Tocopherol Content and Profile of Soybean: Genotypic Variability and Correlation Studies

Plant seed oils, including soybean seed oil, represent the major source of naturally derived tocopherols, the antioxidant molecules that act as free radical quenchers preventing lipid peroxidation in biological systems and vegetable oil products. All four isomers of tocopherols, i.e. α, β, γ, δ tocopherols that exist in nature are found in soybean seeds. The biological activity and the contribution of these isomers in improving the oxidative stability of vegetable oil are in reverse order. Because of the nutritive value and the importance for oil stability, enhancement of tocopherol content, through breeding programs, in soybean seeds has become a new and an important objective. Genotypic variability, which is the basis of every breeding program, is scarcely reported for tocopherol content and profile in soybean seeds. In the present investigation, the tocopherol content and profile in seed samples of 66 genotypes of Indian soybean were determined. The ratios observed between the lowest and the highest values for α, β, γ, δ, total tocopherol content were 1:13.6, 1:10.4, 1:7.5, 1:9.1, 1:7.9, respectively. The mean contents for α, β, γ, δ and total tocopherols were 269, 40, 855, 241 and 1,405 μg/g of oil, respectively. Total tocopherol content was the highest in ‘Co Soya2’ followed by ‘Ankur’. Concentration of α-tocopherol was the highest (27%) in ‘Ankur’ followed by ‘MACS124’ (26%) whereas gamma tocopherol concentration was the highest (69%) in ‘VLS1’ and ‘PK327’ followed by ‘MACS13’ (67%). In view of the fact that levels of unsaturated fatty acids, apart from tocopherols, also determine the oxidative stability of vegetable oils, the relationship of four isomers of tocopherols with each other as well as with different unsaturated fatty acids and oil content was also investigated in the present study. All the four isomers of tocopherols exhibited highly significant correlations with each other (p < 0.001) whereas γ-tocopherol and total tocopherol content showed a significant relationship with linoleic acid (p < 0.05).     

Effects of steeping conditions during wet-milling on the retentions of tocopherols and tocotrienols in corn

Vitamin E is a natural antioxidant that plays significant roles in food preservation and disease prevention. There are eight naturally occurring vitamin E isomers (tocols): α-, β-, γ-, and δ-tocopherols and α-, β-, γ-, and δ-tocotrienols. Corn oil is a major source of vitamin E. Most of the corn oil produced in the United States is a co-product of corn wet-milling. There is limited knowledge about the effects of corn wet-milling on the retention of these vitamin E isomers. A high-performance liquid chromatography method was developed for simultaneous determinations of tocols in steeped corn samples. Effects of steeping conditions (steeping time and SO₂ concentration) on retention of tocols in corn were investigated. α-Tocopherol, γ-tocopherol, α-tocotrienol, and γ-tocotrienol are the predominant vitamin E isomers in the corn variety used in the study. Steeping conditions had little effect on the concentration of α-tocopherol and α-tocotrienol. However, a higher concentration of SO₂ and a shorter steeping time gave a slightly higher γ-tocotrienol content and lower γ-tocopherol content. Corn kernels steeped in a vitamin C solution had a much higher concentration of the tocols than those steeped in SO₂ solution.     

The effect of bleaching and physical refining on color and minor components of palm oil

An industrially degummed Indonesian palm oil was bleached and steam refined in a pilot plant to study the effect of processing on oil color and on the levels of carotenoids and tocopherols. Five concentrations of one natural and two activated clays mixed with a fixed amount of synthetic silica were used for bleaching. For color measurement, the Lovibond method was compared to the CIE (Commission Internationale de l’Eclairage) L^*,a^*,b^* method. The results showed that the L^*,a^*,b^* method is repeatable and that the values found are highly correlated with the carotenoid content of bleached oil samples. The various clays and synthetic silica mixes removed 20–50% of the carotenoids in the degummed oil, depending on clay concentration and activity. For the two activated clays, pigment adsorption increased with clay amount. Steam refining totally destroyed carotenoids in the claytreated oils by heat bleaching. Total tocopherols in the crude oil amounted to 1000 mg/kg, with γ-tocotrienol as the main tocopherolic component followed by α-tocopherol, α-tocotrienol, and δ-tocotrienol. Tocopherol concentrations increased after the bleaching treatment with the most acid clay, and the increase was proportional to the amount of clay used. Both bleaching and steam refining changed the ratios between the various to copherolic components, especially increasing the relative concentration of α-tocotrienol in the refined oil. An average 80% tocopherol retention was obtained after the treatment with acid clay + synthetic silica and steam refining of palm oil.     

