The difficultly extractable lipides of cottonseed meats,their composition and effect on the refining characteristics of the crude oils

Summary and Conclusions Crude lipides fractions were produced from raw, tempered, and cooked meats from two lots of cottonseed by a series of successive stepwise extractions, designed to obtain fractional portions of the total lipides in the order of the difficulty of their extraction. The proximate composition of the crude lipides fractions was determined. It was found that the composition of successive lipides fractions varied with the degree of exhaustiveness of extraction. The fractions obtained by more exhaustive extraction contained greater amounts of undesirable non-neutral oil material and lesser amounts of desirable neutral oil. It was also established that the method used in preparing meats for extraction was of paramount importance in its effect on the composition of the crude lipides obtained. The crude lipides fractions from raw and tempered meats contained large amounts of impurities while the crude lipides fractions similarly obtained from cooked meats were relatively low in impurities. Crude oils equivalent to varying degrees of total lipides extraction were reconstituted from the crude lipides fractions and evaluated for refining characteristics. The impurities content of the reconstituted oils varied as the degree of total lipides extraction and increases in the impurities content of the oils were generally reflected in disproportionate increases in refining losses and/or refined oil color. The oils obtained from the cooked meats at all degrees of extraction were outstandingly low in refining losses as compared to the oils from the raw and the tempered meats. Presented in two parts at the spring meeting, American Oil Chemists’ Society, New Orleans. La., Apr. 18–20, 1955, and at the fall meeting, Philadelphia, Pa., Oct. 10–12, 1995. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Selective hydrolysis of soybean oil phosphatides

Summary A rapid method is described for treating nondegummed soybean oil with water and a mixture of cation and anion exchange resins at elevated temperatures. In less than 30 min. 85% of phosphatide phosphorus is converted to a water-soluble, petroleum ether-insoluble form. Very little free or combined fatty acids are associated with the phosphorus thus split off from the phosphatide, and only a moderate increase in free fatty acid in the oil phase occurs. It is proposed that the phosphatides are largely converted to diglycerides by the selective hydrolytic treatment. Presented at the 49th Annual Meeting, American Oil Chemists' Society, Memphis, Tenn., April 21–23, 1958.     

Factors promoting the formation of nonhydratable soybean phosphatides

Whole, cracked and flaked soybeans were stored under a variety of conditions. After extraction with hexane, the crude oils were degummed in the laboratory, and the nonhydratable phospholipid (NHP) content was estimated from the phosphorus content of the degummed oil. Results showed that four interrelated factors promote NHP formation. These include (i) moisture content of beans or flakes entering the extraction process; (ii) phospholipase D activity; (iii) heat applied to beans or flakes prior to, and during, extraction; (iv) disruption of the cellular structure by cracking and/or flaking. Results from this study suggest that NHP formation can be minimized by control of the moisture of beans and/or flakes entering the extraction process, inactivation of phospholipase D enzyme, and optimizing temperatures during the conditioning of cracked beans or flakes. Presented at the 82nd Annual Meeting of the American Oil Chemists’ Society, Chicago, IL, May 12–16, 1991.     

About the conversion factor of phosphorus to phosphatides in soybean oil

The factor of 30 recommended by the official AOCS method Ca 12-55 for converting phosphorus to phosphatides in soybean oil is in reality a conversion factor to “acetone insolubles.” While applicable to crude soybean oils, its applications to degummed and refined oils is open to question. A corresponding revision of the method Ca 12-55 seems therefore indicated.     

Origin of the nonhydratable soybean phosphatides: Whole beans or extraction?

Whole soybeans and flakes, tempered to normal (10%) and elevated (14%) moisture levels, were stored and then extracted under a variety of conditions in both the presence or absence of phospholipase activity. Crude oils were degummed, and the resulting nonhydratable phosphatide (NHP) content was determined. Extractions performed on flakes at ambient temperature or at the boiling point of hexane showed that at normal (10%) moisture levels the temperature of extraction had little effect on the magnitude of NHP formation; whereas at 14% moisture, considerably higher levels of NHP were observed at the higher extraction temperature. Studies performed with 10- and 14%-moisture whole beans stored at 40°C for extended periods, with or without inactivation of enzymes, showed that at normal 10% moisture levels little deterioration occurs after one week of storage; however, after four weeks considerable NHP is formed. At 14% moisture, NHP formation was rapid during the first week of storage, and complete destruction of the phospholipid occurred after four weeks’ storage at 40°C. The results of these experiments indicate that the adverse effects of storage conditions, excessive moisture levels and elevated temperatures cannot be overcome by inactivation of phospholipase D prior to solvent extraction of the flakes.     

