共查询到20条相似文献,搜索用时 31 毫秒
1.
Roberta Masella Claudio Giovannini Rosaria Varì Roberta Di Benedetto Ettore Coni Roberto Volpe Nadia Fraone Antonello Bucci 《Lipids》2001,36(11):1195-1202
The aim of this study was to assess the effects of the dietary intake of extra virgin olive oil on the oxidative susceptibility
of low density lipoproteins (LDL) isolated from the plasma of hyperlipidemic patients. Ten patients with combined hyperlipidemia
(mean plasma cholesterol 281 mg/dL, triglycerides 283 mg/dL) consumed a low-fat, low-cholesterol diet, with olive oil (20
g/d) as the only added fat, with no drug or vitamin supplementation for 6 wk. Then they were asked to replace the olive oil
they usually consumed with extra virgin olive oil for 4 wk. LDL were isolated at the beginning, and after the 4 wk of dietary
treatment. LDL susceptibility to CuSO4-mediated oxidation was evaluated by measuring the extent of lipid peroxidation. We also determined fatty acid composition
and vitamin E in plasma and LDL and plasma phenolic content. Extra virgin olive oil intake did not affect fatty acid composition
of LDL but significantly reduced the copper-induced formation of LDL hydroperoxides and lipoperoxidation end products as well
as the depletion of LDL linoleic and arachidonic acid. A significant increase in the lag phase of conjugated diene formation
was observed after dietary treatment. These differences are statistically correlated with the increase in plasma phenolic
content observed at the end of the treatment with extra virgin olive oil; they are not correlated with LDL fatty acid composition
or vitamin E content, which both remained unmodified after the added fat change. This report suggests that the daily intake
of extra virgin olive oil in hyperlipidemic patients could reduce the susceptibility of LDL to oxidation, not only because
of its high monounsaturated fatty acid content but probably also because of the antioxidative activity of its phenolic compounds. 相似文献
2.
Antioxidant capacity of extra-virgin olive oils 总被引:1,自引:1,他引:0
Paolino Ninfali Gianfranca Aluigi Mara Bacchiocca Mauro Magnani 《Journal of the American Oil Chemists' Society》2001,78(3):243-247
In this study, the oxygen radical absorbance capacity (ORAC) of vegetable oils was investigated using a spectrofluorometric
method, which measures the protection of the phenolic substances of the oil on the β-phycoerythrin fluorescence decay in comparison
with Trolox. More than 97% of the phenolic substances was extracted from the oil using methanol, and the methanolic extract
was then used for the ORAC and the total phenolics assay. We found a significant correlation between ORAC values of different
olive oils and the total amount of phenolics. For extra-virgin olive oils, maximal ORAC values reached 6.20±0.31 μmol Trolox
equivalent/g, while refined and seed oils showed values in the 1–1.5 μmol Trolox equivalent/g range. Our method is useful
to assess the quality of olive oils and to predict, in combination with the rancidity tests, their stability against oxidation. 相似文献
3.
