Stabilization of refined olive oil by enrichment with chlorophyll pigments extracted from Chemlali olive leaves

This paper presents the first investigation on the effect of enrichment refined olive oil by chlorophyll pigment extracted from Chemlali olive leaves during storage (6 months). The changes that occurred in the quality indices, fatty acids, sterol, and phenolic content were investigated during the storage of refined olive oil under RT (20°C) and accelerated conditions (50°C) in the dark. Additionally, the pigments (chlorophyll and carotene) changes during 6 months of oil storage were evaluated. At the end of the storage, more than 90% of chlorophyll pigments decomposed in all samples, while, carotene pigment loss was lower showing up to 60 and 85% loss for oil stored at 20 and 50°C, respectively, at the end of storage. The reduction of total phenolic compounds exhibited similar degradation profiles, being reduced by 5% and up to 60% for the enriched refined olive oil stored at 20 and 50°C in 6 months, respectively. In the fatty acid composition, an increase in oleic acid and a decrease in linoleic and linolenic acids were less significant in enriched than non‐enriched refined olive oil. On the other hand, sterol composition was less affected by storage in enriched oil samples. However, the sterol concentration of the oil samples showed an increase in β‐sitosterol, 24‐methylene cholesterol, stigmasterol, and a decrease in cholesterol, Δ5, 24‐stigmastadienol percentage at the end of storage. Based on the Rancimat method, the oils with added leaf pigment extract had the lowest peroxide value and the highest stability. After 6 months of storage, the oxidative resistance of refined olive oil fell to 0.2 and to zero for enriched refined olive oil stored at 20 and 50°C, respectively.     

Oil fractionation as a preliminary step in the characterization of vegetable oils by high-resolution 13C NMR spectroscopy

One hundred nine oil samples were separated chromatographically to obtain oil fractions with a decreased TAG content but with enhanced levels of the minor components that define oil genuineness and quality. The oils, which included virgin olive oils from different cultivars and regions of Europe and north Africa and refined olive, “lampante” olive, refined olive pomace, hazelnut, rapeseed, high-oleic sunflower, corn, grapeseed, soybean, and sunflower oils, were fractionated on a silica gel column with hexane/diethyl ether as the mobile phase eluent. The method was highly reproducible, and the fraction obtained contained about 15% unmodified TAG and 85% polar compounds, which included polymeric TAG, oxidized TAG, DAG, MAG, and FFA, in addition to other minor polar components of the oils. The presence of these compounds, in an enriched fraction, should provide information about the thermal, oxidative, and hydrolytic alterations of the oils, as well as many compounds of interest in determining oil genuineness. The results indicate that these fractions can provide more information than the original oils for NMR or other spectroscopic studies used in the determination of oil quality.     

Hypolipidemic Effects of Phospholipids (PL) Containing n-3 Polyunsaturated Fatty Acids (PUFA) Are Not Dependent on Esterification of n-3 PUFA to PL

Phospholipids (PL) containing n‐3 polyunsaturated fatty acids (PUFA) have beneficial effects of maintaining and promoting health compared with triacylglycerols (TAG) containing n‐3 PUFA or general PL. This study evaluated the effects of dietary PL containing n‐3 PUFA and elucidated the effects of the glycerophosphate structure and n‐3 PUFA on fatty acid (FA) metabolism in rats. Rats were fed a basal diet containing soybean oil alone, TAG containing n‐3 PUFA (1.8 %), soybean PL (2.7 %), PL containing n‐3 PUFA (2.7 %), or TAG containing n‐3 PUFA (1.8 %) + soybean PL (2.7 %). The present n‐3 PUFA‐supplemented diets had similar FA compositions, and the PL diets had similar PL compositions. TAG containing n‐3 PUFA reduced serum TAG contents, but did not affect serum cholesterol contents compared with soybean oil alone. PL diets containing n‐3 PUFA and the combination of TAG containing n‐3 PUFA and soybean PL resulted in decreased serum and liver TAG contents compared with the diet containing soybean oil alone, reflecting enhanced liver FA β‐oxidation. The results of this study show that TAG containing n‐3 PUFA with added soybean PL affects serum and liver TAG and cholesterol contents to a similar degree as PL containing n‐3 PUFA. TAG containing n‐3 PUFA and soybean PL are widely used as functional food ingredients and pharmaceutical constituents and are inexpensive compared with PL containing n‐3 PUFA. Therefore, the combination of TAG containing n‐3 PUFA and soybean PL has potential as a useful and inexpensive component of functional foods.     

