Fatty acid composition of oil from soybean leaves grown at extreme temperatures

Leaves from soybean (Glycine max (L.) Merr.) plants were assayed to determine if the relationship between temperature and relative fatty acid composition observed in the seed oil also existed for the triglycerides in the leaf oil. Leaf samples were harvested from eight soybean lines (A5, A6, C1640, Century, Maple Arrow, N78-2245, PI 123440 and PI 361088B) grown at 40/30,28/22 and 15/ 12°C day/night. At 40/30 and 28/22°C, seven fatty acids were observed at a level greater than 1.0%. These included the five major fatty acids found in the seed oil: palmitic (16:0), stearic (18:0), oleic (18:1), linoleic (18:2) and linolenic (18:3) acid; plus two fatty acids that had retention times the same as palmitoleic (16:1) and γ-linolenic (18:3 g) acid. In addition, an eighth fatty acid that had a retention time the same as behenic (22:0) acid was found in the leaves of all lines at 15/12°C. Palmitic, palmitoleic and stearic acid content did not differ significantly over temperatures. The oleic and linoleic acid content were each highest at 15/12°C, while the γ-linolenic and the linolenic acid content were each highest at 40/30°C. The fatty acid composition of the triglyceride portion of the leaf oil did not display the same pattern over temperatures as that observed for seed oil.     

Temperature effects on fatty acid composition during development of low-linolenic oilseed rape (Brassica napus L.)

The influence of temperature during seed development on the fatty acid composition of oilseed rape (Brassica napus L.) was studied in one low-linolenic and one conventional canola cultivar. The cultivar Regent produces seed oil with ∼20% linoleic acid (C18:2) and ∼8% linolenic acid (C18:3), whereas Stellar is relatively high in C18:2 (∼25%) and low in C18:3 (∼2.5%). Both cultivars were grown in the field, and the fatty acid compositions of the seed oils were monitored throughout the period of seed development. In the field, the content of saturated (C16:0+C18:0) and monounsaturated (C18:1) fatty acids in the seed oil increased when seed developed under high temperatures. C18:3 levels were higher in seed harvested at sites with lower average daily temperatures. The low C18:3 trait of the cultivar Stellar was relatively stable over environments. Both temperature and duration of exposure to the temperature during seed development affected the fatty acid composition of the seed in a controlled environment study. Plants subjected to a high-temperature treatment (30/25°C day/night) for 40 d produced seed with the lowest C18:3 content and the highest levels of C16:0+C18:0 and C18:1. This was observed in both cultivars.     

The plant geneticist’ contribution toward changing lipid and amino acid composition of safflower

Current research on the fatty acid composition of the seed oil of safflower (Carthamus tinctorius L.) has shown the following: (1) there is a possibility that the oleic acid content can be increased above 80%, though probably not above 85%, by use of modifying genes and the major geneol; (2) wild species do not look very promising as a source of genes for modifying fatty acid composition; (3) commercially grown high linoleic and high oleic types are temperature stable; (4) an experimental type with about equal amounts of oleic and linoleic acids is responsive to temperature, with high temperature increasing oleic acid and low temperature increasing linoleic acid; and (5) stearic acid in another experimental type with higher levels of stearic acid (5–10%) is reduced by low temperatures. One of seven papers presented at the Symposium, “The Plant Geneticist’s Contribution Toward Changing Lipid and Amino Acid Composition of Oilseeds,” AOCS Meeting, Houston, May 1971.     

