The α,β-distribution of oleic,linoleic and linolenic acids in cruciferae seed triglycerides

Correlation studies on lipolysis data from 24 species of Cruciferae seed triglycerides have revealed very regular positional distribution patterns for oleic, linoleic and linolenic acids. When the ratio % 18:1 in β-position/% 18:1 in total triglycerides for each species is plotted vs. the content of Category I acids (16:0, 18:0, plus all C₂₀, C₂₂ and C₂₄ acids) in the total triglycerides, a smooth curve is obtained. Application of suitable statistical procedures yields a best-fitting curve, from which an equation expressing the % 18:1 in the β-position as a function of the fatty acid composition of the total triglycerides can be derived. The % 18:1 in the α-position is then readily calculated by difference. Similar distinctive relationships have also been developed for linoleic and linolenic acids. Comparison of calculated and experimental results shows that the relationships developed here are considerably more accurate than the previous Gunstone-Mattson and Evans hypotheses for estimating the α,β-distributions of 18:1, 18:2 and 18:3 in Cruciferae seed triglycerides. Presented in part at the AOCS meeting in San Francisco, California, April 1969.     

Changes in the structure of soybean triglycerides during maturation

Soybeans of the Hawkeye variety were picked at eleven periods from 30 to 111 days after flowering and extracted with chloroform-methanol. The triglyceride fraction of five pickings, selected 35 to 91 days after flowering (when synthesis of lipid was most active), were isolated by silicic acid thin layer chromatography (TLC) and species composition determined using argentation TLC and lipase hydrolysis. The triglyceride content of the total lipid increased from 6.5% at 30 days after flowering to 85% in the mature bean (111 days). The major changes in fatty acid composition of the triglycerides occurred during the first 52 days after flowering. During this period linolenic acid decreased from 34.2% to 11.7%, the percentages of linoleic and oleic acids increased, stearic remained fairly constant and palmitic decreased slightly. Large quantitative changes occurred in the molecular species of the triglycerides of the bean during maturation; some triglycerides containing linolenic acid could not be detected approximately 66 days after flowering. Although changes occurred in the percentage and amount of each triglyceride species, the positional distribution of fatty acids remained virtually unchanged throughout maturation. Linolenic acid was distributed fairly uniformly between the β-position and the α-positions, linoleate favored esterification in the β-position, and oleate the α-positions. Most of the stearic and palmitic acids were esterified in the α-positions. The consistency of the positional arrangement of the fatty acids indicated that the mode of glyceride synthesis was established very early during maturation and molecular species composition was controlled by the fatty acids available for synthesis.     

Fatty acid positional distribution in egg yolk triglycerides from various avain species

The fatty acid composition and distribution in egg yolk triglycerides and phosphatides from the turkey, duck, prairie chicken, bobwhite quail, Japanese quail, and inbred-hybrid and midget mutant hens were determined after all species had been fed diets of similar fat and fatty acid content for 90 days. Total volk lipids were composed of ca. two-thirds neutral lipids and one-third polar lipids. The predominant fatty acids were palmitic and stearic. There were statistically significant differences in the my ristic, palmitic, palmitoleic, linoleic, and linolenic acids in the yolk triglycerides and in the proportion of 16∶1, 18∶0, 18∶2, arachidonic, docosanoic, docosahexaenoic, and tetracosanoic acids in the phosphatides among the various species. Linoleic acid predominantly was linked at the 2-position in the yolk triglycerides followed by the 20∶4 acid. The 18∶1 acid also was found preferentially at the 2-position. There was a low level of 18∶2 in the yolk triglycerides and phosphatides from the duck and an especially high level of 20∶4 acid in the phosphatides. The triglycerides in the species studied have essentially the same distribution of fatty acids in the 2-position. In all the species, the affinity for the fatty acids at the 2-position is in the following order: 18∶2=20∶4>18∶1 =18∶3>18∶0=16∶1>14∶0>16∶0 Differences observed among the various genera did not appear to follow taxonomic boundaries. The duck has an efficient system for converting 18∶2 into 20∶4 by elongation and desaturation. The prairie chicken apparently has a high requirement for 18∶2 but an inadequate system for its conversion into 20∶4.     

