Characterization of Amylose-lipid Complexes Derived from Different Wheat Varieties and their Susceptibility to Enzymatic Hydrolysis

2008 ◽  
Vol 14 (1) ◽  
pp. 29-37 ◽  
Author(s):  
I. Kwaśniewska-Karolak ◽  
E. Nebesny ◽  
J. Rosicka-Kaczmarek
Keyword(s):  
Enzymatic Hydrolysis ◽  
Polymorphic Form ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Lipid Complex ◽  
Wheat Varieties ◽  
Reversible Dissociation ◽  
Starch Gel ◽  
Considerable Degradation

Starches from eight wheat varieties were analyzed for contents of dry matter, protein, pentosans, apparent and total amylose, total lipids, starch lipids, phosphorus, lysophospholipids and amylose-lipid complex (AML). Processes of starch gelatinization, reversible dissociation of AMLs and its susceptibility to degradation by α-amylase were monitored by differential scanning calorimetry (DSC). Degree of crystallinity of starches were evaluated based on X-ray diffraction pattern. Starches from different wheat varieties show some slight differences in terms of chemical composition, thermal properties and susceptibility to enzymatic hydrolysis. Endotherms and exotherms of most starch samples obtained by DSC contained single peaks, which indicated that AML complexes existed in one polymorphic form. Only AMLs formed by amylose from Symfonia cultivar was reflected by the double-peak exotherm on cooling of starch gel. Our studies showed that there was no correlation between AML content and enthalpy of its degradation in native starch. During enzymatic hydrolysis of starch AML complex in all examined starches underwent considerable degradation. Enthalpies of dissociation of AMLs, which remained after amylolysis were significantly lowered (80—90%) as compared to that of undigested starch. The susceptibility of AMLs to degradation by α-amylase did not depend on its amount (based on calculation from LPLs), but probably on its structure.

scholarly journals Biobased Engineering Thermoplastics: Poly(butylene 2,5-furandicarboxylate) Blends

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 937 ◽  
Author(s):  
Niki Poulopoulou ◽  
George Kantoutsis ◽  
Dimitrios N. Bikiaris ◽  
Dimitris S. Achilias ◽  
Maria Kapnisti ◽  
...  
Keyword(s):  
Renewable Resources ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Reactive Blending ◽  
Scanning Calorimetry ◽  
Melt Polycondensation ◽  
Poly Ethylene Terephthalate ◽  
Furandicarboxylic Acid ◽  
Poly Ethylene ◽  
Poly Propylene

Poly(butylene 2,5-furandicarboxylate) (PBF) constitutes a new engineering polyester produced from renewable resources, as it is synthesized from 2,5-furandicarboxylic acid (2,5-FDCA) and 1,4-butanediol (1,4-BD), both formed from sugars coming from biomass. In this research, initially high-molecular-weight PBF was synthesized by applying the melt polycondensation method and using the dimethylester of FDCA as the monomer. Furthermore, five different series of PBF blends were prepared, namely poly(l-lactic acid)–poly(butylene 2,5-furandicarboxylate) (PLA–PBF), poly(ethylene terephthalate)–poly(butylene 2,5-furandicarboxylate) (PET–PBF), poly(propylene terephthalate)–poly(butylene 2,5-furandicarboxylate) (PPT–PBF), poly(butylene 2,6-naphthalenedicarboxylate)-poly(butylene 2,5-furandicarboxylate) (PBN–PBF), and polycarbonate–poly(butylene 2,5-furandicarboxylate) (PC–PBF), by dissolving the polyesters in a trifluoroacetic acid/chloroform mixture (1/4 v/v) followed by coprecipitation as a result of adding the solutions into excess of cold methanol. The wide-angle X-ray diffraction (WAXD) patterns of the as-prepared blends showed that mixtures of crystals of the blend components were formed, except for PC which did not crystallize. In general, a lower degree of crystallinity was observed at intermediate compositions. The differential scanning calorimetry (DSC) heating scans for the melt-quenched samples proved homogeneity in the case of PET–PBF blends. In the remaining cases, the blend components showed distinct Tgs. In PPT–PBF blends, there was a shift of the Tgs to intermediate values, showing some partial miscibility. Reactive blending proved to improve compatibility of the PBN–PBF blends.

