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1.
Nikolaos B. Kyriakidis Theophanis Katsiloulis 《Journal of the American Oil Chemists' Society》2000,77(12):1235-1238
A new calculation method for the determination of iodine value (IV) from measurements of fatty acid methyl esters is proposed.
The method is based on the quantitative determination of fatty acid methyl esters of vegetable oils by capillary gas chromatography.
IV is a measure of the number of double bonds in the unsaturated fatty acids in one gram of oil. The analytical methodology
of its evaluation includes the use of rather health dangerous reagents, and for that reason is mostly avoided by laboratory
analysts. A calculation procedure to determine the IV of oils from their fatty acid methyl ester composition is in use based
on the American Oil Chemists’ Society (AOCS) method Cd 1c-85. A new calculation procedure for IV, based also on the evaluation
of the fatty acid methyl esters of oils, was developed. The application of the proposed calculation methodology was checked
with olive oil, corn oil, soybean oil, cottonseed oil, and sunflower seed oil. The proposed calculation gave results in better
agreement with the Wijs method than with the relevant AOCS method. 相似文献
2.
Pan-frying stability of NuSun oil,a mid-oleic sunflower oil 总被引:3,自引:3,他引:0
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
3.
Development of steryl ester analysis for the detection of admixtures of vegetable oils 总被引:2,自引:0,他引:2
Michael H. Gordon Luke A. D. Miller 《Journal of the American Oil Chemists' Society》1997,74(5):505-510
The steryl ester content and composition of 28 samples from 10 vegetable oil types have been determined by isolation of the
steryl esters by high-performance liquid chromatography and analysis by gas chromatography. The oils can be classified into
oils with a high content (>4000 mg/kg) of steryl esters (corn and rapeseed); oils with a medium content (1400–2400 mg/kg)
of steryl esters (sunflower oil and high-oleic sunflower oil); and oils with a low content (<1200 mg/kg) of steryl esters
(safflower, soybean, cottonseed, groundnut, olive, and palm oils). The composition of the steryl ester fraction varies to
a greater extent for different oil types than for different varieties of the same oilseed. The developed method is promising
for authentication of some oils, and is particularly suitable for detecting admixtures of low levels of corn or rapeseed oils. 相似文献
4.
A fast and cost-effective procedure to quantitate epoxidized soybean oil by means of an external standard method is reported.
This procedure is applicable to commercial epoxidized oils, polymer additive packages and polymers—polyvinyl chloride (PVC)—containing
epoxidized oils. The epoxidized soybean oil is converted into fatty acid methyl esters with tetramethylammonium hydroxide,
and analyzed by capillary gas chromatography with flame-ionization detection. In PVC samples, the epoxidized soybean oil was
extracted with toluene and followed by derivatization prior to analysis. The methyl esters of monoepoxyoctadecanoic, diepoxyoctadecanoic
and triepoxyoctadecanoic acid were separated with a short capillary column. 相似文献
5.
Inmok Lee Lawrence A. Johnson Earl G. Hammond 《Journal of the American Oil Chemists' Society》1996,73(5):631-636
Methyl soyate, made from typical soybean varieties, has a crystallization onset temperature (T
co) of 3.7°C and, as a biodiesel fuel, is prone to crystallization of its high-melting saturated methyl esters at cold operating
temperatures. Removal of saturated esters by winterization was assessed as a means of reducing theT
co of methyl soyate. Winterizing neat methyl esters of typical soybean oil produced aT
co of −7.1°C, but this was not an efficient way of removing saturated methyl esters because of the low yield (26%) of the separated
liquid fraction. However, aT
co of −6.5°C with 86% yield was obtained by winterizing the neat methyl esters of a low-palmitate soybean oil; aT
co of −5.8°C with 77% yield was obtained by winterizing methyl esters of normal soybean oil diluted with hexane. 相似文献
6.
Bleaching of alkali-refined vegetable oils with clay minerals 总被引:5,自引:0,他引:5
Keito Boki Moriaki Kubo Tetsuyuki Wada Takamichi Tamura 《Journal of the American Oil Chemists' Society》1992,69(3):232-236
Bleaching efficiencies of bentonites, montmorillonites and sepiolites for alkali-refined rapesseed, soybean, wheatgerm, safflower,
corn, cottonseed and sunflower oils were investigated by a batch method at 110°C. The sepiolites with more acid sites at −5.6
< Ho ≥ −3.0 were the most effective in bleaching of each alkali-refined oil. Surface area and acidity at −5.6>Ho ≥ −3.0 were highly significant with bleaching efficiency. The sepiolites (numbers 2 and 3) were more suitable than standard
activated clay because they were more effective both in retaining tocopherols and in reducing free fatty acids after bleaching. 相似文献
7.
