European Journal of Lipid Science and Technology

Published by Wiley-VCH Verlag
Online ISSN: 1438-9312
Print ISSN: 1438-7697
Lecitase® Ultra, a phospholipase, was explored as an effective biocatalyst for direct esterification of glycerol with oleic acid to produce 1,3-DAG. Experiments were carried out in batch mode, and optimal reaction conditions were evaluated. In comparison with several organic solvent mediums, the solvent-free system was found to be more beneficial for this esterification reaction, which was further studied to investigate the reaction conditions including oleic acid/glycerol mole ratio, temperature, initial water content, enzyme load, and operating time. The results showed that Lecitase® Ultra catalyzed a fast synthesis of 1,3-DAG by direct esterification in a solvent-free medium. Under the optimal reaction conditions, a short reaction time 1.5 h was found to achieve the fatty acid esterification efficiency of 80.3 ± 1.2% and 1,3-DAG content of 54.8 ± 1.6 wt% (lipid layer of reaction mixture mass). The reusability of Lecitase® Ultra was evaluated via recycling the excess glycerol layer in the reaction system. DAG in the upper lipid layer of reaction mixture was purified by molecular distillation and the 1,3-DAG-enriched oil with a purity of about 75 wt% was obtained. Practical applications: The new Lecitase® Ultra catalyzed process for production of 1,3-DAG from glycerol and oleic acid described in this study provides several advantages over conventional methods including short reaction time, the absence of a solvents and a high product yield.
Mean and median TFA proportion of all analysed food categories (% FAME) (––– median, – – – mean, x represents values outside the 10th and 90th percentile).
FA distribution of foods of the German market (% of FAME); food categories: I. semi-solid fats and II. deep-fried potato products.
The individual trans C18:1 distribution of different food categories and their subgroups (% of total trans C18:1). *Significantly different to the other individual trans C18:1 isomers with no asterisk within a subgroup (p ≤ 0.05).
Total fat (% fresh matter), TFA and CLA contents (% of FAME) of subgroups of the confectioneries
To determine trans fatty acid (TFA) distribution of contemporary foods, especially regarding individual trans octadecenoic acids (trans C18:1), 339 German foods of six categories (semi-solid fats, deep-fried potato products, bakery products, confectioneries, instant products and butter) were analysed using two GC methods. Results showed a high variation of TFA content between and within the categories containing between 0 and 40.5% of FAME except in butter, which is a source of natural TFA. The mean TFA values were below 2.0% of FAME, however, bakery products contained 4.5% and butter fat 3.2%, respectively. In addition, the distribution of individual trans C18:1 differed. In samples containing ruminant fat (butter and various confectioneries), vaccenic acid (t11-C18:1, t11) predominated, while in foods containing industrially hydrogenated fats, elaidic acid (trans-9, t9-) and t10-C18:1 were the major trans isomers.. This was reflected by a low t9/t11 index of 0.3 and 0.5 in butter and ruminant fat containing confectioneries, respectively, whilst the highest index was observed in shortenings and deep-fried potato products at 5.2 and 6.8, respectively. In conclusion, the TFA content of foods available on the German market is generally declining, but substantial variations are present. The t9/t11 index could be used as an indicator to determine ruminant fat.
Various plant seeds have received little attention in fatty acid research. Seeds from 30 species mainly of Boraginaceae and Primulaceae were analysed in order to identify potential new sources of the n-3 PUFA α-linolenic acid (ALA) and stearidonic acid (SDA) and of the n-6 PUFA γ-linolenic acid (GLA). The fatty acid distribution differed enormously between genera of the same family. Echium species (Boraginaceae) contained the highest amount of total n-3 PUFA (47.1%), predominantly ALA (36.6%) and SDA (10.5%) combined with high GLA (10.2%). Further species of Boraginaceae rich in both SDA and GLA were Omphalodes linifolia (8.4, 17.2%, resp.), Cerinthe minor (7.5, 9.9%, resp.) and Buglossoides purpureocaerulea (6.1, 16.6%, resp.). Alkanna species belonging to Boraginaceae had comparable amounts of ALA (37.3%) and GLA (11.4%) like Echium but lower SDA contents (3.7%). Different genera of Primulaceae (Dodecatheon and Primula) had varying ALA (14.8, 28.8%, resp.) and GLA portions (4.1, 1.5%, resp.), but similar amounts of SDA (4.9, 4.5%, resp.). Cannabis sativa cultivars (Cannabaceae) were rich in linoleic acid (57.1%), but poor in SDA and GLA (0.8, 2.7%, resp.). In conclusion, several of the presented plant seeds contain considerable amounts of n-3 PUFA and GLA, which could be relevant for nutritional purposes due to their biological function as precursors for eicosanoid synthesis.
