Influence of triacylglycerol characterics on the determination of free fatty acids in vegetable oils by fourier transform infrared spectroscopy

A rapid and direct Fourier transform infrared (FTIR) spectroscopic method using a 25-μm NaCl transmission cell was developed for the determination of free fatty acids (FFA) in six important vegetable oils (corn, soybean, sunflower, palm, palm kernel, and coconut oils) that differ in fatty acid profile. The calibrations were established by adding either standard FFA (oleic, lauric acids) or a representative mixture of FFA obtained after saponification of the refined oils. For all oils, up to a FFA level of 6.5% for coconut oil, the best correlation coefficient was obtained by linear regression of the free carboxyl absorption at 1711 cm⁻¹. All correlation coefficients were greater than 0.993, and no significant difference between the calibration methods could be detected. Upon validation of the calibration, no significant difference (α=0.05) between the “actual” and the “FTIR predicted” FFA values could be observed. The calibration models developed for the six oils differed significantly and indicate the need to develop a calibration that is specific for each oil. In terms of repeatability and accuracy, the FTIR method developed was excellent. Because of its simplicity, quick analysis time of less than 2 min, and minimal use of solvents and labor, the introduction of FTIR spectroscopy into laboratory routine for FFA determination should be considered.     

Rapid methods for determination of free fatty acids contents in fatty oils

Rapid qualitative and quantitative methods for determining the free fatty acid (FFA) contents in common oils and fats are reported. Qualitative method is based on the type of color developed in the presence of BDH indicators (Universal and “678”) when a known excess of alkali is added to an alcoholic solution of oil or fat. By this method, low (0.0–0.25), medium (0.26–0.99) and high (1.0 and above) FFA levels in fatty oils may be distinguished. Quantitative method is a simplified modification of the usual procedure of determining the FFA contents of oils and fats by titration against standard alkali solution in the presence of BDH Universal or “678” indicator. The results of the rapid methods agree well with those of the standard AOCS method.     

Determination of Free Fatty Acids in Edible Oils with the Use of a Variable Filter Array IR Spectrometer

The feasibility of employing a portable variable filter array (VFA) IR spectrometer equipped with a transmission flow cell to quantitatively analyze edible oils or biodiesel feedstocks for free fatty acids (FFA) was evaluated. The approach to FFA determination employed was based on a previously reported FTIR method that involves the extraction of FFAs into methanol containing the base NaHNCN, which converts the FFAs to their salts, followed by measurement of the carboxylate absorbance at ~1,573 cm⁻¹ in the spectrum of the methanol phase. When this methodology was implemented on the low-resolution VFA-IR spectrometer, the analytical performance was comparable to that of conventional FTIR instrumentation at FFA concentrations of <1%. However, at higher FFA levels, the relatively weak pulsed IR source of the VFA-IR spectrometer was found to provide insufficient energy for accurate measurement of the carboxylate absorption superimposed on the strong methanol absorption at ~1,450 cm⁻¹. By changing the extraction solvent to ethanol (EtOH), good spectra and calibrations could be obtained over an FFA range of 0–5%, having an overall SD of ±0.07% FFA. Based on this assessment, a VFA-IR spectrometer provides an economical instrumental means for at-line monitoring of FFA levels in crude and refined edible oils and biodiesel feedstocks, capable of analyzing ~20–30 prepared samples per hour.     

Determination of olive oil free fatty acid by fourier transform infrared spectroscopy

A new procedure for determining free fatty acids (FFA) in olive oil based on spectroscopic Fourier transform infrared-attenuated total reflectance spectroscopy measurements is proposed. The range of FFA contents of samples was extended by adding oleic acid to several virgin and pure olive oils, from 0.1 to 2.1%. Calibration models were constructed using partial least-squares regression (PLSR). Two wavenumber ranges (1775–1689 cm⁻¹ and 1480–1050 cm⁻¹) and several pretreatments [first and second derivative; standard normal variate (SNV)] were tested. To obtain good results, splitting of the calibration range into two concentration intervals (0.1 to 0.5% and 0.5 to 2.1%) was needed. The use of SNV as a pretreatment allows one to analyze samples of different origins. The best results were those obtained in the 1775–1689 cm⁻¹ range, using 3 PLSR components. In both concentration ranges, at a confidence interval of α = 0.05, no significant differences between the reference values and the calculated values were observed. Reliability of the calibration vs. stressed oil samples was tested, obtaining satisfactory results. The developed method was rapid, with a total analysis time of 5 min; it is environment-friendly, and it is applicable to samples of different categories (extra virgin, virgin, pure, and pomace oil).     