Positional distribution of the fatty acids in the triglycerides of mango (Mangifera indica) kernel fat

Triglycerides of mango seed kernel fat contain, depending on the variety, 32.4–44.0% of stearic acid and 43.7–54.5% of oleic acid. Palmitic and linoleic acids represent, respectively, 5.9–9.1% and 3.6–6.7% of the fatty acids. The triglycerides also contain minor amounts of arachidic and linolenic acids. Palmitic, stearic and arachidic acids were almost exclusively distributed among thesn-1-andsn-3-positions. Oleic acid represented 85–89% of the fatty acids at thesn-2-position. Oleic acid at thesn-1- andsn-3-positions showed a preference for thesn-1-position. Linoleic acid was mainly esterified at thesn-2-position. The amounts of saturated fatty acids, i.e., palmitic and stearic acids, and of oleic acid, at thesn-1- and sn-3-positions, were linearly related to their respective contents in the total triglycerides.     

Composition and crystallization of milk fat fractions

Milk fat was fractionated by solvent (acetone) fractionation and dry fractionation. Based on their fatty acid and acyl-carbon profiles, the fractions could be divided into three main groups: high-melting triglycerides (HMT), middle-melting triglycerides (MMT), and low-melting triglycerides (LMT). HMT fractions were enriched in long-chain fatty acids, and reduced in short-chain fatty acids and unsaturated fatty acids. The MMT fractions were enriched in long-chain fatty acids, and reduced in unsaturated fatty acids. The LMT fractions were reduced in long-chain fatty acids, and enriched in short-chain fatty acids and unsaturated fatty acids. Crystallization of these fractions was studied by differential scanning calorimetry and X-ray diffraction techniques. In this study, the stable crystal form appeared to be the β′-form for all fractions. At sufficiently low temperature (different for each fraction), the β′-form is preceded by crystallization in the metastable α-form. An important difference between the fractions is the rate of crystallization in the β′-form, which proceeds at a much lower rate for the lower-melting fat fractions than for the higher-melting fat fractions. This may be due to the much lower affinity for crystallization of the lower-melting fractions, due to the less favorable molecular geometry for packing in the β′-crystal lattice.     

Application of gas-liquid partition chromatography to the quantitative estimation of monoglycerides

Summary A procedure has been developed for the quantitative estimation of monoglycerides in terms of their constituent fatty acids. The monoglyceride mixture is mesylated with mesyl chloride in the presence of pyridine, and the resulting dimesyl derivatives are converted to allyl esters of the constituent fatty acids by treatment with sodium iodide in anhydrous acetone at 100°C. The allyl esters are then analyzed quantitatively by gas-liquid partition chromatography at 240°C. on a column of Apiezon M—Celite. Both α- and β-monoglycerides are quantitatively converted to allyl esters by this procedure. β-Monoglycerides in a mixture of α- and β-isomers may be determined separately after removal of the α-isomers by oxidation with periodic acid. The analytical procedure is also applicable to monoglycerides in the presence of free fatty acids, diglycerides, and triglycerides. Issued as N.R.C. No. 5438. Presented at the 32nd fall meeting, American Oil Chemists' Society, Chicago, Ill., October 20–22, 1958. National Research Council Postdoctorate Fellow, 1956–1958.     

Fatty acids of bovine milk glycolipids and phospholipids and their specific distribution in the diacylglycerophospholipids

Milk lipids were fractionated by silicic acid column chromatography and preparative thinlayer chromatography (TLC). Ceramide monohexoside (CMH), ceramide dihexoside (CDH), phosphatidyl ethanolamine (PE), phosphatidyl choline (PC), phosphatidyl serine (PS), and sphingomyelin (Sph) were isolated, and the purity of each was checked by infrared spectroscopy and TLC. The diacylphospholipids were hydrolyzed with phospholipase A and the products separated by TLC. Fatty acid methyl esters were prepared from the various fractions and analyzed by gas chromatography. The glycolipids, CMH and CDH, and Sph contained large amounts of long-chain saturated fatty acids, especially C_22:0, C_23:0, and C_24:0, PE, PS, and PC contained C₁₀-C₂₂ normal and branched-chain saturated fatty acids, and C₁₅-C₂₀ unsaturated fatty acids (mainly monoenes). The distributions of saturated acids between the α′- and β-positions were respectively: PE, 46 and 11%; PS, 65 and 19%; and PC, 72 and 53%. PC was exceptional in that there was 10.8% myristic acid in the β-position and only 5.6% in the α′-position. PE and PS were similar in composition except that in PE oleic acid was evenly distributed, and in PS was largely in the β-position. In general, PC was much more saturated than PE or PS, and there was no overall pattern governing the specific distribution of the fatty acids in the three diacylphospholipids. Comparison with PC from other bovine tissues and from egg lecithin showed that fatty acids are located much less specifically in milk phospholipids than in PC from other sources. Presented at the AOCS Meeting, Houston, Texas, April, 1965.     

