Mineral Oil Hydrocarbons (MOSH/MOAH) in Edible Oils and Possible Minimization by Deodorization Through the Example of Cocoa Butter

Mineral oil hydrocarbons (MOH) are present in many fats and oils as well as foods prepared thereof. A survey of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) in different types of vegetable fats and oils is reported. Contents of MOSH/MOAH were quantified using liquid chromatography online‐coupled to gas chromatography with flame‐ionization detection (LC‐GC‐FID). Cocoa butter (n = 142) showed levels from <LOQ (2.5 mg kg^?1) to 162 mg kg^?1 ΣMOSH (sum of C10–C50) and <LOQ to 55 mg kg^?1 ΣMOAH, in palm oil (n = 21) ΣMOSH were quantified from <LOQ to 124 mg kg^?1 and ΣMOAH from <LOQ to 39 mg kg^?1. Sunflower oil showed lower levels: ΣMOSH were determined in the range of <LOQ to 17 mg kg^?1 and MOAH were not observed at all. A possible influence of deodorization and a subsequent minimization of MOSH/MOAH was investigated. Systematic model‐experiments were performed on laboratory scale using spiked cocoa butter. Significant minimization of volatile MOH subfractions ≤C24 were observed at a deodorization temperature of 210 °C. Deodorization can be considered as an important processing step to reduce or even remove volatile MOSH/MOAH ≤C24. Practical Applications: Regardless of their possible entry routes into the food chain, volatile fractions of MOSH/MOAH can be removed by deodorizing vegetable fats and oils. This model‐study identifies the temperatures of deodorization that provide a significant improvement toward minimization of undesired MOSH/MOAH.     

Mineral saturated hydrocarbons and mineral aromatic hydrocarbons in tropical plant oils and their removal by molecular distillation

Nowadays, tropical plant oils (e.g., palm oil and coconut oil) are extensively used in consumer products, especially in infant formulas. However, there is a lack of statistical data on the levels of mineral oil in these oils, including mineral saturated hydrocarbons (MOSH) and mineral aromatic hydrocarbons (MOAH). In this study, we reported a survey of MOSH/MOAH in tropical oils, and in addition, we provided an effective strategy (i.e., molecular distillation) to reduce their contents. A total of 686 tropical plant oils were collected from five tropical countries for this survey. The highest quantifiable MOSH and MOAH concentrations were up to 456.0 and 78.9 mg kg⁻¹, respectively. Interestingly, MOSH was ubiquitous in almost all the tested samples. The distribution of sub-fractions for MOSH centered at C25–C35 and C35–C40 in most crude and refined oils. After distillation, the MOH sub-fraction ≤40 was effectively removed, but >40 was unaltered.     

Levels of 15 + 1 EU Priority Polycyclic Aromatic Hydrocarbons in Different Edible Oils Available in the Syrian Market

ABSTRACT

The levels of 15 + 1 EU priority polycyclic aromatic hydrocarbons (15 + 1 EU PAHs) have been determined in different edible oils (extra virgin olive oil, virgin olive oil, sunflower oil, corn oil, and soybean oil) available in the Syrian market. The samples have been prepared by donor–acceptor complex chromatography and subsequently characterized by high-pressure liquid chromatography coupled with fluorescence and ultraviolet detection for quantification purposes. Variable levels of contamination have been found within different kinds of edible oil samples, and only chrysene has been detected in all the studied samples. Moreover, the mean total sum of 15 + 1 EU PAHs has shown variation from 29.8 µg/kg (corn oil) to 63.7 µg/kg (virgin olive oil). A total of 11 samples out of 38 samples (28.9%) have not fulfilled the European Union (EU) food law requirements. Nine samples have exceeded the EU legislation limit of benzo[a]pyrene (BaP) (2 µg/kg) and only two samples have exceeded the EU legislation limit of PAH4 (10 µg/kg) and had acceptable level of BaP. Finally, the mean and maximum dietary exposures of PAHs through consumption of edible oils have been estimated.     

The determination of light petroleum residues in refined oils and fats

A rapid, direct injection gas liquid chromatographic (GLC) method for determining residual light petroleum in edible vegetable oils has been developed. The response is linear at levels between 0.05–0.5 mg hexane/kg oil. A sample containing 0.2 mg hexane/kg oil was analyzed for repeatability, giving a standard deviation of 0.008 mg/kg, equivalent to a coefficient of variation of 4%. Separation of pentane, hexane, heptane, octane and decane was obtained by this method. A survey of 23 samples of freshly refined vegetable oils obtained from 13 U.K. refiners in 1981 showed that these all contained less than 0.05 mg hexane/kg oil.     

