Life Sciences Commons^™

Analysis Of Micro(Nano)Plastics In Food Using Raman Microscopy, Xin Guo

Doctoral Dissertations

Microplastic pollution has emerged as a global concern in both aquatic and terrestrial environments. The presence of microplastics in the food chain poses a potential threat to human health. To accurately assess the risks associated with microplastics, it is crucial to have a reliable analytical technique capable of detecting, quantifying, and identifying microplastics of varying materials, sizes, and shapes in environmental, agricultural, and food samples. Spectroscopic techniques, specifically vibrational spectroscopy (Raman and Infrared), are extensively utilized in microplastic analysis. These techniques enable rapid and high-throughput identification, while also providing size and shape information. However, there are certain gaps in the …

Detection And Control Of Environmentally Transmissible Viruses, Anand R. Soorneedi

Doctoral Dissertations

Viruses, owing to their ubiquitous nature and ability to infect almost every other species, have long been a subject of interest for scientists. Some of the virus species can be very deadly to humans and animals alike and can impose a huge economic and health burden across the world. The recent CoVID-19 pandemic underscores the importance of timely detection for developing effective intervention strategies. Unfortunately, some of the virus species that cause significant health and economic impacts do not have robust and reliable detection methods due to several reasons. In some cases, despite having gold standard methods for detection of …

Understanding And Developing Safer Sanitation Agents And Strategies In Food Production Environments, Pragathi Kamarasu

Doctoral Dissertations

Food is a primary resource for survival of human beings, and it is also one of the primary resources for spread of infectious diseases. When both these factors come together it does not only cause ill effects on our health but also causes a burden on the food and agricultural industry. Through the help of science, us researchers and scientists have always tried to reduce this burden. And I hope like a drop of water in the ocean in some way my research contributes towards this. According to WHO currently in 2023 there are about 1 in 10 people falling …

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 …

Bifidobacterial Metabolism Of Fucosylated Human Milk Oligosaccharides Influences Structure And Function Of The Infant Gut Microbiome, Liv R. Dedon

Doctoral Dissertations

Human milk contains human milk oligosaccharides (HMOs) that are indigestible and pass intact through the infant gastrointestinal tract where they are available for microbial metabolism. HMOs incorporate the same monosaccharide building blocks but vary structurally in primary sequence of monomeric components. Primary sequences are further diversified by degree of polymerization, branching, and secondary modifications such as fucosylation. Fucosylated HMOs (fHMOs) are highly abundant and can account for over 30% of total HMOs. Infant-colonizing Bifidobacterium longum subsp. infantis (B. infantis) possesses a specialized gene cluster conveying the ability to metabolize fHMOs. This study presents an in-depth analysis of B. …

The Genomic Dynamics Of Fermented Food Microbes, Katherine Chacón-Vargas

Doctoral Dissertations

Along with the agriculture and domestication revolution, humans have utilized bacteria, yeasts, and molds for millennia in the production of traditionally fermented foods and beverages. Fermentation is a very ancient practice of high relevance nowadays since it contributes with a great variety of foods worldwide. Microbial fermentation allows metabolic transformation of the raw food materials leading to biochemical changes that played a key role in food preservation, health benefits, nutrition, flavors, and texture, among others. Food fermentation practices could diverge from traditional artisanal spontaneous fermentation to industrialize methods with specialized microbial starters and although fermented environments tend to be very …

Microwave Frequency Control Algorithms For Use In A Solid-State System To Achieve Improved Heating Performance, Ran Yang

Doctoral Dissertations

Microwave is a popular food heating technique. Its unique volumetric heating principle enables fast heating while also leads to nonuniform heat distribution, where the standing wave patterns caused by the magnetron as microwave source is the main reason for the poor uniformity. Solid-state microwave generator is a promising solution to address the nonuniform heating, as it allows flexible microwaves, with frequencies in a range rather than fixed, and thereby, the varied thermal patterns by different frequencies could overcome the standing wave pattern issue. Previous studies on the frequency control strategy mainly focused on orderly shifting frequencies in range, while not …

