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1.
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
2.
Gülgün Yildiz Randy L. Wehling Susan L. Cuppett 《Journal of the American Oil Chemists' Society》2002,79(11):1085-1089
NIR spectroscopy was used successfully in our laboratory to monitor oxidation levels in vegetable oils. Calibration models
were developed to measure PV in both soy and corn oils, using partial least squares (PLS) regression and forward stepwise
multiple linear regression, from NIR transmission spectra. PV can be measured successfully in both corn and soy oils using
a single calibration. The most successful calibration was based on PLS regression of first derivative spectra. When this calibration
was applied to validation sample sets containing equal numbers of corn and soy oil samples, with PV ranging from 0 to 20 meq/kg,
a correlation coefficient of 0.99 between titration and NIR values was obtained, with a standard error of prediction equal
to 0.72 meq/kg. For both types of oil, changes occurred in the 2068 nm region of the NIR spectra as oxidation levels increased.
These changes appear to be associated with the formation of hydroperoxides during oxidation of the oils. 相似文献
3.
Christina Bauer-Plank Lisette Steenhorst-Slikkerveer 《Journal of the American Oil Chemists' Society》2000,77(5):477-482
Triacylglyceride hydroperoxides (HPO-TAG), the primary autoxidation products of triacylglycerides (TAG), have been analyzed
in polyunsaturated vegetable oils by means of nonaqueous reversed-phase high-performance liquid chromatography (HPLC) with
ultraviolet detection. Using a retention time model based on equivalent carbon numbers, mono- and bishydroperoxy TAG and hydroxy
TAG could be identified. The correlation between the peroxide value (POV) determined by iodometric titration and quantitative
HPLC results for HPO-TAG was established for sunflower oil samples with POV between 0.5 and 50 meq/kg. The recovery of HPO-TAG
in the HPLC procedure was found to be close to 100% in the POV range of 4 to 71 meq/kg. Absolute quantitative results for
HPO-TAG in sunflower oil samples could not be obtained accurately, as molar extinction coefficients of HPO-TAG occurring in
natural oils deviate from those of available HPO-TAG reference compounds. 相似文献
4.
Previous work in our laboratory demonstrated that soybean oil oxidation, expressed as PV, can be determined using NIR transmission
spectroscopy as an alternative to the official AOCS iodometric titration method. In the present study, a comparison of four
peroxide analytical methods was conducted using oxidized soybean oil. The methods included the official AOCS iodometric titration,
the newly developed NIR method, the PeroxySafe™ kit, and a ferrous xylenol orange (FOX) method, the latter two being colorimetric methods based on oxidation of iron. Five
different commercially available soybean oils were exposed to fluorescent light to obtain PV levels of 0–20 meq/kg; periodic
sampling was done to ensure having representative samples throughout the designated range. A total of 46 oil samples were
analyzed. Statistical analysis of the data showed that the correlation coefficient (r) and standard deviation of differences (SDD) between the standard titration and NIR methods were r=0.991, SDD=0.72 meq/kg; between titration and the PeroxySafe™ kit were r=0.993, SDD=0.56 meq/kg; and between the standard titration and FOX method were r=0.975, SDD=2.3 meq/kg. The high correlations between the titration, NIR, and PeroxySafe™ kit data indicated that these methods were equivalent. 相似文献
5.
Abderrahmane Aït Kaddour Evane Grand Nathalie Barouh Bruno Bara Pierre Villeneuve Bernard Cuq 《European Journal of Lipid Science and Technology》2006,108(12):1037-1046
The present study was aimed at determining the ability of near‐infrared (NIR) spectroscopy to in situ describe fat oxidation kinetics in three different cereal‐based products: salted crackers (20% saturated palm oil and lauric oil, sprayed on surface); healthy crackers (10% unsaturated rapeseed oil, homogeneously distributed inside the product matrix); and moist pasteurised Asian noodles (1.5% unsaturated rapeseed oil, sprayed on surface). Products were stored under accelerated oxidation conditions at 40 °C. Lipid oxidation rates were determined from peroxide value (PV) measurements. We observed no significant changes in PV for the dry crackers (3 meq/kg after 60 days), a slight linear increase in PV for the healthy crackers (40 meq/kg after 60 days), and a rapid increase for the Asian noodles (80 meq/kg after 20 days). The NIR spectra were recorded between 1000 and 2500 nm by using a Fourier Transform NIR spectrometer, using an external probe. Measurements were done directly in situ on the product, on the ground samples, and on the extracted fat phase. The analysis of NIR spectral data by PLS statistical methods demonstrated some correlation trends (R2 = 0.575–0.897; RMSEC = 17–55%) for the products having a significant increase in PV. It was not possible to propose predictive models to calculate the oxidation rate. 相似文献
6.