Monica M. Neumann Silvia N. Fusero Norman A. García 《Journal of the American Oil Chemists' Society》1991,68(9):662-665
The susceptibilities of crude soybean, sunflower and peanut oils to singlet oxygen photooxidation were determined in a kinetic
study. The accumulation of photosensitized hydroperoxides, determined spectroscopically, and the quenching of singlet molecular
oxygen phosphorescence by the crude oils and their fatty acid methyl esters were compared.
The relative tendency to photooxidation for the oils and the methyl esters was soybean ≫ sunflower > peanut. This trend was
independent of the method employed in the determination of initial photodamaging.
Soybean oil was demonstrated to be the most unstable product, not only due to the presence of highly unsaturated fatty acids,
but also due to the absence of natural constituents, capable of providing a protective antioxidant effect. This protection
was more effective in sunflower and peanut oils. 相似文献
8.
In this study, biodiesel production from various vegetable oils by transesterification was studied, to determine the optimum conditions. Experiments were carried out by using different kinds of catalysts (sodium hydroxide, potassium hydroxide, barium hydroxide, pyrolitic coke and wood ash) and feedstocks (corn oil, sunflower oil, soybean oil, olive pomace oil and cottonseed oil) at 65 °C and an agitation speed of 1000 rpm. The neutralization step with controlled pH was performed by treatment with phosphoric acid. An experimental design was used to evaluate the effects of the parameters such as types of vegetable oils, kinds of catalysts, reaction time, alcohol/oil volumetric ratio and amount of catalyst, on the methyl ester conversion. Using response surface methodology, a quadratic polynomial equation was obtained by multiple regression analysis. It was found that catalyst concentration was the most effective parameter. Sodium hydroxide and potassium hydroxide exhibited a superior catalytic behavior, whereas pyrolitic coke and wood ash had to be used in excess amount or for prolonged reaction times. Moreover, the properties such as viscosity, density, calorific value, acid value, and refractive index of the biodiesel were measured. The tri‐, di‐, monoacylglycerols and glycerol residuals in the methyl esters produced were also quantified by GC analysis. 相似文献
9.
Tocopherols in breeding lines and effects of planting location, fatty acid composition, and temperature during development 总被引:6,自引:4,他引:2
David Dolde Chris Vlahakis Jan Hazebroek 《Journal of the American Oil Chemists' Society》1999,76(3):349-355
As the use of tocopherols as natural antioxidants increases, it is economically and agronomically important to determine the
range, composition, and factors that affect their levels in oilseed crops, a major commercial source. In this study, tocopherols
were quantified from seeds of wheat, sunflower, canola, and soybean. The breeding lines analyzed possessed a broad range of
economically important phenotypic traits such as disease or herbicide resistance, improved yield and agronomic characteristics,
and altered storage oil fatty acid composition. Complete separation of all four native tocopherols was achieved using normal-phase
high-performance liquid chromatography with ultraviolet detection. Total tocopherol concentration among wheat germ oil samples
ranged from 1947 to 4082 μg g−1. Total tocopherol concentration ranges varied from 534 to 1858 μg g−1 in sunflower, 504 to 687 μg g−1 in canola, and 1205 to 2195 μg g−1 among the soybean oils surveyed. Although the composition of tocopherols varied substantially among crops, composition was
stable within each crop. Total tocopherol concentration and the percentage linolenic acid were correlated positively in soybean
oils with modified and unmodified fatty acid compositions. Tocopherol concentration and degree of unsaturation were not correlated
in sunflower or canola seeds with genetically altered fatty acid composition. These findings suggest that breeding for altered
storage oil fatty acid composition did not negatively impact tocopherol concentrations in sunflower and canola as they apparently
did in soybeans. When 12 soybean breeding lines were grown at each of five locations, significant correlations were observed
among planting location, breeding line, tocopherol concentration, and fatty acid composition. Analysis of seeds that matured
under three different controlled temperature regimes suggests that the relationship between tocopherol concentration level
and unsaturated fatty acids in commodity (not genetically modified for fatty acid composition) oil types is due to temperature
effects on the biosynthesis of both compounds. 相似文献
10.
