Showing papers on "Soybean oil published in 1996"

Fast one-phase oil-rich processes for the preparation of vegetable oil methyl esters

Abstract: A re-evaluation of kinetic data shows that the methoxide base-catalyzed methanolysis of soybean oil at 40°C (6:1 methanol:oil molar ratio) to form methyl esters proceeds approximately 15 times more slowly than butanolysis at 30°C. This is interpreted to be the result of a two-phase reaction in which methanolysis occurs only in the methanol phase. Low oil concentration in methanol causes the slow reaction rate; a slow dissolving rate of the oil in the methanol causes an initiation period. Intermediate mono- and diglycerides preferentially remain in the methanol, and react further, thus explaining the deviation from second-order kinetics. The same explanations apply for hydroxide ion catalyzed methanolysis. At the 6:1 methanol:oil molar ratio the addition of a cosolvent, such as 1.25 volumes of tetrahydrofuran (THF) per volume of methanol, produces an oil-dominant one-phase system in which methanolysis speeds up dramatically and occurs as fast as butanolysis. The critical separation of the glycerol-rich phase still occurs and does so faster than in the cosolvent-free system. For THF, recycle of solvent is simplified because of the similar boiling points of THF (67°C) and methanol (65°C). Possible explanations for the abnormal slowing of the methanolysis reactions are presented in terms of (1) lower rate constants for mono- and diglyceride reactions due to the formation of cyclic intermediates, (2) a fall in the polarity of the reaction mixture due to either methanol depletion or mixing of the oil, methanol and cosolvent, and (3) depletion of hydroxide ion when this is present.

High-fat diet-induced hyperglycemia and obesity in mice: Differential effects of dietary oils

Abstract: Mice fed a high-fat diet develop hyperglycemia and obesity. Using non-insulin-dependent diabetes mellitus (NIDDM) model mice, we investigated the effects of seven different dietary oils on glucose metabolism: palm oil, which contains mainly 45% palmitic acid (16:0) and 40% oleic acid (18:1); lard oil, 24% palmitic and 44% oleic acid; rapeseed oil, 59% oleic and 20% linoleic acid (18:2); soybean oil, 24% oleic and 54% linoleic acid; safflower oil, 76% linoleic acid; perilla oil, 58% alpha-linolenic acid; and tuna fish oil, 7% eicosapentaenoic acid and 23% docosahexaenoic acid. C57BL/6J mice received each as a high-fat diet (60% of total calories) for 19 weeks (n = 6 to 11 per group). After 19 weeks of feeding, body weight induced by the diets was in the following order: soybean > palm > or = lard > or = rapeseed > or = safflower > or = perilla > fish oil. Glucose levels 30 minutes after a glucose load were highest for safflower oil (approximately 21.5 mmol/L), modest for rapeseed oil, soybean oil, and lard (approximately 17.6 mmol/L), mild for perilla, fish, and palm oil (approximately 13.8 mmol/L), and minimal for high-carbohydrate meals (approximately 10.4 mmol/L). Only palm oil-fed mice showed fasting hyperinsulinemia (P < .001). By stepwise multiple regression analysis, body weight (or white adipose tissue [WAT] weight) and intake of linoleic acid (or n-3/n-6 ratio) were chosen as independent variables to affect glucose tolerance. By univariate analysis, the linoleic acid intake had a positive correlation with blood glucose level (r = .83, P = .02) but not with obesity (r = .46, P = .30). These data indicate that (1) fasting blood insulin levels vary among fat subtypes, and a higher fasting blood insulin level in palm oil-fed mice may explain their better glycemic control irrespective of their marked obesity; (2) a favorable glucose response induced by fish oil feeding may be mediated by a decrease of body weight; and (3) obesity and a higher intake of linoleic acid are independent risk factors for dysregulation of glucose tolerance.

Changes in the characteristics and composition of oils during deep-fat frying

Abstract: Refined, bleached, and deodorized soybean oil and vanaspati (partially hydrogenated vegetable oil blend consisting of peanut, cottonseed, nigerseed, palm, rapeseed, mustard, rice bran, soybean, sunflower, corn, safflower, sesame oil, etc., in varying proportions) were used for deep-fat frying potato chips at 170, 180, and 190°C. Refractive index, specific gravity, color, viscosity, saponification value, and free fatty acids of soybean oil increased with frying temperature, whereas the iodine value decreased. The same trend was observed in vanaspati, but less markedly than in soybean oil, indicating a lesser degree of deterioration. Iodine values of soybean oil and vanaspati decreased from their initial values of 129.8 and 74.7 to 96.2 and 59.6, respectively, after 70 h of frying. Polyunsaturated fatty acids decreased in direct proportion to frying time and temperature. Losses were highest in soybean oil with a 79% decrease in trienoic acids and a 60% decrease in dienoic acids. Levels of nonurea adduct-forming esters were proportional to the losses of unsaturated fatty acids. Butylated hydroxyanisole and tertiary butylhydroquinone did not affect deterioration of soybean oil at frying temperatures.