Composition of fatty acids and structure of triglycerides in medium and low erucic acid rapeseed

Total triglycerides in medium (MEAR) and low (LEAR) erucic acid cultivars of rapeseed were fractionated by argentation chromatography into twelve and ten fractions, respectively. Gas liquid chromatography of the fatty acids in the triglyceride fractions and their 2-monoglycerides was used to evaluate the structural characteristics of the individual fractions. Fractionation occurred on the basis of degree of unsaturation, molecular weight and positional characteristics. The most mobile fractions contained 34–50% of saturated fatty acids while the less mobile had 59–65% of polyunsaturated fatty acids. In the medium erucic acid oil, long chain fatty acids (C20–C22) were found in all fractions, but four fractions of low erucic acid oil were essentially free of long chain acids. Two of these fractions in the latter oil, which represented 44% of the total triglycerides, were glycerol trioleate and dioleoyllinoleoylglycerol. The majority of the 2-positions were occupied by unsaturated C18 fatty acids, generally in the order of linoleic ≥linolenic> oleic acids. The saturated and long chain fatty acids occurred predominantly in the 1-and 3-positions. The various fractions of medium and low erucic acid oils were similar in structural composition except that eicosenoic and erucic acids substituted for oleic acid in some external positions. Erucic acid did not appear to substitute directly for oleic acid in the 2-position.     

Thermal acclimation and dietary lipids alter the composition,but not fluidity,of trout sperm plasma membrane

The effect of a long-term adaptation of rainbow trout to 8 and 18°C combined with a corn oil-or a fish oil-supplemented diet on the characteristics of the spermatozoan plasma membrane was investigated. The experiment lasted up to 22 mon during which spermatozoa were collected from the mature males. Spermatozoan plasma membranes were isolated by nitrogen cavitation, and the cholesterol content, phospholipid composition and fatty acid pattern were investigated. Membrane viscosity was assessed on whole cells by electron spin resonance using spin-labeled phospholipids. Neither diet nor rearing temperature influenced the cholesterol content of the plasma membrane nor the phospholipid class distribution. The rearing temperature of the broodstock only slightly affected the phospholipid fatty acids. A minor decrease in 18∶0 and increase in monounsaturated fatty acids was observed for the cold-adapted fish. These modifications were not sufficient to affect membrane fluidity, and we conclude that trout spermatozoa do not display any homeoviscous adaptations in these conditions. On the contrary, the dietary fatty acid intake greatly modified the fatty acid profile of plasma membrane phospholipids. The fish oil-fed trout displayed a much higher n−3/n−6 fatty acid ratio than did the corn oil-fed ones, but the 22∶6n−3 levels remained unchanged. Modifications in plasma membrane composition by the diet were obtained although neither of the two diets was deficient in essential fatty acids. The enrichment in n−3 fatty acids, however, did not affect plasma membrane fluidity which was unchanged by the diets.     

Composition and positional distribution of fatty acids in phospholipids isolated from pork muscle tissues

The composition and positional distribution of fatty acids in phospholipids isolated from four locations of a hog carcass is presented. Variations in fatty acid composition of phospholipids were found depending upon the location in the carcass. The total unsaturated fatty acid content averaged 34.3 mole % for lecithin, 52.5 mole % for phosphatidylethanolamine, 40.3 mole % for phosphatidylserine and 41.3 mole % in sphingomyelin. The cephalins had a much higher percentage of polyunsaturated fatty acids than lecithin. The chief saturated fatty acid in lecithin and sphingomyelin was palmitic and in cephalins it was stearic. A snake venom enzyme preparation(Crotalus adamanteus) hydrolyzed primarily unsaturated fatty acids in phosphoglycerides and the higher the percentage of unsaturation within the fatty acid the higher percentage of hydrolysis occurred. The unsaturated fatty acids were found chiefly at the theβ-position and the saturated fatty acids at thea-position in the phosphoglycerides. Michigan State Agricultural Experiment Station Publication No. 3389. Supported by the U.S. Public Health Service Research Grant No. GM 08801-03.     