Effects of Crude Rice Bran Oil Components on Alkali-Refining Loss

The effects of minor components in crude rice bran oil (RBO) including free fatty acids (FFA), rice bran wax (RBW), γ-oryzanol, and long-chain fatty alcohols (LCFA), on alkali refining losses were determined. Refined palm oil (PO), soybean oil (SBO) and sunflower oil (SFO) were used as oil models to which minor component present in RBO were added. Refining losses of all model oils were linearly related to the amount of FFA incorporated. At 6.8% FFA, the refining losses of all the model oils were between 13.16 and 13.42%. When <1.0% of LCFA, RBW and γ-oryzanol were added to the model oils (with 6.8% FFA), the refining losses were approximately the same, however, with higher amounts of LCFA greatly increased refining losses. At 3% LCFA, the refining losses of all the model oils were as high as 69.43–78.75%, whereas the losses of oils containing 3% RBW and γ-oryzanol were 33.46–45.01% and 17.82–20.45%, respectively.     

Differentiation of Lard From Other Edible Fats and Oils by Means of Fourier Transform Infrared Spectroscopy and Chemometrics

Fourier transform infrared (FTIR) spectra at mid infrared regions (4,000–650 cm⁻¹) of lard and 16 edible fats and oils were compared and differentiated. The chemometrics of principal component analysis and cluster analysis (CA) was used for such differentiation using FTIR spectra intensities of evaluated fats and oils. With PCA, an “eigenvalue” of about 90% was achieved using four principal components (PCs) of variables (FTIR spectra absorbances at the selected frequency regions). PC1 accounted for 44.1% of the variation, while PC2 described 30.2% of the variation. The main frequency regions that influence the separation of lard from other evaluated fats and oils based on PC1 are 2,852.8 followed by 2,922 and 1,464.7 cm⁻¹. Furthermore, CA can classify lard into its group based on Euclidean distance.     

Rapid Determination of Degradation in Frying Oils with Near-Infrared Spectroscopy

Measures of free fatty acids (FFA), total polar materials (TPM), and conjugated dienoic acids (CDA), typical indices of oil degradation, were analyzed in daily oil aliquots taken from soybean oils with different linolenic acid concentrations used to fry French fries. The oils also were scanned with a reflectance near-infrared spectrometer using a wavelength range of 350–2,500 nm. By using partial least squares and one-out cross validation, calibrations were developed to quantitatively determine FFA, TPM, and CDA by near-infrared spectroscopy (NIRS). The coefficients of determination (R ²) when compared to the standard methods were 0.973 for FFA, 0.984 for TPM, and 0.902 for CDA. NIRS was an accurate and fast method to determine FFA, TPM, and CDA in oxidized oils. The ability to obtain different parameters simultaneously makes NIRS a potentially valuable tool for food quality assurance.     

Application of a Handheld Portable Mid-Infrared Sensor for Monitoring Oil Oxidative Stability

This study evaluated the capabilities of a handheld mid-infrared (MIR) spectrometer combined with multivariate analysis to characterize oils, monitor chemical processes occurring during oxidation, and to determine fatty acid composition. Vegetable oils (corn, peanut, sunflower, safflower, cottonseed, and canola) were stored at 65 °C for 30 days to accelerate oxidation reactions. Aliquots were drawn at 5 day intervals and analyzed by benchtop and portable handheld mid-infrared devices (4,000–700 cm⁻¹) and reference methods (IUPAC 2301 [1], 2302 [1]; AOCS Cd 8-58 [2]; and Shipe 1979 [3]). PLSR and soft independent modeling of class analogy (SIMCA) models were developed for oil classification and estimation of oil stability parameters. Models developed from MIR spectra obtained with a benchtop spectrometer equipped with a 3-bounce ATR device resulted in superior discriminative performances for classifying oils as compared to those obtained from handheld spectra (single-bounce ATR). Models developed from reference tests and handheld spectra showed prediction errors (SECV) of 1 meq/kg for peroxide value, 0.09% for acid value and 2% for determination of unsaturated fatty acids in different oils. Spectral regions ~3,012–2,850 cm⁻¹ (C–H stretching bands/shoulders of fatty acids), ~1,740 cm⁻¹ (C=O stretching of esters), and ~1,114 cm⁻¹ (–C–O stretching) were found to be important for prediction. Handheld-FTIR instruments combined with multivariate-analysis showed promise for determination of oil quality parameters. Portability and ease-of-use makes the handheld device a great alternative to traditional methods.     

