Effect of alleles governing 16:0 concentration on glycerolipid composition in developing soybeans

Soybean [Glycine max (L.) Merr.] oil typically contains 11% palmitic acid, but germplasm with recessive alleles at Fap gene loci exhibit from less than 4% to about 35% 16:0, Although these alleles are used to develop new cultivars, little is known about how they influence palmitic acid concentration. One theory suggests that fap alleles may mediate differences in triacylglycerol composition through genetic effects on the activity or substrate specificity of acyltransferases, such as diacylglycerol acyltransferase (EC 2.3.1.20). Based on logistic function analysis of developing seed, differences in fag allele expression are evident in the rate of palmitic acid accumulation in triacylglycerol, with peak deposition near mid-seed fill. Acetate saturation kinetics also reveal a strong positive relation between the relative amount of de novo palmitic acid synthesis and the indigenous palmitic acid concentration in triacylglycerol among fap genotypes. However, no differences appear in the kinetics of palmitoyl-CoA metabolism in developing seed of these genotypes. Therefore, the fap alleles apparently do not encode or regulate the activities of glycerolipid acyltransferase enzymes. Rather, major genetic effects on triacylglycerol composition accrue through regulation of palmitic acid production in the plastids of developing soybean cotyledons.     

Changes in the composition of soybeans on sprouting

Summary Changes in nitrogen and oil contents and loss in dry weight have been followed during the first six days of germination of the Hawkeye variety of soybeans; thiamin and ascorbic acid content have been followed for four days. During the first three days about 1.5% of the dry matter was lost; the nonprotein nitrogen increased from 3 to 6% of the total nitrogen, with no change in the petroleum ether extractables and with a decrease in free fatty acids. At the end of six days, with sprouts about 2 1/2 in. long, only 2.6% of the dry matter was lost, the nonprotein nitrogen had increased to 13% of the total nitrogen with 2.6% loss of total nitrogen, and a 12% loss was observed in petroleum ether extractables; the free fatty acids did not increase appreciably. No change in the thiamin content occurred during the first four days of germination. Ascorbic acid was found to be absent in mature beans but appeared after the start of germination and increased rapidly during the fourday period. An analysis of these results and of those from the literature indicates that soybeans sprouted for two to three days have possibilities for use in high-energy, high-protein broiler feed. Presented at the fall meeting, American Oil Chemists’ Society, Chicago, Ill., September 23–26, 1956.     

Effect of weather damage on the chemical composition of soybeans

Summary Soybean samples containing a large proportion of damaged seed were separated into sound and damaged portions and these portions were then analyzed chemically. Analysis of these samples indicated that damage to the seed caused considerable variation in percentages of oil, protein, ash, and in iodine number and acid of the oil. Sugars in the damaged portions of the soybean samples were generally low when compared with the sound portions. Weather damaging of soybean seed caused a marked increase in percentage of crude protein. Oil percentages were sometimes higher and sometimes lower in the damaged portions. The iodine number of the oil was usually but slightly affected, and the acid number was higher in the damaged portions. In order that the chemical analysis of the samples may be representative of the true composition of a strain, the seed analyzed should be of good quality and contain no more than a small proportion of damaged seed. A publication by the U. S. Regional Soybean Laboratory, a cooperative organization participated in by the Division of Forage Crops and Diseases, Bureau of Plant Industry, Soils, and Agricultural Engineering. Agricultural Research Administration, U.S.D.A. and the Agricultural Experiment Stations of Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Nebraska, North Carolina, North Dakota, Ohio. Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Virginia, Wisconsin.     

The plant geneticist’s contribution toward changing lipid and amino acid composition of soybeans

Interest in changing composition of soybeans focuses on linolenic acid in the oil. Available germ plasm includes no lines with less than about 3.5% linolenic acid in the oil. Some breeding lines have been obtained with iodine values of about 115, reflecting higher oleic acid and somewhat lower than normal linoleic and linolenic acid levels. Radiation and other mutagenic agents have been investigated to a limited extent for potential usefulness in inducing a mutation in the direction of low linolenic acid. No such mutant has yet been found, and the task of identifying one is formidable. There is no research known at this time with the objective of altering amino acid distribution in soybeans. One of seven papers presented at the Symposium, “The Plant Geneticist’s Contribution Toward Changing the Lipid and Amino Acid Composition of Oilseeds,” AOCS Meeting, Houston, May 1971.     

