Ratios of Regioisomers of Triacylglycerols Containing Dihydroxy Fatty Acids in Castor Oil by Mass Spectrometry

The triacylglycerols (TAG) containing dihydroxy fatty acids have been recently identified by mass spectrometry in castor oil. These new dihydroxy fatty acids were proposed as 11,12-dihydroxy-9-octadecenoic acid (diOH18:1), 11,12-dihydroxy-9,13-octadecadienoic acid (diOH18:2) and 11,12-dihydroxyoctadecanoic acid (diOH18:0). The ratios of regioisomers of the TAG were estimated by fragment ions from the loss of fatty acids at the sn-2 position as α,β-unsaturated fatty acids by electro spray ionization-mass spectrometry of the lithium adducts (MS³). The content of regioisomeric diOH18:1-OH18:1-diOH18:1 (ABA, with two different fatty acids) was about 92% in the total of stereoisomeric diOH18:1-OH18:1-diOH18:1, OH18:1-diOH18:1-diOH18:1 and diOH18:1-diOH18:1-OH18:1 combined. The approximate contents of other regioisomers were as follows: diOH18:1-OH18:1-OH18:1 (92%), diOH18:1-diOH18:0-diOH18:1 (91%), diOH18:2-OH18:1-OH18:1 (80%) and diOH18:0-OH18:1-OH18:1 (96%). The ratios of regioisomers of TAG (ABC) containing three different fatty acids were estimated as about 7:1:2 (OH18:1:diOH18:1:diOH18:2) and about 7:2:1 (OH18:1:diOH18:0:diOH18:1). Ricinoleate (OH18:1) was predominately at the sn-2 position of TAG (both AAB and ABC) containing dihydroxy fatty acids and ricinoleate. Dihydroxy fatty acids were mainly at the sn-1,3 positions of TAG containing dihydroxy fatty acids and ricinoleate in castor oil. The ratios of the three regioisomers of TAG (ABC) containing three different fatty acids by mass spectrometry are first reported here.     

Acylglycerols Containing Trihydroxy Fatty Acids in Castor Oil and the Regiospecific Quantification of Triacylglycerols

Ricinoleate, a monohydroxy fatty acid in castor oil, has many industrial uses. Dihydroxy and trihydroxy fatty acids can also be used in industry. We report here the identification of diacylglycerols (DAG) and triacylglycerols (TAG) containing trihydroxy fatty acids in castor oil. The C₁₈ HPLC fractions of castor oil were used for mass spectrometry of the lithium adducts of acylglycerols to identify trihydroxy fatty acids and the acylglycerols containing trihydroxy fatty acids. Two DAG identified were triOH18:1–diOH18:1 and triOH18:0–OH18:1. Four TAG identified were triOH18:1–OH18:1–OH18:1, triOH18:0–OH18:1–OH18:1, triOH18:1–OH18:1–diOH18:1 and triOH18:0–OH18:1–diOH18:1. The structures of these two newly identified trihydroxy fatty acids were proposed as 11,12,13-trihydroxy-9-octadecenoic acid and 11,12,13-trihydroxyoctadecanoic acid. The locations of these trihydroxy fatty acids on the glycerol backbone were almost 100% at the sn-1,3 positions or at trace levels at the sn-2 position. The content of these acylglycerols containing trihydroxy fatty acids was at the level of about 1% or less in castor oil.     

Identification of TAG and DAG and their FA Constituents in Lesquerella (Physaria fendleri) Oil by HPLC and MS

Castor oil has many industrial uses because of its high content (90 %) of the hydroxy fatty acid, ricinoleic acid (OH¹²18:1⁹). Lesquerella oil containing lesquerolic acid (Ls, OH¹⁴20:1¹¹) is potentially useful in industry. Ten molecular species of diacylglycerols and 74 molecular species of triacylglycerols in lesquerella (Physaria fendleri) oil were identified by electrospray ionization mass spectrometry as lithium adducts of acylglycerols in the HPLC fractions of lesquerella oil. Among them were: LsLsO, LsLsLn, LsLsL, LsLn–OH20:2, LsO–OH20:2 and LsL–OH20:2. The structures of the four new hydroxy fatty acid constituents of acylglycerols were proposed by the MS of the lithium adducts of fatty acids as (comparing to those in castor oil): OH¹²18:2^9,14 (OH¹²18:2^9,13 in castor oil), OH¹²18:3^9,14,16 (OH18:3 not detected in castor oil), diOH^12,1318:2^9,14 (diOH^11,1218:2^9,13 in castor oil) and diOH^13,1420:1¹¹ (diOH20:1 not detected in castor oil, diOH^11,1218:1⁹ in castor oil). Trihydroxy fatty acids were not detected in lesquerella oil. The differences in the structures of these C18 hydroxy fatty acids between lesquerella and castor oils indicated that the polyhydroxy fatty acids were biosynthesized and were not the result of autoxidation products.     