Collaborative Study for the Analysis of Glycidyl Fatty Acid Esters in Edible Oils using LC–MS

An interlaboratory study was conducted to evaluate a method for determining glycidyl fatty acid esters (GE) in edible oils. Samples were dissolved in tert-butyl methyl ether/ethyl acetate and subjected to two solid-phase extraction (SPE) steps. The first SPE step utilized methanol elution from a C18 cartridge, and the second SPE step utilized n-hexane/ethyl acetate elution from a silica cartridge. The final extract was analyzed using liquid chromatography with a single quadrupole mass spectrometer in selected ion monitoring (SIM) mode. Quantification was performed using external standardization. Eighteen samples (9 oils × 2 blind duplicates) were assayed for glycidyl palmitate, glycidyl stearate, glycidyl oleate, glycidyl linoleate and glycidyl linolenate by 17 collaborating laboratories from seven countries. Sample matrices included palm, olive, corn, soybean and rapeseed oils. Repeatability (RSDr) ranged from 6.85 to 19.88 % and reproducibility (RSDR) ranged from 16.58 to 35.52 % for samples containing greater than 0.5 mg/kg of individual GE. HORRAT_R values ranged from 0.62 to 14.70 for determination of total GE. The method provides acceptable results for quantification of GE in edible oils.     

Detection of polycyclic aromatic hydrocarbons in commonly consumed edible oils and their likely intake in the Indian population

Edible oils such as coconut, groundnut, hydrogenated vegetable, linseed, mustard, olive, palm, refined vegetable, rice bran, safflower, sesame, soybean, and sunflower were analyzed for the presence of light and heavy polycyclic aromatic hydrocarbon (PAH) residues using liquid-liquid extraction, cleanup on a silica gel column, and resolution and determination by HPLC using a fluorescence detector. Ten PAH viz. acenaphthene, anthracene, benzo(a)pyrene, benzo(e)pyrene, benz(ghi)perylene, chrysene, coronene, cyclopenta(def)phenanthrene, phenanthrene, and pyrene were monitored. Analysis of 296 oil samples showed that 88.5% (262) samples were contaminated with different PAH. Of 262 contaminated edible oil samples, 66.4% of the samples showed PAH content of more than the 25 μg/kg recommended by the German Society for Fat Science. The total PAH content was highest in virgin olive oil (624 μg/kg) and lowest in refined vegetable oils (40.2 μg/kg). The maximum content (265 μg/kg) of heavy PAH was found in olive oil and the minimum (4.6 μg/kg) in rice bran oil. Phenanthrene was present in 58.3% of the oil samples analyzed, followed by anthracene (53%). Among the heavy PAH, benzo(e)pyrene was observed in 31.2% of the samples followed by benzo(a)pyrene (25.5%). The intake of PAH was highest through olive oil (20.8 μg/day) followed by soybean oil (5.0 μg/day) and lowest through refined vegetable oil (1.3 μg/day). Based on these monitoring studies, international and national guidelines for permissible levels of PAH can be prepared so as to restrict the intake of these toxic contaminants.     

Determination of sulfur contents of vegetable and marine oils by ion chromatography and indirect ultraviolet photometry of their combustion products

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.     

Adulteration and Presence of Polycyclic Aromatic Hydrocarbons in Extra Virgin Olive Oil Sold on the Brazilian Market

Seventy samples sold in the Brazilian market as extra virgin olive oil (EVOO) were evaluated for the presence of the 13 polycyclic aromatic hydrocarbons (PAH) classified as carcinogenic and genotoxic by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), to verify if the products were adulterated and to evaluate if there is a correlation between PAH presence and adulteration. PAH were detected in 93% of the samples, with summed levels varying from not detected to 41.10 μg/kg. Five samples showed BaP concentration above acceptable levels set by European legislation and by Brazilian regulation (2.0 μg/kg) and 7 presented PAH4 levels above the limit set by European legislation (10.0 µg/kg). The levels of fatty acid composition, sterols content, stigmastadiene and specific extinction did not comply with both Brazilian and International Olive Council (IOC) standards in 18, 31, 30 and 21% of the samples, respectively. The tolerance levels for these analyses in the Brazilian standards are 55.0–83.0 g/100 g (oleic acid), 3.5–21.0 g/100 g (linoleic acid), ≤0.05 g/100 g (trans-oleic acid), ≤0.05 g/100 g (trans-linoleic + trans-linolenic acid), ≤0.15 mg/kg (stigmastadiene), ≤2.50 (K232), ≤0.22 (K270), ≤0.01 (?K), 1000–1600 mg/kg (Σ sterols). Results indicate that 19 samples were adulterated. According to principal component analysis, samples were distinguished as: (1) EVOO with addition of vegetable oil from another source, (2) EVOO with addition of refined oil and (3) samples possibly not adulterated. The variable ΣPAH was related mainly to samples of EVOO with addition of vegetable oil from another source.     