Determination of free fatty acids in crude palm oil and refined-bleached-deodorized palm olein using fourier transform infrared spectroscopy

A rapid direct Fourier transform infrared (FTIR) spectroscopic method using a 100 μ BaF₂ transmission cell was developed for the determination of free fatty acid (FFA) in crude palm oil (CPO) and refined-bleached-deodorized (RBD) palm olein, covering an analytical range of 3.0–6.5% and 0.07–0.6% FFA, respectively. The samples were prepared by hydrolyzing oil with enzyme in an incubator. The optimal calibration models were constructed based on partial least squares (PLS) analysis using the FTIR carboxyl region (C=O) from 1722 to 1690 cm⁻¹. The resulting PLS calibrations were linear over the range tested. The standard errors of calibration (SEC) obtained were 0.08% FFA for CPO with correlation coefficient (R ²) of 0.992 and 0.01% FFA for RBD palm olein with R ² of 0.994. The standard errors of performance (SEP) were 0.04% FFA for CPO with R ² of 0.998 and 0.006% FFA for RBD palm olein with R ² of 0.998, respectively. In terms of reproducibility (r) and accuracy (a), both FTIR and chemical methods showed comparable results. Because of its simpler and more rapid analysis, which is less than 2 min per sample, as well as the minimum use of solvents and labor, FTIR has an advantage over the wet chemical method.     

The importance of glycerol in the fatty acid industry

Historically, glycerol, a valuable by product of the fatty acid insutry, is priced higher in the market-place than any of the common fatty acids. Glycerol “credit” from fat-splitting, frequently in time of economic stress, makes the difference between a profitable stearic acid operation and an economically unsound one. Theoretical yields of glycerol for the common fats and oils range from 9–13.5%; practical plant yields, corrected for FFA and upgrading yield losses, are 9–12.8% on 100% glycerol basis, or 10.3–14.8% on an 88% glycerol basis. Glycerol “credit” per pound of fatty acid ranges from 1 to 3 cents/pound. Upgrading “sweetwaters” from splitting operations in the fatty acid industry requires removal of dissolved salts, elimination of color, and fat and oil impurities, concentration (evaporation of water) and/or distillation. For Twitchellized sweetwaters this generally involves (a.) lime treatment. (b.) filtration, (c.) evaporation to half-crude, (d.) precipitation of excess lime, (e.) filtration, (f.) evaporation to a concentration of 88–90%, and probably, (g.) distillation. For autoclave or continuous process sweetwaters the upgrading includes (a.) light lime treatment, (b.) filtration, (c.) evaporation concentration to 88–90%, and probably, (d.) distillation. Glycerol may also be upgraded by ion-exchange processing followed by evaporation concentration in which distillation may be eliminated. Ion-exclusion (Dow process) is also feasible. Many special triglyceride products are required of different fatty acid homolog distribution than those of the parent or hydrogenated fats and oils. These are prepared by splitting the fats or hydrogenated oils, fractionating the fatty acids, upgrading the glycerol, and recombining the desired fractionated acids with glycerol by reesterification. One example is high lauric triglyceride from coconut oil suited for use as a coco butter substitute.     

Analyses of lipids and oxidation products by partition chromatography. Dimeric and polymeric products

A liquid-partition chromatographic method was developed to determine dimers in fats. Silicie acid treated with 20% methanol in benzene served as the immobile phase. A mixture of 2% methanol in benzene was the mobile solvent. Chromatographic separation of free fatty acids from oxidized-deodorized oils gave three well-isolated fractions composed of unoxidized acids, dimeric or polymeric fatty acids, and polar fraction (ethyl ether eluate). Recovery of acidic materials from the column was essentially quantitative (96–100%), reproducibility was good, and the standard error of regression was ±0.26. A linear relationship exists between the dimer content of deodorized soybean oil and the peroxide value of the oil before deodorization. An increase of 1% in dimer concentration corresponds to an increase in peroxide value of approximately 40. Dimer content of different vegetable oils varied from 1 to 3%. The chromatographic method can be used to estimate the degree of oxidation that an oil has received before deodorization and to follow various phases of fat oxidation, polymerization, and processing. Presented at spring meeting, American Oil Chemists' Society, Dallas, Tex., April 4–6, 1960. This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U.S. Department of Agriculture.     