Oxidative Stability of Crude Mid-Oleic Sunflower Oils from Seeds with High γ- and δ-Tocopherol Levels

In this study, mid-oleic and high-oleic sunflower seeds were developed with high levels of γ- and δ-tocopherols by traditional breeding techniques. Sunflower seeds containing various profiles of tocopherols, ranging from traditional high α, low γ, low δ relative to those with high γ, high δ, and low α, were extracted, and the crude oil evaluated for oxidative stability. After aging at 60 °C, oils were measured for peroxide value and hexanal as indicators of oxidation levels. We found that when the γ-tocopherol content of mid-oleic sunflower oil (MOSFO) (NuSun) was increased from its regular level of 20 to 300–700 ppm, the oxidation of the oil was decreased significantly compared to MOSFO with its regular low γ-tocopherol level. The modified oils had α-tocopherol contents of up to 300 ppm without negatively affecting the stability of the oil. An oil with one of the best oxidative stabilities had a tocopherol profile of 470 ppm γ, 100 ppm δ, and 300 ppm α, indicating that MOSFO could be more oxidatively stable and still be a good source of Vitamin E from α-tocopherol. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

Intestinal Epithelial Cells Absorb γ-Tocotrienol Faster than α-Tocopherol

To elucidate the transepithelial transport characteristics of lipophilic compounds, the cellular uptake of tocopherol and tocotrienol isomers were investigated in Caco2 cell monolayer models. These vitamin E isomers formed mixed micelles consisting of bile salts, lysophospholipids, free fatty acid, and 2-monoacylglycerols, then the micelles were supplied to Caco2 cells. The initial accumulation of tocotrienol isomers in Caco2 cells was larger than those of corresponding tocopherol isomers. There was little difference among the cellular accumulations of four tocopherol isomers. These findings suggested that the difference between the molecular structures of the C16 hydrocarbon chain tail in tocopherol and tocotrienol was strongly responsible for the rapid epithelial transport into the Caco2 cells membranes rather than the difference in the molecular structures of their chromanol head groups. Furthermore, the secretion of α-tocopherol and γ-tocotrienol from Caco2 cells was investigated using Caco2 cells plated on a transwell. The time courses of their secretions from Caco2 cells showed that the initial secretion rate of γ-tocotrienol was also larger than that of α-tocopherol. To investigate the intestinal uptake of α-tocopherol and γ-tocotrienol in vivo, the mice were fed single doses of α-tocopherol or γ-tocotrienol with triolein. The γ-tocotrienol responded faster in plasma than α-tocopherol, although the maximal level of γ-tocotrienol was lower than that of α-tocopherol. This suggested that the intestinal uptake properties of administered α-tocopherol and γ-tocotrienol would characterize their plasma level transitions in mice.     

Frying Stability of Purified Mid-Oleic Sunflower Oil Triacylglycerols with Added Pure Tocopherols and Tocopherol Mixtures

To determine the effects of the addition of pure tocopherols to triacylglycerols, α, γ, and δ tocopherols were added singly and in various combinations to stripped mid-oleic sunflower oil (SMOSUN). Tortilla chips were fried in the treated oils and then aged at ambient temperature to determine storage stability of the fried food. Frying oils were evaluated for total polar compounds (TPC) as an indicator of oil deterioration, and they were also analyzed for retention of tocopherols. To determine effects of tocopherols on fried-food stability, chips were evaluated for hexanal as an indicator of oxidative stability and for odor characteristics by a trained, experienced analytical sensory panel. Oils extracted from the tortilla chips were also analyzed for residual tocopherols. TPC were highest in the SMOSUN control with no additives followed by the SMOSUN containing only α tocopherol. The SMOSUN oil containing γ tocopherol had the best fry life as indicated by the lowest TPC. Hexanal content and rancid odor intensity were highest in the chips fried in the SMOSUN control and in the SMOSUN containing only α tocopherol. The most stable tortilla chips were fried in SMOSUN containing all three (α, γ, and δ) tocopherols; however, the lowest hexanal levels were measured when γ and δ tocopherols were added at their highest concentrations.     

