Showing papers on "Soybean oil published in 1978"

The synthesis of 2-(1-Pentenyl) furan and its relationship to the reversion flavor of soybean oil

Abstract: cis- andtrans-2-(2-Pentenyl)furans were synthesized and structures were confirmed by infrared, nuclear magnetic resonance and mass spectroscopy. Preliminary organoleptic evaluation of oil solutions of the compounds indicated that thecis isomer had a flavor threshold of ca. 0.25 ppm. with odor and flavor descriptions of beany, grassy and buttery at 0.50 ppm; and that thetrans isomer had a flavor threshold of ca. 0.50 ppm with odor and flavor descriptions of beany, grassy and buttery at 1 ppm and strong painty and metallic at 4 ppm. These compounds, if found in soybean oil through the autoxidation of linolenate, may contribute to the characteristic reversion flavor.

Flavor Score Correlation with Pentanal and Hexanal Contents of Vegetable Oil

Abstract: Samples of commercially processed soybean, cottonseed, and peanut oils were stored under controlled conditions then evaluated for flavor by a 20-member trained, experienced oil panel and for pentanal and hexanal contents by direct gas chromatography. The oils, which contained citric acid and/or antioxidants, were either aged from 0 to 16 days at 60 C or exposed to fluorescent light for 0 to 16 hr. The simple linear regressions of flavor score with the logarithm of pentanal or hexanal content in aged soybean oil gave correlation coefficients of −0.96 and −0.90, respectively; for cottonseed oil, −0.60 and −0.85; and for peanut oil −0.74 and −0.75. Addition of peroxide values to the linear regressions increased the correlation coefficients. Flavor scores of cottonseed and peanut oil can be predicted from pentanal and hexanal contents, but the technique is slightly more reliable for soybean oil based on the treatments used for these oils.

Comparative effects of saturated and unsaturated lipids on hepatic lipogenesis and cholesterogenesis in vivo in the meal-fed rat.

Abstract: The effects of saturated and unsaturated lipids on in vivo rates of hepatic lipogenesis and cholesterogenesis were compared. Lipogenic and cholesterogenic rates were determined in meal-fed rats either after feeding 1%, 5%, 10%, or 20% dietary corn oil or hydrogenated soybean oil for 14 days, or after intrgastric administration of fatty acyl ethyl esters (18:0, 18:1, or 18:2) for 1 and 3 days. Dietary hydrogenated soybean oil was not absorbed, whereas dietary corn oil and the intragastrically administered fatty acyl ethyl esters were well absorbed. Fatty acid synthesis measured from 3H2O and [14C] alanine was inversely correlated with unsaturated dietary fat content, but was unchanged by saturated dietary fat. A single daily administration of 18:0, 18:1, or 18:2 was ineffective in altering lipogenic rates. However, fatty acid synthesis was decreased by three consecutive daily doses of 18:1 or 18:2 (5 g/kg), but not by 18:0. Hepatic rates of cholesterogenesis from 3H2O and [14C] alanine were markedly enhanced by the administration of 10% or 20% saturated dietary fat. Feeding 1%, 5%, or 10% corn oil diets did not have an effect on cholesterogenesis. The 20% corn oil diet reduced the rate of conversion of [14C]anine into cholesterol while the rate of conversion of 3H2O remained unchanged. Neither the 1 day not 3 day oral administration of 18:0 or 18:1 had any effect on cholesterol synthesis; thereas the administration of 18:2 increased the conversion of [14C] alanine into cholesterol by 30% but did not after the rates of cholesterogenesis from 3H2O. These data suggest the following: a) fatty acid synthesis responds selectively to 18:0, 18:1, and 18:2; b) the inhibition of fatty acid synthesis by unsaturated fatty acids is time dependent; c) the rate of fatty acid synthesis is inversely proportional to the concentration of unsaturated dietary fat; d) prolonged feeding with a completely saturated diet will increase fecal fat excretion and hepatic cholesterol synthesis; and e) the regulation of fatty acid synthesis by dietary lipid is independent of the regulation of cholesterol synthesis.

Emulsification properties of groundnut protein.