Influence of partially hydrogenated vegetable and marine oils on lipid metabolism in rat liver and heart

Partially hydrogenated marine oils containing 18∶1-, 20∶1- and 22∶1-isomers and partially hydrogenated peanut oil containing 18∶1-isomers were fed as 24–28 wt % of the diet with or without supplement of linoleic acid. Reference groups were fed peanut, soybean, or rapeseed oils with low or high erucic acid content. Dietary monoene isomers reduced the conversion of linoleic acid into arachidonic acid and the deposition of the latter in liver and heart phosphatidylcholine. This effect was more pronounced for the partially hydrogenated marine oils than for the partially hydrogenated peanut oil. The content oftrans fatty acids in liver phospholipids was similar in groups fed partially hydrogenated fats. The distribution of various phospholipids in heart and liver was unaffected by the dietary fat. The decrease in deposition of arachidonic acid in rats fed partially hydrogenated marine oils was shown in vitro to be a consequence of lower Δ6-desaturase activity rather than an increase in the peroxisomal β-oxidation of arachidonic acid. The lower amounts of arachidonic acid deposited may be a result of competition in the Δ6-desaturation not only from the C22-and C20-monoenoic fatty acids originally present in the partially hydrogenated marine oil, but also from C18- and C16-monoenes produced by peroxisomal β-oxidation of the long-chain fatty acids. Part of this work was presented at the ISF-AOCS Congress, New York City, 1980.     

Positional distribution of the fatty acids in the triglycerides of the oil of some african peanut varieties

The distribution of fatty acids between the sn-1-, sn-2- and sn-3-positions of the triglycerides from the oils of eight African peanut varieties has been determined. The saturated fatty acids and eicosenoic acid occur almost exclusively at the sn-1- and sn-3-positions. The sn-1-position contained slightly more palmitic acid than the sn-3-position. The fatty acids with a chain length exceeding 18 carbons were preferentially incorporated in the sn-3-position. Linoleic acid was preferentially esterified at the sn-2-position, whereas oleic acid was equally distributed among the three positions. The amount of the saturated fatty acids, i.e., palmitic and stearic acid, and of oleic acid and linoleic acid incorporated in the sn-1-, sn-2-and sn-3-position, were each linearly related to their respective content in the triglycerides.     

Polymorphic stability of some shortenings as influenced by the fatty acid and glyceride composition of the solid phase

A number of North American vegetable and animal fat shortenings, which had been analyzed previously for their physical and textural characteristics, were analyzed also for their chemical composition. The fatty acid and triglyceride composition of the solids were calculated by analyzing the composition of the original product and the liquid phase, and by determination of the solid fat content (SFC) of the fat. The solids were also isolated by isopropanol (IP) separation, and the high melting glycerides (HMG) by acetone crystallization at 15°C. There was not much difference in total saturates andtrans content between vegetable and animal fat shortenings. Changing formulations from soy-palm to soy-cottonseed does not change the total saturates plustrans content. The solids of the vegetable shortenings in the β form contained about 20% of 16:0, those in the β′ form 30% or more. The animal fat shortenings were mainly in the β form, their solids contained 30% or more of 16:0. C54 triglyceride content of the solids of β vegetable shortenings (calculated and IP-separated) was >45%, that of all animal fats was <25%. Solids of animal fat shortenings contain high levels of C52. The C54 triglycerides are β-tending and should be kept low in vegetable shortening. In the HMG the C54 should not exceed 30%. This can only be achieved by incorporation of a β′ hard fat, preferably palm hard fat. Animal fat, especially lard, crystallizes in the β form because the palmitic acid in the glyceride molecule is located in the 2-position, whereas those of vegetable fats are in the 1- and 3-position.     

Positional distribution of fatty acids in triglycerides from milk of several species of mammals

Milk triglycerides from the echidna, koala, Tammar wallaby, guinea pig, dog, cat, Weddell seal, horse, pig and cow were subjected to fatty acid and stereospecific analysis to determine the positional distribution of the fatty acids in the triglycerides. The samples presented a wide range of fatty acids, most of which varied in content among species. The compositions of the acids at the 3 positions also varied among species, reflecting the content of these acids in the triglycerides. However, there was a general similarity in fatty acid positional distribution patterns for all the species with the exception of the echidna. The echidna exhibited a completely different fatty acid positional distribution pattern. The saturated acids were preferentially esterified at thesn-1-position whereas the unsaturated acids were selectively esterified at thesn-2-position. The triglyceride carbon number distribution of milk from the above species (with the exception of the Weddell seal) was determined by gas liquid chromatography and compared to that predicted by the 1-random-2-random-3-random fatty acid distribution hypothesis. Agreement was excellent between observed and predicted composition for echidna, koala, Tammar wallaby, guinea pig and pig milk, and agreement was reasonable for dog, cat, horse and cow milk. Results are discussed in relation to biochemical mechanisms.     

