Acids In Vegetable Oils Research Articles

Benzyl Esters of Vegetable Oils as Processing Oil in Carbon Black–Filled SBR Compounding: Chemical Modification, Characterization, and Performance

ABSTRACTThree different types of benzyl ester were synthesized from vegetable oils (i.e., coconut oil, palm oil, and soybean oil). They were then utilized in styrene butadiene rubber (SBR) compound reinforced with carbon black. First, the benzyl esters were investigated by varying the molar ratio of fatty acids in vegetable oil to benzyl alcohol, the catalyst concentration, the reaction time, and the reaction temperature, observing the yield of benzyl ester. Then SBR was compounded with the benzyl esters, observing cure characteristics, mechanical properties, and morphologies of the SBR compounds, with the control compound containing conventional aromatic oil. The highest 96% yield of benzyl ester was obtained with palm oil fatty acid. Furthermore, the benzyl ester oils consumed less energy during processing but gave comparable carbon black dispersion, in comparison with the conventional aromatic oil.

Catalytic Vicinal Diacylation of Epoxidized Triglycerides in Canola Oil

AbstractThe epoxy ring opening and vicinal diacylation of fatty acids in vegetable oils was found to be promising reaction to synthesize stable biolubricants and bioplasticizers. The current research investigation is emphasized on the synthesis of a value added product vicinally diacylated canola oil by sulfated‐ZrO2. The two‐step research approach employed includes: (i) epoxidation, and (ii) epoxy ring opening and vicinal diacylation of epoxidized triglycerides in the canola oil. Sulfated‐ZrO2 was prepared and characterized to measure the physico‐chemical properties required for the effective catalysis. The Taguchi (L16 orthogonal array) statistical design method was employed to optimize the process conditions for the maximum formation of diacylated canola oil. Sulfated‐ZrO2 demonstrated promising activity for the epoxy ring opening and vicinal diacylation of canola oil, and 99 % conversion was achieved at the optimum process conditions of temperature 130 °C, epoxy to acetic anhydride molar ratio (1:1.25), 16 wt% of catalyst loading and reaction time of 1 h which were inferred from the Taguchi analyses. The products were characterized and confirmed with FT‐IR, 1H NMR and sodium spray mass spectroscopy. Spectroscopic analysis also confirmed the absence of intermediate products. The statistical analyses was undertaken to determine the order, rank and interactions among the process variables. The reaction followed Langmuir–Hinshelwood–Hougen–Watson type mechanism and the kinetic data was fitted in overall second order equation. Calculated apparent activation energy was 23.1 kcal/mol.

Dispersive liquid-liquid microextraction based on amine-functionalized Fe3 O4 nanoparticles for the determination of phenolic acids in vegetable oils by high-performance liquid chromatography with UV detection

A novel dispersive liquid-liquid microextraction method based on amine-functionalized Fe3O4 magnetic nanoparticles was developed for the determination of six phenolic acids in vegetable oils by high-performance liquid chromatography. Amine-functionalized Fe3O4 was synthesized by a one-pot solvothermal reaction between Fe3O4 and 1,6-hexanediamine and characterized by transmission electron microscopy and Fourier transform infrared spectrophotometry. A trace amount of phosphate buffer solution (extractant) was adsorbed on bare Fe3O4-NH2 nanoparticles by hydrophilic interaction to form the "magnetic extractant". Rapid extraction could be achieved while the "magnetic extractant" on amine-functionalized Fe3O4 nanoparticles was dispersed in the sample solution by vortexing. After extraction, the "magnetic extractant" was collected by application of an external magnet. Some important parameters, such as pH and volume of extraction and desorption solvents, the extraction and desorption time needed were carefully investigated and optimized to achieve the best extraction efficiency. Under the optimal conditions, satisfactory extraction recoveries were obtained for the six phenolic acids in the range of 84.2-106.3%. Relative standard deviations for intra- and inter-day precisions were less than 6.3 and 10.0%, respectively. Finally, the established method was successfully applied for the determination of six phenolic acids in eight kinds of vegetable oils.