Analysis Of Food Colorants Using Raman Spectroscopy, Haochen Dai

Doctoral Dissertations

Color is one of the most important quality attributes that affect consumers' selection of food. The increasing demand of consumers for natural colorants over artificial ones has placed challenges in both product development and regulatory practices. However, current analytical solutions for food colorants are mostly limited to a sophisticated laboratory setting with tedious sample preparation procedures. Herein, this research focuses on the analytical developments toward cost-effective determination of colorant adulteration and stability analysis. The main technique explored is Raman spectroscopy, which measures the inelastic light scattering and allows one to obtain unique molecular fingerprints for specific molecules. Compared with chromatographic …

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 …

Enhancement In Photoinactivation Of Food-Borne Pathogenic Bacteria With The Use Of Curcumin And Surfactants, Victor Ryu

Doctoral Dissertations

Photosensitizers and UV or visible light could photoinactivate bacteria. Curcumin was utilized as a food-grade photosensitizer, and an enhancement of its water-dispersibility, chemical stability, and antimicrobial activity when introduced into surfactant solutions was observed. Stock curcumin-surfactant solutions were prepared by titrating curcumin dissolved in ethanol into either Surfynol 465 or Tween 80 solutions (5 mM sodium citrate buffer). Stock curcumin surfactant solutions with different surfactant concentrations were diluted to 1 µM prior to irradiation. The resulting solutions also had surfactant concentrations below, near, and above their critical micelle concentrations (CMCs) of the respective surfactants. The antimicrobial activity of the curcumin-loaded …

Chemistry And Functionality Of Plant Waxes: Applications Toward Postharvest Coatings, Francisco Miguel Angel Leyva Gutierrez

Doctoral Dissertations

The cuticle of all higher-plants is covered in lipidic layers of amorphous and crystalline waxes. The chemical composition and structure of cuticular waxes impart numerous functional properties to the surfaces of plants. Moreover, plant waxes are valuable industrial products with myriad applications; the postharvest coating of agricultural commodities for preservation serves as a salient example. There is an unfulfilled need in the agricultural sector for alternative wax materials to reduce reliance on imported waxes of botanical origin. Plant waxes are inherently complex mixtures composed of n-alkanes, as well as aliphatic alcohols, aldehydes, fatty acids, ketones, esters, and derivatives thereof. …

Double Emulsions Relevant To Food Systems: Fabrication, Characterization, And Applications, Jinning Liu

Doctoral Dissertations

Systems of the W/O/W type continue to be of growing interest to food scientists and technologists for two main reasons. First, there is the possibility of preparing a reduced-fat emulsion product by the replacement of a conventional oil-in-water emulsion by the equivalent W/O/W emulsion having a lower actual oil content but a similar in-mouth perceived texture. Second, there is the capability to encapsulate and protect a sensitive hydrophilic bioactive compound. However, it is always a bottleneck to obtain robust formulations using economically viable ingredients and processing operations. To improve its performance for practical applications in food production, efforts have been …

Detection Of Mycotoxins Using Surface-Enhanced Raman Spectroscopy, Lourdes B. Martinez Rojas

Doctoral Dissertations

Mycotoxins are toxic metabolites produced by fungus that can be parasites or saprophytes of crops or livestock forage. Consumer demand for plant-based foods and interest in animal-based foods originating from animals fed plant-based feed has been on the rise. Therefore, monitoring mycotoxins occurring in the food supply is more critical than ever. The goal of this project is to improve surface-enhanced Raman spectroscopy’s (SERS) ability to identify and detect mycotoxins using label-free SERS substrates. Two simple approaches were designed to enhance the detection of mycotoxins produced by the Aspergillus and Penicillium genera, ochratoxin A and aflatoxin B1. Ochratoxin A was …

Fate And Effect Of Food-Grade Titanium Dioxide Particles/Polystyrene Nanoplastics On Nutrients Bioaccessibility Of Food In The Simulated Human Gastrointestinal Tract, Chunyang Li

