Chemometric Characterization of Eight Monovarietal Algerian Virgin Olive Oils

Differences in triacylglycerol, fatty acid, squalene, and tocopherol compositions were demonstrated between 8 varieties of virgin olive oils (Aberkane, Aguenaou, Aharoun, Aimel, Bouchouk Guergour, Bouichret, Chemlal, and Sigoise) from Petite Kabylie area, north eastern Algeria. Fatty acid and triacylglycerol morphotypes characterized each variety. A principal component analysis, based on triacylglycerol, fatty acid, and squalene compositions, differentiates between varieties. Minor fatty acids and squalene, usually not taken into account individually in authentication studies, are strongly involved in this differentiation, whereas the discriminant power of tocopherols is weak. Soft Independent Modeling of Class Analogy classification using chemical compositions as variables showed a high potential to authenticate the varietal origin of Algerian virgin olive oils.     

Characterization of Turkish Olive Oils by Triacylglycerol Structures and Sterol Profiles

A characterization study of Turkish monovarietal olive oils using chemical variables such as fatty acid, sn‐2 fatty acid, triacylglycerol, and sterol composition is presented. A total of 101 samples of Olea europaea L. fruits from 18 cultivars were collected for two crop years from west, south, and southeast regions of Turkey. Olives were processed to oil and olive oil samples were evaluated for their triacylglycerol structures and sterol composition. Oleic acid content ranged from 60.15 to 80.46 % of total fatty acids and represented 70.90–89.02 % of sn‐2 position triacylglycerols. Major triglycerides of oil samples were triolein, palmitodiolein, dioleolinolein, palmitooleolinolein, dipalmitoolein, and stearodiolein. Triolein values were between 24.72 and 48.64 % and compatible with the fatty acid composition. Total sterol content varied from 1,145.32 to 2,211.77 mg/kg and Edremit yagl?k stood out because of its high sterol content. A one‐way analysis of variance revealed significant differences for variables among cultivars. Principle component analysis enabled the classification of common varieties on the basis of analytical data. Sterol composition achieved more relevant discrimination than fatty acid and triglyceride composition. Classification according to geographical origin was performed by discriminant analysis.     

Development of a Novel High-Performance Thin Layer Chromatography–Based Method for the Simultaneous Quantification of Clinically Relevant Lipids from Cells and Tissue Extracts

Lipids such as cholesterol, triacylglycerols, and fatty acids play important roles in the regulation of cellular metabolism and cellular signaling pathways and, as a consequence, in the development of various diseases. It is therefore important to understand how their metabolism is regulated to better define the components involved in the development of various human diseases. In the present work, we describe the development and validation of a high-performance thin layer chromatography (HPTLC) method allowing the separation and quantification of free cholesterol, cholesteryl esters, nonesterified fatty acids, and triacylglycerols. This method will be of interest as the quantification of these lipids in one single assay is difficult to perform.     

Determination of fatty acid derivatives in fuel and diesel oil

Fuel oil plays one of the most important roles as thermal energy source in domestic application. Due to its common use, a careful monitoring of the grade and the deviation of the quality is required. Recently it has been observed that the presence of polar fatty acid derivatives is leading to problems in the fuel injection systems and consequently can cause a damage of the engine. A fast and reliably working procedure is presented, which allows the group determination of these polar compounds, namely glycerides, soaps and fatty acids. A sample preparation succeeded, which accomplishes the extraction, the clean up and the derivatization in one single reaction vessel. Derivatives were methylated with acetyl chloride and methanol and quantified with gas chromatography mass spectrometry. The complexity of fuel oil requires a careful elaboration of the clean up and the extraction procedure. Owing to the novelty of this procedure an accurate investigation and optimization of influential parameters were performed. Optimum conditions for the solid phase extraction with polar sorbents were provided for all target compounds. Additionally, the necessity of the clean up is shown with the relation between investigated analytes and matrix effects. Finally, method performance was verified with an accurate validation and analyses of spiked samples.     

Authentication of Commercial Extra Virgin Olive Oils

The goal of the current contribution is to determine the geographical origins of olive oil samples obtained from eight different countries during the harvest seasons of 2013 and 2014. First, the contents of olive oil samples were quantified by integrating the peaks of ¹H‐NMR spectra and using linear mathematical equations. The results were analyzed by analysis of variance (ANOVA), a statistical method examining whether there is a significant difference between the groups mean. The origins of the majority of the olive oil samples were discriminated by ANOVA and the minor constituents of the olive oils. Tocopherol and cycloartenol were the most discriminative minor constituents of the olive oil samples.     