Studies on the glycolipids and phospholipids of immature soybeans

The lipid of immature soybeans was extracted with chloroform-methanol and fractions containing the glycolipids and phospholipids were separated by column chromatography. Phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), phosphatidyl inositol (PI), phosphatidic acid (PA) phosphatidyl glycerol (PG), n-acyl phosphatidyl ethanolamine (APE) and sulfolipid (SL) were identified by thin layer chromatography (TLC). Sterol glucoside (SG), esterified sterol glucoside (ESG), digalactosyl diglyceride (DGDG) and cerebrosides (CE) were isolated by TLC and identified by color reactions, chemical degradation and spectral analysis.     

Studies on lipid and fatty acid composition of human hepatoma tissue

Studies are reported on the composition of the lipids of human liver and hepatoma tissues from male adults. Liver tissues were obtained from individuals who died from causes other than liver disease or cancer. The hepatoma tissues were obtained from individuals shortly after they succumbed to cancer. The total lipid of each tissue was fractionated quantitatively by silicic acid column chromatography into neutral lipid, glycolipid, and phospholipid fractions. These fractions were analyzed by thin layer chromatography and converted to methyl esters for analysis of their constituent fatty acids by gas liquid chromatography. In comparison to liver tissue, the total amount of lipid in the hepatoma tissues was generally higher and more variable; the lipid of one hepatoma was ca. 92% of the dry wt of the tissue. The greater lipid content of the hepatoma tissues was due to the high percentage of neutral lipid. Except for one specimen, there was ca. the same amount of glycolipid in the hepatoma as in the liver tissues, but the composition of the glycolipid fraction of the hepatoma lipid differed considerably, particularly in the ganglioside fraction. The phospholipid fraction of hepatoma lipid was much lower than that of liver but exhibited only quantitative differences in composition. No glyceryl ether diesters and only traces of plasmalogens of phosphatidyl choline or phosphatidyl ethanolamine were detected in the liver and hepatoma lipids. The levels of monoenoic acids were higher and those of linoleic and polyunsaturated fatty acids lower in the hepatoma lipids. Positional isomers of trienoic acids not normally present in liver tissue were detected in hepatoma lipids. The abnormalities observed in lipid composition indicated interferences in the regulatory processes of lipid metabolism in human hepatoma similar to those observed in animals.     

Studies on the changes in fatty acid composition in developing seeds. I.

Oils from castor seeds at different stages of ripening have been studied. The fatty acid composition has been determined by paper chromatography. The ratio of the weight of the kernel to the weight of the seed coat changes from 1.0: 1.24 (14 days) to 1.0:0.48 (45 days) and the oil content of the seed coat is negligible. Amounts of the individual fatty acids in 1 g of kernel as well as in a single seed have been shown. The amounts of ricinoleic, linoleic and stearic acids gradually increase with the ripening of the seeds whereas the amounts of oleic and palmitic acid after an initial increase upto 28 days gradually decrease towards the later stages of growth when the amounts are calculated on the basis of a single seed.     

Fatty acid composition of several varieties of soybeans

Summary Fatty acid composition of soybean oil of 18 currently important varieties from 43 locations in 16 states of the United States ranged from about 5% to 11% in linolenic, 43% to 56% in linoleic, 15% to 33% in oleic, and 11% to 26% in saturated acids. Oil of all 18 varieties had wide ranges in composition at different locations in two crop years. Within each group varieties tended to maintain the same relative order of fatty acid compositions of oil at all locations in the two years of this study. Publication No. 326 of the U. S. Regional Soybean Laboratory, Urbana, Ill.     

Effect of fungal damage on seed composition and quality of soybeans

Fungal damage caused by pathogens such asFusarium, Cercospora, andPhomopsis can have a devastating impact on physical quality and farm price of soybeans. In some price-discount schedules, soybeans may be rejected with as low as 5% fungal damage. Although the severity of this problem varies throughout the United States, millions of bushels of fungus-damaged soybeans may be destroyed annually due to a lack of markets. The effect of fungal damage on seed composition was evaluated to assess potential utility of highly damaged soybeans. Graded samples of the cv. Centennial soybean were dried to 10% moisture and blended on a proportional weight basis to derive a series of treatments from 0 to 80% fungal damage. A positive correlation was found between fungal damage and both protein and oil concentrations. This condition was attributed to loss of residual seed mass. As a result, the protein concentration of defatted meal increased from ca. 54 to 66% over the range of 0 to 80% fungal damage. Mycotoxin contamination appeared to be insignificant in these high-protein meals. Fixed colors in bleached, alkali refined oils were intensified by heat treatment prior to extraction. No significant differences, however, were noted in total polar lipid content, phospholipid, or tocopherol composition among treatments of up to 20% fungal damage. Oils from treatments of more than 40% fungal damage were more severely oxidized and could not be degummed effectively. These data suggest that fungus-damaged soybeans may be blended with high-quality soybeans to alleviate the chemical symptoms associated with unacceptable product quality. Thus, through various blend ratios, processors may consider using fungus-damaged soybeans to gain economic advantage, especially when high-quality soybeans have lower protein concentration.     

