24 research outputs found

    An Insight into the Gelatinization Properties Influencing the Modified Starches Used in Food Industry: A review

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    AbstractNative starch is subjected to various forms of modification to improve its structural, mechanical, and thermal properties for wider applications in the food industry. Physical, chemical, and dual modifications have a substantial effect on the gelatinization properties of starch. Consequently, this review explores and compares the different methods of starch modification applicable in the food industry and their effect on the gelatinization properties such as onset temperature (To), peak gelatinization temperature (Tp), end set temperature (Tc), and gelatinization enthalpy (ΔH), studied using differential scanning calorimetry (DSC). Chemical modifications including acetylation and acid hydrolysis decrease the gelatinization temperature of starch whereas cross-linking and oxidation result in increased gelatinization temperatures. Common physical modifications such as heat moisture treatment and annealing also increase the gelatinization temperature. The gelatinization properties of modified starch can be applied for the improvement of food products such as ready-to-eat, easily heated or frozen food, or food products with longer shelf life

    Width dependence of the 0.5 × (2e2/h) conductance plateau in InAs quantum point contacts in presence of lateral spin-orbit coupling

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    The evolution of the 0.5Go (Go = 2e2/h) conductance plateau and the accompanying hysteresis loop in a series of asymmetrically biased InAs based quantum point contacts (QPCs) in the presence of lateral spin-orbit coupling (LSOC) is studied using a number of QPCs with varying lithographic channel width but fixed channel length. It is found that the size of the hysteresis loops is larger for QPCs of smaller aspect ratio (QPC channel width/length) and gradually disappears as their aspect ratio increases. The physical mechanisms responsible for a decrease in size of the hysteresis loops for QPCs with increasing aspect ratio are: (1) multimode transport in QPCs with larger channel width leading to spin-flip scattering events due to both remote impurities in the doping layer of the heterostructure and surface roughness and impurity (dangling bond) scattering on the sidewalls of the narrow portion of the QPC, and (2) an increase in carrier density resulting in a screening of the electron-electron interactions in the QPC channel. Both effects lead to a progressive disappearance of the net spin polarization in the QPC channel and an accompanying reduction in the size of the hysteresis loops as the lithographic width of the QPC channel increases

    Inhibition of Na+/K+- and Ca2+-ATPase activities by phosphotetradecavanadate

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    Polyoxometalates (POMs) are promising inorganic inhibitors for P-type ATPases. The experimental models used to study the effects of POMs on these ATPases are usually in vitro models using vesicles from several membrane sources. Very recently, some polyoxotungstates, such as the Dawson anion [P2W18O62]6-, were shown to be potent P-type ATPase inhibitors; being active in vitro as well as in ex-vivo. In the present study we broaden the spectrum of highly active inhibitors of Na+/K+-ATPase from basal membrane of epithelial skin to the bi-capped Keggin-type anion phosphotetradecavanadate Cs5.6H3.4PV14O42 (PV14) and we confront the data with activity of other commonly encountered polyoxovanadates, decavanadate (V10) and monovanadate (V1). The X-ray crystal structure of PV14 was solved and contains two trans-bicapped α-Keggin anions HxPV14O42(9-x)-. The anion is built up from the classical Keggin structure [(PO4)@(V12O36)] capped by two [VO] units. PV14 (10 μM) exhibited higher ex-vivo inhibitory effect on Na+/K+-ATPase (78%) than was observed at the same concentrations of V10 (66%) or V1 (33%). Moreover, PV14 is also a potent in vitro inhibitor of the Ca2+-ATPase activity (IC50 5 μM) exhibiting stronger inhibition than the previously reported activities for V10 (15 μM) and V1 (80 μM). Putting it all together, when compared both P-typye ATPases it is suggested that PV14 exibited a high potential to act as an in vivo inhibitor of the Na+/K+-ATPase associated with chloride secretion.FCT, Foundation for Science and Technology (UID/Multi/04326/2013) ; (SFRH/BSAB/129821/2017) Austrian Science Fund (FWF) (P27534) (M2200) Council of Scientific & Industrial Research (CSIR) (01(2906)/17/EMR-II) Grant Agency of the Ministry of Education of the Slovak Republic and Slovak Academy of Sciences VEGA (1/0507/17)info:eu-repo/semantics/publishedVersio

    Hervé- and Krebs-Type Magnetic Polyoxometalate Dimers

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    Lacunary polyoxometalates (POMs) are negatively charged metal–oxo clusters, formally obtained from plenary topologies via fragment removal. Owing to the fragment removal, the lacunary POMs archetypes are rich in nucleophilic terminal oxo ligands, making them suitable for post-synthetic coordination with various heterometals. Trilacunary heteropolytungstates (hetero-POTs) based on bowl-shaped {W9O30} framework incorporating a central lone-pair containing {XO3} hetergroup (X = AsIII, SbIII, and BiIII) function as all-inorganic scaffolds that in the presence of d-block metal cations typically construct sandwich-like dimers of Hervé and/or Krebs. Herein we review the preparative approaches, as well as compositional and magnetic versatility of the constructed Hervé- and Krebs-type dimers and discuss prospective uses as POMtronics