Development of steryl ester analysis for the detection of admixtures of vegetable oils

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.     

A Rapid,Micro FAME Preparation Method for Vegetable Oil Fatty Acid Analysis by Gas Chromatography

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.     

Cultivar Characterization of Tea Seed Oils by Their Active Components and Antioxidant Capacity

Cultivar characterization of tea seed oils based on their active components and antioxidant capacity was carried out, providing fundamental data for authentication. The seeds were collected from 28 cultivars grown under the same conditions in the region of Anxi county of Fujian province and their oils were analyzed. The results showed that total phenols content (TPC), total flavonoids content, α-tocopherol contents, γ-tocopherol content and δ-tocopherol content were 16.7–529.3 mg GAE/kg of oil, 4.4–208.7 mg rutin/kg of oil, 7.7–347.1 mg/kg of oil, 1.8–106.7 mg/kg of oil, 0.003–35.769 mg/kg of oil, respectively. The antioxidant capacity measured by DPPH radical scavenging activity (DPPH), oxygen radical absorbance capacity (ORAC), absorbance of protein carbonyl (APC) and the absorbance of protein hydroperoxides (APH) were 91.0–2,164.5 μmol/100 g of oil, 251.0–1,209.5 μmol/100 g of oil, 0.014–0.135, 0.034–0.458, respectively. The correlation analysis revealed that the presence of phenolic compounds was significantly correlated with the antioxidant capacity of tea seed oil. Principal Component Analysis revealed the first three components accounted for 81.31 % of the total variance within the data and the main contributor parameters were DPPH, ORAC, APC, APH and TPC. Hierarchical cluster analysis classified the cultivars into three groups, which were in line with the genetic relationship among the cultivars. Our results supplied basic data for the antioxidant mechanism research of tea seed oil and provided necessary information to develop a breeding program directed to tea seed cultivar selections with the high nutraceutical value of tea seed oil.     

Monitoring of 2,4‐decadienal in oils and fats used for frying in restaurants in Athens,Greece

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 8^th 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.     

Physicochemical and Antioxidant Characteristics of Kapok (Ceiba pentandra Gaertn.) Seed Oil

In view of the growing demand for vegetable oils and fats, currently exploration of some under-utilized and non-conventional oil seed crops is of great concern. This work presents data on the detailed physicochemical and antioxidant attributes of kapok (Ceiba pentandra Gaertn.) seed oil. The kapok seeds contained an appreciable amount of oil (27.5 %), protein (35.0 %) and fiber (19.0 %). The extracted kapok seed oil (KSO) had an iodine value of 101.8 g of I₂/100 g of oil, a saponification value of 187 mg of KOH/g of oil), and unsaponifiable matter 0.83 %. KSO also showed a good oxidation state as indicated by the measurements of the peroxide value, conjugated dienes, conjugated trienes, para-anisidine and the induction period (Rancimat method). The tested oil showed a considerable amount of total phenolics (2.50 mg/100 g) and an appreciable free radical scavenging capacity. Gas liquid chromatographic analysis of fatty acids (FA) reveals that KSO mainly has linoleic acid (33.6 %) followed by oleic acid (23.4 %) and palmitic acid (22.4 %). Besides, a notable amount of cyclopropenoid fatty acids such as malvalic acid (9.1 %) and sterculic acid (2.8 %) was also detected. The FA composition of the tested oil was further verified by recording FTIR and NMR spectra. Among the oil phytosterols, analyzed by GC/GC–MS, β-sitosterol was found to be the principal component whereas RP-HPLC analysis showed the occurrence of γ-tocopherol (550 mg/kg) as the major tocopherol along with considerable amount of α-tocopherol (91 mg/kg) and δ-tocopherol (5.52 mg/kg). It can be concluded from the results of this comprehensive study that under-utilized kapok seeds are a potential feed stock for the production of a useful oil for edible and/or oleochemical applications.     

