Enzymatic synthesis and spectroscopic characterization of 1,3-divernoloyl glycerol fromVernonia galamensis seed oil

cis-12,13-Epoxy-cis-octadecenoic (vernolic) acid occurs in triglycerides of the seed oil ofVernonia galamensis. The seeds also contain a lipase capable of hydrolyzing the triglycerides. Previous investigators incubated the seed ofVernonia anthelmintica and isolated 5.6% yield of 1,3-divernoloyl glycerol. We used crude lipase extract fromV. galamensis seed to synthesize 1,3-divernoloyl glycerol from vernonia oil in pentane at 40% yield. A 94% conversion of the 1,3-divernoloyl glycerol to pure vernolic acid (5.34% oxirane = 98.9% purity) was achieved by a low-energy saponification process. The carbon-13 nuclear magnetic resonance (NMR) spectrum of the 1,3-divernoloyl glyceride indicates a potential for using carbon-13 NMR spectroscopy in the identification of isomeric diglycerides. Thus the paper describes the synthesis, spectroscopic and chemical characterization of 1,3-divernoloyl glycerol, in addition to providing quantitative carbon-13 NMR studies ofV. galamensis oil.     

Vernonia galamensis: A rich source of epoxy acid

A percolation extraction ofVernonia galamensis seed, affording 38.6% of crude vernonia oil is described. The dark colored crude oil was degummed with water, treated with activated charcoal and bleached with a neutral agent, to give a light colored oil (Lovibond: 0.9 red, 3.5 yellow). Gas chromatographic/mass spectrometric analysis of the refined oil indicates a relative fatty acid composition of 79–81% vernolic (cis-12,13-epoxy-cis-9-octadecenoic) acid, 11–12% linoleic acid, 4–6% oleic acid, 2–3% stearic acid, 2–4% palmitic acid, and a trace amount of arachidic acid.     

Mass spectrometric characterization ofVernonia galamensis oil

Vernonia galamensis seed oil is a natural source of epoxidized triacylglycerols, which consist of 52% trivernolin and a mixture of other triacylglycerols. Epoxidized oils are used for industrial applications, such as coatings and plastic formulations. To determine the major molecular species present in Vernonia oil, desorption chemical ionization/mass spectrometry and mass spectrometry/mass spectrometry were used to determine its glyceride composition. Seven triacylglycerols predominated: divernoloylarachidonate, trivernolin, divernoloylstearate, divernoloyloleate, divernoloyllinoleate, dilinolenoyl vernolate and divernoloylpalmitate.     

Biodegradation ofVernonia galamensis seed Oil byAcinetobacter andPseudomonas sp.

The biodegradability ofVernonia galamensis seed oil (VO) has been demonstrated with two environmental bacterial strains,Acinetobacter Iwoffi (HU 3955), andPseudomonas sp. (HU 4020). A time-dependent increase in the degradative activities of both bacteria species was apparent. There wasca. 60% decrease in the amount of VO over an eightday incubation period. Additionally, lipolytic activity was evident from the amount of free fatty acid (FFA) that was generated. The percent FFA of the residual oil were 82% for thePseudomonas strain, and 62% for theAcinetobacter strain. The weight per epoxy value of the VO in the fermentation medium remained relatively constant over the incubation period, suggesting the lack of preference for either the epoxidized or nonepoxidized acids present in VO.     

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of Vernonia galamensis oil

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) has been used to identify eight triacylglycerols (TAG) in Vernonia galamensis oil (VO). The TAG include trivernolin, divernoloylstearoylglycerol, divernoloyloleoylglycerol, vernoloyllinoleoylstearoylglycerol, vernoloyllinoleoyloleoylglycerol, and vernoloyldilinoleoylglycerol. Samples for the MALDI/TOF/MS analysis were prepared with alpha-cyano-4-hydroxycinnamic acid (matrix) in an acetonitrile/tetrahydrofuran solvent system. A mol ratio of matrix/VO (44:1) gave reproducible composite spectra, resulting in resolutions greater than 8,000 and signal-to-noise ratios of above 1000 for the most abundant molecular species. 1,3-Dioleoyl-2-stearoylglycerol and 1,2-dioleoyl-3-palmitoylglycerol were used as calibration standards.     