Doctoral Dissertations

Food grade titanium dioxide particles (E171), as whitening agent, are commonly used in chewing gums, candies, sauces, salad dressings, and powdered milk. Recently, nanoplastics (NPs) (defined as < 1 µm), which are degraded from plastic debris undergoing environmental process, have received global attention. Because nanoplastics are ubiquitous in aquatic and terrestrial systems, and have been detected in marine animals, table salts, drinking water, and air. Thus, the presence of E171 as additives in the food, and the nanoplastics in food chains, both pose potential risks to human health through retarded processes in the gastrointestinal tract (GIT). However, the knowledge about the fate of E171 or nanoplastics and their impact on digestive enzymes activity or nutrient bioaccessiblity are currently limited. Therefore, it is necessary to investigate potential impacts of E171 or nanoplastics on digestion processes and nutrient bioaccessibility in the simulated human gastrointestinal tract, which includes mouth, stomach and intestinal phases, to mimic the digestion processes of food incubating with E171 or polystyrene (PS) nanoplastics. The objectives of my dissertation and major findings are presented below: 1) The impacts of E171 on lipid digestion and vitamin D₃ (VD₃) bioaccessibility encapsulated within oil-in-water emulsions in a simulated human gastrointestinal tract model were explored; 2) The impacts of E171 on the bioaccessibility of minerals (Ca, K, Mg, Fe, Mn, Zn, P and S) released from spinach leaves using a simulated human digestion tract were investigated; 3) The impacts of various concentrations or different functional group (-COOH, -NH₂) of PS NPs on the starch hydrolysis in the simulated …

Mapping Selected Polyphenols Metabolism By Gut Bacteria And Their Genes, Ermin Zhao

Doctoral Dissertations

The human gut microbiome is a huge enzyme repository for dietary polyphenols metabolism, especially considering most of the polyphenols cannot be digested in the host and their biological functions are limited. Poor bioaccessibility based on traditional pharmaceutical ADME (absorption, distribution, metabolism, and excretion) assessment is the main problem facing the widely medical application of most polyphenols. Gut bacteria have the potential to mediate a wide range of biotransformation reactions of polyphenols, which leads to the production of many bioactive metabolites. In the past decades, mounting evidence in traditional ADME study have demonstrated gut bacteria play an irreplaceable role in dietary …

Porous Food Microparticles As Carriers Of Lipophilic Bioactive Compounds To Improve Functionalities, Inseob Choi

Doctoral Dissertations

Lipophilic bioactive compounds (LBCs) have been gaining attention due to their antioxidation and health-promotion properties. Although many delivery systems have been studied to encapsulate LBCs to increase stability and bioaccessibility of the LBCs, most of delivery systems lack of practicality for application in the food industry due to energy-extensive encapsulation processes and high-cost carrier materials used. Additionally, while a variety of encapsulating systems exist in nanoscale to achieve efficient encapsulation of LBCs, nanoscale systems with encapsulated LBCs may be subjected to reassessment of toxicity. In this dissertation, freeze-dried potato microparticles (FDPMs) and freeze-dried mushroom microparticles (FDMMs) were studied as carrier …

Antibiotic Sensitivity Testing Of Foodborne Bacteria Using Surface-Enhanced Raman Spectroscopy, Joshua Gukowsky

Doctoral Dissertations

The spread of antibiotic resistant bacteria around the world has become a major public health issue, and it is essential that effective detection methods exist for identifying these organisms and preventing them from spreading throughout our food systems and into the environment. The goal of this research is to develop a novel analytical procedure that is capable of easily identifying antibiotic resistance in bacterial samples, and also provides more information about the biochemical characteristics of the bacteria and their responses to antibiotic exposure. Surface-enhanced Raman Spectroscopy (SERS), an analytical technique that uses light scattering to produce a spectrum based on …

Anti-Inflammatory And Chemopreventive Activity Of Lunasin From Tofu Whey For The Management Of Gastrointestinal Diseases, Cindy Andrea Nieto Veloza

Doctoral Dissertations

Gastrointestinal diseases such as inflammatory bowel diseases (IBD) and colorectal cancer (CRC) are pathological conditions associated with chronic inflammation, characterized by intestinal damage, debilitating symptoms, and detrimental health consequences. The increased risk of CRC in IBD patients, and the adverse effects associated with current therapeutic strategies, point out the need for safer alternatives to reduce chronic inflammation in the bowel. Lunasin is a bioactive peptide naturally occurring in soybeans, with chemopreventive and anti-inflammatory properties demonstrated in several extra-intestinal diseases. However, to date, there is no evidence of the biological activity of lunasin on the gastrointestinal tract as a target site. …

