The Experts below are selected from a list of 7452 Experts worldwide ranked by ideXlab platform
Jacques Nicolas - One of the best experts on this subject based on the ideXlab platform.
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effect of glutathione and maillard reaction Products prepared from glucose or fructose with glutathione on polyphenoloxidase from apple i enzymatic browning and enzyme activity inhibition
Food Chemistry, 2004Co-Authors: Catherine Billaud, Sophie Brunmerimee, Loic Louarme, Jacques NicolasAbstract:Abstract The effect of unheated and heated glutathione (GSH) and Maillard reaction Products (MRPs), derived from equimolar mixtures (0.25 M) glucose or fructose with GSH, on purified apple polyphenoloxidase (PPO) activity was investigated by polarography and spectrophotometry, using 4-methylcatechol as the main phenolic substrate. When assayed alone, glutathione interacted with enzyme-generated o -quinones, giving rise to colourless conjugates, as demonstrated by high pressure liquid chromatography (HPLC). By polarography, increasing concentrations (0–300 mM) of GSH, resulted in a high inhibitory effect on PPO activity, mostly due to a drop of pH of the reaction solutions to acidic values. Upon heating GSH at 90 °C, Thermal Degradation Product formation was responsible for a partial PPO inhibition. GSH-derived MRPs highly inhibited PPO activity, inhibition efficiency increasing with heating time (2–39 h) and temperature (80–110 °C). Compared with MRPs prepared from hexose with cysteine, those from GSH exhibited a more potent inhibitory effect, due to the presence of an additional carboxylic function on the tripeptide. Therefore, these MRPs could be considered as potential natural inhibitors for use with minimally processed fruits.
Massao Ionashiro - One of the best experts on this subject based on the ideXlab platform.
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lornoxicam drug a new study of Thermal Degradation under oxidative and pyrolysis conditions using the thermoanalytical techniques drx and lc ms ms
Thermochimica Acta, 2019Co-Authors: Ana Carina Sobral Carvalho, Georgia Alvim Coelho Zangaro, Richard Perosa Fernandes, Bruno Ekawa, A L C S Nascimento, B F Silva, Gage P Ashton, Gareth M B Parkes, Massao IonashiroAbstract:Abstract In the present work, the Thermal behavior of Lornoxicam drug was studied under oxidizing (air) and pyrolysis (N2) atmospheres using simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), differential scanning calorimetry (DSC), Hot Stage Microscopy (HSM) and Evolved Gas Analysis (EGA) in the form of thermogravimetry coupled to infrared spectroscopy (TG-FTIR) and mass spectrometry (TG-MS). The Thermal Degradation Product formed at different temperatures were examined using liquid chromatography coupled to mass spectrometry (LC–MS) and Powder X-Ray Diffraction (PXRD). The Thermal study showed that the drug does not melt, partially amorphized on heating, it is Thermally stable to 205 °C and undergoes Thermal decomposition in two overlapping mass loss steps. Furthermore, the DSC and MS techniques suggest that Thermal Degradation processes are very complex, which occur with the release of gaseous Products HCN, SO2, COS, CO2, N2O and CO and formation of three intermediate in the Thermal residue.
A L C S Nascimento - One of the best experts on this subject based on the ideXlab platform.
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lornoxicam drug a new study of Thermal Degradation under oxidative and pyrolysis conditions using the thermoanalytical techniques drx and lc ms ms
Thermochimica Acta, 2019Co-Authors: Ana Carina Sobral Carvalho, Georgia Alvim Coelho Zangaro, Richard Perosa Fernandes, Bruno Ekawa, A L C S Nascimento, B F Silva, Gage P Ashton, Gareth M B Parkes, Massao IonashiroAbstract:Abstract In the present work, the Thermal behavior of Lornoxicam drug was studied under oxidizing (air) and pyrolysis (N2) atmospheres using simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), differential scanning calorimetry (DSC), Hot Stage Microscopy (HSM) and Evolved Gas Analysis (EGA) in the form of thermogravimetry coupled to infrared spectroscopy (TG-FTIR) and mass spectrometry (TG-MS). The Thermal Degradation Product formed at different temperatures were examined using liquid chromatography coupled to mass spectrometry (LC–MS) and Powder X-Ray Diffraction (PXRD). The Thermal study showed that the drug does not melt, partially amorphized on heating, it is Thermally stable to 205 °C and undergoes Thermal decomposition in two overlapping mass loss steps. Furthermore, the DSC and MS techniques suggest that Thermal Degradation processes are very complex, which occur with the release of gaseous Products HCN, SO2, COS, CO2, N2O and CO and formation of three intermediate in the Thermal residue.
B Mortaigne - One of the best experts on this subject based on the ideXlab platform.
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analysis by pyrolysis gas chromatography mass spectrometry of glass fibre vinylester Thermal Degradation Products
Polymer Degradation and Stability, 1995Co-Authors: N Regnier, B MortaigneAbstract:Abstract The study of the Thermal Degradation of vinylester materials crosslinked with styrene by thermogravimetric analysis (TGA) and the identification of emission Products by pyrolysis/chromatography/mass spectrometry (PY/GC/MS) demonstrates that Thermal Degradation begins with a polystyrene chain depolymerization. It continues with the breaking of vinylester prepolymer chains at higher temperatures Thermal Degradation Product analysis allowed us to confirm polystyrene formation during resin crosslinking. A post-cured material allowed us to obtain better Thermal stability and to limit, for a given temperature, the fraction of volatile Products. The use of a 45 instead of a 50% styrene resin allowed us to limit the Degradation Product yield. The presence of glass fiber in the vinylester matrix decreases the number of crosslinking points and the Thermal Degradation occurs more readily in the prepolymer chain end.
Catherine Billaud - One of the best experts on this subject based on the ideXlab platform.
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effect of glutathione and maillard reaction Products prepared from glucose or fructose with glutathione on polyphenoloxidase from apple i enzymatic browning and enzyme activity inhibition
Food Chemistry, 2004Co-Authors: Catherine Billaud, Sophie Brunmerimee, Loic Louarme, Jacques NicolasAbstract:Abstract The effect of unheated and heated glutathione (GSH) and Maillard reaction Products (MRPs), derived from equimolar mixtures (0.25 M) glucose or fructose with GSH, on purified apple polyphenoloxidase (PPO) activity was investigated by polarography and spectrophotometry, using 4-methylcatechol as the main phenolic substrate. When assayed alone, glutathione interacted with enzyme-generated o -quinones, giving rise to colourless conjugates, as demonstrated by high pressure liquid chromatography (HPLC). By polarography, increasing concentrations (0–300 mM) of GSH, resulted in a high inhibitory effect on PPO activity, mostly due to a drop of pH of the reaction solutions to acidic values. Upon heating GSH at 90 °C, Thermal Degradation Product formation was responsible for a partial PPO inhibition. GSH-derived MRPs highly inhibited PPO activity, inhibition efficiency increasing with heating time (2–39 h) and temperature (80–110 °C). Compared with MRPs prepared from hexose with cysteine, those from GSH exhibited a more potent inhibitory effect, due to the presence of an additional carboxylic function on the tripeptide. Therefore, these MRPs could be considered as potential natural inhibitors for use with minimally processed fruits.