Bis-phosphatidic acid in developing soybeans and soybean suspension cultures

A phospholipid which rapidly accumulates radioactivity from [1-¹⁴C] acetate administered to slices of developing soybeans or to suspension cultures of soybean cells was isolated. Its structure was identified by comparison of its properties and degradation products with those of authentic lipid standards using infrared absorption spectrometry, thin layer chromatography, acetolysis, mild alkaline hydrolysis, and determination of molar ratios of phosphorus, glycerol, and acyl moieties. The structure of the phospholipid was found to bebis-phosphatidic acid, a phospholipid previously unreported in higher plants.     

Temperature effects on tocopherol composition in soybeans with genetically improved oil quality

Tocopherol, a natural antioxidant, typically accounts for a small percentage of soybean (Glycine max L. Merr.) oil. Alleles that govern the expression of polyunsaturated fatty acids in soybean germplasm are influenced by temperature. However, little is known about the environmental influences on tocopherol expression. The objective of this study was to assess the influence of temperature on tocopherol composition in soybean germplasm that exhibit homozygous recessive and dominant alleles that govern the predominant ω-6 and ω-3 desaturases. The control cv. Dare and three low-18:3 genotypes (N78-2245, PI-123440, N85-2176) were grown under controlled-temperature environments during reproductive growth. Analysis of crude oil composition at various stages of seed development revealed a strong negative correlation between total tocopherol content and growth temperature. The relative strength of this correlation was greater in the germplasm that exhibited homozygous alleles governing the ω-6 desaturase than those governing the ω-3 desaturase. The decline in total tocopherol with reduced temperature was attributed predominantly to loss of γ-tocopherol. However, γ-tocopherol concentration also was directly related to 18:3 concentration in all genotypes. Thus, low-18:3 oils contained both a lower content and a lower concentration of γ-tocopherol. Although the biochemical basis for this observation is unknown, the antioxidant capacity of γ-tocopherol appeared to be directly associated with changes in oil quality that were mediated more by genetic than by environmental influences on 18:3 concentration. Another aspect of this work showed that low-18:3 soybean varieties should be expected to contain more α-tocopherol, especially when grown under normal commercial production environments. This condition should be regarded as another beneficial aspect of plant breeding approaches to the improvement of soybean oil quality.     

Phytic acid removal from soybeans by a lipid protein concentrate process

Over 90% of phytic acid has been removed from full-fat soy flour by a lipid-protein concentrate process previously reported in 1974 by the Northern Regional Research Center. In the current study, parameters for optimizing phytic acid removal were evaluated. By changing both the molar concentration of the calcium chloride solution used and the pH of the initial acid slurry, various amounts of phytic acid and mineral elements were recovered in the acid-precipitated curd. A mathematical treatment of the data using multiple regression analusis showed phytic acid removal possible from 10 to 90%, zinc recovery from 10 to 90%, and calcium concentrations equalling twice that of the original starting flour. All variable conditions introduced into the process had no effect on protein (90–93%), fat (98–100%), and iron (94–96%) recoveries. The results presented in this report can be applied to a large number of processes now being used for making edible soy proteins, and thereby low phytin-containing products can be acheived.     

Studies on the composition of some distillate waxes

Structural composition of two distillate waxes obtained from Ankleshwar crude oil tank bottoms have been determined using physical properties correlations, high temperature g.l.c., ¹H-n.m.r. and ¹³C-Fourier transform n.m.r. spectroscopy. Both waxes seem to contain predominantly n-paraffins.     

Phospholipid fatty acid composition and stereospecific distribution of soybeans with a wide range of fatty acid composition

Phospholipid (PL) fatty acid composition and stereospecific distribution of 25 genetically modified soybean lines with a wide range of compositions were determined by gas chromatography and phospholipase A₂ hydrolysis. Pl contained an average of 55.3% phosphatidylcholine, 26.3% phosphatidylethanolamine, and 18.4% phosphatidylinositol. PL class proportions were affected by changes in overall fatty acid composition. PL fatty acid composition changed with oil fatty acid modification, especially for palmitate, stearate, and linolenate. Stereospecific analysis showed that saturated fatty acids were primarily located at the sn-1 position of all PL, and changes of the saturates in PL were largely reflected on this position. Oleate was distributed relatively equally between the sn-1 and sn-2 positions. Linoleate was much more concentrated on sn-2 than on sn-1 position for all PL. Linolenate was distributed relatively equally at low concentration but preferred sn-2 position at high concentration.     