Biochemical Characterization of Arbequina Extra Virgin Olive Oil Produced in Turkey

Varieties of the olive cultivar Arbequina have recently been cultivated in Turkey. The objective of the study is to characterize and evaluate extra‐virgin olive oils (EVOO) produced from Arbequina grown in the Aegean and Mediterranean regions of Turkey. Major and minor components such as carotenoids, squalene, phenolics and tocopherols were studied to assess their effects on product quality and health benefits. The samples, identified as ArbqI and ArbqA, were from the Izmir and Adana provinces, respectively. Samples were analyzed by GC‐FID to determine fatty acid composition, sterol composition, TAG profile and squalene content. Individual phenolic fractions were analyzed by LC–MS/MS and tocopherol isomers were determined by HPLC. According to the results obtained from this study; Total phenolic content (TPC) of the samples were 454.68 and 50.86 mg Gallic acid/kg oil for ArbqI and ArbqA, respectively. Hydroxytyrosol and tyrosol were determined to be the main phenols. The major tocopherol isomer found in ArbqI and ArbqA was α‐tocopherol with levels of 179.55 and 202.5 mg/kg oil, respectively. β‐Carotene levels in both samples were similar at 0.2 mg/kg. Findings of this study were compared with the literature on Arbequina olive oil produced in different countries. It was determined that Arbequina olive oil of high quality can be produced in Turkey, especially in the Aegean region.     

Characterization of the effects of β‐carotene on the thermal oxidation of triacylglycerols using HPLC‐ESI‐MS

RP HPLC method coupled to ESI‐MS was used for the analysis and characterization of the oxidation of model triacylglycerols (TAGs) in presence of β‐carotene. β‐Carotene was added to the TAGs and oxidized in the Rancimat at 110°C. The samples were separated isocratically using a mixture of isopropanol with methanol and a Phenomenex C18 column. β‐Carotene degradation was measured using high performance TLC. We found that β‐carotene plays an important role during the thermal degradation of high oleic acid model TAGs. Half of the β‐carotene was degraded before 3 h of thermal treatment. β‐Carotene significantly increases the peroxide value of the TAGs after the third hour, suggesting a pro‐oxidant action. However, different TAGs show different activity toward thermal treatment and β‐carotene. The LLL was found to be less stable, OLL and OLO were stable till 10 and 12 h respectively, while POO, OOO, and OSO were the stable TAGs till 14 h. In TAGs, replacing linoleic acid by oleic acid, the stability of the corresponding TAG was found to increase by 2 h. A new class of oxidized TAGs was reported for the first time, together with previously reported species. The proposed mechanism of formation and identification of the newly identified species have been explained. Among the oxidized species of TAGs, mono‐hydroperoxides, bis‐hydroperoxides, epoxy‐epidioxides, and epoxides were the major compounds identified.     