Fatty acids are a major fuel for many tissues and abnormal utilization is implicated in diseases. However, tissue fatty acid oxidation has not been determined reliably in vivo. Furthermore, fatty acid oxidation has not been partitioned into intracellular and extracellular components. In this report, a one-pool model is described that enables direct quantitation of fluxes of intracellular and plasma fatty acids to mitochondria in skeletal muscle using dual stable isotopes and liquid chromatography/electrospray ionization ion-trap tandem mass spectrometry (LC/ESI-itMS(2)) technology. It is validated by the determination of palmitate oxidation by skeletal muscle in lean and obese rats and the regulation by insulin. Resting postabsorptive intramyocellular and plasma palmitate oxidation by gastrocnemius muscle was determined to be 3.47±0.8 and 2.06±0.5 nmol/g min in lean and 6.96±1.8 and 1.34±0.2 nmol/g min in obese rats, respectively. In obese rats, hyperinsulinemia (1 nmol/l) suppressed intramyocellular (by 59±5% to 2.88±0.3 nmol/g min P<0.05) but not plasma (1.41±0.14 nmol/g min, P>0.05) palmitate oxidation. The fractional turnover rate of palmitoylcarnitine (0.34±0.1/min vs. 0.83±0.2/min, P<0.05) was also suppressed by insulin. In obese and lean rats, there are 83% and 51%, respectively (P=0.08), of plasma fatty acids traverse triglyceride pool before being oxidized. The results demonstrated that the methodology is feasible and sensitive to metabolic alterations and thus can be used to study fatty acid utilization at tissue level in a compartmentalized manner for the firs time.
Polyisoprenylation is a set of secondary modifications involving proteins whose aberrant activities are implicated in cancers and degenerative disorders. The last step of the pathway involves an ester-forming polyisoprenylated protein methyl transferase- and hydrolytic polyisoprenylated methylated protein methyl esterase (PMPMEase)-catalyzed reactions. Omega-3 and omega-6 PUFAs have been linked with antitumorigeneis and tumorigenesis, respectively. PUFAs are structurally similar to the polyisoprenyl groups and may interfere with polyisoprenylated protein metabolism. It was hypothesized that PUFAs may be more potent inhibitors of PMPMEase than their more polar oxidative metabolites, the prostaglandins. As such, the relative effects of PUFAs and prostaglandins on PMPMEase could explain the association between cyclooxygenase-2 (COX-2) expression in tumors, the chemopreventive effects of the non-steroidal anti-inflammatory (NSAIDs) COX-2 inhibitors and PUFAs. PUFAs such as AA, EPA, and DHA inhibited PMPMEase activity with Ki values of 0.12–3.7 µM. The most potent prostaglandin was 63-fold less potent than AA. The PUFAs were also more effective at inducing neuroblastoma cell death at physiologically equivalent concentrations. The lost PMPMEase activity in AA-treated degenerating cells was restored by incubating the lysates with COX-1 or COX-2. PUFAs may thus be physiological regulators of cell growth and could owe these effects to PMPMEase inhibition.
Antioxidant properties of mono- and dihydroxyphenolic acids and their alkyl esters were examined, with emphasis on the relationship between their molecular structure and antioxidant activity. Test media with different tocopherol level were used for determining the oxidative stability: original refined sunflower oil (total tocopherols 149.0 mg/kg), partially tocopherol-stripped sunflower oil (total tocopherols 8.7 mg/kg) and distilled fatty acid methyl esters (FAME) as a tocopherol-free medium. The chemical reaction of tocopherols with diazomethane tested for the purpose to eliminate their antioxidant activity failed due to the negligible degree of methylation of hydroxyl group in the tocopherol molecule. Caffeic acid and protocatechuic acid (3,4-dihydroxyphenolic acids) and their alkyl esters were found to be more active antioxidants than monohydroxyphenolic acid (p-hydroxybenzoic acid), 2,5-dihydroxyphenolic acid (gentisic acid), 3-methoxy-4-hydroxyphenolic acids (vanillic and ferulic acids) and their corresponding alkyl esters. Naturally present tocopherols in refined sunflower oil proved to have a synergistic effect on gentisic acid but not on its alkyl esters. In contrast, tocopherols showed an antagonistic effect on alkyl esters of caffeic acid, because their protection factors decreased with increasing level of tocopherols in the test medium. Moreover, the antioxidant activity of these alkyl esters decreased with increasing length of their alkyl chain in conformity with the polar paradox hypothesis. Tocopherols as naturally present antioxidants influence considerably the antioxidant activity of other antioxidants added to plant oils used as a test medium. Distilled fatty acid methyl esters prepared from refined sunflower oil may serve as an optimal tocopherol-free test medium. Some alkyl esters of phenolic acids were evaluated to be applicable as natural more lipophilic antioxidants in comparison with phenolic acids.
Sphingolipidomics, a branch of lipidomics, focuses on the large-scale study of the cellular sphingolipidomes. In the current review, two main approaches for the analysis of cellular sphingolipidomes (i.e. LC-MS- or LC-MS/MS-based approach and shotgun lipidomics-based approach) are briefly discussed. Their advantages, some considerations of these methods, and recent applications of these approaches are summarized. It is the authors' sincere hope that this review article will add to the readers understanding of the advantages and limitations of each developed method for the analysis of a cellular sphingolipidome.
NADH-cytochrome b5 oxidoreductase (Ncb5or) in endoplasmic reticulum (ER) is involved in fatty acid metabolism, and Ncb5or -/- mice fed standard chow (SC) are insulin-sensitive but weigh less than wild-type (WT) littermates. Ncb5or -/- mice develop hyperglycemia at about age 7 wk due to β-cell dysfunction and loss in association with saturated fatty acid (SFA) accumulation and manifestations of ER and oxidative stress. Here we report that when Ncb5or -/- mice born to heterozygous mothers fed a high fat (HF) diet continue to ingest HF, they weigh as much as SC-fed WT at age 5 wk. By age 7 wk, diabetes mellitus develops in all HF-fed versus 68% of SC-fed Ncb5or -/- mice. Islet β-cell content in age 5-wk Ncb5or -/- mice fed HF for 7 days is lower (53%) than for those fed SC (63%), and both are lower than for WT (75%, SC, vs. 69%, HF). Islet transcript levels for markers of mitochondrial biogenesis (PGC-1α) and ER stress (ATF6α) are higher in Ncb5or -/- than WT mice but not significantly affected by diet. Consuming a HF diet exacerbates Ncb5or -/- β-cell accumulation of intracellular SFA and increases the frequency of ER distention from 11% (SC) to 47% (HF), thus accelerates β-cell injury in Ncb5or -/- mice.
