oil and 2% protein were found to provide appearances, textures, and stabilities somewhat like real adipose tissue. Nevertheless, the average droplet diameter (around 10 µm) in the plant-based HIPEs was considerably less than that in the real adipose tissue (around 100 µm). Moreover, the hardness of the beef adipose tissue was greater than that of the plant-based HIPEs at ambient temperature, and the real adipose tissue melted upon heating, which was attributed to the presence of fat crystals. For this reason, other emulsion technologies were employed to overcome these challenges, including adding cold-setting polysaccharides (agar) to the aqueous phase solid fats (coconut oil) to the oil phase. These strategies led to plant-based adipose tissue that more closely mimicked the texture of real adipose tissue. The potential of creating plant-based muscle tissue with a structure and texture similar to that of real meat was then explored by controlled phase separation-shearing-gelling of plant protein-polysaccharide blends. The impact of pH, salt addition, polysaccharide addition, and crosslinking with enzymes (transglutaminase) on the formation and properties of potato protein gels was examined. Potato protein was used as an example of a globular plant protein with good heat-set gelation properties. By controlling the composition, processing, and crosslinking of the protein-polysaccharide mixtures, plant-based muscle analogs could successfully be formed. Real meat products usually contain fat in the form of adipocytes, which may be present as separate tissues are dispersed throughout the biopolymer-matrix. For this reason, the impact of oil droplet concentration, size, and surface characteristics on the physicochemical properties of potato protein gels was examined. Oil droplets were coated with either a non-ionic surfactant (Tween 20) or a plant protein (patatin) to provide different surface attributes. The introduction of the oil droplets caused the protein gels to change color from mauve to off-white, due to increased light scattering. Increasing the oil droplet concentration in the emulsion gels decreased their shear modulus and Young's modulus, probably because the oil droplets were less rigid than the surrounding protein matrix. Larger oil droplet sizes had a bigger effect due to their greater deformability (lower Laplace pressure). This study showed that oil droplets significantly influence the appearance, texture, and stability of plant protein gels.Publication Study on the Interaction between Soluble Fiber from Strawberries and the Human Gut Microbiome(2024-05) Thanuphol, PongpolStrawberry is a rich source of soluble dietary fibers, mainly pectin. Previous studies have revealed the health promoting effects of whole strawberry via gut microbiota modulation possibly due to its dietary fiber content. This research delved into the multifaceted aspects of strawberry soluble fiber (SSF), aiming to unravel its prebiotic potential and its impact on gut microbial dynamics and intestinal health. Specific Aim 1 investigated the chemical composition of SSF, revealing a pectic polysaccharide structure through molecular weight distribution analysis, monosaccharide composition and FT-IR spectroscopy. Fermentation studies affirmed SSF's prebiotic potential, as evidenced by alterations in gut microbial communities and increased short-chain fatty acid (SCFA) production. Comparative analysis with citrus pectin suggested SSF's promising role in improving gut microbial profiles. Specific Aim 2 focused on isolating and characterizing human gut bacteria capable of fermenting SSF. Three distinct Bacteroides species, B. vulgatus, B. faecis, and B. xylanisolvens, exhibited enhanced growth in response to SSF, emphasizing its prebiotic properties. The study highlighted the potential synergy between SSF and specific bacterial strains, paving the way for a deeper understanding of SSF's positive impacts on gut health. In Specific Aim 3, an animal study explored the interplay between SSF, gut microbiota, and intestinal structure. SSF supplementation, alongside citrus pectin, demonstrates dose-dependent effects on jejunal villus height, jejunal V/C ratio, and SCFA profiles. Bile acid analysis revealed changes in primary and secondary bile acids, emphasizing the influence of SSF on host metabolism. Gut microbial community analysis at various taxonomic levels provided insights into the intricate relationships governing gut microbiota dynamics in response to SSF and bacterial treatments. Overall, this comprehensive investigation unveiled SSF as a potential food ingredient with prebiotic properties, offering valuable insights into its chemical composition, microbial modulation effects, and impacts on intestinal health. Further research regarding molecular mechanism of action is essential to solidify SSF's role as a prebiotic and its potential applications in promoting gut health.Publication EXPLORING THE GASTROINTESTINAL HEALTH-PROMOTING POTENTIAL OF A HUMAN GUT BACTERIAL STRAIN(2024-05) Sun, YukunThere has been a growing interest in the field of gut health, largely attributed to the rising prevalence of Inflammatory Bowel Disease (IBD) and Colorectal Cancer (CRC). When addressing gut health, the key role of the gut microbiota cannot be underestimated, it stands as a critical element in maintaining gastrointestinal homeostasis. Among the most prevalent and accessible methods for modulating the gut microbiota is the incorporation of probiotics into one’s diet. These beneficial microorganisms find extensive application in a variety of food products, including various fermented products, and dietary supplements. However, despite the multitude of microbial species colonized in the human body, only a select few have been designated for use as probiotics. The genus Bifidobacterium is one of the genera that has been widely used in functional foods for health promotion as probiotics due to its beneficial effects on human health, especially in the gastrointestinal tract (GIT). In this dissertation, we characterize the gastrointestinal health-promoting potential of a potential probiotic strain Bifidobacterium pseudocatenulatum UMA14, isolated from a healthy male adult. With the comparison with 11 commercial strains, UMA14 secretion performed significantly better effects on the inhibition of inflammatory response in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and the decreases