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Full-Text Articles in Life Sciences

Synthesis Of Some Biobased Surfactants, And Their Functionalities As Emulsifiers And Antimicrobial Agents., Kangzi Ren Jan 2018

Synthesis Of Some Biobased Surfactants, And Their Functionalities As Emulsifiers And Antimicrobial Agents., Kangzi Ren

Graduate Theses and Dissertations

Biobased surfactants, which are biochemicals derived from biological resources via various methods like enzymes and microbial fermentation, can achieve similar application functionality to petroleum-based surfactants. The conventional surfactants could face challenges in terms of limited fossil fuel availability, harsh processing conditions, low biodegradability and high aquatic toxicity. Biobased surfactants, on the other hand, can address some of these challenges; however, they also have their own challenges, for example, lower yield and production rate compared with conventional surfactant production method.

The overall goal of this work was to investigate the synthesis of specific biobased surfactants and evaluate their functionalities for potential ...


Use Of Different Ripening Inhibitors To Enhance Antimicrobial Activity Of Essential Oil Nanoemulsion, Victor Ryu Oct 2017

Use Of Different Ripening Inhibitors To Enhance Antimicrobial Activity Of Essential Oil Nanoemulsion, Victor Ryu

Masters Theses

The objective of this research was to study the impact of ripening inhibitor level and type on the formation, stability, and activity of antimicrobial thyme oil nanoemulsions formed by spontaneous emulsification. Oil-in-water antimicrobial nanoemulsions (10 wt%) were formed by titrating a mixture of essential oil, ripening inhibitor, and surfactant (Tween 80) into 5mM sodium citrate buffer (pH 3.5). Stable nanoemulsions containing small droplets (d < 70 nm) were formed. The antimicrobial activity of the nanoemulsions decreased with increasing ripening inhibitor concentration, which was attributed to a reduction in the amount of hydrophobic antimicrobial constituents transferred to the separated hydrophobic domain, mimicking bacterial cell membranes, by using dialysis and chromatography. The antimicrobial activity of the nanoemulsions also depended on the nature of the ripening inhibitor used: palm ≈ corn > canola > coconut which also depended on their ability to transfer hydrophobic antimicrobial constituents to the separated hydrophobic domain.


Influence Of Biomimetic Chelating Packaging On Natural Antimicrobial Efficacy, Paul Castrale Oct 2017

Influence Of Biomimetic Chelating Packaging On Natural Antimicrobial Efficacy, Paul Castrale

Masters Theses

The iron chelating molecule, ethylenediaminetetraacetic acid (EDTA) is used in food applications for the preservation of oxidation prone ingredients. Research has suggested that EDTA is also capable of enhancing the antimicrobial effectiveness of various compounds including naturally-derived antimicrobials. With consumer demand for cleaner food labels, there remains an opportunity to introduce new chelating technology to replace synthetically-derived EDTA. Through photographting and chemical conversion, hydroxamic acid ligands were covalently bound to polypropylene films resulting in polypropylene-graft-poly(hydroxamic acid) (PP-g-PHA). The resulting films demonstrated an ability to chelate 64 nmol/cm2 from an iron saturated environment or ...


Antimicrobial Inhibitory Activities Of Phenolic Extracts From Four Selected Soybean Hulls In Culture And Chicken Skin Model Systems, And Preliminary Ace-Inhibitory Activity, Rajaa Abdulkair Abutheraa Dec 2016

Antimicrobial Inhibitory Activities Of Phenolic Extracts From Four Selected Soybean Hulls In Culture And Chicken Skin Model Systems, And Preliminary Ace-Inhibitory Activity, Rajaa Abdulkair Abutheraa

Theses and Dissertations

Soybean components provide health benefits to humans. Soybean hulls, a major by-product of the soybean processing industry consist of complex carbohydrates, proteins, lipids and polyphenols such as anthocyanidins, proanthocyanidins and isoflavones. The polyphenolic compounds in the hulls give them various colors such as black, brown, green, yellow or even a mottled appearance. Studies have reported different soybean varieties with varying total phenolic compounds in their seed hulls, which have antioxidant property. Phenolic extracts can be used as substitutes for synthetic antimicrobials and preservatives to assist in preventing the growth of pathogens such as Salmonella Typhimurium, E coli 0157:H7, and ...


