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1.
R. J. Hamilton C. Kalu G. P. McNeill F. B. Padley J. H. Pierce 《Journal of the American Oil Chemists' Society》1998,75(7):813-822
The effects of α-, γ/δ, and δ-tocopherol concentrates (0.2–2.0%) alone and in combination with ascorbyl palmitate (0.1%) and
lecithin (0.5%) on oxidative stability and flavor of fish oil were studied. Stability was assessed on oil stored in air at
20°C by peroxide value (PV) and off-flavor formation. Polymer content, para-anisidine value, and conjugation were used to characterize selected samples. When used alone, the protective effect of the
tocopherols, as measured by PV, was δ≫γ/δ≫α, especially at the 2% concentration. Binary systems of ascorbyl palmitate-lecithin
and lecithin-γ/δ or-δ-tocopherol were strongly synergistic in delaying peroxidation. The ternary blends provided the greatest
protection against autoxidation. Refined fish oil with 2% δ-tocopherol, 0.1% ascorbyl palmitate, and 0.5% lecithin showed
no significant peroxidation at 20°C over a period of 6 mon. The original antioxidant effect noted for the ternary systems
in delaying peroxidation was not reflected in improved flavor stability. Off-flavors developed within 3 wk, making the oils
unsuitable for use at high concentrations in ambient products that are unprotected from air. 相似文献
2.
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
3.
Antioxidant activity of rapeseed phenolics and their interactions with tocopherols during lipid oxidation 总被引:1,自引:0,他引:1
Commercial rapeseed press cakes are rich sources of phenolic compounds, namely, sinapic acid derivatives, which can be extracted
as free sinapic acid and its bound forms (such as sinapine, the choline ester of sinapic acid). Fractionated rapeseed extracts
rich in sinapic acid and sinapine were compared for their capacity to inhibit the formation of lipid oxidation products. Oxidation
at 40°C was monitored by the formation of hydroperoxides (indicating primary oxidation products) and propanal (secondary oxidation
products). The 70% methanolic extract of rapeseed meal, added as an equivalent of 500 μmol/kg oil (based on sinapic acid equivalent
for sinapic acid-rich extracts or sinapine equivalent for sinapinerich extracts) showed good antioxidative activity compared
with the addition of 500 μmol/kg oil sinapic acid. Apart from this, the interaction between a mixture of α-/γ-tocopherol and
sinapic acid was investigated using response surface methodology for the experimental design. The experiments indicated that
the addition of sinapic acid (concentration dependent) caused inhibition of peroxide formation, complementing further lower
endogenous tocopherol concentration in oils.
This paper was initially presented at the 95th AOCS Annual Meeting and Expo in Cincinnati, Ohio, May 1–4, 2004. 相似文献
4.
脂肪酶催化合成棕榈酸维生素C酯的研究 总被引:2,自引:0,他引:2
在溶剂相中,用固定化脂肪酶催化合成棕榈酸维生素C酯。研究了反应体系含水量、溶剂、反应温度、加酶量、加入分子筛等因素对反应的影响。结果表明,最佳反应条件为:Novo 435脂肪酶用量为反应物质量的4%,叔丁醇作溶剂,反应温度55℃,摇床转速200 r/min,反应时间36 h,转化率52%,产品纯度95%。 相似文献
5.
建立了同时测定化妆品中3-O-乙基抗坏血酸和抗坏血酸棕榈酸酯的分析方法。样品用甲醇提取剂提取后经反相C_(18)柱(4.6×250 mm,5μm)分离,采用0.05%磷酸-乙腈作为流动相,梯度洗脱,流速为1.0 mL/min,二极管阵列检测器进行检测,检测波长为245 nm和240 nm,外标法定量。在优化的实验条件下,3-O-乙基抗坏血酸在1~100 mg/L线性关系良好,在空白样品中添加10、50、100 mg/kg 3个浓度水平时,得到的回收率为95%~103%,相对标准偏差为3.1%~5.9%。方法的检出限(S/N=3)为3.0 mg/kg,定量限(S/N=10)为10.0mg/kg;抗坏血酸棕榈酸酯在2~200mg/L线性关系良好,在空白样品中添加20、100、200 mg/kg 3个浓度水平时,得到的回收率为98%~104%,相对标准偏差为2.7%~4.6%。方法的检出限(S/N=3)为6.0 mg/kg,定量限(S/N=10)为20.0 mg/kg。 相似文献
6.