Synthesis and isolation of epoxy secondary amidesvia direct amidation ofVernonia galamensis seed oil

Vernonia galamensis oil, containing naturally epoxidized triglycerides, was reacted withn-butylamine,n-pentylamine andn-hexylamine to afford high yields of epoxidized secondary amides. Three reaction conditions were investigated: (i) reflux with amines as solvents, (ii) reflux with hexane as the solvent and (iii) room temperature with the amines as solvents. Reactions with amines as refluxing solvents were completed in 1–5 h, while those with hexane went to completion within 2 to 5 d. Room temperature reactions were onlyca. 80% complete after several days. Reactivity was increased with higher amine homologs at both reflux and room temperature reaction conditions. Isolated yields of epoxy-containing amides were about 80% with purity exceeding 96% in all cases. Spectroscopic characterization of the previously unreported alkyl-vernolamides is provided.     

Acid-catalyzed alcoholysis ofVernonia galamensis oil

We have demonstrated the potential ofVernonia galamensis seed oil as a source of hydroxy alkoxy fatty esters. Reaction of the oil with various alcohols (methanol, ethanol, 1-propanol and 2-propanol), under acidic conditions, resulted in transesterification as well as epoxy ring opening in all cases. The major products, the hydroxy alkoxy fatty esters, constituted approximately 80% of the product mixtures, of which the 12-hydroxy-13-alkoxy isomers were the major constituents. These derivatives were isolated by solvent extraction and/or column chromatography to afford 78–80% of pure isomers. Alcoholysis with butanol resulted in a poor yield of the hydroxy butoxy esters. A discussion of the isolation and mass-spectrometric characterization of these new esters is provided.     

超声强化提取薏苡仁油的研究

研究了提取溶剂、提取温度、料液比、薏苡仁粒径、提取时间对超声提取薏苡仁油的影响。在单因素实验的基础上 ,进行了正交实验。结果表明 ,各因素对油提取率的影响次序为 :物料粒径 >超声提取温度 >超声提取时间 >超声频率和功率 >料液比。优化后的工艺参数为 :提取温度 50℃ ,物料粒径 60～ 80目 ,料液比 1∶3 5 ,超声功率和频率 2 5kHz、30 0W ,提取时间40min。     

Extraction and characterization ofDimorphotheca pluvialis seed oil

Dimorphotheca pluvialis is increasingly recognized as an interesting industrial new oilseed crop because it contains up to 60% of the unusual fatty acid dimorphecolic acid (9-hydroxy,10t,12t-18∶2) (DA) for which new applications are being developed. In this paper, the yield, composition and quality are evaluated for dimorphotheca oils (DMO) which were recovered by pressing, conventional solvent extraction and supercritical carbon dioxide extraction (SCE). Mechanical pressing of the seeds required high temperatures and resulted in an oil recovery of only 40%, whereas the extraction protocols yielded more than 95%. Oil recovery by pressing of winged seed was even more difficult than that of unwinged seeds; hence, solvent extraction of winged seeds was preferred. The dark-colored DMO, recovered by expelling or by extraction with organic solvents, needed further refining to remove pigments and gums, whereas the light yellow-colored SCE DMO did not require further refining. SCE oil had a low phospholipid content (11 mg P/kg). Pressed oil (95 mg P/kg) and hexaneor pentane-extracted DMO (200 mgP/kg) had much higher phospholipid contents. Peroxide andp-anisidine values were low for freshly recovered oils, but increased after storage, especially in the SCE oil, due to the low concentration of natural antioxidants in SCE DMO, such as tocopherols. The DA content of the oils recovered by the various techniques showed only minor differences, except that supercritical carbon dioxide had slightly decreased solubilizing power for tri- and di-dimorphecolin as compared to hexane and pentane.     

Investigation of the technological properties ofNigella sativa (black cumin) seed oil

Three commercially cultivatedNigella sativa seed varieties of Turkish origin were analyzed, and the characteristics and constituents of the seed oils were reported. Presence of lipase enzyme in seed results in enzymatic hydrolysis at ordinary temperature; the free acid content of oil may increase up to 40% or higher. Black cumin seed oil might serve as a source of semi-drying oil and fatty acids of technical grade, and the removal of free fatty acids from oil and the recovery of fatty acids were investigated.     

Solvent extraction of oil from soybean flour II— pilot plant and two-solvent extractions

The process of grinding soybeans to a fine flour and extracting the flour with hexane was studied on a pilot plant scale. The crude oil from the pilot plant study had 15 ppm phosphorus and was suitable for physical refining after a light acid pretreatment and bleaching. The refined oil showed a Lovibond color of 1.4 yellow and 0.3 red. The pilot plant study also showed that grinding of the soybeans and the separation of solid from miscella were the most difficult steps in solvent extraction with fine flour. A laboratory study on separation of miscella from meal by aqueous ethanol reduced the hold-up volume, but it did not remove all the miscella. A test with betacarotene showed that only the miscella outside the flour particles was displaced. Aqueous ethanol solutions used as a second solvent extracted additional nontriglyceride materials (primarily phospholipids) from the meal. Also, the free fatty acid content of the oil was increased with aqueous ethanol solution wash. The quality of the extracted crude oil was lowered by using a second solvent, but it had the advantage of needing only one centrifugation to separate miscella from meal.     

