Improving the fatty acid composition of soybean oil

Efforts to improve the composition of soybean oil by breeding the beans for low linolenic acid in the oil have continued since 1968. This paper reports recent work using hybrid crosses and induced mutations. No lines are yet available that contain oil having less than 3% linolenic acid. Journal Paper No. J-11466 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 2475.     

The linolenic acid content of peanut oil

Oils prepared from eight peanut cultivars grown in four locations were analyzed for linolenic acid (18:3) content by gas liquid chromatography. Columns packed with either OV 225 or butanediol succinate provided excellent separation of 18:3 from major fatty acids and from trace constituents exhibiting retention times suggestive of 19:0 and 19:1. Average linolenic acid values for cultivars ranged between 0.03 and 0.13 weight percent of total fatty acids.     

Developmental changes in fatty acid composition of oil in kernel fractions of corn (Zea mays L.)

Gas liquid chromatography was used to determine the change in fatty acid composition of oil from three kernel fractions (pericarp, endosperm and germ) during kernel maturation of four inbred lines of corn. Inbred lines were sibpollinated, and sampling of ears began six days after pollination (DAP) and continued at three day intervals until 33 DAP and then at weekly intervals until 54 DAP. Proportion of palmitic acid in the pericarp oil rapidly decreased between 6 and 12 DAP while oleic and linoleic acids increased during the same period. Changes in fatty acid composition of oil from the endosperm during kernel maturation were erratic and no consistent trends were evident. In the germ oil, palmitic and linolenic acid proportions decreased during kernel maturation, while oleic acid decreased and linoleic acid increased during kernel maturation for three of the four inbred lines. By about 24 to 27 DAP, the fatty acid composition of oil in the mature kernel was established. Since kernel fractions are of different genetic origin, a study of developmental changes in lipid classes or in fatty acid composition of oil should be limited within kernel fractions that have a similar genetic constitution. Approved as Journal Series Paper No. 723, University of Georgia, College of Agriculture Experiment Stations.     

Oxidative stability of purified canola oil triacylglycerols with altered fatty acid compositions as affected by triacylglycerol composition and structure

Canola oil triacylglycerols from genetically modified canola lines (InterMountain Canola Co., Cinnaminson, NJ) have been evaluated for their photooxidative and autoxidative stabilities, as influenced by their fatty acid compositions and their triacylglycerol compositions and structures. Purified canola oil triacylglycerols were oxidized in duplicate in fluorescent light at 25°C and in the dark at 60°C under oxygen, and their oxidative deterioration with time was monitored by determining colorimetric peroxide values. Also monitored with time, oxidation products were determined by reversed-phase high-performance liquid chromatography with ultraviolet absorbance detection. Total volatiles, generated by thermal decomposition of the oxidized triacylglycerols, were quantitated by static-head-space gas chromatography. These experimental parameters were statistically correlated with predicted oxidizability, fatty acid composition, position of fatty acids on glycerol carbons and triacylglycerol composition. Oxidative deterioration of canola triacylglycerols correlated negatively with oleic acid composition, with oleic acid content at carbon 2 and with trioleoylglycerol content of the oil. Deterioration was positively correlated with the amount of linolenic acid on nonspecific locations on glycerol carbons 1,2 and 3, the amount of linoleic acid on glycerol carbon 2 and withsn-oleoyllinoleoyllinolenoyl glycerol content. Differences in character or quantity of volatile product and triacylglycerol hydroperoxides were low, whether generated during autoxidation or photooxidation of the canola triacylglycerols. Presented at the joint meeting of the American and Japan Oil Chemists' Societies, April 25–28, 1993, Anaheim, California.     

