Acylglycerol structure of genetic varieties of peanut oils of varying atherogenic potential

Detailed investigation was made of the triacylglycerol structure of three varieties of peanut oils of varying atherogenic activity. By means of chromatographic and stereospecific analyses, it was shown that all the oils had markedly nonrandom enantiomeric structures with the long chain saturated fatty acids (C₂₀−C₂₄) confined exclusively to thesn-3-position, whereas the palmitic and oleic acids were distributed about equally between thesn-1-andsn-3-positions, with the linoleic acid being found preferentially in thesn-2-position. On the basis of detailed studies of the molecular species of the separatesn-1,2-,sn-2,3- andsn-1,3-diacylglycerol moieties, it was concluded that the fatty acids in the three positions of the glycerol molecule are combined with each other solely on the basis of their relative molar concentrations. As a result, it was possible to calculate the composition of the molecular species of the peanut oil triacylglycerols (including the content of the enantiomers and the reverse isomers) by means of the 1-random 2-random 3-random distribution. In general, the three peanut oils possessed triacylglycerol structures which where closely similar to that derived earlier for a commercial peanut oil of North American origin. Since their oil has exhibited a high degree of atherogenic potential, it was anticipated that the present oils would likewise be atherogenic, which has been confirmed by biological testing. However, there are certain differences in the triacylglycerol structures among these oils, which can be correlated with the variations in their atherogenic activity. The major differences reside in the linoleic/oleic acid ratios in the triacylglycerols, especially in thesn-2-position, and in the proportions in which these acids are combined with the long chain fatty acids. On the basis of the characteristic structures identified in the earlier analyzed atherogenic peanut oil, the peanut oil of South American origin would be judged to possess the greatest atherogenic potential and this has been borne out by biological testing.     

Lipolysis of corn,peanut and randomized peanut oils

Corn oil, peanut oil and randomized peanut oil exhibit different atherogenic potentials; peanut oil being more atherogenic than the other oils. This study was conducted to ascertain if the atherogenicity of these oils was related to their rates of lipolysis. Using both pancreatic lipase and milk lipoprotein lipase (LPL), it was shown that the rated of lipolysis were corn oil>peanut oil>randomized peanut oil. The rates of lipolysis are not related to atherogenicity and may be affected by the distribution of long-chain saturated fatty acids in the component triglycerides.     

Glycerolysis of peanut and mustard oils

Summary The glycerolysis of peanut and mustard oils has been carried out in the presence of catalysts such as lime and litharge. The effect of time and temperature on the rate of glycerolysis has been studied. The monoglyceride contents and hydroxyl values of the washed samples have been determined. The diglyceride and triglyceride contents of the products have been computed from the monoglyceride percentage and the hydroxyl values.     

Genetic studies of peanut proteins and oils

Journal of the American Oil Chemists' Society - Six peanut cultivars (Chico, Argentine, Tennessee Red, Florunner, F334A-B-14, and Florida Jumbo) and their F2 seed populations were used to...     

Antioxidant efficacy of methanolic extracts of peanut hulls in soybean and peanut oils

Antioxidant activity of methanolic extracts of peanut hulls (MEPH) was evaluated in soybean and peanut oils after accelerated oxidation at 60°C. Results showed that the oils with 0.12, 0.48, and 1.20% MEPH had significantly (P<0.05) lower peroxide values and acid values than the control after storage at 60°C. Moreover, oils with 0.48 and 1.20% MEPH were significantly (P<0.05) superior to 0.02% butylated hydroxyanisole (BHA) in reducing oxidation of both oils. Negative synergism was observed when 0.48 and 1.20% MEPH were mixed with 0.01% dl-α-tocopherol or 0.01% BHA in soybean oil compared to MEPH alone.     

Evaluation of peanut and cottonseed oils for deep frying

A comparative study of cottonseed and peanut oils for frying of potato chips was undertaken. Industrial scale frying was conducted for 5 days with cottonseed and 5 days with peanut oil and frying oils and chips were sampled twice a day. Frying oils and oils extracted from stored chips were analyzed for ultraviolet absorption (A₂₃₂ and A₂₆₈), peroxide and acid values. Tocopherol and tertiary butylhydroquinone levels were determined by high performance liquid chromatography. Chips stored at room temperature for 12 weeks were organoleptically evaluated. During the first 20 hr frying the A₂₃₂, free acid and peroxide values of cottonseed oil increased rapidly, exceeding that of peanut oil, which increased moderately. For both oils, constant values were attained during the next 80 hr period, followed by moderate increases during the last 23 hr. Peanut frying oil lost 55% of its tocopherols and 54% of its tertiary butylhydroquinone during frying (103 hr), whereas cottonseed frying oil retained these compounds at the original levels. Tocopherols were also better retained in chips fried in cottonseed oil than in peanut oil. The fatty acid patterns of frying oils and oils extracted from chips did not show significant changes due to frying and storage, respectively. These results, therefore, suggest that cottonseed oil is sufficiently stable to be used as a substitute for peanut oil in deep frying.     