In this paper subcritical co-solvents extraction (SCE) of algal lipid from wet pastes of Nannochloropsis sp. is examined. The influences of five operating parameters including the ratio between ethanol to hexane, the ratio of mixed solvents to algal biomass (dry weight), extraction temperature, pressure, and time were investigated. The determined optimum extraction conditions were 3:1 (hexane to ethanol ratio), 10:1 ratio (co-solvents to microalgae (dry weight) ratio), 90°C, 1.4 MPa, and 50 min, which could produce 88% recovery rate of the total lipids. In addition, electron micrographs of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were conducted to show that the algal cell presented shrunken, collapsed with some wrinkles and microholes after SCE extraction. The main composition of total lipids extracted under the optimum conditions was TAG which represented more than 80%. And the fatty acid profile of triglycerides revealed that C16:0 (35.67 ± 0.2%), C18:1 (26.84 ± 0.044%) and C16:1 (25.96 ± 0.011%) were dominant. Practical applications: The reported method could save energy consumption significantly through avoiding deep dewatering (for example drying). The composition of the extracted lipid is suitable for the production of high quality biodiesel.
The physical properties of the lamellar lipid-bilayer component of biological membranes are controlled by a host of thermodynamic forces leading to overall tensionless bilayers with a conspicuous lateral pressure profile and build-in curvature-stress instabilities that may be released locally or globally in terms of morphological changes. In particular, the average molecular shape and the propensity of the different lipid and protein species for forming non-lamellar and curved structures are a source of structural transitions and control of biological function. The effects of different lipids, sterols, and proteins on membrane structure are discussed and it is shown how one can take advantage of the curvature-stress modulations brought about by specific molecular agents, such as fatty acids, lysolipids, and other amphiphilic solutes, to construct intelligent drug-delivery systems that function by enzymatic triggering via curvature. Practical applications: The simple concept of lipid molecular shape and how it impacts on the structure of lipid aggregates, in particular the curvature and curvature stress in lipid bilayers and liposomes, can be exploited to construct liposome-based drug-delivery systems, e.g., for use as nano-medicine in cancer therapy. Non-lamellar-forming lysolipids and fatty acids, some of which may be designed to be prodrugs, can be created by phospholipase action in diseased tissues thereby providing for targeted drug release and proliferation of molecular entities with conical shape that break down the permeability barrier of the target cells and may hence enhance efficacy.
Industrial chemicals and materials are currently derived mainly from fossil-based raw materials, which are declining in availability, increasing in price and are a major source of undesirable greenhouse gas emissions. Plant oils have the potential to provide functionally equivalent, renewable and environmentally friendly replacements for these finite fossil-based raw materials, provided that their composition can be matched to end-use requirements, and that they can be produced on sufficient scale to meet current and growing industrial demands. Replacement of 40% of the fossil oil used in the chemical industry with renewable plant oils, whilst ensuring that growing demand for food oils is also met, will require a trebling of global plant oil production from current levels of around 139 MT to over 400 MT annually. Realisation of this potential will rely on application of plant biotechnology to (i) tailor plant oils to have high purity (preferably >90%) of single desirable fatty acids, (ii) introduce unusual fatty acids that have specialty end-use functionalities and (iii) increase plant oil production capacity by increased oil content in current oil crops, and conversion of other high biomass crops into oil accumulating crops. This review outlines recent progress and future challenges in each of these areas.
The “Joint Committee for the Analysis of Fats, Oils, Fatty Products, Related Products and Raw Materials (GAFett)” has developed the following method for the determination of the content of monoglycerides, diglycerides, triglycerides and glycerol in fats and fat derivatives. It is intended to include this method in Section C, Chapter VI of the German Standard Methods.
A method for the determination of total 3-chloropropane-1,2-diol (3-MCPD) in edible fats and oils was presented. 3-MCPD was released from 3-MCPD fatty acid esters by transesterification with NaOCH3/methanol. After derivatization with phenylboronic acid, 3-MCPD was determined by GC-MS. Deuterium-labeled 3-MCPD was used as internal standard. In a model experiment, it was shown that acidic hydrolysis with methanol/sulfuric acid, which is normally used for the release of 3-MCPD from its esters, can cause problems because under acidic conditions additional 3-MCPD can be formed. No additional 3-MCPD was formed using NaOCH3/methanol for transesterification. Eleven samples of cold-pressed and refined safflower oils were analyzed with this method. Levels of total 3-MCPD were in the range from <100 up to 3200 µg/kg.