Separation of vitamin E (tocopherol,tocotrienol, and tocomonoenol) in palm oil

Previous reports showed that vitamin E in palm oil consists of various isomers of tocopherols and tocotrienols [α-tocopherol (α−T), α-tocotrienol, γ-tocopherol, γ-tocotrienol, and δ-tocotrienol), and this is normally analyzed using silica column HPLC with fluorescence detection. In this study, an HPLC-fluorescence method using a C₃₀ silica stationary phase was developed to separate and analyze the vitamin E isomers present in palm oil. In addition, an α-tocomonoenol (α−T₁) isomer was quantified and characterized by MS and NMR. α−T₁ constitutes about 3–4% (40±5 ppm) of vitamin E in crude palm oil (CPO) and is found in the phytonutrient concentrate (350±10 ppm) from palm oil, whereas its concentration in palm fiber oil (PFO) is about 11% (430±6 ppm). The relative content of each individual vitamin E isomer before and after interesterification/transesterification of CPO to CPO methyl esters, followed by vacuum distillation of CPO methyl esters to yield the residue, remained the same except for α−T and γ−T₃. Whereas α−T constitutes about 36% of the total vitamin E in CPO, it is present at a level of 10% in the phytonutrient concentrate. On the other hand, the composition of γ−T₃ increases from 31% in CPO to 60% in the phytonutrient concentrate. Vitamin is present at 1160±43 ppm, and its concentrations in PFO and the phytonutrient concentrate are 4,040±41 and 13,780±65 ppm, respectively. The separation and quantification of α−T₁ in palm oil will lead to more in-depth knowledge of the occurrence of vitamin E in palm oil.     

High performance liquid chromatography of the tocols in corn grain

A sensitive and selective method was developed for analyzing the tocol isomers in corn grain by high performance liquid chromatography (HPLC) with fluorescence detection. The relative proportions and the total amounts of the tocol isomers (α-tocopherol, α-tocotrienol, γ-tocopherol and γ-tocortrienol) varied greatly among the 15 corn inbreds that were examined. Although γ-tocopherol has traditionally been considered to be the predominant vitamin E isomer in corn, inbreds with equal or higher levels of α-tocopherol have been discovered. No tocotrienols were found in corn germ oil, only α-and γ-tocopherols. Analysis of the tocopherols of the germ oils of inbreds and their reciprocal crosses indicated that the proportions of the α- and γ-isomers and the total amount of the tocopherols are heritable. Presented at the 74th AOCS annual meeting, Chicago, 1983.     

A rapid method for the determination of vitamin E forms in tissues and diet by high-performance liquid chromatography using a normal-phase diol column

This paper describes a simple method for the analysis of tocopherols in tissues by which frozen tissues −70°C were pulverized at dry ice temperatures (−70°C) and immediately extracted with hexane. There was no need to remove the coeluting lipids from tissues by saponification, since at that level of neutral lipids in the sample, there was no reduction in fluorescence response. For the analysis of oil, in which large amounts of neutral lipids were coextracted, a 20% reduction of fluorescence response was observed, but the response was equal for all tocopherol forms, and was appropriately corrected. Saponification was used only when tocopherol esters were present, and only after an initial hexane extraction to remove the free tocopherols in order to avoid their loss by saponification, particularly non α-tocopherol and tocotrienols. All the tocopherols and tocotrienols were separated on a normal-phase diol (epoxide) column that gave consistent and reproducible results, without the disadvantages of nonreproducibility with silica columns, or the lack of separation with reversed-phase columns. The tocopherols were quantitated by using a tocopherol form not present in the sample as an internal tocopherol standard, or using an external tocopherol standard if all forms were present, or when the sample was saponified. Piglet heart and liver samples showed the presence of mainly α-tocopherol, with minor amounts of β- and γ-tocopherol and α-tocotrienol, but no δ-tocopherol. Only small amounts of tocopherol esters were present in the liver but not in the heart.     