The Phase Behavior of γ-Oryzanol and β-Sitosterol in Edible Oil

The phase behavior of binary mixtures of γ‐oryzanol and β‐sitosterol and ternary mixtures of γ‐oryzanol and β‐sitosterol in sunflower oil was studied. Binary mixtures of γ‐oryzanol and β‐sitosterol show double‐eutectic behavior. Complex phase behavior with two intermediate mixed solid phases was derived from differential scanning calorimetry (DSC) and small‐angle X‐ray scattering (SAXS) data, in which a compound that consists of γ‐oryzanol and β‐sitosterol molecules at a specific ratio can be formed. SAXS shows that the organization of γ‐oryzanol and β‐sitosterol in the mixed phases is different from the structure of tubules in ternary systems. Ternary mixtures including sunflower oil do not show a sudden structural transition from the compound to a tubule, but a gradual transition occurs as γ‐oryzanol and β‐sitosterol are diluted in edible oil. The same behavior is observed when melting binary mixtures of γ‐oryzanol and β‐sitosterol at higher temperatures. This indicates the feasibility of having an organogelling agent in dynamic exchange between solid and liquid phase, which is an essential feature of triglyceride networks.     

Physicochemical Properties of <Emphasis Type="Italic">Acer truncatum</Emphasis> Seed Oil Extracted Using Supercritical Carbon Dioxide

Acer truncatum seed oil rich in nervonic acid was extracted using supercritical carbon dioxide. GC (Gas Chromatography) analysis revealed that the oil contained approximately 6.22% nervonic acid. The sn‐2 compositions were also determined using lipase hydrolysis. A total of 52 triacylglycerides (TAG) were tentatively identified in the oil using an ultra‐performance convergence chromatography (UPC²) coupled with quadrupole time‐of‐flight mass spectrometry (Q‐TOF‐MS) for the first time. In addition, the contents of phytosterols (1961.9–2402.8 μmol/kg) and β‐carotene (2.09–2.35 μmol/kg) were also quantified for the first time, along with tocopherols (2352.0–2654.3 μmol/kg). The γ‐tocopherol (1296.9‐1442.3 μmol/kg) was the primary tocopherol, while β‐sitosterol (1355.2–1631.3 μmol/kg) was the dominant phytosterol. The physicochemical properties of the oil were also investigated. This study indicated that A. truncatum seed oil is rich in nervonic acid and other nutraceutical constituents. It has a high potential in functional foods for improving human health.     

Triacylglycerols from viper bugloss (Echium vulgare L.) seed bio‐oil

Triacylglycerols (TAG) in viper bugloss oil were isolated from raw pressed oil by silicic acid column chromatography. The obtained blend of TAG was separated by silver ion thin‐layer chromatography (TLC Ag⁺) into nine fractions, varying in terms of unsaturation level and molecular polarity. The composition of TAG in viper bugloss oil was determined by HPLC coupled with a diode‐array detector and an evaporative light‐scattering detector. The results showed that the first three fractions were combinations of TAG containing palmitic, oleic and linoleic acids. Fractions 4 and 6 contained TAG of a similar acid composition as above, but with the addition of γ‐linolenic acid. The remaining fractions (7–9) were the most varied in acid composition. They were found to contain 26–39% palmitic acid, 12–15% oleic acid, 13–41% linoleic acid 8–24% γ‐linolenic acid, 1.5–5.5% α‐linolenic acid and 1–5% stearidonic acid. The analysis of fatty acid allocation in TAG of viper bugloss lipids revealed that linoleic acid (ranging from 2 to 100%) was the only acid found in all isolated fractions. In the investigated oil, the predominant TAG included: LnLnG (11.38%), LnLnSt (11.17%), LnGSt (7.71%), LnStSt (6.19%) and LnLnLn (5.44%). Almost 86% of the TAG contained α‐linolenic acid, while γ‐linolenic and stearidonic acids amounted to 49 and 38%, respectively.     