Oxidative and flavor stability of oil from lipoxygenase-free soybeans

Soybeans that lack or contain three lipoxygenase (LOX) isozymes, LOX-1, LOX-2, and LOX-3, were evaluated for oxidative and flavor stability at 60°C in the dark and at 35°C in the light. Although the two types of soybeans had a similar genetic background, there were significant differences (P ≤ 0.01) in fatty acid percentages between the lipoxygenase-free and normal oils before and after storage at both temperatures. The linolenic acid content of oil from LOX-free germplasm before storage averaged 7.2%, while normal lines averaged 6.6%. The linoleic acid content after storage averaged 6.9% for LOX-free and 6.6% for normal oils. LOX-free oil was not significantly different from normal oil in flavor, as judged by a sensory panel, or in concentrations of volatiles during storage at either storage condition. LOX-free oil had less hexanal than normal oil before storage, but had significantly greater (P ≤ 0.05) levels after storage for two weeks at 35°C. Peroxide values of oil from LOX-free soybeans were significantly greater (P ≤ 0.01) than oil from the normal soybean after storage at 60 and 35°C. LOX-free oil had significantly greater (P ≤ 0.01) levels of α-, β-, and γ-tocopherols. In general, oil from LOX-free soybeans did not have improved flavor or oxidative stability. Differences between the two oil types in peroxide value and in production of a few volatiles were probably a result of the differences in initial fatty acid composition.     

Oxidative and flavor stability of oil from lipoxygenase-free soybeans

Soybeans that lack or contain three lipoxygenase (LOX) isozymes, LOX-1, LOX-2, and LOX-3, were evaluated for oxidative and flavor stability at 60°C in the dark and at 35°C in the light. Although the two types of soybeans had a similar genetic background, there were significant differences (P≤0.01) in fatty acid percentages between the lipoxygenase-free and normal oils before and after storage at both temperatures. The linolenic acid content of oil from LOX-free germplasm before storage averaged 7.2%, while normal lines averaged 6.6%. The linoleic acid content after storage averaged 6.9% for LOX-free and 6.6% for normal oils. LOX-free oil was not significantly different from normal oil in flavor, as judged by a sensory panel, or in concentrations of volatiles during storage at either storage condition. LOX-free oil had less hexanal than normal oil before storage, but had significantly greater (P≤0.05) levels after storage for two weeks at 35°C. Peroxide values of oil from LOX-free soybeans were significantly greater (P≤0.01) than oil from the normal soybean after storage at 60 and 35°C. LOX-free oil had significantly greater (P≤0.01) levels of α-, β-, and γ-tocopherols. In general, oil from LOX-free soybeans did not have improved flavor or oxidative stability. Differences between the two oil types in peroxide value and in production of a few volatiles were probably a result of the differences in initial fatty acid composition.     

Effect of Industrial Chemical Refining on the Physicochemical Properties and the Bioactive Minor Components of Peanut Oil

The effect of the industrial chemical refining process on the physicochemical properties, fatty acid composition, and bioactive minor components of peanut oil was studied. The results showed that the moisture and volatile matter content, acid value, peroxide value, and p‐anisidine value were significantly changed (P < 0.05) after the complete refining process. No significant variation (P > 0.05) in the iodine value was observed among all the peanut oil samples. Similar changes were observed in the DPPH radical scavenging activity and the total tocol content during chemical refining. In addition, chemical refining did not have much effect on the fatty acid composition, except for certain changes of several individual fatty acids. Moreover, the chemical refining resulted in 23.6, 23.1, and 9.5 % losses of squalene, total phytosterols, and total tocols (α, β, γ, δ‐tocopherols and α, β, γ, δ‐tocotrienols), respectively. The degumming–neutralization step caused the greatest overall reduction of these bioactive minor components. However, the concentrations of α‐tocotrienol and γ‐tocotrienol increased after full refining. Furthermore, chemical refining slightly changed the relative proportions of individual phytosterols and individual tocols.     