Antioxidant effects of d-tocopherols at different concentrations in oils during microwave heating

The effects of d-tocopherols at different concentrations (50 to 1000 ppm) on the oxidative stability of ethyl linoleate and tocopherol-stripped oils were investigated under microwave heating conditions. Purified substrate oils were prepared by aluminum oxide column chromatography. After the addition of tocopherols (α-, β-, γ- or δ-) to the oils, peroxide, carbonyl andp-anisidine values were measured in the samples after heating in a microwave oven. Further, the residual amount of tocopherol homologues in the oils after heating was determined by high-performance liquid chromatography for evaluation of their effects at different concentrations on oxidative deterioration. Microwave heating resulted in some acceleration in the oxidation of the purified substrate oils. Optimum concentrations of tocopherols required to increase oxidative stability were 100 ppm for α-, 150–200 ppm for β- or γ- and 500 ppm for δ-tocopherol, respectively. The antioxidant effect of tocopherols decreased in the order α>β ≒ γ>δ at each level, in all substrates. Therefore, α-tocopherol was consumed first, followed by β- or γ-tocopherol, and δ-tocopherol was consumed more slowly. The tocopherols had no further significant antioxidant activity (P>0.05) at concentrations higher than 500 ppm.     

Antiproliferative and apoptotic effects of tocopherols and tocotrienols on normal mouse mammary epithelial cells

Studies were conducted to determine the comparative effects of tocopherols and tocotrienols on normal mammary epithelial cell growth and viability. Cells isolated from midpregnant BALB/c mice were grown within collagen gels and maintained on serum-free media. Treatment with 0–120 μM α-and γ-tocopherol had no effect, whereas 12.5–100 m μM tocotrienol-rich fraction of palm oil (TRF), 100–120 μM δ-tocopherol, 50–60 μM α-tocotrienol, and 8–14 μM γ- or δ-tocotrienol significantly inhibited cell growth in a dose-responsive manner. In acute studies, 24-h exposure to 0–250 μM α-, γ-, and δ-tocopherol had no effect, whereas similar treatment with 100–250 μM TRF, 140–250 μM α-, 25–100 μM γ- or δ-tocotrienol significantly reduced cell viability. Growth-inhibitory doses of TRF, δ-tocopherol, and a-, γ-, and δ-tocotrienol were shown to induce apoptosis in these cells, as indicated by DNA fragmentation. Results also showed that mammary epithelial cells more easily or preferentially took up tocotrienols as compared to tocopherols, suggesting that at least part of the reason tocotrienols display greater biopotency than tocopherols is because of greater cellular accumulation. In summary, these findings suggest that the highly biopotent γ- and δ-tocotrienol isoforms may play a physiological role in modulating normal mammary gland growth, function, and remodeling.     

Tocopherol—An intrinsic component of sunflower seed oil bodies

Oil bodies were removed from mature sunflower through wet grinding followed by filtration then centrifugation and recovered as the buoyant fraction. Washing this fraction with buffer (water-washed oil bodies, WWOB) or 9 M urea (urea-washed oil bodies, UWOB) resulted in the removal of extraneous proteins. SDS-PAGE of the proteins still associated with the oil body fraction after washing indicated that this effect was particularly dramatic with urea washing. Thirty-eight percent of the total seed tocopherol was recovered in WWOB after only one cycle of oil body recovery. The total phenolic content (TPC) of differentially washed sunflower seed oil bodies was used as a marker for the nonspecific association of phenolic compounds to oil bodies. This value decreased with increased removal of proteins from oil bodies, whereas the converse was true for tocopherol values, which increased from 214 mg total tocopherol kg⁻¹ WWOB [dry wt basis (dwb)] to 392 mg total tocopherol kg⁻¹ UWOB (dwb). The ratio of the four tocopherol isomers remained constant in the seed and oil body preparations (α:β:γ:δ approximately 94∶5∶0.5∶0.5). This work provides evidence that an intrinsic population of tocopherol molecules exists in the oil bodies of mature sunflower seeds.     

Tocopherols in sea buckthorn (<Emphasis Type="Italic">Hippophaë rhamnoides</Emphasis> L.) berry oil

The free tocopherol content in whole berries of six sea buckthorn cultivars grown in northeastern Poland and Belorussia was determined with HPLC. The total free tocopherol content in oil from whole berries was 101.4–128.3 mg/100 g of oil. α-Tocopherol was the predominant tocopherol of sea buckthorn berries, and only traces of γ-tocopherol were detected in the oil. α- and δ-Tocopherols constituted 62.5–67.9% and 32.1–37.5% of total tocopherol, respectively. The total free tocopherol content in oil of sea buckthorn cv. Nadbaltycka increased during maturation from 40.4 to 109.8 mg/100 g of oil. Green berries contained a marked amount of γ-tocopherol, but its content rapidly declined to traces when the color of berries turned from green to olive-yellow.     

