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1.
Hydrolysis of used frying palm olein and sunflower oil catalyzed by porcine pancreatic lipase 总被引:1,自引:0,他引:1
R. Arroyo F. J. Sánchez-Muniz C. Cuesta F. J. Burguillo J. M. Sánchez-Montero 《Lipids》1996,31(11):1133-1139
The enzymatic hydrolysis of frying used vegetable oils with different degrees of alteration were measured using porcine pancreatic
lipase (acylglycerol acylhydrolase EC 3.1.1.3). Successive frying of potatoes significantly increased the level of total polar
lipid content in the palm olein from 9.3±0.1 mg/100 mg oil to 26.4±0.3 mg/100 mg oil after 90 fryings, and from 4.0±0.1 mg/100
mg oil to 27.7±0.3 mg/100 mg oil in sunflower oil after 60 fryings. Triacylglycerol polymers, triacylglycerol dimers, and
oxidized triacylglycerols also increased 37-, 7.9-, and 7.5-times in palm olein, respectively, and 56-, 22-, and 4.7-times
in sunflower oil, respectively. However, diacylglycerols and free fatty acid levels related to hydrolytic alteration did not
increase with the number of fryings in both oils. The substrate concentration in the reactor was determined by calculating
the molecular weight of each oil showing a different degree of alteration. We compared the methodology used by us and that
used by other authors. The results show that the methods are reproducible and that the values obtained are in concordance
with theoretical values. The kinetic parameters apparent Michaelis-Menten constant (K
M
app
) and apparent maximum velocity of hydrolysis (V
max
app
) were different in unused palm olein (5.1±0.7 and 166±7.6, respectively) than in sunflower oil (2.2±0.3 and 62±2.2, respectively).
However, changes inK
M
app
andV
max
app
were not related to the degree of alteration of the oils. 相似文献
2.
Arkadiusz Szterk Marek Roszko Ewa Górnicka 《Journal of the American Oil Chemists' Society》2013,90(4):483-491
The aim of this study was to examine the oxidation of selected plant oils in concentrated beverage emulsions colored with natural β-carotene. Carotenoid preparations obtained from carrots were dissolved in cold-pressed linseed oil, refined canola oil, and refined palm olein. Oxidative stability of the lipids was examined with and without addition of the pigment to the oil/water (O/W) emulsion. Carotenoid/lipid hydro peroxide (LOOH) concentration was evaluated using two different methods: LOOH + Fe2+ reaction connected with a colored complex of ammonium thiocyanate determined with the help of a spectrophotometer, and LOOH determined with the help of a chemiluminometer. It was shown that oxidation rate of lipids in the O/W emulsions strongly depended on chemical composition of the lipid fraction (type of oil used). Presence of the carotenoid pigment increased the rate. Therefore, if a carotenoid-containing emulsion is to be stable, it should be based on oils of a high oxidative stability. 相似文献
3.
Xin-Qing Xu Viet Hung Tran Martin Palmer Keith White Philip Salisbury 《Journal of the American Oil Chemists' Society》1999,76(9):1091-1099
The performance of three high-oleic canola oils with different levels of linolenic acid [low-linolenic canola (LLC), medium-linolenic
canola (MLC), and high-linolenic canola (HLC)], a medium-high-oleic sunflower oil, a commercial palm olein and a commercial,
partially hydrogenated canola oil, was monitored by chemical and physical analyses and sensory evaluation during two 80-h
deep-frying trials with potato chips. Linolenic acid content was a critical factor in the deep-frying performance of the high-oleic
canola oils and was inversely related to both the sensory ranking of the food fried in the oils and the oxidative stability
of the oils (as measured by color index, free fatty acid content, and total polar compounds). LLC and sunflower oil were ranked
the best of the six oils in sensory evaluation, although LLC performed significantly better than sunflower oil in color index,
free fatty acid content, and total polar compounds. MLC was as good as palm olein in sensory evaluation, but was better than
palm olein in oxidative stability. Partially hydrogenated canola oil received the lowest scores in sensory evaluation. High-oleic
canola oil (Monola) with 2.5% linolenic acid was found to be very well suited for deep frying. 相似文献
4.
