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Articles 1 - 16 of 16
Full-Text Articles in Food Chemistry
Enantioselectivity Of The Photochemical Continuous-Flow Isomerization Of Humulones, Gregory M. Giovine, Trevor Smith, Bruce Hamper
Enantioselectivity Of The Photochemical Continuous-Flow Isomerization Of Humulones, Gregory M. Giovine, Trevor Smith, Bruce Hamper
Undergraduate Research Symposium
Humulones, the primary natural product present in the historically significant hop flower, represent a largely unexplored candidate for structure-based pharmaceutical design. Showing promising biological activity as an anti-bacterial and anti-inflammatory agent, humulones are of interest both for their bioactive properties and for their long-established tolerability and natural abundance. Humulones undergo a characteristic isomerization reaction, where the six-membered substituted phloroglucinol ring contracts to a five-membered ring isohumulone, under a variety of conditions, including those enabled by brewing conditions (thermal, metal-catalyzed) and by exposure to UV light. Optimization of the photocatalyzed isomerization of n-humulone to n-isohumulone in flow conditions resulted in a …
Amorphous Calcium Phosphate Maintains Casein Microarchitecture While Modulating Bacterial Growth Kinetics, Vuk Uskoković, Michael Ibba, Lorenzo Eugenio Leiva
Amorphous Calcium Phosphate Maintains Casein Microarchitecture While Modulating Bacterial Growth Kinetics, Vuk Uskoković, Michael Ibba, Lorenzo Eugenio Leiva
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Casein, the primary source of protein in ruminant milk, represents a family of proteins that self-assemble into globules composed of finer spherical subunits and stabilized by calcium phosphate (CP) nanoparticles. These globules act as holdase-type chaperones for unfolded or partially folded proteins, preventing their aggregation. Simultaneously, by integrating CP nanoparticles, they enable the bioavailability of calcium and phosphate beyond their solubility limits, thereby enhancing the nutritional value of milk. Using a range of physicochemical and biological characterization techniques, including scanning and transmission electron microscopy, organic and inorganic elemental analyses, SDS-PAGE, and vibrational, UV/Vis and NMR spectroscopies, it is demonstrated that …
Photoflow Synthesis And Characterization Of Cis- And Trans-N-Isohumulone, Gregory M. Giovine, Bradley Gallow, Trevor Smith, Bruce Hamper
Photoflow Synthesis And Characterization Of Cis- And Trans-N-Isohumulone, Gregory M. Giovine, Bradley Gallow, Trevor Smith, Bruce Hamper
Undergraduate Research Symposium
Previously published efforts by the Hamper group demonstrated the viability of photochemistry in the isomerization of n-humulone to n-isohumulone. Photochemical isomerization reactions of n-humulone performed under 400nm light over 8 hours resulted in high yields (84% reported) of largely trans-n-isohumulone (>95%). These promising results invited further examination of the photochemical process and the application of photoflow procedure. Herein we report the beginnings of a comprehensive slate of n-humulone isomerization reactions performed under iterative photoflow conditions.
High Order Structures Formed By The Natural Aromatic Amino Acids, Gabriel Alexander Kupovics, Zeina Alraawi
High Order Structures Formed By The Natural Aromatic Amino Acids, Gabriel Alexander Kupovics, Zeina Alraawi
Inquiry: The University of Arkansas Undergraduate Research Journal
Excessive concentrations of the natural aromatic amino acids phenylalanine and tyrosine are characteristic of the severe genetic abnormalities known as phenylketonuria (PKU) and tyrosinemia, respectively. Within this context, this feature article authenticates claims that tryptophan can form amyloid-like supramolecular structures in vitro and is the first to propose potential mechanisms of tryptophan self-assembly, including hydrophobic and electrostatic interactions. Thioflavin T (ThT) fluorescence kinetics and transmission electron microscopy (TEM) data suggest the formation of amyloid-like fibrillar structures by natural aromatic amino acids in vitro. Additionally, the propensity of amino acid aggregation increases in the presence of sodium dodecyl sulfate (SDS). The …
Application Of Mass Spectrometry For Characterization Of Plant-Based Phenolics And Alkaloids, Masoumeh Dorrani
Application Of Mass Spectrometry For Characterization Of Plant-Based Phenolics And Alkaloids, Masoumeh Dorrani
Theses and Dissertations--Chemistry
Plant-derived compounds have the potential to produce value-added compounds with a variety of applications. For example, the lignin part of the lignocellulosic biomass, produced in large quantities as waste from the paper and pulp industries, is a rich source of phenolics with potential applications in the renewable energy sector, pharmaceutical, and chemical industries. On the other hand, plant alkaloids are the primary source for developing plant-derived therapeutics. Unfortunately, the recalcitrant nature of plant cell walls, low extraction yields of small secondary metabolites, and the lack of effective analytical methods for a rapid and accurate identification of plant-based compounds and plant’s …
The Chemistry Of Fermentation As It Relates To The Art Of Winemaking, Olivia Cochran
The Chemistry Of Fermentation As It Relates To The Art Of Winemaking, Olivia Cochran
Symposium of Student Scholars
The process of fermentation can be traced back to the beginning of civilization. Countries, over time, have learned this scientific process and turned it into the backbone of their culture through the making and manufacturing of wine. While climate-change and global-warming have impacted the commercial marketability of wine, the scientific process has remained constant. This undergraduate project analyses the production, fermentation and analytical approach of producing high quality wine. Beginning from the picking of grapes, to testing the acidity through a series of titrations, winemaking is truly where science and art collide.
