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
This study presents the volatile constituents from leaves of Trifolium alexandrinum from Pakistan.The dried leaves were subjected to hydrodistillation for extraction and extracted volatile oil was subsequently charact...This study presents the volatile constituents from leaves of Trifolium alexandrinum from Pakistan.The dried leaves were subjected to hydrodistillation for extraction and extracted volatile oil was subsequently characterized by gas chromatography-mass spectrometry technique.A total of 22 compounds were identified where the most dominant constituents were:phytol(46.00%),palmitic acid(9.26%),phytol acetate(6.44%),and linolenic acid(3.47%).Most of these are well-known constituents to exhibit antibacterial,antioxidant,antitumor,and anti-inflammatory activities.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This study presents the volatile constituents from leaves of Trifolium alexandrinum from Pakistan.The dried leaves were subjected to hydrodistillation for extraction and extracted volatile oil was subsequently characterized by gas chromatography-mass spectrometry technique.A total of 22 compounds were identified where the most dominant constituents were:phytol(46.00%),palmitic acid(9.26%),phytol acetate(6.44%),and linolenic acid(3.47%).Most of these are well-known constituents to exhibit antibacterial,antioxidant,antitumor,and anti-inflammatory activities.