Assessing the Effects of Sunlight on the Photooxidation of Tropical Oils with Experimental and Computational Approaches

This study aims to investigate the influence of high-intensity sunlight radiation on the photooxidation of tropical oils (TO). Coconut oil (CNO), palm oil (PO), and palm kernel oil (PKO) were chosen for determining the indicators of photooxidation when exposed to and in the absence of sunlight for 7 weeks. The results showed a significant (P < 0.05) increase in free fatty acid (FFA) levels and peroxide value (PV) when the TO were exposed to sunlight. The iodine value and color content decreased significantly (P < 0.05) due to the decomposition of unsaturated FFA owing to the breaking down of the π-bonds and the degradation of color pigments during photooxidation. Fourier transform infrared spectroscopy (FTIR) analysis showed strong vibrational absorptions at 1721 and 3505 cm⁻³, 1720 and 3560 cm⁻³, and 1721 and 3554 cm⁻³ for the CNO, PO, and PKO samples exposed to sunlight, respectively. These bands can be attributed to the presence of secondary oxidation products, which were absent in the TO that were not exposed to sunlight. A simulation was performed to support the FTIR results, which also indicated peaks from the secondary oxidation products at 1744 and 3660 cm⁻³. The study also revealed that the rate of photooxidation was different for each TO. The rate of oxidation followed the order PO > PKO > CNO. In contrast, no notable changes were observed in the TO kept away from sunlight. These results suggest that exposing TO to sunlight influences their oxidation stability and quality.     

A Comparative Study of the Properties of Six Sudanese Cucurbit Seeds and Seed Oils

The proximate analysis of seeds and physicochemical properties of oils extracted from six Sudanese cucurbit seeds Cucumis mello var. agrestis, Cucumis melo var. flexuosus, Cucumis sativus, Citrullus lanatus var. colocynthoides, Cucumis prophetarum, and Luffa echinata were examined by established methods. For each variety, the proximate analysis showed ranges for moisture, protein, and carbohydrates as 3.70–6.87, 14.50–17.50, and 15.62–28.89% on a dry matter basis, respectively. The oils were extracted by Soxhlet using petroleum ether, with yields that ranged from 10.9 to 27.10% (wt/wt). The obtained extracted oils were subjected to phyiscochemical, fatty acid, and tocopherol analysis. The physicochemical characterization of the oil revealed that the refractive indices and relative densities of the oils fell within the narrow ranges of 1.334–1.442 and 0.874–0.920 g/cm³, respectively. Unsaponifiable matters ranged between 0.8 and 1.2 mg KOH/g, whilst peroxide values (PV) ranged from 2.3 to 4.1 meq/kg. The ranges of the values for free fatty acid (FFA %) were 1.2–4.0%. The predominant fatty acids were 16:0, 18:0, 18:1, and 18:2 with ranges of 8.9–14.2, 6.0–9.4, 14.6–32.1, and 43.6–65.5%, respectively. γ-Tocopherol was the predominant tocopherol in all samples ranging from 0.8 to 43.2% of the total tocopherols, followed by δ-tocopherol and α-tocopherol.     

An investivation of the extraction,refining and composition of oil from winged bean (Psophocarpus tetragonolobus [L.] D.C.)

Eleven winged bean accessions from Thailand were analyzed. Oil content ranged between 15 and 18%. Oleic and linoleic acids were the major fatty acids (62.5–64.5%) together with behenic (12.6–14.4%) and lignoceric acid (2.4–2.8%). Linolenic acid level was low and traces of 15-, 17- and 21-carbon acids (saturated and unsaturated) were found. No parinaric acid was detected. Campesterol, stigmasterol and β-sitosterol were the principal components of the unsaponifiable fraction. The extracted oil had a very low free fatty acid (FFA) content but was not completely liquid below 35 C. The refining of crude winged bean oil is reported. Oil produced by expeller had a strong, beany aroma but a negligible level of gums and a low level of FFA. Degumming and neutralizing were unnecessary; bleaching produced an attractive colored oil free from beany aroma. Crude solvent-extracted oils from whole and decorticated winged beans had appreciable contents of gums and higher FFA contents than expeller-produced oil. Laboratory refining demonstrated the strong interference on bleaching exerted by gums and FFA. Conventional refining by degumming, neutralizing, bleaching and deodorizing, and by physical refining produced high-quality oils having a good color, low FFA level and no taste or smell. The solid/liquid ratio of refined winged bean oil as a function of temperature was found to be unusual. Oil was extracted from whole and decorticated winged beans in a pilot solvent extraction plant designed to simulate a Rotocei. Winged bean flakes were not as mechanically strong as those from soybean but good oil extraction yields were obtained and a meal was produced having an oil content of less than 1% at 10% moisture. Whole winged beans were expelled in a small expeller (throughput 16.8 kg/hr). Cake was produced with a residual oil content of 3.3–5% in a single pass through the expeller.     