Fatty acid composition of melon seed oil lipids and phospholipids

Fatty acid compositions of crude melon seed oil from two different sources were compared. Melon seeds fromCitrullus vulgaris (syn.C. lanatus) contained phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and phosphatidylserine (PS), whereas melon seeds fromCitrullus colocynthis contained only PC and LPC, but not PS. Analysis of the total lipids revealed that the major fatty acid of the oils was 18:2n-6.Citrullus vulgaris seed oil contained 71.3% andC. colocynthis contained 63.4% of 18:2n-6. The predominant fatty acids in theC. vulgaris PC were 18:2n-6 (32.2%), 18:1n-9 (26.4%) and 16:0 (22.2%), whereas theC. colocynthis PC contained 44.6% of 18:1n-9 as the major fatty acid. The level of monoenes in theC. colocynthis variety (46.2%) was different from theC. vulgaris (27.3%). The major fatty acid in the LPC was 18:1n-9 for both varieties. Notably, theC. colocynthis variety did not contain any PS. The major fatty acids in theC. vulgaris PS were 18:1n-9 (37.9%) and 18:2n-6 (33.7%). Of all the phospholipids, LPC contained the greatest amount of monoenes, 48.6–52.4%.     

Virgin grape seed oil: Is it really a nutritional highlight?

In comparison to refined grape seed oil which is neutral in taste and smell, the virgin oil is characterized by a pleasant vinous and fruity aroma, which also reminds of raisins if high‐quality raw material is used for the production. Difficulties arise from the susceptibility of the raw material to microbial and enzymatic deterioration as a result of the high moisture content after pressing the juices from the grapes. Grape seed oil has a high content (70%) of linoleic acid, whereas the total part of unsaturated fatty acids amounts to about 90%. In comparison to other edible oils, the oil contains, in addition to tocopherols, antioxidant‐effective tocotrienols. During the oil pressing process, only a small amount of phenolic compounds is transferred into the oil (0.01 mg/g), while most of these nutritionally interesting components remain in the press cake. Here, the content of phenolic compounds is about 2000 times higher. During storage of virgin grape seed oil, the pleasant sensory attributes change, and more and more degradation products like ethyl acetate, acetic acid or ethanol are detectable. Parts of the seed material, which come into the oil during pressing, result in a faster impairment of the oil.     

A multivariate study of the relationship between fatty acids and volatile flavor components in olive and walnut oils

The relationships between FA and the volatile profiles of olive and walnut oils from Argentina were studied using GC and solid-phase microextraction coupled with GC-MS. The major volatiles were aldehydes and hydrocarbons, produced mainly through the oxidative pathways. n-Pentane, nonanal, and 2,4-decadienal were predominant in walnut oils, whereas nonanal, 2-decenal, and 2-undecenal were the most abundant components in olive oils. A multivariate analysis applied to the chemical data emphasized the differences between the oils and allowed us to see a pattern of covariation among the FA and the volatile compounds. The main differences between walnut and olive oils were the presence of larger amounts of short-chain (C₅–C₆) saturated hydrocarbons and aldehydes in the former and the greater quantities of medium-chain (C₇–C₁₁) compounds in olive oil. This can be explained by their different origins, mainly from the linoleic acid in walnut oil or almost exclusively from the oleic acid in olive oil.     

Comparison of techniques for the extraction of tobacco seed oil

The yield and fatty acid (FA) composition of the oil obtained from the seeds of a semi‐oriental tobacco (Nicotiana tabacum L.) plant, type Otlja, by various recovery techniques, which are: Soxhlet extraction (SE), maceration (ME), indirect and direct ultrasonic extraction (IUE and DUE, respectively) and cold pressing (CP), were compared. The solvent extractions of ground tobacco seeds (TS) were carried out by n‐hexane, while CP was used to recover the oil from the TS. The highest oil yield (32.9 g/100 g, i.e. 93% of the oil content in the seeds) was achieved by CP. Ultrasonically assisted solvent extractions appear to be inefficient in recovering the oil from the ground TS, as the oil yields were only 45–55% of the oil content, depending on the extraction conditions. Independently of the technique applied, linoleic acid was the major FA of the tobacco seed oil (TSO). The compositions of the TSO extracted by SE, ME, IUE and CP were very similar to each other, and the composition of the TSO recovered by DUE depended on the ultrasonic power input. The content of linoleic acid was reduced, while the content of saturated FA was increased by increasing the ultrasonic power from 5 to 50 W.     

Enrichment of phospholipids from neutral lipids in peanut oil by high-performance liquid chromatography

Phospholipids from crude peanut oil were enriched on a 2-cm silica column and subsequently separated from neutral lipids within the chromatographic system without prior concentration. Hexane effectively removed the bulk neutral lipids, leaving the adsorbed phospholipids on the silica precolumn. Individual phospholipids were separated from the remaining neutral lipids and from each other by using two mixed solvents and a gradient program. This method separates the phospholipids in approximately 27 min after the desired enrichment level has been reached. The research reported in this paper was a cooperative effort by the Agricultural Research Service of the United States Department of Agriculture and the North Carolina Agricultural Research Service, Raleigh, NC 27695-7625.     