Although chloropropanols have historically been associated with the savoury food ingredient hydrolyzed vegetable protein (HVP), prepared by acid hydrolysis, the discovery of significant amounts of 3-chloropropane-1,2-diol (3-CPD) ‘bound’ as fatty acid esters in foodstuffs (3-CPD esters), especially in refined edible oils, is still a relatively recent discovery. The toxicological significance of these 3-CPD esters and their potential contribution to the dietary intake of non-esterified 3-CPD is not yet known and this review considers their likely metabolic fate in vivo. The latest developments in methods of analysis are presented while the occurrence of CPD esters and their potential formation mechanisms are discussed in detail. The generation of related compounds, possible measures of control and the future outlook are also considered. Practical application: Comprehensive and up to date information concerning the state of the art with respect to the occurrence of esters of chloropropanediols in foods presented all in one place. This concise review of toxicological aspects, methods of analysis, occurrence, formation routes and potential measures of control provides data for practical use by professionals engaged in research, surveillance, risk management and regulation of these contaminants in foods.
The structures of micelles of taurocholate (TC) have been debated for many years. According to Funasaki's model based on 2D NMR studies, anti-parallel and parallel back-to-back dimers have been proposed as two major fragments in the micellar TC. However, according to Galantini's model based on X-ray crystal structure, anti-parallel and parallel face-to-face dimers have been proposed as two major fragments in the micelle. We propose a combined model from these two models for the structures of micelles of TC and suggest that these structures are equally composed of these four dimeric fragments. Lipid molecules can only insert into back-to-back dimeric fragments but not into face-to-face dimeric fragments in the mixed micelles of TC and lipid. A short-chain analog of glycerol lipid, 1,2-ethylene-di-N-n-butylcarbamate (1), was synthesized and was mixed with the micellar TC to form the mixed micelle of TC and compound 1. From the 1H NMR spectra, the ω-methyl and β-methylene protons of compound 1 split after formation of the mixed micelle with TC. Therefore, half of the compound 1 molecules insert into the anti-parallel back-to-back dimers in the mixed micelle, and the other half of the compound 1 molecules insert into the parallel back-to-back dimers in the mixed micelle.
In 2009, the Joint Committee of DIN and DGF for the Analysis of Fats, Oils, Fatty Products, Related Products and Raw Materials (GA FETT) published the German Standard Method C-III 18 (09) – Ester-bound 3-chloropropane-1,2-diol (3-MCPD-Esters) and 3-MCPD forming substances – Determination in fats and oils by GC-MS. This method was validated in a collaborative trial organised by the Federal Institute for Risk Assessment (BfR). Following further work on bound 2,3-epoxy-1-propanol (glycidol) as a possible precursor for 3-MCPD-Esters, the German Standard method was modified in 2009 to determine ester-bound 3-chloro-1,2-propandiol and 2,3-epoxy-1-propanol. The modified DGF standard method, together with a similar method, developed by SGS Hamburg (Kuhlmann method), was validated in an international collaborative study. The results of this collaborative study are reported for vegetable fats and oils, using GC with mass spectrometric detection and two different deuterated internal standards. Altogether, 17 laboratories from 5 countries (D – E – F – HU – USA) expressed interest in participation. The test was carried out according to ISO 5725:1994 – Accuracy (trueness and precision) of measurement methods and results and the Guidelines for Collaborative Study Procedures To Validate Characteristics of a Method of Analysis (AOCS 2002). The results are reported. Practical application: For the quantitative determination of 3-MCPD- and glycidyl-esters in refined fats and oils standardised methods are not yet available. Two similar methods for the quantification of the sum of ester-bound 3-MCPD and glycidol and for ester-bound 3-MCPD alone were tested in an international collaborative trial.
The “Joint Committee for the Analysis of Fats, Oils, Fatty Products, Related Products and Raw Materials (GA Fett)” has developed the following method for the determination of isomeric diacylglycerols in virgin olive oils to detect the freshness of oils. It is intended to include this method in Section C, Chapter VI of the German Standard Methods.*
Several indirect methods have been developed for the determination of 3-chloropropane-1,2-diol (3-MCPD) esters in fat matrices, but the variation between these methods leads to an uncertainty about the comparison of the results. All the indirect methods are based on the conversion of 3-MCPD esters into free 3-MCPD upon transesterification (either in acid or alkaline solution), its purification, derivatisation and instrumental analysis. In this study, major critical factors of the methodology, particularly transesterification, salting out and the choice of internal standard, were evaluated. 3-MCPD showed low stability under the conditions of alkaline transesterification (only around 40% recovery) affecting the sensitivity of the method. Furthermore, the results obtained within the first 1–2 min were 10–20% higher than those obtained at longer (5–10 min) transesterification time. A comparison of results obtained by using two different internal standards (free or esterified form of deuterated 3-MCPD) revealed a slight overestimation (7–15%) when free deuterated 3-MCPD was used, which may be possibly explained by the different behaviour of the both forms during alkaline transesterification. The use of different salts and pH values of the reaction medium during salting out step had a major impact on the results due to the formation of additional 3-MCPD. Other compounds, like glycidyl esters, present in oil samples may be converted to 3-MCPD during this step, however, the conversion was not complete and varied substantially (12–93%) in dependence on the pH value of the medium. The method based on acid transesterification showed better selectivity and robustness.