Jenifer A. Lindsey Hanfang Zhang Hisayuki Kaseki Nobuhiro Morisaki Takasi Sato David G. Cornwell 《Lipids》1985,20(3):151-157
The antioxidant capacities of α- and γ-tocopherols (α-E and γ-E) and their quinones (α-EQ and γ-EQ) were determined in non-biological
and biological systems. The non-biological system consisted of arachidonic acid [20∶4 (n−6)], the oxidant cumene hydroperoxide,
and a Fe3+ catalyst to facilitate malondialdehyde (MDA) formation from lipid peroxides. α-E and γ-E had similar antioxidant capacities
in this system. α-EQ also functioned as an antioxidant, while γ-EQ exhibited a crossover effect by functioning as an antioxidant
at low concentrations and a prooxidant at high concentrations. Biological lipid peroxidation in smooth muscle cells challenged
with 20∶4 (n−6) was measured both by MDA formation in confluent cultures and by cell growth in proliferating cultures. α-E,
γ-E and α-EQ had similar antioxidant capacities, but γ-EQ was highly cytotoxic for cells in both confluent and proliferating
cultures. Cellular retention of antioxidants was estimated indirectly from MDA formation when cells were loaded with an antioxidant
(preincubation) and then incubated for varying periods of time in fresh media containing 20∶4 (n−6). Cellular retention also
was measured directly with tritiated α-E and tritiated αEQ. These studies showed that cellular retention decreased in the
sequence γ-E>α-E>α-EQ. Thus, cellular retention does not explain the enhanced antioxidant capacity of α-E compared to γ-E
that has been reported for animal systems. The antioxidant capacity of αE evidently is enhanced by its metabolism to a quinone
which, unlike the quinone from γ-E, functions as a biological antioxidant. 相似文献
7.
S. Bradoo R. K. Saxena R. Gupta 《Journal of the American Oil Chemists' Society》1999,76(11):1291-1295
High yields of ascorbyl palmitate (6-O-palmitoyl-l-ascorbic acid) were obtained by lipase-mediated esterification using Bacillus stearothermophilus SB 1 lipase. The final yield was greatly influenced by the initial water content of the system, quantity of enzyme, and molar
ratio of palmitic acid to l-ascorbic acid. Reaction rates increased directly with temperature from 40 to 100°C. Maximum conversion (97%) was achieved
after 30 min at 100°C (solvent-free), 1 h at 80°C (solvent-free), and 2 h at 60°C (solvent/hexane). The synthesis was scaled
up to 1-l volume with 95% conversion using 50 mmoles of ascorbic acid and 250 mmoles of palmitic acid in hexane. Similar yields of
ester were obtained in five repetitive cycles using 5 g enzyme immobilized on Accurel. The present B. stearothermophilus SB 1 lipase was a more efficient catalyst for the synthesis of ascorbyl palmitate than other commercial lipases. 相似文献
8.
Cod liver oil (CLO) with no added antioxidants (REF), 200 mg/kg ascorbyl palmitate (AP), and/or 800 mg/kg tocopherol concentrate
(TOH) were stored in sealed bottles with a small headspace of air at 25°C in the dark. A binary mix of TOH +AP affected the
sensory perception of CLO by leading to a more grass/cucumber-like and less herring oil-like impression, whereas TOH alone
had no effect. This was caused by the different influence of the antioxidants with regard to formation of volatile oxidation
products. TOH+AP promoted formation of, e.g., hexanal, 2-hexenal, and 2,6-nonadienal and inhibited formation of, e.g., 2,4-heptadienal.
TOH affected the proportions of trans, cis-and trans,trans-2,4-heptadienal that were formed and inhibited formation of, e.g., 1-penten-3-ol, whereas formation of acetic acid and some
other volatiles was inhibited by both antioxidants. The total amount of volatiles increased during the experiment, and with
REF were significantly higher (P<0.05) than with TOH. The PV increased during the first 2 wk of storage. PV levels were in the order of TOH>REF>TOH+AP. The
observed effects could partly be explained by hydrogen donation from TOH to peroxyl radicals, but the mode of action for AP
was unclear. 相似文献
9.
10.
Thelma S. Vicente Edward H. Waysek Winifred M. Cort 《Journal of the American Oil Chemists' Society》1985,62(4):745-747
An HPLC method for the determination of ascorbyl palmitate in vegetable oil and lard has been developed. Chromatographic conditions consist of a diamine column, a mobile phase of 70:30 (v/v) methanol:0.02M monobasic potassium phosphate buffer, pH 3.5, and UV detection. Samples were extracted with methanol. An overall average recovery value of 96.7% was obtained for ascorbyl palmitate in five representative vegetable oils and lard. 相似文献
11.