Coni E Di Benedetto R Di Pasquale M Masella R Modesti D Mattei R Carlini EA 《Lipids》2000,35(1):45-54
On the basis of the results obtained with pilot studies conducted in vitro on human low density lipoprotein (LDL) and on cell cultures (Caco-2), which had indicated the ability of certain molecules
present in olive oil to inhibit prooxidative processes, an in vivo study was made of laboratory rabbits fed special diets. Three different diets were prepared: a standard diet for rabbits
(diet A), a standard diet for rabbits modified by the addition of 10% (w/w) extra virgin olive oil (diet B), a modified standard
diet for rabbits (diet C) differing from diet B only in the addition of 7 mg kg−1 of oleuropein. A series of biochemical parameters was therefore identified, both in the rabbit plasma and the related isolated
LDL, before and after Cu-induced oxidation. The following, in particular, were selected: (i) biophenols, vitamins E and C,
uric acid, and total, free, and ester cholesterol in the plasma; (ii) proteins, triglycerides, phospholipids, and total, free,
and ester cholesterol in the native LDL (for the latter, the dimensions were also measured); (iii) lipid hydroperoxides, aldehydes,
conjugated dienes, and relative electrophoretic mobility (REM) in the oxidized LDL (ox-LDL). In an attempt to summarize the
results obtained, it can be said that this investigation has not only verified the antioxidant efficacy of extra virgin olive
oil biophenols and, in particular, of oleuropein, but has also revealed a series of thus far unknown effects of the latter
on the plasmatic lipid situation. In fact, the addition of oleuropein in diet C increased the ability of LDL to resist oxidation
(less conjugated diene formation) and, at the same time, reduced the plasmatic levels of total, free, and ester cholesterol
(−15, −12, and −17%, respectively), giving rise to a redistribution of the lipidic components of LDL (greater phospholipid
and cholesterol amounts) with an indirect effect on their dimesions (bigger by about 12%). 相似文献
4.
We investigated the changes in human LDL primary and secondary lipid oxidation products and modification of the apolipoprotein
B-100 (apoB-100) secondary structures during Cu2+-mediated oxidation by FTIR spectroscopy in the presence of catechin, quercetin, and α-tocopherol at physiological concentrations.
Catechin- and quercetin-containing samples had slower rates and longer lag phases for conjugated diene hydroperoxide (CD)
formation than α-tocopherol-containing samples; however, all antioxidant-treated LDL samples generated similar CD levels (P<0.05). A lower maximum (98.4 nmol/mg LDL protein) of carbonyl compounds was produced in the quercetin- and catechin-treated
samples than in α-tocopherol samples. Modification of the apoB-100 secondary structures corresponded closely to the formation
of carbonyls and was hampered by the presence of antioxidants. Physiological concentrations of catechin and quercetin offered
similar levels of protection against modification by carbonyls of the apoB-100 at advanced stages (carbonyls ∼96.0 nmol/mg
LDL protein) but not at the intermediate stages (carbonyls ∼58.0 nmol/mg LDL protein) of LDL oxidation probably owing to differences
in the protein-binding mechanisms of catechin and quercetin. Relationships between peroxide formation, carbonyl products,
and LDL protein denaturation were shown by the FTIR approach. The FTIR technique provided a simple new tool for a comprehensive
evaluation of antioxidant performance in protecting LDL during in vitro oxidation. 相似文献
5.
Oxidation of LDL contributes to endothelial dysfunction and atherosclerosis. This process could be associated with hyperhomocysteinemia,
a condition that can be reduced after folic acid treatment. Because a reduction in LDL oxidation may improve endothelial function,
we studied the effect of some vitamins (folic acid, 5-methyltetrahydrofolic acid, and vitamin B-12) on LDL oxidation, either
in the presence or absence of homocysteine. For this purpose, two in vitro systems were used: an endothelial cell-catalyzed LDL oxidation system and a cell-free copper-initiated LDL oxidation system.
The kinetics of coppercatalyzed LDL oxidation was determined by continuous monitoring of the production of conjugated dienes
in the reaction medium. TBARS production, a parameter of lipid peroxidation, was also evaluated. In both in vitro systems, only 5-methyl-tetrahydrofolic acid was able to decrease TBARS production in a concentration-dependent manner, independently
of the presence or absence of homocysteine. In the copper-induced LDL oxidation system, vitamin B-12 and 5-methyltetrahydrofolic
acid increased the lag time of conjugated diene production by 25 and 47%, respectively, suggesting that both vitamins in this
system had antioxidant properties. Folic acid was unable to show antioxidant properties when included in either in vitro system. The results demonstrate that 5-methyltetrahydrofolic acid and vitamin B-12 are important protective agents against
LDL oxidative modifications. 相似文献
6.