Photooxidation of soybean oils as affected by triacylglycerol composition and structure

The photooxidation of soybean oil was determined and correlated with triacylglycerol composition and structure. Purified triacylglycerols were photooxidized at room temperature under fluorescent light. Rates of peroxide formation and total headspace volatiles were related positively (P<0.5 significance) to oxidizability (r=0.75, r=0.76); content of linolenic acid (r=0.80, r=0.85) and linoleic acid (r=0.61, r=0.57); linoleic acid on carbon 2 (r=0.64, r=0.64); and average number of double bonds (r=0.76, r=0.76). Negative correlations were observed with respect to oleic acid (r=−0.70, r=−0.70). Soybean oil stability was decreased by linolenic acid-containing triacylglycerols and increased by oleic acid-containing triacylglycerols. Trilinoleoylglycerol and dilinoleoyl-oleoylglycerol were the most important oxidation product precursors. However, for high-linolenic acid soybean oil, dilinoleoyl-linolenoylglycerol and trilinoleoylglycerol were the most important oxidation product precursors. The most abundant volatile produced from thermal decomposition at 140°C of photooxidized triacylglycerols was 2-heptenal, except for high-linolenic acid oils, where the most abundant volatile was propanal. The photooxidative stability of soybean oil triacylglycerols with respect to composition and structure is of interest for the development of soybean varieties with oils of improved odor and flavor stability. Presented at the 20th ISF World Congress 83rd Annual American Oil Chemists’ Society Meeting, May 10–14, 1992, Toronto, Canada.     

Soybean seed protein and oil contents and fatty acid composition adjustments by drought and temperature

Environmental stress during soybean [Glycine max (L.) Merr.] seed fill can alter the chemical composition of the seed and reduce yield, viability, and vigor. The effect of drought and high air temperature (AT) on soybean seed protein and oil contents have not been reported. The objective of this study was to characterize the protein and oil contents and fatty acid composition of soybean seeds after exposure to drought and high AT during seed fill. Experiments were conducted during two years, in which three drought-stress levels were maintained throughout seed fill. In Experiment I, “Gnome” soybeans were grown at daytime AT of 20 and 26°C, and in Experiment II “Hodgson 78” were grown at 27, 29, 33, and 35°C. Across experiments, severe drought increased protein content by 4.4 percentage points, while oil content decreased by 2.9 percentage points. As drought stress increased, measured by accumulating stress degree days, protein content increased linearly and oil content decreased linearly at each AT. Seeds from plants exposed to 35°C during seed fill contained 4.0 percentage points more protein and 2.6 percentage points less oil than those exposed to 29°C when averaged across drought stress levels. Drought had little effect on the fatty acid composition of the oil, but high AT reduced the proportion of the polyunsaturated components.     

Characteristics of tea seed oil in comparison with sunflower and olive oils and its effect as a natural antioxidant

A comparison of iodine values showed that the degree of saturation of tea seed oil (Lahjan variety) was intermediate between the oils of sunflowerseed (Fars variety) and olive (Gilezeytoon variety), and the saponification values of these three oils were similar. Tea seed oil consisted of 56% oleic acid (C18∶1), 22% linoleic acid (C18∶2), 0.3% linolenic acid (C18∶3), and therefore, on the basis of oleic acid, occupied a place between sunflower and olive oil. In studies at 63°C, the shelf life of tea seed oil was higher than that of sunflower oil and similar to olive oil. Tea seed oil was found to have a natural antioxidant effect, and it enhanced the shelf life of sunflower oil at a 5% level. In this study, tea seed oil was found to be a stable oil, to have suitable nutritional properties (high-oleic, medium-linoleic, and lowlinolenic acid contents), and to be useful in human foods.     

Effect of temperature on soybean seed constituents: Oil,protein, moisture,fatty acids,amino acids and sugars

Soybean plants were grown at day/night temperatures of 24/19 C until the beginning of seed development, and then transferred to 5 different temperature regimes (18/13, 24/19, 27/22, 30/25 and 33/28 C) in the CSIRO phytotron. Mature seeds that developed under these conditions were analyzed for variances in composition. Fatty acid composition was strongly affected by temperature: linolenic and linoleic acids decreased markedly whereas oleic acid increased as the temperature increased; palmitic and stearic acids remained unchanged. Oil content was positively correlated with temperature, and protein content increased at the highest temperature. Of the sugars analyzed, sucrose concentration decreased by 56% with a 15 C increase in temperature, and stachyose showed a slight reduction; other sugars remained unchanged. Amino acid composition was generally stable; however, methionine increased with increased temperature during seed development. Moisture content was unaffected.     