The Effect of Type of Oil and Degree of Degradation on Glycidyl Esters Content During the Frying of French Fries
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Magda Aniołowska Agnieszka Kita 《Journal of the American Oil Chemists' Society》2015,92(11-12):1621-1631
The aim of the study was to determine the effect of oil degradation on the content of glycidyl esters (GEs) in oils used for the frying of French fries. As frying media, refined oils such as rapeseed, palm, palm olein and blend were used. French fries were fried for 40 h in oils heated to 180 °C in 30‐min cycles. After every 8 h of frying, fresh oil and samples were analyzed for acid and anisidine values, color, refractive index, fatty acid composition, and content and composition of the polar fraction. GEs were determined by LC–MS. Hydrolysis and polymerization occurred most intensively in palm olein, while oxidation was reported for rapeseed oil. The degradation of oil caused increased changes in the RI of frying oils. Losses of mono‐ and polyunsaturated fatty acids were observed in all samples, with the largest share in blend. The highest content of GE found in fresh oil was in palm olein (25 mg kg?1) and the lowest content of GE was found in rapeseed oil (0.8 mg kg?1). The palm oil, palm olein and blend were dominated by GEs of palmitic and oleic acids, while rapeseed oil was dominated by GE of oleic acid. With increasing frying time, the content of GEs decreased with losses from 47 % in rapeseed oil to 78 % in palm oil after finishing frying. 相似文献
5.
Xin Guo Longkai Shi Joseph Heng Xiaotian Sun Li Liang Ruijie Liu Ming Chang Xingguo Wang 《European Journal of Lipid Science and Technology》2023,125(6):2200172
Lipid-based delivery systems are widely used to incorporate chemicals with poor solubility. The influence of tocopherol and sesamol on emulsion delivery systems, including their bioactivity, is not well-known. Herein, the overall aim of this study is to understand the effect of tocopherol and sesamol on the physical stability and bioactivity of various emulsions comprised of oil (medium chain triglyceride, coconut oil, palm oil) with different carbon chain lengths using the C. elegans model. All emulsions show good physical stability; droplet size, polydispersity index, zeta potential, and microstructure are relatively constant over the incubation time. Tocopherol and sesamol show the greatest bioactivity (greater lipid-lowering effect and in vivo antioxidant activity) in emulsions fabricated with palm oil. Knowledge on emulsion stability and bioactivity is important for delivery systems in the food industry involving tocopherol, sesamol, and other related bioactive compounds. 相似文献
6.
Yong Wang Mouming Zhao Shuze Tang Keke Song Xue Han Shiyi Ou 《Journal of the American Oil Chemists' Society》2010,87(5):483-491
The oxidative stability of diacylglycerol (DAG)-enriched soybean oil and palm olein produced by partial hydrolysis using phospholipase
A1 (Lecitase Ultra) and molecular distillation was investigated at 110 °C by the Rancimat method with and without addition
of synthetic antioxidants. Compared with triacylglycerol oils, the DAG-enriched oils displayed lower oxidative stability due
to a higher content of unsaturated fatty acids and a lower level of tocopherols. With the addition (50–200 mg/kg) of tert-butylhydroquinone (TBHQ) or ascorbyl palmitate (AP), the oxidative stability indicated by induction period (IP) of these
DAG-enriched oils under the Rancimat conditions was improved. The IP of the diacylglycerol-enriched soybean oil increased
from 4.21 ± 0.09 to 12.64 ± 0.42 h when 200 mg/kg of TBHQ was added, whereas the IP of the diacylglycerol-enriched palm olein
increased from 5.35 ± 0.21 to 16.24 ± 0.55 h when the same level of AP was added. Addition of TBHQ, alone and in combination
with AP resulted in a significant (p ≤ 0.05) increase in oxidative stability of diacylglycerol-enriched soybean oil. AP had a positive synergistic effect when
used with TBHQ. 相似文献
7.
A simple and reliable high-performance liquid chromatography method for the analysis of diesel oil in contaminated edible
oils is described. Analysis performed using a diol column with a mobile phase of heptane and isopropanol (94∶6, vol/vol).
Although baseline separation between diesel and other background fluorescent components was not achieved, quantitation was
still possible using baseline integration. The method is linear over the range of 5–1000 μg/g with a correlation coefficient
(r
2) of 0.9984. Average recoveries from spiked edible oils were 94.4–101.3%, with a limit of quantitation (LOQ) of 5 μg/g for
sunflower oil, palm olein, and groundnut oil. Corn oil has a higher content of ester components, thus, LOQ was slightly worse
(40 μg/g). The applicability of the method was confirmed by gas chromatography-mass spectroscopic detection to show the presence
of diesel hydrocarbons in the suspected contaminated crude palm oil. This procedure provides a simple and sensitive method
for determining diesel oil concentration in contaminated edible oils without prior sample cleanup or extraction. 相似文献
8.