Fenofibrate protects lipoproteins from lipid peroxidation: Synergistic interaction with α-tocopherol
Evelyne Chaput Dominique Maubrou-Sanchez François D. Bellamy Alan D. Edgar 《Lipids》1999,34(5):497-502
One of the earliest steps of atherosclerotic plaque formation is an increase of circulating apolipoprotein B-containing lipoproteins
which, after infiltrating the subendothelial space, undergo oxidative modification. Fenofibrate is an effective cholesterol-
and triglyceride-lowering agent which has been shown to be beneficial in the treatment of atherosclerosis. Vitamin E, or α-tocopherol,
is a powerful antioxidant which has been shown in a variety of studies to prevent lipoprotein peroxidation. The purpose of
the present study was to investigate the effect of fenofibrate treatment, either alone or in combination with α-tocopherol,
in reducing the susceptibility of lipoproteins to oxidative modification. Rats fed a normal diet were treated for up to 27
d with fenofibrate, either alone or in combination with equimolar doses of α-tocopherol. Combined VLDL (very low density lipoproteins)
and LDL (low density lipoproteins) isolated after fenofibrate treatment were more resistant to coppermediated oxidation, as
assessed by conjugated diene formation. Lag time was prolonged up to 3.2-fold, while the maximal rate of diene production
was significantly decreased by up to 2.2-fold. Treatment of rats with α-tocopherol alone at the selected dose had no significant
effect on lag time, while the propagation rate was slightly decreased. Coadministration of fenofibrate with α-tocopherol prolonged
the lag phase to a greater extent than fenofibrate alone, showing a synergistic interaction between the two compounds. Finally,
the combination of fenofibrate and α-tocopherol was significantly more effective in modifying lipoprotein oxidation parameters
than what was observed with α-tocopherol and bezafibrate or gemfibrozil. Thus, in addition to its well-established effects
on lipoprotein concentrations and atherogenic parameters, fenofibrate reduces the susceptibility of VLDL and LDL to oxidative
modification and exerts its action synergistically with α-tocopherol. 相似文献
7.
Antioxidant activity of grape extracts in a lecithin liposome system 总被引:15,自引:0,他引:15
Ock-Sook Yi Anne S. Meyer Edwin N. Frankel 《Journal of the American Oil Chemists' Society》1997,74(10):1301-1307
Extracts of 14 different grapes were tested for their antioxidant activities in a copper-catalyzed lecithin liposome oxidation
assay and analyzed for their phenolic components by high-performance liquid chromatography (HPLC). The total phenolic contents
of the grape extracts varied from 176 to 1236 mg gallic acid equivalents (GAE)/L. Extracts of red wine grape varieties contained
higher concentrations of phenolics than other varieties. When compared at the same 20 μM GAE basis, the grape extracts inhibited
formation of conjugated diene hydroperoxides by 25.1 to 67.9%, and hexanal formation by 49.3 to 97.8%. Extracts of red table
grape varieties Red Globe and Emperor and white wine grape varieties Chardonnay and Sauvignon Blanc gave the highest antioxidant
activities. The relative percentage inhibition of conjugated dienes and hexanal correlated with total phenols (r=0.86 and 0.89). HPLC analyses showed that anthocyanins were the most abundant phenolic compounds in extracts of red grapes,
and flavonols were most abundant in extracts of white grapes. 相似文献
8.
Oxidation resistance (OR) of low density lipoproteins (LDL) is frequently determined by the conjugated diene (CD) assay, in
which isolated LDL is exposed to Cu2+ as prooxidant in the range of 1–10 μM. A brief review on major findings obtained with this assay will be given. A consistent
observation is that vitamin E supplements or oleic acid-rich diets increase OR. Oxidation indices measured by the CD assay
and effects of antioxidants very significantly depend on the Cu2+ concentration used for LDL oxidation. For medium and high Cu2+ concentrations, the relationship between lag time and propagation rate can be described by a simple hyperbolic saturation
function, which has the same mathematical form as the Michaelis-Menten equation. At medium and high Cu2+ concentrations (0.5 to 5 μM), vitamin E increases lag time in a dose-dependent manner. The increase is higher for 0.5 μM
Cu2+ as compared to 5 μM. At low Cu2+ concentrations (0.5 μM or less), the mechanism of LDL oxidation changes. Significant oxidation occurs in a preoxidation phase,
which commences shortly after addition of Cu2+. Preoxidation is not inhibited by vitamin E. It is concluded that much additional work is needed to validate the importance
of oxidation indices derived from CD and similar assays. 相似文献
9.
