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    Wyświetlanie 1-6 z 6
    Tytuł:
    Thermal Decarboxylation of Betacyanins in Red Beet Betalain-Rich Extract
    Autorzy:
    Kumorkiewicz, Agnieszka
    Sutor, Katarzyna
    Nemzer, Boris
    Pietrzkowski, Zbigniew
    Wybraniec, Sławomir
    Powiązania:
    https://bibliotekanauki.pl/articles/1369582.pdf
    Data publikacji:
    2020
    Wydawca:
    Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
    Tematy:
    decarboxylation
    red beet root
    colorants
    betanin
    betalain-rich extract
    decarboxy-betacyanins
    Opis:
    Betalains are one of the most common groups of plant pigments found in nature, especially in red beetroot (Beta vulgaris L.) which is the main commercially exploited source of betalains produced in the form of concentrates or powders. This report presents results of thermal decarboxylation studies on betacyanins present in a specifically purified highly concentrated betalain-rich extract (BRE). The first tentative structures formed by decarboxylation of the main pigment present in BRE, betanin and its diastereomer, were established by means of liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS). In the extract, two new isomeric bidecarboxylated betanins were tentatively identified. A high rate of generation of 2-decarboxy-betanin/-isobetanin which are present in the BRE extract at very low level was observed, which was dependent on the starting concentration of the BRE substrate. The bidecarboxylated derivatives were generated at a higher rate mostly from 17-decarboxy-betanin/-isobetanin as well as 15-decarboxy-betanin by further decarboxylation at carbon C-2. Further studies will be performed to demonstrate if the decarboxylated betanins being products of heating B. vulgaris preparations can be used for various food applications with new health-promoting actions and colorant properties.
    Źródło:
    Polish Journal of Food and Nutrition Sciences; 2020, 70, 1; 7-14
    1230-0322
    2083-6007
    Pojawia się w:
    Polish Journal of Food and Nutrition Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Research on stability of gomphrenin pigments influenced by Cu2+ ions
    Autorzy:
    Szmyr, N.
    Wybraniec, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/115831.pdf
    Data publikacji:
    2017
    Wydawca:
    Fundacja na Rzecz Młodych Naukowców
    Tematy:
    Gomphrena globosa
    Betalains
    Betacyanins
    Gomphrenin
    LC-DAD-ESI-MS
    dehydrogenation
    decarboxylation
    Gomfrena kulista
    betalainy
    betacyjaniny
    gomphereniny
    odwodnienie
    dekarboksylacja
    Opis:
    This paper concerns the results of dehydrogenation of gomphrenin pigments isolated from the purple flowers of Gomphrena globosa L. depending on pH and Cu2+ activity. Betalains are the plant dyes divided into red-violet betacyanins and yellow-orange betaxanthins. These compounds show prohealth properties proven by numerous studies [1]. Isolation of gomphrenins from the plant material was performed in the following stages: preparative extraction, filtration on a silica layer, preliminary purification and concentration on a bed of strong anion exchanger, preparative chromatographic fractionation and sample liofilization. The dehydrogenation studies of gomphrenin I and II were carried out in aqueous solutions (pH 3, 5 and 7) catalyzed by Cu2+ ions addition. The resulting product mixtures of dehydrogenated and decarboxylated gomphrenin derivatives were monitored by high-performance liquid chromatography with diode-array and mass spectrometric detection (LC-DAD-ESI-MS). Based on the results, it can be stated that decarboxylated and dehydrogenated gomphrenin II derivatives are more stable than gomphrenin I derivatives, presumably due to acylation of the glucose moiety. The highest levels of gomphrenin I derivatives were observed at pH 7, however, they were mainly monodecarboxylated ones. At pH 3, significant fraction was represented by tridecarboxylated and dehydrogenated derivatives. The lowest yield of the degradation products was indicated at pH 5.
    Źródło:
    Challenges of Modern Technology; 2017, 8, 1; 13-18
    2082-2863
    2353-4419
    Pojawia się w:
    Challenges of Modern Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Research on dehydrogenation of gomphrenin in heated ammonia solutions of organic solvents
    Autorzy:
    Szmyr, N.
    Wybraniec, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/115847.pdf
    Data publikacji:
    2017
    Wydawca:
    Fundacja na Rzecz Młodych Naukowców
    Tematy:
    Gomphrena globosa
    Betalains
    Betacyanins
    Gomphrenin
    LC-DAD-ESI-MS
    dehydrogenation
    decarboxylation
    Gomfrena kulista
    betalainy
    betacyjaniny
    gomphereniny
    odwodnienie
    dekarboksylacja
    Opis:
    In this report, the influence of ammonia on dehydrogenation of gomphrenin pigment, isolated from purple inflorescences of Gomphrena globosa L., in selected organic solvents (methanol, ethanol, acetone and acetonitrile) at 40°C is presented. Betacyanins are water-soluble, vacuolar plant pigments. Due to their numerous pro-health properties, they can be applied in the pharmaceutical industry and as food colorants. However, as most of natural products, they are less stable than synthetic dyes, therefore, further studies need to be carried out on their stability, but also on determination of their degradation products as well as degradation mechanisms. For the experiments of the ammonia treatment, prolonged isolation of gomphrenin from the plant material including extraction, preliminary purification, preparative HPLC fractionation, concentration and liofilization were performed. The tested pigment dissolved in organic solvents was treated by ammonia and the samples for analysis were taken during and after reaction. For identification of obtained derivatives of gomphrenin, high-performance liquid chromatography with diode-array and mass spectrometric detection (LC-DAD-ESI-MS) was performed. As a result of heat processing, the mixture of decarboxylated and dehydrogenated gomphrenin derivatives was detected. Based on the experimental results, it can be stated that gomphrenin is characterized by the greatest stability in methanolic solutions while it is the most labile in the acetonitrilic ones.