of the cell viabilities in HCT 116 cancer cell line. Moreover, oral administration of bacteria UMA14 alleviated the severity of colonic inflammation in dextran sulfate sodium (DSS)-treated colitis mice, which was evidenced by decreased disease activity index (DAI) and enhanced structural integrity of the colon. The 16S rRNA gene sequencing result illustrated that the UMA14 alleviated DSS-induced gut microbiota dysbiosis, and enriched the diversity of gut microbiota, accompanied by the modulated bile acids, short-chain fatty acid (SCFA), other metabolites, and gene expression levels of inflammatory factors. The metabolomics analysis demonstrated that the arachidonic acid (ARA) metabolic pathway is closely related to this colitis-suppressing process. Overall, our results demonstrated the potential gastrointestinal health-promoting properties of Bifidobacterium pseudocatenulatum UMA14 on both in vitro and in vivo models, which provided a solid foundation for further development of a novel anti-inflammatory probiotic and opened new possibilities for the treatment of IBD.Publication INVESTIGATE THE IMPACT OF ADJUVANTS ON PESTICIDE PERSISTENCE AND DEVELOP AN EFFECTIVE STRATEGY TO REDUCE PESTICIDE RESIDUES ON FRESH PRODUCE(2024-05) Du, XinyiUnderstanding the effects of adjuvants on pesticide persistence and penetration in fresh produce is of great significance for optimizing pesticide formulations, managing residues, and ensuring food safety. This study investigated the impact of some common adjuvant products, non-ionic surfactants alkylphenol ethoxylates (APEOs), and crop oil concentrate (COC), on the behavior of systemic and non-systemic pesticide active ingredients (AIs). Surface-enhanced Raman spectroscopy (SERS) combined with liquid chromatography with tandem mass spectrometry (LC-MS/MS) were utilized for accurate analysis of pesticide residue in postharvest spinach leaves and apples. Results indicated that APEOs significantly enhanced the persistence and penetration depth of systemic thiabendazole in both apples and spinach. In contrast, APEOs had negligible impact on the non-systemic phosmet. Furthermore, COC considerably facilitated the penetration of systemic carbaryl in apples but did not aid the persistence of non-systemic thiram when subjected to baking soda soaking. Furthermore, the study developed an effective green washing strategy using common household ingredients to reduce pesticide residues on fresh produce effectively and safely, compared with the washing strategy using a commercial agent. This project is of great significance for providing potent guidance for applying pesticides while minimizing the residues in production agriculture and thus lowering the safety risk to humans.Publication CONTROL OF SALMONELLA IN DRY ENVIRONMENTS VIA OIL-BASED CLEANING AND SANITATION(2024-05) Chuang, ShihyuContamination with Salmonella spp. is ubiquitous across dry environments due to the persistence of this organism during desiccation and the subsequently induced cross-tolerance. For low-moisture food manufacturing, wet cleaning is limited owing to the need for a complete dry-out and that moisture trapped within surface pits and crevices breeds pathogens. Likewise, alcohol wipes are prioritized over bulk-water systems to sanitize the equipment based upon quick evaporation. Alcohol-based systems, however, must be applied only when the machinery is turned off and allowed for cooldown due to flammability, introducing downtime. This work explored the use of oil as a delivery system for organic acids to inactivate foodborne bacterial pathogens desiccated on stainless steel. A controlled, low level of water dispersion (0.3% v/v) enhanced the bactericidal efficacy of acetic acid-acidified oil by a pronounced margin. Desiccated Salmonella was reduced by greater than 6.5 log after treatment with acidified water-in-oil (W/O) emulsion (200 mM acetic acid) for 20 min at room temperature (20−22 °C), or for 15 min at 45 °C. The dispersed water droplets allowed the partitioning of acetic acid and created imbalanced vapor pressure at the cell-oil interface, prompting osmotic downshift and lysing the cells with a damaged membrane. A decrease in Salmonella membrane viscosity was evident with increasing temperature, effectively allowing extracellular compounds to permeate into the cells. A tubing system loaded with inoculated peanut butter was used to evaluate a dry cleaning and sanitation procedure involving flushing with fresh oil under laminar flow, followed by holding with the formulated antimicrobial oils. System decontamination was achieved by a 3.6-min oil flush and a 30-min contact with acidified W/O emulsion at 60 °C. Enterococcus faecium NRRL B-2354 may be used as a Salmonella surrogate to validate such a process based upon the more conservative inactivation kinetics consistently exhibited by the former. Furthermore, Salmonella biofilms grown using the CDC Biofilm Reactor were reduced to a level undetectable by enrichment after a 60-min contact with acidified W/O emulsion at 60 °C, regardless of the biofilm matrix hydration levels. The established oil-based approach allows a paradigm shift precluding traditional wet cleaning and flammable alcohol sanitizers.Publication CANORHABDITIS ELEGANS: A MODEL TO DETERMINE HEALTHY AGING(2024-05) Cho, JunhyoAging is an inevitable time-dependent process involving degenerative physiological alterations in tissues and organs that increase the susceptibility to various chronic diseases and eventually lead to death. The aging studies focus on lifespan, but more recently research on healthspan to improve the quality of life during aging has emerged. Aging is a common process for all animal species; however, due to the limitation of time in aging study, Caenorhabditis elegans,a eukaryotic, multi-organ nematode, is considered the premier choice model system for the study of aging. Like humans, C. elegans expresses degenerative muscle functions due to aging. This study determined the lifespan regulation effect of natural compounds and pharmaceutical compound in C. elegans. Coffee is one of the most widely consumed beverages and is known to have many health benefits. Our previous study reported that kahweol, a diterpene found in coffee, reduced fat accumulation by reducing food intake in Caenorhabditis elegans. Kahweol significantly extended the lifespan of wild-type C. elegans. However, kahweol increased the lifespan of the