K. Warner C. D. Evans G. R. List H. P. Dupuy J. I. Wadsworth G. E. Goheen 《Journal of the American Oil Chemists' Society》1978,55(2):252-256
Samples of commercially processed soybean, cottonseed, and peanut oils were stored under controlled conditions then evaluated
for flavor by a 20-member trained, experienced oil panel and for pentanal and hexanal contents by direct gas chromatography.
The oils, which contained citric acid and/or antioxidants, were either aged from 0 to 16 days at 60 C or exposed to fluorescent
light for 0 to 16 hr. The simple linear regressions of flavor score with the logarithm of pentanal or hexanal content in aged
soybean oil gave correlation coefficients of −0.96 and −0.90, respectively; for cottonseed oil, −0.60 and −0.85; and for peanut
oil −0.74 and −0.75. Addition of peroxide values to the linear regressions increased the correlation coefficients. Flavor
scores of cottonseed and peanut oil can be predicted from pentanal and hexanal contents, but the technique is slightly more
reliable for soybean oil based on the treatments used for these oils.
Presented at the AOCS Meeting, Chicago, September 1973. 相似文献
11.
Low-molecular weight organic compositions of acid waters from vegetable oil soapstocks 总被引:3,自引:3,他引:0
Steven L. Johansen Arunthathi Sivasothy Michael K. Dowd Peter J. Reilly Earl G. Hammond 《Journal of the American Oil Chemists' Society》1996,73(10):1275-1286
Alkaline extracts (soapstocks) from canola, corn, cottonseed, peanut, soybean, and sunflower oil refining were acidified,
and identities and concentrations of the low-molecular weight organic components of the resulting acid waters were determined
by gas chromatography, followed by mass spectroscopy, and by high-performance liquid chromatography. The main components of
each acid water sample, in order of decreasing concentration and after omitting the fermentation product lactic acid, were
phosphoric acid, α-glycerophosphate, and glycerol from canola;myo-inositol, phosphoric acid, α-glycerophosphate andmyo-inositol-1-phosphate from corn; glycerol, α-glycerophosphate,myo-inositol-1-phosphate, and β-glycerophosphate from cottonseed; phosphoric acid, glycerol, andmyo-inositol from peanut; α-glycerophospho-1-myo-inositol,myo-inositol-1-phosphate, α-glycerophosphate, and glycerol from soybean; and α-glycerophosphate, glycerol,myo-inositol-1-phosphate, and β-glycerophosphate from sunflower. 相似文献
12.
Huayang He Shiyao Sun Tao Wang Shenlin Zhu 《Journal of the American Oil Chemists' Society》2007,84(4):399-404
A kinetic study on soybean oil transesterification without a catalyst in subcritical and supercritical methanol was made at
pressures between 8.7 and 36 MPa. It was found that the conversion of soybean oil into the corresponding methyl esters was
enhanced considerably in the supercritical methanol. The apparent activation energies of the transesterification are different
with the subcritical and the supercritical states of methanol, which are 11.2 and 56.0 kJ/mol (molar ratio of methanol to
oil: 42, pressure: 28 MPa), respectively. The reaction pressure considerably influenced the yield of fatty acid methyl esters
(FAME) in the pressure range from ambient pressure up to 25 MPa (280 °C, 42:1). The reaction activation volume of transesterification
in supercritical methanol is approximately −206 cm3/mol. The PΔV
≠ term accounts for nearly 10% of the apparent activation energy, and can not be ignored (280 °C, 42:1). 相似文献
13.
A chromatographic method is described to measure the crystallizable wax content of crude and refined sunflower oil. It can
also be applied to any other vegetable oil. The preparative liquid chromatography step on a glass column containing a silica
gel adsorbent superimposed upon a silver nitrate-impregnated silica gel support is used to isolate a wax fraction which is
then analyzed by gas chromatography. The recovered wax fraction contains, in addition to the crystallizable waxes, hydrocarbons
and other compounds with gas chromatographic retention times corresponding to waxes with chain lengths C34−C42. These compounds are short-chain saturated waxes in fruit oils, such as grapeseed and pomace. In seed oils such as sunflower,
soybean or peanut, the compounds initially referred to as “soluble esters” are identified as monounsaturated waxes, esters
of long-chain saturated fatty acids, and a monounsaturated alcohol, mainly eicosenoic alcohol. Such waxes are absent from
corn or rice bran oils. 相似文献
14.