An HPLC method for the determination of partially hydrogenated terphenyls-based thermal heating fluid, Therminol 66™, in various vegetable oils is described. Direct analysis of palm olein showed that the 3- and 4-cyclohexylbiphenyl peaks
of the Therminol 66™ used in quantitative analysis co-eluted with other fluorescent peaks present naturally in the oil. However, those interfering
peaks were readily removed after saponification of palm olein. The concentrations of the 3- and 4-cyclohexylbiphenyls of Therminol
66™ were monitored by fluorescence detection at 257 (excitation) and 320 nm (emission). The calibration graph obtained by using
the peak areas of the 3- and 4-cyclohexylbiphenyls against the concentrations of Therminol 66™ was linear, with a correlation coefficient of 0.994. The limit of quantitation, using spiked palm olein, was as low as 0.2
μg/g. The coefficients of variation obtained from the intra- and interday studies obtained by using three spiked concentrations
(0.2, 0.5, and 1.0 μg/g) were 1.76–6.43 and 3.77–10.4%, respectively. The mean recovery value obtained from sunflower, soybean,
and canola oils was more than 88.7%. 相似文献
9.
S. C. Yap Y. M. Choo N. F. Hew S. F. Yap H. T. Khor A. S. H. Ong S. H. Goh 《Lipids》1995,30(12):1145-1150
The oxidative susceptibilities of low density lipoproteins (LDL) isolated from rabbits fed high-fat atherogenic diets containing
coconut, palm, or soybean oils were investigated. New Zealand white rabbits were fed atherogenic semisynthetic diets containing
0.5% cholesterol and either (i) 13% coconut oil and 2% corn oil (CNO), (ii) 15% refined, bleached, and deodorized palm olein
(RBDPO), (iii) 15% crude palm olein (CPO), (iv) 15% soybean oil (SO), or (v) 15% refined, bleached, and deodorized palm olein
without cholesterol supplementation [RBDPO(wc)], for a period of twelve weeks. Total fatty acid compositions of the plasma
and LDL were found to be modulated (but not too drastically) by the nature of the dietary fats. Cholesterol supplementation
significantly increased the plasma level of vitamin E and effectively altered the plasma composition of long-chain fatty acids
in favor of increasing oleic acid. Oxidative susceptibilities of LDL samples were determined by Cu2+-catalyzed oxidation which provide the lag times and lag-phase slopes. The plasma LDL from all palm oil diets [RBDPO, CPO,
and RBDPO(wc)] were shown to be equally resistant to the oxidation, and the LDL from SO-fed rabbits were most susceptible,
followed by the LDL from the CNO-fed rabbits. These results reflect a relationship between the oxidative susceptibility of
LDL due to a combination of the levels of polyun-saturated fatty acids and vitamin E.
Based on a paper presented at the PORIM International Palm Oil Congress (PIPOC) held in Kuala Lumpur, Malaysia, 1993. 相似文献
10.
Luz Bertoia Jorge R. Wagner Andrés L. Márquez 《Journal of the American Oil Chemists' Society》2020,97(10):1071-1081
The objective was to study the microstructure and freeze–thaw stability of margarine-like emulsions formulated with vegetable fats using differential scanning calorimetry. Emulsions were prepared with 20% w/w dispersed aqueous phase and a continuous lipid phase composed by coconut oil (CO) and/or palm oil (PO) plus polyglycerol polyricinoleate (PGPR) as emulsifier. Mean temperature (TM) and crystallization enthalpy (ΔHc) were obtained from the exothermic peaks corresponding to freezing of aqueous phase. Successive cooling–heating–cooling cycles were applied to analyze changes in the exothermic peak. The emulsion prepared with CO (without PO) and 1% w/w PGPR in lipid phase showed higher water droplets size (TM = −44.8 ± 0.1 °C) and lower quantity of stabilized aqueous phase (ΔHc = 28.9 ± 1.2 J g−1) prior to application of temperature cycles, while coalescence and (presumably) water transfer processes occurred during the treatment. The use of 2% w/w PGPR was sufficient to accomplish full stabilization of aqueous phase (TM = −45.9 ± 0.1 °C; ΔHc = 42.6 ± 0.3 J g−1) before and after the freeze–thaw treatment. The total or partial (50%) substitution of CO by PO in emulsions with 1% w/w PGPR also improved the stability of the system, exhibiting slight microstructural changes. This enhanced stability would be linked to reduced water droplets size because of more rapid crystallization of lipid phase and immobilization of aqueous phase after emulsion preparation. In conclusion, it is possible to obtain margarine-like emulsions prepared with CO and/or PO using relatively low emulsifier concentration and maintaining a desired microstructure after freeze-thawing if the percentage ratio of both fats is controlled. 相似文献
11.