eat-2 null mutant that has a reduced food intake phenotype, suggesting that kahweol extends lifespan independent of reduced food intake. Therefore, we further determine the target of kahweol on lifespan extension. Kahweol had no effects on the lifespan of both daf-2 (the homolog of insulin/insulin-like growth factor-1 receptor) and daf-16 (the homolog of Forkhead box O transcription factor and a major downstream target of daf-2) null mutants, suggesting kahweol extended lifespan via insulin/insulin-like growth factor-1 signaling pathway. In addition, kahweol failed to extend lifespan in tub-1 (the homolog of TUB bipartite transcription factor) and aak-2 (the homolog of AMP-activated protein kinase) null mutants, suggesting these roles on kahweol’s effect on lifespan. However, the treatment of kahweol increased the lifespan in sir-2.1 (the homolog of NAD-dependent deacetylase sirtuin-1) and skn-1(the homolog of nuclear factor erythroid 2-related factor 2) null mutants over the control, suggesting independent functions of these genes on kahweol’s lifespan extension. Cannabis, also known as marijuana, has been resurging its interest for its potential medical properties as well as recreational usages. Cannabinoid receptor type 1 and 2 (CB1R and CB2R, respectively) were discovered as the target of the main psychotropic effects of marijuana, which is a part of the endocannabinoid system, composed of endocannabinoids, cannabinoid receptors, and their metabolic enzymes. It has been reported that CB1R contributes to obesity and its metabolic consequences, and CB1R antagonism in mice reversed age-related insulin resistance and metabolic dysregulations. Treatment of ACEA (arachidonyl-2’-chloroethylamide, a highly selective agonist of cannabinoid receptor type 1) significantly reduced lifespan, 13% over the control, p=0.0032. Meanwhile, treatment ofrimonabant (a selective inverse agonist of cannabinoid receptor type 1) extended lifespan, 15% increase over the control, p=0.042. Treatment of either ACEA and rimonabant did not show significant effect in daf-2, daf-16, aak-1, sir-2.1, and skn-1 null mutants. However, only rimonabant did not show lifespan extension effect in aak-2 null mutant. We further evaluated various markers of muscle functions and determined that bending or pharyngeal pumping rate can be used to represent the healthiness of nematodes. The quantified health-related metrics data were applied to set up a method to determine the healthiness of C. elegans.Publication Evolutionary dynamics of Listeria monocytogenes: Insights into Genomic Variability and Stress tolerance(2024-05) Bechtel, Tyler DPublication Development of Structured Delivery Systems Using Nanolaminated Biopolymer Layers(2009-09) Cho, Young-HeeThe objectives of this study were to carry out research to better understand of the formation, stability and properties of multilayer emulsions containing nano-laminated biopolymer coatings, and to utilize this information to develop food-grade delivery systems. The effect of various preparation parameters on the formation and stability of multilayer emulsions was investigated: droplet concentration; mean droplet diameter; droplet charge; biopolymer concentration. β-lactoglobulin (β-Lg) stabilized emulsions (0.5 – 10 wt% oil) containing different pectin concentrations (0 to 0.5 wt%) were prepared at pH 7 (where lipid droplets and pectin molecules were both anionic) and pH 3.5 (where lipid droplets were cationic and pectin molecules anionic) and “stability maps” were constructed. At pH 3.5, pectin adsorbed to the droplet surfaces, and the emulsions were unstable to bridging flocculation at intermediate pectin concentrations and unstable to depletion flocculation at high pectin concentrations. At certain droplet and pectin concentrations stable multilayer emulsions could be formed consisting of protein-coated lipid droplets surrounded by a pectin layer. An in situ electro-acoustic (EA) technique was introduced to monitor the adsorption of charged polysaccharides onto oppositely charged protein-coated lipid droplets. The possibility of controlling interfacial and functional characteristics of multilayer emulsions by using mixed polysaccharides (pectin/carrageenan or pectin/gum arabic) was then examined. Emulsions containing different types of polysaccharides had different interfacial characteristics and aggregation stabilities: carrageenan had the highest charge density and affinity for the protein-coated lipid droplets, but gave the poorest emulsion stability. The possibility of assembling protein-rich coatings around lipid droplets was examined using the electrostatic deposition method, with the aim of producing emulsions with novel functionality. Protein-rich biopolymer coatings consisting of β-Lg and pectin were formed around lipid droplets using the electrostatic deposition method. The composite particles formed had relatively small diameters (d < 500 nm) and were stable to gravitational separation. They also remained stable after they were heated above the thermal denaturation temperature of the globular protein and had better stability to aggregation at high salt concentrations (50 – 200 mM NaCl) than conventional emulsions stabilized by only protein. The effect of a polysaccharide coating on the displacement of adsorbed globular proteins by non-ionic surfactants from lipid droplet surfaces was examined to simulate situations where competitive adsorption occurs. Oil-in-water emulsions stabilized by β- Lg were prepared containing either no pectin (1º emulsions) or different amounts of pectin (2º emulsions). At pH 3.5, where pectin forms a coating around the β-Lg stabilized lipid droplets, the amount of desorbed protein was much less for the 2º emulsion (3%) than for the 1º emulsion (39%), which indicated that the pectin coating inhibited protein desorption by surface active agents. Knowledge gained from this research will provide guidelines for rationally designing emulsion-based delivery systems that are resistant to environmental stresses or with controlled release properties. These delivery systems could be used to encapsulate, protect and release functional components in various industrial products, such as foods, pharmaceuticals, cosmetics, and personal care products.Publication Designing Novel Emulsion Performance by Controlled Hetero-Aggregation of Mixed Biopolymer Systems(2013-09) Mao, YingyiThe 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 