Identification of Minor Acylglycerols Less Polar than Triricinolein in Castor Oil by Mass Spectrometry

Acylglycerols in castor oil less polar than triricinolein were identified by electrospray ionization–mass spectrometry using the lithium adducts of the acylglycerols in the HPLC fractions of castor oil. Thirty four new molecular species of acylglycerols containing hydroxy fatty acids in castor oil were identified by MS. The chain lengths of fatty acid substituents were C16, C18, C20, C22 and C23. The numbers of double bonds of the fatty acids were from zero to three. The numbers of hydroxyl groups on the fatty acid chains were from zero to three as previously reported. The structure of fatty acid, OH18:2, was proposed as 12-hydroxy-9,13-octadecadienoic acid. An unusual odd-numbered long-chain fatty acid, 23:0 (tricosanoic acid), was identified. Some new estolides and tetraacylglycerols, were identified as (12-ricinoleoylricinoleoyl)-ricinoleoyl-linoleoyl-glycerol (RRRL), (12-ricinoleoylricinoleoyl)-ricinoleoyl-oleoyl-glycerol (RRRO), (12-ricinoleoylricinoleoyl)-ricinoleoyl-palmitoyl-glycerol (RRRP), (12-ricinoleoylricinoleoyl)-ricinoleoyl-stearoyl-glycerol (RRRS) and (12-ricinoleoylricinoleoyl)-ricinoleoyl-linolenoyl-glycerol (RRRLn). The normal fatty acid (non-hydroxylated) of these tetraacylglycerols were directly attached to the glycerol backbone. The biosynthetic pathway of castor oil is proposed.     

Mass Spectrometry of the Lithium Adducts of Diacylglycerols Containing Hydroxy FA in Castor Oil and Two Normal FA

Castor oil can be used in industry. The molecular species of triacylglycerols containing hydroxy fatty acids (FA) in castor oil have been identified. We report here the identification of twelve diacylglycerols (DAG) containing hydroxy FA in castor oil using positive ion electrospray ionization mass spectrometry of the lithium adducts. They were RR (diricinolein, R is ricinoleate), RL, RS, R‐diOH18:0, R‐diOH18:1, R‐diOH18:2, R‐triOH18:0, R‐triOH18:1, R‐triOH18:2, diOH18:0‐diOH18:1, diOH18:1‐diOH18:1 and diOH18:1‐diOH18:2. The MS² fragment ions, [M + Li ? FA]⁺ and [FA + Li]⁺, from the lithium adducts of DAG containing hydroxy FA (one or two hydroxy FA), were used for the identification. The additional fragment ions from the neutral losses of FA lithium salts [M + Li ? FALi]⁺ were used for the identification of eleven DAG containing two normal FA in a soybean oil bioconversion product. The MS² fragment ions from the neutral losses of FA lithium salts [M + Li ? FALi]⁺ were not detected from the DAG containing hydroxy FA. The DAG containing FA with more hydroxyl groups than the other FA on the same DAG molecule tended to have a prominent fragment ion [FA + Li]⁺ and an undetectable fragment ion [M + Li ? FA]⁺ while the FA was the more hydroxylated FA. Also the less hydroxylated FA of a DAG tended to have a prominent fragment ion [M + Li ? FA]⁺ and an undetectable fragment ion [FA + Li]⁺ while the FA was the less hydroxylated FA.     