Niobia supported on silica as a catalyst for Biodiesel production from waste oil

AbstractThe activity and stability of niobia supported on silica catalyst have been tested in continuous micro-pilot reactors, for biodiesel production starting from acid vegetable oils. A catalyst was prepared by the impregnation of silica pellets with a loading of 12% of Nb and was extensively characterized. The activity of this catalyst in both esterification and transesterification was tested in a continuous micro-pilot laboratory plant in which acid oil was fed (FFA 10% w/w) at a temperature of 220°C and at a pressure of 60 bar. The niobia based catalyst resulted in a very active catalyst in both esterification (FFA conversion = 95-90%) and transesterification reactions (FAME yield = 80-90%), and the activity remained quite constant for more than 100 h on stream. Notwithstanding this stability, a non-negligible leaching phenomena has been detected, in the case of long-time continuous runs, as the Nb concentration on the spent catalyst resulted lower than that on the fresh one. The obtained result confirms that the leaching of the active specie is one of the most strong problem in heterogeneous catalysis for biodiesel production.

Determination of short chain carboxylic acids in vegetable oils and fats using ion exclusion chromatography electrospray ionization mass spectrometry

A new method for quantification of short chain C1–C6 carboxylic acids in vegetable oils and fats by employing Liquid Chromatography Mass Spectrometry (LC–MS) has been developed. The method requires minor sample preparation and applies non-conventional Electrospray Ionization (ESI) liquid phase chemistry. Samples are first dissolved in chloroform and then extracted using water that has been spiked with stable isotope labeled internal standards that are used for signal normalization and absolute quantification of selected acids. The analytes are separated using Ion Exclusion Chromatography (IEC) and detected with Electrospray Ionization Mass Spectrometry (ESI-MS) as deprotonated molecules. Prior to ionization the eluent that contains hydrochloric acid is modified post-column to ensure good ionization efficiency of the analytes. The averaged within run precision and between run precision were generally lower than 8%. The accuracy was between 85 and 115% for most of the analytes. The Lower Limit of Quantification (LLOQ) ranged from 0.006 to 7mg/kg. It is shown that this method offers good selectivity in cases where UV detection fails to produce reliable results.

Эфиры этиленгликоля и жирных кислот растительных масел

Эфиры этиленгликоля и жирных кислот растительных масел

Enzymatic esterification of free fatty acids in vegetable oils utilizing different immobilized lipases.

Different immobilized lipases were screened for their ability to esterify free fatty acids (FFA) with monoacylglycerol (MAG) as acyl-group acceptor. A lipase from Rhizomucor miehei (Lipozyme RMIM) was the most suitable for lipase-catalyzed de-acidification-a promising alternative to conventional neutralization. A reduction of the FFA content to 0.6 % (w/w) was achieved by applying a substrate with an initial FFA-content of 6 % (w/w), the reaction at 50 °C for 22 h as well as the stepwise addition of a quadruple stoichiometric amount of MAG.

Photochemical behavior of sethoxydim in the presence of vegetable oils.

The photodecomposition of herbicides may be affected by adding vegetable oils to the spray tank. In this study nine vegetable oils were compared to assess the photodecomposition of sethoxydim under natural light conditions. The experiment was conducted as completely randomized factorial design with three replicates at the College of Agriculture, Ferdowsi University of Mashhad, Iran, in 2013. Each herbicidal solution (with and without vegetable oil) was exposed to sunshine with time intervals of 0, 5, 10, 20, 30, 60, 120, and 240 min. The results revealed that the half-life value was increased by adding castor bean and cottonseed oils to 1.39- and 1.18-fold, respectively, compared to nonvegetable oil. These values for turnip, olive, corn, soybean, sunflower, canola, and sesame oils were decreased down to 4.74-, 2.38-, 1.81-, 1.75-, 1.52-, 1.28-, and 1.11-fold, respectively. A positive relationship existed between the half-life of sethoxydim in the presence of vegetable oils and their viscosity. However, a negative relationship was monitored between unsaturated/saturated fatty acids ratio and the monounsaturated value with half-life. A positive relationship also existed between saturated fatty acids, polyunsaturated fatty acids, palmitic acid, and linoleic acid with half-life. This study revealed that the amount of fatty acids in vegetable oils is a determining factor in preventing or facilitating the photodecomposition of sethoxydim.

