Deep frying with repeated use of same edible oil leads to the formation of lipid oxidation products. The presence of these oxidized products formed during frying at elevated temperature is hazardous for human health a...Deep frying with repeated use of same edible oil leads to the formation of lipid oxidation products. The presence of these oxidized products formed during frying at elevated temperature is hazardous for human health and therefore, requires prompt analysis for ensuring its fitness/quality. In this study, oxidative degradation of thermally stressed edible oils canola, sunflower and palm olein shortening was studied at 180°C ± 5°C up to 48 hours. Palm olein shortening remained stable during this period as the increase in its acid value was significantly less than canola and sunflower seed oils. The shortening samples were further studied by attenuated total reflectance Fourier transformation infrared (ATR-FTIR) and gas chromatography mass spectrometry (GC-MS) to evaluate the formation of various oxidation products due to thermal stress. ATR-FTIR indicates the formation of free fatty acids (FFAs), aldehyde groups and change in degree of unsaturation while GC-MS gives important information about profile of FFAs. The combination of these analytical techniques is useful for rapid and highly sensitive analysis of oxidized edible oil thus, ensuring its quality and fitness for safe use.展开更多
Methanol and ethanol fuel cells are getting important day by day because of energy crises. Main concern for fuel cell is the efficiency of the metal catalyst used for oxidation of methanol and ethanol. In this work, s...Methanol and ethanol fuel cells are getting important day by day because of energy crises. Main concern for fuel cell is the efficiency of the metal catalyst used for oxidation of methanol and ethanol. In this work, surfactant reformed electrodes by introducing sodium dodecyl sulphate (SDS), surfactant, at the surface of graphite electrodes along the metal nanoparticles were tried to develop. Idea behind it is to enhance the catalytic activity of metal nanoparticles through SDS. Modification of the graphite electrodes by SDS was characterized using Fourier transform infrared (FTIR) spectroscopy. Afterwards through electrochemical deposition, iron nanoparticles were got deposited on SDS modified and unmodified graphite electrodes which acted as catalyst. SDS modified iron deposited electrodes were utilized for the oxidation of methanol and ethanol in basic media. It was expected that SDS deposited at the surface of the electrodes would play an effective role in enhancing the rate of the oxidation reaction just by creating interaction between catalyst and reactant. Similar oxidation reaction was studied using unmodified iron deposited graphite electrode. Comparison of the results of oxidation reactions encourages the use of surfactant to speed up the oxidation reaction.展开更多
文摘Deep frying with repeated use of same edible oil leads to the formation of lipid oxidation products. The presence of these oxidized products formed during frying at elevated temperature is hazardous for human health and therefore, requires prompt analysis for ensuring its fitness/quality. In this study, oxidative degradation of thermally stressed edible oils canola, sunflower and palm olein shortening was studied at 180°C ± 5°C up to 48 hours. Palm olein shortening remained stable during this period as the increase in its acid value was significantly less than canola and sunflower seed oils. The shortening samples were further studied by attenuated total reflectance Fourier transformation infrared (ATR-FTIR) and gas chromatography mass spectrometry (GC-MS) to evaluate the formation of various oxidation products due to thermal stress. ATR-FTIR indicates the formation of free fatty acids (FFAs), aldehyde groups and change in degree of unsaturation while GC-MS gives important information about profile of FFAs. The combination of these analytical techniques is useful for rapid and highly sensitive analysis of oxidized edible oil thus, ensuring its quality and fitness for safe use.
文摘Methanol and ethanol fuel cells are getting important day by day because of energy crises. Main concern for fuel cell is the efficiency of the metal catalyst used for oxidation of methanol and ethanol. In this work, surfactant reformed electrodes by introducing sodium dodecyl sulphate (SDS), surfactant, at the surface of graphite electrodes along the metal nanoparticles were tried to develop. Idea behind it is to enhance the catalytic activity of metal nanoparticles through SDS. Modification of the graphite electrodes by SDS was characterized using Fourier transform infrared (FTIR) spectroscopy. Afterwards through electrochemical deposition, iron nanoparticles were got deposited on SDS modified and unmodified graphite electrodes which acted as catalyst. SDS modified iron deposited electrodes were utilized for the oxidation of methanol and ethanol in basic media. It was expected that SDS deposited at the surface of the electrodes would play an effective role in enhancing the rate of the oxidation reaction just by creating interaction between catalyst and reactant. Similar oxidation reaction was studied using unmodified iron deposited graphite electrode. Comparison of the results of oxidation reactions encourages the use of surfactant to speed up the oxidation reaction.