Ratios of Regioisomers of the Molecular Species of Triacylglycerols in Lesquerella (Physaria fendleri) Oil Estimated by Mass Spectrometry

The ratios of regioisomers of 72 molecular species of triacylglycerols (TAG) in lesquerella oil were estimated using the electrospray ionization mass spectrometry of the lithium adducts of TAG in the HPLC fractions of lesquerella oil. The ratios of ion signal intensities (or relative abundances) of the fragment ions from the neutral losses of fatty acids (FA) as α‐lactones at the sn‐2 position (MS³) of the molecular species of TAG were used as the ratios of the regioisomers. The order of the preference of FA incorporation at the sn‐2 position of the molecular species of TAG in lesquerella was as: normal FA > OH18 (monohydroxy FA with 18 carbon atoms) > diOH18 > OH20 > diOH20, while in castor was as: normal FA > OH18 > OH20 > diOH18 > triOH18. Elongation (from C₁₈ to C₂₀) was more effective than hydroxylation in lesquerella to incorporate hydroxy FA at the sn‐1/3 positions. The block of elongation in lesquerella may be used to increase the content of hydroxy FA, e.g., ricinoleate, at the sn‐2 position of TAG and to produce triricinolein (or castor oil) for industrial uses. The content of normal FA at the sn‐2 position was about 95 %, mainly oleate (38 %), linolenate (31 %) and linoleate (23 %). This high normal FA content (95 %) at the sn‐2 position was a big space for the replacement of ricinoleate to increase the hydroxy FA content in lesquerella oil. The content of hydroxy FA at the sn‐1/3 positions was 91 % mainly lesquerolic acid (85 %) and the content of normal FA was 6.7 % at the sn‐1/3 position in lesquerella oil.     

Analysis of hydroxylated fatty acids from plant oils

A novel process has been described recently for the preparation of hydroxylated fatty acids (HOFA) and HOFA methyl esters from plant oils. HOFA methyl esters prepared from conventional and alternative plant oils were characterized by various chromatographic methods (thin-layer chromatography, high-performance liquid chromatography, and gas chromatography) and gas chromatography-mass spectrometry as well as¹H and¹³C nuclear magnetic resonance spectroscopy. HOFA methyl esters obtained fromEuphorbia lathyris seed oil, low-erucic acid rapeseed oil, and sunflower oil contain as major constituents methylthreo-9,10-dihydroxy octadecanoate (derived from oleic acid) and methyl dihydroxy tetrahydrofuran octadecanoates, e.g., methyl 9,12-dihydroxy-10,13-epoxy octadecanoates and methyl 10,13-dihydroxy-9,12-epoxy octadecanoates (derived from linoleic acid). Other constituents detected in the products include methyl esters of saturated fatty acids (not epoxidized/derivatized) and traces of methyl esters of epoxy fatty acids (not hydrolyzed). The products that contain high levels of monomeric HOFA may find wide application in a variety of technical products.     

Base/acid-catalyzed FAEE production from hydroxylated vegetable oils

In this study was developed a new methodology to produce fatty acid ethyl esters from castor oil. The base-catalyzed transesterification step was followed by on pot addition of sulfuric acid. That addition implicated the successful separation of FAEEs/glycerin phases due to soap breaking. The study was carried out through an experimental design where the variables studied in the first step were the molar ratio alcohol:oil and the catalyst amount in the transesterification process. As expected, the on pot addition of concentrated sulfuric acid yields FFAs that increase the acid value in the FAEEs phase. A second step esterification of these free fatty acids from FAEE raw mixture was investigated. The esterification of FFA was carried out in 60:1 and 80:1 M ratios (alcohol:free fatty acids) and concentrated sulfuric acid 5% and 10% w/w (based on free fatty acids). Consequently, these two steps yielded more fatty ethyl esters and assure that the following important requirements in the FAEEs production process from castor oil are satisfied: complete reaction, best separation of FAEEs/glycerin phases, removal of catalyst, limpid glycerin, and absence of free fatty acids.     