A protocol for the measurement of bound 2-chloropropane-1,3-diol (2-CPD) and 3-chloropropane-1,2-diol 3-CPD) in foodstuffs using acid catalysed transesterification and GC/MS/MS has undergone single-laboratory validation. Validation of the method included an assessment of recovery (bias) of 3-CPD from reference 3-CPD mono- and diesters using a range of fortified and unfortified cereal, oil and potato products and participation in a EC proficiency test on 3-CPD-esters. Method repeatability was assessed by measuring bound 2- and 3-CPD present in a processed cereal product. The results indicated that the method was fit for purpose for the measurement of bound 2- and 3-CPD over concentration ranges of 40–10 000 µg/kg for oils, and 4–4000 µg/kg for foodstuffs depending on the fat content. The selectivity/robustness of the method was demonstrated by fortifying samples with ‘free’ 3-CPD, chloride ions, glycerol and glycidyl butyrate: the procedure was found to be selective for ‘bound’ 3-CPD and no adventitious formation of 2- or 3-CPD occurred during analysis. Practical applications: This method provides a single-laboratory validation of a method to measure amounts of bound 2- and 3-CPD in a wide range food. The method provides the information necessary to assist researchers engaged in the selection and validation of analytical methods to measure these contaminants in foods.
Crystallisation from acetone of 1,3-dipalmitoyl-2-oleoylglycerol (POP), tripalmitoylglycerol (PPP) and their mixtures has been studied at a range of cooling rates, determining the metastable zone width using turbidimetry. A log-log plot of the cooling rate against the maximum undercooling for POP indicated a relative insensitivity of the metastable zone width to the cooling rate. The PPP metastable zone width demonstrated a slight dependence on concentration. POP crystals were spherulitic, having a more open structure at slower cooling rates. PPP crystals were more plate-like, producing powdery, more amorphous crystals at high cooling rates. In pure POP systems, onset of crystallisation was quickly followed by rapid crystal growth. The presence of PPP markedly increased the temperature of the onset of crystallisation (by 17 °C at 8% PPP), but the temperature at which crystal growth occurred, although raised, did not increase to the same extent. The clear point of the pure systems was independent of the previous cooling rate, but this was not true in the mixed system, where it decreased with increasing cooling rate. This suggests that a greater proportion of the PPP-rich phase separates during slower cooling. The morphology of the crystals from the mixed system differed from that in the pure POP system, with just 2% PPP being sufficient to shift the structure to a more lamellar appearance. Keywords: POP, PPP, solubility, supersaturation, undercooling, metastable zone.
A model margarine was stored under a temperature fluctuation cycle of 5—20 °C until granular crystals were observed. Using information obtained from the granular crystals, the crystallization behaviors of major triacylglycerols of palm oil, 1,3-dipalmitoyl-2-oleoyl-glycerol (POP), 1-palmitoyl-2,3-dioleoyl-glycerol (POO), and their mixtures were then investigated. It was shown that in the model margarine, the POP content in the granular crystals was higher than in their surrounding materials, and the X-ray diffraction pattern of the granular crystals revealed that they were the most stable polymorph, β. 99% pure POP, POO, and their mixtures were then stored under the above-mentioned temperature cycle. POP was found to form the unstable polymorph, , when cooled rapidly from the melt. Within 24 hours transformation into the polymorph and then into the β polymorph was observed. POO was shown to transform into the β' polymorph from . When POP and POO were mixed, the β polymorph did not emerge, instead it was shown that POP and POO were both agglomerated in the mixtures, giving rise to the formation of granular crystals.
Polymorphic transformations of 1,3-distearoyl-2-oleoyl glycerol (SOS) at low temperatures (10 °C–30 °C) have been studied by time-resolved synchrotron X-ray diffraction (XRD) measurements at small and wide angles. Three structures have been identified: α-phase structure forms by quenching to 10 °C from the liquid state, a metastable structure formed simultaneously with α-phase and γ-phase formed at 30 °C during α-melt-mediated crystallisation as well as at the pre-melting temperature (22.5 °C) of the α-phase when the coexistence of two phases (α and γ) is observed. The metastable structure produces three broad peaks in XRD patterns at small angles (one strong and two weak peaks corresponding to d-spacings of ∼4 nm, ∼12 nm and ∼1.5 nm respectively) and a peak in X-ray diffraction patterns at wide angles (0.42 nm). A model is proposed for the metastable structure based on a combination of double- and triple-chain packing of SOS molecules due to the similar length of alkyl chains (stearoyl and oleoyl) in the molecules.
Today, glycerol is mainly a by-product of fat splitting and biodiesel production. Further growth of the biodiesel market would result in a fall in the price of glycerol. Particularly glycerol-water from rapeseed oil methyl ester production, for example, would be an interesting raw material if it could be utilised in fermentation without further pretreatment. Under anaerobic conditions, bacteria can transform glycerol into 1,3-propanediol (PDO), which can be used as a monomer in the chemical industry. PDO can be produced biotechnologically from glycerol with the aid of bacteria. Another way would be the utilization of glucose instead of glycerol, which would provide independence from the fluctuating glycerol market. However, under certain conditions, the classic technique based on glycerol can be quite interesting with regard to technical and economic aspects: A concerted, extensive search for new microorganisms (screening) and improved process design (fed-batch with pH-controlled substrate dosage) allowed the product concentrations, which were relatively low at a maximum of 70–80 g/L as a result of product inhibition, to be raised to more than 100 g/L. An additional advantage of the new technique and the newly isolated strains is the utilisation of low-priced crude glycerol or glycerol-water. This is a factor which should not be underestimated and has a direct effect on the product costs. Further on, the use of immobilised cells compared to freely suspended cells enables an increase of productivity from about 2 up to 30 g /Lh.