Oxidative stability of natural and randomized high-palmitic-and high-stearic-acid oils from genetically modified soybean varieties

The oxidative stability of soybean oil triacylglycerols (TAG) obtained from genetically modified soybeans was determined before and after chemical randomization. Soybean oil oxidative studies were carried out under static oxygen headspace at 60°C in the dark and oxidative deterioration was monitored by peroxide value, monometric and oligomeric oxidation products, and volatile compounds. Randomization of the soybean oil TAG improved the oxidative stability compared to the natural soybean oil TAG. Oxidative stability was improved by three factors. Factor one was the genetic modification of the fatty acid composition in which polyunsaturated acids (such as linolenic and linoleic acids) were decreased and in which monounsaturated fatty acids (such as oleic) and saturated acids (palmitic and stearic) were increased. Factor two was the TAG compositional modification with a decrease in linolenic and linoleic-containing TAG and an increase in TAG with stearic and palmitic acids in combination with oleic acid. Factor three was the TAG structure modification accomplished by an increase in saturated fatty acids and a decrease in linoleic and linolenic acids at the glycerol moiety carbon 2. Presented at the AOCS Annual Meeting & Expo, Chicago, IL, May 10–13, 1998.     

Oxidative stability of blends and interesterified blends of soybean oil and palm olein

Improvement of oxidative stability of soybean oil by blending with a more stable oil was investigated. Autoxidation of blends and interesterified blends (9∶1, 8∶2, 7∶3 and 1∶1, w/w) of soybean oil and palm olein was studied with respect to fatty acid composition, fatty acid location and triacylglycerol composition. Rates of formation of triacylglycerol hydroproxides, peroxide value and volatiles were evaluated. The fatty acid composition of soybean oil was changed by blending. Linolenic and linoleic acids decreased and oleic acid increased. The triacylglycerol composition of blends and interesterified blends was different from that of soybean oil. Relative to soybean oil, LnLL, LLL, LLO, LLP, LOO and LLS triacylglycerols were lowered and POO, POP and PLP were higher in blends and interesterified blends (where Ln, L, O, P and S represent linolenic, linoleic, oleic, palmitic and stearic acids, respectively). Interesterification of the blends leads to a decrease in POO and POP and an increase in LOP. Linoleic acid concentration at triacylglycerol carbon-2 was decreased by blending and interesterification. Rates of change for peroxide value and oxidation product formation confirmed the improvement of soybean oil stability by blending and interesterification. But, blends were more stable than interesterified blends. Also, the formation of hexanal, the major volatile of linoleate hydroperoxides of soybean oil, was decreased by blending and interesterification.     

Fatty acid composition of oil from soybean seeds grown at extreme temperatures

Temperature during seed development is known to influence the level of the various fatty acids in soybean [Glycine max (L.) Merr.] oil. In order to determine the range of values that can be obtained for each fatty acid, five lines (A5, C1640, N78-2245, PI 123440 and PI 361088B) known to possess low linolenic acid (18:3) levels, one line (A6) known to possess a high stearic acid (18:0) level, and two cultivars (Century and Maple Arrow) were grown at 40/30, 28/22, and 15/12°C day/night. At 40/30°C, high oleic acid (18:1), low linoleic acid (18:2), and low linolenic acid levels were obtained that were beyond the range of levels reported for the soybean germplasm. The linolenic acid levels for A5, C1640 and N78-2245 grown at 40/30°C were below 2.0%, and are the lowest values reported for soybean oil. A6 displayed a high level of stearic acid at 28/22 and 40/30°C but displayed a relatively low level at 15/12°C. This indicates that temperature may affect the expression of thefas ^a allele, which is responsible for high stearic acid levels in A6. The linolenic acid levels of PI 361088B and C1640, both possessing thefan allele, were the lowest for all lines grown at 15/12°C. Therefore, thefan allele is an appropriate source for the development of low linolenic acid lines adapted to cool areas.     