The hydroperoxides and secondary products formed from trilinoleoylglycerol autoxidized at 40°C were isolated and characterized
to clarify their contribution to oxidative deterioration of vegetable oils. The products were purified by high performance
liquid chromatography (HPLC) and identified, as intact triacylglycerols, by ultraviolet, infrared,1H NMR and13C NMR analyses, and after derivatization by lipolysis, gas chromatography, and gas chromatography-mass spectrometry. The main,
primary products included mono-,bis- and tris-9-hydroperoxy-trans-10,cit-12-; 9-hydroperoxy-trans-10,trans-12; 13-hydroperoxy-cis-9,trans-11; and 13-hydroperoxy-trans-9,trans-11-linolenoyl glycerols. The structures of the minor secondary products analyzed after derivatization were consistent with
known oxidative degradation products of linoleate hydroperoxides. HPLC analyses showed that thebis- and tris-hydroperoxides were formed from the mono-hydroperoxides during autoxidation at peroxide values above 18 and 28
meq/kg. Studies on the further oxidation of the mono-hydroperoxides support a mechanism for the consucutive formation ofbis- and tris-hydroperoxides from the monohydroperoxides. HPLC analyses showed that no preferential oxidation occurred between
the 1(3)- and 2-triglyceride positions. Hydroperoxides of linoleate triacylglycerols may be important precursors of volatile
compounds contributing to off-flavors of vegetable oils.
Presented at the 79th Annual American Oil Chemists' Society Meeting, Phoenix, Arizona, May 8–12, 1988. 相似文献
7.
Encapsulation of CO2-extracted sea buckthorn kernel oil and the stability of the products were investigated. Maltodextrin and an emulsifying starch
derivative were used for encapsulation by spray drying. Both shell materials significantly increased the storage stability
of sea buckthorn kernel oil, even though in maltodextrin capsules 10% of the total oil was extractable from the surface of
the capsule. The cornstarch sodiium octenyl succinate derivative capsules contained essentially no surface oil. After 9 wk
storage at controlled conditions (20°C, RH 50%), PV of the unencapsulated oil was above 90 meq/kg, whereas in the encapsulated
oils, the PV was still around 20 meq/kg. The PV of the encapsulated oil was dependent on the storage conditions. A small increase
in temperature (from 20 to 25–30°C) and a significant increase in humidity (from RH 50 to RH 50–70%) decreased the stability
of capsules. This was associated with the physical state of the microcapsule matrix and may be linked with glass transition
of the wall polymers. 相似文献
8.
Elina Hafer Ulrike Holzgrabe Sascha Wiedemann Kristie M. Adams Bernd Diehl 《European Journal of Lipid Science and Technology》2020,122(5)
Hydroperoxides are formed as the primary product during lipid oxidation, being analyzed as the peroxide value to detect the degradation level of oils and fats. As an alternative to the classical titration method according to Wheeler, a 1H‐{31P} decoupled NMR method is developed using triphenylphosphine (TPP) as a tagging agent. TPP reacts with peroxides to form TPP oxides. The quantification of the peroxide value is performed by comparing the amount of reacted TPP oxide and non‐reacted TPP. This approach eliminates the requirement for an additional internal standard. Low‐oxidized oils (peroxide value < 3 meq/kg) and high‐oxidized oils with peroxide values of 150 meq/kg are precisely quantified with an relative standard deviation (RSD) of 4.90% and 0.16%, respectively. A total number of 108 oil samples are examined using the newly‐developed 1H‐{31P} decoupled NMR method, indicating the applicability for vegetable oils and krill oils. Practical Applications: The developed NMR method is applicable for the determination of the peroxide value in vegetable, marine and krill oils presenting a powerful alternative for the Wheeler titration method. 相似文献
9.
Mette B. Let Charlotte Jacobsen Edwin N. Frankel Anne S. Meyer 《European Journal of Lipid Science and Technology》2003,105(9):518-528
The oxidative deterioration of milk emulsions supplemented with 1.5 wt‐% fish oil was investigated by sensory evaluation and by determining the peroxide value and volatile oxidation products after cold storage. Two types of milk emulsions were produced, one with a highly unsaturated tuna oil (38 wt‐% of n‐3 fatty acids) and one with cod liver oil (26 wt‐% of n‐3 fatty acids). The effect of added calcium disodium ethylenediaminetetraacetate (EDTA) on oxidation was also investigated. Emulsions based on cod liver oil with a slightly elevated peroxide value (1.5 meq/kg) oxidised significantly faster than the tuna oil emulsions, having a lower initial peroxide value (0.1 meq/kg). In the tuna oil emulsions the fishy off‐flavour could not be detected throughout the storage period. Addition of 5—50 ppm EDTA significantly reduced the development of volatile oxidation products in the cod liver oil emulsions, indicating that metal chelation with EDTA could inhibit the decomposition of lipid hydroperoxides in these emulsions. This study showed that an oxidatively stable milk emulsion containing highly polyunsaturated tuna fish oil could be prepared without significant fishy off‐flavour development upon storage, provided that the initial peroxide value was sufficiently low. 相似文献
10.