    Źródło:
    Challenges of Modern Technology; 2017, 8, 1; 8-12
    2082-2863
    2353-4419
    Pojawia się w:
    Challenges of Modern Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Multiple isotope effects as a probe of the tartrate dehydrogenase-catalyzed oxidative decarboxylation of D-malate
    Autorzy:
    Karsten, W.
    Cook, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/147116.pdf
    Data publikacji:
    2002
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    isotope effects
    malic enzyme
    oxidative decarboxylation
    tartrate dehydrogenase
    Opis:
    A change in the dinucleotide reactant from NAD+ to the more oxidizing APAD+ in the malic enzyme reaction results in a change in the mechanism of oxidative decarboxylation of malate from stepwise to concerted [7]. In order to determine whether this is a phenomenon general to metal ion dependent â-hydroxyacid oxidative decarboxylases, tartrate dehydrogenase, which catalyzes a reaction diastereotopic to malic enzyme, was studied using the technique of multiple isotope effects. A primary deuterium isotope effect of 1.41 on V/Kmalate was measured, as well as a primary 13C-isotope effect of 1.0096. A decrease in the measured value of the 13C-isotope effect to 1.0078 is consistent with a stepwise mechanism, as observed for malic enzyme. The 13C-isotope effect with thioNAD+ also decreases from a value of 1.0053 using D-malate to 1.0009 using D-malate-2-D, consistent with stepwise oxidative decarboxylation with this alternative dinucleotide substrate. The data suggest that the change
    Źródło:
    Nukleonika; 2002, 47,suppl.1; 13-15
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of EDTA on stabilization of decarboxylated betalains
    Autorzy:
    Skopińska, A.
    Starzak, K.
    Wybraniec, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/115483.pdf
    Data publikacji:
    2012
    Wydawca:
    Fundacja na Rzecz Młodych Naukowców
    Tematy:
    betacyanins
    decarboxylation
    Beta vulgaris L.
    EDTA
    Opis:
    Betalains are known to be very sensitive to several factors, including higher temperature, therefore, the studies on their stability are essential for the food industry. In order to determine the stability of betanin derivatives during thermal treatment, a set of degradation experiments was performed, including the protective infl uence of EDTA as a chelating agent. The pigments were dissolved in aqueous solutions of acetonitrile, methanol and ethanol. The studies on thermal degradation of the pigments confi rmed their high lability in all investigated solvents. Under the infl uence of protective activity of EDTA, the rate of the degradation of the decarboxylated betalains was substantially decreased. The analysis of obtained absorption spectra of the degradation products indicated that under the infl uence of EDTA, the products retained the basic chromophoric skeleton.
    Źródło:
    Challenges of Modern Technology; 2012, 3, 4; 29-33
    2082-2863
    2353-4419
    Pojawia się w:
    Challenges of Modern Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Carbon-13 isotope effect for decarboxylation of phenylpropiolic acid (PPA) in concentrated phosphoric acids
    Autorzy:
    Zieliński, M.
    Zielińska, A.
    Papiernik-Zielińska, H.
    Ogrinc, N.
    Kobal, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/146141.pdf
    Data publikacji:
    2000
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    carbon-13
    concentrated phosphoric acids
    decarboxylation isotope effects
    decarboxylation mechanism
    phenylpropiolic acid
    Opis:
    13C isotope effects on the decarboxylation of phenylpropiolic acid (PPA) in 93–97% H3PO4 and in 23% diphosphoric acid in orthophosphoric acid have been investigated from 293 to 353 K. The initial 13C fractionations in all three systems are in agreement with the 13C decarboxylation fractionations expected assuming the loss of the one carbon-carbon bond in the transition state. In 100% H3PO4 and in 23% diphosphoric acid in orthophosphoric acid later fractions of carbon dioxide are depleted in carbon-13 to a greater degree than expected, probably due to isotopic preequilibria between stable and decarboxylating forms of PPA. At 353 K and higher temperature strong deviations of the experimental rate constants and of the experimental 13C fractionations from the values extrapolated from lower temperature are observed. A tentative decarboxylation scheme operating in concentrated phosphoric acid media is proposed.
    Źródło:
    Nukleonika; 2000, 45, 2; 121-124
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-6 z 6

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