Effect of triacylglycerol composition and structures on oxidative stability of oils from selected soybean germplasm

The oxidative stability of soybean oil triacylglycerols was studied with respect to composition and structure. Crude soybean oils of various fatty acid and triacylglycerol composition, hexane-extracted from ground beans, were chromatographed to remove non-triacylglycerol components. Purified triacylglycerols were oxidized at 60°C, in air, in the dark. The oxidative stability or resistance of the substrate to reaction with oxygen was measured by determination of peroxide value and headspace analysis of volatiles of the oxidized triacylglycerols (at less than 1% oxidation). The correlation coefficients (r) for rates of peroxide formation (r=0.85) and total headspace volatiles (r=0.87) were related positively to oxidizability. Rate of peroxide formation showed a positive correlation with average number of double bonds (r=0.81), linoleic acid (r=0.63), linolenic acid (r=0.85). Rate of peroxide formation also showed a positive correlation with linoleic acid (r=0.72) at the 2-position of the glycerol moiety. A negative correlation was observed between rate of peroxide formation and oleic acid (r=−0.82). Resistance of soybean triacylglycerols to reaction with oxygen was decreased by linolenic (r=0.87) and increased by oleic acid (r=−0.76)-containing triacylglycerols. Volatile formation was increased by increased concentration of linolenic acid at exterior glycerol carbons 1,3 and by linoleic acid at the interior carbon 2. Headspace analysis of voltiles and high-performance liquid chromatography of hydroperoxides indicated that as oxidation proceeded there was a slight decrease in the linolenic acid-derived hydroperoxides and an increase in the linoleic acid-derived hydroperoxides. The oxidative stability of soybean oil triacylclycerols with respect to composition and structure is of interest to the development of soybean varieties with oils of improved odor and flavor stability. Presented at the 81st Annual American Oil Chemists' Society Meeting, Baltimore, MD, April 18–21, 1990.     

Association of seed size with genotypic variation in the chemical constituents of soybeans

Ten soybean genotypes grown in 1992 with seed size ranging from 7.6 to 30.3 g/100 seeds and maturity group V or VI were selected and tested for oil and protein content and for fatty acid composition. In these germplasm, protein varied from 39.5 to 50.2%, oil, 16.3 to 21.6%, and protein plus oil, 59.7 to 67.5%. Percentages of individual fatty acids relative to total fatty acids varied as follows: palmitic, 11.0 to 12.8; stearic, 3.2 to 4.7; oleic, 17.6 to 24.2; linoleic, 51.1 to 56.3 and linolenic, 6.9 to 10.0. Seed size showed no significant correlations with individual saturated fatty acids, protein or oil content. However, significant correlations were found between seed size and individual unsaturated fatty acids: positive with oleic, and negative with linoleic and linolenic. Oil and protein content were negatively correlated with each other. Among the major fatty acids, only the unsaturated were significantly correlated with each other: negative between oleic and linoleic or linolenic, and positive between linoleic and linolenic. A subsequent study with soybeans grown in 1993 generally confirmed these findings. Variation in relative percentages of unsaturated fatty acids andr values for most pairs of relationships were even higher than those obtained from the 1992 crop. Presented at the 85th AOCS Annual Meeting and Expo, Atlanta, Georgia, May 8–12, 1994.     

Phytosterol accumulation in canola, sunflower, and soybean oils: Effects of genetics, planting location, and temperature