Switchgrass Extractives Have Potential As A Value-Added Antimicrobial Against Plant Pathogens And Foodborne Pathogens, Alexander Ian Bruce Dec 2016

Switchgrass Extractives Have Potential As A Value-Added Antimicrobial Against Plant Pathogens And Foodborne Pathogens, Alexander Ian Bruce

Masters Theses

Panicum virgatum (switchgrass), a perennial grass native to North America, is a leading biomass feedstock candidate for the manufacture of cellulosic ethanol. Switchgrass is considered a viable option for biofuel production due to its cheap production cost and ability to grow on marginal land. Biofuel derived from switchgrass has been shown to be very energy efficient, producing 540% more renewable energy versus nonrenewable energy expended. Switchgrass-derived biofuel is also estimated to have greenhouse gas emissions that are 94% lower than emissions from gasoline (Schmer et al 2008). Biofuels are created through biochemical processes that utilize various enzymes and microorganisms for ...


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 ...


Efficacy Of Buffered Propionic Acid Against Salmonella Typhimurium In Ground Pork Stored At 4°C And 10°C And Inhibition Of Listeria Monocytogenes By Buffered Dry Vinegar In Ready-To-Eat Uncured Turkey Stored At 4°C, Mani Kumar Badvela Jan 2016

Efficacy Of Buffered Propionic Acid Against Salmonella Typhimurium In Ground Pork Stored At 4°C And 10°C And Inhibition Of Listeria Monocytogenes By Buffered Dry Vinegar In Ready-To-Eat Uncured Turkey Stored At 4°C, Mani Kumar Badvela

Graduate Theses and Dissertations

The objective of the first study was to evaluate the antimicrobial efficacy of buffered propionic acid-based antimicrobials (BP-6 buffered to pH 6; BP-5 buffered to pH 5) against Salmonella Typhimurium (ST) inoculated by two methods in ground pork (1) Addition of antimicrobial to ground pork followed by inoculation with Salmonella Typhimurium (2) Addition of Salmonella Typhimurium to ground pork followed by addition of antimicrobial. This study was undertaken to check if there would be any difference in the antimicrobial efficacy of buffered propionic acid if added before or after Salmonella addition to ground pork. Ground pork treatments consisted of 0 ...


Physicochemical And Toxicological Assessment Of Antimicrobial Ε-Polylysine-Pectin Complexes, Cynthia L. Lopez Pena Aug 2015

Physicochemical And Toxicological Assessment Of Antimicrobial Ε-Polylysine-Pectin Complexes, Cynthia L. Lopez Pena

Doctoral Dissertations

ε-Polylysine is an appealing FDA-approved, all natural antimicrobial biopolymer effective against a wide range of microorganisms. Its implementation is greatly limited by its strong cationic charge, which has been linked to instability in food systems, perceived astringency and bitterness, and the ability to inhibit lipid digestion. Previous studies have shown that controlled complexation of ε-polylysine with anionic pectin is able to prevent instability and astringency in simplified model food systems, while maintaining the antimicrobial character of polylysine. Isothermal titration calorimetry, micro-electrophoresis, microscopy, and turbidity analyses of the stability of electrostatic pectin-polylysine complexes in the presence of strongly anionic κ-carrageenan, and ...


Biofilm Production By Food-Transmitted Bacteria And Their Control By Selected Nanoparticles, Mariam Al Shamsi May 2015

Biofilm Production By Food-Transmitted Bacteria And Their Control By Selected Nanoparticles, Mariam Al Shamsi

Theses

Biofilm is a population of bacteria attached to any types of surfaces and impeded in a self-produced matrix of extracellular polymeric substances. Biofilm exhibit up to 1000 fold antibiotic increased resistance to a broad range of antimicrobial agents. Several food-transmitted microorganisms are capable of forming biofilms and considered as a major source of contamination, transmission and infection. In the last few decades, nanoparticles has gained a great attention for their potential applications as antimicrobial agents. The aim of this work was to assess the biofilm formation capacity of food-transmitted bacteria under various environmental conditions and to investigate the efficacy of ...