Titipong Issariyakul Ajay K. Dalai Prabhat Desai 《Journal of the American Oil Chemists' Society》2011,88(3):391-402
Biodiesel was produced from mustard oil utilizing transesterification with methanol, ethanol, propanol, and butanol to evaluate
the characteristics of mustard biodiesel as an additive to regular diesel. Mustard oil was transesterified with alcohol at
6:1 alcohol to oil molar ratio, using KOH as a catalyst at 1 wt%. The maximum ester content achieved by this method was only
66%. Distillation was then used to purify the ester, raising the ester content to 99.8%. Alternatively, mustard oil methyl
ester (MME) can be mixed with esters derived from canola oil or soybean oil to achieve an ASTM quality biodiesel. Biodiesel
derived from mustard showed great potential as lubricity additive for regular diesel fuel. With an addition of 1% MME, lubricity
of diesel fuel was improved by 43.7%. It is also found that methyl ester is the best lubricity additive among all esters (methyl-,
ethyl-, propyl-, and butyl-ester). MME can be used at −16 °C without freezing whereas monounsaturated compounds (oleic, eicosenoic,
and erucic esters) largely present in esters derived from mustard oil can tolerate −42 to −58 °C. Monounsaturated esters derived
from higher alcohols such as butyl alcohol demonstrated a superior low temperature tolerance (−58 °C) as compared to that
derived from lower alcohol such as methyl alcohol (−42 °C). 相似文献
15.
Amalia A. Carelli Erica B. Bäumler Liliana N. Ceci 《European Journal of Lipid Science and Technology》2012,114(11):1312-1319
In this work, a modified International Olive Council (IOC) method for wax determination involving a double‐adsorbent layer of silica gel and silver nitrate‐impregnated silica gel is presented (SN method). Column chromatography by the SN method did not show retention of wax esters standards with an even number of carbon atoms (C34–C44), observing recovery percentages higher than 90% even for unsaturated wax esters. All wax fractions were lower by the SN method than by the IOC method, resulting in a percentage decrease in the total wax content (olive oils: 20–50%, crude sunflower oil: 38%, crude soybean oil: 58% and crude grape seed oil: 13%). Olive oils analysed by the SN method showed increases of up to 27% in C40 relative percentage with respect to the IOC method. Additionally, decreases were observed by the SN method in the relative percentages for odd‐carbon atom waxes for the seed oils in comparison to the IOC method (crude sunflower oil: 27%, crude soybean oil: 28% and crude grape seed oil: 13%). The main advantages of the proposed modification consist in its easy implementation and a better determination of wax esters (C34–C60) by controlling their complete recovery and removing interfering substances. The method is suitable for quality control and for authentication of olive oil and seed oils as well as in processing monitoring. Practical applications: The proposed method is useful in the quality, authentication and processing control of fruit and seed oils. Moreover, it can be an important tool for vegetable oil industries to control the efficiency of the wax separation process to prevent turbidity in the refined oil. 相似文献
16.
Palm oil contains high concentrations of carotenoids and tocopherols that can be recovered by first converting them to methyl
esters and then applying membrane technology to separate the carotenoids from the methyl esters. Several solvent-stable nanofiltration
membranes were investigated for this application. Flux with a model red palm methyl ester solution ranged from 0.5 to 10 Lm−2h−1, and rejection of β-carotene was 60–80% at a transmembrane pressure of 2.76 MPa and 40°C. A multistage membrane process was
designed for continuous production of palm carotene concentrate and decolorized methyl esters. With a feed rate of 10 tons
per hour of red palm methyl esters containing 0.5 gL−1 β-carotene, the process could produce 3611 L·h−1 of carotene concentrate containing 1.19 gL−1 carotene and 7500 Lh−1 of decolorized methyl esters containing less than 0.1 gL−1 β-carotene. The economics of this process is promising. 相似文献
17.