Soek Sin Teh Harrison Lik Nang Lau 《Journal of the American Oil Chemists' Society》2023,100(8):651-661
Edible oils contain naturally occurring phytonutrients and therefore exhibit numerous beneficial health effects. However, the phytonutrients tend to degrade in different extent with storage duration and temperature. In this study, the impact of storage conditions on the stability of phytonutrients, including vitamin E, carotenoid, phytosterols and squalene, and oil quality, including free fatty acids (FFA), peroxide value (PV), anisidine value (AV), and oxidative stability index (OSI) of red palm-pressed mesocarp olein, palm olein, extra virgin olive oil, and sunflower oil were investigated. The oils were stored in three conditions, 23°C (with light and without light) and 35°C (without light). Results showed that the retention percentages of phytonutrients where in the range of 0%–100% for vitamin E, 51.24%–83.63% for carotenoid, 83.40%–100% for phytosterols and 27.94%–100% for squalene. Pearson correlation analysis between phytonutrients and oil quality of oils in different storage conditions showed that correlation coefficient values (r) were in the range of −1 to 0 for FFA, −1 to 0.22 for PV, −1 to 0.33 for AV, and −0.23 to 1 for OSI, implying that correlations between both variables are not in same direction. Degradation studies of phytonutrients using zero-order kinetic model where optimum-case conditions exhibited highest half-life (t1/2) among the three conditions. In conclusion, storage conditions and synergistic effect affected the phytonutrients stability in the oils and oil quality in different extent. In general, storage at ambient temperature and dark condition contributed to the best phytonutrients retention and oil quality. 相似文献
12.
Bertrand Matthäus Norbert U. Haase Günter Unbehend 《Journal of the American Oil Chemists' Society》2009,86(8):799-808
The effects of frying Berlin doughnuts and potato crisps in high-oleic, low-linolenic (HOLL) rapeseed oil were compared to
other commonly used oils (i.e., palm olein, high-oleic sunflower oil, or partially hydrogenated oils). The chemical parameters
characterizing the oxidative state of the products fried in HOLL were comparable to products being fried in other commonly
used oils. The sensory characteristics of potato crisps fried in HOLL rapeseed oil were satisfactory and comparable to products
fried in the other oils. Potato crisps were stable under nitrogen atmosphere for 20 weeks as measured by sensory quality scores.
However, a storage time of 16 weeks was achieved for products stored under normal atmosphere. The suitability of HOLL rapeseed
oil to improve the storage stability of Berlin doughnuts was limited. The sensory quality decreased during storage due to
the development of abnormal taste and smell. Changes in the sensory quality were comparable to the results of the partially
hydrogenated oils but worse for products fried in palm olein. Nevertheless, HOLL was a good alternative to partially hydrogenated
oils as a frying medium. 相似文献
13.
This study considered the stability and rheology of a type of high internal phase water-in-oil emulsions (W/O) emulsion. The aqueous phase of the emulsions is a super-cooled inorganic salt solution. The oil phase is a mixture of industrial grade oils and stabilizer. Instability of these systems manifests as crystallization of the metastable dispersed droplets with time. This work focused on the effects of oil polarity and oil viscosity on the stability of these emulsions. Ten types of industrial oils, covering the viscosity range 1.4–53.2?cP, and with varying polarity, were used in combination with polymeric poly(isobutylene) succinic anhydride (PIBSA) and sorbitan monooleate (SMO)-based surfactants. The effect of oil relative polarity on rheological parameters of the emulsion was evident mainly in the emulsions stabilized using polymeric surfactant, whereas the oil viscosity did not show any significant effect. The optimum stability of the emulsions stabilized with SMO was achieved using high polar oils with a viscosity of 3?±?0.5?cP. However, when using the PIBSA surfactant, the best emulsion stability was achieved with low polar, high viscosity oils. 相似文献
14.
W. Ammawath Y. B. Che Man R. B. Abdul Rahman B. S. Baharin 《Journal of the American Oil Chemists' Society》2006,83(3):187-191
A simple, rapid, and direct FTIR spectroscopic method was developed for the determination of BHT content in refined, bleached,
and deodorized (RBD) palm olein and RBD palm oil. The method used sodium chloride windows with a 50-mm transmission path.