Antioxidant Activities and Oxidative Stabilities of Some Unconventional Oilseeds

The oils of some unconventional oilseeds (hemp, radish, terebinth, stinging nettle, laurel) were obtained by a cold-press method in which the total oil content, fatty acids, tocopherol isomers, some metal contents (Ca, Mg, Fe, Cu), antioxidant activity and oxidative stability were determined. The total oil content was determined ranging between 30.68 and 43.12%, and the oil samples had large amounts of unsaturated fatty acids, with oleic acid and linoleic acid. Of all the oils, terebinth seed oil had the highest α-tocopherol content (102.21 ± 1.01 mg/kg oil). Laurel oilseed had the highest antiradical activity in both the DPPH and ABTS assays. The peroxide value of the non-oxidized oils ranged between 0.51 and 3.73 mequiv O₂/kg oil. The TBARS value of the non-oxidized oils ranged between 0.68 ± 0.02 and 6.43 ± 0.48 mmol MA equiv/g oil. At 110 °C, the Rancimat induction period of the oils ranged between 1.32 and 43.44 h. The infrared spectra of the samples were recorded by FTIR spectroscopy. The absorbance values of the spectrum bands were observed and it was determined that some of the chemical groups of oxidized oils caused changes in absorbance. As a result of the present research, the analyzed oils could be evaluated as an alternative to traditionally consumed vegetable oils or as additives to them.     

Physicochemical Characteristics and Aflatoxin Levels in Two Types of Sudanese Sesame Oil

The physicochemical characteristics and aflatoxin levels of two types of sesame oil [Walad (W) and Normal (N)] were determined. A total of 104 sesame oil samples were collected during two seasons (I and II) from traditional mills in five states of Sudan. Levels of aflatoxin B₁, B₂, G₁, and G₂ were determined using HPLC. The physicochemical characteristics of W and N samples were significantly (P ≤ 0.05) different: samples of W and N from the five states had fluctuations in physicochemical characteristics in the two seasons. The highest percentage of contamination (recorded in Khartoum followed by Kordofan state) by aflatoxin B₁ during season II occurred in normal sesame oil which was 80.77 %, followed by Walad sesame oil which was 76.92 %. These percentages of contamination in season I were lower than 59.26 % for normal sesame oil and lower than 52.0 % for Walad sesame oil in season II. Aflatoxin B₂ contamination recorded the highest incidence in season II (3 out of 26 samples, 11.54 %) of normal sesame oil, followed by Walad sesame oil (2 out of 26 samples, 7.69 %). These percentages were lower than the 7.40 and 4.0 % of normal and Walad sesame oils in season I, respectively. Aflatoxin B₁ and B₂ levels in sesame oil ranged from 0.5 to 9.8 and 0.5 to 1.3 μg/kg, respectively.     

Proficiency test on the determination of mineral oil in sunflower oil

Following the discovery of mineral oil contamination of Ukrainian sunflower oil in April 2008, the Institute for Reference Materials and Measurements (IRMM) of the European Commission's Joint Research Centre (JRC) was requested by the Directorate General Health and Consumers (DG SANCO) to organise a proficiency test on the determination of mineral oil in sunflower oil. The aim of this test was to evaluate the comparability of analysis results gained by laboratories in the EU and the Ukraine. The organisation of the study and the evaluation of the results were done in accordance with “The International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories” and ISO Guide 43. Altogether 62 laboratories from 19 EU member states, Switzerland and the Ukraine subscribed for participation in the study. Four test samples at concentration levels between about 100 and 350 mg/kg, comprising contaminated crude sunflower oil, contaminated refined sunflower oil, and spiked sunflower oil, and a solution of mineral oil in n‐heptane were dispatched to the participants. The participants were asked to determine the mineral oil content of the test samples by application of their in‐house analysis methods. In total, 55 sets of results were reported to the organisers of the study. The performance of laboratories was expressed by z‐scores for the oil samples and by relative bias for the mineral oil solution in n‐heptane. The percentage of successful laboratories in the determination of the mineral oil content of sunflower oil was for all sunflower oil test materials about 80%.     