at neutral pH: pKaβ-Lg ≈ 5 < pH 7 < pKaLF ≈ 8.5. Droplet aggregation occurred when these two emulsions were mixed together due to electrostatic attraction. The structural organization of the droplets in these mixed emulsions depended on the positive-to-negative particle ratio, particle concentration, pH, ionic strength, and temperature. The nature of the structures formed influenced the rheology, stability, and appearance of the mixed emulsions, which enabled some control over emulsion functionality. The largest microclusters were formed at particle ratios of 40% LF-coated and 60% β-Lg-coated fat droplets, which led to mixed emulsions with the highest apparent viscosity or gel strength. At low total particle concentrations (0.1%), there was a relatively large distance between microclusters and the mixed emulsions were fluid. At high particle concentrations (>20%), a three-dimensional network of aggregated droplets formed that led to gel-like or paste-like properties. The influence of environmental stresses on the physicochemical stability of the microclusters formed by hetero-aggregation was investigated: pH (2-9); ionic strength (0-400 mM NaCl); and temperature (30-90 ºC). Large microclusters were obtained at pH 7 (d43 ≈ 10 μm) with the absence of salt at room temperature. More acidic (< pH 6) or alkaline (> pH 8.5) solutions resulted in smaller aggregates by minimizing the electrostatic attraction between the protein-coated fat droplets. Microclusters dissociated upon addition of intermediate levels of salt, which was attributed to screening of attractive electrostatic interactions. Heating the microclusters above the thermal denaturation temperature of the proteins led to an increase in gel-strength, which was attributed to increased hydrophobic attraction. The influence of hetero-aggregation of lipid droplets on their potential biological fate was studied using a simulated gastrointestinal tract (GIT). Results showed that the mixed emulsions had high viscosity in the simulated oral environment but exhibited similar rheological properties and particle characteristics as single-protein emulsions in the simulated gastric and small intestinal tract regions. The mixed emulsions also had similar lipid digestion rates in the simulated small intestine as single-protein emulsions suggesting that they could be used as delivery systems for bioactive lipophilic compounds in reduced fat food products. The possibility of using more practical food ingredients to promote heteroaggregation system was also examined. Whey protein isolate (positive) and modified starch (negative) were selected as building blocks due to their opposite charges at pH 3.5. The largest aggregates and highest viscosities occurred at a particle ratio of 70% MS and 30% WPI, which was attributed to strong electrostatic attraction between the oppositely charged droplets. Particle aggregation and viscosity decreased when the pH was changed to reduce the electrostatic attraction between the droplets. Finally, the influence of interfacial properties on the chemical stability of bioactive components in emulsion-based delivery systems containing mixed proteins was studied. Lactoferrin (LF: pI ≈ 8) and β-lactoglobulin (β-Lg: pI ≈ 5) were selected to engineer the interfacial properties. Interfaces with different structures were formed: LF only; β-Lg only; LF-β-Lg (laminated); β-Lg -LF (laminated); β-Lg /LF (mixed). The influence of pH, ionic strength, and temperature on the physical stability of β-caroteneenriched emulsions was then investigated. LF- emulsions were stable to the pH change from 2 to 9 but the aggregation was occurred in intermediate pH for other emulsions. β- Lg- emulsions aggregated at low salt concentration (≥ 50mM NaCl), however other emulsions were stable (0 - 300mM NaCl). β-Lg /LF (mixed) emulsions were unstable to heating (≥ 60 ºC), but all other emulsions were stable (30 to 90 ºC). Color fading due to β-carotene degradation occurred relatively quickly in β-Lg-emulsions (37 ºC), but was considerably lower in all other emulsions, which was attributed to the ability of LF to bind iron or interact with β-carotene. Overall, this study shows that hetero-aggregation may be a viable method of creating novel structures and rheological properties that could be used in the food industry.Publication Inhibition of Lung Carcinogenesis by Polymethoxyflavones(2013-09) Charoensinphon, NoppawatLung cancer is the leading cause of cancer-related death worldwide. Exclusively found in citrus peels, the inhibitory effects of polymethoxyflavones (PMFs) on 3 human non-small cell lung cancer cells have been investigated. Results showed that monodemethylated PMFs at 5-position potently inhibited lung cancer cells than those of their permethoxylated counterparts. The inhibition of cancer cells caused by monodemethylated PMFs was associated with both extensive cell cycle arrest and apoptosis as a result of modulation of key oncogenic signaling proteins. Treatment with different bioactive compounds in combination may enhance inhibitory effects on lung cancer due to their synergistic interaction among these agents. Results showed that both nobiletin/atorvastatin (NBT/ATST) and tangeretin/atorvastatin (TAN/ATST) co-treatments at low doses exerted strong synergy as confirmed by isobologram analysis, and also produced much stronger inhibitory effects on lung cancer cells in comparison to those produced by NBT, TAN, or ATST alone at higher doses. Flow cytometry analysis showed both NBT/ATST and TAN/ATST co-treatments significantly induced cell cycle arrest and apoptosis, and these molecular events were involved with prenylation of RhoA which subsequently resulted in alteration of key signaling proteins. Supplementation of mevalonate or geranylgeranyl pyrophosphate significantly counteracted the effects caused by NBT/ATST. Inhibitory effects of metabolites of PMFs against lung cancer cells were significantly stronger than those produced by their parental compounds. Treatments of PMFs significantly inhibited lung tumorsphere formation and aldehyde dehydrogenase bright cells implicating the potential utilization of these compounds to target lung cancer stem cells.Publication Surface Modification of Food Contact Materials for Processing and Packaging Applications(2013-05) Barish, Jeffrey AlanThis body of work investigates various techniques for the surface modification of food contact