The objective of our studies was to verify the potential health-related, anti-atherogenic potency of CLA isomers, fed to apolipoprotein E and LDL receptor double knockout mice (apoE/LDLR-/-), representing a reliable model of atherogenesis. Additionally, the effect of CLA isomers on liver steatosis was observed. In a "long experiment" (LONG), 2-month-old mice with no atherosclerosis were randomly assigned to three experimental groups and fed for the next 4 months. In a "short experiment" (SHORT), 4-month-old mice, with pre-established atherosclerosis, were randomly assigned to three experimental groups and fed for the next 2 months. The experimental diets were: AIN-93G (control), AIN-93G + 0.5% trans-10,cis-12 CLA (t10,c12), and AIN-93G + 0.5% cis9,trans-11 CLA (c9,t11). In both experiments, c9, t11 CLA increased mice body weight. In mice fed t10, c12 CLA weight of liver was threefold (p<0.05) increased what was linked with hepatic steatosis observed in LONG and SHORT experiment. In LONG experiment, t10, c12 CLA significantly (p<0.05) increased plasma TAGs, whereas no such effect was observed in SHORT one. In mice receiving the CLA isomers the level of PPAR alpha and SREBP-1 mRNA in liver were significantly decreased. The expression of their target genes like ACO (PPARa) or FAS (SREBP-1) were not changed. Only c9, t11 increased ACO level in LONG experiment. There were no isomer-specific effects of CLA isomers on the area of atherosclerotic plaque. In conclusion, our results do not support the notion that CLA isomers supplementation to the diet has anti-atherosclerotic effects. CLA isomers have no effect on atherosclerosis in apoE/LDLR-/- mice.
We analyzed a triacylgylcerol esterified CLA preparation characteristically rich in c9,t11-CLA and free of t10,c12-CLA three times within a period of 2 years by GC and silver ion-HPLC. For the first time, we present data on the long-term stability of this preparation with regard to the fatty acid profile and the isomeric composition of CLA under certain storage conditions, providing useful information for the planning of long-term trials.
The suitability of 13C NMR as a primary method for the analysis of lipids to obtain nutritional labeling compositional data (NLCD), i.e. the percentages of saturated, cis-monounsaturated, trans-monounsaturated, and cis-polyunsaturated fat, was assessed. The 13C NMR methodology was developed by using mixtures of pure triglycerides as model lipids to optimize and standardize scan conditions and spectral pre-processing procedures, establish fixed integration limits for measurement of the 13C resonances used in the determination of NLCD, and evaluate the quantitative accuracy of the 13C NMR analysis. The standardized 13C NMR methodology allowed the NLCD of the model triacylglycerol mixtures to be determined within ˜±1%. To further evaluate the methodology, two sets of validation samples, consisting of ten unhydrogenated oils from the American Oil Chemists' Society Laboratory Proficiency Program (AOCS-LPP) and two trans-containing AOCS-LPP samples combined with three samples from a hydrogenation process, were analyzed. Good overall agreement between the NMR-determined NLCD (in units of mol-%) and the mol-% NLCD calculated for these samples from fatty acid compositional data obtained by gas chromatography was found, including good tracking of the trans content in the second validation set. Given that the NLCD must be expressed on a wt-% basis to be of practical utility, a means of mol-% to wt-% conversion was developed assuming all unsaturates to be C18 and obtaining the weight-average molecular weight of the saturated fatty acid contributions from the NMR data. This conversion was shown to be especially effective for oil blends, where errors become significant if unit conversion is not done. This work indicates that 13C NMR can provide excellent primary NLCD data, even in wt-% terms, which can be used for calibrating simpler and automatable instrumental methods such as FTIR spectrometers to determine or screen for NLCD for fats and oils or lipids extracted from food on a routine basis.
The nutrition labeling compositional data (NLCD) required for fat-containing food products consists of the percentages of saturated, cis-monounsaturated, and cis-polyunsaturated fat as well as trans content. The capability of 1H NMR spectroscopy to determine the NLCD components in oils that do not contain significant levels of trans isomers has already been established in the literature, but not its capability to differentiate between cis- and trans-unsaturation. In the present study, the determination of all four NLCD components in fats and oils has been demonstrated for the first time. A preliminary analysis of the intensity-normalized 1H NMR spectra of defined mixtures of pure triacylglycerols (TAG) by partial least squares (PLS) regression revealed that the (mono)allylic proton resonances of cis and trans bonds were sufficiently well separated to allow for accurate quantitation of trans content by simple peak integration. This chemometric approach also served to facilitate the identification of optimal integration limits for these cis- and trans-allylic resonances. Fixed integration limits were also set for the other resonances employed in the determination of the four NLCD components, and a standardized spectral preprocessing procedure was established. The 1H NMR NLCD data obtained for the TAG mixtures by this methodology was a good match to the actual values, calculated from the known molar composition of these gravimetrically prepared mixtures. A procedure for the conversion of the NMR mol% NLCD to units of wt%, previously developed for 13C NMR, was adapted for 1H NMR and shown to be effective in compensating for the overestimation of wt% saturates and underestimation of wt% unsaturates by 1H NMR if this conversion is not made. The 1H NMR methodology for NLCD determination was validated by analyzing AOCS Laboratory Proficiency Program GC samples as well as samples taken from a hydrogenator over time and analyzed for trans content by GC and IR spectroscopy. Comparison of the 1H NMR mol% and wt% NLCD obtained for these validation samples with the data obtained from the reference methods indicated that 1H NMR can deliver high-quality, accurate NLCD, much like 13C NMR, but in a much shorter time frame. Thus, 1H NMR provides a more rapid and cost-effective means of obtaining NLCD than 13C NMR and can replace GC as a primary reference method for the calibration of simpler and automatable instrumental methods such as Fourier transform infrared (FTIR) spectroscopy.
