Two-stage solvent extraction of seeds of <Emphasis Type="Italic">Hibiscus abelmoschus</Emphasis> linn: Lipid and FA compositions

The lipid and FA compositions of TAG seed oil of ambrette (Hibiscus abelmoschus), contrary to earlier reports, were found to contain only a small amount of epoxy FA. Higher HBr absorption values were shown to be due to the presence of fragrance components of the seed coat in the oil derived from intact whole seeds. Cyclopropene/cyclopropane acids in the FAME were determined to be about 1.5% by GLC, while epoxy acids were less than 1% by two different methods. Based on the physicochemical characteristics and lipid and FA compositions of the fresh and methanol-extracted seeds, ambrette TAG oil may be a candidate for edible use. The process of selective recovery of the expensive fragrant oily concentrate in higher yield in a first step and of an edible fatty oil in a second step makes it an attractive economic proposal.     

Hybrid <Emphasis Type="Italic">Hibiscus</Emphasis> seed oil compositions

The seeds of cultivated Hibiscus spp. were extracted with supercritical carbon dioxide, and the resulting extracts were analyzed to identify the major TG components as the corresponding FAME. The seed oils were composed predominantly of oleic and linoleic FA (69.6–83.4%) with lesser amounts of palmitic acid (14.8–27.0%). Minor amounts of C14, C18, and C20 saturated FA were also detected. The oil content of the seeds was determined to be between 11.8 and 22.1 wt% for hybrid varieties and between 8.9 and 29.5 wt% for the native species from which the hybrid varieties were developed. The protein content of the defatted seed meal averaged 20% for the hybrid varieties. The composition of the extracted hibiscus seed oils suggests potential edible applications.     

Characterization of laurel fruit oil from Madeira Island,Portugal

The fixed oil extracted from Laurus spp. fruit from Madeira Island, Portugal, is used in local traditional medicine for a wide variety of health complaints. Physical properties, density and refractive index, as well as the TAG FA composition, sterols, and waxes were determined. The oil was found to have an unusually high content of volatiles (ca. 10%), with trans-ocimene and germacrene D predominating. Oleic (30%) and linoleic (20%) acids were the main unsaturated FA, whereas lauric (18%) and palmitic (up to 22.5%) acids were the main saturated FA in the neutral lipid fraction. The oil had a sterol content on the same order as olive oil, with β-sitosterol (84%) predominating. Two sesquiterpene lactones, dehydrocostuslactone and costunolide, accounted for 5% of the overall composition. Madeira laurel oil is not currently used as an edible oil because of its very strong flavor. Its claimed medicinal properties have not yet been validated, and this is the first report on the characterization of the commercial product.     

Fatty Acid Composition and Oil Yield in Fruits of Five <Emphasis Type="Italic">Arecaceae</Emphasis> Species Grown in Cuba

The present study targeted the whole-fruit oil yield and fatty acid composition from five of the most abundant Arecaceae species grown in Cuba. The oil yields (% dry weight), determined by the Soxhlet extraction technique with hexane, were 25.5, 5.3, 6.9, 5.4, and 6.4% for Roystonea regia, Colpothrinax wrightii, Sabal maritima, Sabal palmetto and Thrinax radiata, respectively. The free fatty acid (FFA) content varied from 2.7 to 6.8%. Fatty acid (FA) profiles of the oils indicated that lauric acid (13.7–44.4%), myristic acid (9.4–22.4%) and palmitic acid (9.2–17.1%) as major saturated FA; whereas oleic acid (9.6–42.7%) and linoleic acid (9.3–17.0%) as major unsaturated FA. R. regia fruit seemed the most promising among Arecaceae grown in Cuba because of its high oil yield and low oil FFA content.     