Rapid Separation of Free Fatty Acids in Vegetable Oils by Capillary Zone Electrophoresis

Olive oil is a very important product to human health since it inhibits formation of free radicals, tumour growth, lesions and inflammatory substances. High concentrations of free fatty acids in olive oils results in lipid deterioration due to oxidative or hydrolytic rancidity. To optimise an alternative capillary zone electrophoresis methodology, under ultraviolet indirect detection and to determine free fatty acids in edible vegetable oils without derivatisation steps in sample preparation. The condition used consisted of 15 mm NaH2 PO4 -Na2 HPO4 at pH ~6.86, 4.0 mm of sodium dodecybenzenesulphonate, 8.3 mm of Brij 35®, 45% v/v of acetonitrile and 2.1% of 1-octanol, injection at 12.0 mbar of pressure for 4 s, +19 kV of applied voltage and indirect detection at 224 nm, within an analysis time of 11 min. The capillary zone electrophoresis method was successfully applied to determination of free fatty acids in extra virgin olive oil, virgin olive oil and soybean oil samples. The comparison with the official volumetric titration method showed no significant difference within the 95% confidence interval. The main advantage to the proposed method is the possibility to observe the individual amount of the free fatty acids, which would be useful for researchers interested in studying the effect of the free fatty acids profile on oxidative process in food.

Phenylsulfonic acid functionalized mesoporous SBA-15 silica: A heterogeneous catalyst for removal of free fatty acids in vegetable oil

In this work, the phenylsulfonic acid functionalized SBA-15 silica was prepared by the reaction of mesoporous SBA-15 silica with phenyltrimethoxysilane, followed by the sulfonation with chlorosulfonic acid. The functionalized SBA-15 silica was then tested as a heterogeneous acid catalyst in the esterification of free fatty acid (FFA) present in vegetable oils with methanol. The textural feature and structure of the solid catalyst were investigated by using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS), thermo gravimetric analysis (TG) and nitrogen adsorption–desorption techniques. When 7wt.% of the solid catalyst and 15:1M ratio of methanol to oil were used in the esterification reaction, the FFA conversion to methyl esters of 96.7% was attained after 5h of reaction at a temperature of 67°C. It is shown that the heterogeneous acid catalyst possesses a good stability.

Determination of fatty acids in vegetable oils using comprehensive two-dimensional gas chromatography coupled to quadropole mass spectrometry

Comprehensive two-dimensional gas chromatography with quadropole mass spectrometry (GC x GC-qMS) was applied to the detection of 31 fatty acids in vegetable oils. The sets of columns, modulation period, scan range of quadropole mass spectrometer were optimized. The results demonstrated that the separation was achieved in 50 min with the column set of DB-1 (30 m x0. 25 mm x 0.25 microm) as the 1st column and DB-Wax (3.2 m x 0.1 mm x 0. 1 microm) as the 2nd column. All fatty acids were accurately and sensitively determined while the modulation period was 3.5 s and the scan range of quadropole MS was m/z 40-350. Most of the fatty acids were identified by NIST library spectra search, the other fatty acid isomers were identified by single standard injection analysis. When applying this method to the real vegetable oil samples, not only the sensitivities were 100 times higher than those obtained with GC-qMS methods, but also some minor fatty acids were identified. This work suggested a new technical approach in analyzing fatty acid components in vegetable oils, which is meaningful to prohibit adulteration and ensuring the quality safety of edible vegetable oils.