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, …

Investigation On The Factors Impacting The Bioaccessibility Of Oil-Soluble Vitamins: Food Matrix Effects, Yunbing Tan

Doctoral Dissertations

Food, nutrition, and pharmaceutical scientists are trying to elucidate the major factors impacting the bioavailability of macronutrients (e.g., lipids), micronutrients (e.g., vitamins), and nutraceuticals (e.g., carotenoids) so as to improve their efficacy. Currently, however, there is a limited understanding of how food matrix effects impact nutrient digestion and bioavailability. In this thesis, the impact of food matrix effects was elucidated by systematically examining the influence of several important factors (including oil type, oil concentration, droplet size, emulsifier type, and nutrient type) on lipid digestion and the bioaccessibility of hydrophobic bioactive agents. Oil-in-water emulsions were used as model …

Formation, Characterization, And Utilization Of Multilayer Nanoemulsions In Foods, Jorge L. Muriel Mundo

Doctoral Dissertations

Multilayer coatings have been proposed as a promising nanotechnology for improving the performance of emulsion-based products in numerous research fields. In foods, these multilayer coatings can be used to improve the encapsulation and protection of bioactive ingredients in delivery systems during storage and passage through the gastrointestinal tract (1, 2). Therefore, there is strong interest in understanding the formation, properties, and performance of these novel coatings. Multilayer coatings are formed by layer-by-layer electrostatic deposition of oppositely charged biopolymers, such as proteins and polysaccharides. A better understanding of the formation and properties of biopolymer multilayer coatings could lead to …

Interactions Between Titanium Dioxide Nanoparticles (Nps) And Mucin, . Boimin

Doctoral Dissertations

Titanium dioxide nanoparticles (TiO₂ NPs) are widely used in many food, consumer, and industrial products. However, little is known about the overall effects of TiO₂ NPs on the environment or human health. In order to elucidate the fate, transformation, transport, and toxicological impact of TiO₂ NPs, a better understanding is needed of how the physicochemical properties of TiO₂ NPs (e.g. size, charge, curvature, hydrophobicity, and surface functionality) interact with their microenvironments (e.g. pH, temperature, bile acids, microbiome, enzymes, surface-active components, and biopolymers). Living organisms including humans have a natural mechanism to protect themselves from physical, biological, …

Coffee Bioactives Regulate Lipid Metabolism In Caenorhabditis Elegans, Renalison Farias Pereira

Doctoral Dissertations

Coffee consumption is associated with reduced risk of metabolic syndrome, obesity and diabetes. Although the mechanisms of action are not yet elucidated, the effects of coffee and its bioactive components on lipid metabolism may account for the overall coffee effects on human health. Therefore, this study investigated the molecular mechanisms of coffee and its bioactive components on lipid metabolism using Caenorhabditis elegans as a model system. Green coffee bean extract (GCBE), the chlorogenic acid 5-O-caffeyolquinic acid (5-CQA), and the coffee diterpenes cafestol and kahweol reduced fat accumulation via distinct lipid metabolism pathways and/or behavior changes in C. elegans …

Effects Of Tempeh Fermentation On Soy Free And Bound Phenolics: Release, Transformation, And Stimulated Production, Amadeus Driando Ahnan

Doctoral Dissertations

The fermentation of tempeh, a traditional source of protein originated in Indonesia, has been reported to enhance the health-promoting potentials of various grains, legumes, and beans. Tempeh fermentation on soybeans can modulate the bioavailability of phenolic compounds, particularly isoflavones, bioactive compounds that have been found to be protective against lung, prostrate, and colon cancers. However, the mechanism of the protective benefits was unknown. Using whole-food and in vitro models, this study addressed this research gap by investigating the effects of tempeh fermentation using various cultures on the compositions of soy free, bound, and minor phenolics, as well as their antioxidative, …

Analysis Of Titanium Dioxide Nanoparticles In Foods Using Raman Spectroscopic Techniques, Janamkumar Pandya