Relative autoxidative and photolytic stabilities of tocols and tocotrienols

The relative stabilities of selected individual tocols and tocotrienols and of equimolar mixtures of either α- plus γ- or α- plus δ- tocopherols were determined in methyl myristate and methyl linoleate during autoxidation and photolysis. Solutions containing 0.05% of the appropriate tocopherol(s) or tocotrienols were subjected to UV light (254 nm) or to a flow of 4.3 ml/min of oxygen, both at 70 C. Tocopherols (T) and tocotrienols (T−3) were determined by gas chromatography without preliminary separation or purification. Under photolytic conditions, stabilities in increasing order in methyl myristate were γ-T−3<α-T−3<δ-T<α-T <γ-T<5,7-T<β-T and in methyl linoleate were α-T<α-T−3≤γ-T−3≤β-T≤5,7-T <γ-T<δ-T. A solvent effect on the initial rate of photolysis was observed for 5-methyl substituted tocols but not for the tocols with an unsubstituted 5-position or for the tocotrienols. Under autoxidative conditions, stabilities in increasing order in methyl myristate were α-T=α-T−3 <β-T−3<γ-T−3<δ-T−3<γ-T<δ-T=β-T and in methyl linoleate were α-T<α-T−3 <γ-T−3<β-T<γ-T<δ-T. Tocopherols were much more stable during autoxidation in methyl myristate than they were in methyl linoleate. In mixtures, there was no significant protection of α-tocopherol by either γ- or δ-tocopherol under any of the conditions used. However, α-tocopherol was highly effective in protecting γ- and δ-tocopherols in methyl myristate during both photolysis and autoxidation and in methyl linoleate during photolysis. During autoxidation in methyl linoleate, α-tocopherol protection of γ- and δ- tocopherols after 24 hr was slight tough measurable.     

Optimal tocopherol concentrations to inhibit soybean oil oxidation

The optimal concentration for tocopherols to inhibit soybean oil oxidation was determined for individual tocopherols (α-, γ-, and δ-tocopherol) and for the natural soybean oil tocopherol mixture (tocopherol ratio of 1∶13∶5 for α-, γ-, and δ-tocopherol, respectively). The concentration of the individual tocopherols influenced oil oxidation rates, and the optimal concentrations were unique for each tocopherol. For example, the optimal concentrations for α-tocopherol and γ-tocopherol were ∼100 and ∼300 ppm, respectively, whereas δ-tocopherol did not exhibit a distinct concentration optimum at the levels studied (P<0.05). The optimal concentration for the natural tocopherol mixture ranged between 340 and 660 ppm tocopherols (P<0.05). The antioxidant activity of the tocopherols diminished when the tocopherol levels exceeded their optimal concentrations. Above their optimal concentrations, the individual tocopherols and the tocopherol mixture exhibited prooxidation behavior that was more pronounced with increasing temperature from 40 to 60°C (P<0.05). A comparison of the antioxidant activity of the individual tocopherols at their optimal concentrations revealed that α-tocopherol (∼100 ppm) was 3–5 times more potent than γ-tocopherol (∼300 ppm) and 16–32 times more potent than δ-tocopherol (∼1900 ppm).     

Tocol levels in milling fractions of some cereal grains and soybean

Tocol levels in the milling fractions of rice, barley, corn, wheat, and soybeans were analyzed by HPLC with a fluorescence detector. Among all milling fractions tested in this study, rice germ had the highest total tocol levels. In the four milling fractions of barley, except pearling flour, all eight tocol isomers were detected, and they were more uniformly distributed than in any other cereal grains measured in this study. The total tocol and α-tocopherol levels of wheat germ were significantly (P<0.05) higher than the other wheat milling fractions. A significantly (P<0.05) higher proportion of γ-tocopherol was obtained from corn germ (71.5%) and endosperm (50.3%) than from corn hulls. Only four tocol isomers (α-, β-, γ-, and δ-tocopherol) were detected in soybean milling fractions; no tocotrienol isomers were detected. The δ-tocopherol level of soybean endosperm, although minor, was significantly higher than those in milling fractions of other cereal grains in this study.     