Ioannis Lambropoulos Ioannis G. Roussis 《European Journal of Lipid Science and Technology》2007,109(6):623-628
The antioxidant activity of Xinomavro red wine phenolic extracts in corn oil stripped of tocopherols was evaluated. One wine extract, at 100 mg/L total phenolics, rich in phenolic acids and flavonols, inhibited the oxidation of corn oil stripped of tocopherols to a greater extent than butylated hydroxyanisole, at 200 mg/L. Moreover, another extract, at 100 mg/L total phenolics, rich in flavanols, flavonols and tyrosol, also exhibited high inhibitory action. The present results indicate that some red wine phenolics – such as phenolic acids, flavonols or flavanols – may be strong antioxidants in corn oil. 相似文献
10.
Antioxidant Phenolics of Millet Control Lipid Peroxidation in Human LDL Cholesterol and Food Systems
Anoma Chandrasekara Fereidoon Shahidi 《Journal of the American Oil Chemists' Society》2012,89(2):275-285
Phenolic extracts from seven millet varieties, namely kodo, finger (Ravi), finger (local), proso, foxtail, little and pearl
were evaluated for their inhibitory effects on lipid peroxidation in in-vitro copper-mediated human LDL cholesterol oxidation
and several food model systems, namely cooked comminuted pork, stripped corn oil, and linoleic acid emulsion. The total phenolic
content (TPC) and free radical scavenging activities were measured. The TPC ranged from 146 to 1156 μmol ferulic acid equiv
(FAE)/g crude extract and the corresponding values based on defatted weight of grain ranged from 8.6 to 32.4 μmol FAE/g. At
a final concentration of 0.05 mg/mL, millet extracts inhibited LDL cholesterol oxidation by 1–41%. All seven varieties exhibited
effective inhibition of lipid oxidation in food systems used in this study and kodo millet exhibited superior inhibition of
lipid peroxidation, similar to butylated hydroxyanisole at 200 ppm. Thus, millets may serve as a natural source of antioxidants
in food applications and as a nutraceutical and functional food ingredient in health promotion and disease risk reduction. 相似文献
11.
Reza Farhoosh Mohammad Hossein Haddad Khodaparast Ali Sharif Seyedeh‐Zohreh Hoseini‐Yazdi Atefeh Zamani‐Ghalehshahi 《European Journal of Lipid Science and Technology》2012,114(11):1284-1291
Total amounts of conjugated diene hydroperoxides and carbonyl compounds of a virgin olive oil (VOO) and its purified form as affected by 0.1–6% w/w bene kernel (BKO) and hull (BHO) oils were monitored during 16 h heating at 180°C. The VOO was more prone to the production of off‐flavour carbonyl compounds than to the formation of conjugated diene hydroperoxides. The VOOs oxidative stability decreased significantly due to the removal of the indigenous antioxidative compounds. Oxidative stability, especially regarding the secondary oxidation, significantly improved with increasing concentrations of the BKO than with those of the BHO. 相似文献
12.
Fitó M Gimeno E Covas MI Miró E López-Sabater Mdel C Farré M de lT Marrugat J 《Lipids》2002,37(3):245-251
It is generally believed that virgin olive oil consumption has beneficial effects, but little is known about its effects postprandially
on oxidant/antioxidant status. The aim of this study was to determine changes in oxidative stress biomarkers and lipid profile
after a single dose of virgin olive oil and after 1 wk of daily consumption. Sixteen subjects (9 men, 7 women) ingested 50
mL of virgin olive oil in a single dose. Blood samples were collected from 0 to 24 h. Thereafter, 14 participants (8 men,
6 women) followed a 1-wk 25 mg/d virgin olive oil dietary intervention. Blood samples were collected at the end of this period.