M. Baldioli M. Servili G. Perretti G. F. Montedoro 《Journal of the American Oil Chemists' Society》1996,73(11):1589-1593
The antioxidant effects of hydrophilic phenols and tocopherols on the oxidative stability in virgin olive oils and in purified
olive oil have been evaluated. Total hydrophilic phenols and the oleosidic forms of 3,4-dihydroxyphenolethanol (3,4-DHPEA)
were correlated (r=0.97) with the oxidative stability of virgin olive oil. On the contrary, tocopherols showed low correlation (r=0.05). Purified olive oil with the dialdehydic form of elenolic acid linked to 3,4-DHPEA, an isomer of oleuropeine aglycon,
and 3,4-DHPEA had good oxidative stability. A synergistic effect was observed in the mixture of 3,4-DHPEA and its oleosidic
forms with α-tocopherol in purified olive oil by the Rancimat method at 120°C. 相似文献
12.
Marjukka Mkinen Marja Khknen Anu Hopia 《European Journal of Lipid Science and Technology》2001,103(10):683-687
Effects of ascorbic acid (AA) and ascorbyl palmitate (AP) on lipid hydroperoxides were evaluated during the formation and decomposition of methyl linoleate hydroperoxides (ML‐OOH). AA and AP at 1 and 10 mM levels had no effect on the formation of ML‐OOH during the autoxidation of methyl linoleate at 40 °C. However, depending on the reaction medium, AA and AP at 0.2 and 2 mM either slightly inhibited or accelerated the decomposition of 40 mM cis, trans ML‐OOH in hexadecane or in hexadecane‐inwater emulsion. The increased decomposition rate of ML‐OOH, when compared to a control sample, was apparently due to the reductive activity of AA and AP on metal ions present in the system, as the addition of EDTA improved the stability of ML‐OOH. The more detailed analysis of the decomposition reactions of ML‐OOH suggests that under favorable reaction conditions AA and AP were, to some extent, capable of acting as hydrogen atom donors to peroxyl radicals and reducers of hydroperoxides to more stable hydroxy compounds. However, since all these effects of AA and AP on lipid hydroperoxides were relatively small, it is assumed that the antioxidative activity of AA and AP as well as their effect on the stability and reactions of lipid hydroperoxides in biological systems and in foods is mainly related to their synergistic interactions with other antioxidative compounds such as tocopherols. 相似文献
13.
Calvin Golumbic 《Journal of the American Oil Chemists' Society》1942,19(10):181-182
Summary Phosphoric acid greatly augments the antioxygenic activity of hydroquinones and tocopherols and their corresponding quinones
in autoxidizing fats. In such media,p-quinones are partly reduced to hydroquinones. Phosphoric acid promotes this reaction and thus enhances, in a synergistic
manner, the antioxygenic activity of both quinones and hydroquinones. With tocoquinones, cyclization as well as reduction
occurs, and tocopherol is thereby regenerated.
The results suggest that a hydroquinone ⇄ quinone system is set up upon the addition of either the oxidant or the reductant
to an autoxidizing fat, and that the resulting equilibrium is shifted in favor of the reductant by phosphoric acid.
Presented in part before the Division of Food and Agricultural Chemistry, American Chemical Society meeting, St. Louis, Missouri
1941. 相似文献
14.
The antioxidant effect of lecithins was tested on several oils and fats varying in FA composition and tocopherol content.
Standard lecithins, when added at a level of 1% w/w, exhibited a good protective effect against oxidation. This effect was
observed to depend on the phospholipid content of the tested lecithins and the FA composition of the tested oils. Better results
were obtained with lecithin samples containing high proportions of PC and PE. Indeed, the main antioxidant mechanism of lecithins
was due to a synergistic effect between amino-alcohol phospholipids and γ- and δ-tocopherols. No synergism was observed with
α-tocopherols, especially when the tested oil was rich in linoleic acid. Therefore, the antioxidant protection of lecithins
was not effective for sunflower oil. Finally, the use of fractionated or enriched lecithins was not clearly advantageous compared
to standard oil lecithins. 相似文献
15.
Y. -Y. Gwo G. J. Flick Jr. H. P. Dupuy R. L. Ory W. L. Baran 《Journal of the American Oil Chemists' Society》1985,62(12):1666-1671
The addition of 0.02% ascorbyl palmitate (AP) reduced color development of frying fat (animal fat/vegetable oil [A-V] shortening)
and vegetable oil (partially hydrogenated soybean [V-S] oil) in simulation studies. It also reduced peroxide values, development
of conjugated diene hydroperoxides (CDHP) and their subsequent degradation to volatile compounds, such as decanal and 2,-4
decadienal, indicating that AP has the ability to inhibit thermal oxidation/degradation of frying fats and oils. A commercial
french fry fat had lower CDHP values compared to A-V fat in simulated studies, and fried chicken oil had lower CDHP values
than the V-S oil. Peanut oil had higher thermal stability than the other fats and oils. 相似文献
16.