Physical State of β‐Carotene at High Concentrations in a Solid Triglyceride Matrix

The highly hydrophobic β‐carotene is often distributed or dissolved in triglycerides to enhance either nutritional or coloring effects. This study aims at elucidating the physical state of β‐carotene that at high concentrations are mixed into a solid high‐melting tri‐glyceride matrix by dissolution at high temperatures (165 °C) in the melted triglyceride. Extensive isomerization of β‐carotene is observed by HPLC after melting crystalline all‐trans β‐carotene and in the solid mixtures of β‐carotene and fully hydrogenated sunflower oil. Crystalline triglyceride is found in the mixed samples by XRPD analysis whereas no signs of crystalline lattice structures of β‐carotene are detected. DSC thermograms show only the melting and recrystallization events of triglycerides, which are affected by the presence of β‐carotene. Severe line broadening is observed in the ¹³C CP/MAS NMR spectra of the β‐carotene‐triglyceride mixtures when compared to crystalline β‐carotene, demonstrating the lack of long‐range order of the carotene. Altogether, the results demonstrate that β‐carotene is present as an amorphous mixture of trans‐ and cis‐isomers dispersed into a structure of crystalline triglyceride in the solid carotene‐triglyceride mixtures. Practical applications: The amorphous structure of trans‐ and cis‐isomers in solid formulations of β‐carotene‐triglyceride mixtures will strongly affect their functional properties related to nutrition and color as food ingredients.     

Effects of Phosphatidylcholine on Interaction of α-Tocopherol and β-Carotene in Photosensitized Oxidation of Emulsions

The interaction between α‐tocopherol (500 mg/kg) and β‐carotene (10 mg/kg) during chlorophyll‐photosensitized oxidation of a sunflower oil emulsion was studied in the presence or absence of phosphatidylcholine (PC, 250 mg/kg) by determining peroxide (POV) and conjugated dienoic acid (CDA) values. Chlorophyll, α‐tocopherol, β‐carotene, and PC contents in the emulsion were also monitored. α‐Tocopherol and β‐carotene individually and interactively decreased the POV and CDA values of oil in the emulsion by singlet oxygen quenching. PC decreased the POV and CDA values of oil, however, the values of the emulsion with added α‐tocopherol, β‐carotene, and PC were not significantly different from those of the emulsion with added α‐tocopherol and β‐carotene without PC. Contents of α‐tocopherol did not change during 24‐h oxidation, whereas co‐present PC significantly caused α‐tocopherol and chlorophyll degradation. β‐Carotene and PC contents significantly decreased to 45.5 and 51.3 %, respectively, after 24 h, and α‐tocopherol protected β‐carotene from degradation. The results suggest that PC had no net effects on the interactive antioxidant activity of α‐tocopherol and β‐carotene during chlorophyll‐photosensitized oxidation of the emulsion through free radical generation, chlorophyll degradation, and lessening the potency of α‐tocopherol as a singlet oxygen quencher.     

On‐line LC‐NMR‐MS characterization of sesame oil extracts and assessment of their antioxidant activity

Sesame lignans were isolated by solvent extraction and subsequently purified by solvent crystallization from crude, unroasted sesame oil, and a sesame oil deodorizer distillate. In addition, an aliquot of the purified sesame oil extract was treated with camphorsulfonic acid to obtain a sesaminol‐enriched extract. The sesame lignan composition of the extracts was characterized by on‐line liquid chromatography nuclear magnetic resonance spectroscopy mass spectrometry coupling (LC‐NMR‐MS). The effect of the sesame oil extracts as well as pure sesame lignans and γ‐tocopherol on the oxidative stability of sunflower oil (lignan‐free) was studied by the Rancimat assay. The Rancimat assay revealed the following oxidative stability order: sesame oil extract < sesame oil deodorizer distillate < sunflower oil (no added sesame oil extracts) < sesamol < sesaminol‐enriched sesame oil extract. In addition, the radical‐scavenging capacity of these extracts was assessed by the Trolox® equivalent antioxidant capacity (TEAC) assay. The TEAC assay revealed a slightly different AOX activity order: sesamin < sesame oil extract < sesaminol‐enriched sesame oil extract < sesamol. In conclusion, the sesaminol‐enriched extract revealed strong antioxidant activity and is therefore suitable to increase the oxidative stability of edible oils high in polyunsaturated fatty acids.     