Peanut oil: Compositional data

The major fatty acids of peanut oil acylglycerols are palmitic (C16:0), oleic (C18:1), and linoleic (C18:2) acids, and only a trace amount of linolenic fatty acid (C18:3) is present. Thus they have a very convenient oxidative stability and have been considered premium cooking and frying oils. This paper provides information about compositional data of peanut oil taking into account major (triacylglycerols and their fatty acids) and minor (free fatty acids, diacylglycerols, phospholipids, sterols, tocopherols, tocotrienols, triterpenic and aliphatic alcohols, waxes, pigments, phenolic compounds, volatiles, and metals) compounds. Moreover, the influence of genotype, seed maturity, climatic conditions, and growth location on peanut oil chemical composition is considered in the present report. In addition, peanut oils from wild species found in South America as well as from peanut lines developed through conventional breeding are also compared.     

Analysis of estolides in technical hydroxylated fatty acids from plant oils

Gel permeation chromatography of hydroxylated fatty acids (HOFA), prepared from various plant oils by a novel technical process, showed the presence of considerable amounts of estolides formed by intermolecular esterification of the HOFA. Thin-layer chromatographic fractionation followed by gas chromatography of the fractions revealed that the nonpolar estolides contain predominantly saturated fatty acids esterified tothero-9, 10-dihydroxy octadecanoic acid or dihydroxy tetrahydrofuran octadecanoic acids, e.g., 9,12-dihydroxy-10, 13-epoxy octadecanoic acid and 10,13-dihydroxy-9, 12-epoxy octadecanoic acid. The fractions of polar estolides consist mainly of intermolecular esters of the above dihydroxy fatty acids.     

General properties and the fatty acid composition of the oil from the mophane caterpillar, Imbrasia belina

A preliminary investigation of the bulk properties of the oil from the edible mophane caterpillar (phane), Imbrasia belina, showed a significant difference in the iodine values of the oils from mature and young phane. Detailed analysis of the fatty acid composition of the two oil samples was thus carried out by capillary gas chromatography (GC) and complemented with ¹H and ¹³C nuclear magnetic resonance (NMR) studies to investigate the degree of unstauration in the two oil samples. While these studies showed that the oil samples from the mature and young mophane caterpillar were much the same in fatty acid composition, the data revealed a significant divergence from a literature report on phane oil. This earlier report puts the ratio of total saturated to total unsaturated fatty acids at approximately 1:1 (48.2:48.8, in percentages) and estimates the fatty acid composition for the major fatty acids as 16:0 (31.9%), 18:0 (15.2%), 18:1 (20.4%), 18:2 (9.9%), and 18:3 (19%). The data collected from the present work, however, showed the fatty acid composition for total saturated and total unsaturated fatty acids to be 40.5 and 57.0%, respectively. This work estimated the fatty acid composition for the major fatty acids as 16:0 (27.2%), 18:0 (12.3%), 18:1 (16.1%), 18.2 (10.7%), and 18:3 (29.0%). Thus, linolenic acid was the most abundant fatty acid in the phane oil. The GC results of the present analysis were largely corroborated by studies of the composition of fatty acid classes in the phane oil estimated from integrals of ¹H and ¹³C NMR signals. Oils from other edible Lepidoptera larvae are also known to be much richer in unsaturated than saturated fatty acids.     

Fatty Acids in Vernonia Produced in the Mid-Atlantic Region of the United States

Vernonia galamensis [(Cass.) Less.] is a native of Ethiopia and Eritrea. Seed of vernonia contain substantial quantities of naturally epoxidized oil, which is used in the paint industry to reduce emissions of volatile organic compounds that produce smog resulting from the use of petroleum-based (alkyd-resin) paint. Epoxidized oil is also used in the manufacture of plasticizers, additives to polyvinyl chloride, polymer blends and coatings, and cosmetic and pharmaceutical applications. Previous research has indicated that vernonia has potential for commercialization in the mid-Atlantic region of the United States. This study characterized fatty acids in oil from vernonia grown in this latter region. Vernonia oil, from 14 vernonia lines grown during 1995 and 1996 under field conditions in Virginia, contained 3.3, 3.0, 5.0, 15.0, 0.2, 0.5, 0.4, and 72.7%, respectively, of C16:0, C18:0, C18:1, C18:2, C18:3, C20:0, C20:1, and vernolic (C18:1 epoxy) fatty acids. Effects of genotypes on vernonia oil quality were generally not significant whereas the effects of years were significant. The concentration of vernolic acid was positively correlated with oil concentration but negatively correlated with concentrations of all individual fatty acids, except for C18:3. Contribution of Virginia State University Agricultural Research Station, journal article series number 253. The use of any trade names or vendors does not imply approval to the exclusion of other products or vendors that may also be suitable.     

