共查询到20条相似文献,搜索用时 31 毫秒
1.
Determination of Mineral Oil-Saturated Hydrocarbons (MOSH) in Vegetable Oils by Large Scale Off-Line SPE Combined with GC-FID
下载免费PDF全文
![点击此处可从《Journal of the American Oil Chemists](/ch/ext_images/free.gif)
Bingning Li Yanwen Wu Lingling Liu Jie Ouyang Jiajia Ren Yu Wang Xinxin Wang 《Journal of the American Oil Chemists' Society》2017,94(2):215-223
A method based on an off-line large-scale solid phase extraction (SPE) approach combined with conventional gas chromatographic-flame ionization detection (GC-FID) was developed to determine the mineral oil-saturated hydrocarbons (MOSH) in vegetable oils. A large-scale SPE column loaded with 10 g of activated silica gel impregnated with 1% silver nitrate which was used to retain lipids and olefins in vegetable oils and the MOSH in the oil samples was eluted with hexane. Then 2 μL concentrated solution was splitlessly injected into a common GC-FID instrument. The quantification limit reached 2.5 mg/kg when the MOSH fraction was concentrated to 0.1 mL. The accuracy of this procedure, as assessed by measuring the recoveries from spiked oil samples, was higher than 80%. This procedure was applied to analyze the MOSH in 38 commercial vegetable oils from Chinese market, which was the first survey of mineral oil contaminant in Chinese edible oils. The oil samples contaminated with different levels of MOSH, among which, 15 samples contained no mineral oils and 3 samples were contaminated with more than 50 mg/kg of MOSH. The highest contamination level was found in one of rice oils, in which the concentration of MOSH was up to 713.36 mg/kg. Of the 9 types of oils analyzed, camellia oil contained MOSH ranging between 6.76 and 78.49 mg/kg, averaging 46.72 mg/kg, indicating a higher contamination level than other types of oils. The results suggested that it is necessary to routinely detect mineral oil contamination in vegetable oils for food safety. 相似文献
2.
Rocío Marfil Rafael Giménez Olga Martínez Paula R. Bouzas José A. Rufián‐Henares Marta Mesías Carmen Cabrera‐Vique 《European Journal of Lipid Science and Technology》2011,113(7):886-893
This study establishes data on polyphenols, tocopherols, and antioxidant capacity (AC) of virgin argan oil. A total of 22 samples from Morocco were analyzed. Total polyphenol content ranged between 6.07 and 152.04 mg GAE/kg. Total tocopherols varied between 427.0 and 654.0 mg/kg, being γ‐tocopherol the major fraction (84.68%); α‐, β‐, and δ‐tocopherols represent 7.75, 0.33, and 7.29%, respectively. No influence of oil extraction method on total tocopherols was observed. The AC of argan virgin oils determined by the ABTS method in n‐hexane oils dilution ranged between 14.16 and 28.02 mmol Trolox/kg, and by the ABTS, DPPH, and FRAP methods in methanolic oil extracts between 2.31–14.15, 0.19–0.87, and 0.62–2.32 mmol Trolox/kg, respectively. A high correlation was found between ABTS and DPPH methods applied to a methanolic oil extract. Virgin argan oil presents a higher polyphenol and tocopherol content, and total AC than other edible vegetable oils. 相似文献
3.
R. C. Wijesundera R. G. Ackman V. Abraham J. M. deMan 《Journal of the American Oil Chemists' Society》1988,65(9):1526-1530
A simple method for the determination of total sulfur content in vegetable and marine oils is described. The method involves
combustion of the oil sample in an oxygen bomb to convert all forms of sulfur to sulfate ions with subsequent determination
of the sulfate by ion chromatography and indirect ultraviolet detection. The ultraviolet system described is more sensitive
than conductivity detection and enables the method to be applied more widely.
Application of the method to a variety of vegetable and marine oils showed the general occurrence of sulfur in fats and oils,
albeit often at a low level. Among the samples examined, crude Canola oil had the highest sulfur content (25.0 mg/kg) followed
by the marine oils (5.8-15.2 mg/kg) and the non-Cruciferae vegetable oils (2.0-6.1 mg/kg).
To whom correspondence should be addressed. 相似文献
4.