Abstract: The ability of groundnut protein to emulsify soybean oil was studied under various experimental conditions. The emulsification capacity (EC) of groundnut protein isolate was highest at 5 mg/ml protein concn. The EC vs. pH profile resembled a typical protein solubility curve and the EC of groundnut protein isolate was greatest at pH 10.0. NaCl at low concn. (0.05-0.2M ) increased the EC of protein dispersed, in the pH range 7-10. Groundnut protein isolate showed poor emulsifying properties in water (pH 6.8) in contrast to casein or soybean protein. Results with groundnut flour indicated that it was a less effective emulsifier than the protein isolate. EC increased with the fineness of the flour, indicating the influence of particle size. A smaller amount of oil was emulsified at higher mixing speeds.

Flavor and oxidative stability of hydrogenated and unhydrogenated soybean oils: Effects of antioxidants

Abstract: Flavor and oxidative stabilities were studied by organoleptic evaluation and chemical analysis of three different samples of soybean oil: unhydrogented (I); hydrogenated with nickel catalyst (II); and hydrogenated with copper-chromium catalyst (III). Analyses for these oils were: I II III iodine Value 138 109 113 Linolenate, % 8.3 3.3 0.4 Each oil was deodorized with the addition of either citric acid alone or citric acid plus BHA and BHT antioxidants. Addition of antioxidants did not improve the flavor stabilities of the oils in accelerated storage tests but did improve the flavor stabilities of II and III in light exposure tests. All three oils that received the same additive treatment had equivalent flavor stability in both accelerated storage and light exposure tests. However, both hydrogenation and antioxidant treatment improved oxidative stability as measured by the Active Oxygen Method. There was good correlation between flavor score and the logarithm of the peroxide value determined at the time of tasting.

The role of dietary long chain fatty acids in mitochondrial structure and function. Effects on rat cardiac mitochondrial respiration.

Abstract: To evaluate the effect of dietary rapeseed oils on cardiac mitochondrial function and metabolic conservation of energy, male weanling rats derived from the Sprague-Dawley strain were fed three rations containing either 15% (w/w) soybean oil, low erucic acid rapeseed oil or a high erucic acid rapeseed oil. Cardiac mitochondria were isolated for measurement of mitochondrial respiratory functions. Pyruvate and malate plus malonate or succinate plus amytal, or alpha-ketoglutarate and malate plus malonate were utilized as substrates for oxidative phosphorylation. Net rates of state 3 oxygen uptake and therefore ATP synthesis were found to decline with chronic feeding of the 15% (w/w) oil containing diets. Significantly reduced ADP/O ratios were observed for groups fed high erucic acid rapeseed oil containing diets for 11 days. Decreased ADP/O ratios were also observed for groups fed high or low erucic acid rapeseed oils for 112 days. When pyruvate and malate plus malonate were utilized as substrates, reduced rates of ATP synthesis were observed after chronic feeding of high erucic acid rapeseed oil diets. Only prolonged feeding of low erucic acid rapeseed oils resulted in significant alterations in the efficiency of oxidative phosphorylation.

Steam‐Refined soybean oil: II. effect of degumming methods on removal of prooxidants and phospholipids

Abstract: The first paper in this series described the effect of refining and degumming methods on the quality of steam- and caustic-refined soybean oils. Flavor evaluations demonstrated that phosphoric acid-pretreated oils were superior to water-degummed oils particularly in the steam-refining mode. The present study reports observations on the function of the phosphoric acid pretreatment. The effects of iron on the flavor and oxidative stability are reviewed. Data on phosphatide and iron removal during caustic and steam refining are presented and the results discussed. The poor initial quality of the water-degummed, steam-refined oil is attributed to oxidation resulting from incomplete iron removal during the prerefining stage. Significant correlations were obtained between the initial flavor scores of processed oils and their iron contents. Phosphoric acid pretreatment apparently alters iron compounds in crude soybean oil and facilitates their removal during subsequent processing.

Steam-Refined Soybean Oil: I. Effect of Refining and Degumming Methods on Oil Quality'

Abstract: A lot of commercially extracted crude soybean oil was water degummed with and without a phosphoric acid pretreatment. The degummed oils were bleached and then deacidified-deodorized in a single step to yield physically (steam) refined soybean salad oils. Their flavor and oxidative stability were compared to caustic-refined oils given otherwise identical processing treatments. Physically refined oils without a phosphoric acid pretreatment were of poor initial quality compared to those given the phosphoric acid pretreatment. However, caustic- and steam-refined oils processed with the phosphoric pretreatment were of comparable quality.