materials for use in food packaging and processing applications. Nanoscale changes to the surface of polymeric food packaging materials enables changes in adhesion, wettability, printability, chemical functionality, and bioactivity, while maintaining desirable bulk properties. Polymer surface modification is used in applications such as antimicrobial or non-fouling materials, biosensors, and active packaging. Non-migratory active packagings, in which bioactive components are tethered to the package, offer the potential to reduce the need for additives in food products while maintaining safety and quality. A challenge in developing non-migratory active packaging materials is the loss of biomolecular activity that can occur when biomolecules are immobilized. Polyethylene glycol (PEG), a biocompatible polymer, is grafted from the surface of ozone treated low-density polyethylene (LDPE) resulting in a surface functionalized polyethylene to which a range of amine-terminated bioactive molecules can be immobilized. The grafting of PEG onto the surface of polymer packaging films is accomplished by free radical graft polymerization, and to covalently link an amine-terminated molecule to the PEG tether, demonstrating that amine-terminated bioactive compounds (such as peptides, enzymes, and some antimicrobials) can be immobilized onto PEG-grafted LDPE in the development of non-migratory active packaging. Fouling on food contact surfaces during food processing has a significant impact on operating efficiency and can promote biofilm development. Processing raw milk on plate heat exchangers results in significant fouling of proteins as well as minerals, and is exacerbated by the wall heating effect. An electroless nickel coating is co-deposited with polytetrafluoroethylene onto stainless steel to test its ability to resist fouling on a pilot plant scale plate heat exchanger. Further work was performed to test the stability of non-fouling material after extended exposure to an alkali detergent or acid sanitizer formulated for clean-in-place procedures in dairy processing facilities. Additionally, the anti-corrosive property of the surface coating was tested on carbon steel against chlorine ions, a common corrosive agent found in the food industry. Accelerated corrosion and long-term chemical exposure studies were conducted to measure the coating stability against the harsh corrosive agents.Publication Adsorption column studies to predict the flow of nutrients through heterogenous porous media under equilibrium and isothermal conditions(2012-09) Pandey, Vijai BBecause of the endangerment of life of the human beings due to the environmental pollution, a serious study of the pollution of the environment is most vital. Because of increasing surface water pollution there is great hazard of ground water pollution. About half the United States of America derives drinking water from aquifers and much of the projected demand is expected to be met from subsurface sources. Therefore, a study was needed to determine the process of ground water contamination due to nutrients, especially Nitrogen, its degree and Length and Time of Travel and factors inhibiting its flow through soil. The present study was undertaken at the 'Pine Crest Duck Farm' at Sterling, Massachusetts, where the nature of the soil was Gravely Sandy Loam and Three unlined (from the side and bottom) waste stabilization ponds existed and there was a great danger of ground water contamination due to Nitrogen in the vicinity of ponds and further. In the field, observation wells were installed along the redial line and bi-monthly samples of water were taken to monitor the levels of B.O.D., Ammonium, Nitrate and Nitrite Nitrogen. Since the Adsorption of the Nitrogen by the soil is great inhibitor in the movement of the Nitrogen through soil profiles, this study was undertaken to study the adsorptive capacity of the soil in 'Bench Tests' and to test the applicability and validity of various adsorption isotherms of nitrogen in the soil; to develop a dimensional model or prediction equation for the nitrogen in the soil under natural flow conditions by studying the effects of varying concentration and flow rates on the adsorptive capacity of the soil, based on the principles of similitude; to correlate adsorption values in bench and column tests; and to determine the length and time of travel of nitrogen through soil. The soil from the Farm was obtained from a depth of six feet with enough care so that original structure was maintained. Adsorptive capacity of the soil was determined through series of 'Bench Tests' and 'Soil Adsorption Columns' in the laboratory under temperature controlled chambers. From the Bench Tests Adsorption values of the soil at various concentrations of Ammonium, Nitrate and Nitrite Nitrogen were determined and validity and applicability of Adsorption isotherms were confirmed. To study the Adsorption Process under natural flow conditions 'Soil Adsorption Column Tests' were done by using never done before Dimensional Model Analysis of Factors affecting Adsorption and getting dimensionless numbers and further obtaining 'Break Through Curves' at different Concentration and flow rates and Adsorption Values were obtained for Ammonium Nitrogen and Nitrite Nitrogen. Finally, Component and Prediction Equations were obtained for Ammonium Nitrogen and Nitrate Nitrogen. By knowing the Adsorption Values of the soil Length and Time of Travel of Ammonium and Nitrate Nitrogen through soil was calculated at various Concentration Levels. A mathematical Prediction Equation was also obtained between Bench and Column Tests and Length of Time of Travel, t predict the adsorption values under natural flow conditions by just performing less time consuming Bench Tests. It was also found that under eqUilibrium Bench Test conditions and natural flow conditions, adsorption of Ammonium, Nitrate and Nitrite Nitrogen increased with increasing solution concentration and adsorption of Ammonium Nitrogen was considerably higher than Nitrate and Nitrite Nitrogen. It was further found that for solution concentrations of 20, 40, 60, 80 and 100 mgll Ammonium Nitrogen and nitrate nitrogen will travel one foot distance in 183 and 115 days; 168 and 111 days; 148 and 98 days; 145 and 81 days; 130 and 98 days; and 127 and 97 days respectively. It was determined that at the present time contamination of shallow water wells does