A rapid method for the quantification of fatty acids in fats and oils with emphasis on <Emphasis Type="Italic">trans</Emphasis> fatty acids using fourier transform near infrared spectroscopy (FT-NIR)

A rapid method was developed for classifying and quantifying the FA composition of edible oils and fats using Fourier Transform near infrared spectroscopy (FT-NIR). The FT-NIR spectra showed unique fingerprints for saturated FA, cis and trans monounsaturated FA, and all n−6 and n−3 PUFA within TAG to permit qualitative and quantitative comparisons of fats and oils. The quantitative models were based on incorporating accurate GC data of the different fats and oils and FT-NIR spectral information into the calibration model using chemometric analysis. FT-NIR classification models were developed based on chemometric analyses of 55 fats, oils, and fat/oil mixtures that were used in the identification of similar materials. This database was used to prepare three calibration models—one suitable for the analysis of common fats and oils with low levels of trans FA, and the other two for fats and oils with intermediate and high levels of trans FA. The FT-NIR method showed great potential to provide the complete FA composition of unknown fats and oils in minutes. Compared with the official GC method, the FT-NIR method analyzed fats and oils directly in their neat form and required no derivatization of the fats to volatile FAME, followed by time-consuming GC separations and analyses. The FT-NIR method also compared well with the official FTIR method using an attenuated total reflectance (ATR) cell; the latter provided only quantification of specific functional groups, such as the total trans FA content, whereas FT-NIR provided the complete FA profile. The FT-NIR method has the potential to be used for rapid screening and/or monitoring of fat products, trans FA determinations for regulatory labeling purposes, and detection of contaminants. The quantitative FT-NIR results for various edible oils and fats and their mixtures are presented based on the FT-NIR model developed.     

Electrochemical hydrogenation of canola oil using a hydrogen transfer agent

A novel low-temperature process for the electrochemical hydrogenation of canola oil is described. An emulsion of oil and water containing formic acid and a nickel hydrogenation catalyst, placed in the cathode compartment of an electrolysis cell and subjected to an electrical current, underwent hydrogenation at temperatures as low as 45°C. At these low temperatures of hydrogenation, the trans FA content of the hydrogenated canola oil was very low as compared with that of the edible oils hydrogenated by commercial processes using high temperature and high partial pressure of hydrogen gas. Because of its adverse health effects, a high trans FA content in edbile oils is viewed as undesirable. In addition to the commercially available nickel supported on silica, amorphous nickelphosphorus alloys supported on a variety of substrates were also used. Amorphous alloys are generally very corrosion resistant because of the absence of grain boundaries. A mechanism for hydrogenation using the hydrogen transfer agent of formic acid and its continuous regeneration at the cathode was evoked to explain the experimental data.     

Production of linolenic acid in yeast cells expressing an omega-3 desaturase from tung (<Emphasis Type="Italic">Aleurites fordii</Emphasis>)

Tung oil is an industrial drying oil containing ca. 90% PUFA. We previously reported on enzymes required for the synthesis of linoleic (6% of FA) and eleostearic (80%) acids and here describe the cloning and functional analysis of an omega-3 FA desaturase (FAD3) required for the synthesis of linolenic acid (1%). The tung FAD3 cDNA was identified by screening a tung seed cDNA library using the polymerase chain reaction and degenerate primers encoding conserved regions of the FAD3 enzyme family. Expression of this cDNA in yeast cells, cultured in the presence of linoleic acid, resulted in the synthesis and accumulation of linolenic acid, which accounted for up to 18% w/w of total cellular FA. Tung FAD3 activity was significantly affected by cultivation temperature, with the greatest amount of linolenic acid accumulating in yeast cells grown at 15°C. The amount of linolenic acid synthesized in yeast cells by tung FAD3 is ca. 10-fold higher than that observed by expression of a rapeseed (Brassica napus) FAD3 in yeast, suggesting that tung FAD3 might be useful for biotechnological production of omega-3 FA in transgenic organisms.     

Genotype and Growing Environment Effects on the Tocopherols and Fatty Acids of <Emphasis Type="Italic">Brassica napus</Emphasis> and <Emphasis Type="Italic">B. juncea</Emphasis>

The effects of genotype and growing environment on the tocopherols and fatty acids (FA) of experimental Brassica juncea and B. napus breeding lines were investigated. For both species, with the exception of a few genotypes, the concentration ratio of γ-tocopherols to α-tocopherol was practically constant. The genotype influenced the tocopherol concentration in B. napus, and to a lesser degree, B. juncea. The environment also had a similar effect, and a positive correlation existed between the daily maximum temperature and the α-tocopherol concentration in B. napus. Genotype effects on the FA composition were significant for the conventional but not for Clearfield or triazine tolerant traits of B. napus. The genotype had no effect on the FA of the B. juncea genotypes. In contrast, the growing environment had a significant influence on the FA composition of both species with apparent influence from temperature and rainfall. For both species, the concentration of γ-tocopherol as well as total tocopherols was inversely related to the 18:3 concentration, which could have resulted from opposite and independent effects of temperature on the two variables. No relationship existed between the concentrations of tocopherol and the remaining unsaturated FA 18:1 and 18:2. The positional distribution of unsaturated FA within the oil triacylglycerol was a function of their total concentration.     