Ruggedized Color Measurement For Beer, Wort, And Malt, Roger Barth, Randall H. Reiger, Yuki Kim
Ruggedized Color Measurement For Beer, Wort, And Malt, Roger Barth, Randall H. Reiger, Yuki Kim
Chemistry Faculty Publications
The standard instrument for measuring malt, wort, and beer color is the spectrophotometer. Spectrophotometers are not rugged; they have critically aligned collimators, monochromators, lenses, slits, and mirrors that make them difficult to use and maintain in a production environment. Our research shows that wort and beer color can be measured accurately with rugged equipment based on light emitting diodes (LEDs) with results in agreement with those of a spectrophotometer. Two or more colored diodes were used. LED-based apparatus does not require critical alignment, is not highly sensitive to environmental conditions such as temperature, moisture, dust, and vibration, and can be …
Crystal Structure Of Zymonic Acid And A Redetermination Of Its Precursor, Pyruvic Acid, Dominik Heger, Alexis J. Eugene, Sean R. Parkin, Marcelo I. Guzman
Crystal Structure Of Zymonic Acid And A Redetermination Of Its Precursor, Pyruvic Acid, Dominik Heger, Alexis J. Eugene, Sean R. Parkin, Marcelo I. Guzman
Chemistry Faculty Publications
The structure of zymonic acid (systematic name: 4-hydroxy-2-methyl-5-oxo-2,5-dihydrofuran-2-carboxylic acid), C6H6O5, which had previously eluded crystallographic determination, is presented here for the first time. It forms by intramolecular condensation of parapyruvic acid, which is the product of aldol condensation of pyruvic acid. A redetermination of the crystal structure of pyruvic acid (systematic name: 2-oxopropanoic acid), C3H4O3, at low temperature (90 K) and with increased precision, is also presented [for the previous structure, see: Harata et al. (1977). Acta Cryst. B33, 210–212]. In zymonic acid, the hydroxylactone ring …
A Galactomannoglucan Derived From Agaricus Brasiliensis: Purification, Characterization And Macrophage Activation Via Mapk And Ikappab/Nfkappab Pathways, Yanqing Zhang, Danting Liu, Leilei Fang, Xiaotong Zhao, Aimin Zhou, Junbo Xie
A Galactomannoglucan Derived From Agaricus Brasiliensis: Purification, Characterization And Macrophage Activation Via Mapk And Ikappab/Nfkappab Pathways, Yanqing Zhang, Danting Liu, Leilei Fang, Xiaotong Zhao, Aimin Zhou, Junbo Xie
Chemistry Faculty Publications
In this study, a novel galactomannoglucan named as TJ2 was isolated from Agaricus brasiliensis with microwave extraction, macroporous resin, ion exchange resin and high resolution gel chromatography. TJ2 is composed of glucose, mannose and galactose in the ratio 99.2:0.2:0.6. Infrared spectra (IR), methylation analysis and nuclear magnetic resonance spectra indicated that TJ2 mainly contained a b-(1?3) – linked glucopyranosyl backbone. Interestingly, TJ2 significantly promoted RAW264.7 cell proliferation, and was able to activate the cells to engulf E. coli. In addition, TJ2 induced the expression of Interleukin 1b (IL-1b), Interleukin 6 (IL-6), tumor necrosis factor a (TNF-a) and cyclooxygenase-2 (Cox-2) in …
Reactivity Of Ketyl And Acetyl Radicals From Direct Solar Actinic Photolysis Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman
Reactivity Of Ketyl And Acetyl Radicals From Direct Solar Actinic Photolysis Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman
Chemistry Faculty Publications
The variable composition of secondary organic aerosols (SOA) contributes to the large uncertainty for predicting radiative forcing. A better understanding of the reaction mechanisms leading to aerosol formation such as for the photochemical reaction of aqueous pyruvic acid (PA) at λ ≥ 305 nm can contribute to constrain these uncertainties. Herein, the photochemistry of aqueous PA (5-300 mM) continuously sparged with air is re-examined in the laboratory under comparable irradiance at 38° N at noon on a summer day. Several analytical methods are employed to monitor the time series of the reaction, including (1) the derivatization of carbonyl (C═O) functional …
Characterization Of Cellulase Enzyme Inhibitors Formed During The Chemical Pretreatments Of Rice Straw, Kalavathy Rajan
Characterization Of Cellulase Enzyme Inhibitors Formed During The Chemical Pretreatments Of Rice Straw, Kalavathy Rajan
Graduate Theses and Dissertations
Production of fuels and chemicals from a renewable and inexpensive resource such as lignocellulosic biomass is a lucrative and sustainable option for the advanced biofuel and bio-based chemical platform. Agricultural residues constitute the bulk of potential feedstock available for cellulosic fuel production. On a global scale, rice straw is the largest source of agricultural residues and is therefore an ideal crop model for biomass deconstruction studies. Lignocellulosic biofuel production involves the processes of biomass conditioning, enzymatic saccharification, microbial fermentation and ethanol distillation, and one of the major factors affecting its techno-economic feasibility is the biomass recalcitrance to enzymatic saccharification. Preconditioning …