Preferential degradation of noncholine phosphatides in soybean lecithin by thermalization

Purified soybean lecithin and the gum derived from soybean oil processing were heated separately in bulk at 125 to 200°C for 60 min, or at 175°C for 30, 60, 90 and 120 min, and the products were analyzed by thin-layer chromatography and high-performance liquid chromatography. It was found that the noncholine phosphatides are preferentially degraded relative to phosphatidylcholine, and that these phosphatides are broken down in the order phosphatidyl-ethanolamine (PE)>phosphatidylinositol (PI)>phosphatidic acid (PA) with increasing temperature. At 175°C, the heating time required to degrade the noncholine phosphatides was between 30 and 60 min. Diglycerides were the principal products of thermalization at 77% of the total material, indicating that the 3-phosphoester linkage is the most heat-labile portion of the noncholine phosphatide molecules. Cleavage of the fatty acids from positions 1 and 2 of the phosphatides was minimal, as indicated by the relatively low amount of free fatty acids (8% of the total) when the lecithin was heated at 180°C for 90 min. The appearance of brown discoloration, characteristic of heated lecithin, coincided mainly with the decomposition of PE.     

The direct alcoholysis of suprarenal phosphatides

Previous attempts to directly prepare methyl esters from phosphatides failed apparently because not enough HCl was present as catalyst. In the present work suprarenal phosphatides were directly converted into esters by alcoholysis with methyl, ethyl, propyl, butyl and amyl alcohols using 5.0% HCl and 7.5 and 12.0% H₂SO₄ as catalysts. The process of esterification is greatly simplified by this procedure.     

Separation by dielectric distribution: Application to the isolation and purification of soybean phosphatides and bacterial spores

The redistribution of particle suspensions which occurs in a nonuniform electric field was used to separate soybean phosphatide micells from crude soybean miscella. Two arrangements of the nonuniform field were used. This method provides a convenient laboratory method for isolating and concentrating polar lipids. At present the method is too slow for commercial application but this may become feasible with improvements in apparatus design. A simple apparatus was described that gave efficient separation of bacterial spores from vegetative cells. Journal Paper No. J-4951 of the Iowa Agricultural and Home Economics Experiment Station, Ames, Iowa Project No. 1517.     

Improving the fatty acid composition of soybean oil

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

The fats and phosphatides in grass

Conclusion The analysis of grass, in a dry state, proved that it contains a rather high amount of fat and fat-like products, phosphatides and waxes; the total quantity is over 7%. Most of the phosphatides can only be extracted with a solvent mixture containing alcohol. There is no doubt that really true phosphatides can be separated, but it seems that other P-containing organic compounds are present in small quantities. The total amount of phosphatides is at least 0.5% in the dry grass. I desire to express my thanks to Mr. Charles M. Caines who has been of great assistance in conducting a good deal of the experimental analytical work connected with this research.     

The effect of soybean moisture during storage on the lipid composition of extracted crude oil

The quality of soybean oil extracted from seed stored under constant temperature and relative humidity for 42 days was evaluated over a wide range of moisture levels. Storage of soybeans at 9, 13 and 18% moisture had little affect on the major lipid components (neutral lipids), even though seed stored at 18% moisture became infected with mold. The level of phospholipid in the extracted crude oil decreased during the last 3 weeks of storage in seeds stored at 13 and 18% moisture from 4 to 2.5% of the total oil. During the same period, the level of free fatty acids, (FFA) (primarily 16∶0 and 18∶2) in these samples increased. This study indicated that the increase in FFA during seed storage at high moisture levels was the result of soybean lipase and possibly phospholipase activity. These findings suggested that soybeans should be kept at less than 13% moisture for long-term on-farm storage to preserve oil quality.     