To assess the potential of traditional selection breeding to develop varieties with increased phytosterol content, we determined concentrations of those sterols in canola, sunflower, and soybean seed oils produced from breeding lines of diverse genetic backgrounds. Seed oils were extracted and saponified, and the nonsaponifiable fractions were subjected to silylation. The major phytosterols brassicasterol, campesterol, stigmasterol and β-sitosterol, were quantified by capillary gas chromatography with flame-ionization detection. Canola contained approximately twice the amount of total phytosterols (4590–8070 μg g⁻¹) as sunflower (2100–4540 μg g⁻¹) or soybean (2340–4660 μg g⁻¹) oils. Phytosterol composition varied among crops as expected, as well as within a crop. Both genetic background and planting location significantly affected total phytosterol concentrations. Soybean plants were maintained from flower initiation to seed maturity under three temperature regimes in growth chambers to determine the effect of temperature during this period on seed oil phytosterol levels. A 2.5-fold variability in total phytosterol content was measured in these oils (3210–7920 μg g⁻¹). Total phytosterol levels increased with higher temperatures. Composition also changed, with greater percent campesterol and lower percent stigmasterol and β-sitosterol at higher temperatures. In these soybean oils, total phytosterol accumulation was correlated inversely with total tocopherol levels. Owing to the relatively limited variability in phytosterol levels in seed oils produced under field conditions, it is unlikely that a traditional breeding approach would lead to a dramatic increase in phytosterol content or modified phytosterol composition.     

Physical Properties and Fatty Acid Profiles of Oils from Black,Kidney, Great Northern,and Pinto Beans

Four common beans (black, kidney, great northern, and pinto) were extracted with hexane and found to contain about 2% triacylglycerols. The fatty acids in these bean oils were mainly linolenic (41.7–46 wt%), linoleic (24.1–33.4 wt%), palmitic (10.7–12.7 wt%) and oleic (5.2–9.5 wt%). Because of the high levels of polyunsaturated fatty acids, the bean oils had iodine values between 174 and 177 g/100 g (compared to 130 g/100 g for soybean oil). Yet, the bean oils exhibited high oxidative stability due to the presence of high amounts of tocopherols (2,670–2,970 ppm). The bean oils had lower pour points (−18 to −11 °C) compared to −9 °C for soybean oil. Among the four bean oils, kidney bean oil had the highest acid value (15.4 mg KOH/g) and kinematic viscosities over a wide range of temperatures.     

Studies in soap crystallization processes. Part III. Acid soap crystallization in the segregation of tall oil fatty acids

Tall oil fatty acids have been fractionated into 80–90% oleic acid, and 60–80% linoleic acid fractions, by precipitation of the oleic acid as acid soap from polar solvents. Sodium and potassium acid soaps are equally effective, but ammonium acid soaps require lower operating temperatures. The choice of solvent is not critical as regards degree of separation, but technically attractive filtration rates have been obtained only with methanol and acetone. Acidulation gives colorless oleic acid of very low rosin acid and unsaponifiable content, but with 5–10% of conjugated linoleic acid.     

Vernonia galamensis: A rich source of epoxy acid

A percolation extraction ofVernonia galamensis seed, affording 38.6% of crude vernonia oil is described. The dark colored crude oil was degummed with water, treated with activated charcoal and bleached with a neutral agent, to give a light colored oil (Lovibond: 0.9 red, 3.5 yellow). Gas chromatographic/mass spectrometric analysis of the refined oil indicates a relative fatty acid composition of 79–81% vernolic (cis-12,13-epoxy-cis-9-octadecenoic) acid, 11–12% linoleic acid, 4–6% oleic acid, 2–3% stearic acid, 2–4% palmitic acid, and a trace amount of arachidic acid.     

Trehalose-Induced Changes in Seed Oil Composition and Antioxidant Potential of Maize Grown Under Drought Stress

The present investigation was conducted to determine if foliar-applied trehalose (an osmoprotectant) could ameliorate the adverse effects of water shortage on maize seed oil composition and oil antioxidant potential. Drought stress significantly reduced the seed oil but increased oleic acid and linolenic acid contents of the oil with a concomitant decrease in linoleic acid content, which resulted in an increased oil oleic/linoleic ratio in both maize cultivars. Water stress also increased the seed oil α- γ- δ- and total tocopherols and flavonoids of both maize cultivars, however, oil phenolic content and oil antioxidant activity decreased. Exogenously applied trehalose positively influenced seed composition of both maize cultivars under non-stress and water stress conditions. Exogenous application of trehalose further increased the oil oleic and linolenic acid contents with a subsequent decrease in linoleic acid. Furthermore, exogenous application of trehalose increased the oil antioxidant activity in terms of oil DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity with an increase in oil tocopherols, total flavonoids and total phenolics contents.     