Stereospecific distribution of fatty acids in triacylglycerols of olive oils

The positional distribution of fatty acids (FA) in triacylglycerols (TAG) of 47 virgin olive oils from diverse cultivars grown in distinct areas of North‐Eastern Italy was studied. Few data were previously available on oils from these geographical areas. The effects of climatic and geographical conditions on the stereospecific distribution of TAG in olive oil were confirmed. Moreover, the results of the stereospecific analysis were used to evaluate the preferential esterification position of each FA on the basis of the degree of unsaturation and the chain length. The data of the stereospecific analysis of olive oil TAG can contribute to the determination of the selectivity of olive fruit acyltransferases for distinct FA.     

Evaluation of MALDI-TOF/MS Technology in Olive Oil Adulteration

Adulteration of extra virgin olive oil (EVOO) by addition of other vegetable oils or lower-grade olive oils is a common problem of the oil market worldwide. Therefore, we developed a fast protocol for detection of EVOO adulteration by mass spectrometry fingerprinting of triacylglycerol (TAG) profiles based on MALDI-TOF/MS. For that purpose, EVOO TAG profiles were compared with those of edible sunflower oil and olive oil composed of refined olive oil and virgin olive oils. Adulteration of EVOO was simulated by addition of sunflower and mixture of refined olive oil and virgin olive oils at 1, 10 and 20% w/w. Results of mass spectrometry TAG profiling were compared with routinely assessed K values for identification of adulteration. MALDI-TOF/MS technology coupled with statistical analysis was proven as useful for detection of adulteration in EVOO at a rate down to 1%. In contrast, standard spectrophotometric methods failed to identify minor adulterations. In addition, the ability of MALDI-TOF/MS in detection of adulteration was tested on EVOO samples from different geographical regions. Results demonstrated that MALDI-TOF/MS technology coupled with statistical analysis is able to distinguish adulterated oils from other EVOO.     

Classification of Turkish Monocultivar (Ayvalık and Memecik cv.) Virgin Olive Oils from North and South Zones of Aegean Region Based on Their Triacyglycerol Profiles

In this study, a total of 22 domestic monocultivar (Ayval?k and Memecik cv.) virgin olive oil samples taken from various locations of the Aegean region, the main olive growing zone of Turkey, during two (2001–2002) crop years were classified and characterized by well‐known chemometric methods (principal component analysis [PCA] and hierarchical cluster analysis [HCA]) on the basis of their triacylglycerol (TAG) components. The analyses of TAG components (LLL and major fractions LOO, OOO, POO, PLO, SOO, and ECN 42–ECN 50) in the oil samples were carried out according to the HPLC method described in a European Union Commission (EUC) regulation. In all analyzed samples the value of trilinolein (LLL), the least abundant TAG, did not exceed the maximum limit of 0.5 % given by the EUC regulation for different olive oil grades. The ranges of abundant TAG, namely LOO, OOO, POO, PLO, and SOO, were 13.30–16.08, 37.27–46.36, 21.39–23.24, 4.93–7.03, and 4.72–6.00 %. The TAG data of Aegean virgin olive oils were similar to those of products from important olive‐oil‐producing Mediterranean countries was determined. Also, the estimation of major fatty acids (FA) was carried out by using a formula based on TAG data. The PCA results showed that some TAG components have an important role in the characterization and geographical classification of 22 monocultivar virgin olive oil. The Aegean virgin olive oil samples were successfully classified and discriminated into two main groups as the North and South (growing) subzones or Ayval?k and Memecik olives (cultivars) according to the HCA results based on experimental TAG data and calculated major FA profile.     