Serum TAG (P=0.016), plasma FA (P<0.001) and lipid peroxidation products in plasma (P<0.001) and VLDL (P=0.007) increased, reaching a peak at 4–6 h, and returning to baseline values at 24 h after oil ingestion. The opposite changes
were observed in plasma glutathione peroxidase (P=0.001) and glutathione reductase (GR) (P=0.042). No changes in LDL lipid peroxidation or resistance to oxidation were observed postprandially. At 24 h, plasma oleic
acid remained increased (P<0.05) and resistance of LDL to oxidation improved (P<0.05). After 1 wk of virgin olive oil consumption, plasma oleic acid (P=0.031), resistance of LDL to oxidation (P<0.05), and plasma GR activity (P=0.005) increased. These results indicate that changes in oxidant/antioxidant status occur after oral virgin olive oil. Virgin
olive oil consumption could provide short-term benefits for LDL resistance to oxidation and in glutathione-related enzyme
activities. 相似文献
13.
Paula Jimenez Lilia Masson Andrés Barriga Jorge Chávez Paz Robert 《European Journal of Lipid Science and Technology》2011,113(4):497-505
The effect of the addition of olive leaf (Olea europaea, cv. Arbequina) extracts, i.e. hydroalcoholic (ethanol–water 1:1; OHE), juice (OJ) and supercritical fluid‐CO2 (OSFE) on the oxidative stability of vegetable oils with different unsaturation, such as soybean oil (SBO), canola oil (CO) and high oleic sunflower oil (HOSO), were studied at two concentrations (250 and 630 mg/kg oil, expressed as caffeic acid equivalent (CAE)). The extracts were characterized by the total phenolic content (Folin–Ciocalteau method), phenol chromatographic profiles (LC‐MS) and antioxidant activity (DPPH). OHE showed the highest phenol content (7.7 mg CAE/mL) while OJ and OSFE showed values of 5.4 and 2.2 mg CAE/mL, respectively. Oleuropein and its derivatives were the major phenolic compounds identified in OHE. The addition of 630 mg CAE/kg oil of OHE and OSFE to HOSO, SBO and CO showed an antioxidant effect, increasing significantly the induction time (IT) (p<0.05). That effect was highest when the system was more monounsaturated. In contrast, OJ showed a pro‐oxidant effect for all oils systems for both concentration studied. This behaviour could be attributed to the diphenol oxidase (PPO) activity. 相似文献
14.
Anu M. Turpeinen Georg Alfthan Liisa Valsta Eino Hietanen Jukka T. Salonen Hanna Schunk Kristiina Nyyssönen Marja Mutanen 《Lipids》1995,30(6):485-492
The effects of natural mixed diets on lipid peroxidation were investigated in humans. In the first study, 59 subjects were
fed a rapeseed oil-based diet rich in monounsaturated fatty acids (MUFA) and a sunflower oil-based diet rich in polyunsaturated
fatty acids (PUFA) in a cross-over manner for three and a half weeks. The lipid peroxidation products in plasma were determined
by measuring conjugated dienes and malondialdehyde (MDA). In a second study, plasma thiobarbituric acid reactive substances
(TBARS), lipid hydroperoxides, and the susceptibility of very low density lipoprotein + low-density lipoprotein (LDL) toin vitro oxidation were measured from subjects fed similar MUFA and PUFA diets for six week diets. No significant differences in plasma
MDA or conjugated diene concentrations were found after the rapeseed oil diet or the sunflower oil diet in Study 1. In the
second study, a small but significant decrease (P<0.05) in both lipid hydroperoxides and TBARS was observed in the LDL fraction after the sunflower oil diet. Thein vitro oxidation gave opposite results, showing increased oxidation after the sunflower oil diet. Despite a high intake of α-tocopherol
during the oil peroids, no increase in plasma α-tocopherol was noticed in either study. The results suggest that moderate
changes in the fatty acid composition in the Western-type diet may be adequate to affect lipoprotein susceptibility to oxidationin vitro, but there is considerable disparity with some indices ofin vivo lipid peroxidation. 相似文献
15.