Influence of pH on lipolysis and biohydrogenation of soybean oil by rumen contents in vitro

Abstract: The effect of different pH values on rumen lipolysis and biohydrogenation was investigated during incubations of the rumen contents with 40 or 80 mg of soybean oil as the sole substrate. Mean pH values studied were 6.8, 6.3, 6.0, 5.6 and 5.2. Lipolysis was calculated from the decrease in fatty acids present in triacylglycerols (TAG), as well as from the accumulation of free fatty acids (FFA) during the incubation. At pH < or = 6.0 lipolysis was low, and the inhibition became greater with decreasing pH. At the same pH value, the inhibition in incubations with 80 mg of soybean oil was more pronounced than with 40 mg. Even at the lowest pH value, after incubation, no free linolenic acid could be detected because of biohydrogenation, whereas linoleic acid hydrogenation was only partially inhibited at pH 5.2. This means that lipolysis is much more sensitive to low pH values than biohydrogenation. Literature data indicate however that, besides pH, other factors must be involved in the decrease of both lipolysis and biohydrogenation in the rumen of animals fed highly concentrated diets.

Development of genetically engineered soybean oils for food applications

Abstract: The major use of the ten billion pounds or so of soybean oil produced in the US is for food products such as cooking oils, shortenings and margarines. Refined, bleached and deodorized (RBD) soybean oil used for cooking is usually hydrogenated to increase storage life and stability during frying. RBD soybean oil is also extensively hydrogenated to increase melting point for functionality in shortenings and margarines. Hydrogenation results in oils rich in trans fatty acids, the consumption of which may be associated with coronary heart disease. RBD oils used for salad oils are not hydrogenated but are rich in palmitic acid, the consumption of which has also been associated with coronary heart disease. Therefore, it is nutritionally desirable to produce trans-free soybean oils rich in monounsaturated fatty acids with reduced palmitic acid for cooking and soybean oils with no saturated fatty acids for salad oils. It is also desirable to produce trans-free oils rich in stearic and oleic acids for shortenings and margarines. Cloned genes may be introduced into soybeans to create transgenic lines with improved oil traits. The design of transgene constructs has been assisted by the use of soybean somatic embryos in suspension culture as a model system for soybean seed transformation. This system has allowed the selection of the right genes and promoters to achieve the desired phenotypes in transgenic soybeans. Current soybeans in development include lines producing oil with reduced palmitic acid, lines with over 80% oleic acid and lines with up to 30% stearic acid. Commercialization of high oleic acid transgenic soybeans has demonstrated that it is possible to drastically alter the fatty acid composition of a soybean seed without affecting the yield or environmental sensitivity of the soybean plant.

The effect of parenteral fish oil on leukocyte membrane fatty acid composition and leukotriene-synthesizing capacity in patients with postoperative trauma.

Abstract: The incorporation of omega-3 and omega-6 fatty acids (FAs) into leukocyte membranes and the leukotriene (LT)B4-, LTB5 -, LTC4-, and LTCs-synthesizing capacity in stimulated leukocytes were measured following parenteral omega-3 FA nutrition in 20 postoperative patients. Total parenteral nutrition (TPN) over 5 days postoperatively was isonitrogenous (0.24 g N x kg-1 x d1) and isoenergetic (92 kJ/22 kcal x kg-1 x d-1), containing 0.15 g fish oil and 0.85 g soybean oil per kg-1 x d-1 (FO) or 1.0 g soybean oil x kg-1 x d-1 (SO). Following 5 days' FO administration, the content of eicosapentaenoic acid (EPA) was increased 2.5-fold, LTB5 1.5-fold, and LTC5 sevenfold. With SO nutrition, EPA and LTB5 generation remained unaltered, whereas LTC5 doubled. The production of LTB4 and LTC4 was not affected in any of the groups. We conclude that a 5-day parenteral fish oil supplementation has an immunomodulatory effect on lipid-mediator generation in human leukocytes in postoperative trauma.