Influence of Extraction Method on Yield,Physicochemical Properties and Tocopherol Content of Manketti (<Emphasis Type="Italic">Schinziophyton rautanenii</Emphasis>) Nut Oil

The influence of extraction method on yield, physicochemical characteristics and tocopherol content of manketti nut oil extracted by four different methods has been determined. Soxhlet (SE) and supercritical fluid (SFE) extractions yielded 45.3 and 44.8%, respectively, while screw press and mechanical shaking extractions had 39.7 and 27.3%, respectively. SPE and SE extractions gave oils that had lower values of unsaponifiable matter (0.70; 0.74%) indicating lower amounts of minor components such as tocopherols (233.13; 290.68 µg/g oil), a greater extent of lipid peroxidation parameters; peroxide values (6.25; 3.01 mequiv O₂/kg), para‐anisidine values (10.22; 9.94), totox value (22.72; 15.96), flavour score (?0.25; 2.11), and high acid values (1.23; 1.03 mg KOH/g oil), respectively, compared to SFE and MSE oils. This was attributed to the high processing temperatures of SPE and SE extractions compared to SFE and MSE oils. Refractive indices (1.485–1.487), iodine values (127.97–129.07, Wijs) and density (0.908–0.914 g/cm³) were not affected by extraction method indicating that the oils generally had the same double bond content. Saponification values (182.98–192.95 mg KOH/g oil) and ester values (181.95–192.11), were not affected by extraction method except for SE oil which had lower values that were speculated to be due to co‐extraction with colour pigments.     

Ozonated Mineral Oil: Preparation,Characterization and Evaluation of the Microbicidal Activity

The ozonation of vegetable oils has been studied, since the produced ointments have antibacterial and fungicidal activities. However, the ozonation of mineral oils has not been reported in the literature yet, opening an interesting field for examination. In this work, we have shown the ozonation of a commercial mineral oil (Nujol). The main goal was to produce oils containing free ozone, so that this gas could act as antimicrobial agent. It was found that in Nujol, ozone remains for at least 40 days and in the sample ozonized for 15 h its concentration was 7.5 mg mL^?1. Neat Nujol showed no antimicrobial activity against the tested microorganisms, however, when ozonated it showed antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus and Escherichia coli.     

Feruloylated Products from Coconut Oil and Shea Butter

The synthesis of feruloylated coconut oil and feruloylated shea butter were demonstrated in 0.5-L scale, shaken, batch reactions. Ethyl ferulate and the vegetable oil/fat were combined in a 1.0:1.3 mol ratio in the presence of Candida antartica lipase B immobilized on an acrylic resin (Novozym 435) at 60 °C. The transesterification of ethyl ferulate with coconut oil and shea butter reached equilibrium conversions, after 22 days, of 63 and 70%, respectively, with the shea butter transesterifications producing a white precipitate not observed in the coconut oil transesterifications. The faster transesterification rates, equilibrium conversions and white precipitate were shown to result from di- and monoacylglycerols (DAG and MAG) present in the shea butter. The transesterification of ethyl ferulate and coconut oil was also tested in a continuous, enzymatic, packed-bed bioreactor using Novozym 435 at 60 °C to produce feruloylated coconut oil at rates of 0.5–0.9 kg/day over 4.5 months. The feruloylated coconut oil acylglycerol species were identified by LC–MS analysis of transesterification reactions of ethyl ferulate with medium chain triacylglycerol (TAG) standards, C8–C14. The feruloylated vegetable oils possessed an ultra violet (UV) absorbing λ _max 328 nm, making them good UVAII absorbers, as defined by the U.S. Food and Drug Administration. The feruloylated coconut oil possessed a 17.5% higher absorption capacity than feruloylated shea butter on a per weight basis. All the feruloylated vegetable oils possessed rapid antioxidant capacity (50% reduction of initial radical concentration <5 min) at the concentrations tested, 0.5–2.5 mM. Feruloylated coconut oil possessed chemical and physical characteristics that suggested it would be fungible for feruloylated soybean oil in current retail formulations.     

Linolenic Acid as the Main Source of Acrolein Formed During Heating of Vegetable Oils

Acrolein, which is an irritating and off-flavor compound formed during heating of vegetable oils, was estimated by the gas–liquid chromatography (GLC). Several vegetable oils such as high-oleic sunflower, perilla, rapeseed, rice bran, and soybean oils were heated at 180 °C for 480 min and then the concentration of acrolein in the head space gas was determined by GLC. The formation of acrolein was greatest in perilla oil among the tested oils, while it was much lower in rice bran oil and high-oleic sunflower oil. There was a good correlation between the level of acrolein and linolenate (18:3n-3) in the vegetable oils. To investigate the formation of acrolein from linolenate, methyl oleate, methyl linoleate, and methyl linolenate were also heated at 180 °C, and the amounts of acrolein formed from them were determined by GLC. The level of acrolein was the greatest in methyl linolenate. Acrolein was also formed from methyl linoleate, but not from methyl oleate. Acrolein in vegetable oils may be formed from polyunsaturated fatty acids, especially linolenic acid but not from glycerol backbone in triacylglycerols.