Oxidative stability of avocado oil

This study is concerned with the extent of oxidative deterioration and oil stability as determined by measuring peroxide and conjugable oxidation products (COP) values and AOM time of refined bleached avocado oil in comparison with refined soybean and olive oil. The formation of peroxides in avocado oil exposed to daylight at room temperature is similar to that of soybean oil but greater than that of olive oil. No differences were found in peroxide formation, oxodiene values and COP values between the tested oil stored in the dark, at 60 C and at room temperature. The COP ratio in oils stored at 60 C is similar for avocado and olive oil, but differs from that of soybean oil. The AOM stability time both for refined avocado and soybean oil was approximately 14 hr, and for refined olive oil was 15 hr. The extent of oxidative stability of crude avocado oil was determined by measuring peroxide value compared with crude olive oil. Crude avocado oil is very sensitive to oxidation when exposed to daylight and fluorescent light, in contrast to its stability in the dark at room temperature. The chlorophyll content in crude avocado oil is reduced rapidly on exposure to daylight and fluorescent light.     

Seed Oils of Five Black Tartary Buckwheat Cultivars with Biochemical Characterization and Antioxidant Properties

Black tartary buckwheat oils (BTBOs) were extracted from five major industrial tartary buckwheat cultivars grown under similar agronomical activities and environmental conditions. These oils were characterized for the bioactive compounds containing fatty acids, β‐carotene, lutein, α‐, β‐, δ‐ and γ‐tocopherol, and for their antioxidant properties. The total tocopherol contents that were obtained ranged from 704.66 to 1156.19 mg/kg, with γ‐tocopherol (588.98–977.91 mg/kg) as the main component. The concentration of lutein ranged from 253.14 to 429.63 mg/kg, which was almost ten times higher than that of β‐carotenoid (46.71–69.2 mg/kg), indicating that black tartary buckwheat seed oils were a good source of lutein. The predominant fatty acids were unsaturated oleic acid (C18:1) (35.27–40.61 %) and linoleic acid (C18:2) (38.25–42.90 %). Excellent values of 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH), diammonium salt (ABTS) radical scavenging activities were obtained and the highest oxygen radical absorbance capacity (ORAC) value of 13.89 mmol Trolox equiv/g oil was detected in the variety of Chuanqiao No. 1, which was clearly separated by principal component analysis (PCA) on the basis of the highest content of tocopherols and carotenoids. Moreover, the correlation analysis showed that tocopherols and carotenoids were the major contributors to the antioxidant activities of the BTBOs. This study demonstrates that lipophilic extraction in the tartary buckwheat seed contains many interesting bioactive compounds, which are beneficial for human health.     

Interesterification of sesame oil and a fully hydrogenated fat using an immobilized lipase catalyst in both batch and continuous‐flow processes

Lipase‐mediated interesterification of sesame oil and a fully hydrogenated soybean oil was studied at 70 °C in both a batch reactor (BR) and a continuous‐flow packed‐bed reactor (PBR) using four different initial weight ratios of substrates (90 : 10, 80 : 20, 70 : 30 and 60 : 40) with Lipozyme TL IM (Thermomyces lanuginosa) as the biocatalyst. Reaction rates were determined by following the dependence of the profile of the product triacylglycerols (TAG) on the reaction time (BR) or the space time (PBR) via RP‐HPLC‐ELSD. Product TAG identities were confirmed by HPLC‐APCI‐MS. Primary differences between the performances of the two reactors were the maximum level of net hydrolysis (ca. 3 and 10 wt‐% lower acylglycerols at equilibrium for the PBR and BR, respectively), the time or space time required to approach quasi‐equilibrium conditions, and less migration of acyl groups in the PBR trials. For the BR trials, quasi‐equilibrium conditions were approached in 4–6 h, while for the PBR trials short space times (15 min to 2 h) were sufficient to produce effluent compositions similar to equilibrium BR compositions. The predominant TAG families formed by interesterification were LLS, PSO, PSL, SSL, and SSO (L = linoleic; S = stearic; P = palmitic; O = oleic). Oxidative stabilities, melting profiles and solid fat contents were determined for selected reaction products.     

