Characterisation of peroxidation products arising from culinary oils exposed to continuous and discontinuous thermal degradation processes (original) (raw)
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FEBS Letters, 1994
The oxidative deterioration of glycerol‐bound polyunsaturated fatty acids (PUFAs) in culinary oils and fats during episodes of heating associated with normal usage (30–90 min at 180°C) has been monitored by high field 1H NMR spectroscopy. Thermal stressing of PUFA‐rich culinary oils generated high levels of n‐alkanals, trans‐2‐alkenals, alka‐2,4‐dienals and 4‐hydroxy‐trans‐2‐alkenals via decomposition of their conjugated hydroperoxydiene precursors, whereas only low concentrations of selected aldehydes were produced in oils with a low PUFA content, lard and dripping when subjected to the above heating episodes. Samples of repeatedly used, PUFA‐rich culinary oils obtained from restaurants also contained high levels of each class of aldehyde. The dietary, physiological and toxicological ramifications of the results obtained are discussed.
1 H NMR and EPR spectroscopies were employed to detect the evolution of lipid peroxidation products resulting from thermal stress in a vegetable oil. The obtained concentration profiles indicate that the secondary oxidation products (saturated and unsaturated aldehydes) may form not only via a direct degradation of primary oxidation products (hydroperoxides), as assumed in the classic kinetic models. In order to explain the observed concentration profiles, an alternate kinetic model is proposed where the aldehydes are additionally generated from hydroperoxides through an independent pathway.
2019
Objectives/Hypotheses: The adverse health effect potential of dietary lipid oxidation products (LOPs) has evoked much clinical interest. Therefore, we employed a <sup>1</sup>H NMR-linked Principal Component Regression (PCR) chemometrics modelling strategy to explore relationships between data matrices comprising (1) aldehydic LOP concentrations generated in culinary oils/fats when exposed to laboratory-simulated shallow frying practices, and (2) the prior saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acid (PUFA) contents of such frying media (FM), together with their heating time-points at a standard frying temperature (180 <sup>o</sup>C). Methods: Corn, sunflower, extra virgin olive, rapeseed, linseed, canola, coconut and MUFA-rich algae frying oils, together with butter and lard, were heated according to laboratory-simulated shallow-frying episodes at 180 <sup>o</sup>C, and FM samples were collected at time-points of 0, 5, 10...
Reliability of 1H NMR Analysis for Assessment of Lipid Oxidation at Frying Temperatures
Journal of the American Oil Chemists' Society, 2017
The reliability of a method using 1H NMR analysis for assessment of oil oxidation at frying temperatures was examined. During heating and frying at 180 °C, changes of soybean oil signals in the 1H NMR spectrum including olefinic (5.16–5.30 ppm), bisallylic (2.70–2.88 ppm), and allylic (1.94–2.15 ppm) proton signals relative to glyceride backbone CH2 (5.30–5.46 ppm) and aliphatic CH2 (1.05–1.71 ppm) signals showed strong correlations with conventional analytical methods including total polar compounds, polymerized triacylglycerols, and changes of linoleic acid and linolenic acid peaks in gas chromatography. For oils rich in oleic acid, mid‐oleic sunflower oil (NuSun) and high oleic soybean oil, only the olefinic and allylic proton signals are recommended for analysis due to the relatively low intensity of the bisallylic proton signal. Under these heating and frying conditions, signals indicating intermediate oxidation products, hydroperoxides, were not detected while very small signa...
Comprehensive Reviews in Food Science and Food Safety, 2014
This review summarizes present-day knowledge provided by proton nuclear magnetic resonance (1 H NMR) concerning food lipid thermo-oxidative degradation. The food lipids considered include edible oils and fats of animal and vegetable origin. The thermo-oxidation processes of food lipids of very different composition, occurring at low, intermediate, or high temperatures, with different food lipid surfaces exposed to oxygen, are reviewed. Mention is made of the influence of both food lipid nature and degradative conditions on the thermo-oxidation process. Interest is focused not only on the evolution of the compounds that degrade, but also on the intermediate or primary oxidation compounds formed, as well as on the secondary ones, from both qualitative and quantitative points of view. Very valuable qualitative and quantitative information is provided by 1 H NMR, which can be useful for metabolomic and lipidomic studies. The chemical shift assignments of spectral signals of protons of primary (hydroperoxides and hydroxides associated with conjugated dienes) and secondary, or further (aldehydes, epoxides, among which 9,10-epoxy-12-octadecenoate [leukotoxin] can be cited, alcohols, ketones) oxidation compounds is summarized. It is worth noting the ability of 1 H NMR to detect toxic oxygenated α,β-unsaturated aldehydes, like 4-hydroperoxy-, 4,5-epoxy-, and 4-hydroxy-2-alkenals, which can be generated in the degradation of food lipids having omega-3 and omega-6 polyunsaturated groups in both biological systems and foodstuffs. They are considered as genotoxic and cytotoxic, and are potential causative agents of cancer, atherosclerosis, and Parkinson's and Alzheimer's diseases.
Rivista Italiana Delle Sostanze Grasse
High-resolution proton nuclear magnetic resonance (1H-NMR) spectroscopy (400-600 MHz) was applied to the quantitative analysis of hydroperoxide decomposition products in thermally oxidized oils. Different oils (olive, sunflower and soybean) were heated in a thermostatic bath (180°C for 360 min). Proton NMR quantitative aldehyde analysis (n-alkanals, trans-2-alkenals, 4-hydroxy-trans-2-alkenals, alka-2,4-dienals) of fifteen oil samples (0, 60, 120, 240 and 360 minute heating) was compared with that of total polar compounds through silica column chromatography and of short-chain fatty acids. A good linear relationship (R2=0.94) was found between the unsaturated aldehyde level and the amount of methyl-octanoate as well as between total aldehyde determined by 1H-NMR and total polar compounds (R2=0.92). The same NMR sensitivity obtained at 400 MHz through 3000 scans was reached with only 64 scans for a total acquisition time of 2 min at 600 MHz. The potential use of 1H-NMR as a direct to...
Chemometric assessment of thermal oxidation of some edible oils
Journal of Thermal Analysis and Calorimetry, 2010
The effect of microwave heating was studied in six varieties of edible oil. Variations in physicochemical properties were observed and compared with the data obtained by hot plate heating. Fourier-transform infrared spectra of the oils showed substantial variations after both types of heating in the region of hydrogen's stretching (C-H) vibration, region of double bond's stretching (C=O), and fingerprint region. The visible spectra of mustard and olive oil showed the reduction in carotenoid, flavonoid, and chlorophyll pigments after heating. The oil samples were discriminated as saturated, monounsaturated, and polyunsaturated fats using chemometric techniques on physical and spectroscopic measurements.
Effect of Different Cooking Vessels on Heat Induced Lipid Peroxidation of Different Edible Oils
Journal of Food Biochemistry, 2008
Sunflower, coconut, palm and sesame oils were evaluated for heat induced peroxidation as assessed from malondialdehyde (MDA) generation when heated in iron, copper, stainless steel, aluminium and glass vessels on a controlled flame for 0, 5, 10 and 20 min. The MDA generation on heating was time dependent in all the oils. The extent of heat-induced change was the least in coconut oil followed by sesame oil. The heat induced MDA generation was the maximum in sunflower oil. The change was very less in aluminium and glass vessel but was very high in iron and copper vessels. The results show that aside from the level of anti-oxidants and unsaturation of oils, the transitional element used in cooking vessels also determine the extent of heat-induced peroxidation of oils, the impact of which is discussed in light of the harmful effects of MDA on health.