Pretreatment of soybean oil for physical refining: Evaluation of efficiency of various adsorbents in removing phospholipids and pigments

Abstract: A study was conducted on the efficiency of several adsorbents (Tonsil L80, Tonsil ACC, Fuller’s earth, Celite, Kaoline, silicic acid, and Florosil) in removing phospholipids and color bodies from phosphoric acid degummed soybean oil. Best results under the condi-tions of the experiments were obtained with Tonsil L80 at a 2% concentration and 100 C (reduction in phosphorus content from 17.3 to 3.1 μ/g oil, and in photometric color from 21.6 to 2.4). Removal of phospholipids from the oil by Tonsil L80 and Tonsil ACC follows the Freundlich equation. A colorimetric method for determination of microamounts of phos-pholipids and a spot test for their quantitative evalua-tion were also developed.

Removal of phosphorus and iron by commercial degumming of soybean oil

Abstract: Samples of crude and water-degummed soybean oils were obtained from five commercial processors. period of at least 2 weeks between samples. The crude and degummed oils were analyzed for iron and phosphorus content. Phosphorus removal within each processing plant was consistent, but between plants removal varied from a low of 79% to a high of 95%. Removal of iron compounds during commercial degumming varied from a low of 14% to a high of 57%. Significance of these results in steam-refining operations are discussed.

Thermosetting resin composition

Abstract: PURPOSE: To prepare a thermosetting resin composition useful for electrical insulation and having low odor, by dissolving an unsaturated polyester resin modified with a vegetable oil or its fatty acid, in an unsaturated carboxylic acid ester. CONSTITUTION: A thermosetting resin composition is prepared by mixing (A) 5W95 parts by weight of a reactive diluent comprising one or more acrylic esters or their substituted derivatives (e.g. dibutly itaconate, 2-hydroxyethyl methacrylate, etc.), with (B) 95W5 parts by weight of an unsaturated polyester resin modified with a vegetable oil (e.g. soybean oil, etc.) or its fatty acid. EFFECT: Environmental pollution such as ill odor and air pollution are removed. COPYRIGHT: (C)1979,JPO&Japio

Selective hydrogenation of soybean oil: IX. Effect of pressure in copper catalysis

Abstract: Selective hydrogenation of soybean oil with copper catalyst at 50 psig or less is characterized as a relatively slow reaction requiring higher catalyst concentrations than the less selective but rapid nickel-catalyzed reactions used in most commercial practice. Hydrogenations of soybean oil have been performed which included a high-pressure scan (500, 1000, and 3000 psig), at selected temperatures (110, 130, 150, and 170 C), and at specific catalyst concentrations (0.05, 0.1, 0.2, and 0.4% copper). Selectivities, relative reaction rates, and geometric and positional isomerization have been determined as an evaluation of the effects of high pressure on the kinetics of the reaction. The experimental results indicate that an appropriate selection of pressure, temperature, and catalyst concentration can permit: (a) a significant increase in the rate of reaction while retaining the high linolenic acid selectivity of copper catalysts, (b) use of lower concentrations of copper catalyst while maintaining the higher reaction rate, and (c) elimination of conjugated diene as a measureable product in the hydrogenated oil.

Factor for converting elemental phosphorus to acetone insolubles in crude soybean oil

Abstract: The official AOCS method CA 12-55 contains a factor of 30 in an equation for relating the phosphorus content of crude soybean oil to equivalent phosphatide. The historical derivation of this factor is discussed. The mean value was calculated to be 31.7 ±0.9 by correlation of phosphorus content with acetone insolubles in six lots of crude oil.

The effect of dietary erucic acid on cardiac triglycerides and free fatty acid levels in rats.

Abstract: Male Sprague-Dawley rats, 3 weeks of age, were fed semisynthetic diets containing test oils at 20% by weight for 3 days, 1 week, and 16 weeks. The test oils contained up to 22.3% erucic acid. Growth retardation was evident in rats fed rapeseed oil high in erucic acid, and soybean oil and Tower rapeseed oil diets containing about 5% erucic acid. Cardiac triglyceride accumulation was found in rats fed diets containing about 5% erucic acid but not in rats fed Tower rapeseed oil which contains 0.2% of this acid. The cardiac free fatty acid levels were low, 50–100 μg/g of wet heart tissue, and were not affected by feeding diets containing about 5% erucic acid. Feeding a diet containing a high erucic acid rapeseed oil did result in higher free fatty acid levels but only at 3 days and 1 week; the level at 16 weeks was similar to the other oils. The fatty acid analysis of cardiac triglycerides and free fatty acids showed high percentages of erucic acid at 3 days and 1 week; at 16 weeks these levels had declined significantly. The results indicate that the accumulated erucic and eicosenoic acids, at 3 days and 1 week, accounted for the increase in cardiac free fatty acids when rats were fed the high erucic acid rapeseed oil. There appears to be no evidence that the early cardiac triglyceride or free fatty acid accumulation is related to the formation of the long term myocardial lesions.