Preparation of stearidonic acid‐enriched triacylglycerols from Echium plantagineum seed oil

HPLC analysis of Echium plantagineum seed oil shows a complex triacylglycerol (TAG) profile. TAG species were separated on an analytical scale by HPLC and their fatty acid (FA) composition is reported. GLC analyses showed that some TAG fractions reached a stearidonic acid (SDA, 18:4n‐3) percentage significantly higher than that in the original oil. TAG separation on a bigger scale was also essayed, by means of a gravimetric normal‐phase chromatographic column, using silver ion‐silica gel as stationary phase. Gradient elution with solvents of increasing polarity was applied, allowing the separation of valuable TAG species containing γ‐linolenic acid (GLA, 18:3n‐6), α‐linolenic acid (ALA, 18:3n‐3) and SDA as the main constituents (more than 85% of the total FA). An enzymatic hydrolysis reaction showed the distribution of FA in the isolated species of TAG. SDA was the major FA in the sn‐2 position (more than 50% of total FA), followed by ALA (19%) and GLA (18.5%).     

Characterization and chemometric study of crude and refined oils from table olive by‐products

Table olive processing produces defective fruits and the conditioning operations give rise to solid by‐products which are processed to obtain oil. In this study, the most relevant characteristics of crude oils extracted from table olive by‐products were high average acidity values (4.5%, green olives; 8.1%, ripe olives), ECN42 values of 0.34 (green olives) and 0.10 (ripe olives), while 2‐mono‐palmitin averaged 0.92%. The overall content of sterols was 2257 mg/kg (green olives) and 1746 mg/kg (ripe olives), while the concentration of cholesterol was 36 mg/kg (green olives) and 19 mg/kg (ripe olives). The effect of refining was mainly reflected by a decrease in acidity and sterols. Although most characteristics were in agreement with the established regulation for olive oil, the overall trans fatty acid content, the low apparent β‐sitosterol content, and the relatively high cholesterol content prevented their inclusion into classes of crude or refined lampante or pomace olive oils, not even into the vegetable oil category. Therefore, the oils analyzed should be considered for non‐edible purposes. The physicochemical characteristics used for chemometric discrimination permitted discrimination among types of oils (crude, 100%; physically refined, 90%; chemically refined, 100%), elaboration styles (green and ripe olives, 100%) and cultivars (Gordal, Manzanilla, Hojiblanca and Cacereña, 100%), with the sterol composition being the most useful parameter for discrimination.     

Separation of Triacylglycerols from Edible Oil Using a Liquid Chromatography–Mass Spectrometry System with a Porous Graphitic Carbon Column and a Toluene–Isopropanol Gradient Mobile Phase

This study presented a rapid and practical method of separating triacylglycerol (TAG) from edible oil using high‐performance liquid chromatography (LC) coupled with atmospheric‐pressure chemical ionization (APCI)/mass spectrometry (MS) system with a porous graphitic carbon column (150 mm × 2.1 mm, 5 μm) and a toluene–isopropanol–formic acid mobile phase. After investigating the experimental conditions, the gradient toluene–isopropanol mobile phase containing 0.1% formic acid was changed from 50:50 to 80:20 in 30 min; the column temperature was set to 35 °C, and APCI/MS was used in the positive‐ion acquisition mode. The TAG retention displayed a special order and was summarized to fit as follows: S‐ECN (special equivalent carbon number) = 2CN (carbon number) ? 3dB (double bond number) – 5uFA (unsaturated fatty‐acid number). Then, the LC–MS method was applied to separate TAG in 6 vegetable oils, resulting in the recognition of 27 TAG in corn oil, 21 TAGs in olive oil, 22 TAG in sunflower seed oil, 28 TAG in soybean oil, 25 TAG in sesame oil, and 31 TAG in peanut oil. The TAG separation through the LC–MS method was rapid, reproducible, and durable.