Supeenun Unchern Narumon Laohareungpanya Yupin Sanvarinda Kovit Pattanapanyasat Pansakorn Tanratana Udom Chantharaksri Nathawut Sibmooh 《Lipids》2010,45(7):627-633
Oxidative modification of low-density lipoprotein (LDL) has been reported in thalassemia, which is a consequence of oxidative
stress. However, the levels of oxidized high-density lipoprotein (HDL) in thalassemia have not been evaluated and it is unclear
whether HDL oxidation may be linked to LDL oxidation. In this study, the levels of total cholesterol, iron, protein, conjugated
diene (CD), lipid hydroperoxide (LOOH), and thiobarbituric acid reactive substances (TBARs) were determined in HDL from healthy
volunteers and patients with β-thalassemia intermedia with hemoglobin E (β-thal/Hb E). The protective activity of thalassemic
HDL on LDL oxidation was also investigated. The iron content of HDL2 and HDL3 from β-thal/HbE patients was higher while the cholesterol content was lower than those in healthy volunteers. Thalassemic
HDL2 and HDL3 had increased levels of lipid peroxidation markers i.e., conjugated diene, LOOH, and TBARs. Thalassemic HDL had lower peroxidase
activity than control HDL and was unable to protect LDL from oxidation induced by CuSO4. Our findings highlight the oxidative modification and poor protective activity of thalassemic HDL on LDL oxidation which
may contribute to cardiovascular complications in thalassemia. 相似文献
16.
Reza Farhoosh Mohammad Hossein Haddad Khodaparast Ali Sharif 《European Journal of Lipid Science and Technology》2009,111(12):1259-1265
Fatty acid composition, peroxide value, acid value, iodine value, saponification number, unsaponifiable matter content, total tocopherols and phenolics contents, and wax content of Bene hull oil (BHO) were determined and compared to those of Bene kernel oil (BKO) and extra‐virgin olive oil (EVOLO). Considering the fatty acid composition and total tocopherols and phenolics contents, the resistance to the production of conjugated diene hydroperoxides and carbonyl compounds during the heating process at 170 °C for BHO was about 4.2 and 7.3 times and about 1.7 and 2.0 times those of BKO and EVOLO, respectively. The antioxidant activity of BHO was exactly the same as that of tert‐butylhydroquinone at low concentrations (100 ppm). 相似文献
17.
This study was conducted to develop a quantitative FTIR spectroscopy method to measure LDL lipid oxidation products and determine
the effect of oxidation on LDL lipid and protein. In vitro LDL oxidation at 37°C for 1 h produced a range of conjugated diene (CD) (0.14–0.26 mM/mg protein) and carbonyl contents (0.9–3.8
μg/g protein) that were used to produce calibration sets. Spectra were collected from the calibration set and partial least
squares regression was used to develop calibration models from spectral regions 4000-650, 3750-3000, 1720-1500, and 1180-935
cm−1 to predict CD and carbonyl contents. The optimal models were selected based on their standard error of prediction (SEP),
and the selected models were performance-tested with an additional set of LDL spectra. The best models for CD prediction were
derived from spectral regions 4000-650 and 1180-935 cm−1 with the lowest SEP of 0.013 and 0.013 mM/mg protein, respectively. The peaks at 1745 (cholesterol and TAG ester C=O stretch),
1710 (carbonyl C-O stretch), and 1621 cm−1 (peptide C=O stretch) positively correlated with LDL oxidation. FTIR and chemometrics revealed protein conformation changes
during LDL oxidation and provided a simple technique that has potential for rapidly observing structural changes in human
LDL during oxidation and for measuring primary and secondary oxidation products. 相似文献
18.