H. P. Dupuy S. P. Fore E. T. Rayner 《Journal of the American Oil Chemists' Society》1975,52(4):118-120
A simple, direct, gas chromatographic technique is described for the quantitative determination of residual hexane in extracted vegetable oils. The method if rapid and sensitive to one ppm hexane. The inlet liner of a gas chromatograph was packed with 1 1/2 in. glass wool, and 25 mg oil was added onto it. The sample was capped with a small plug of glass wool, and the liner was inserted in the heated inlet of the gas chromatograph. Residual hexane rapidly eluted onto the Poropak P column by heat, and carrier gas was resolved in 20 min by temperature programing between 70–180 C. The method appears useful for monitoring continuous solvent removal processes. 相似文献
5.
O. Yu Berezin Ya I. Tur’yan L. Kogan I. Kuselman A. Shenhar 《Journal of the American Oil Chemists' Society》1997,74(10):1339-1341
A novel pH-metric method is described for the determination of acid values (AV) in vegetable oils without titration. The method
is based on a reagent containing triethanolamine, isopropanol, and water to which an oil sample is added before measuring
pH. Oil samples with AV in the range 0.006–0.107 mg KOH/g oil were prepared from commercial soybean oil by treatment with
a strong-base anion exchanger in OH− form and addition of oleic acid. Compared to the standard titrimetric method, significantly greater AV were obtained at less
then 0.02 mg KOH/g oil. This was due to the influence of triethanolamine hydrolysis on the acid-base equilibrium in the mixture
“oil-reagent.” Thus, the AV 0.02 mg KOH/g oil is accepted as the limit of quantitation. Because refined oils usually have
AV of 0.05 mg KOH/g oil or more, this method should be suitable for practical oil analyses. 相似文献
6.
Differentiation of Mechanically and Chemically Extracted Hazelnut Oils Based on their Sterol and Wax Profiles
下载免费PDF全文
![点击此处可从《Journal of the American Oil Chemists](/ch/ext_images/free.gif)
Cansu Ekin Gumus Asli Yorulmaz Aziz Tekin 《Journal of the American Oil Chemists' Society》2016,93(12):1625-1635
The sterol and wax content of solvent extracted (SEHO) and cold pressed hazelnut oils (CPHO) were compared. A total of 48 samples from 19 hazelnut varieties were collected for two successive crop years from four different geographical districts in Turkey. Hazelnuts were processed to oil with a laboratory scale press, than the remaining oil in cake was extracted with n‐hexane. CPHO and SEHO were evaluated for their wax, sterol and squalene contents. Results showed that sterol, squalene and wax contents of all individual cultivars were higher in SEHO than those of CPHO, indicating the higher solubility of these compounds in solvent. Total sterol contents ranged between 1088.56 (Kargalak)—1609.39 mg/kg (Mincane) for CPHO and 1590.86 (Çak?ldak)—2897.26 mg/kg (Mincane) for SEHO. Hazelnut oils were found to be richer of C36‐38 esters than C40‐46 group. Total wax content was between 24.19 (Kargalak)—94.58 mg/kg (Ku?) for CPHO and 81.46 (Kargalak)—160.92 mg/kg (Akçakoca) for SEHO. The squalene amounts of the samples obtained by hexane extraction were between 499.75 (Allahverdi)—885.36 mg/kg (Cavcava), while it varied between 288.55 (Kargalak)—647.68 mg/kg (Mincane) in cold pressed oils. Significant and obvious variations between SEHO and CPHO were verified by principal component and hierarchical cluster analysis. Geographical discrimination was also achieved by discriminant analysis. 相似文献
7.
8.
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
9.
Isabel M. G. Lopes M. Gabriela Bernardo‐Gil 《European Journal of Lipid Science and Technology》2005,107(1):12-19
Acorn fruit oils from two species of oak, Quercus rotundifolia L. (holm‐oak) and Quercus suber L. (cork‐oak), were extracted by n‐hexane. The acorn fruit of Quercus rotundifolia L. was also extracted by supercritical CO2 at 18 MPa and 313 K, a superficial velocity of 2.5 × 10?4 ms?1, and a particle size diameter of 2.7 × 10?4 m. The oils were characterised in terms of fatty acids, triglycerides, sterols, tocopherols, and phospholipids. The main fatty acid in both fruit species was oleic acid (about 65%), followed by linoleic acid (about 16.5–17%) and palmitic acid (about 12.1–13.4%). The main triglyceride found in acorn oils was the OOO (oleic, oleic, oleic) triglyceride (33–38%), followed by the POO (palmitic, oleic, oleic) triglyceride (12.6–18.2%). In terms of sterols, the main component in acorn oils of both species was β‐sitosterol (83.5–89%), followed by stigmasterol (about 3%). However, in Quercus suber L., acorn oil was found to consist to 10.2% of campesterol. The amount of cholesterol was low (0.27% for the Quercus rotundifolia L. oil extracted by supercritical fluid extraction, and 0.18% for the oil extracted by n‐hexane). The Quercus suber L. acorn oil presented 0.1% of cholesterol. The total amount of tocopherols in Quercus rotundifolia L. acorn oils was almost the same when the oil was extracted by n‐hexane (973 mg/kg oil) or by supercritical CO2 (1006 mg/kg oil). The Quercus suber L. acorn oil presented a high value of total tocopherols (1486 mg/kg oil). The supercritical CO2 did not extract the phospholipids. The amount of phospholipids was very similar for both species of oak acorn oils extracted by n‐hexane. Oxidative stability was also studied, by using the peroxide value and the Rancimat method, revealing that all the oils were significantly protected against oxidation. The influence of storage, under several conditions, on the oxidative stability was also studied. The Quercus rotundifolia L. oil extracted by n‐hexane was better protected against oxidation after a few days of storage at 60 °C. 相似文献
10.