Effect of glucose or oil supplementation on lipogenic enzymes in overfed chicks.

Abstract: Chicks of a light breed, aged 26 days, were force-fed by intubation for 10 days. The feed administered consisted of a basal low-fat closed formula cereal based diet and of supplements of either glucose or soybean oil supplied in isoenergetic amounts. Ad libitum-fed chicks served as controls. At the end of the experiment, the weights and lipid contents of carcass, livers and abdominal adipose tissue were determined, as was the glucose and lipid content of plasma. In addition the activities of citrate cleavage and malic enzymes were assayed in livers and adipose tissue. The increased weight and lipid content caused by glucose or oil supplements were similar in carcass and adipose tissue, but liver weight and fat content were increased much more by the glucose supplement than by the oil. The lipids which accumulated in the livers of force-fed chicks were essentially triglycA©rides. The glucose supplement caused a pronounced drop in the linoleic acid content of liver lipids, as well as an increase in oleic acid, whereas the oil produced the opposite effect. The glucose supplement caused a more pronounced hyperglycemia and hyperlipemia than did the oil. Activities of citrate cleavage and malic enzymes increased in proportion to the amount of carbohydrates force-fed in excess of the control intake. These and previous results show that chicks adapt to excess carbohydrate intake by both liver enlargement and increased activity of lipogenic en zymes. ' J. Nutr. JOS: 490-496, 1978.

Distribution of chlorinated pesticides in soybeans, soybean oil, and its by‐products during processing

Abstract: Soybean samples were collected from seven different locales in Central Illinois and subjected to analysis for chlorinated pesticides. Different parts of the beans showed varying levels of residue concentrations. It was found that pesticide residues had a tendency to accumulate, in descending order, in hypocotyls, hulls and cotyledons on the basis of ground samples. When oils extracted from the same fractions were analyzed, much higher concentrations of residues were located in hulls than hypocotyls, which had greater concentrations than cotyledons. Crude, refined, bleached and deodorized oils, soapstock, Fuller’s earth sludge and deodorization condensate swere analyzed for hexachlorobenzene isomers, heptachlor, heptachlor epoxide, aldrin, dieldrin, DDT, DDD and DDE. None of the processing steps except deodorization were completely effective in the removal of chlorinated pesticide residues. Oil deodorized at 250 C under 1-5 mm pressure was almost free of such residues, whereas all the residues were concentrated in deodorization condensate.

Evaluation of low erucic acid rapeseed oil fed to monkeys: cardiac lipids, histochemistry and pathology

Abstract: Male and female cynomolgus monkeys (Macaca fascicularis), equally divided as to sex, were fed, up to 24 wk, diets which contained 20% by weight of either soybean oil or Brassica napus cv. Tower rapeseed oil which contained 0.2% erucic acid. Long-chain monoenes appeared to accumulate in the cardiac lipids of both sexes fed Tower rapeseed oil. Histochemical studies suggested no myocardial damage associated with the feeding of either diet. Histopathological examination of the hearts of monkeys fed the two diets showed that only two male monkeys fed soybean oil for 24 wk had myocardial lesions, and these were multiple small foci of mononuclear cells. The results indicate that Tower rapeseed oil is indistinguishable from soybean oil in its nutritional and pathological properties.