Effect of altered fatty acid composition on soybean oil stability

During the last 15 years, hybridization and induced mutation breeding of soybeans have been successful in producing an altered fatty acid composition in the extracted oil. The objective of those investigations was to produce a low-linolenic acid soybena oil. Crude oils extracted from the seeds of three such genotypes were processed in laboratory simulations of commercial procedures to finished deodorized oils. Analysis of the fatty acid composition of the three oils showed the linolenic acid content to be 3.3%, 4.2% and 4.8%. The stability of these finished oils was compared to that of oil from a soybean variety having a linolenic acid content of 7.7% and of a commercial hydrogenated-winterized soybean oil (3.0% linolenic acid). Test and control oils were evaluated by a trained sensory panel initially, after accelerated storage at 60 C and during use at 190 C in room tests. Peroxide values were determined at the time of sensory evaluation. Results indicated there was no significant difference in flavor stability during storage between test and control oils. There was no significant difference, between the oils, in peroxide development during accelerated storage. Compared to control oils, the test oils had improved overall room odor intensity scores and lacked the fishy odors of non-hydrogenated soybean oil and the hydrogenated odors of commercial cooking oil. Presented at the AOCS meeting in Honolulu, HI in May 1986.     

Antioxygenic properties of molecularly distilled fractions of peanut oil

Summary 1. Samples of unhydrogenated and hydrogenated peanut oils, which had been refined, bleached, and deodorized, were separated into two comparable series of fractions by molecular distillation. The various fractions were analyzed for tocopherols (and related chromogens) by the method of Furter and Meyer, and stability tests by the Swift method were made on the larger distilled fractions. 2. Molecular distillation at 140°, 160°, and 180° C. yielded antioxidant concentrates (presumably of tocopherols) from each oil; distillation at 240° yielded fractions almost devoid of antioxygenic substances. 3. In the unhydrogenated and hydrogenated oils, approximately 40 percent and 20 percent, respectively, of the chromogenic substances reacting in the Furter-Meyer tests were undistillable and remained in the residue comprising 10 percent of the original oil. 4. Evidence was found of the presence of distillable antioxidants other than tocopherols, which either do not respond to the Furter-Meyer test or else respond to it weakly, in proportion to their antioxygenic activity. 5. Hydrogenation of the oil had no appreciable effect on the activity of its distillable antioxidants. 6. The progressively increased addition of tocopherol-rich concentrates to fractions almost devoid of antioxidants resulted in first decreasing and then increasing the initial rate of peroxide formation in the stability tests. 7. In the case of the unhydrogenated oil, there was an optimum level of antioxidant concentration above which the addition of these substances had no stabilizing action. However, hydrogenated oil showed an increase in stability with the addition of antioxidants up to the highest level to which the concentration of the latter was carried (approximately 0.15 percent, calculated asa-tocopherol). Presented before the American Oil Chemists’ Society Meeting, New Orleans, Louisiana, May 12 to 14, 1943.     

The fatty acid composition of cottonseed oil at various stages of solvent extraction

The variation in the fatty acid composition of the glyceride portion of cottonseed oil at various stages of solvent extraction has been investigated. Prime cottonseed meats were flaked and extracted in glassware rate extraction apparatus, using commercial hexane up to different degrees of extractions. The fatty acid composition of cottonseed oil obtained after extracting the flakes to different residual oil contents was determined by gas-liquid partition chromatography. No difference was found.     

Variability for oil and fatty acid composition in castorbean varieties

Thirty-six castorbean varieties were surveyed for oil and fatty acid composition, in order to determine variability of these seed compounds. A large variability of seed oil percentage was observed, ranging from 39.6 to 59.5%. Concerning the fatty acids, little variability was observed for ricinoleic acid, which was the most abundant in the oil, ranging from 83.65 to 90.00%. The other fatty acids appeared in small concentrations and showed a small range: 0.87 to 2.35, 0.68 to 1.84, 2.96 to 5.64, 3.19 to 5.98, and 0.34 to 0.91%, for palmitic, stearic, oleic, linoleic, and linolenic acid, respectively. Non-significant correlations were observed between fatty acids and seed oil percentage. However, significant correlations were observed among fatty acid concentrations: positive and negative ones. These significant correlations could be associated with the biosynthetic pathways of the fatty acids, which are not fully elucidated. They suggest, however, that selection for a particular fatty acid will tend to increase those positively correlated, and decrease those negative ones. Selection and plant breeding techniques could then be applied to modify the oil content of the castorbean seeds, considering the variability observed. For the fatty acid composition, however, the variability was not large enough to make substantial changes in their concentrations by selection procedures. More varieties should be surveyed to find out if such variability is available.     