Color and the lipid composition of pork muscles

The lipid characteristics of three porcine muscles were investigated. Included in the study were the light and dark portions of the semitendinosus muscle, the semimembranosus (light) and the quadriceps femoris (dark) muscles. The lipids from the semimembranosus and the quadriceps femoris muscles were observed to be statistically different. The light muscles were 20% higher in lipid level and these lipids contained 20% more glycerides and 40% less phospholipids than the dark muscles. The glycerides from both muscle lipids were identical in fatty acid composition but the phospholipid fatty acids differed significantly. The light muscle phospholipid fatty acids were higher in monoenes while the dark muscle phospholipids predominated in polyunsaturates. In the semitendinosus muscle, the light portion was 35% higher in lipid content than the dark portion but the compositions of the lipids from both areas were similar. When these data were compared to the values for the semimembranosus and the quadriceps femoris muscle lipids, the lipid characteristics were found to be intermediate of predominantly light or dark muscle lipids. Presented at the AOCS Meeting, New York, October 1968. E. Utiliz. Res. Dev. Div., ARS, USDA.     

Carbon-13 nuclear magnetic resonance measurement of oil composition in single viable soybeans

High-resolution, natural abundance¹³C NMR spectra of intact, viable soybeans have been obtained by Fourier transform techniques. The spectra are interpreted in terms of the relative concentrations of the major fatty acids present in the soybean triglycerides. This nondestructive analysis is sufficiently fast and accurate to permit the selection of individual soybeans for use in a genetic breeding program designed to reduce the undesirably high linolenic acid content of soybean oil.     

Studies on the fatty acid composition of crayfish lipids

The fatty acid composition of carcass and exoskeleton lipids was determined for the freshwater crayfishOrconectes rusticus. Lipid fractions were isolated by column and thin-layer chromatography. Fatty acid methyl esters and alcohol acetates were then prepared and analyzed by gas-liquid chromatography. Peak identities were established from retention time data for methyl esters, hydrogenated methyl esters, and saturated, monoene, diene, and polyene methyl esters separated as acetoxy-mercuri-methoxy derivatives. Minor component acids were estimated from their relative compositions in these fractions. Presented at the symposium honoring J. B. Brown, AOCS meeting in Chicago, 1964.     

The effect of dietary fats on the plasma lipid composition of sheep

This study reports on the plasma lipid compositions of sheep fed either a control diet (C), a control diet supplemented with tallow (A) or polyunsaturated fatty acid (B) that had been protected against hydrolysis and hydrogenation in the rumen, or a control diet supplemented with maize oil (D). Diet B considerably increased the 18∶2 content of all the major plasma lipid fractions. Although the feeding of diet D also resulted in an increase in the 18∶2 contents within the cholesteryl ester, unesterified fatty acid, and phospholipid fractions the increases were considerably less than those observed with diet B; the levels of 18∶2 within the triglyceride fraction remained similar to that for the sheep which received the control diet. The effect of feeding diet A was confined solely to the triglyceride fraction where the concentrations of 16∶0 and 18∶1 were increased. The lipoproteins of the plasma were separated into very low density lipoproteins (d<1.006), low density lipoproteins (1.006<d<1.063), and high density lipoproteins (1.063<d<1.21), and the distribution of the major lipids between these lipoprotein fractions was investigated. Diet B increased considerably the proportion of triglyceride found in association with the very low density fraction and the concentrations of 18∶2 within all the lipoprotein fractions; these increases in the concentrations of 18∶2 were not confined to any particular lipid fraction of the lipoproteins. In contrast, the increases in the concentrations of 18∶2 produced as a result of feeding diet D were confined to the low and high density lipoproteins. The effect of feeding diet A was confined to fatty acid changes within the triglycerides of the low and very low density lipoproteins.     

Neutral and polar lipid phase transition of soybeans with various saturated fatty acid contents

Soybeans with modified saturated fatty acid compositions sometimes have lower seed germination rate or other undesirable agronomic traits. To determine if seed germination could be related to the melting transitions of their lipids, triacylglycerols (TAG) and phospholipids (PL) from soybeans with a wide range of saturated fatty acid compositions were examined by differential scanning calorimetry. The melting transition temperatures of both TAG and PL increased with increasing palmitate and stearate percentages. The mean melting points of the various lipids calculated on the basis of the melting points of their fatty acids correlated with the observed transition temperatures. Increased lipid saturation and elevated phase transition temperatures may have contributed to the reduced germination and seedling growth rates of these modified seeds.