Hexane is used to extract edible oils from oleaginous seeds. The detection of hexane in orujo oil is mandatory, as its presence
in the final product may negatively affect human health. Headspace-GC is the technique of choice for determining residual
solvent in foods. In the present work, a new instrument based on the headspace principle and mass spectrometric detection
without chromatographic separation, ChemSensor, is proposed for the direct screening of orujo oil to determine residual hexane.
This instrument provided an overall response, corresponding to the volatiles profile, including that of hexane, which could
not be directly discriminated. By selecting the m/z values corresponding to n-hexane (major component of commercial hexane), the selectivity of the method was good enough to determine residual hexane
in the range of 2.0–65 μg mL−1 (corresponding to 2.3–75.6 mg of hexane per kg of oil) with high precision. The detection limit achieved (0.7 mg per kg of
oil) was lower than the maximum residual limit established by the European Union (5 mg per kg of oil). Two multivariate techniques,
partial least squares and principal components regression (PCR), were compared with univariate regression; PCR provided the
best results. 相似文献
11.
Vilppu Kuuluvainen Päivi Mäki‐Arvela Kari Eränen Anton Holappa Jarl Hemming Heidi Österholm Blanka Toukoniitty Dmitry Y. Murzin 《化学工程与技术》2015,38(5):769-776
The extraction of oils based on animal fat and vegetable oil from two types of spent bleaching earths, namely from the acidic sepiolite and the nonacidic palygorskite, was investigated by the Soxhlet method with hexane as a solvent. The yields of oil were independent of the feedstock, whereas a much lower oil yield was obtained with palygorskite exhibiting also a smaller surface area as compared to sepiolite which provided a higher yield. The glyceride compositions were very similar in bleached and extracted oils, while slightly lower melting and crystallization energies were determined by differential scanning calorimetry for the extracted oils bleached with acidic clay indicating minor hydrolysis of triglycerides. 相似文献
12.
Nikolaos K. Andrikopoulos Antonia Chiou Anastasia Mylona George Boskou George V. Z. Dedoussis 《European Journal of Lipid Science and Technology》2004,106(10):671-679
Some frying by‐products of medium polarity, so‐called medium‐polarity materials (MPM), produced during domestic deep‐frying of French‐fried potatoes in edible vegetable oils, have recently been isolated and linearly correlated to % total polar materials and % polymerized triglycerides. The in vitro oxidation of low‐density lipoproteins in a dose‐dependent manner by MPM has also been reported. In the present study, the MPM constituents were identified after extraction of MPM from the oils, subsequent purification by RP‐HPLC, and GC‐MS analysis. The main constituent of MPM was trans,trans‐2,4‐decadienal, a compound that has previously been reported to be formed during peroxidation of linoleic and arachidonic acid. 2,4‐Decadienal was also quantified in oils and fats used for frying in restaurants in Athens, Greece, by direct injection of oil sample solutions in HPLC. For the most commonly used frying oils, 2,4‐decadienal concentration ranges were 0.3–119.7 mg/kg for sunflower oil, 13.3–92.7 mg/kg for cottonseed oil, 4.1–44.9 mg/kg for palm oil, and 2.0–11.3 mg/kg for vegetable cooking fats. Considering the common catering practices of frying, 2,4‐decadienal was more likely to be found in sunflower oil after deep‐frying of potatoes. Comparing the amounts of this aldehyde found in oils from restaurants to the amounts previously found for domestic frying (up to 30 mg/kg after the 8th successive frying session in sunflower oil), the probability of consuming a level of 2,4‐decadienal in restaurant‐prepared food that is higher than the level in home‐fried food was determined to be approximately one third. 相似文献
13.