桂花果实油脂脂肪酸组成的GC-MS分析

采用索氏提取法提取桂花果实核仁中的油脂,通过GC-MS分析油脂中脂肪酸的组成及含量。结果显示,桂花果实核仁油脂中鉴定9种脂肪酸,主要包含油酸(39.04%)、亚油酸(33.15%)、棕榈酸(10.31%)、硬脂酸(3.80%)、9,12-十八二烯酸(4.62%)和γ-亚麻酸(6.44%)。其中油酸和亚油酸等不饱和脂肪酸含量高达83.25%。桂花果实核仁中油脂的不饱和脂肪酸含量高,具有良好的应用前景。     

Correlation of stability with fatty acid composition of hydrogenated vegetable oil

Cottonseed, peanut, and linseed oils were hydrogenated under selective and non-selective conditions and samples were withdrawn periodically for determination of their fatty acid composition, keeping quality, and other characteristics. The results were submitted to graphical and statistical analysis from which the following conclusions were drawn.

1. When cottonseed or peanut oil is hydrogenated either under selective or non-selective conditions, the change in the reciprocal of the keeping quality, as measured by the active oxygen method, is proportional to the change in linolein content up to the point of disappearance of linolein.
2. After all linoleic acid has disappeared, the change in keeping quality is proportional to the change in olein content.
3. When linseed oil is hydrogenated under selective conditions, the change in the reciprocal of the keeping quality is proportional to the change in the linolenin content up to the point of disappearance of the linolenin.

     

Lipid and fatty acid composition of different fractions from rat urinary transitional epithelium

The phospholipid composition of rat urinary transitional epithelium (TE) and the fatty acid composition of microsomal, mitochondrial, cytosolic, and plasma membrane (PM) subcellular fractions were investigated. PM marker enzymes and electron microscopy analysis were used to characterize the PM fraction, which showed a distinctive lipid composition compared to the general profile of PM from different sources. The levels of cholesterol and sphingomyelin were not enriched in the PM fraction; on the other hand, the increased amounts of glycosphingolipids and phosphatidylserine, and the decreased level of phosphatidylcholine followed the general features of a PM profile. This differential PM lipid composition may reflect the unique morphology of this mammal TE, consisting of concave plaques with an asymmetrical membrane unit. The distribution of the double bond across the PM indicated a higher unsaturation of the inner relative to the outer part of the PM hemileaflet. In addition, the presence of 20∶3n−9 nonessential fatty acid in a normal TE may represent a characteristic fatty acid metabolism of this epithelium. The authors wish to dedicate this work to the memory of the late Professors Benito Monis, who participated in the generation of this research and whose working hypothesis remains a source of fruitful inspiration.     

Relation between fatty acid composition and iodine value of cottonseed oil

Summary The regularity in the increase in linoleic, and in the decrease in oleic and saturated acids with increase in iodine value of cottonseed oils has been shown by obtaining the regression equation for the glyceride of each acid on the iodine value by use of the compositional data on 48 samples of oil ranging from 89.8 to 117.0 in iodine value. These equations offer a ready means of approximating the fatty acid composition of cottonseed oils from their iodine values. Such approximations may prove useful in the segregation of oils for different end uses. The compositional pattern of cottonseed oils is compared with those reported in the literature for soybean and linseed oils. Report of a study made under the Research and Marketing Act of 1946. Presented at the sring meeting of the American Oil Chemists' Society, New Orleans, La., May 1–3, 1951. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agricuture.     