Glyceride structure ofCardamine impatiens L. Seed oil

A group of unusual triglycerides, in which one of the acyl groups is a vicinal dihydroxy acid with one of the hydroxyl groups acetylated, has been isolated fromCardamine impatiens L. (Cruciferae) seed oil. Hydrolysis of these triglycerides with castor bean lipase facilitated isolation and identification of a mixture of C₁₈, C₂₀, C₂₂, and C₂₄ hydroxy acetoxy fatty acids. Pancreatic lipase hydrolysis data revealed that these monoacetylated dihydroxy acid residues are esterified exclusively with one of the α-positions of the glycerol moiety. The remaining acyl groups are comprised of ordinary C₁₈ unsaturated acids (which occupy 98% of the β-position), palmitic acid, and C₂₀, C₂₂, and C₂₄ monoenoic fatty acids. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Quantitative effects of dietary polyunsaturated fats on the composition of fatty acids in rat tissues

A method combining data on fatty acid composition into subsets is used to illustrate general relative competitive selectivities in the metabolic and transport events that maintain fatty acid compositions in tissue lipids and to minimize differences among tissues or species in the amount of individual fatty acids. Fatty acid compositions of triglycerides and phospholipids in several tissues of the rat were maintained with simple relationships between the exogenous n−3 and n−6 dietary polyunsaturated fatty acids and the endogenous n−7 and n−9 types of fatty acid. The general pattern of fatty acids in triglycerides was similar for liver, plasma and adipose tissue, averaging about 30% as saturated acids, 67% as 16- and 18-carbon unsaturated acids and only about 2% as 20- and 22-carbon highly unsaturated acids. The tissues maintained a linear relationship between the amount of 18-carbon polyunsaturated fatty acids in the diet and in the tissue triglycerides, with the proportionality constant for 18∶3n−3 being 60% of that for 18∶2n−6. The total phospholipids of liver, plasma and red blood cells maintained about 45% of the fatty acids in the form of saturated fatty acids and 20–30% as 20- and 22-carbon highly unsaturated fatty acids irrespective of very different proportions of n−3, n−6 and n−9 types of fatty acids. In all three tissues, the 20-carbon highly unsaturated fatty acids of the n−3, n−6 and n−9 type were maintained in a competitive hyperbolic relationship with apparent EC₅₀ values for dietary 18∶2n−6 and 18∶3n−3 near 0.1% of dietary calories. The consistent quantitative relationships described in this study illustrate an underlying principle of competition among fatty acids for a limited number of esterification sites. This approach may be useful in predicting the influence of diet upon tissue levels of the substrates and antagonists of eicosanoid biosynthesis.     

Distribution of dietary octadecenoate isomers at the 1- and 2-positions of hepatoma and liver phospholipids

Phosphatidylcholines and phosphatidylethanolamines were isolated from hepatoma 7288CTC, normal liver, and host liver of rats fed one of the following diets: fat-free diet; fat-free diet supplemented with safflower oil, safflower oil fatty acids, or partially hydrogenated safflower oil fatty acids; and commercial chow. Thecis andtrans octadecenoate fatty acids were isolated from the 1- and 2-positions of both phosphoglycerides and analyzed quantitatively for chain positional isomers. Octadecenoates from hepatoma and liver phosphoglycerides of animals fed fat-free or natural fatsupplemented diets contained almost exclusively twocis isomers: oleic and vaccenic acids. Oleic acid predominated in the 2-position octadecenoates of both phosphoglycerides from hepatoma and liver. In contrast, vaccenic acid predominated in the 1-position of normal liver phosphatidylcholine and, to a lesser extent, phosphatidylethanolamine. Host liver and hepatoma exhibited a shift to a higher percentage of oleic acid at the 1-position. Dietarytrans fatty acids were incorporated predominately in the 1-position of both phosphoglycerides of hepatoma and liver. Except for thecis Δ10 octadecenoate isomer, all of the unnatural dietarycis isomers between Δ8 and Δ14 were incorporated into the 1-position of the phospholipids, while the unnaturalcis octadecenoates at the 2-position consisted primarily of the Δ12 isomer. Hepatoma phosphoglycerides contained higher percentages of thetrans Δ10 isomer that was nearly excluded from the 1-position of the two liver phosphoglycerides. All the othertrans octadecenoate isomers were incorporated into the 1-position of both phosphoglycerides, but the small amount oftrans fatty acids incorporated into the 2-position of liver and hepatoma phosphatidylcholine consisted of four isomers, Δ9 to Δ12, including the Δ10 isomer. Phosphatidylethanolamine exhibited a similar distribution, except for the presence of the Δ13 and Δ14 isomers at the 2-position. A combination of evidence suggests that the 1-position fatty acids in phosphatidylcholine and phosphatidylethanolamine are of similar origin. The octadecenoates at the 2-position of these two phosphoglycerides appear to be of the same origin in hepatoma but not in liver. It was also revealed that the 2-position of hepatoma phosphatidylcholine contained much higher percentages of palmitate than liver.     