    Hervé- and Krebs-Type Magnetic Polyoxometalate Dimers

    No full text
    Lacunary polyoxometalates (POMs) are negatively charged metal–oxo clusters, formally obtained from plenary topologies via fragment removal. Owing to the fragment removal, the lacunary POMs archetypes are rich in nucleophilic terminal oxo ligands, making them suitable for post-synthetic coordination with various heterometals. Trilacunary heteropolytungstates (hetero-POTs) based on bowl-shaped {W9O30} framework incorporating a central lone-pair containing {XO3} hetergroup (X = AsIII, SbIII, and BiIII) function as all-inorganic scaffolds that in the presence of d-block metal cations typically construct sandwich-like dimers of Hervé and/or Krebs. Herein we review the preparative approaches, as well as compositional and magnetic versatility of the constructed Hervé- and Krebs-type dimers and discuss prospective uses as POMtronics

    One-Pot Synthesis of Polyoxometalate Decorated Polyindole for Energy Storage Supercapacitors

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    The demand for energy storage supercapacitor devices has increased interest in completing all innovative technologies and renewable energy requirements. Here, we report a simple method of two polyoxomolybdate (H4[PVMo11O40] and H5[PV2Mo10O40]) doped polyindole (PIn) composites for electrochemical supercapacitors. The interactions between polyoxomolybdates and PIn were measured by Fourier transform infrared spectroscopy (FTIR), and powder XRD, and stability was measured by thermogravimetry. The field emission scanning microscopy (FESEM) was employed to investigate the morphology of the materials. The electrochemical measurements show that the PIn/PV2Mo10 electrode exhibits a higher capacitance of 198.09 F/g with an energy density of 10.19 Wh/kg and a power density of 198.54 W/kg at 0.2 A/g current density than the PIn/PVMo11 electrode. Both electrodes show a pseudocapacitance behavior due to the doping of redox-active polyoxomolybdates on the PIn surface and enhance the electrochemical properties. The electrodes' capacitive nature was measured by electrochemical impedance spectroscopy (EIS), which shows that the PIn/PVMo11 electrode has a resistive nature within the electrode-electrode interface. Moreover, the PIn/PV2Mo10 electrode offers remarkable cycle stability, retaining ∼84% of its capacitance after 10,000 cycles (∼83% for the PIn/PVMo11 electrode). The higher specific capacitance, faster charge/discharge rates, and higher cycle stability make them promising electrodes in supercapacitors

    Wheel-Shaped Polyoxotungstate [Cu 20

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    The Growth Curve Method to Rapidly Derive the Antibacterial Potential of Polyoxovanadates

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    In previous studies (Marques-da-Silva et al., 2019), we measured the minimum inhibitory concentrations (MICs) of three polyoxovanadates, namely V10, MnV11, and MnV13, against Escherichia coli. MICs were obtained following the standard method, which requires a 16–20 h culture and might neglect the effects of the compounds’ metabolism during incubation. In this work, we studied the action of those compounds against Enterococcus faecalis by monitoring the bacterial growth kinetics, and we observed that the inhibition was evident from the beginning of the exponential phase. Notably, data collected from just a 7 h culture was enough to identify the compounds with stronger antibacterial activity according to standard MICs

    Asymmetric polyoxometalate-polypyrrole composite electrode material for electrochemical energy storage supercapacitors

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    Nowadays, metal-oxides impregnated conducting polymers as electrode materials are attracted much attention due to their higher stability. Here, the metal-oxide cluster, polyoxometalate (K5H2[PV4W8O40]·11H2O, PV4W8), was introduced into the polypyrrole (PPy) matrix to overcome the polymers stability issues, and thus, the resulting novel PV4W8/PPy (symmetric) composite electrode has been reported. XPS confirmed the presence of all atoms on the polymer backbone with respective oxidation states. Nevertheless, doping of PV4W8 on the conductive PPy matrix's surface can affectively improve the ion's transfer. Finally, the asymmetric PV4W8-PPy/PPy composite exhibits a prodigious specific capacitance of 291 F g−1, larger than the PPy (90.01 F g−1) and PV4W8 (39.03 F g−1) at 0.4 A g−1 current density. The PV4W8-PPy/PPy (asymmetric) electrode showed excellent cycle stability. However, a symmetric supercapacitor device based on PV4W8/PPy composite possesses a specific capacitance of 195.27 F g−1 and an energy density of 8.94 Wh kg−1 at the same current density as PV4W8-PPy/PPy (asymmetric) electrode with remarkable cycle stability. © 2021 Elsevier B.V
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