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
11.
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
12.
Ibrahim Nor Hayati Yaakob Bin Che Man Chin Ping Tan Idris Nor Aini 《European Journal of Lipid Science and Technology》2005,107(12):886-895
Soybean oil (SBO) was blended with 10–40% palm kernel olein (PKO) to obtain SBO:PKO blends with different degrees of unsaturation. Oil‐in‐water (O/W) emulsions were then prepared with 70 wt‐% of SBO or SBO:PKO blends and monitored for their chemical destabilization after an accelerated oxidation process up to 12 days at 60 °C. The formation rate of hydroperoxides, as demonstrated by peroxide value (PV) evolution, throughout the oxidation period was relatively high for a fully SBO‐based emulsion as compared to those with PKO incorporation. Fourier transform infrared (FTIR) spectroscopic method was also performed in parallel with PV determination, providing further information on structural changes of the functional groups due to lipid oxidation in the emulsions. By using a partial least square chemometric method, a developed calibration model that was based on the spectral region between 1800 and 1480 cm?1 was shown to be able to predict the PV in oxidized emulsions over the range of 4–45 meq/kg. With a ‘leave‐one‐out’ cross‐validation optimization procedure, the calibration model provides a good coefficient of determination of 0.98 and a root mean standard error of cross‐validation of 2.09. In general, FTIR spectroscopy is a suitable technique to monitor PV in oxidized emulsions. 相似文献
13.
Disposable polytetrafluoroethylene (PTFE) polymer IR (PIR) cards were used as substrates to rapidly oxidize edible oils and
simultaneously monitor the extent of oxidation by FTIR spectroscopy. Four edible oils were oxidized on PIR cards and in bulk
at moderate temperature (58°C), and real-time oxidation plots were obtained by measuring changes in the IR hydroperoxide (ROOH)
absorbance as a function of time. The relationship between the ROOH absorbance and PV was developed using a reference method
to define absorbances corresponding to PV end points of 100 and 200 meq ROOH/kg for the oils oxidized in bulk and on cards,
respectively. The real-time oxidation plots obtained for the oils oxidized in bulk and on cards were similar in appearance,
but the oils on the cards reached the PV end point 20 times faster than the oils oxidized in bulk. The results indicate that
the use of disposable PIR cards coupled with moderate heating and aeration provides a simple, practical, and rapid means for
monitoring oxidation and determining the oxidative stability of edible oils at a normal storage temperature. 相似文献
14.
A Comparative Study of the Properties of Selected Melon Seed Oils as Potential Candidates for Development into Commercial Edible Vegetable Oils 总被引:1,自引:0,他引:1
M. B. Mabaleha Y. C. Mitei S. O. Yeboah 《Journal of the American Oil Chemists' Society》2007,84(1):31-36
A comprehensive compositional and characterization study was carried out on five seed oils from varieties of the melons Citrullus lanatus and C. colocynth in order to evaluate their suitability for large-scale exploitation as edible vegetable oils. The oils were extracted by
Soxhlet with a 3:1 mixture of n-hexane/2-propanol with yields that ranged from 24.8 to 30.0% (wt/wt). The refractive indices and relative densities of the
oils fell within the narrow ranges of 1.465–1.469 and 0.874–0.954 g/cm3, respectively. Saponification values ranged between 182.1 and 193.8 mg KOH/g, whilst iodine values (IV) ranged from 95.8
to 124.0 (Wijs). The ranges of the values for free fatty acid (AV), 1.2–4.0 mg KOH/g, peroxide (PV), 1.1–10.9 meq/kg and p-anisidine (p-AV), 0.2–9.0, indicated that secondary oxidation products were barely present. GC analysis gave total unsaturation contents
of 67.93–82.36%, with linoleic acid (18:2) being the dominant fatty acid (55.21–66.85%). The GC results agreed closely with
those from proton NMR analysis of the fatty acid classes. The physicochemical and compositional properties determined in this
study show that the qualities of the test Cucurbitacea seed oils are highly comparable to those of soybean, sunflower and
groundnut seed oils. Therefore, the test melon seed oils could be developed into commercial products to serve as alternate
vegetable oils in Southern and West Africa, the regions where these melons grow. 相似文献
15.