Natural And Value-Added Approaches For Pathogen Control, Zongyu Zhang Jan 2015

Natural And Value-Added Approaches For Pathogen Control, Zongyu Zhang

Graduate Theses and Dissertations

Infectious diseases caused by established foodborne pathogens, multidrug-resistant bacteria and opportunistic fungal pathogens pose serious threats to both public health and the economy. The aim of this work was to provide new approaches based on natural or value-added agricultural materials to address these important threats. Chapter 1 of this thesis provides a general introduction and description of how the work is organized. Chapter 2 reviews the literature related to our topics of research and Chapter 8 provides general conclusions. The remaining chapters report on the various projects that were conducted on the topics of natural and value-added approaches for pathogen ...


Impact Of Ddgs Feeding On The Composition Of Milk And Baby Swiss Cheese, Vaishnavi Manimanna Sankarlal Jan 2015

Impact Of Ddgs Feeding On The Composition Of Milk And Baby Swiss Cheese, Vaishnavi Manimanna Sankarlal

Graduate Theses and Dissertations

Late blowing in Swiss cheese, a result of unwanted gas production during ripening, is unacceptable to consumers, and causes economic loss to manufacturers. Cheese processors have raised concerns that feeding dried distillers' grains with soluble (DDGS) to cows leads to this defect, in part, because of Clostridial spores. Apart from that, in order to minimize bacterial contamination, antibiotics are being used in industrial ethanol fermentations. Residual antibiotics in DDGS could lead to inadvertent feeding of antibiotics to animals is also of concern. In this study, the effect of feeding DDGS to lactating dairy cows on composition and quality of milk ...


Enhancement Of Antimicrobial Activity Of Naturally Occuring Phenolic Compounds By Nano-Particle Mediated Delivery Against Listeria Monocytogenes, Escherichia Coli O157:H7, And Salmonella Typhimurium, Madhuram Ravichandran Dec 2014

Enhancement Of Antimicrobial Activity Of Naturally Occuring Phenolic Compounds By Nano-Particle Mediated Delivery Against Listeria Monocytogenes, Escherichia Coli O157:H7, And Salmonella Typhimurium, Madhuram Ravichandran

Theses and Dissertations

Food-borne illnesses are of major concern in the U.S. and worldwide. Salmonella,Listeria,E. coli O157:H7 continue to be some of the major foodborne pathogens. Recurring recalls due to these pathogens demand critical antimicrobial strategies to decontaminate the food through its procession from farm to fork. In our study, we combined the effectiveness of naturally occurring phenolic compounds individually, with/ without ethylenediamine tetraacetic acid (EDTA) and/or Nisin and nanoparticle delivery to improve the antimicrobial potential of the compounds against Listeria monocytogenes (L.m.), Salmonella Typhimurium (S.T.), and Escherichia coli O157:H7 (E.c.), in brain heart ...


Antimicrobial Activity Of Essential Oil Emulsions And Possible Synergistic Effect On Food Borne Pathogens, Varun Tahlan Jan 2014

Antimicrobial Activity Of Essential Oil Emulsions And Possible Synergistic Effect On Food Borne Pathogens, Varun Tahlan

Wayne State University Theses

The objective of this study was to evaluate the antimicrobial activity of essential oil emulsions against food borne pathogenic bacteria and determine potential applications. The oils used for this study were cinnamon, oregano, clove, thyme, rosemary, sage, bergamot, nutmeg, lemon grass and bay. Oil in water emulsions were prepared using Tween 80 as an emulsifying agent, with a stock oil concentration in the emulsions of 20,000 ppm. Essential oil emulsions were individually screened against E. coli (ATCC 25922), E. coli (ATCC 700927), L. monocytogens (ATCC 19115), L. innocua (ATCC 33090) and S. Typhimurium (ATCC 19585) using the broth micro ...