Prevention of heat browning of phospholipid

Abstract: PURPOSE: To suppress the heat browning of phospholipid by adding amino acids to the oil or fat containing phospholipid. CONSTITUTION: In the process for the preparation of a phospholipid-containing oil or fat comprising dissolving or dispersing 0.2 wt% of a phospholipid such as soybean phospholipid, lecithin, etc. to oil or fat such as soybean oil, butter, etc., followed by heating the solution, etc. at ≥150°C, ≥0.3 wt%, pref. ≥3 wt% of amino acids except S-containing amino acids, e.g. glycine, alanine, etc., are added to the solution, etc., before or during the heating. COPYRIGHT: (C)1979,JPO&Japio

Production of an edible oil from crude soy oil

Abstract: Production of edible soybean oil from raw soybean oil extracted from soybeans by first moistening soybean flakes to raise their water content to 12 to 25% by weight and subjecting the moistened flakes to heat treatment at 90° to 120° C. and thereafter extracting crude soybean oil from the treated flakes with a non-polar solvent; subjecting the crude soybean oil, after removal of lecithin therefrom, to bleaching without a separate desliming step; and thereafter deodorizing with simultaneous deacidizing the bleached soybean oil.

Process of epoxidation of oils

Abstract: Epoxidation of oil, such as soybean oil, using a peracid, is performed in the presence of a complexing agent for heavy metals selected from nitriloacetic, cyclohexane aminotetracetic and diethylenetriaminopentacetic acids.

Continuous hydrogenation of fats and fatty acids at short contact times1

Abstract: Continuous hydrogenation of fats and fatty acids using suspended catalysts was studied in a vertical flow reactor packed with Raschig rings. A short time of reactive contact of the fat or the fatty acid with the catalyst and hydrogen is the unique feature of this system. A nickel catalyst used in the hydrogenation of soybean oil gave a reduction of 40-50 iodine value units per min, small amounts oftrans-isorners (10-20%), large proportions of linoleate in unreduced octadecadienoyl moieties (70-80%), and nonselective reduction of polyunsaturated acyl moieties (linoleate selectivity ratio 1-3). Another nickel catalyst, used in the hydrogenation of tallow fatty acids, also gave a reduction of 40-50 iodine value units per min and nonselective reduction of polyunsaturated fatty acids. A copper chromite catalyst used in the hydrogenation of soybean oil gave a reduction of 10-15 iodine value units per min, low levels oftrans- isomers (10-15%), and selective reduction of linolenoyl moieties (linolenate selectivity ratio 4-6). Composition of positional isomers of cis- andtrans-octadecenoyl moieties in partially hydrogenated products obtained both with nickel and copper chromite catalysts reveals that essentially the same mechanisms of isomerization are involved in continuous hydrogenation at short time of reactive contact as in batch hydrogenation.

Effect of dietary fats and fatty acid on liver lipid accumulation in rats fed low protein diets.

Abstract: This study was conducted to evaluate influences of dif ferent dietary fats and fatty acid on the lipid accumulation in the liver of growing rats fed low protein diets containing purified whole egg pro tein at 5 protein calories percent (PC%). Rats were fed for 2 (experi ment 1) or 3 (experiment 2) weeks. In experiment 1, rats fed low protein diets with 0.1% soybean oil accumulated more lipids in the liver than those fed a control (20 PC%) diet with 10% soybean oil. The excess accumulation of lipids tended to be inhibited by the further addition of 9.9% soybean oil and was inhibited by 9.9% linoleic acid. In experi ment 2, the lipid content in the liver of rats fed the low protein diet with 9.9% lard was lowered by substituting 9.9% soybean oil, safflower oil and linoleic acid for lard. However, even rats fed the low protein diet with linoleic acid accumulated still more lipids in the liver than those fed the control diet. Furthermore, the liver lipid level in rats fed low protein diets with 20% soybean oil was almost the same to that in rats fed the low protein diet with 10% soybean oil. From these results, the mecha nism of lipid accumulation in liver of the rat fed low protein diet was discussed.

Effects of Vegetable Oils on the Biological Disposition of Ethchlorvynol. II. The Effects on the Brain Distribution of Ethchlorvynol in Rat

Abstract: The blood and tissue levels of unchanged ethchlorvynol (EC) were determined after intraperitoneal administration of EC suspended in 5% polyethylene glycol 400 aqueous solution (5% PEG). Pre-oral administration of 5% PEG did not show any effect on the levels of EC in blood and tissues, compared with the pre-treatment of normal saline as a control. However, pre-administered corn oil as well as peanut oil and soybean oil decreased the brain levels of EC. In order to exclude the effect of the vegetable oils, the thoracic fistula rats were used in the studies. When EC was administered orally in corn oil to the fistula rats, the brain levels of EC were fairly improved, and were higher than in the intact rats. As little as 0.06 and 0.05% of total dose were recovered in the lymph as EC and EC-glucuronide (ECG), respectively after oral administration of EC in corn oil. While both EC and ECG were not detected in the lymph when EC was given in 5% PEG.