P. M. Shiela Y. N. Sreerama A. G. Gopala Krishna 《Journal of the American Oil Chemists' Society》2004,81(12):1125-1129
The physicochemical characteristics and minor component contents of blended oils packed in pouches in relation to starting
oils used for blending were studied over a period of 6 mon at two storage temperatures and humidity conditions: 27°C/65% RH
and 40°C/30–40% RH. Color, PV, FFA value, β-carotene content, tocopherol content, and oryzanol content of the oils were monitored
at regular intervals. The color, PV (0.6–20.7 meq O2/kg, FFA value (0.08–2.1%), tocopherol content (360–1700 ppm%), oryzanol content (460–2,000 mg%), and sesame oil antioxidants
(400–2,000 mg%) were not changed in either the starting oils or their blends. Oils and oil blends containing a higher initial
PV (18.9–20.7 meq O2/kg) showed a slight reduction in value at 40°C, whereas oils having lesser PV of 5–10 showed a slight increase during the
storage period. Among the minor components studied, only β-carotene showed a reduction, 8.9–60.2% at 27°C and 48–71% at 40°C,
for the different oil blends studied. The observed results indicated that the packed oil blends studied were stable under
the conditions of the study, and the minor components, other than β-carotene, remained unaltered in the package even at the
end of 6 mon of storage. 相似文献
16.
Kangming Ma F. R. van de Voort A. A. Ismail Hualong Zhuo Binjing Cheng 《Journal of the American Oil Chemists' Society》2000,77(6):681-685
A Fourier transform infrared (FTIR) spectrometer equipped with an attenuated total reflectance (ATR) sample handling accessory
was used to rapidly monitor the peroxide value (PV) of oils undergoing catalytic oxidation to produce sulfonated fatliquors
used in the leather industry. PV quantitation was based on the stoichiometric reaction of triphenylphosphosphine (TPP) with
hydroperoxides to produce triphenylphosphine oxide (TPPO). By using a germanium ATR accessory that has a very short effective
pathlength, the spectral contributions of the base oil could be subtracted out, eliminating any oil-dependent intereferences
as well as providing a facile means of observing the spectral changes associated with the TPP/TPPO reaction. A calibration
was devised by adding a constant amount of TPP-saturated chloroform to oils containing varying amounts of tert-butyl hydroperoxide (TBHP) to produce TPPO that had a measurable band at 1118 cm−1. this band was linearly related to TBHP concentration and the calibration devised had an SD of ∼3.4 PV over the range of
0–250 PV. The ATR-PV method was standardized and the spectrometer programmed using Visual Basic to automate the analysis.
the automated FTIR-ATR method was found to be a convenient means of tracking PV of oils undergoing oxidation, and the results
correlated well with the PV values obtained using the AOAC iodometric method (r=0.94). The FTIR-ATR PV methodology provides a simple means of monitoring the PV of oils undergoing rapid oxidation and could serve
as a quality-control tool in the production of sulfonated oils for the leather industry. 相似文献
17.
Effect of natural antioxidants in virgin olive oil on oxidative stability of refined,bleached, and deodorized olive oil 总被引:1,自引:0,他引:1
M. Teresa Satue Shu-Wen Huang Edwin N. Frankel 《Journal of the American Oil Chemists' Society》1995,72(10):1131-1137
The factors influencing the oxidative stability of different commercial olive oils were evaluated. Comparisons were made of
(i) the oxidative stability of commercial olive oils with that of a refined, bleached, and deodorized (RBD) olive oil, and
(ii) the antioxidant activity of a mixture of phenolic compounds extracted from virgin olive oil with that of pure compounds
andα-tocopherol added to RBD olive oil. The progress of oxidation at 60°C was followed by measuring both the formation (peroxide
value, PV) and the decomposition (hexanal and volatiles) of hydroperoxides. The trends in antioxidant activity were different
according to whether PV or hexanal were measured. Although the virgin olive oils contained higher levels of phenolic compounds
than did the refined and RBD oils, their oxidative stability was significantly decreased by their high initial PV. Phenolic
compounds extracted from virgin olive oils increased the oxidative stability of RBD olive oil. On the basis of PV, the phenol
extract had the best antioxidant activity at 50 ppm, as gallic acid equivalents, but on the basis of hexanal formation, better
antioxidant activity was observed at 100 and 200 ppm.α-Tocopherol behaved as a prooxidant at high concentrations (>250 ppm) on the basis of PV, but was more effective than the
other antioxidants in inhibiting hexanal formation in RBD olive oil.o-Diphenols (caffeic acid) and, to a lesser extent, substitutedo-diphenols (ferulic and vanillic acids), showed better antioxidant activity than monophenols (p- ando-coumaric), based on both PV and hexanal formation. This study emphasizes the need to measure at least two oxidation parameters
to better evaluate antioxidants and the oxidative stability of olive oils. The antioxidant effectiveness of phenolic compounds
in virgin olive oils can be significantly diminished in oils if their initial PV are too high. 相似文献
18.