Fifty stripped oil samples of both RBD palm olein and RBD palm oil were spiked with known amounts of BHT concentrations up
to 300 mg/kg (ppm). The data were separated into two sets for calibration and validation using partial least squares models.
FTIR results for both oils correlated well with results obtained by the IUPAC HPLC-based method. For RBD palm olein, the coefficient
of determination (R
2) was 0.9907 and the SE of calibration (SEC) was 8.47 ppm. For RBD palm oil, an R
2 of 0.9848 and an SEC of 10.73 ppm were achieved. Because of the significant decrease in analysis time and reduction in solvent
usage, this FTIR method for BHT is especially well suited for routine quality control applications in the palm oil industry. 相似文献
15.
The effects of droplet size and emulsifiers on oxidative stability of polyunsaturated TAG in oil-in-water (o/w) emulsions
with droplet sizes of 0.806±0.0690, 3.28±0.0660, or 10.7±0.106 μm (mean ± SD) were investigated. Hydroperoxide contents in
the emulsion with a mean droplet size of 0.831 μm were significantly lower than those in the emulsion with a mean droplet
size of 12.8 μm for up to 120 h of oxidation time. Residual oxygen contents in the headspace air of the vials containing an
o/w emulsion with a mean droplet size of 0.831 μm were lower compared with those of the emulsion with a mean droplet size
of 12.8 μm. Hexanal developed from soybean oil TAG o/w emulsions with smaller droplet size showed significantly lower residual
oxygen contents than those of the larger droplet size emulsions. Consequently, oxidative stability of TAG in o/w emulsions
could be controlled by the size of oil droplet even though the origins of TAG were different. Spin-spin relaxation time of
protons of acyl residues on TAG in o/w emulsions measured by 1H NMR suggested that motional frequency of some acyl residues was shorter in o/w emulsions with a smaller droplet size. The
effect of the wedge associated with hydrophobic acyl residues of emulsifiers was proposed as a possible mechanism to explain
differences in oxidative stability between o/w emulsions with different droplet sizes. 相似文献
16.
R. E. Timms 《European Journal of Lipid Science and Technology》1986,88(8):294-300
By the end of the century palm kernel (PK) oil is forecast to rank fifth in volume of world trade in oils, only slightly behind coconut oil. PK oil received by Malaysian refiners is of good quality, typically below 2% in free fatty acids, and is easily refined. PK oil is fractionated to give a higher melting fraction (stearin) and a lower melting fraction (olein). The various processes used are described. PK oil, olein or stearin are also hydrogenated to give a range of products ranging in melting point from about 24 to 44°C. PK oil and olein are interesterified alone or in blends with a non-lauric oil to give products with improved melting properties and utility. The utilisation of PK oil in the main application areas of confectionery fats, non-dairy/imitation dairy products, biscuit creams, industrial margarines, nut roasting and spray oils are discussed. 相似文献
17.
Use of the SAW Sensor Electronic Nose for Detecting the Adulteration of Virgin Coconut Oil with RBD Palm Kernel Olein 总被引:1,自引:0,他引:1
A. M. Marina Y. B. Che Man I. Amin 《Journal of the American Oil Chemists' Society》2010,87(3):263-270
An electronic nose (zNose™) was applied to the detection of adulteration of virgin coconut oil. The system, which is based
on a surface acoustic wave sensor was used to generate a pattern of volatile compounds present in the samples. Virgin coconut
oil was mixed with refined, bleached and deodorized palm kernel olein at a level of adulteration from 1 to 20% (wt/wt). Adulterant
peaks were identified from the chromatogram profile and fitted to a curve using linear regression. The best relationship (R
2 = 0.91) was obtained between the peak tentatively identified as methyl dodecanoate and the percentage of palm kernel olein
added. Pearson’s correlation coefficients (r) of 0.92 and 0.89 were obtained between adulterant peak methyl dodecanoate and of the iodine and peroxide values, respectively.
Principal component analysis (PCA) was used to differentiate between pure and adulterated samples. The PCA provided good differentiation
of samples with 74% of the variation accounted for by PC 1 and 17% accounted for by PC 2. Pure samples formed a separate cluster
from all of the adulterated samples. 相似文献
18.