Oxidative Stability Of Conjugated Linoleic Acid Rich Soy Oil Obtained By Heterogeneous Ruthenium Catalysis, Saurabh Ravindra Lele
Oxidative Stability Of Conjugated Linoleic Acid Rich Soy Oil Obtained By Heterogeneous Ruthenium Catalysis, Saurabh Ravindra Lele
Graduate Theses and Dissertations
Conjugated linoleic acid (CLA) has multiple health benefits but it is difficult to obtain sufficient CLA in a healthy diet to obtain the clinical effects. A CLA rich-soy oil (CLARSO) with up to 20% CLA has been produced by heterogenous catalysis but no studies of its oxidative stability have been reported. CLARSO and soy oil primary and secondary oxidation products were measured at 50oC in the dark. The CLARSO was less stable than soy oil but adsorption bleaching improved its oxidative stability. However, induction times were dependent on the analytical method used. Fatty acid oxidation kinetics was determined by measuring …
Effects Of Xanthan/Locust Bean Gum Mixtures On The Physicochemical Properties And Oxidative Stability Of Whey Protein Stabilized Oil-In-Water Emulsions, Goutham Puli
Masters Theses & Specialist Projects
Scientific evidence shows that dietary intake of the omega-3 polyunsaturated fatty acids is beneficial to human health. Fish oil is a rich source of omega-3 fatty acids. However, fish oil with high levels of omega-3 PUFA is very susceptible to oxidative deterioration during storage. The objective of this study was to investigate the effect of xanthan gum (XG)-locust bean gum (LBG) mixtures on the physicochemical properties of whey protein isolate (WPI) stabilized oil-in-water (O/W) emulsions containing 20% v/v menhaden oil. The O/W emulsions containing XG/LBG mixtures were compared to emulsions with either XG or LBG alone. The emulsions were prepared …
Using Stable Isotope Analysis Of Zooplankton To Document Trophic And Biogeochemical Changes In The San Francisco Estuary, Steven C. Westbrook, Julien Moderan
Using Stable Isotope Analysis Of Zooplankton To Document Trophic And Biogeochemical Changes In The San Francisco Estuary, Steven C. Westbrook, Julien Moderan
STAR Program Research Presentations
Zooplankton represent a vital link between phytoplankton and fish, like the endangered Delta Smelt. Human interferences (nitrates from waste water, flow alteration, invasive species introduction…) have altered the structure of the San Francisco Estuary (SFE) ecosystem. We use stable isotope analysis to improve our knowledge of the planktonic food web in the SFE and gain insights into its evolution over the past decades. We use the ratios of certain isotopes (Nitrogen, Carbon, Sulfur, etc.) in different species of zooplankton to tell us what it is feeding on as well as the trophic level it feeds in. My research focused on …
New Palm Oil Products By Enzymatic Interesterification And Dry Fractionation., Saw Mei Huey
New Palm Oil Products By Enzymatic Interesterification And Dry Fractionation., Saw Mei Huey
Student Works (2010-2019)
Palm olein is one of the major palm oil products that domestically and industrially used as cooking or frying oil. Palm olein tends to crystallize at low temperature that limits its usage in temperate countries. In spite of various nutritional studies, palm olein is also not well considered as recommended choice due to its higher saturation content. Against these factors, there is a need to reduce its saturation content. In this study, the saturation content in palm olein was reduced through the combination of enzymatic interesterification and dry fractionation. Enzymatic interesterification allows interchanging of acyl groups between and within triacylglycerols …
The Isolation And Identification Of Polyphenolics From Grape Seeds And Their Activity Towards Specific Cell Lines, Joseph A. Reddy
The Isolation And Identification Of Polyphenolics From Grape Seeds And Their Activity Towards Specific Cell Lines, Joseph A. Reddy
Chemistry & Biochemistry Theses & Dissertations
Grape seed extract is being marketed in France for cardiovascular use and skin care. The active constituents of both these drugs are certain polyphenols called procyanidins. A similar seed extract has now been obtained from Virginia Chardonnay grape seeds. Ten of the major components in this extract have been isolated in their pure form by the semi-preparative HPLC separation on a YMC ODS-AQ (Octadecylsilane-AQ) column. The ODS-Aq column has been shown to have a better resolving capacity compared to the Spherisorb ODS (Octadecylsilane) column previously described in the literature. This has been attributed to the ODSAQ support which has both …