Combustion Analysis of Esters of Soybean Oil in a Diesel Engine

Abstract: The alkyl esters of plant oils and animal fats are receiving increasing attention as renewable fuels for diesel engines. These esters have come to be known as biodiesel. One objection to the use of the methyl and ethyl esters of soybean oil as a fuel in diesel engines is their high crystallization temperature. One solution to this problem is to use the isopropyl esters of soybean oil which have significantly lower crystallization temperatures. Another method to improve the cold flow properties of esters is to winterize them to subambient temperature. This is accomplished by cooling the esters and filtering out the components that crystallize most readily. Previous work has shown that when methyl, isopropyl and winterized ester blends were compared with No. 2 diesel fuel, the isopropyl and winterized methyl esters had at least the same emission reduction potential as the methyl esters, with similar engine performance. This paper discusses those results using heat release analysis that shows all of the blends have shorter ignition delays, and lower premixed burn fractions than No. 2 diesel fuel. All tested fuels except the isopropyl ester blends had similar combustion behavior. However, blends with isopropyl ester showed some abnormal combustion behavior, possibly duemore » to high levels of monoglycerides.« less

Reducing the crystallization temperature of biodiesel by winterizing methyl soyate

Abstract: Methyl soyate, made from typical soybean varieties, has a crystallization onset temperature (T co) of 3.7°C and, as a biodiesel fuel, is prone to crystallization of its high-melting saturated methyl esters at cold operating temperatures. Removal of saturated esters by winterization was assessed as a means of reducing theT co of methyl soyate. Winterizing neat methyl esters of typical soybean oil produced aT co of −7.1°C, but this was not an efficient way of removing saturated methyl esters because of the low yield (26%) of the separated liquid fraction. However, aT co of −6.5°C with 86% yield was obtained by winterizing the neat methyl esters of a low-palmitate soybean oil; aT co of −5.8°C with 77% yield was obtained by winterizing methyl esters of normal soybean oil diluted with hexane.

Deacidification of soybean oil by membrane technology

Abstract: After extracting free fatty acids (FFA) from a model crude vegetable oil with methanol, FFA were separated from methanol by nanofiltration. Of the several commercially available membranes that were evaluated, the best resulted in FFA rejection of >90% and flux of >25 Lm−2h−1. A combination of high-rejection and low-rejection membranes resulted in a retentate stream of 35% FFA and a permeate stream with less than 0.04% FFA, which can be recycled to the extractor. No alkali is required, no soapstock is formed, and almost all streams within the membrane process are recycled with little discharged as effluent.

Total frying‐use time effects on soybean‐oil deterioration and on tortilla chip quality

Abstract: Refined soybean oils were degraded at 190°C for 60 h to a total polar material of 61.54%. The effect of fresh to highly degraded oil on the physical and thermal properties of the oil as well as on the final quality of tortilla chips was determined. Surface tension decreased significantly with oil degradation (P < 0.05). Colour readings also changed significantly with oil degradation (P < 0.05) and were more pronounced after 30 h of frying. Foam and off-flavour developed between 20 and 30 h of degradation suggesting that the oil should have been discarded when the total polar material reached 27%. The convective heat transfer coefficient changed more rapidly after 30 h of frying. The values of the convective heat transfer coefficient correlated highly with viscosity (-0.98). The oils, whether fresh or degraded, behaved as Newtonian fluids. Viscosity was significantly affected by oil degradation time and temperature (P < 0.05). The effect of temperature on the viscosity of the oils was described by an Arrhenius equation. Viscosity changed more rapidly with temperature as the degradation time increased. Tortilla chips were fried in fresh and degraded soybean oils. Total oil content and fracturability of tortilla chips were not affected significantly by oil degradation time (P < 0.05). However, the oil content adhering to the surface of the tortilla chips was significantly higher (P < 0.05) in the tortilla chips fried in degraded oil than in fresh oil.

In-situ alcoholysis of soybean oil

Abstract: In-situ alcoholysis of soybean oil with methanol, ethanol,n-propanol, andn-butanol was investigated, as well as the extraction of the oil with these solvents, to explain the progress ofin-situ alcoholysis and to determine the parameters that affect this reaction Because methanol is a poor solvent for soybean oil, the amount of oil dissolved in methanol and converted to methyl esters was low afterin-situ alcoholysis Ethyl, propyl, and butyl esters of soybean fatty acids could be obtained in high yields fromin-situ alcoholysis of soybean oil with these alcoholsIn-situ alcoholysis proceeded through dissolution and alcoholysis of triglycerides successively, and the overall reaction rate was determined by the extraction and alcoholysis rates The parameters, affecting yield and purity of the product esters, were mainly those that favor extraction rate