Application of supercritical fluid chromatography in the quantitative analysis of minor components (carotenes,vitamin E,sterols, and squalene) from palm oil

The application of supercritical fluid chromatography (SFC) coupled with a UV variable-wavelength detector to isolate the minor components (carotenes, vitamin E, sterols, and squalene) in crude palm oil (CPO) and the residual oil from palm-pressed fiber is reported. SFC is a good technique for the isolation and analysis of these compounds from the sources mentioned. The carotenes, vitamin E, sterols, and squalene were isolated in less than 20 min. The individual vitamin E isomers present in palm oil were also isolated into their respective components, α-tocopherol, α-tocotrienol, γ-tocopherol, γ-tocotrienol, and δ-tocotrienol. Calibration of all the minor components of palm as well as the individual components of palm vitamin E was carried out and was found to be comparable to those analyzed by other established analytical methods.     

Properties of α-, γ-, and δ-tocopherol in purified fish oil triacylglycerols

The effect of α-tocopherol (αTOH) (50–2000 ppm), γ-tocopherol (γTOH) (100–2000 ppm), and δ-tocopherol (δTOH) (100–2000 ppm) on the formation and decomposition of hydroperoxides in purified fish oil triacylglycerols (TAG) was studied. The tests were conducted at 30°C in the dark. Purified fish oil TAG oxidized very rapidly with no apparent induction period. The relative ability of the tocopherols to retard the formation of hydroperoxides decreased in the order αTOH> γTOH>δTOH at a low level of addition (100 ppm), but a reverse order of activity was found when the initial tocopherol concentration was 1000 ppm. This dependence of relative antioxidant activity on tocopherol concentration was caused by the existence of concentrations for maximal antioxidant activity for αTOH and for γTOH. An inversion of activity, on the basis of hydroperoxide formation, was observed for αTOH at 100 ppm and for γTOH at 500 ppm, whereas the antioxidant activity of δTOH increased with level of addition up to 1500–2000 ppm. None of the tocopherols displayed any prooxidant activity. All three tocopherols strongly retarded the formation of volatile secondary oxidation products in a concentration-dependent manner. At concentrations above about 250 ppm there appeared to be a linear relationship between rate of consumption of αTOH and initial αTOH concentration, in accordance with the linear relationship observed between the initial rate of formation of hydroperoxides and the initial αTOH concentration. The rate of consumption of γTOH also increased with initial concentration, but to a lesser extent than for αTOH. At high levels of addition the rate of consumption of δTOH was independent of initial concentration, appearing to reflect the greater stability of this tocopherol homolog and participation in reactions with lipid peroxyl radicals only. Presented in part at the AOCS annual meeting in San Diego, California, April 2000.     

Assessment of olive oil adulteration by reversed-phase high-performance liquid chromatography/amperometric detection of tocopherols and tocotrienols

A method involving reversed-phase high-performance liquid chromatography with amperometric detection has been developed for the analysis of tocopherols and tocotrienols in vegetable oils. The sample preparation avoids saponification. Recoveries of α-tocotrienol and γ-tocotrienol in extra virgin olive oil were 97.0 and 102.0%, respectively. No tocotrienols were detected in olive, hazelnut, sunflower, and soybean oils, whether virgin or refined. However, relatively high levels of tocotrienols were found in palm and grapeseed oils. This method could detect small quantities (1–2%) of palm and grapeseed oils in olive oil or in any tocotrienol-free vegetable oil and might, therefore, help assess authenticity of vegetable oils.     

Characterization of chilean hazelnut (Gevuina avellana mol) seed oil

The fatty acid composition, tocopherol and tocotrienol content, and oxidative stability of petroleum benzene-extracted Gevuina avellana Mol (Proteaceae) seed oil were determined. Positional isomers of monounsaturated fatty acids were elucidated by gas chromatography-electron impact mass spectrometry after 2-alkenyl-4,4-dimethyloxazoline derivatization. This stable oil (Rancimat induction period at 110°C: 20 h) is composed of more than 85% monounsaturated fatty acids and about equal amounts (6%) of saturated and polyunsaturated (principally linoleic) fatty acids. Unusual positional isomers of monounsaturated fatty acids, i.e., C_16:1 Δ¹¹, C_18:1 Δ¹², C_20:1 Δ¹¹, C_20:1 Δ¹⁵, C_22:1 Δ¹⁷, and presumably C_22:1 Δ¹⁹ were identified. The C_18:1 Δ¹² and C_22:1 Δ¹⁹ fatty acids are described for the first time in G. avellana seed oil. While only minute quantities of α-, γ-tocopherols and β-, γ- and δ-tocotrienols were found, the oil contained a substantial amount of α-tocotrienol (130 mg/kg). The potential nutritional value of G. avellana seed oil is discussed on the basis of its composition.