A novel technique for the preparation of secondary fatty amides II: The preparation of ricinoleamide from castor oil

The butyl amide of ricinoleic acid (N-n-butyl-12-hydroxy-(9Z)-octadecenamide) was prepared from a neat mixture of castor oil andn-butylamine (fatty ester/amine molar ratio, 1:1.3). No catalyst was required. The identity and purity of the amide was assessed by thin-layer chromatography and confirmed by elemental analysis and by infrared and C¹³ nuclear magnetic resonance spectroscopy. High product yields were achieved at 45 and 65°C in 48 and 20 h, respectively. The reaction was inhibited by the addition of trimethylpentane and dioxane, but not by water. An attempt was made to prepare the amide from methyl ricinoleate, rather than castor oil; even after 10 d only partial conversion was achieved. Attempts to prepare the amide from methyl-n-butylamine, rather thann-butylamine, were also unsuccessful. The ease with which secondary fatty amides can be produced from an oil that consists primarily of the glycerol esters of hydroxylated fatty acids indicates that the described procedure has industrial utility.     

Synthesis and characterization of hyperbranched and air drying fatty acid based resins

In this research four hyperbranched resins having fatty acid residues were synthesized. Dipentaerythritol, which was used as the core molecule of the resins, was twice esterified with dimethylol propionic acid. This resin was then esterified with the castor oil fatty acids. The hydroxyl group present in the ricinoleic acid which constitutes almost 87% of the castor oil fatty acids was then reacted with linseed oil fatty acids and benzoic acid. The linseed fatty acids were incorporated into the structure to esterify 0, 15, and 70% of the ricinoleic acid on mole basis. These resins were named as HBR-1, 2, and 3. A fourth resin (e.g. HBR-4) was synthesized by the incorporation of ‘15% linseed fatty acids + 55% benzoic acid’. The chemical characterization of the resins was achieved by FTIR spectroscopy and the thermal properties were determined by DSC. The physical and the mechanical properties of the resins were determined. The hardness value of the resins was measured as 24, 27, 25, and 68 Persoz for HBR-1, 2, 3, and 4, respectively. The viscosity of the resins was measured as 17.3, 9.7, 5.8, and 17.5 Pa·s at a shear rate of 200 s⁻¹. The increase in the amount of the linseed fatty acids increased the hardness, and decreased the viscosity of the resins. All resins showed excellent adhesion, gloss, and flexibility.     

Comparison of the Structures of Triacylglycerols from Native and Transgenic Medium-Chain Fatty Acid-Enriched Rape Seed Oil by Liquid Chromatography–Atmospheric Pressure Chemical Ionization Ion-Trap Mass Spectrometry (LC–APCI-ITMS)

The sn position of fatty acids in seed oil lipids affects physiological function in pharmaceutical and dietary applications. In this study the composition of acyl-chain substituents in the sn positions of glycerol backbones in triacylglycerols (TAG) have been compared. TAG from native and transgenic medium-chain fatty acid-enriched rape seed oil were analyzed by reversed-phase high performance liquid chromatography coupled with online atmospheric-pressure chemical ionization ion-trap mass spectrometry. The transformation of summer rape with thioesterase and 3-ketoacyl-[ACP]-synthase genes of Cuphea lanceolata led to increased expression of 1.5% (w/w) caprylic acid (8:0), 6.7% (w/w) capric acid (10:0), 0.9% (w/w) lauric acid (12:0), and 0.2% (w/w) myristic acid (14:0). In contrast, linoleic (18:2n6) and alpha-linolenic acid (18:3n3) levels decreased compared with the original seed oil. The TAG sn position distribution of fatty acids was also modified. The original oil included eleven unique TAG species whereas the transgenic oil contained sixty. Twenty species were common to both oils. The transgenic oil included trioctadecenoyl-glycerol (18:1/18:1/18:1) and trioctadecatrienoyl-glycerol (18:3/18:3/18:3) whereas the native oil included only the latter. The transgenic TAG were dominated by combinations of caprylic, capric, lauric, myrisitic, palmitic (16:0), stearic (18:0), oleic (18:1n9), linoleic, arachidic (20:0), behenic (22:0), and lignoceric acids (24:0), which accounted for 52% of the total fat. In the original TAG palmitic, stearic, oleic, and linoleic acids accounted for 50% of the total fat. Medium-chain triacylglycerols with capric and lauric acids combined with stearic, oleic, linoleic, alpha-linolenic, arachidic, and gondoic acids (20:1n9) accounted for 25% of the transgenic oil. The medium-chain fatty acids were mainly integrated into the sn-1/3 position combined with the essential linoleic and alpha-linolenic acids at the sn-2 position. Eight species contained caprylic, capric, and lauric acids in the sn-2 position. The appearance of new TAG in the transgenic oil illustrates the extensive effect of genetic modification on fat metabolism by transformed plants and offers interesting possibilities for improved enteral applications.     