A new method for free fatty acid reduction in frying oil using silicate films produced from rice hull ash 总被引:4,自引:0,他引:4
Sodium silicate films were produced from rice hull ash silica, and their application in reducing free fatty acid (FFA) in
frying oil was investigated. Sodium hydroxide concentration of these films was 32, 28, 24, and 20% with silica concentration
of 45, 50, 55, and 60%, respectively. Moisture contents of these films were 20–23%. Adsorption performance of the films was
investigated in frying oil at 80°C for 10–40 min. FFA content gradually decreased with treatment time for all films. There
were no significant differences in FFA content among films for treatments up to 30 min. Treatment with 45 and 50% silica films
for 40 min led to significantly larger reduction in FFA compared to treatment with 60% silica film. Differences between the
FFA content of oil treated for 40 min with 55% silica and the FFA content of oils treated with other silica films were insignificant.
FFA content of oil decreased from 0.8 to 0.55, 0.55, 0.57, and 0.59% after 40 min treatment with 45, 50, 55, and 60% silica
film, respectively. Peroxide values (PV) of treated oils slightly increased from 48 to about 60 meq/kg for films with 45,
50, and 55% silica. Treatment with 60% silica led to a decrease in PV values to 42 meq/kg. Soap content of oil increased from
51 to over 100 ppm as a result of silicate film treatment. 相似文献
19.
In this study, the effect of deep fat frying on oil degradation, total phenols (TP) and total antioxidant activity (TAA) of
hazelnut, corn, soybean and olive oils were investigated. Oil degradation and oxidation were monitored by measuring the total
polar compounds (TPC) and the peroxide value (PV). The amount of TPC in corn, soybean and olive oils increased significantly
with the time increment (p < 0.05). The PV of the oils did not exceed the maximum acceptable limit of 10 mequiv O2/kg after 125 min frying except for hazelnut oil (10.64 mequiv O2/kg). Deep-fat frying did not cause any significant change in the TP of corn oil, soybean oil and olive oil (p < 0.05). A significant decrease in the antioxidant activity was observed after 50 min frying using hazelnut oil and corn
oil (p < 0.05). However, the antioxidant activity of soybean oil and olive oil significantly decreased after 75 and 25 min frying,
respectively. 相似文献
20.
W. E. Neff T. L. Mounts W. M. Rinsch H. Konishi 《Journal of the American Oil Chemists' Society》1993,70(2):163-168
The photooxidation of soybean oil was determined and correlated with triacylglycerol composition and structure. Purified triacylglycerols
were photooxidized at room temperature under fluorescent light. Rates of peroxide formation and total headspace volatiles
were related positively (P<0.5 significance) to oxidizability (r=0.75, r=0.76); content of linolenic acid (r=0.80, r=0.85) and linoleic acid (r=0.61,
r=0.57); linoleic acid on carbon 2 (r=0.64, r=0.64); and average number of double bonds (r=0.76, r=0.76). Negative correlations
were observed with respect to oleic acid (r=−0.70, r=−0.70). Soybean oil stability was decreased by linolenic acid-containing
triacylglycerols and increased by oleic acid-containing triacylglycerols. Trilinoleoylglycerol and dilinoleoyl-oleoylglycerol
were the most important oxidation product precursors. However, for high-linolenic acid soybean oil, dilinoleoyl-linolenoylglycerol
and trilinoleoylglycerol were the most important oxidation product precursors. The most abundant volatile produced from thermal
decomposition at 140°C of photooxidized triacylglycerols was 2-heptenal, except for high-linolenic acid oils, where the most
abundant volatile was propanal. The photooxidative stability of soybean oil triacylglycerols with respect to composition and
structure is of interest for the development of soybean varieties with oils of improved odor and flavor stability.
Presented at the 20th ISF World Congress 83rd Annual American Oil Chemists’ Society Meeting, May 10–14, 1992, Toronto, Canada. 相似文献