R. Kleiman

Effect of temperature on soybean seed constituents: Oil, protein, moisture, fatty acids, amino acids and sugars

Soybean plants were grown at day/night temperatures of 24/19 C until the beginning of seed development, and then transferred to 5 different temperature regimes (18/13, 24/19, 27/22, 30/25 and 33/28 C) in the CSIRO phytotron. Mature seeds that developed under these conditions were analyzed for variances in composition. Fatty acid composition was strongly affected by temperature: linolenic and linoleic acids decreased markedly whereas oleic acid increased as the temperature increased; palmitic and stearic acids remained unchanged. Oil content was positively correlated with temperature, and protein content increased at the highest temperature. Of the sugars analyzed, sucrose concentration decreased by 56% with a 15 C increase in temperature, and stachyose showed a slight reduction; other sugars remained unchanged. Amino acid composition was generally stable; however, methionine increased with increased temperature during seed development. Moisture content was unaffected.

Homolytic decomposition of linoleic acid hydroperoxide: Identification of fatty acid products

An isomeric mixture of linoleic acid hydroperoxides, 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid (79%) and 9-hydroperoxy-cis-12,trans-10-octadecadienoic acid (21%), was decomposed homolytically by Fe(II) in an ethanol-water solution. In one series of experiments, the hydroperoxides were decomposed by catalytic concentrations of Fe(II). The 10−5 M Fe(III) used to initiate the decomposition was kept reduced as Fe(II) by a high concentration of cysteine added to the reaction in molar excess of the hydroperoxides. Nine different monomeric (no detectable dimeric) fatty acids were identified from the reaction. Analyses of these fatty acids revealed that they were mixtures of positional isomers identified as follows: (I) 13-oxo-trans,trans-(andcis,trans-) 9,11-octadecadienoic and 9-oxo-trans,trans- (andcis,trans-) 10,12-octadecadienoic acids; (II) 13-oxo-trans-9,10-epoxy-trans-11-octadecenoic and 9-oxo-trans-12, 13-epoxy-trans-10-octadecenoic acids; (III) 13-oxo-cis-9,10-epoxy-trans-11-octadecenoic and 9-oxo-cis-12, 13-epoxy-trans-10-octadecenoic acids; (IV) 13-hydroxy-9,11-octadecadienoic and 9-hydroxy-10,12-octadecadienoic acids; (V) 11-hydroxy-trans-12, 13-epoxy-cis-9-octadecenoic and 11-hydroxy-trans-9, 10-epoxy-cis-12-octadecenoic acids; (VI) 11-hydroxy-trans-12, 13-epoxy-trans-9-octadecenoic and 11-hydroxy-trans-9,10-epoxy-trans-12-octadecenoic acids; (VII) 13-oxo-9-hydroxy-trans-10-octadecenoic acids; (VIII) isomeric mixtures of 9, 12, 13-dihydroxyethoxy-trans-10-octadecenoic and 9, 10, 13-dihydroxyethoxy-trans-11-octadecenoic acids; and (IX) 9, 12, 13-trihydroxy-trans-10-octadecenoic and 9, 10, 13-trihydroxy-trans-11-octadecenoic acids. In another experiment, equimolar amounts of Fe(II) and hydroperoxide were reacted in the absence of cysteine. A large proportion of dimeric fatty acids and a smaller amount of monomeric fatty acids resulted. The monomeric fatty acids were examined by gas liquid chromatography-mass spectroscopy. Spectra indicated that the monomers were largely similar to those produced by the Fe(III)-cysteine reaction.

Search for new industrial oils: XVI. Umbelliflorae—seed oils rich in petroselinic acid

Seed oils of the order Umbelliflorae, including those from the families Umbelliferae, Garryaceae, Araliaceae, Cornaceae, Davidiaceae, Nyssaceae and Alangiaceae, were analyzed for fatty acid composition by gas liquid chromatography (GLC) of their methyl esters. The characteristic fatty acid of the order, petroselinic acid, occurred in the Umbelliferae in amounts up to 85%. In the Araliaceae, the content was as high as 83% and in the Garryaceae as high as 81%. The other major acids were palmitic, oleic and linoleic acids, with small amounts of hexadecenoic, stearic, linolenic, and, in some cases, C20 acids. petroselinic acid was determined by microscale ozonolysis of the C18 monoenoic esters and subsequent GLC of the ozonolysis products. The occurrence of high oil contents (up to 46%) combined with exceptionally high (up to 83%) single component purity is notable and emphasizes the potential of the Umbelliflorae as a raw material source for the chemical industry.

New sources of γ-linolenic acid

Abstractγ-Linolenic acid (18:3Δ6,9,12) occurs in significant amounts in various species of plants surveyed. Of the species analyzed in this study, Nonnea macrospernia, with 5.1% 7-linolenic acid in the seed, is the richest source of this fatty acid. Other species in the same family (Boraginaceae) are also good sources: Adelocaryum coelestinum, Alkanna froedinii, Alkanna orientalis and Brunnera orientalis. Scrophularia marilandica (family Scrophulariaceae) seeds contain 37.9% oil, of which 9.6% is γ-linolenic acid. All species mentioned above are better sources, when the total amount of γ-linolenic acid in the seed is considered, than that used traditionally, Evening Primrose (Oenothera biennis, family Onagraceae). None of the other Onagraceae nor any of the Ribes (family Saxifragaceae) species analyzed are as rich in γ-linolenic acid as Evening Primrose. Octadecatetraenoic acid (18:4Δ,6,9,12,15) was found in significant amounts in most of the Boraginaceae and Ribes surveyed. The Onagraceae and Scrophulariaceae lack detectable amounts of this fatty acid.