Alteration of soybean oil composition by plant breeding

Experimental lines selected from the cross PI 90406 × PI 92567 are being used in an attempt to improve soybean (Glycine max [L.] Merr.) oil by altering fatty acid composition through plant breeding. Preliminary evidence shows that the concentration of linolenic acid in soybean oil is reduced by selection for high levels of oleic acid. Levels of poly-unsaturated acids in “high oleic” selections are lower, to various degrees, but the concentration of saturated fatty acids is not different from that of the variety Dare, a representative southern commercial cultivar. In triglyceride from the “high oleic” selection, N70-3436, levels of palmitic, stearic, oleic, linoleic, and linolenic acid are 9.5, 2.0, 40.1, 43.3, and 5.1 mol %, respectively. The types of triglyceride structures observed in the experimental lines which were examined also are changed. The combined level of triolein, monooleyl-dilinolein, and dioleyl-mono-linolein in seed from N70-3436 is doubled and constitutes ca. 50% of the oil.     

Sterol composition during the life cycle of the soybean and the squash

Sterol analyses were performed on soybeans and squash at intervals throughout the life cycle from seed to mature seed-bearing plant. The sterols of the soybean (24-methyl-cholesterol, stigmasterol and sitosterol) increased in quantity from that in the seed in each stage examined except for a pause or decrease prior to flowering and a decrease at senescence. Individual sterols remained in the same proportion to each other and changes in content were similar in roots and shoots. In the squash a much more complicated sterol mixture was found, composed primarily of C-7 unsaturated sterols characteristic of Cucurbitaceae. Sterol composition also increased during the life cycle except for approximately two wk in the preflowering to early flowering period. The data indicate low synthesis or high turnover of sterols (or both) in these plants in the weeks at or just prior to flowering.     

The oil and phosphatides content of some petals and stamens

Conclusion It was found that the petals of all plants investigated contained considerable quantities of phosphatides and that stamens also contained considerable amounts. The oils obtained from these plant organs, as well as the oil of unripe poppy seeds, varied considerably in consistency from ordinary seed oils. I am indebted to Mr. Charles M. Caines for the analyses of many of the raw materials and finished products.     

The centrifugal acetone foots test applied to crude soybean oil. II. Rapid method compared with other measures of phosphatides content and refining loss

Summary Comparisons are made between eight methods of grading crude soybean oil with respect to a laboratory refining loss determination which closely simulates commercial wash kettle practice. This list of methods includes the five analysis factors, acetoneinsoluble, HCl heat break, centrifugal foots, phosphorus and ash contents, each combined with percentage of ffa and moisture and volatile. It includes the official A.O.C.S. cup loss, the Wesson loss, and the chromatographic absorption loss determinations. On 12 crudes on which laboratory wash extraction loss and losses determined from centrifugal foots values, from acetone-insoluble contents, and from HCl break values were available, the centrifugal foots values best predicted the refining loss. The standard deviations of each method from the wash extraction loss were, respectively, 0.21%, 0.27%, and 0.29%. On seven of these crudes on which all nine determinations were available, acetone insoluble content showed the best correlation, followed by centrifugal foots and HCl heat break. The centrifugal foots test generally gives zero or trace results on degummed oil. By use of this method however the refining loss grade of crude soybean oils may be estimated in as little as one hour of elapsed time, and it requires only 5 to 10 minutes of the operator's time.     

Studies on the antioxygenic properties of wheat germ phosphatides

Summary 1. In accelerated stability tests wheat germ phosphatides were shown to prevent the accumulation of peroxides in both fresh and partially oxidized wheat germ oil. 2. The phosphatides as well as phosphoric acid apparently reacted with fatty peroxides to form complex polymeric substances. 3. Oxygen absorption by highly purified wheat germ phosphatides proceeded without the accumulation of titratable peroxides and without the liberation of free (water-extractable) phosphoric acid. Polymers appeared to be the chief product of the oxidation. Journal Paper No. 682 of the Purdue University Agricultural Experiment Station, Lafayette, Ind.