Triacylglycerol Composition Profiling and Comparison of High‐Oleic and Normal Peanut Oils

Oilseed plants produce huge amounts of fatty acids (FA) stored as triacylglycerols (TAG) in seeds that give a great variation in their composition. The variety and content of TAG directly affect the nutrition and function of lipids. TAG composition of 12 high‐oleic and normal peanut oil samples were profiled by two‐dimensional liquid chromatography (2D LC) coupled with atmospheric pressure chemical ionization mass spectrometry (APCI‐MS). The statistical evaluation of the TAG profiles determined was conducted on the basis of multidimensional data matrix using Principal Component Analysis (PCA). The technique enabled the differentiation of high‐oleic oils from normal peanut oils—as results illustrated TAG of high‐oleic peanut oil were clearly different from those of normal peanut oils. High‐oleic and normal peanut oils had different profiles mainly in the contents of OOO, OPO and POL. This finding provided theoretical foundation for detecting the adulteration of edible oils and analyzing the nutrition and function of high‐oleic peanut oils.     

Effect of the extraction solvent polarity on the sesame seeds oil composition

This study highlights the effect of solvent polarity on the yield (Y%) and properties of oil extracted from Algerian sesame seeds. Extractions were carried out under Soxhlet conditions with the following solvents: hexane (Hx), ethanol (Eth), acetone (Ac), dichloromethane (Di), isopropanol (Iso), hexane:isopropanol (Hx:Iso), and chloroform:methanol (Chf:Me). The sesame oil yield obtained using different solvents ranged from 28.86 to 52.83%. Fatty acids and sterols analyses were performed by GC on capillary column. γ‐Tocopherol was the major tocochromanol compound detected by HPLC‐fluorescence. Fourteen fatty acids were identified, with the predominance of oleic and linoleic acids. The main sterol in sesame oil was β‐sitosterol, followed by stigmasterol, campesterol, and Δ⁵‐avenasterol which were present in lower concentrations. High correlations were found between arachidic, gadoleic, behenic, and lignoceric acids concentrations; these results were explained by the metabolic biosynthesis pathway of the biologically active long‐chain PUFA by successive elongation and desaturation. Principal component analysis (PCA) of the data obtained from sesame oil composition enabled an easy comparison of the different extraction solvents, and correlated their properties with the most characteristic components of the extracted oils with a view to understand solvent–oil interaction, and to establish the effects of extracting solvent on such oil composition. Practical applications: This study showed that the choice of solvent depends largely on the desired fraction to be extracted. Sesame oil was better extracted with less‐polar solvents but membrane‐associated lipids are more polar and require polar solvents capable of breaking hydrogen bonds or electrostatic forces. Owing to the differences in solvent capacity, the fatty acids, sterols, and tocopherols extracted along with the oil vary, leading to differences in the quality of the extracted oil. The results obtained in this study could be applied in industrial extraction to encourage the use of alternative extraction solvents.     

Effects of the flaxseed oil on the fatty acid composition of tilapia heads

The objective of this study was to evaluate the effects of adding flaxseed oil (FO) to feed on the incorporation of n‐3 PUFA in tilapia heads. Tilapia were given diets with increasing levels of FO (0.00, 1.25, 2.50, 3.75 and 5.00% for treatments A, B, C, D and E, respectively), as a source of LNA for 150 days. The proximate composition of the heads indicated high nutritional value and 40 FA (fatty acids) common to all treatments were identified in total lipids. Intake of LNA caused storage of LNA and sequential desaturation‐elongation to eicosapentaenoic acid (EPA) and DHA. With increasing levels of FO in the diet, the content of LNA in tilapia heads increased (1.7 and 14.0% for diets A and E, respectively), as well as the contents of EPA (0.1 and 0.9% for diets A and E, respectively) and DHA (0.5 and 1.8% for diets A and E, respectively). Adding FO to tilapia feed markedly increased the total content of n‐3 PUFA (3.0 and 21.1% for diets A and E, respectively), decreased the total content of n‐6 PUFA (41.3 and 24.9% for diets A and E, respectively), and consequently resulted in a decrease in the n‐6/n‐3 ratio (13.8 and 1.2 for diets A and E, respectively). Therefore, feeding tilapia with FO is a good way of valorizing this part of the fish by creating a valuable nutritional food source.