Effects of 0, 500, 1000, and 1500 ppm (wt/vol) ascorbyl palmitate (AP) on the methylene-blue- and the chlorophyll-sensitized
photooxidations of linoleic acid or soybean oil, either in methanol or in a solvent mixture (benzene/methanol, 4:1, vol/vol),
were studied during storage under 3300 lux fluorescent light for 5 h. Steady-state kinetic approximation was used to determine
a quenching mechanism and quenching rate constant of AP in the chlorophyll-sensitized photooxidation of methyl linoleate in
a solvent mixture (benzene/methanol, 4:1, vol/vol). Both methylene blue and chlorophyll greatly increased the photooxidation
of linoleic acid and soybean oil, as was expected. AP was extremely effective at minimizing both methylene-blue-and chlorophyll-sensitized
photooxidations of linoleic acid and soybean oil, and its effectiveness was concentration-dependent. The addition of 500,
1000, and 1500 ppm AP resulted in 69.3, 83.6, and 94.6% inhibition of methyleneblue-sensitized photooxidation of linoleic
acid, respectively, after 5-h storage under fluorescent light. AP showed significantly greater antiphotooxidative activity
than α-tocopherol for the reduction of methylene blue-sensitized photooxidation of linoleic acid (P < 0.05). The steady-state kinetic studies indicated that AP quenched singlet oxygen only to minimize the chlorophyll-sensitized
photooxidation of oils. The calculated total quenching rate of AP was 1.0 × 108 M−1s−1. The present results clearly showed, for the first time, the effective singlet oxygen quenching ability of AP for the reduction
of photosensitized oxidation of oils. 相似文献
17.
Simultaneous determination of ascorbyl palmitate and nine phenolic antioxidants in vegetable oils and edible fats by HPLC 总被引:1,自引:0,他引:1
This study describes an HPLC method for the simultaneous determination of ascorbyl palmitate (AP) and synthetic phenolic antioxidants
(SPA) in vegetable oils and edible fats in a single run. To achieve this, citric acid was used in combination with isoascorbic
acid for stabilization of AP in standard and sample solutions and for deactivation of oxidizing agents in the HPLC system.
SPA and AP were directly extracted from samples with methanol containing 1 mg/mL each of citric acid and isoascorbic acid.
HPLC analytical and guard columns were pretreated with 90% methanol/acetonitrile 1∶1 (vol/vol), containing 4 mg/mL each of
citric acid and isoascorbic acid, and 10% water at pH 3, for 30 min. Under these conditions, AP was stable for about 7 h at
room temperature. The relative SD of repeatability for AP (0.5–3.6%) was comparable to that for SPA (0.3–2.8%). Average recovery
from spiked samples was 100% for AP, 98–103% for SPA, and 85% for BHT (up to 90% using double extraction with methanol). 相似文献
18.
K. H. Lee H. S. Yook J. W. Lee W. J. Park K. S. Kim M. W. Byun 《Journal of the American Oil Chemists' Society》1999,76(8):921-925
The effects of 0, 250, 500, and 1000 ppm (wt/vol) ascorbyl palmitate (AP) on the gamma irradiation-induced oxidation of soybean
oil, cottonseed oil, corn oil, tallow, lard, or linoleic acid either in a solvent mixture (benzene/methanol, 4:1 vol/vol)
or in methanol, was studied immediately after gamma irradiation with a dose of 1–5 kGy. Steady-state kinetic approximation
was used to determine a quenching mechanism and quenching rate constant of AP on the gamma irradiation-induced oxidation of
purified soybean oil in a solvent mixture (benzene/methanol, 4:1 vol/vol). Irradiation greatly increased oxidation of all
oils, as was expected. AP was extremely effective at minimizing oxidation in all oils, and its effectiveness was concentration
dependent. AP showed significantly greater antioxidative activity than α-tocopherol for the reduction of oxidation in all
oils (P<0.05). The steady-state kinetic studies indicated that AP quenched oxygen only to minimize the oxidation of oils. The calculated
total quenching rate of AP was 7.51×107 M−1s−1. The present results clearly show the effective oxygen quenching ability of AP for the reduction of gamma irradiation-induced
oxidation of oils. 相似文献
19.
20.
Mixed tocopherols (MT) containing a predominance of γ‐tocopherol were evaluated for antioxidant (AO) performance in polybutadiene‐ and polyisoprene‐based styrenic block copolymers (SBS and SIS, respectively) by using oxidative induction time as a measure of AO performance. A conventional hindered phenolic AO and α‐tocopherol (vitamin E) were evaluated in comparison. MT exhibited significantly higher performance than the controls in both SIS and SBS polymers. J. VINYL ADDIT. TECHNOL., 12:73–77, 2006. © 2006 Society of Plastics Engineers 相似文献