not pose Nitrogen contamination problem and installation of these wells beyond 300 feet radial distance from the waste stabilization ponds was safe.Publication Lactic Acid Bacteria Mediated Phenolic Bioactive Modulation From Fruit Systems For Health Benefits(2013-02) Ankolekar, ChandrakantChronic oxidation linked diseases are on a rise and are one of the leading causes of death globally. Epidemiological evidence increasingly points towards consumption of fruits and vegetables as a preventive way to manage early stages of chronic oxidation linked diseases. Oxidation linked diseases are caused by excessive reactive oxygen species (ROS) generated by a disruption in cellular antioxidant homeostasis due to an overload of calories combined with stress, no excerise and a diet low in antioxidants. Phenolic compounds can not only act as antioxidants but also stimulate the activities of antioxidants enzyme through protective pathways which can help modulate cellular protection. The aim of this dissertation was to use probiotic fermentation to enhance the phenolic and antioxidant compounds in fruit systems which can form the basis of functional food design. The potential of these food systems for disease prevention was investigated in eukaryotic systems through understanding the role of critical metabolic pathways involed in prevention of oxidation linked chronic diseases. Based on structure-function rationale, antioxidant, anti-hyperglycemia and anti-hypertensive potential of phenolic compounds in tea and the effect of extraction time and different degrees of fermentation were investigated in in vitro models. Results indicated that the most fermented teas and a longer extraction time had the highest potential. Further these extracts also had higher H. pylori inhibition potential. Probiotic fermentation of fruit juices with L. helveticus was used to mobilize phenolics and improve biological functionality by maintaining a consistent phytochemical profile. Results indicated that total phenolic and antioxidant potential decreased with feremnetation. However α-glucosidase inhibitory activity and H. pylori inhibitory potential increased with fermentation. Investigation into the mechanism of H. pylori inhibition with fermented cherry extracts revealed inhibition of proline dehydrogenase as the likely mode of action. The potential of fermented apple extracts was further investigated as a phytochemical elicitor in eliciting phenolic and antioxidant response in germinating fava bean. The results indicated a stimulation of phenolic and antioxidant response likely through the stimulation of carbon flux through glycolytic pathways. In yeast, fermented apple extracts accelerated cell death in the presence of peroxide stress in pretreatment model whereas it provided protection against oxidative stress and prevented cell death in concurrent model. Chitosan oligosachharide treatment was investigated as a potential replacement of cancer causing diphenylamine treatment for scald reduction in Cortland apples. Although the treatment did not have any effect on scald reduction, it provides better protection in storage by stimulating phenolic and antioxidant response which related to better health relevant functionality.Publication Strategies to Improve the Performance of Antioxidants in Oil-in-Water Emulsions(2012-09) Panya, AtikornDue to the limited number of approved antioxidants for food applications, several alternative strategies to improve antioxidant performance have been developed by focusing on synergistic antioxidant interactions. Susceptibility to lipid oxidation in food systems is the result of the summation of antioxidative and prooxidative mechanisms. Understanding the sometimes paradoxical behavior of antioxidants and prooxidants is a vital key to design synergistic antioxidant systems suitable for particular foods. This research focused on 3 main strategies to improve the performance of antioxidant activity in oil-in-water emulsions. The first part of this research has been focused on inhibition of lipid oxidation by a combination of the modification of liposomal surfaces by chitosan-coating techniques along with addition of rosmarinic acid esters of varying polarity. Repelling metal ions away from the interface of positively charged liposomes can inhibit lipid oxidation (induced by Fe2+), and also reduce antioxidant loss by Fe3+ reduction. As a result, lipid oxidation can be inhibited synergistically because of a reduction in the prooxidant activity of iron. Second, understanding non-linear antioxidant behavior (the cut-off effect) of antioxidant esters in oil-in-water (O/W) emulsions was also studied to determine how the distributions and locations of antioxidants impacted their antioxidant activity. Antioxidant activity of rosmarinic acid was improved by esterification with alkyl chain lengths between 4 to 12 carbons due to increased ability to partitioning at the interface in oil-in-water emulsions. Surfactant micelles which could increase or decreased the concentration of the antioxidants at the emulsion droplet interface altered antioxidant activity. In the last part of this research, rosmarinic acid and its esters were found to be an excellent tool for studying how antioxidant location could impact its ability to interact with Œ±-tocopherol in O/W emulsions. Synergistic, additive, and antagonistic effects were observed in the combinations between the rosmarinate esters with Œ±-tocopherol. Increases in alkyl chain lengths of rosmarinic acid have influenced both the partitioning of the rosmarinate esters as well as their ability to they interact with Œ±-tocopherol at the interface of oil-in-water emulsions. Fluorescence quenching and EPR studies showed that water soluble rosmarinic acid (R0) exhibited more interactions with √°-tocopherol than any of the esters (R4-R20). Synergistic antioxidant interactions between rosmarinic acid and Œ±-tocopherol could not be explained by electron transfer mechanisms, but formation of caffeic acid from rosmarinic acid. Due to the thermodynamic infeasibility and the fact that increases in Œ±-tocopherol degradation rates, Œ±-tocopherol could not be regenerated efficiently by rosmarinic acid. This formation of caffeic acid was proposed to be responsible of the synergistic activity of R0 and Œ±-tocopherol since the formation of an additional antioxidant could further increase the oxidative stability of the emulsion.Publication