Enzymatic pretreatment on rose-hip oil extraction: Hydrolysis and pressing conditions

In a previous report [Zúñiga, M.E., J. Concha, C. Soto, and R. Chamy, Effect of the Rose Hip (Rosa aff. rubiginosa) Oil Extraction Cold-Pressed Process, in Proceedings of the World Conference and Exhibition on Oilseed Processing, and Utilization, edited by R.F. Wilson, AOCS Press, Champaign, 2001, pp. 210–213], the authors showed that an enzymatic pretreatment of rose-hip seeds, prior to oil extraction by cold pressing, improves the oil yield. In this work, we studied the effects of temperature and moisture during the enzymatic hydrolysis stage using two previously selected mixtures of commercial enzymes: (i) Olivex (mainly pectinase) plus Cellubrix (mainly cellulase), and (ii) Finizym (mainly β-glucanase) plus Cellubrix (mainly cellulase) (all from Novozymes A/S, Madrid, Spain). In addition, we evaluated the effect of enzymatic hydrolysis on the oil extraction pressing rate at different operational pressures. Samples hydrolyzed enzymatically by either of the two commercial enzyme mixtures at 45°C and 30–40% moisture showed oil extraction yields up to 60%, an increase of greater than 50%, as compared with control samples in which the enzyme solutions were replaced by water. Both the oil extraction rate and yield by pressing increased when enzymatic pretreatment was applied. The oil extraction yield increased slightly when the operation pressure was elevated; however, when the sample was preheated, the oil extraction yield was greatly increased, especially for enzyme-treated samples. Results confirmed the importance of temperature and moisture as enzymatic hydrolysis parameters that improve rose-hip oil extraction yields in the cold-pressing process. When pressing was carried out after preheating enzymatically treated samples, it was possible to increase the oil extraction yield to 72% compared with the control without preheating, which resulted in a 46% oil yield.     

Deacidification of black cumin seed oil by selective supercritical carbon dioxide extraction

The deacidification of high-acidity oils from Black cumin seeds (Nigella sativa) was investigated with supercritical carbon dioxide at two temperatures (40 and 60°C), pressures (15 and 20 MPa) and polarities (pure CO₂ and CO₂/10% MeOH). For pure CO₂ at a relatively low pressure (15 MPa) and relatively high temperature (60°C), the deacidification of a highacidity (37.7 wt% free fatty acid) oil to a low-acidity (7.8 wt% free fatty acid) oil was achieved. The free fatty acids were quantitatively (90 wt%) extracted from the oil and left the majority (77 wt%) of the valuable neutral oils in the seed to be recovered at a later stage by using a higher extraction pressure. By reducing the extraction temperature to 40°C, increasing the extraction pressure to 20 MPa, or increasing the polarity of the supercritical fluid via the addition of a methanol modifier, the selectivity of the extraction was significantly reduced; the amount of neutral oil that co-extracted with the free fatty acids was increased from 23 to 94 wt%.     

Minor components ofLesquerella fendleri seed oil

Routine analysis of fatty ester fractions ofLesquerella fendleri oil suggested the presence of epoxy compounds and other minor components. By a combination of open silica column and high performance liquid chromatography (HPLC) fractionations of the methyl esters prepared from the oil, these constitutents were isolated and then characterized by thin-layer chromatography-mass spectrometry (GC-MS—electron ionization, EI, and chemical ionization, CI) and nuclear magnetic resonance (NMR—¹H and¹³C). Three epoxy acids, 15,16-epoxy-9,12-octadecadienoic, 9,10-epoxy-12-octadecenoic and 9,10-epoxy-octadecanoic, were found. Hydroxy acids present included a C-22 homologue of lesquerolic acid (16-hydroxy-12-docosenoic acid) and 14,15-dihydroxy-tricosanoic acid. Other minor ocmponents included four sterols, brassicasterol, campesterol, β-sitosterol and stigmasterol, and a series of saturated and unsaturated fatty acids up to C30. Visiting postdoctoral scientist sponsored by the government of India.     