L. J. Malcolmson M. Vaisey-Genser R. Przybylski N. A. M. Eskin 《Journal of the American Oil Chemists' Society》1994,71(4):435-440
Sensory studies on autoxidation of canola oil, stored under several variations of Schaal Oven test conditions, suggest an
induction period of 2–4 d at 60–65°C. Similar induction periods have been observed between canola and sunflower oils, whereas
a longer induction period has been found for soybean oil. Canola oil seems to be more stable to storage in light than cottonseed
and soybean oils but is less stable than sunflower oil. Storage stability of products fried in canola oil is similar to products
fried in soybean oil. Storage stability of canola and cottonseed oils that had been used in the frying of potato chips showed
that canola oil was more prone to autoxidation during storage at 40°C. The presence of light aggravated the oxidative effects
and was similar for both oils. Advances in our knowledge about the shelf life of canola oil would be strengthened by standardization
of Schaal Oven testing conditions and by specifying the testing protocol for photooxidation studies. Methods for training
of panelists and for handling and evaluating oils and fried foods require definition. Rating scales used in the evaluation
of oils need to be evaluated to ensure that reliable and valid measurements are achieved. Further progress is needed in the
identification of chemical indicators that can be used to predict sensory quality of oils.
Presented in part at AOCS Annual Meeting in Toronto, Ontario, Canada, May 1992. 相似文献
18.
Two simple methods for determining total oil equivalent in cottonseed meal are described. The meal is extracted with methanol,
and the crude extract is either (a) saponified and subsequently acidified to find the weight of acids set free, or (b) subjected
to methanolysis to determine the weight of esters formed. When applied to a meal previously extracted with petroleum ether,
these methods determine lipids. Results obtained on three commercial cottonseed meals were in excellent agreement with those
obtained by the more cumbersome method requiring direct saponification of the ground meal. The methods described should also
be applicable to soybean and sunflower seed meals and to other systems containing lipids, such as flours, doughs, and leaf
proteins. One of the methods is particularly useful as a preliminary step in the determination of cyclopropenoid acids in
cottonseed meal because much larger lated as methyl esters. 相似文献
19.
C. G. Sidwell Harold Salwin Milada Benca J. H. Mitchell Jr. 《Journal of the American Oil Chemists' Society》1954,31(12):603-606
Summary An evaluation of thiobarbituric acid (TBA) as an agent for the measurement of fat oxidation was made by the application of
several empirical procedures to animal and vegetable fats. An extraction procedure was used for removing the products of oxidation.
The reaction with TBA was conducted in a boiling water bath to produce a red color, which was then estimated spectrophotometrically.
Fats stored at −20, 0, 72, and 100°F. (−29, −18, 22, and 38°C.) and fats oxidized by the active oxygen method (A.O.M.) and
by ultraviolet irradiation were examined. It was found that the TBA test might be of value in following the course of oxidation
of cottonseed oil and soybean oil in the A.O.M. apparatus. Higher TBA values were obtained for soybean oil than cottonseed
oil at comparable peroxide values. This is of interest because of the greater tendency of soybean oil to develop oxidized
flavors. The volatile reaction products of oxidation were collected in toluene, and a comparison of the TBA values at comparable
peroxide values of lard, cottonseed and soybean oils showed that the soybean oil volatiles developed the greatest intensity
of color.
Presented at the 27th Fall Meeting of the American Oil Chemists’ Society, Chicago, Ill., Nov. 2–5, 1953.
This paper represents research undertaken by the Quartermaster Food and Container Institute for the Armed Forces and has been
assigned No. 450 in the series of papers approved for application. The views and conclusions contained in this paper are those
of the authors. They are not to be construed as necessarily reflecting the views or indorsement of the Department of Defense. 相似文献
20.
Variables affecting the yields of fatty esters from transesterified vegetable oils 总被引:47,自引:25,他引:47
B. Freedman E. H. Pryde T. L. Mounts 《Journal of the American Oil Chemists' Society》1984,61(10):1638-1643
Transesterification reaction variables that affect yield and purity of the product esters from cottonseed, peanut, soybean
and sunflower oils include molar ratio of alcohol to vegetable oil, type of catalyst (alkaline vs acidic), temperature and
degree of refinement of the vegetable oil. With alkaline catalysts (either sodium hydroxide or methoxide), temperatures of
60 C or higher, molar ratios of at least 6 to 1 and with fully refined oils, conversion to methyl, ethyl and butyl esters
was essentially complete in 1 hr. At moderate temperatures (32 C), vegetable oils were 99% transesterified in ca. 4 hr with
an alkaline catalyst. Transesterification by acid catalysis was much slower than by alkali catalysis. Although the crude oils
could be transesterified, ester yields were reduced because of gums and extraneous material present in the crude oils.
Presented at the American Oil Chemists’ Society annual meeting, Chicago, May 1983. 相似文献