Lipid composition of selected vegetable oils

This paper gives analytical data on the composition of 14 selected consumer-available liquid vegetable oils, including soybean, soybean-cottonseed blends, corn, safflower, peanut, olive and apricot kernel oils. Label information identified six samples as specially processed or refined and three samples as cold pressed with no preservative added; the labels of the remaining five samples did not mention processing. Data are given for fatty acid composition,trans content, location of the double bonds in the unsaturated fatty acids, percent conjugation, tocopherol content, fatty acid composition of the 2-poisition of the triglycerides, polyunsaturated to saturated fatty acid (P/S) ratio, and the ratio of α-tocopherol to polyunsaturated fatty acids (α-T/P). The ranges of values found were: conjugated unsaturation, 0.18–1.09%; α-tocopherol, 0.01–0.60 mg/gm; total tocopherol 0.14–1.52 mg/gm; P/S, 0.5–8.7; and α-TP, 0.03–2.26. The compositions of the fatty acids on the 2-position and on the 1,3-position of the triglycerides were compared with those calculated by the Evans’ hypothesis and found to agree well for all but olive and apricot kernel oils. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture, and does not imply its approval to the exclusion of other products that may also be suitable. Deceased     

Stereospecific analysis of maize triglycerides

This is the first report of stereospecific analyses of plant triglycerides isolated from seeds of distinct genotypes rather than from commerically refined oils. Triglycerides from six maize inbreds were analyzed. The strains exhibited a wide range of fatty acid compositions (palmitic acid 7.8–19.1%, oleic acid 17.0–43.0%, linoleic acid 41.6–68.3%). The distribution of the fatty acids among the 1, 2 and 3 positions of the triglycerides was clearly nonrandom for all six strains. At the 2 position of the triglycerides over 98% of the fatty acids were unsaturated. More plamitic and stearic acids were found in position 1 than in 3. The general fatty acid pattern of maize triglycerides was similar to that found in most animal triglycerides.     

Thermal oxidation of synthetic triglycerides I. composition of oxidized triglycerides

Tripalmitin, 1- and 2-lauryl dipalmitin and 1- and 2-oleyl dipalmitin were subjected to thermal oxidation at 200C in the presence of air for various lengths of time. The triglycerides showed a loss in weight, and an increase in carbonyl hydroxyl and acid values. The I.V. increased in the case of saturated triglycerides and decreased in the case of unsaturated triglycerides. Hydrolysis of the ester linkage between glycerol and fatty acid was found to occur during thermal oxidation of the type and position of the fatty acid in the triglyceride molecule. The fatty acids released from the triglyceride by hydrolysis were found either to be oxidized further to short chain fatty acids, or were oxygenated with the introduction of a carbonyl or hydroxyl group in the molecule. Moreover, the unsaturated fatty acid in the triglyceride molecule was found to be oxidized more readily than the saturated fatty acid. A hydroxy fatty acid with a carbon number of 13.5 on a diethylene glycol succinate column was isolated from oxidized tripalmitin and was also found to occur in the free fatty acid fraction of oxidized tripalmitin, 1-lauryl, 2–3 dipalmitin, and 1-oleyl, 2–3 dipalmitin. The presence of laurie or oleic acid in the 2-position of the triglyceride prevented the formation of this acid, which suggested that it is an oxidation product of palmitic acid. Portion of a thesis presented by J. G. Endres as partial fulfillment of the requirements for the degree of Ph.D. in food technology. Funds for partial support of these studies were made available by the National Institute of Health, Grant A-1671.