Effects of vegetable oils on biochemical and biophysical properties of membrane retinal pigment epithelium cells

The aim of this study was to investigate the effect of vegetable oil enrichment of retinal pigment epithelial (RPE) cells on their biochemical and biophysical properties. For this, RPE cells were incubated with 4 different vegetables oils (olive oil, corn oil, argan oil, and camelina oil). The cytotoxicity of these vegetable oils was assessed in vivo on 8-week-old mice and in vitro by using the neutral red and YO-PRO-1 tests. Membrane fluidity was evaluated by fluorescence anisotropy using the fluorescent probe diphenylhexatriene, and membrane fatty acid composition was assessed by gas chromatography. None of the oils tested displayed cytotoxic effects. In vitro, omega-3 rich oils improved membrane fluidity by 47% compared with the control cells. The omega-3 PUFA content within membranes decreased by 38% to 55% when cells were incubated separately with olive oil, corn oil, or argan oil, and increased when cells were incubated with a mixture of those oils, or with camelina oil alone (50% and 103% increase, respectively). Our results show that the fatty acids in vegetable oil incorporate into retinal cells and increase the plasma membrane fluidity.

The Detection of Glycerate and Free Fatty Acids by the Method of Near-Infrared Spectroscopy

The monoglyceride, diglyceride, triglyceride and free fatty acids in vegetable oil was detected by the analysis method of near-infrared spectroscopy. The near-infrared spectrograms of 77 oil samples were collected, including 67 samples for calibration set and 10 samples for prediction set. The Partial Least Squares (PLS) optimized models were established with OPUS chemical analysis software. The results demonstrated that the determination coefficient of monoglyceride, diglyceride, triglyceride and free fatty acids was 0.9691,0.8627,0.8742 and 0.9194, respectively. And the standard error of prediction for the four components was 0.0104, 0.1830.201 and 0.0106, respectively. The presented results showed that the analysis method of near-infrared spectroscopy can be used to identify the diglycerides and triglycerides, but as for monoglyceride and free fatty acids, further experimental verification is needed.

Cooling Rate Effects on the Microstructure, Solid Content, and Rheological Properties of Organogels of Amides Derived from Stearic and (R)-12-Hydroxystearic Acid in Vegetable Oil

Using safflower oil as the liquid phase, we investigated the organogelation properties of stearic acid (SA), (R)-12-hydroxystearic acid (HSA), and different primary and secondary amides synthesized from SA and HSA. The objective was to establish the relationship between the gelator's molecular structure, solid content, and gels' microstructure that determines the rheological properties of organogels developed at two cooling rates, 1 and 20 °C/min. The results showed that the presence of a 12-OH group in the gelator molecule makes its crystallization kinetics cooling rate dependent and modifies its crystallization behavior. Thus, SA crystallizes as large platelets, while HSA crystallizes as fibers forming gels with higher solid content, particularly at 20 °C/min. The addition to HSA of a primary or a secondary amide bonded with an alkyl group resulted in gelator molecules that crystallized as fibrillar spherulites at both cooling rates. Independent of the cooling rate, gels of HSA and its amide derivatives showed thixotropic behavior. The rheological properties of the amide's organogels depend on a balance between hydrogen-bonding sites and the alkyl chain length bonded to the amide group. However, it might also be associated with the effect that the gelators' molecular weight has on crystal growth and its consequence on fiber interpenetration among vicinal spherulites. These results were compared with those obtained with candelilla wax (CW), a well-known edible gelling additive used by the food industry. CW organogels had higher elasticity than HSA gels but lower than the gels formed by amides. Additionally, CW gels showed similar or even higher thixotropic behavior than HSA and the amide's gels. These remarkable rheological properties resulted from the microstructural organization of CW organogels. We concluded that microstructure has a more important role determining the organogels' rheology than the solid content. The fitting models developed to describe the organogels rheological behavior support this argument.