Comparison of oxidative stability of high- and normal-oleic peanut oils

A peanut breeding line with high-oleic acid and an isogenic sister line with normal fatty acid composition were obtained. Oil was extracted with dichloromethane and processed in the laboratory by alkali neutralization and bleaching. Fatty acid compositions were determined by gas chromatography and application of theoretical response factors. Oils were extracted and processed in duplicate. The oxidative stability of the oils was measured by the Schall oven test (80°C), active oxygen method (AOM) (112°C) and by comparison of oxidation rates on thin-layer chromatography-flame ionization detector (TLC-FID) rods (100°C). Fatty acid analysis indicated that the high-oleic line had 75.6 and 4.7% oleic and linoleic acids, respectively, compared to 56.1 and 24.2% for the normal line. The induction times for the Schall test were 682 and 47 h for high- and normal-oleic oils (P<0.01). The AOM induction times were 69 and 7.3 h for high and normal oils, respectively (P<0.01). The times to reach 50% loss in triglyceride area on TLC-FID were 847 and 247 min for high-oleic compared to normal-oleic oils (P<0.01). The results indicate that high-oleic peanut oil has much greater autoxidation stability as compared to normal oil.     

Organoleptic and oxidative stability of blends of soybean and peanut oils

A table oil or a salad and cooking oil must serve both as an oil for salad dressings and for cooking potatoes in a deep-fat fryer. Blends of peanut and unhydrogenated soybean oil that have been treated with a metal inactivating agent such as citric acid were scored fairly high by a research taste panel after aging for 4 or 8 days at 60 C. Heating the samples to frying temperature resulted in significantly higher room odor scores for peanut oil than for the blends. Blends of hydrogenated or hydrogenated-winterized soybean oil with peanut oil were generally scored about equal to peanut oil in room odor tests. Potatoes fried in these oils were generally given comparable and not significantly different scores. Presented at AOCS Meeting, Houston, May 1971. Northern Marketing and Nutrition Research Division, ARS, USDA.     

Varietal differences in peanut triacylglycerol structure

Stereospecific analysis of triacylglycerols from six peanut varieties showed diversity in percent fatty acid placement. Distribution of the fatty acids among thesn-1,-2 and-3 positions was clearly nonrandom. The percentages of palmitic and stearic acids, generally very low at thesn-2 position, were more predominant at thesn-1 than thesn-3 position. Long chain fatty acids were located almost exclusively at thesn-3 position. Thesn-2 position of all varieties was high in unsaturated fatty acids. Triacyglycerols were sufficiently different to suggest that concentrations of specific triacylglycerol species may vary with variety. Mention of firm names or trade products does not imply that they are endorsed or recommended by the Department of Agriculture over other firms or similar products not mentioned.     

Computation of conversion factors to determine the phospholipid content in peanut oils

Peanut oil was separated into the various lipid classes by column chromatography. The polar lipid fraction which contained phospho-lipids was separated into individual major components by 2-dimen-sional thin layer chromatography. Conversion factors for calculating the concentration of total phospholipid in peanut oil from percent elemental phosphorus were determined by estimation of molecular weights for the respective components. A conversion factor of 23.6, 24.8, 26.6, 22.2, and 24.4 was found for phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, phosphatidic acid, and total phospholipid, respectively. These factors also were used to convert µg of phosphorus into µg of phospholipid.     

Spectrophotometric estimation of soybean oil in admixture with cottonseed and peanut oils

Conclusion A spectrophotometric method has been described for the determination of soybean oil in admixture with cottonseed oil. The method provides a simple and rapid means of detecting gross adulteration of one oil with another and permits an accurate determination of linolenic acid for use as a criterion of the economic value of an oil mixture and as a guide in oil processing. The factor limiting the precision of the method is variation in composition of the cottonseed and soybean oils in the mixtures to be analyzed. Variations in composition affect the proportion of measured triene conjugation, due to the linolenic acid content of the soybean oil and the apparent linolenic acid content of the cottonseed oil. Thus, for unknown mixtures only average value corrections can be made for apparent linolenic acid content and the accuracy of a particular analysis will depend upon how well the composition of the oils in the particular mixture follows those of the average mixture. The method described can be extended to mixtures other than those of soybean and cottonseed oils. Thus, soybean oil may be determined in admixture with a peanut oil. In general, any oil which has an unsaturated fatty acid capable of producing triene conjugation upon alkali isomerization can be determined in the presence of any other oil containing no appreciable quantity of unsaturated fatty acids which can produce triene conjugation by such treatment. Presented before The American Oil Chemists’ Society, New Orleans, Louisiana, May 10–12, 1944. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Triacylglycerol structure of an african peanut oil