Aqueous Extracts Of Hibiscus Sabdariffa As Antimicrobials In Foods, Kristen Liane Higginbotham Dec 2013

Aqueous Extracts Of Hibiscus Sabdariffa As Antimicrobials In Foods, Kristen Liane Higginbotham

Masters Theses

Hibiscus sabdariffa L. is a tropical shrub species cultivated in multiple countries and is mainly produced for its red calyces that are used for a tea beverage. Aqueous, lyophilized extracts of Hibiscus were examined for their chemical composition and antimicrobial activity against Escherichia coli O157:H7, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and Listeria monocytogenes.

Lyophilized, dialyzed extracts of commercially aquired calyces were examined in microbiological medium and milk at various fat levels for antimicrobial activity against E. coli O157:H7 and S.aureus. Extracts were either filtered or autoclaved to sterilize and tested in microbiological medium. Autoclaved extracts were ...


Antimicrobial Efficacy Of Edible Soy Protein Isolate Films And Coatings Incorporated With Hop Ethanol Extract And The Influence On Shelf-Life And Sensory Attributes Of Bologna, Jamie R. G. Skudlarek Jan 2012

Antimicrobial Efficacy Of Edible Soy Protein Isolate Films And Coatings Incorporated With Hop Ethanol Extract And The Influence On Shelf-Life And Sensory Attributes Of Bologna, Jamie R. G. Skudlarek

Theses and Dissertations--Animal and Food Sciences

There is demand for improved security of refrigerated ready-to-eat meats. Antimicrobial edible films and coatings could function as an added barrier against post-processing contamination. Hops and hop extracts are known for their antimicrobial efficacy which is attributed to key antimicrobial components including humulones, lupulones, xanthohumol and various terpenoids. Yet, hop ethanol extract has not been studied as an antimicrobial to incorporate into edible protein films and/or coatings. The overall objective of this research was to evaluate hop ethanol extract as an antimicrobial agent incorporated into edible soy protein isolate (SPI) films and coatings, and the influence on the shelf-life ...


The Antimicrobial Activity Of Cold Pressed Terpeneless Valencia Orange Oil At Cold Temperatures, Sean Jeffrey Pendleton May 2011

The Antimicrobial Activity Of Cold Pressed Terpeneless Valencia Orange Oil At Cold Temperatures, Sean Jeffrey Pendleton

Theses and Dissertations

This research was undertaken to identify an antimicrobial for use during chilling in beef processing, including periods of temperature abuse, as well as to evaluate membrane filtration as means to remove essential oils from bacteria to prevent further antibacterial action. Cold pressed terpeneless Valencia orange oil was examined in combination with various temperatures (37°C, 10°C, and 4°C) to determine its antimicrobial activity against various strains of bacteria. The strains were tested using a ninety-six well microtiter plate method, with or without membrane filtration. The compound 2, 3, 5-triphenyl tetrazolium chloride was used as a growth indicator. Serial ...


Antimicrobial Properties Of Syringopeptin 25a And Rhamnolipids, Prerak T. Desai May 2006

Antimicrobial Properties Of Syringopeptin 25a And Rhamnolipids, Prerak T. Desai

All Graduate Theses and Dissertations

The increasing bacterial resistance to available antibiotics requires the search for new antibacterial compounds to be broadened. This study investigated the antimicrobial properties of two secondary metabolites from fluorescent pseudo monads -- syringopeptin 25A, a lipodepsipeptide produced by Pseudomonas syringae pv. syringae, and a rhamnolipid mixture produced by Pseudomonas aeruginosa. The rate of antimicrobial action was determined by monitoring the rate of uptake of propidium iodide during exposure to the compounds. Inhibition was also confirmed by the microbroth dilution method to determine the MI Cs. Both the compounds inhibited growth of Gram-positive organisms, including Mycobacterium smegmatis, staphylococci, and listeria. Inhibition of ...