Fall in total cholesterol concentration over five years in association with changes in fatty acid composition of cooking oil in Mauritius: cross sectional survey

Abstract: Objective : To determine the extent to which reducing the saturated fatty acid composition of a ubiquitously used cooking oil influenced changes in cholesterol concentration in the population during a five year intervention programme in Mauritius. Design : Cross sectional surveys in 1987 and 1992 determined mean total cholesterol concentrations in the population. A random sample of respondents in the 1992 survey completed a nutrition questionnaire that included questions on diet in the previous 24 hours. Setting : Mauritius. Intervention : In 1987 the government of Mauritius changed the composition of the commonly used cooking oil from being mostly palm oil (high in saturated fatty acids) to being wholly soya bean oil (high in unsaturated fatty acids). Subjects : 5080 and 5162 subjects in 1987 and 1992 cross sectional surveys. 2059 subjects aged 30–64 years were randomly selected from the respondents of the 1992 survey to take part in the nutrition survey Main outcome measures : Fatty acid composition of phospholipids in pooled serum samples from men and women from the two surveys; measured and predicted change in serum cholesterol concentration. Results : From 1987 to 1992 total cholesterol concentrations fell significantly by 0.79 mmol/l (P Conclusion : Dietary changes that entailed a reduction in the saturated fat content of a ubiquitous cooking oil explained most of the observed decrease in serum cholesterol concentration over five years in the population of Mauritius. Key messages The saturated fatty acid intake of Mauritians was reduced by modifying the composition of the widely used cooking oil Mean serum cholesterol concentration decreased by 15% after the cooking oil intervention was introduced nationwide Effective, low cost prevention programmes for chronic disease are needed in less industrialised countries. Simple action in dietary policy could be one such strategy

Methanolysis of seed oils in flowing supercritical carbon dioxide

Abstract: The direct methanolysis of triglycerides in flowing supercritical carbon dioxide by an immobilized lipase is described. The reaction system consists of two syringe pumps for substrate addition and another two syringe pumps for delivering CO2 at 24.1 MPa. Corn oil is pumped into the carbon dioxide stream at a rate of 4 μL/min, and methanol is pumped at 5 μL/min to yield fatty acid methyl esters (FAME) at >98% conversion. Direct methanolysis of soy flakes gives FAME at similar yields. This combined extraction/reaction is performed at 17.2 MPa and 50°C. The fatty acid profiles obtained for these seed oils matches those obtained by classical chemical synthesis.

Soybean seed composition under high day and night growth temperatures

Abstract: High diurnal temperatures often affect development of soybean [Glycine max (L.) Merr.], but little is known about the relative influence of high day and night temperatures on the chemical composition of the seed. This study was conducted to determine the effects of combinations of high day and night temperatures during flowering and pod set (R1–R5), seed fill and maturation (R5–R8), and continuously during the reproductive period (R1–R8) on soybean seed oil, protein, and fatty acid composition. Day/night temperatures of 30/20, 30/30, 35/20, and 35/30°C were imposed on the soybean cultivar Gnome 85 in growth chambers. The day/night temperature combinations during R1–R5 had little effect on the oil and protein concentration and the fatty acid composition of seed produced. As mean daily temperature increased from 25 (30/20) to 33 (35/30)°C during R5–R8 and 25 (30/20) to 33 (35/30)°C during R1–R8, and oil concentration decreased and protein concentration increased. Increased day temperature during R5–R8 and R1–R8, averaged across the two night temperatures, increased oleic acid and decreased linoleic and linolenic acids. When night temperature was increased at 30°C day temperature during R5–R8 and R1–R8, oleic acid decreased and linoleic acid increased. When night temperature was increased at 35°C day temperature during R1–R8, oleic acid increased, and linoleic and linolenic acids decreased. These results indicate the importance of high day and night temperatures during seed fill and maturation in the oil, protein, and fatty acid composition of soybean seed.

Effect of L-carnitine and soybean oil on growth performance and body composition of early-weaned pigs.