Analysis of Cod-Liver Oil Adulteration Using Fourier Transform Infrared (FTIR) Spectroscopy

Analysis of the adulteration of cod-liver oil with much cheaper oil-like animal fats has become attractive in recent years. This study highlights an application of Fourier transform infrared (FTIR) spectroscopy as a nondestructive and fast technique for the determination of adulterants in cod-liver oil. Attenuated total reflectance measurements were made on pure cod-liver oil and cod-liver oil adulterated with different concentrations of lard (0.5–50% v/v in cod-liver oil). A chemometrics partial least squares (PLS) calibration model was developed for quantitative measurement of the adulterant. Discriminant analysis method was used to classify cod-liver oil samples from common animal fats (beef, chicken, mutton, and lard) based on their infrared spectra. Discriminant analysis carried out using seven principal components was able to classify the samples as pure or adulterated cod-liver oil based on their FTIR spectra at the selected fingerprint regions (1,500–1,030 cm⁻¹).     

New FTIR method for the determination of FFA in oils

A rapid, practical, and accurate FTIR method for the determination of FFA in edible oils was developed. Analogous to the AOCS titration procedure, the FTIR FFA determination is effected by an acid/base reaction but directly measures the product formed rather than utilizing an end point based on an electrode potential or color change. A suspension of a weak base, potassium phthalimide (K-phthal) in 1-propanol (1-PrOH), is used to convert the FFA present in oils to their carboxylate salt without causing oil saponification, and differential spectroscopy is used to circumvent matrix effects. Samples are first diluted with 1-PrOH, then split, with one-half treated with the K-phthal reagent and the other half with 1-PrOH (blank reagent), their spectra collected, and differential spectra obtained to ratio out the invariant spectral contributions from the oil sample. Quantification of the percentage of FFA in the oil, expressed as %oleic acid, based on measurement of the peak height of the ν (COO⁻) absorption of the FFA salt formed, yielded a calibration with an SE of <0.020% FFA over the range of 0–4%. The method was validated by standard addition and the analysis of Smalley check samples, the results indicating that the analytical performance of the FTIR procedure is as good as or better than that of the standard titrimetric procedure. As structured, the FTIR procedure is a primary method, as calibration is not dependent on reference values provided by another method, and has performance criteria that could lead to its consideration as an instrumental AOCS procedure for FFA determination. The FTIR portion of the analysis is automatable, and a system capable of analyzing ∼60 samples/h was developed that could be of benefit to laboratories that carry out a large number of FFA analyses per day.     

Free fatty acid formation and lipid oxidation on milled rice

Milled rice was stored at 37°C and 70% humidity and sampled regularly for 50 d. Rice surface lipid was extracted with isopropanol and analyzed for free fatty acids (FFA) and conjugated diene (CD) contents. Diffuse reflectance Fourier transform infrared (DRIFTS) spectra of the rice samples were also obtained. FFA and CD levels increased together during rice storage and exhibited three distinct phases. DRIFTS identified a decrease in intensity at 1746 cm⁻¹ (ester, −C=O) and increases in intensity at 1731 cm⁻¹ (aldehyde, −CO) and 1714 cm⁻¹ (fatty acid, −C=O) during storage, which correlated well with the chemical analysis data. DRIFTS spectral data were analyzed by a partial least squares regression method to identify spectral regions that correlate strongly with measured FFA and construct prediction models. Overall, the mid-infrared region (4000–400 cm¹) gave the best model (R=0.98, root mean square error of cross-validation=0.05) and also predcted the FFA content of milled rice well. The DRIFTS technique has potential for use in studying qualitative chemical changes on the milled rice surface lipids and for predicting FFA on milled rice.     