The asymmetric Sharpless epoxidation of methyl 13S-hydroxy-9Z, 11E-octadeca-dienoate (13S-HODE, 1) with tert-butyl hydroperoxide (TBHP) catalysed by titanium tetraisopropoxide {Ti(iOPr)4} in the presence of L(+)-diisopropyl tartrate (L-DIPT) gave methyl 13S-hydroxy-11S, 12S-epoxy-9Z-octadecenoate 2 (erythro isomer) in 84% diastereomeric excess (de). The epoxidation of 1 with TBHP catalysed by Ti(iOPr)4 in the presence of D(-)-DIPT yielded methyl 13S-hydroxy-11RR12R-epoxy-9Z-octadecenoate (threo isomer) 3 in 76% de.
Biodegradation of waste cooking oil and its application as lipase production inducer in cultures of Yarrowia lipolytica CECT 1240 have been investigated, both in shake flasks and a bench-scale bioreactor. The ability of this strain to degrade the spent oil was evaluated by monitoring COD throughout the cultures, and a remarkable decrease was recorded (almost 90% decrease in oil COD after 3 days in bioreactor). Moreover, the addition of waste cooking oil to the medium led to a significant augmentation in extracellular lipase production by the yeast, compared to oil-free cultures. This confirms the suitability of the studied residue as an inducer of lipase biosynthesis, which is a very interesting fact, from an economic standpoint. These results were confirmed when a fed-batch strategy was proposed. Finally, some properties of the crude enzyme were studied, and compared to the enzymes obtained when non-used oil was added to the medium. Practical application: New strategies to valorize wastes from the food and agro industries are attracting a great scientific interest due to the important advantages offered from an economic and environmental point of view. For this reason, the yeast Yarrowia lipolytica CECT 1240 is proposed for degrading waste cooking oils. This approach entails also another benefit in terms of lipolytic enzyme synthesis, since the addition of used up oils has a lipase inducer effect. The enormous interest in lipases is reflected in the number of applications that they present. The process was successfully carried out both in shake flasks and a bench-scale bioreactor, allowing producing high levels of lipolytic activity at the same time that the COD was diminished up to nearly 90%.
A lipase preparation developed from Candida sp. 99-125 was used for fatty acid alkyl ester synthesis by both enzymatic esterification of fatty acids, and transesterification of oils and fats. The lipase preparation was chosen based on screening of lipases from commercial sources as well as those produced in the laboratory. The effects of enzyme dosage, solvent types, water absorbent additions, inhibition of short-chain alcohols, alcohol and acid types, molar ratio of substrates, and reusability of the lipase preparation in esterification were studied. Degree of esterification between oleic acid and methanol under optimal conditions reached 92%. Purity of the methyl ester after washing with water and distillation was 98%. Half-life of the lipase preparation was calculated to be approximately 340 h. For transesterification of rapeseed oil with the same lipase preparation, the amount of methanol and mode of methanol addition to the reaction were also conducted. Transesterification of the oil with stepwise methanol addition reached 83% after 36 h reaction time.
An enzyme from the alga Chlorella pyrenoidosa, previously identified as a hydroperoxide lyase (HPLS), cleaves the 13-hydroperoxide derivatives of linoleic and linolenic acids into a volatile C5 fragment and a C13 oxo-product, 13-oxo-9(Z),11(E)tridecadienoic acid (13-OTA). Gas chromatography/mass spectrometry (GC/MS) headspace analysis of the volatile products indicated the formation of pentane when the substrate was the 13-hydroperoxide derivative of linoleic acid, whereas a more complex mixture of hydrocarbons was formed when the 13-hydroperoxide derivative of linolenic acid was the substrate. Analysis of the nonvolatile products by GC/MS and liquid chromatography/mass spectrometry (LC/MS) indicated the formation of 13-OTA along with the 13-ketone derivative. This enzymatic activity was inhibited by oxygen but was restored with nitrogen. The enzymatic cleavage activity was coincidental in purified fractions with lipoxygenase activity that produced the 13- and 9-hydroperoxide derivatives of linolenic acid. The results suggest that the enzymatic cleavage activity in Chlorella pyrenoidosa was not a consequence of hydroperoxide lyase activity as previously thought, but was due to anaerobic lipoxygenase activity. This enzyme fraction was purified by (NH4)2 SO4 precipitation, gel filtration, and hydrophobic interaction chromatography. The purified enzyme has an approximate MW of 120 KDa and maximum activity at pH 8.0.
In this study, the tocopherol (T) and tocotrienol (T3) contents of grape seeds from 14 different varieties grown in Korea were analyzed using saponification extraction followed by normal-phase liquid chromatography. α-T, γ-T, α-T3, and γ-T3 were detected in all samples. The total concentration of tocopherol and tocotrienol was in the range of 4.8–9.9 mg/100 g seed (35.3–68.8 mg/100 g oil basis). The Muscat Bailey A cultivar had the highest total tocopherol and tocotrienol contents, followed by Canner and Naples. γ-T3 ranged from 1.6 to 4.9 mg/100 g seed (11.2 to 53.81 mg/100 g oil basis) and was the main isomer, followed by α-T3 in most of the samples. Analytical method validation parameters including accuracy and precision were determined. Overall recovery from grape seeds was close to 100%.