Abstract: Two experiments were conducted to evaluate the effect of dietary L-carnitine on growth performance and body composition of early-weaned pigs. In Exp. 1, 120 weanling pigs (initially 5.6 kg and 19 +/- 2 d of age) were allotted in a 3 x 2 factorial with four pigs per pen and five replications (pens) per treatment. Main effects from d 0 to 14 after weaning included dietary L-carnitine (0, 500, or 1,000 ppm) and soybean oil (0 to 10%). From d 14 to 35 after weaning, levels were reduced to 0, 250, or 500 ppm L-carnitine and 0 or 5% soybean oil. No L-carnitine x soybean oil interactions were observed (P > .10). From d 0 to 14, L-carnitine and soybean oil had no effect (P > .10) on pig performance. From d 14 to 35 and d 0 to 35, gain:feed ratio (G/F) improved (linear, P .10) by dietary L-carnitine. However, pigs fed 1,000 ppm L-carnitine from d 0 to 14 had less (P < .05) carcass lipid and daily lipid accretion on d 35 whether they were fed L-carnitine from d 14 to 35 or not. These results suggest that dietary L-carnitine improves G/F and reduces carcass lipid accretion in early-weaned pigs.

Saturated Sterols (Stanols) in Unhydrogenated and Hydrogenated Edible Vegetable Oils and in Cereal Lipids

Abstract: The content of saturated sterols (stanols) was investigated in a small number of samples of hydrogenated fats and oils, and in the 'free' and 'bound' lipids of various samples of cereals. The sterols, after saponification of the total lipids, were analysed as trimethylsilyl derivatives by GC and identified by GC-MS. Among the hydrogenated fats and oils, coconut oil contained the largest amounts of sitostanol followed by soybean oil (c 80 and 20 g kg -1 of total unsaponifiables, respectively). No sitostanol could be detected in hydrogenated palm oil under the present analytical conditions. Both 'free' and 'bound' lipids in various samples of wheat, except for wheat germ, contained c 70-120 g kg -1 campestanol and 100-150 g kg -1 sitostanol in total unsaponifiables. In lipids of oats and barley, no campestanol or sitostanol could be detected. Rye total lipids contained 60-90 g kg -1 of campestanol and 100-150 g kg -1 of sitostanol of total unsaponifiables in 'free' and 'bound' lipids, respectively.

New Antioxidant Isolated from Tempeh

Abstract: Dried tempeh is known to be significantly stable to lipid oxidation compared with unfermented soybeans (BS). A new antioxidant was isolated from the methanol extract of tempeh and identified as 3-hydroxyanthranilic acid (HAA) by UV, IR, EI-MS, and 1H-, 13C-, HMQC-, and HMBC-NMR techniques. HAA was effective in preventing autoxidation of soybean oil and soybean powder, while 6,7,4‘-trihydroxyisoflavone (a well-known antioxidant) was not. HAA also exhibited strong antioxidative activity in both water/ethanol and rabbit erythrocyte membrane ghost systems. HAA was not found in BS, but was produced during the incubations with Rhizopus oligosporus IFO 32002 and 32003. The amount of HAA reached a maximum at the stage of 2 days (acceptable), which had the strongest antioxidative activity. Keywords: Tempeh; fermented soybean product; antioxidant; 3-hydroxyanthranilic acid

Production of Tocopherol Concentrates by Supercritical Fluid Extraction and Chromatography

Abstract: Supercritical fluid extraction (SFE) has been combined with supercritical fluid chromatography (SFC) in a preparative mode to develop a system for fractionating and enriching high value constituents contained in seed oil matrices. The system consists of an extraction step sequenced on-line with a sorbent filled column, which permits a SFE-enriched tocopherol fraction to be diverted onto the chromatographic column for further enrichment of the tocopherols. For the SFE stage, the tocopherol enrichment was optimized at 25 MPa and 80°C for soybean flakes and rice bran. However, total tocopherol recovery and enrichment was also found to be a critical function of the mass ratio of CO2/seed charge. Approximately 60% of the available tocopherols in soyflakes can be recovered in the SFE step, yielding enrichment factors of 1. 83–4.33 for the four tocopherol species found in soybean oil. Additional enrichment of tocopherol species can be realized in the SFC stage, ranging from 30.8 for delta-tocopherol to ...

Effect of genetic modification on the content and composition of bioactive constituents in soybean oil

Abstract: The content and composition of tocopherols, sterols, and phospholipids in soybean oils derived from genetically-modified soybeans were determined by normal and reverse-phase high-performance liquid chromatography and gas-liquid chromatography. Tocopherol content was lowered in oils from soybeans selected to yield high palmitate and stearate contents. However, β-tocopherol, which amounts to less than 1 ppm in control oils, was increased to 25–53 ppm in these oils. Sterol content was higher in one reduced-linolenate oil, which also had the highest oleate content. The greatest variability was observed in the content of β-sitosterol, which ranged from 46.9–151.6 mg/100/g in the modified oils. Although, in general, there was little impact on the phospholipids, the content of phosphatidic acid was elevated in crude oils from three of the lines. Increases in phosphatidic acid are generally associated with storage deterioration of soybeans. Individual major classes of phospholipid were isolated, and the molecular species composition of each was determined. Compositional variations in molecular species indicated that there was an impact of the genetic modification of soybeans at the molecular level of the phospholipids that are primary plant cell components.