Fabrication, Characterization and Utilization of Filled Hydrogel Particles as Food Grade Delivery Systems(2012-09) Matalanis, Alison M.Filled hydrogel particles consisting of emulsified oil droplets encapsulated within a hydrogel matrix were fabricated based on the phase separation of proteins and polysaccharides through aggregative and segregative mechanisms. A 3% (wt/wt) pectin and 3% (wt/wt) caseinate mixture at pH 7 separated into an upper pectin-rich phase and a lower casein-rich phase. Casein-coated lipid droplets added to this mixture partitioned into the lower casein-rich phase. When shear was applied, an oil-in-water-in-water (O/W1/W2) emulsion consisting of oil droplets (O) contained within a casein-rich dispersed phase (W1) suspended in a pectin-rich continuous phase (W2) was formed. Acidification from pH 7 to 5 promoted adsorption of pectin onto casein-rich W1 droplets, forming filled hydrogel particles. Particles were then cross-linked using transglutaminase. Particles were assessed for stability to changes in pH, increasing levels of salts (sodium chloride and calcium chloride), and susceptibility to lipid oxidation. Both cross-linked and not cross-linked particles were stable at low pH (pH 2-5). At high pH, cross-linked particles maintained their integrity while not cross-linked particles disintegrated. Particles were stable to sodium chloride (0-500 mM). Calcium chloride levels above 4 mM resulted in system gelation. The rate of lipid oxidation for 1% (vol/vol) fish oil encapsulated within filled hydrogel particles was compared to that of oil-in-water emulsions stabilized by either Tween 20 or casein. Emulsions stabilized by Tween 20 oxidized faster than either filled hydrogel particles or casein stabilized emulsions, while filled hydrogel particles and casein stabilized emulsions showed similar oxidation rates. Using an in-vitro digestion model, the digestion of lipid encapsulated within filled hydrogel particles was compared to that of a casein stabilized oil-in-water emulsion. Results showed similar rates of digestion for both hydrogel and emulsion samples. Attempts to fabricate particles using free oil (rather than emulsified oil) were unsuccessful and resulted in the formation of large non-encapsulated oil droplets (d ~10 μm). By controlling particle concentrations of biopolymer, water, and oil, it was possible to fabricate particles that were highly resistant to gravitational separation which was attributed to the equivalent density of the continuous and particle phases. Results highlight the potential applications and versatility of this delivery system.Publication Minor Components and Their Roles on Lipid Oxidation in Bulk Oil That Contains Association Colloids(2012-05) Chen, BingcanThe combination of water and surface active compounds found naturally in commercially refined vegetable oils have been postulated to form physical structures known as association colloids. This research studied the ability of 1,2-dioleoyl-sn-glycerol-3-phosphocholine (DOPC) and water to form physical structures in stripped soybean oil. Interfacial tension and fluorescence spectrometry results showed the critical micelle concentration (CMC) of DOPC in stripped soybean oil was 650 and 950 microM, respectively. Light scattering attenuation results indicated that the structure formed by DOPC was reverse micelles. The physical properties of DOPC reverse micelles were determined using small-angle X-ray scattering (SAXS) and fluorescence probes. These studies showed that increasing the water concentration altered the size and shape of the reverse micelles formed by DOPC. The impact of DOPC reverse micelles on the lipid oxidation of stripped soybean oil was investigated by following the formation of primary and secondary lipid oxidation products. DOPC reverse micelles had a prooxidant effect, shortening the oxidation lag phase of SSO at 55 °C. It also was not able to change the lipid oxidation of stripped soybean oil compared with DOPC reverse micelles at same concemtration ( i.e., 950 microM). 1,2-dibutyl-sn-glycerol-3-phosphocholine (DC4PC) which has the shorter fatty acid than DOPC was not able to form association colloids and did not impact lipid oxidation rates. This indicated that the choline group of the phospholipid was not responsible for the increased oxidation rates and suggested that the physical structure formed by DOPC was responsible for the prooxidant effect. The impact of the DOPC reverse micelles on the effectiveness and physical location of the antioxidants, alpha-tocopherol and Trolox was also studied. Both non-polar (alpha-tocopherol) and polar (Trolox) were able to inhibit lipid oxidation in stripped soybean oil in the presence of DOPC reverse micelles. Trolox was a more effective antioxidant than alpha-tocopherol. Fluorescence steady state and lifetime decay studies suggested that both alpha-tocopherol and Trolox were associated with DOPC reverse micelle in bulk oil. Trolox primarily concentrated in the water pool of reverse micelle since it quenched NBD-PE fluorescence intensity with increasing concentrations. A portion of alpha-tocopherol was also associated with the aqueous phase of the DOPC reverse micelles but this was likely at the oil-water interface since alpha-tocopherol is not water soluble. The addition of ferric chelator, deferoxamine (DFO) to stripped soybean oil significantly prevented the lipid oxidation caused by DOPC reverse micelles as the lag phase was extended from 2 to 7 days. DFO was also found to increase the antioxidant activity of both Trolox and alpha-tocopherol. Trolox and alpha-tocopherol were found to be rapidly decomposed by high-valence Fe(III) while low-valence-state (Fe (II) was much less reactive. Fe(III) was also consumed by both hydrophilic Trolox and lipophilic alpha-tocopherol presumably though reduction to Fe (II). DOPC reverse micelles were able to decrease antioxidants-iron interactions as evidence by a decrease in antioxidant depletion by iron and a decrease in iron reduction by the antioxidants. These results suggested that the ability of DFO to increase the antioxidant activity of alpha-tocopherol and Trolox was due to its ability to decrease free radical production and not its ability to decrease direct iron-antioxidant interactions. Overall, the results presented in this dissertation show phospholipids and water can form reverse micelles in edible oils. These reverse micelles