A simple, direct gas Chromatographic (GC) tech-nique is described for the quantitative determination of residual hexane in
extracted vegetable oils. The method is rapid and sensitive to one ppm hexane. A platinum boat, on which sample oil was placed,
is inserted into a pyrolysis chamber in a pyrolyzer at-tached to a GC, and heated at 150 C for 60 sec to carry the evaporated
hexane into the GC with a carrier gas. In the method, the column of GC may be used without the possibility of contamination
because the sample is not injected directly into the GC. The method should be useful for the quality con-trol of solvent extracted
oil products. 相似文献
14.
Effect of Oils Extracted from Plant Seeds on the Growth and Lipolytic Activity of <Emphasis Type="Italic">Yarrowia lipolytica</Emphasis> Yeast
下载免费PDF全文
![点击此处可从《Journal of the American Oil Chemists](/ch/ext_images/free.gif)
This study was aimed at evaluating the capability of Yarrowia lipolytica W29 for the synthesis of lipolytic enzymes in a medium containing plant oils from non‐conventional sources with some components displaying bioactivity. Oils from almond, hazelnut, and coriander seeds were obtained by using n‐hexane (Soxhlet method) and a chloroform/methanol mixture of solvents (Folch method), and their effect on the growth and lipolytic activity of Y. lipolytica was compared. A comparison of these two extraction methods showed that the extraction with n‐hexane was less effective regarding the oil extraction yields than the extraction conducted according to Folch's procedure. The lipolytic activity of the studied yeast was higher in the culture media containing oils extracted with the Soxhlet method than the Folch method but it was lower compared to olive oil medium. Among all oils tested, almond oil extracted with n‐hexane was the best inducer of extracellular lipases synthesized by Y. lipolytica. Its lipolytic activity achieved the maximum value of 2.33 U/mL after 48 h of culture. After 24 h of culture, it was close to the value obtained for the medium containing olive oil. Almond oil was a source of oleic and linoleic acids, which may determine differences in the lipolytic activity. The linoleic acid content in almond oil was higher than that found in other oils. When n‐hexane was used for extraction, the resultant oils were characterized by lower contents of polyphenols and poorer antioxidative activity. 相似文献
15.
Rahul K. Lall Andrew Proctor Vishal P. Jain 《Journal of the American Oil Chemists' Society》2009,86(4):309-314
A 30-min, micro-base-catalyzed method for vegetable oil fatty acid methyl ester (FAME) preparation was developed using only
1 mg of oil sample by limiting the solvent volumes used. This method was primarily developed to quickly analyze fatty acid
composition of CLA-rich soy oil but can be further applicable to pure vegetable oils. Existing base-catalyzed FAME preparation
methods are not appropriate to use because they are either rapid but not micro, or micro but not rapid, or are rapid and micro
but use acidification in the final step of FAME preparation, which would isomerize oils containing conjugated fatty acids.
Serial dilutions of a mixed commercial FAME reference standard were prepared and analyzed by GC with a flame ionization detector
(FID) with maximum instrument sensitivity. The novel method was also used to prepare soy oil FAMEs for GC-FID analysis. There
were no statistically significant differences (P < 0.05) in fatty acid data from the FAME reference standard dilutions. Similarly, there was no statistical significant difference
(P < 0.05) between results obtained for all the soy oil dilutions and the control method. This technique is a rapid method for
preparing small pure oil samples as FAMEs for GC-FID analysis. 相似文献
16.
Aqueous Extended-Surfactant Based Method for Vegetable Oil Extraction: Proof of Concept 总被引:1,自引:0,他引:1
The use of hexane to extract vegetable oil from oilseeds is of growing concern due to hexane’s environmental impact and because
of worker exposure concerns. The goal of our work is to demonstrate that the aqueous extended-surfactant-based method is a
viable alternative for vegetable oil extraction. In our method, ground oilseeds were dispersed in the aqueous surfactant solution,
allowing the oil to be liberated from the seeds as a separate phase from the aqueous phase. The impact of pH, shaking intensity,
shaking time and seed to liquid ratio on oil yield are presented. Extended-surfactants are a new type of surfactant with propoxylate
(PO) and/or ethoxylate (EO) groups inserted between the hydrophilic head and the hydrophobic alkyl chain of the surfactant
molecule. This unique structure of extended-surfactants enables them to produce ultralow interfacial tension with vegetable
oils. We have found that at low aqueous concentrations (less than 0.3 wt%), extended-surfactant solutions are able to produce
ultralow interfacial tension between aqueous extraction and vegetable oil phases. At optimum condition (seed to liquid ratio
of 1–5, 30 min extraction at 150 shakes/min and 30 min centrifugation at 2,170×g) we achieved 93–95% extraction efficiency for peanut and canola oils at 25 °C. The oil quality produced from the aqueous
extended-surfactant-based method was found to be comparable or even superior to that obtained from hexane-based extraction,
further demonstrating the viability of aqueous extended-surfactant based extraction. 相似文献
17.