Identification of adulterants in olive oils

Abstract: The application of discriminant analysis for identifying and quantifying adulterants in extra virgin olive oils is presented. Three adulterants were used (sunflower oil, rapessed oil, and soybean oil) and were present in the range 5–95%. Near-infrared spectroscopy and principal components analysis were used to develop a discriminant analysis equation that could identify correctly the type of seed oil present in extra virgin olive oil in 90% of cases. Partial least squares analysis was used to develop a calibration equation that could predict the level of adulteration. Cross validation suggested that it was possible to measure the level of adulteration to an accuracy of ±0.9%. External validation of the derived calibation equation gave a standard error of performance of ±2.77%.

Studies on acid oils and fatty acids for chickens. I. Influence of age, rate of inclusion and degree of saturation on fat digestibility and metabolisable energy of acid oils

Abstract: 1. Using a multi-rate assay, 3 commercial acid oils (sunflower, soyabean and tallow) were evaluated for AMEn and added fat digestibility with broiler chicks, at 11, 25, 39, 53 and 60 d of age. The regression equations of AMEn values or ME of available fat on rate of inclusion of fat were calculated. 2. Significance was achieved for linear regression but not for quadratic regression in both variables; neither rate of inclusion nor age of birds (except for tallow acid oil at 25 d) significantly affected the AMEn or ME of fat. Metabolisable energy of fat (on a dry matter basis) calculated from combined linear regression equations was 19.14MJ/kg for sunflower acid oil, 18.09MJ/kg for tallow acid oil and 27.94MJ/kg for soyabean acid oil. Differences between sunflower and soyabean acid oils were attributed in variations in unsaponifiable and non-eluted materials of both fats. 3. Abdominal fat pad weight and its relationship to carcase weight were also studied with birds slaughtered at 67 d of age. Chicks given tallow acid oil deposited larger amounts of abdominal fat, and this deposition was directly related to the rate of inclusion of acid oil in the diet.

Effect of rapeseed and dietary oils on the mean survival time of stroke-prone spontaneously hypertensive rats

Abstract: Low-fat conventional diets supplemented with 5 or 10% vegetable oils were fed to stroke-prone spontaneously hypertensive rats (SHR-SP) from weaning and the mean survival times were determined. A 1% aqueous sodium chloride solution was used as drinking water throughout the experiments. In four separate experiments, the rapeseed oil group showed a significantly shorter mean survival time. The relative mean survival times were 50-59% (rapeseed oil group), 78-100% (soybean oil group) and 86% (microbial oil group) as compared with the group fed perilla oil (100%). The group which received 4-fold diluted rapeseed oil exhibited a significantly shorter survival time as compared with the group receiving soybean oil. Although the feeding experiments were performed under very simple and restricted conditions, these results suggest that the rapeseed oil prepared for human use contains a factor (s) which is toxic to SHR-SP rats.

Docosahexaenoic acid-rich fish oil does not affect serum lipid concentrations of normolipidemic young adults

Abstract: Fish oils, purified eicosapentaenoic acid and docosahexaenoic acid (DHA) have been reported to improve blood lipid concentrations, especially those of triglycerides in humans. However, to our knowledge there have been no double-blind studies investigating the effects of DHA-rich fish oil on blood lipid concentrations. Therefore, we conducted a placebo-controlled double-blind study. Twenty-four healthy, normolipidemic young adults took either DHA-rich fish oil capsules containing 1.5-1.8 g of DHA or control oil capsules containing 97% soybean oil and 3% fish oil for 13 wk. Blood samples were taken at the start and end of the study, and serum lipids concentrations were compared. There were no significant changes over time in the DHA group in the following serum lipids: total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, lipoprotein(a), and apolipoproteins A1 and B. In contrast, apolipoprotein A1 concentrations slightly (10%) but significantly increased over time in the control group. Docosahexaenoic acid at a dose of less than 2 g/d did not change serum lipid concentrations of normolipidemic subjects. The effects of DHA in hyperlipidemic patients remain to be investigated in a double-blind study.