scholarly journals Hemp Fibre Reinforced Poly(Lactic Acid) Composites

2007 ◽  
Vol 29-30 ◽  
pp. 337-340 ◽  
Author(s):  
M.A. Sawpan ◽  
K.L. Pickering ◽  
Alan Fernyhough
Keyword(s):  
Lactic Acid ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hemp Fibre ◽  
Reinforcing Material ◽  
Fibre Loading ◽  
The Degree Of Crystallinity

The potential of hemp fibre as a reinforcing material for Poly(lactic acid) (PLA) was investigated. Good interaction between hemp fibre and PLA resulted in increases of 100% for Young’s modulus and 30% for tensile strength of composites containing 30 wt% fibre. Different predictive ‘rule of mixtures’ models (e.g. Parallel, Series and Hirsch) were assessed regarding the dependence of tensile properties on fibre loading. Limited agreement with models was observed. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) studies showed that hemp fibre increased the degree of crystallinity in PLA composites.

scholarly journals Mechanochemical Formation of Racemic Praziquantel Hemihydrate with Improved Biopharmaceutical Properties

Pharmaceutics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 289
Author(s):  
Debora Zanolla ◽  
Dritan Hasa ◽  
Mihails Arhangelskis ◽  
Gabriela Schneider-Rauber ◽  
Michele R. Chierotti ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Polymorphic Form ◽  
In Vitro Tests ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Experimental Conditions ◽  
Intrinsic Dissolution ◽  
Intrinsic Dissolution Rate ◽  
X Ray ◽  
Enhanced Solubility

Praziquantel (PZQ) is the first-line drug used against schistosomiasis, one of the most common parasitic diseases in the world. A series of crystalline structures including two new polymorphs of the pure drug and a series of cocrystals of PZQ have been discovered and deposited in the Cambridge Structural Database (CSD). This work adds to the list of multicomponent forms of PZQ a relevant example of a racemic hemihydrate (PZQ-HH), obtainable from commercial PZQ (polymorphic Form A) through mechanochemistry. Noteworthy, the formation of the new hemihydrate strongly depends on the initial polymorphic form of PZQ and on the experimental conditions used. The new PZQ-HH has been fully characterized by means of HPLC, Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Hot-Stage Microscopy (SEM), Powder X-Ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), FT-IR, polarimetry, solid-state NMR (SS-NMR), solubility and intrinsic dissolution rate (IDR), and in vitro tests on Schistosoma mansoni adults. The crystal structure was solved from the powder X-ray diffraction pattern and validated by periodic-DFT calculations. The new bioactive hemihydrate was physically stable for three months and showed peculiar biopharmaceutical features including enhanced solubility and a double intrinsic dissolution rate in water in comparison to the commercially available PZQ Form A.

Study of the structure and thermal characteristics of nanocomposites based on polyvinyl alcohol and intercalated montmorillonite

2019 ◽  
pp. 089270571987919
Author(s):  
Volodymyr Krasinskyi ◽  
Ivan Gajdos ◽  
Oleh Suberlyak ◽  
Viktoria Antoniuk ◽  
Tomasz Jachowicz
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Acrylic Acid ◽  
Polyvinyl Alcohol ◽  
Thermal Characteristics ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Degree Of Crystallinity

The structure and thermal characteristics of nanocomposites based on polyvinyl alcohol (PVA) and montmorillonite (MMT) intercalated with polyvinylpyrrolidone were investigated by X-ray diffraction analysis and differential scanning calorimetry. The modification of PVA with intercalated MMT reduces the degree of crystallinity of the resulting nanocomposites but significantly increases their thermal stability. Under ultrasound, the intercalated MMT was completely distributed in a PVA solution and formed a monocrystalline structure. Films based on PVA with modified MMT were cross-linked at 110°C in the presence of 5 wt% acrylic acid and 0.5 wt% Ferrous(II) sulfate as an initiator. The formed films have a homogeneous cross-linked structure.

scholarly journals Photocatalytic and adsorption properties of TiO2-pillared montmorillonite obtained by hydrothermally activated intercalation of titanium polyhydroxo complexes

2018 ◽  
Vol 9 ◽  
pp. 364-378 ◽  
Author(s):  
Mikhail F Butman ◽  
Nikolay L Ovchinnikov ◽  
Nikita S Karasev ◽  
Nataliya E Kochkina ◽  
Alexander V Agafonov ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Nitrogen Adsorption ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
New Approach ◽  
Pillared Montmorillonite ◽  
Degussa P25 ◽  
Adsorption Desorption ◽  
High Degree