Use of <Emphasis Type="Italic">Rhizopus delemar</Emphasis> lipase as compared with other lipases for determination of <Emphasis Type="Italic">sn</Emphasis>-2 fatty acids in triacylglycerol

The FA composition in the sn-2 position of TAG is routinely determined after porcine pancreatic lipase hydrolysis. However, the content of saturated FA increased when a pancreatic lipase preparation with higher specific activity was used. Lipase from Rhizopus delemar was selected as a potential replacement lipase for the following reasons: (i) The FA specificity is nearly equivalent in hydrolysis activity toward FA such as lauric, myristic, palmitic, palmitoleic, stearic, oleic, linoleic, and α-linolenic acids; and (ii) lipase from R. delemar hydrolyzes fatty acyl residues at the sn-1,3 positions of TAG. Acyl migration products were present at less than 0.8% in lipase hydrolysates containing 6–14% of sn-2 MAG. A reproducibility CV of less than 5% was obtained in a collaborative study in which the compositions of the main FA at the sn-2 position in olive oil were determined using lipase from R. delemar. This article was presented in part at the Biocatalysis Symposium, 94th AOCS Annual Meeting & Expo, Kansas City, Missouri, May 2003.     

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.     

Preparation of plastic fats with zero <Emphasis Type="Italic">trans</Emphasis> FA from palm oil

A series of plastic fats containing no trans FA and having varying melting or plastic ranges, suitable for use in bakery, margarines, and for cooking purposes as vanaspati, were prepared from palm oil. The process of fractionating palm oil under different conditions by dry and solvent fractionation processes produced stearins of different yields. Melting characteristics of stearin fractions varied depending on the yield and the process. The lower-yield stearins were harder and had a wider plastic range than those of higher yields. The fractions with yields of about 35% had melting profiles similar to those of commercial vanaspati. The plastic range of palm stearins was further improved by blending them with corresponding oleins and with other vegetable oils. The plasticity or solid fat content varied depending on the proportion of stearin. Blends with higher proportions of stearins were harder than those with lower proportions. the melting profiles of some blends, especially those containing 40–60% stearin of about 25% yield and 40–60% corresponding oleins or mahua or rice bran oils, were similar to those of commercial vanaspati and bakery shortenings. These formulations did not contain any trans FA, unlike those of commercial hydrogenated fats. Thus, by fractionation and blending, plastic fats with no trans acids could be prepared for different purposes to replace hydrogenated fats, and palm oil could be utilized to the maximum extent.     

FA composition of the oil extracted from farmed atlantic salmon (Salmo salar L.) viscera

The FA composition of visceral oil extracted from farmed Atlantic salmon (Salmo salar L.) viscera was studied. Seventeen FA were identified in the extracted visceral oil, and the major FA were 18∶1n9, 16∶0, 16∶1n7, 20∶5n3 (EPA), 14∶0, and 22∶6n3 (DHA). The percentages of saturated, monounsaturated, and polyunsaturated FA in the total FA were 31.7, 36.0, and 32.2%, respectively. Compared with other fish oils, oil from farmed Atlantic salmon had much higher EPA (1.64 g/100 g) and DHA (1.47 g/100 g) contents. The FA profile of the salmon visceral oil was similar to that of the salmon fillet. Thus, the salmon visceral oil could be a replacement for the oil obtained from edible salmon fillet and used in functional foods or feeds requiring a high level of omega-3 FA. Furthermore, producing visceral oil is also beneficial to salmon fish industry by adding value back to the processing waste.     