For several decades, scientists in the field of vegetable oils tried unsuccessfully to detoxify cottonseed by a practical
method. By using 20-30% (by wt) of ethyl alcohol (90% in vol) with commercial hexane as a mixed solvent, we were able to extract
effectively both gossypol and oil from cottonseed prepressed cake or flakes. Free gossypol in meal was reduced to ca. 0.013-0.04%;
total gossypol was reduced to 0.32-0.55%; residual oil was reduced to ca. 0.5% or less. Any aflatoxin present also can be
eliminated by this process. The detoxified cottonseed meal can be used as animal feed. Cottonseed protein can be used to substitute
for soy protein. The extracted oil is of better quality than that obtained by the usual hexane extraction method, and gossypol
is a valuable byproduct. 相似文献
18.
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
19.
A flow injection analysis (FIA) system coupled with a fluorescence detection system using diphenyl-1-pyrenylphosphine (DPPP)
was developed as a highly sensitive and reproducible quantitative method of total lipid hydroperoxide analysis. Fluorescence
analysis of DPPP oxide generated by the reaction of lipid hydroperoxides with DPPP enabled a quantitative determination of
the total amount of lipid hydroperoxides. Use of 1-myristoyl-2-(12-((7-nitro-2-1,3-benzoxadiazol-4-yl)amino) dodecanoyl)-sn-glycero-3-phosphocholine as the internal standard improved the sensitivity and reproducibility of the analysis. Several commercially
available edible oils, including soybean oil, rapeseed oil, olive oil, corn oil, canola oil, safflower oil, mixed vegetable
oils, cod liver oil, and sardine oil were analyzed by the FIA system for the quantitative determination of total lipid hydroperoxides.
The minimal amounts of sample oils required were 50 μg of soybean oil (PV=2.71 meq/kg) and 3 mg of sardine oil (PV=0.38 meq/kg)
for a single injection. Thus, sensitivity was sufficient for the detection of a small amount and/or low concentration of hydroperoxides
in common edible oils. The recovery of sample oils for the FIA system ranged between 87.2±2.6% and 102±5.1% when PV ranged
between 0.38 and 58.8 meq/kg. The CV in the analyses of soybean oil (PV=3.25 meq/kg), cod liver oil (PV=6.71 meq/kg), rapeseed
oil (PV=12.3 meq/kg), and sardine oil (PV=63.8 meq/kg) were 4.31, 5.66, 8.27, and 11.2%, respectively, demonstrating sufficient
reproducibility of the FIA system for the determination of lipid hydroperoxides. The squared correlation (r
2) between the FIA system and the official AOCS iodometric titration method in a linear regression analysis was estimated at
0.9976 within the range of 0.35−77.8 meq/kg of PV (n=42). Thus, the FIA system provided satisfactory detection limits, recovery, and reproducibility. The FIA system was further
applied to evaluate changes in the total amounts of lipid hydroperoxides in fish muscle stored on ice. 相似文献
20.
G. William Chase Jr. Casimir C. Akoh Ronald R. Eitenmiller 《Journal of the American Oil Chemists' Society》1994,71(8):877-880
A comparison of the responses of an evaporative light-scattering detector (ELSD) and a fluorescence detector for tocopherols
in vegetable oils by high-performance liquid chromatography is presented. The tocopherols were separated from acylglycerols
by gel-permeation chromatography (GPC). The tocopherol fraction was collected off a set of four GPC columns with a mobile
phase of methylene chloride before separation on a normal-phase silica column with a mobile phase of hexane/isopropanol, 99.7∶0.3
(vol/vol). An internal standard of 5,7 dimethyltocol, which was detected by both the ELSD and fluorescence detector, was used
to obtain quantitative data. The fluorescence detector was ten times more sensitive than the ELSD. γ-Tocopherol was the major
tocopherol detected in the vegetable oils studied and ranged from 24.1–93.3 mg/100 g. The amounts of tocopherols found in
the vegetable oils agreed favorably with the literature values. 相似文献