Deacidification of olive oils by supercritical carbon dioxide

An investigation of the application of supercritical carbon dioxide (SC-CO₂) extraction to the deacidification of olive oils has been made to verify that the nutritional properties of the oil remain unchanged when this technique is applied. Preliminary runs at 20 and 30 MPa in the temperature range of 35–60°C were performed on fatty acids and triglycerides as pure compounds or mixtures, to determine their solubility in SC-CO₂. The solubility data obtained show that CO₂ extracts fatty acids more selectively than triglycerides under specific conditions of temperature and pressure (60°C and 20 MPa). It has been noted that the physical state of the solutes plays an important role in determining the solubility trends as a function of temperature and pressure. Extraction of free fatty acids from olive oil was performed on samples with different free fatty acid (FFA) contents at 20 and 30 MPa and at 40 and 60°C. Experimental data suggest that the selectivity factor for fatty acids is higher than 5 and increases significantly as the fatty acid concentration of the oil decreases. For a FFA content of 2.62%, the selectivity reaches a value of 16. In order to evaluate any variations in the composition, several SC-CO₂ extractions of husk oil with high FFA content (29.3%) were made. The results show that selectivity is still significant (≈5) and the composition in the minor component of the deacidified oil has not changed. On the basis of the experimental results and preliminary process evaluations, the authors conclude that SC-CO₂ extraction could be a suitable technique for the deacidification of olive oils, especially for oils with relatively high FFA (<10%).     

Application of a Portable Handheld Infrared Spectrometer for Quantitation of <Emphasis Type="Italic">trans</Emphasis> Fat in Edible Oils

Trans fat poses serious health risks to consumers. In order to meet the FDA labeling requirements for trans fatty acids, development of fast, accurate, easy-to-use analytical methods for oils, fats and related products is desirable. Fourier transform infrared spectroscopy (FTIR) is a well-established analytical technique for quantifying trans fats, and the development of handheld FTIR units over the past decade presents new application opportunities. Our objective was to evaluate the performance of a handheld FTIR sensor for measuring trans fat content between 0.1 and 20% trans (w/w) in edible saturated and unsaturated oils. Calibration models were built by measuring height of the band at 966 cm⁻¹ and by partial least squares regression (PLSR) using benchtop FTIR as a reference method. Predictive accuracy of the models was validated with an independent test set of commercial edible oils. Calibration models developed using PLSR and linear regression of band heights gave correlation coefficients R ² > 0.98. Multivariate analysis for the handheld unit gave standard error of prediction (SEP) of approximately 1%, comparable to values obtained with benchtop systems. This study demonstrates that handheld FTIR spectroscopy coupled with chemometrics is a suitable method for quantitation of trans fat content.     

The content and composition of sterols and sterol esters in low erucic acid rapeseed (Brassica napus)

The low temperature crystallization technique for the enrichment of “minor” components, such as sterols and sterol esters, from vegetable oils was applied to low erucic acid rapeseed oils. The recovery of free sterols and sterol esters was estimated by use of¹⁴C-cholesterol and¹⁴C-cholesterol oleate. 80% of the free sterols and 45% of the sterol esters were recovered in the liquid fraction, while in two studies total recoveries were 95% and 99%, respectively. This technique showed some selectivity toward the sterol bound fatty acids when compared to direct preparative thin layer chromatography (TLC) of the crude oil. Gas liquid chromatography (GLC) analysis of the free and esterified sterols as TMS-derivatives showed very little selectivity in the enrichment procedure. The fatty acid patterns of the sterol esters demonstrated, however, a preference in the liquid fraction for those sterol esters which have a high linoleic and linolenic acid content. The content of free sterols was 0.3–0.4% and that of sterol esters 0.7–1.2% of the rapeseed oils in both winter and summer types of low erucic acid rapeseed (Brassica napus) when the lipid classes were isolated by direct preparative TLC of the oils. The free sterols in the seven cultivars or breeding lines analyzed were composed of 44–55% sitosterol, 27–36% campesterol, 17–21% brassicasterol, and a trace of cholesterol. The esterified sterols were 47–57% sitosterol, 36–44% campesterol, 6–9% brassicasterol, and traces of cholesterol and Δ5-avenasterol. The fatty acid patterns of these esters were characterized by ca. 30% oleic acid and ca. 50% linoleic acid, whereas these acids constitute 60% and 20%, respectively, of the total fatty acids in the oil. Little or no variation in sterol and sterol ester patterns with locality within Sweden was observed for the one cultivar of summer rapeseed investigated by the low temperature crystallization technique.