We report on a new approach for the synthesis of TiO2-pillared montmorillonite, where the pillars exhibit a high degree of crystallinity (nanocrystals) representing a mixture of anatase and rutile phases. The structures exhibit improved adsorption and photocatalytic activity as a result of hydrothermally activated intercalation of titanium polyhydroxo complexes (i.e., TiCl4 hydrolysis products) in a solution with a concentration close to the sol formation limit. The materials, produced at various annealing temperatures from the intercalated samples, were characterized by infrared spectroscopy, differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA), X-ray diffraction, dynamic light scattering (DLS) measurements, and liquefied nitrogen adsorption/desorption. The photocatalytic activity of the TiO2-pillared materials was studied using the degradation of anionic (methyl orange, MO) and cationic (rhodamine B, RhB) dyes in water under UV irradiation. The combined effect of adsorption and photocatalysis resulted in removal of 100% MO and 97.5% RhB (with an initial concentration of 40 mg/L and a photocatalyst-sorbent concentration of 1 g/L) in about 100 minutes. The produced TiO2-pillared montmorillonite showed increased photocatalytic activity as compared to the commercially available photocatalyst Degussa P25.

The Synthesis and Crystallization of Poly(vinylidene fluoride) in Supercritical CO2

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Zhendong Shi ◽  
Zhen Zheng ◽  
Xiaoli Su ◽  
Xinling Wang
Keyword(s):  
Vinylidene Fluoride ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Good Solubility ◽  
Poly Vinylidene Fluoride ◽  
Ft Ir ◽  
Application Fields ◽  
Crystallization Mode

AbstractA series of poly(vinylidene fluoride)s (PVDFs) is synthesized in supercritical carbon dioxide (sc-CO2). The influences of polymerization pressure, molecular weight distribution and H-H defect concentration on the crystallization of PVDF have been studied in combination with differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXRD) and Fourier transform infrared spectroscopy (FT-IR) measurements. The result shows that the morphology, molecular weights, polydispersity and head-to-head (H-H) defect concentrations of the PVDFs are affected by the reaction pressure and good solubility generated from sc-CO2. Especially, the sc-CO2 polymerization has greatly improved the crystallization mode of the obtained PVDFs such as the complete degree of crystallinity, crystallinity and the crystal phase. This will create more comprehensive application fields for PVDF.

scholarly journals Development and Characterization of Novel Polyurethane Films Impregnated with Tolfenamic Acid for Therapeutic Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Hilal Istanbullu ◽  
Sofia Ahmed ◽  
Muhammad Ali Sheraz ◽  
Ihtesham ur Rehman
Keyword(s):  
Polymer Concentration ◽  
Tolfenamic Acid ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Release Studies ◽  
Evaporation Technique ◽  
Crystallinity Changes ◽  
The Degree Of Crystallinity

The present study deals with the preparation of polyurethane (PU) films impregnated with a nonsteroidal anti-inflammatory drug, tolfenamic acid (TA). Solvent evaporation technique has been employed for the preparation of TA-PU films in two different ratios of 1 : 2 and 1 : 5 in Tetrahydrofuran (THF) or THF-ethanol mixtures. The prepared films were characterized using X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and release studies. The results indicate transformation of crystalline TA to its amorphous form. The degree of crystallinity changes both by increasing the polymer concentration and solvent used for the film preparations. The release profiles of TA were also found to be affected, showing a decrease from approximately 50% to 25% from 1 : 2 to 1 : 5 ratios, respectively.

scholarly journals The Usefulness of X-ray Diffraction and Thermal Analysis to Study Dietary Supplements Containing Iron

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 197
Author(s):  
Izabela Jendrzejewska ◽  
Robert Musioł ◽  
Tomasz Goryczka ◽  
Ewa Pietrasik ◽  
Joanna Klimontko ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Melting Point ◽  
Dietary Supplements ◽  
Polymorphic Form ◽  
Food Supplements ◽  
X Ray Diffraction ◽  
Iron Compounds ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Amorphous Compounds