Identification of Tetraacylglycerols in Lesquerella Oil by Electrospray Ionization Mass Spectrometry of the Lithium Adducts

Tetraacylglycerol (an acylglycerol estolide) contains an acyl chain attached to the hydroxyl group of another acyl chain attached to the glycerol backbone. Lesquerolic acid (Ls, OH¹⁴20:1¹¹) is the main fatty acid in lesquerella oil and may be used industrially for the manufacture of biodegradable industrial products. Electrospray ionization mass spectrometry of the lithium adducts of acylglycerols in the high-performance liquid chromatography fractions from the seed oil of lesquerella (Physaria fendleri) was used to identify thirteen tetraacylglycerols. They were LsLsLsLn, LsLsLsL, LsLs-OH20:2-O, LsLsLsO, LsLsLnLn, LsLsLLn, LsLsOLn, LsLsLL, LsLsOL, LsLsOP, LsLsOO, LsLsLS and LsLsOS. The OH20:2 was auricolic acid (OH¹⁴20:2^11,17). For the four tetraacylglycerols containing one normal fatty acid (non-hydroxy fatty acid), LsLsLsLn, LsLsLsL, LsLs-OH20:2-O and LsLsLsO, the normal fatty acids were all directly attached to the glycerol backbone, not to the hydroxyl group of fatty acids. We propose that the biosynthetic precursors (triacylglycerol acyltransferase) of these four tetraacylglycerols were LsLsLn, LsLsL, LsLsO (Ls-OH20:2-O) and LsLsO individually. LsLsO and Ls-OH20:2-O were equally active as the biosynthetic precursors for LsLs-OH20:2-O. For LsLsLS, linoleate were all attached to the glycerol backbone and LsLsL was proposed to be the biosynthetic precursor. For LsLsOS, stearate were all attached to the glycerol backbone and LsLsS was proposed to be the biosynthetic precursor. For the other seven tetraacylglycerols containing two normal fatty acids, LsLsAB, the biosynthetic precursors could be both LsLsA and LsLsB.     

Novel bisphosphonates via castor oil

Hydroxy fatty acids (HFAs) have long been a staple component of feedstock oils with uses ranging from motor oils to food to pharmaceuticals. Castor oil, which contains the HFA ricinoleic acid as its principal component, is the most widely used source of HFA in the world. In addition, bisphosphonates are a functional moiety that has been shown to display a variety of industrial applications, ranging from use in water softeners to osteoporosis drugs, primarily due to their affinity for the calcium ion. We have long been interested in the modification of ricinoleic acid from castor oil to phosphorus derivatives, including α-hydroxy phosphonates and phosphonic acids, and have now accomplished the synthesis of a family of ricinoleic-derived bisphosphonates: one that retains the cis alkene found in ricinoleic acid and one where the alkene has undergone hydrogenation. These compounds have been produced in high yields and high purity and the synthesis of these compounds is reported.     