The purpose of the present paper is to study and compare in vitro the inhibitory effect of 3,4-dihydroxyphenylacetic acid (DOPAC) and caffeic acid (CA) on lipid peroxidation in rat plasma.
Rat plasma was oxidized at 37°C by the radical initiators 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) or 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile)
(MeO-AMVN). The consumption of endogenous α-tocopherol (α-TOH) and the accumulation of conjugated diene hydroperoxides were
measured by high-performance liquid chromatography and by ultraviolet spectroscopy, respectively. α-TOH was consumed at the
same rate in the presence of 20 mM AAPH or 2 mM MeO-AMVN. DOPAC and CA suppressed the α-TOH consumption in a dose-dependent
manner. A concentration of 50 μM of both phenolic acids was sufficient to induce a lag phase and to delay the rate of α-TOH
consumption. The effect was more pronounced in rat plasma oxidation by AAPH than by MeO-AMVN. CA spared vitamin E more effectively
than DOPAC in both oxidations. DOPAC and CA suppressed the formation of conjugated diene hydroperoxides. DOPAC and CA at concentration
50 μM suppressed α-TOH consumption during oxidation of soybean phosphatidylcholine (2.8 mM) multilamellar vesicles containing
15 μM α-TOH, in which the lipophilic initiator 2,2′-azobis (2,4-dimethylvaleronitrile) (6 mM) was incorporated. In conclusion,
we demonstrated that DOPAC and CA in micromolar concentrations have antioxidant activity in rat plasma, a medium very close
to the conditions in vivo, suggesting that supplementation with the phenolic acids will provide significant antioxidant protection. 相似文献
19.
Saskia M. van Ruth Jacques P. Roozen Maarten A. Posthumus Frans Jos H. M. Jansen 《Journal of the American Oil Chemists' Society》1999,76(11):1375-1381
The formation of conjugated diene hydroperoxides and hexanal was compared to the development of aroma profiles during initial
lipid oxidation of a vegetable oil and its 40% oil-in-water emulsion at 60°C. The aroma profiles of the oil and the emulsion
with and without addition of ascorbic acid or ascorbyl palmitate were compared. The aroma compounds were isolated under a
model mouth system and analyzed by gas chromatography/sniffing port analysis. Detectable odors were found and corresponded
to 11 and 14 volatile compounds in the oil and the emulsion, respectively. The emulsion had higher lipid oxidation rates than
the oil. Addition of ascorbic acid and ascorbyl palmitate had little influence on the aroma composition of the oil. In the
emulsion, addition of these compounds resulted in diminished generation of odor active compounds. Results of measurements
of conjugated diene hydroperoxides and headspace hexanal corresponded to that of the lipid oxidation rate in general, but
predicted insufficiently the alterations in the aroma compositions by antioxidants. 相似文献
20.
An animal feeding trial was conducted to investigate whether olive oil phenolics can act as functional antioxidants in vivo. To this end, hamsters were exposed for a period of 5 wk to a dietary regime with either a phenol-rich extra virgin olive
oil or extra virgin olive oil from which phenols were removed by ethanol/water-washing. The original oil used in the high
olive phenol diet was also used for the preparation of the low phenol diet in order to keep the FA compositions exactly the
same. In addition, the vitamin E content was kept identical in both diets. This careful preparation of the diets was undertaken
in order to prevent these factors from influencing the antioxidative status in plasma and LDL. Removal of olive oil phenols
was shown to reduce both the vitamin E level in plasma and the resistance of LDL to ex vivo oxidation. The results of this study support the idea that extra virgin olive oil phenols improve the antioxidant defense
system in plasma by sparing the consumption of vitamin E under normal physiological circumstances. 相似文献