Genetic diversity for lipid content and fatty acid profile in rice bran

Rice (Oryza sativa L.) bran contains valuable nutritional constituents, which include lipids with health benefits. A germplasm collection consisting of 204 genetically diverse rice accessions was grown under field conditions and evaluated for total oil content and fatty acid (FA) composition. Genotype effects were highly statistically significant for lipid content and FA profile (P<0.001). Environment (year) significantly affected oil content (P<0.05), as well as stearic, oleic, linoleic, and linolenic acids (all with P<0.01 or lower), but not palmitic acid. The oil content in rice bran varied relatively strongly, ranging from 17.3 to 27.4% (w/w). The major FA in bran oil were palmitic, oleic, and linoleic acids, which were in the ranges of 13.9–22.1, 35.9–49.2, and 27.3–41.0%, respectively. The ratio of saturated to unsaturated FA (S/U ratio) was highly related to the palmitic acid content (r ²=0.97). Japonica lines were characterized by a low palmitic acid content and S/U ratio, whereas Indica lines showed a high palmitic acid content and a high S/U ratio. The variation found suggests it is possible to select for both oil content and FA profile in rice bran.     

Triacylglycerol composition of oil from <Emphasis Type="Italic">Pistacia atlantica</Emphasis> fruit growing in Algeria

The distribution of FA between the sn-2 and sn-1,3 positions of TAG from Pistacia atlantica fruit oil of Algeria has been determined. Unsaturated FA showed a preference for the internal position. Linoleic and oleic acids occurred predominantly in the sn-2 position with lesser amounts evenly distributed between the sn-1 and sn-3 positions, as generally found in vegetable oils. The oil was found to contain TAG that were trisaturated (0.93%), disaturated (15.06%), monosaturated (44.64%), and triunsaturated (38.10%). The distribution of the TAG calculated using the lipase hydrolysis technique is slightly different from that determined with HPLC. This is particularly true for trioleoyl and trilinoleoylglycerols. In contrast, the agreement between theory and experiment is good for TAG containing two palmitoyl and one oleoyl, one oleoyl and two linoleoyl, and one palmitoyl and two oleoyl chains.     

Purification of Arachidonic acid from <Emphasis Type="Italic">Mortierella</Emphasis> single-cell oil by selective esterification with <Emphasis Type="Italic">Burkholderia cepacia</Emphasis> lipase

Purification of arachidonic acid (AA) from Mortierella alpina single-cell oil was attempted. The process comprised three steps: (i) preparation of FFA by nonselective hydrolysis of the oil with Alcaligenes sp. lipase; (ii) elimination of long-chain saturated FA from the resulting FFA by urea adduct fractionation; and (iii) enrichment of AA through lipase-catalyzed selective esterification with lauryl alcohol (LauOH). In the third step, screening of industrially available lipases indicated that Burkholderia cepacia lipase (Lipase-PS, Amano Enzyme Inc., Aichi, Japan) acted on AA more weakly than on other FA and was the most effective for enrichment of AA in the FFA fraction. When the FFA obtained by urea adduct fractionation were esterified with 2 molar equivalents of LauOH at 30°C for 16 h in a mixture with 20% water and 20 units (U)/g-mixture of Lipase-PS, the esterification reached 39% and the content of AA in the FFA fraction was raised from 61 to 86 wt%. To further increase the content of AA, unesterified FFA were allowed to react again under the same conditions as those in the first selective esterification except for the use of 50 U/g Lipase-PS. A series of procedures raised the content of AA to 97 wt% with a 49% recovery based on the initial content in the single-cell oil. These results indicated that the three-step process for selective esterification with Lipase-PS was effective for purifying AA from the single-cell oil.     

<Emphasis Type="Italic">Trans</Emphasis> FA content in Danish margarines and shortenings

Margarines and shortenings have been major contributors to the intake by humans of the probably atherogenic trans FA (TFA). In 1999, all 73 brands of margarines and shortenings on the Danish market were analyzed by GLC on a 50-m highly polar capillary column, and the results were compared with similar investigations in 1992 and 1995. A gradual decline of TFA in Danish margarines was observed. From 1992 to 1995, a reduction of TFA from 10.4 to 3.6% took place in margarines with 20–40% linoleic acid. In 1999, TFA was practically absent in all the margarines, but it remained unchanged in shortenings, averaging about 6–7%. Long-chain TFA from hydrogenated fish oil, although present in 13 brands in 1995, were not found at all in the 1999 samples. Trans-linoleic acids or CLA were not found. The reduction in TFA content in margarines has not resulted in a systematic change over the years in the content of saturated FA, monounsaturated FA, or PUFA. Calculated from sales figures, the intake of TFA decreased from 2.2 g per capita per year in 1992, to 1.5 g in 1995, and to 0.4 g in 1999.     