Effect of altered fatty acid composition on soybean oil stability

During the last 15 years, hybridization and induced mutation breeding of soybeans have been successful in producing an altered fatty acid composition in the extracted oil. The objective of those investigations was to produce a low-linolenic acid soybena oil. Crude oils extracted from the seeds of three such genotypes were processed in laboratory simulations of commercial procedures to finished deodorized oils. Analysis of the fatty acid composition of the three oils showed the linolenic acid content to be 3.3%, 4.2% and 4.8%. The stability of these finished oils was compared to that of oil from a soybean variety having a linolenic acid content of 7.7% and of a commercial hydrogenated-winterized soybean oil (3.0% linolenic acid). Test and control oils were evaluated by a trained sensory panel initially, after accelerated storage at 60 C and during use at 190 C in room tests. Peroxide values were determined at the time of sensory evaluation. Results indicated there was no significant difference in flavor stability during storage between test and control oils. There was no significant difference, between the oils, in peroxide development during accelerated storage. Compared to control oils, the test oils had improved overall room odor intensity scores and lacked the fishy odors of non-hydrogenated soybean oil and the hydrogenated odors of commercial cooking oil.

Triglyceride separation by reverse phase high performance liquid chromatography

Abstract and SummaryRapid separations of triglycerides by chain length and degree of unsaturation were made by high performance liquid chromatography (HPLC) on a C-18 μ-Bondapak column with acetonitrile-acetone solvent mixtures. For saturated triglycerides, a linear relationship was observed between the carbon number and the log of the retention volume. Each double bond present in the triglyceride decreased the retention volume to approximately that of a saturated triglyceride with two carbon atoms less. Correlations of the fatty acid composition, as determined by gas liquid chromatography (GLC) with the HPLC data, provides much additional insight about triglyceride composition. To calculate triglyceride compositions, an internal standard tripentadecanoin was added to collected fractions before analysis by GLC.

Formation oftrans-12,13-epoxy-9-hydroperoxy-trans-10-octadecenoic acid from 13-L-hydroperoxy-cis-9,trans-11-octadecadienoic acid catalyzed by either a soybean extract or cysteine-FeC13

A soybean extract or an ethanolic solution of cysteine and ferric chloride catalyzed the conversion of 13-L-hydroperoxy-cis-9,trans-11-octadecadienoic acid to numerous products among which wastrans-12,13-epoxy-9-hydroperoxy-trans-10-octadecenoic acid. When this fatty acid was treated further with the cysteine-ferric chloride solution, 9-hydroxy-12,13-epoxy-10-octadecenoic and 9-oxo-12,13-epoxy-10-octadecenoic acids were formed. Thus,trans-12,13-epoxy-9-hydroperoxy-trans-10-octadecenoic acid probably is an intermediate in the formation of the latter two compounds. Additionally, theerythro andthreo isomers oftrans-12,13-epoxy-11-hydroperoxy-cis-9-octadecenoic acid tenatatively were identified as products.

The triglyceride composition, structure, and presence of estolides in the oils ofLesquerella and related species

Members of the genusLesquerella, native to North America, have oils containing large amounts of hydroxy fatty acids and are under investigation as potential new crops. The triglyceride structure of oils from twenty-fiveLesquerella species in the seed collection at our research center has been examined after being hydrolysis-catalyzed by reverse micellar-encapsulated lipase and alcoholysis-catalyzed by immobilized lipase. These reactions, when coupled with supercritical-fluid chromatographic analysis, provide a powerful, labor-saving method for oil triglyceride analysis. A comprehensive analysis of overall fatty acid composition of these oils has been conducted as well.Lesquerella oils (along with oils from two other Brassicaceae:Physaria floribunda andHeliophilia amplexicaulis) have been grouped into five categories: densipolic acid-rich (Class I); auricolic acid-rich (Class II); lesquerolic acid-rich (Class III); an oil containing a mixture of hydroxy acids (Class IV); and lesquerolic and erucic acid-rich (Class V). The majority of Class I and II triglycerides contain one or two monoestolides at the 1- and 3-glycerol positions and a C18 polyunsaturated acyl group at the 2-position. Most Class III and IV oil triglycerides contain one or two hydroxy acids at the 1- and 3-positions and C18 unsaturated acid at the 2-position. A few of the Class III oils have trace amounts of estolides. The Class V oil triglycerides are mostly pentaacyl triglycerides and contain monestolide and small amounts of diestolide. Our triglyceride structure assignments were supported by1H nuclear magnetic resonance data and mass balances.

Search for new industrial oils. XI. Oils of boraginaceae

Analysis of seed oils from 29 species of the family Boraginaceae revealed widespread occur-rence of 6,9,12-octadecatrienoic and C18 noncon-jugated tetraenoic acids in addition to linolenic and other common C16 and C18 acids. The 6,9,12-octadecatrienoic acid ranged in amount from 0-27%, tetraene from 0-17%, and linolenic acid from 0.3-50%. Iodine values of the oils ranged from 88-225.

Search for new industrial oils. XII. Fifty-eight euphorbiaceae oils, including one rich in vernolic acid

Seed oil ofEuphorbia lagascae Spreng. contains 57% ofcis-12,13-epoxy-cis-9-octadecenoic (vernolic) acid. The amt of trivernolin in the glycerides of this species indicates random or restricted random distribution of the vernolic acid.Seed from 57 additional species in the Euphorbiaceae were analyzed for oil and protein contents and also for fatty acid composition of the oils. Iodine values (I.V.) of the oils ranged from 87–221. Among these oils, samples were encountered with as much as 76% linolenic, 77% linoleic or 84% oleic acid.