Julie Boisramé-Helms Xavier Delabranche Andrey Klymchenko Jocelyne Drai Emilie Blond Fatiha Zobairi Yves Mely Michel Hasselmann Florence Toti Ferhat Meziani 《Lipids》2014,49(11):1091-1099
The aim of this study was to assess how lipid emulsions for parenteral nutrition affect lipopolysaccharide (LPS)‐induced acute monocyte inflammation in vitro. An 18 h long LPS induced human monocyte leukemia cell stimulation was performed and the cell‐growth medium was supplemented with three different industrial lipid emulsions: Intralipid®, containing long‐chain triglycerides (LCT—soybean oil); Medialipid®, containing LCT (soybean oil) and medium‐chain triglycerides (MCT—coconut oil); and SMOFlipid®, containing LCT, MCT, omega‐9 and ‐3 (soybean, coconut, olive and fish oils). Cell viability and apoptosis were assessed by Trypan blue exclusion and flow cytometry respectively. Monocyte composition and membrane remodeling were studied using gas chromatography and NR12S staining. Microparticles released in supernatant were measured by prothrombinase assay. After LPS challenge, both cellular necrosis and apoptosis were increased (threefold and twofold respectively) and microparticle release was enhanced (sevenfold) after supplementation with Medialipid® compared to Intralipid®, SMOFlipid® and monocytes in the standard medium. The monocytes differentially incorporated fatty acids after lipid emulsion challenge. Finally, lipid‐treated cells displayed microparticles characterized by disrupted membrane lipid order, reflecting lipid remodeling of the parental cell plasma membrane. Our data suggest that lipid emulsions differentially alter cell viability, monocyte composition and thereby microparticle release. While MCT have deleterious effects, we have shown that parenteral nutrition emulsion containing LCT or LCT and MCT associated to n‐3 and n‐9 fatty acids have no effect on endotoxin‐induced cell death and inflammation. 相似文献
19.
Pan-frying is a popular frying method at home and in many restaurants. Pan-frying stabilities of two frying oils with similar
iodine values (IV)—mid-oleic sunflower oil (NuSun oil; IV=103.9) and a commercial canola oil (IV=103.4)—were compared. Each
oil sample was heated as a thin film on a Teflon-coated frying pan at ∼180°C to a target end point of ≥20% polymer. High-performance
size-exclusion chromatography analysis of the mid-oleic sunflower and canola oil samples indicated that the heated samples
contained 20% polymer after approximately 18 and 22 min of heating, respectively. The food oil sensor values increased from
zero to 19.9 for the canola sample and from zero to 19.8 for the mid-oleic sunflower sample after 24 min of heating. The apparent
first-order degradation rate for the mid-oleic sunflower sample was 0.102±0.008 min−1, whereas the rate for the canola sample was 0.092±0.010 min−1. The acid value increased from approximately zero prior to heating to 1.3 for the canola sample and from zero to 1.0 for
the mid-oleic sunflower sample after 24 min of heating. In addition, sensory and volatile analyses of the fried hash browns
obtained from both oils indicated there were no significant differences between the two fried potato samples. 相似文献
20.
Elham Tabee Sodeif Azadmard-Damirchi Margaretha Jägerstad Paresh C. Dutta 《Journal of the American Oil Chemists' Society》2008,85(9):857-867
The first part of this study evaluated oxidative stability in high-oleic rapeseed oil, palm olein, refined olive oil, low
erucic acid rapeseed oil and sunflower oil. The results showed oxidative stability in the order: palm olein > high-oleic rapeseed
oil > refined olive oil > low erucic acid rapeseed oil > sunflower oil, as determined by the Rancimat method. Addition of
α-tocopherol at high levels of up to 0.2% increased the oxidative stability of refined olive oil, whereas the opposite effect
was generally observed in the other oil samples. In the second part of the study, high-oleic rapeseed oil, palm olein, refined
olive oil and refined olive oil containing 0.2% α-tocopherol were heated for 3, 6, 9 and 12 h at 180 °C. The peroxide and
p-anisidine values generally increased over time in the samples, including olive oil containing 0.2% α-tocopherol. High-oleic
rapeseed oil contained the highest amount of total sterols and total phytosterol oxidation products (POPs), but during heating
the total POPs content increased moderately (~10%), in contrast to the threefold increase after 12 h of heating in palm olein
and refined olive oil. Very high levels of 6-hydroxy derivatives of brassicastanol, campestanol and sitostanol and of 7-ketobrassicasterol
were observed in high-oleic rapeseed oil samples. Addition of 0.2% α-tocopherol during heating significantly decreased POPs
formation in refined olive oil (P < 0.05). 相似文献