Enzymatic incorporation of docosahexaenoic acid into borage oil

Lipase-catalyzed acidolysis of acylglycerols of borage (Borago officinalis L.) oil with a docosahexaenoic acid (DHA) concentrate, prepared from algal oil, in organic solvents was studied. Seven lipases were used as biocatalysts for the acidolysis reaction. Novozyme 435 from Candida antarctica, as compared to lipases from Mucor miehei and Pseudomonas sp., showed the highest degree of DHA incorporation into borage oil. Other lipases tested, such as those from Aspergillus niger, C. rugosa, Thermomyces lanuginousus and Achromobacter lunatus, were rather ineffective in the incorporation of DHA into borage oil. Effects of variation of reaction parameters, namely, enzyme load, temperature, time course, and type of solvent, were monitored for C. antarctica as the biocatalyst of choice. Incorporation of DHA increased with increasing amount of enzyme, reaching 27.4% at an enzyme concentration of 150 lipase activity units. As incubation time progressed, DHA incorporation also increased. After a reaction time of 24 h, the contents of total n-6 and n-3 polyunsaturated fatty acids in acylglycerols were 44.0 and 27.6%, respectively. The highest degree of DHA incorporation was achieved when hexane was used as the reaction medium. The positional distribution of DHA in modified borage oil was determined using pancreatic lipase hydrolysis. Results showed that DHA was randomly distributed over the sn-1, sn-2, and sn-3 positions of the triacylglycerol. Thus, preparation of modified borage oil acylglycerols containing both DHA (22:6n-3; 27.4%) and γ-linolenic acid (18:3n-6; 17.0%) was successfully achieved and products so obtained may have beneficial effects beyond simple physical mixtures of the two oils. The final oil had a ratio of n-3 to n-6 of 0.42–0.62 which is nutritionally more suitable than the original unaltered borage oil.     

DC-Trennung von Ricinusölfettsäure-Estoliden

TLC Separation of Estolides of Castor Oil Fatty Acids Estolides of castor oil fatty acids (polyricinoleic acids) with varying degrees of condensation were synthesized by heating the castor oil fatty acids at 120° C–240° C under vacuum and CO₂ circulation. These products were analyzed by chemical constants and fractionated by TLC on silicagel 60 precoated plates into ricinoleic acid and di-, tri- as well as tetra-ricinoleic acids. Furthermore, the estolides were separated by two-dimensional TLC into two series of estolides, i.e. estolides containing only ricinoleic acid and those which contain fatty acids other than ricinoleic acid at the chain terminal. Hydrogenated castor oil fatty acids (technical 12-hydroxystearic acid) also form estolides which can be fractionated in a similar manner. Thus, TLC provides information on the oligomeric and polymeric character of the estolides of castor oil fatty acids and permits separation even of the decamers.     

Vegetable oil raw materials

Vegetable oils that are important to the chemical industry include both edible and industrial oils, which contribute 24% and 13.5%, respectively, compared to 55% for tallow, to the preparation of surfactants, coatings, plasticizers, and other products based on fats and oils. Not only the oils themselves but also the fatty acids recovered from soapstock represent a several billion pound resource. Coconut oil is imported to the extent of 700-1,000 million pounds per year. Its uses are divided about equally between edible and industrial applications. Safflower oil has a relatively small production, but 15–25% of the oil goes into industrial products. Soybean oil, the major edible oil of the world, is produced in the United States at the rate of 11,000 million pounds per year with more than 500 million pounds going into industrial uses, representing 5% of the total production. Castor oil is imported to the extent of about 100 million pounds per year. Linseed oil production has declined drastically over the last 25 years but still amounts to about 100 million pounds per year. Oiticica and tung oils are imported in lesser amounts than castor and linseed oils. New crops that have industrial potential, as well as the traditional vegetable oil crops, include seed oils from crambe,Limnanthes, Lesquerella, Dimorphotheca, Vernonia, andCuphea plants. Crambe oil contains up to 65% erucic acid. Oil fromLimnanthes contains more than 95% of fatty acids above C₁₈.Lesquerella oil contains hydroxy unsaturated acids resembling ricinoleic acid from castor oil.Dimorphotheca oil contains a conjugated dienol system.Vernonia oils contain as much as 80% epoxy acids. TheCuphea oils contain a number of short chain fatty acids. Of these, crambe,Limnanthes, andVernonia are probably the most developed agronomically. Competition between vegetable oils and petrochemicals for the traditional fats and oil markets has been marked over the past 25 years, but prices for petrochemicals have accelerated at a greater rate than those for vegetable oils; and, it is now appropriate to reexamine the old as well as the new markets for fatty acids.