Doctoral Dissertations

Titanium dioxide (TiO2) and its nanoparticles (NPs) are widely used in various applications. Recently, the presence of TiO2 NPs in food and consumer products raised safety concerns to human health and the environment. The goal of this project is to explore the capability of Raman Spectroscopy in the analysis of TiO2-NPs and apply this technique for the analysis of TiO2-NPs in food and environmental samples. Two approaches, i.e. the ligand-based and the mapping-based, were evaluated. The ligand-based approach utilized the surface enhanced Raman scattering (SERS) property of the TiO2 NPs as a substrate to enhance the signal of a surface …

Micro-Physiological Models To Mimic Mucosal Barrier Complexity Of The Human Intestine In Vitro, Abhinav Sharma

Doctoral Dissertations

The mucosal barrier in the intestine is vital to maintain selective absorption of nutrients while protecting internal tissues and maintaining symbiotic relationship with luminal microbiota. This bio-barrier consists of a cellular epithelial barrier and an acellular mucus barrier. Secreted mucus regulates barrier function via in situ biochemical and biophysical interaction with luminal content that continually evolves during digestion and absorption. Increasing evidence suggests that a mucus barrier is indispensable to maintain homeostasis in the gastrointestinal tract. However, the importance of mucus barrier is largely underrated for in vitro mucosal tissue modeling. The major gap is the lack of experimental material …

Enteric Biopolymer Composite Coatings To Enhance The Viability Of Powdered Probiotics During Preparation, Storage, And Simulated Digestions, Anyi Wang

Doctoral Dissertations

Due to suppressed metabolisms, powdered probiotics are generally more stable and more convenient for applications than the liquid form, but much work is needed to improve viability of powdered probiotics during processing, storage, and digestions. The goal of this dissertation was to fabricate delivery systems with an enteric biopolymer coating and a core of powdered probiotic ingredients. The principle of preparing powdered probiotics was to directly mix a concentrated cell suspension with hygroscopic food ingredient powders. Amorphous spray-dried lactose (SDL) was first studied to prepared powdered Lactobacillus salivarius NRRL B-30514 in chapter 2. A smaller amount of cell suspension resulted …

Microemulsions Of Cinnamon And Orange Oils As An Antimicrobial Delivery System For Salmonella Biofilms On Stainless Steel, Jennifer Vuia-Riser

Doctoral Dissertations

Essential oils (EOs) are natural antimicrobials that can be used to develop intervention strategies to inhibit pathogens, but EOs are lipophilic. Colloidal systems, such as microemulsions, are needed for food industry applications. This dissertation focused on the development and characterization of a microemulsion composed of cinnamon oil (CO, Cinnamomum zeylanicum) and orange oil (OO, Citrus sinensis) to be used against Salmonella Enteritidis H4267 biofilms formed on stainless steel disc surfaces.

First, the antimicrobial activity of CO and OO against S. Enteritidis H4267, either used in combination or in a microemulsion system, was determined. CO had a greater antimicrobial …

Design And Fabrication Of Colloidal Delivery Systems To Encapsulate And Protect Curcumin: An Important Hydrophobic Nutraceutical, Mahesh Kharat

Doctoral Dissertations

Curcumin is a polyphenolic compound found in Turmeric (Curcuma longa) rhizome that has excellent biological benefits such as antioxidant, anti-inflammatory, and anti-cancer properties to name a few. However, its incorporation in food and pharmaceuticals is difficult due to low water solubility and chemical instability. This study focuses on developing colloidal delivery systems for efficient encapsulation and increased protection of curcumin for maximizing the proposed health benefits of curcumin. It was found that the physical and chemical stability of pure curcumin is impacted by pH, storage temperature, and molecular environment both in aqueous solutions and in oil-in-water emulsions. Pure …

Promotion Of Colon Health By Strawberry And Cranberry, Yanhui Han

Doctoral Dissertations

Inflammatory bowel disease (IBD) has posed serious threats to the human health, which lead to chronic malabsorption of nutrients, abnormal pain and rectal bleeding. Both genetic predisposition and environmental factors contribute to the onset of IBD. Multiple studies suggested that dysbiosis in colon plays an important role in the development of colitis, and gut microbiota composition are different between patients with IBD and healthy individuals. Intake of whole foods, such as fruits and vegetables, may confer health benefits to the host. The beneficial effects of fruits and vegetables mainly attribute to their richness of polyphenols and microbiota-accessible carbohydrates (MACs). Components …