Using flaxseed oil to prepare therapeutical fat spreads

The present study aims to evaluate the suitability of flaxseed oil (rich plant source of long chain omega-3 polyunsaturated fatty acid) as healthy oil in formulation of therapeutic fat spread. Eight fat spread samples containing 20%, 40%, 60%, 80% total blend fat were prepared. Total blend fat used in preparing different fat spread samples were prepared by blending flaxseed oil at various ratios with palm oil. However, other four fat spread samples were prepared as control sample using palm oil and soybean oil at different ratios. Each fat spread sample was analyzed for its moisture, fat, protein, ash and carbohydrate content as well as its sensory properties and microbiological characteristics. Total blend fat extracted from each fat spread sample was also analyzed for its physical and chemical properties, oxidative stability and fatty acid profile. The obtained results showed that all formulated fat spread samples were found to be in good microbiologically characteristics as they were free from contamination by different microorganism groups. The eight formulated fat spreads contained zero-trans fatty acids. The fatty acid C16:0 was the predominant saturated fatty acid, in all prepared formulated fat spread samples, while, C18:3 was the highest unsaturated one (the only omega-3 fatty acid in vegetable oils) followed by C18:1, the highest C18:3 level of different fat spreads formulated from flaxseed oil is due to the highest percent of C18:3 in such oil. Incorporation of flaxseed oil into fat spread samples had marked effect on their contents of such fatty acid. Inversely, all fat spread samples prepared from flaxseed oil showed less oxidative stability compared to control samples, another decreasing effect on resistance against the oxidative rancidity occurred as flaxseed oil% increased in the formulation. No significant differences were observed for sensory properties resulted from using flaxseed oil in fat spread formulations.

Erucic acid evaluation in rapeseed and canola oil by Fourier transform‐infrared spectroscopy

AbstractA simple and rapid method was developed for the determination of erucic acid in rapeseed oil by single bounce attenuated total reflectance (SB‐ATR) Fourier transform infrared (FTIR) spectroscopy. The various ratios prepared from the three different types of oils (rapeseed, canola, and sunflower) were run on gas chromatograph to identify amount of erucic acid. Therefore, a wide range of erucic acid (0.5–53.0%) was obtained for the calibration. The partial least squares (PLS) calibration was used for predicting erucic acid using spectral region at 2983–657/cm. The root mean square error of prediction (RMSEP), root mean square error of calibration (RMSEC), and root mean square error of cross‐validation (RMSECV) were also determined to assess the accuracy of the method. The regression coefficient (R2) was obtained 0.999 with least errors of RMSEC (0.12%), RMSECV (1.96%), and RMSEP (1.38%). The accuracy of the FTIR method was evaluated by analyzing canola and rapeseed oil samples by GC‐MS and the results of both the techniques were found to be comparable.Practical applications: Generally, GC is used for determination of erucic acid in vegetable oils. But it needs the very laborious process of derivatization of fatty acids into their respective volatile methyl esters. Furthermore, lot of health hazardous chemicals and reagents are involved in the process of derivatization which are potential source for environmental pollution. Generally, FTIR spectroscopy has been recognized as a very simple, rapid, and cost effective technique. During the last decade, several researchers have used multivariate regression to build up calibration models based on FTIR data. The use of multivariate calibration methods is able to provide, estimates of the precision of the analysis, and yields important qualitative, quantitative, and analytical information. The objective of the present study was to develop a simple methodology for the quantitative analysis of low and high levels of erucic acid in canola and rapeseed oil, respectively by SB‐ATR FTIR spectroscopy with PLSs regression.

Use of hydroisomerization to reduce the cloud point of saturated fatty acids and methyl esters used in biodiesel production

Biodiesel, an alternative diesel additive made from renewable sources, has problems associated with their cloud points when used in colder climate. One method of improving the cloud point of biodiesel is hydroisomerization which branches the saturated portion of the biodiesel and lowers the cloud point of the compound. Palmitic acid methyl ester, which is the major saturated fatty acid in vegetable oils, is hydroisomerized with a 5 g kg−1 Pt impregnated beta zeolite catalyst at reaction conditions 200–285 °C and 1.0–4.0 MPa H2 pressure. FTIR and GC/MS analyses confirmed the branching and the identity of the reaction products. The cloud point of the material was lowered from 30 °C to 20 °C under reaction conditions of 285 °C and 4.0 MPa H2 pressure at the yield of 42% after 16 h. This study reports the hydroisomerization reaction being successful in branching the starting material in order to lower the cloud points of methyl esters.