The fatty acid composition of clothes soil

Summary Organic soil that had gradually accumulated on cotton garments and was unremovable by normal washing procedures was analyzed for free and combined fatty acids by gas-liquid chromatography. The fatty acid composition of this material was similar to sebum and hair fat and was remarkably uniform although from several different sources and geographical locations. The predominant fatty acids were C₁₅, C₁₆, and C₁₈ straight-chain acids. More than 30% of the total fatty acid was palmitic acid. The amount of oleic acid was considerably less than is reported for hair and skin fat. No linoleic acid or linolenic acid was detected. The small amount of unsaturated acids is probably the result of their oxidation to polymers and other oxidation products. The amount of free fatty acids was very small because they were converted to insoluble heavy metal soaps. Most of the combined fatty acids were present as esters,i.e., triglycerides.     

The fatty acid composition of some entomophthoraceae

Lipids extracted fromConidiobolus denaesporus Drechsl. were found to contain three branched-chain fatty acids, which together comprised about 35% of the total fatty acids of the fungus. The branchedchain acids were identified by gas-liquid chromatography, infrared and mass spectroscopy as 12-methyl tridecanoic, 12-methyl tetradecanoic, and 14-methyl pentadecanoic acids respectively. Then-saturated acids comprise C12, C13, C14, C16, and C18. Then C16,n C18, andn C20 unsaturated acids were also found. The occurrence of 15.2% of myristic acid and of 8.9% of eicosatetraenoic acid provides a further distinctive feature of the lipids ofConidiobolus denaesporus. Contribution No. 94.     

Improving the fatty acid composition of corn oil by using germplasm introgression

The general public has shown increasing interest in consuming oils that are beneficial to health. Thus, oil from corn (Zea mays L.), along with most major edible oils, has been the target of genetic alterations to improve the fatty acid composition. The fatty acid profile goals vary, depending upon the intended use for the oil. We have targeted the development of corn oil with 1) low total saturated fatty acids, 2) high total saturated fatty acids, and 3) mid‐oleic acid, in each case via two different sources: exotic germplasm identified through an international program to broaden the corn germplasm base and introgression of a wild, grassy relative of corn, Tripsacum (Tripsacum dactaloides L). We have been successful at identifying corn lines with each of the noted traits.     

Effect of controlled temperature environments on oil content and on fatty acid composition of corn oil

Total oil content and fatty acid composition of germ and endosperm oil were determined on grain from three inbred lines and one variety of corn (Zea mays L.) grown in four phytotron environments and one standard greenhouse environment during seed maturation. Pronounced differences occurred with reversals for relative percentages of oleic and linoleic acids of germ oil for one inbred line and for the variety. Comparative trends were generally less pronounced for two of the inbred lines. Differences among environments were less evident for palmitic, stearic, and linolenic acids of germ oil and for the fatty acids of the endosperm oil. Total oil was lowest for two inbred lines and the variety grown in the high temperature environment (30 C day/26 C night). The magnitude of temperature effects on oil content and oil composition varied among the four corn genotypes. Journal article 3961 of the North Carolina State University Agricultural Experiment Station. ARS, USDA.     

The control of fatty acid composition in glycerolipids

The continued suggestion that the ratio of saturated to unsaturated acids in the diet can influence the general health of a mammal is still not easily explained at a biochemical level. Studies on the metabolism of glycerophosphatides show that the enzymes involved appear to differ in the degree of selectivity toward substrates with different amounts of unsaturation. In general, each individual acid will have its own characteristic metabolic fate. The acyl-CoA:acyl-GPC acyltransferases have a marked specificity for both the position to be acylated and the particular acyl-CoA involved. In some cases, the observed distributions of fatty acids in naturally occurring lecithins and triglycerides are similar to the distributions predicted from in vitro studies of the acyltransferase enzymes. Other enzymatic steps, such as acid activation and N-methylation, can also be shown to influence the fatty acid composition of the glycerolipids. The relative importance of these metabolic processes must now be determined.     

The fatty acid composition of various cruciferous seeds

Seeds from 26 Cruciferae species in 7 genera have been investigated for fat content and fatty acid composition of the oil. The GLC retention data have been verified by mass spectrometry. The oil from Cardamine graeca contained 54% of cis-15-tetracosenoic acid; it is the highest content of this acid so far reported in any seed fat.     

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

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