Precision of low trans fatty acid level determination in refined oils. Results of a collaborative capillary gas-liquid chromatography study

The results of a collaborative study by 38 laboratories were analyzed statistically to calculate the precision of a novel capillary gas-liquid chromatography (GLC) method for the determination of low levels of trans fatty acids (TFA) in edible oils. The participants came from 17 countries, mainly European, and were spread evenly between Unilever companies and external laboratories. All participants used the same GLC method, including a temperature optimization step, which is suitable for the determination of a large range of TFA levels in refined oils and fats and for the determination of total saturated fatty acid, cis mono- and cis-cis methylene-interrupted polyunsaturated fatty acid isomers. For TFA levels down to 0.5%, the collaborative study yielded values for R_within that ranged from 0.08 to 0.13% (absolute values) and for R_between from 0.2 to 0.4%, depending on the isomer distribution in a particular edible oil. The proposed GLC method allows reliable TFA analysis at low levels that is suitable for monitoring oil processing practices and intake control.     

Fatty acid variation in seed oil amongOcimum species

Content, fatty acid composition, and glyceride profile of oil from seeds of seven basil (Ocimum sp.) chemotypes were determined. The species studied includedO. basilicum, O. canum, O. gratissimum, andO. sanctum. The oil content ranged from 18 to 26%, with triglycerides comprising between 94 and 98% of extracted neutral lipids. The major acylated fatty acids were linolenic (43.8–64.8%), linoleic (17.8–31.3%), oleic (8.5–13.3%), and palmitic acid (6.1–11.0%). Linolenic acid was similar among the fourO. basilicum chemotypes (57–62%), highest inO. canum (65%), and lowest inO. sanctum (44%). Basil seed oil appears suitable as an edible oil or can be used for industrial purposes, and could be processed in the same way as linseed oil. Preliminary calculations estimate that a hectare of basil could produce from 300 to 400 kg of seed oil.     

Fatty Acid Composition of Turkish <Emphasis Type="Italic">Rhododendron</Emphasis> Species

This study describes work aimed at the rapid evaluation of the fatty acid (FA) composition of Turkish Rhododendron species, particularly the leaves and the flowers of the toxic plants, R. ponticum and R. luteum. The FA profiles of the available parts of three other nonpoisonous Rhododendron species were also investigated. Subtotal extracts obtained (using n-hexane, chloroform and methanol) from total chloroform:methanol (1:1) extracts were analyzed and compared to each other. Palmitic acid was found to be the most abundant FA in almost all Rhododendron extracts, and the majority of leaf and flower extracts contained significant portions of C18 unsaturated FAs (18:1n-9, 18:2n-6, 18:3n-3). The n-hexane extracts of R. ponticum leaves and R. luteum flowers were unique, as they contained an unusual series of even-chain iso FAs (C16–C24). Especially the n-hexane extracts were found to comprise uncommon FAs with odd-numbered carbons (C13–C29). Overall, n-hexane proved to be the best solvent by representing the richest FA profile, whereas chloroform or methanol appeared less suitable for FA analyses. Appreciable intra-species variations in FA compositions among the leaves as well as other anatomical parts examined were observed. This study highlights the chemotaxonomical importance of the FAs for the genus Rhododendron.     

New utilization of vegetable oils

Energy crisis and growing fuel shortage is a global concern. This phenomenon is more conspicuous in the populous, developing countries. In order to look for alternatives and extenders to the conventional fuels, studies were performed on the seed oil of some relatively unknownPutranjiva roxburghii, a plant that is abundantly available in the Indian tropical subcontinent. In a prototype experiment, the physicochemical properties of theP. roxburghii seed oil were found to be suitable for blending with diesel up to 50% without any sacrifice in performance of an internal combustion engine. Another industrially useful material, factice (vulcanized oil), was also prepared from the same oil. It was found to be suitable for blending with rubber, improving its strength, hardness, viscosity, and scorch time, and also increased its degradation temperature. This oil is not commercially traded in the market and has not yet been recommended as edible; hence industrial exploitation will not affect consumer market directly. A few more preliminary experiments indicated that the by-product oilcake is a good plant nutrient and the oil exerts profound antifungal activity. These properties need to be investigated more extensively. This plant and its oilseed deserve further attention and investigation, particularly in the tropical, coastal developing countries.