Tin compounds as Lewis acid catalysts for esterification and transesterification of acid vegetable oils

Several catalysts based on tin compounds (tin(II) acetate, tin(II) chloride, tin(II) 2-ethylhexanoate and tin(II) stearate) have been tested in transesterification and esterification reaction in order to treat acid vegetable oils. All of them, except tin(II) stearate, showed good catalytic activity in transesterification reaching a methyl ester content higher than 96.5wt. % in 24h. When catalysts were tested in the simultaneous trans- and esterification of acid oil, the formation of water deactivated the catalyst tin(II) 2-ethylhexanoate. Best results were obtained with tin(II) acetate (methyl ester content, 96.6wt. % at 150°C and 3h). Finally, the reusability of tin(II) acetate was studied, because it could be recovered from the reaction by filtration.

In-vial liquid–liquid microextraction-capillary electrophoresis method for the determination of phenolic acids in vegetable oils

An in-vial liquid–liquid microextraction method was developed for the selective extraction of the phenolic acids (caffeic, gallic, cinnamic, ferulic, chlorogenic, syringic, vanillic, benzoic, p-hydroxybenzoic, 2,4-dihydroxybenzoic, o-coumaric, m-coumaric and p-coumaric) in vegetable oil samples. The optimised extraction conditions for 20g sample were: volume of diluent (n-hexane), 2mL; extractant, methanol: 5mM sodium hydroxide (60:40; v/v); volume of extractant, 300μL (twice); vortex, 1min; centrifugation, 5min. Recoveries for the studied phenolic acids were 80.1–119.5%. The simultaneous determination of the phenolic acid extracts was investigated by capillary electrophoresis (CE). Separations were carried out on a bare fused-silica capillary (50μm i.d.×40cm length) involving 25mM sodium tetraborate (pH 9.15) and 5% methanol as CE background electrolyte in the normal polarity mode, voltage of 30kV, temperature of 25°C, injection time of 4s (50mbar) and electropherograms were recorded at 200nm. The phenolic acids were successfully separated in less than 10min. The validated in-vial LLME-CE method was applied to the determination of phenolic acids in vegetable oil samples (extra virgin olive oil, virgin olive oil, pure olive oil, walnut oil and grapeseed oil). The developed method shows significant advantages over the current methods as lengthy evaporation step is not required.

Règlementation relative à l’étiquetage et aux allégations des produits alimentaires en général, et des huiles et matières grasses en particulier

Scientific research has evolved to identify relationship between nutrients and health effects. Theses scientific evidences can help to establish public health recommendations, which will be used by operators to formulate or optimize their food products. Labelling serves as a support for consumer information, raising its awareness about the food product nutritional composition. This enables the consumer to make an informed choice. Labelling also participates in the promotion of some of the food components, e.g. essential fatty acids in vegetable oils. In this context, regulation has evolved and allows operators to highlight nutritional benefits of their products via labelling information. Two different types of information must be distinguished: nutrition labelling and nutrition or health claims. The new European Regulation 1169/2011 on the provision of food information to consumers, published at the end of 2011, establishes a mandatory nutrition labelling with a fixed list of nutrients. Hence, food manufacturers are required to label the energy, fat, saturated fat, carbohydrate, sugars, protein and salt content of all their products. The Regulation on nutrition and health claims made on foods, published at the end of 2006, applies stringent rules to the use of claims and introduces the concept of a positive list for nutrition and generic health claims. This regulation aims at supporting public health recommendations and at providing the consumer with a high level of protection. A number of claims can be applied to vegetable oils. Nutrition labelling is an essential tool to disseminate and popularize scientific information in order to outreach consumers, as in the case of fatty acids, plant sterols or fat-soluble vitamins labeled in vegetable oils.