Measuring and Modeling Liquid–Liquid Equilibria for a Soybean Oil, Oleic Acid, Ethanol, and Water System

Vegetable oils can be deacidified by liquid–liquid extraction based on differences in polarity between triglycerides and fatty acids and differences in solubility. Information on the equilibrium between the phases of such systems is important for designing separation processes. The present paper reports experimental data for the extraction of fatty acid from soybean oil by (ethanol + water) as a mixed-solvent for system of soybean oil + oleic acid + ethanol + water at 30 °C at different water contents. The liquid–liquid equilibrium data of the systems were used to obtain interaction parameters in the universal quasi-chemical theory (UNIQUAC) activity coefficient model. These parameters can be used to predict equilibrium data of ternary and quaternary systems. The deviations between experimental and calculated compositions in both phases for each system using this model were calculated. The distribution coefficients and the selectivity factors of solvents for extraction of fatty acid from oil at 30 °C were calculated. Increasing of the water content as the co-solvent decreased the distribution coefficients and increased the selectivity factors of mixed-solvents, therefore considering the economical and practical aspects the optimum water content may be used for extracting oleic acid from soybean oil. We concluded that (ethanol + water) as a mixed-solvent can be used for extracting fatty acids from edible oils in a normal temperature.     

Investigating Some Physicochemical Properties and Fatty Acid Composition of Native Black Mulberry (<Emphasis Type="Italic">Morus nigra</Emphasis> L.) Seed Oil

The physicochemical properties of seed and seed oil obtained from the native black mulberry (Morus nigra L.) were investigated in 2008 and 2009. The results showed that the seed consisted of 27.5–33% crude oil, 20.2–22.5% crude protein, 3.5–6% ash, 42.4–46.6% carbohydrate and 112.2–152.0 mg total phenolics/100 g. Twenty different fatty acids were determined, with the percentages varying from 0.02% myristic acid (C14:0) to 78.7% linoleic acid (C18:2). According to the GC analysis of fatty acid methyl esters, linoleic acid (C18:2), followed by palmitic acid (C16:0), oleic acid (C18:1) and stearic acid (C18:0) were the major fatty acids, which together comprised approximately 97% of the total identified fatty acids. High C18:2 content (average 73.7%) proved that the black mulberry seed oil is a good source of the essential fatty acid, linoleic acid. Linolenic acid (C18:3) was also found in a relatively lower amount (0.3–0.5%). The α-tocopherol content was found to be between 0.17 and 0.20 mg in 100 g seed oil. The main sterols in the mulberry seed oil were β-sitosterol, Δ5-avenasterol, Δ5, 23-stigmastadienol, clerosterol, sitosterol and Δ5, 24-stigmastadienol. The present study stated that the native black mulberry seed oil can be used as a nutritional dietary substance and has great usage potential.     

Rapid Detection and Quantification by GC–MS of Camellia Seed Oil Adulterated with Soybean Oil

Camellia seed oil with high nutritional value is widely used in southern China and southeastern Asia for cooking. Due to the high price of camellia seed oil, fraudulent traders blended the oil with inexpensive oils to increase profits. In this paper, a new method was introduced to detect the adulteration of camellia seed oil with soybean oil by GC–MS with consideration of a parameter which was defined by the total content of oleic and linoleic acid, the oleic to linoleic acid ratio and the content of linolenic acid. Oils samples were prepared by blending pure camellia seed oil with pure soybean oil at levels from 1 to 50 %. Fatty acids esterified by TMSH and TBME in seconds were separated and identified by GC–MS. The detection limit of adulteration was as low as 5 %, and even much lower than 5 % for most kinds of camellia seed oil, which was lower than those measured by other methods. All the results indicated that this simple, accurate and rapid method can also be recommended for the authentication of olive oil with some modification.