X-ray powder diffraction (XRPD) and thermal analysis (differential scanning calorimetry/derivative of thermogravimetry (DSC/DTG)) are solid-state techniques that can be successfully used to identify and quantify various chemical compounds in polycrystalline mixtures, such as dietary supplements or drugs. In this work, 31 dietary supplements available on the Polish market that contain iron compounds, namely iron gluconate, fumarate, bisglycinate, citrate and pyrophosphate, were evaluated. The aim of the work was to identify iron compounds declared by the manufacturer as food supplements and to try to verify compliance with the manufacturer’s claims. Studies performed by X-ray and thermal analysis confirmed that crystalline iron compounds (iron (II) gluconate, iron (II) fumarate), declared by the manufacturers, were present in the investigated dietary supplements. Iron (II) bisglycinate proved to be semi-crystalline. However, depending on the composition of the formulation, it was possible to identify this compound in the tested supplements. For amorphous iron compounds (iron (III) citrate and iron (III) pyrophosphate), the diffraction pattern does not have characteristic diffraction lines. Food supplements containing crystalline iron compounds have a melting point close to the melting point of pure iron compounds. The presence of excipients was found to affect the shapes and positions of the endothermic peaks significantly. Widening of endothermic peaks and changes in their position were observed, as well as exothermic peaks indicating crystallization of amorphous compounds. Weight loss was determined for all dietary supplements tested. Analysis of the DTG curves showed that the thermal decomposition of most food supplements takes place in several steps. The results obtained by a combination of both simple, relatively fast and reliable XRPD and DSC/DTG methods are helpful in determining phase composition, pharmaceutical abnormalities or by detecting the presence of the correct polymorphic form.

Polymorphic forms of bendamustine hydrochloride: crystal structure, thermal properties and stability at ambient conditions

2019 ◽  
Vol 75 (6) ◽  
pp. 933-941
Author(s):  
Pablo Gaztañaga ◽  
Ricardo Baggio ◽  
Daniel Roberto Vega
Keyword(s):  
Crystal Structure ◽  
Fusion Rule ◽  
Polymorphic Form ◽  
Heat Of Fusion ◽  
High Humidity ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Molecular Conformations ◽  
Polymorphic Forms

Crystallographic, thermal and stability analyses are presented of three different anhydrated forms of bendamustine hydrochloride [(I), (III) and (IV)] and a fourth, monohydrated one (II). Since form (I) presents the higher melting point and the higher heat of fusion, according to the `heat of fusion' rule it should be the most stable in thermodynamic terms [Burger & Ramberger (1979). Mikrochim. Acta, 72, 259–271], though it is unstable in high-humidity conditions. The monohydrate structure (II), in turn, dehydrates by heating and topotactically transform into anhydrate (III). This latter form appears as less stable than anhydrate (I), to which it is linked via a monotropic relationship. For these three different forms, the crystal structure has been determined by single crystal X-ray diffraction. The crystal structures and molecular conformations of forms (II) and (III) are quite similar, as expected from the topotactic transformation linking them; furthermore, under high-humidity conditions, form (III) shows changes compatible with a transformation into form (II) within 24 h. The crystal structure of form (I) is different from the other two. The remaining polymorphic form (IV) could only be obtained as a powder, from which its crystalline structure could not be determined. The relative thermodynamic stability of the different crystalline forms was determined by differential scanning calorimetry and thermogravimetrical studies, and their stability under different humidity conditions analysed.

Physicochemical Properties of Porous Starches from Different Botanical Origin

2010 ◽  
Vol 159 ◽  
pp. 363-370
Author(s):  
Hua Xi Xiao ◽  
Qin Lu Lin ◽  
Yue Wu ◽  
Wei Tian ◽  
Wei Wu
Keyword(s):  
Potato Starch ◽  
Enzyme Hydrolysis ◽  
Degree Of Crystallinity ◽  
Rice Starch ◽  
Adsorptive Capacity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Potato Starches ◽  
The Degree Of Crystallinity

Rice, maize and potato starches were hydrolyzed by amylase to obtain porous starches as final product. The adsorptive capacity, desorbed rates, degree of crystallinity and retrogradation properties of native and porous starches were investigated. The results showed that porous starches had the stronger adsorptive capacity and slower desorbed rate compared with native starches. In the three starch materials, the adsorptive capacity of rice starch for liquids was the strongest; the adsorptive capacity of potato starch for liquids was the weakest. the more flavors adsorbed, the more flavors desorbed. X-ray diffraction showed that Enzyme hydrolysis did not result in any significant changes in the degree of crystallinity of starch. The porous starches exhibited lower tendency of retrogradation as assessed by differential scanning calorimetry (DSC).

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