increase lipid oxidation rates by increasing the prooxidant activity of iron. Free radical scavenging antioxidants can inhibit oxidation promoted by the reverse micelles with polar Trolox being more effective than non-polar alpha-tocopherol presumably because Trolox is more highly associated with the reverse micelle. The reverse micelles produced by DOPC protected alpha-tocopherol and Trolox from direct degradation by iron. The knowledge gained from this study will improve our understanding of the mechanism of lipid oxidation in bulk oils which will hopefully provide new technologies to improve the oxidation stability of edible oils. For example, it may be able to use oil refining technologies to remove prooxidative minor components that for physical structure in bulk oils.Publication Effects of Free Fatty Acids, Mono- and Diacylglycerols on Oxidative Stability of Soybean Oil-In-Water Emulsions(2011-05) Waraho, ThaddaoEven though edible oils undergo refining processes to remove undesirable components, commercial oils still contain small amounts of minor components that can contribute to either prooxidant and antioxidant pathways which ultimately affect the quality of the oils. The objective of this research was to determine the role of free fatty acids and mono- and diacylglycerols on the oxidative stability of oil-in-water emulsions. Free fatty acids acted as a strong prooxidants in stripped soybean oil-in-water emulsions. Concentrations as low as 0.1% of the lipid accelerated lipid oxidation rate by both shortening the lag phase of lipid hydroperoxide and hexanal formation. The results showed that the most likely mechanisms for the prooxidant activity of free fatty acids is through their ability to increase the negatively charge on emulsion droplets that in turn could attract the cationic transition metals to the emulsion droplet surface where they can interact with lipid and thus promote oxidation. The prooxidant activity of free fatty acids was dependent on fatty acid type with lipid oxidation rates being in the order of linolenic < linoleic < oleic. Surprisingly, an increase in the degree of unsaturation of the free fatty viii acids lowered the ability of the free fatty acids to promote oxidation which may be due to their differences in geometric shape thus influencing their ability to access the emulsion droplet interface and increase the negative charge. Overall, free fatty acids are strong prooxidants in oil-in-water emulsions. This prooxidant activity is dependent not only on their concentration but also on the molecular structure of the fatty acid. Addition of mono- and diacylglycerols in oil-in-water emulsions showed an antioxidative effect in both non-stripped and stripped soybean oil. Addition of 1-monooleoylglycerol only had a small impact on the oxidative stability of non-stripped soybean oil-in-water emulsions but did inhibit lipid oxidation in emulsions prepared with stripped soybean. Much stronger antioxidant activity was observed upon the addition of 1,2-dioleoyl-sn-glycerol to both non-stripped and stripped soybean oil-in-water emulsions. Both lipid hydroperoxide and hexanal formation decreased with increasing 1,2-dioleoyl-sn-glycerol concentrations with 2.5% 1,2-dioleoyl-sn-glycerol almost completely preventing hydroperoxide and hexanal production over the course of the study. Overall, these results suggest that diacylglycerols could be an effective antioxidant in oil-in-water emulsions which possibility due to their ability to form a liquid crystal phase which could form a physical barrier that decreases interactions between unsaturated fatty acids in the emulsion droplet core and prooxidants or oxygen in the aqueous phase of the emulsion. However, the antioxidant mechanism of diacylglycerols is not currently understood and needs further investigation.Publication Fabrication of Protein-Polysaccharide Particulates through Thermal Treatment of Associative Complexes(2009-09) Jones, Owen GriffithMixed solutions of β-lactoglobulin and anionic polysaccharides, specifically pectin, were formed into associative complexes through pH reduction from neutral conditions. Thermal treatment of these associative complexes was investigated as a function of biopolymer composition, heating conditions, pH, and ionic strength. Thermal treatment of β-lactoglobulin-pectin complexes at pH 4.5 – 5.0 was found to create protein-based particulates of consistent and narrow size distribution (diameter ~ 150 – 400 nm). These particulates were relatively stable to further pH adjustment and to high levels of salt (200 NaCl). Particle characteristics were maintained after re-suspending them in aqueous solutions after they have been either frozen or lyophilized. Thermal analysis of β- lactoglobulin-pectin complexes using calorimetry (DSC) and turbidity-temperature scanning indicated that the denaturation of β-lactoglobulin was unaffected by pectin, but protein aggregation was limited by the presence of pectin. Biopolymer particles formed using two different methods were compared: Type 1 – forming β-lactoglobulin nanoparticles by heating, then coating them with pectin; Type 2 – forming particles by heating β-lactoglobulin and pectin together. Type 2 particles had smaller diameters and had better pH and salt stability than Type 1 particles. It was proposed that Type 2 particles had a pectin-saturated surface that limited their aggregation, whereas Type 1 particles had “gaps” in the pectin surface coverage that led to greater aggregation. Finally, the possibility of controlling the size and concentration of biopolymer particles formed by heating β-lactoglobulin-pectin complexes by controlling preparation conditions was studied. Biopolymer particle size and concentration increased with increasing holding time (0 to 30 minutes), decreasing holding temperature (90 to 70 ºC), increasing protein concentration (0 to 2 wt%), increasing pH (4.5 to 5.0), and increasing salt concentration (0 to 50 mol/kg). The influence of these factors on biopolymer particle size was attributed to their impact on protein-polysaccharide interactions, protein denaturation, and protein aggregation kinetics. The knowledge gained from this study will facilitate the rational design of biopolymer particles with specific physicochemical and functional attributes that can be used in the food and other industries, e.g., for encapsulation, texture modification, optical properties modification.