Triacylglycerols were isolated from an African peanut oil, then fractionated by unsaturation into classes, and the triacylglycerol structure was determined on these classes using pancreatic lipase hydrolysis. Fatty acid analysis of monoacylglycerols and, in some cases, of 1 or 2 classes of diacylglycerols, allowed the proportions of 84 isomers to be calculated. The oil had a high oleic acid content (60.3%) and contained nearly 25% of trioleoylglycerol, the major triacylglycerol. The 4 most abundant isomers together represented more than one-half of the total triacylglycerols. In 30 isomers, the 2-position was occupied by linoleic acid, and in 39 isomers, by oleic acid. The very long-chain saturated fatty acids (20:0, 22:0, 24:0) that formed 5.1% of the fatty acid content of the oil, were not found in the 2-position. In most cases, each was associated with 2 molecules of an unsaturated fatty acid. The placement of fatty acids, respectively, at the 1,3-position and the 2-position was relatively close to a l,3-random-2-random distribution, except for trioleoylglycerol (24.7% instead of 21.7% by the random hypothe-sis). To whom requests should be sent.     

原子吸收测定甘油脂中钠的含量

通过对溶样时间、酸度的选择,以及工作曲线法与标准加入法的比较,介绍了甘油脂中钠含量的测定方法。样品经硝酸加热溶解、稀释、过滤,原子吸收分光光度计测定,实验数据表明:分析方法结果准确,其相对标准偏差为2.3%～2.8%,回收率为97%～101%,可用于甘油脂产品中钠的分析检测工作。     

Possibilities of peanut,pecan and safflower seed oils as supplements for olive oil

Summary Samples of completely refined peanut oil, semirefined pecan oil, imported edible grade olive oil and crude safflower seed oil have been examined for composition, spectral transmittance and other properties. Compositions were determined by means of the modified Bertram oxidation method and application of the iodine-thiocyanogen number technique. None of the oils examined simulate olive oil in composition. Peanut and pecan oils appear capable of modification to produce a product chemically similar to olive oil and for certain purposes can replace olive oil without modification. The production of pecan oil under present market conditions with regard to prices for edible oils and seedling pecan nuts does not appear to be very attractive unless the costs of processing pecans for oil can be greatly reduced. Presented before the American Oil Chemists’ Society Meeting, Houston, Texas, April 30 to May 1, 1942.     

Phase relations pertaining to the solvent winterization of cottonseed and peanut oils in acetone

Summary and Conclusions Systematic physical chemical data on the solventwinterization behavior of cottonseed and peanut oils with acetone have been obtained which should serve as a basis for selecting the conditions necessary for the effective solvent winterization of these oils in acetone. Cottonseed and peanut oils are only partially miscible with acetone below certain temperatures which have been determined. In peanut oil this phenomenon may interfere with the winterization process within a certain range of concentrations. For cottonseed oil however the separation into two liquid phases does not occur until some 5°C. below the temperature required for adequate winterization. Complete data for a 3-hour holding-time have been obtained for three cottonseed oils ranging in iodine value from 106.1 to 116.4. Tables and graphs have been constructed to show the effect of oil-solvent ratio, chilling temperature, holding-time, agitation, and iodine value of the original oil on the percentage of solid removed and on the degree of winterization and iodine value of the winterized oil. Similar data have been obtained for a refined peanut oil insofar as possible without interference from separation into two liquid phases. It seems probable that if acetone were used as the winterization solvent for peanut oil, the separation into two liquid layers and the sensitivity of this phenomenon to moisture might be a source of processing difficulties especially if filtration instead of centrifugation were used to separate the solid from the supernatant. Resigned: September 2, 1949. Resigned: August 13, 1948. Resigned: January 28, 1949. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Alcoholic extraction of vegetable oils. I. Solubilities of cottonseed,peanut, sesame,and soybean oils in aqueous ethanol

Summary Solubilities of cottonseed, peanut, sesame, and soybean oils in aqueous alcoholic solutions at various temperatures were determined directly. Solubility curves for the four oils in aqueous alcoholic solutions are presented. The critical solution temperaturesversus alcoholic concentrations data have been plotted and are in complete agreement with the previously published data of Japanese workers in each case. It is observed that the critical solution temperature increases with the moisture content of the alcohol, and in each case the relationship is linear. The pressure in the system also varies directly with the temperature, the maximum being approximately 20 p.s.i.g.