A Beverage Base From Cheese Whey and Peanut Flour

Abstract: Fluid sweet whey, defatted peanut flour, soybean oil, and corn syrup solids were processed with conventional dairy plant equipment to form a free flowing powder reconstitutable with water to form a nutritious beverage. A formulation containing 50% sweet whey solids, 20% soybean oil, 24.6% defatted peanut flour, and 5.4% com syrup solids had a proximate composition of 20.6% protein, 5% ash, 21.6% fat, 3.5% moisture, 1% fiber, and 48.3% carbohydrate. The standardized protein efficiency ratio was 2.0 compared to casein at 2.5, and nitrogen digestibility was 80% compared to casein at 93%. The flavor quality was bland initially; however, decreased flavor scores coupled with increased peroxide values in the blend during storage were indicative of a serious stability problem.

Preparation of oil for meat-roasting hot plate

Abstract: PURPOSE: To prepare an oil for applying to a meat-roasting hot plate, by mixing a substance which emits CO 2 gas by heating to a phospholipid-containing oil, heating the mixture, and adding and dissolving the mixture to a vegetable oil to obtain a specific phospholipid content CONSTITUTION: (A) A phospholipid existing in oils and fats in a concentration of ≥10 wt%, is mixed with (B) a substance which emits CO 2 gas by heating (eg Sodium bicarbonate) The mixture is heated at ≥80°C, and, after filtering in option, added to a vegetable oil such as soybean oil to obtain the phospholipid content of 05W5 wt% EFFECT: Sputtering phenomenon can be completely suppressed without causing discoloration COPYRIGHT: (C)1979,JPO&Japio

Coated fumaric acid preparation for food or feed additive and its production

Abstract: PURPOSE: To liquid emulsion of a fumaric acid powder containing a sugar fatty acid ester and an edible oil is sprayed and cooled to produce said coated fumaric acid preparation for food and feed additive with high fumaric acid content and good properties. CONSTITUTION: An edible fat melting over 40°C, preferably at 45W90°C, e.g., soybean oil, palm oil, tallow oil or fish oil, is heated at a temperature over the melting point and combined with sugar ester of fatty acid to dissolve it with stirring. Then, fumaric acid is dispersed in the solution. The resulting dispersion is sprayed into a chamber kept to a temperature lower than the melting point, thus producing said coated fumaric acid preparation that is composed of 50W75wt% of powdered fumaric acid, 0.05W5wt% of sugar fatty ester and the rest of edible fat and in which the fumaric acid is coated with the edible fat and the sugar fatty ester and the particle size is 300μ or less on the average. COPYRIGHT: (C)1980,JPO&Japio

An oil fraction from edible beef tallow as a constituent of whey-soy drink mix

Abstract: In order to increase its potential as a food ingredient, an oil fraction derived from a commercial edible beef tallow was substituted for soybean oil in a formulation designed to yield a spray-dried free-flowing powder readily reconstitutable with water to yield a nutritious beverage. If desired, the beverage powder could be fortified with a vitamin-mineral premix containing iron. After 6 months of storage at 37 C, no significant difference in flavor score was observed between samples containing the beef tallow oil fraction and control samples containing soybean oil. There was also no significant difference in flavor scores received by samples containing the beef tallow oil fraction fortified with vitamins and minerals and fortified control samples. However, peroxide values were eight times greater in the unfortified control samples. The beef tallow oil fraction warrants further study as a food ingredient in engineered food systems where enhanced oxidative stability is desirable.

Effect of Citric Acid on the Oxidative and Flavor Stability of Soybean Oil

Abstract: Citric acid was added into the deodorized soybean oil. Citric acid content in the oil was determined by GLC wtih 5% Silicone OV-17 and the effect of citric acid on the oxidative and flavor stability of the soybean oil was tested. Citric acid did not protect the oil against fluorescent light. On the other hand, citric acid markedly improved flavor and oxidative stability when the oils were deteriorated under spontaneous autoxidation conditions. However, its efficiency was independent of its concentration. Citric acid solubility in the soybean oil was measured. At least 50ppm citric acid could be dissolved in the oil after 4 weeks of storage.