Analyzing seed weight,fatty acid composition,oil, and protein contents in <Emphasis Type="Italic">Vernonia galamensis</Emphasis> germplasm by near-infrared reflectance spectroscopy

Vernonia galamensis is a potential new industrial oilseed crop from the Asteraceae family. The interest in this species is due to the presence of a high vernolic acid content of its seed oil, which is useful in the oleochemical industry for paints and coatings. The development of a rapid, precise, robust, nondestructive, and economical method to evaluate quality components is of major interest to growers, processors, and breeders. NIR reflectance spectroscopy (NIRS) is routinely used for the prediction of quality traits in many crops. This study was conducted to establish a rapid analytical method for determining the quality of intact seeds of V. galamensis. A total of 114 Vernonia accessions were scanned to determine seed weight, FA composition, oil, and protein contents using NIRS. Conventional chemical analysis for FA composition, total oil, and protein contents were performed by GC, Soxhlet extraction, and the Dumas combustion method, respectively. Calibration equations were developed and tested through cross-validation. The coefficient of determination in cross-validation for FA ranged from 0.47 (linoleic acid) to 0.55 (vernolic acid), and for oil, protein, and seed weight from 0.71 (oil) to 0.86 (seed protein). It was concluded that NIRS calibration equations developed for seed weight and seed quality traits can be satisfactorily used as early screening methods in V. galamensis breeding programs.     

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.     

Influence of lipase-catalyzed interesterification on the oxidative stability of melon seed oil triacylglycerols

Melon seeds are rich in oil. However, the stability of melon seed oil (MSO) is low because of its high content of the essential fatty acid, linoleic acid (18:2n-6). MSO was physically blended or enzymatically interesterified with higholeic sunflower oil (HOSO). The fatty acid composition of MSO was remarkably changed after interesterification. Palmitic (16:0), stearic (18:0), and oleic (18:1n-9) acid contents increased at the sn-2 position of triacylglycerols, whereas 18:2n-6 decreased due to interesterification. The oxidative stability of the physical and Pseudomonas sp. (PS30) lipase-interesterified blends was assessed with the Oxidative Stability Instrument, peroxide value, and conjugated diene methods. The stability of MSO increased with increased proportions of HOSO, which was the source of 18:1n-9 in the blends. The ratio of 18:1n-9/18:2n-6 improved from 0.18 in MSO to 1.47 in the enzymatically interesterified blend. Calculated oxidizability and the results of oxidation tests of the blends confirmed the improvement in MSO stability by both physical blending and enzymatic interesterification.     

Influence of lipase-catalyzed interesterification on the oxidative stability of melon seed oil triacylglycerols

Melon seeds are rich in oil. However, the stability of melon seed oil (MSO) is low because of its high content of the essential fatty acid, linoleic acid (18:2n-6). MSO was physically blended or enzymatically interesterified with higholeic sunflower oil (HOSO). The fatty acid composition of MSO was remarkably changed after interesterification. Palmitic (16:0), stearic (18:0), and oleic (18:1n-9) acid contents increased at the sn-2 position of triacylglycerols, whereas 18:2n-6 decreased due to interesterification. The oxidative stability of the physical and Pseudomonas sp. (PS30) lipase-interesterified blends was assessed with the Oxidative Stability Instrument, peroxide value, and conjugated diene methods. The stability of MSO increased with increased proportions of HOSO, which was the source of 18:1n-9 in the blends. The ratio of 18:1n-9/18:2n-6 improved from 0.18 in MSO to 1.47 in the enzymatically interesterified blend. Calculated oxidizability and the results of oxidation tests of the blends confirmed the improvement in MSO stability by both physical blending and enzymatic interesterification.     

超临界CO_2流体萃取植物油的实验研究

建立了一套超临界流体萃取实验装置,就大豆和花生两种植物油超临界流体萃取进行了较为详细的实验研究.在探讨了压力、温度、颗粒度、空隙率以及时间等对萃取率的影响之后,获得了指导实际生产的最佳工艺参数条件.     

Supercritical carbon dioxide extraction ofDimorphotheca pluvialis oil seeds

The possibility of extraction ofDimorphotheca oil with supercritical carbon dioxide is demonstrated in this article. Before extraction, the seeds have to be pretreated to improve extraction yield. Experiments showed that the best pretreatment procedure forDimorphotheca was heating the seeds under reduced pressure to 100°C for 60 min, followed by flaking or milling. To give an impression about the efficiency of the supercritical extraction, a mathematical model has been developed to estimate the overall mass transfer coefficient (A _p K). Also, an empirical relation betweenA _p K and the interstitial velocity has been found. The physical properties of the supercriticalDimorphotheca oil are in good agreement with those of conventionally extracted oil, except for a lower phospholipid content. It is expected that further refining of supercriticalDimorphotheca oil will be marginal.