Position and configuration isomers of conjugated linoleic acid (CLA), from 7, 9- through 12, 14-C18:2, were synthesized by directed sequential isomerizations of a mixture of rumenic (cis-9, trans-11 C18:2) and trans-10, cis-12 C18:2 acids. Indeed, the synthesized conjugated fatty acids cover the range of unsaturated systems as found in milk fat CLA. The two-step sequence consisted in initial sigmatropic rearrangement of cis/trans CLA isomers at 200 °C for 13 h under inert atmosphere (Helium, He), followed by selenium-catalyzed geometrical isomerization of double bonds at 120 °C for 20 h under He. Product analysis was achieved by gas-liquid chromatography using a 120 m polar capillary column coated with 70% cyanoalkylpolysiloxane equivalent polymer. Migration of conjugated systems was geometrically controlled as follows: the cis-Cn, trans-Cn+2 double bond system was rearranged through a pericyclic [1, 5] sigmatropic mechanism into a trans-Cn-1, cis-Cn+1 unsaturated system, while the trans-Cn, cis-Cn+2 double bond system was rearranged through a similar pericyclic mechanism into a cis-Cn+1, trans-Cn+3 unsaturated system. Selenium-catalyzed geometrical isomerization under mild conditions then allowed cis/trans double bond configuration transitions, resulting in the formation of all cis, all trans, cis-trans and trans-cis isomers. A sequential combination of the two reactions resulted in a facile controlled synthesis of CLA isomers, useful for the chromatographic identification of milk fat CLA, as well as for the preparation of CLA standard mixture.
GC-FID chromatogram of the C ¸ akldak cultivar. 
The phytosterol contents of the oils from 17 Turkish hazelnut cultivars were determined by gas chromatography with a flame ionization detector. The total phytosterol content varied from 1180.4 (Uzunmusa-Ordu) to 2239.4 mg/kg (Cavcava), and the average was 1581.6 ± 265.1 mg/kg. One of the most significant commercial cultivars, Tombul, contained quite low total phytosterols (1297.7 mg/kg). Total and individual phytosterol contents of hazelnut cultivars were significantly different at p <0.01, except for phytostanol and campestanol. The main component was β-sitosterol which ranged from 82.8 to 86.7% in all cultivars. This was followed by campesterol, Δ5-avenasterol, sitostanol and stigmasterol. Interestingly, the same cultivars from different regions showed similar total phytosterol contents, and fall almost within the same range according to Duncan's test, which may indicate that the phytosterol content is highly related to the cultivar.
Stearidonic acid (SA, 18:4n-3) is a polyunsaturated fatty acid (PUFA) that constitutes the first metabolite of α-linolenic acid (ALA, 18:3n-3) in the metabolic pathway leading to C20–22 PUFA, such as eicosapentaenoic acid (EPA, 20:5n-3), and docosahexaenoic acid (DHA, 22:6n-3), which recently have received much attention because of their various physiological functions in the human body. Recently, several studies indicated that dietary SA increased EPA more efficiently than ALA. Thus, vegetable oils containing SA may become a dietary source of n-3 fatty acids that is more effective in increasing tissue n-3 PUFA concentrations than the current ALA-containing vegetable oils. Nevertheless, few SA sources occur in nature, although there are still a large number of species untested to date. SA has been detected in variable amounts in several species of algae, fungi and animals tissues, but the seeds of some plant families seem to be better sources of SA, especially Echium (Boraginaceae) species. This work reviews the nutritional significance, medical uses and natural occurrence of SA.
Sunflower oil (SO) is a renewable resource that can be epoxidized, and the epoxidized SO has potential uses as an environmentally friendly and reactive material in polymeric formulations, especially for polyvinyl chloride. SO was epoxidized with peracetic acid, which was either preformed or prepared in situ. In order to optimize the formation of oxirane rings, the epoxidation and the extent of the side reactions were studied at different temperatures. The peracetic acid was obtained by acidic catalysis in the presence of a cation-exchange resin. The optimum conversions were obtained within a 4-h reaction period at 55 °C by the in situ epoxidation technique. The epoxidation was also carried out with hydrogen peroxide in the presence of peroxotungstic acid complexed with lipophilic phosphorus-based ligands. 1H NMR was used to define the new indices Δ and Ω, which are the mean numbers of C=C double bonds and oxirane rings per fatty acid chain, respectively. This allowed monitoring of the reaction and quantification of the results. Peroxotungstic catalysts appeared less performing than peracids in the epoxidation of SO, but were found very efficient for the epoxidation of the SO methyl esters.
The common unsaturated fatty acids present in many vegetable oils (oleic, linoleic and linolenic acids) can be quantitated by 1H-nuclear magnetic resonance spectroscopy (1H-NMR). A key feature is that the signals of the terminal methyl group of linolenic acid are shifted downfield from the corresponding signals in the other fatty acids, permitting their separate integration and quantitation of linolenic acid. Then, using the integration values of the signals of the allylic and bis-allylic protons, oleic and linoleic acids can be quantitated. The procedure was verified for mixtures of triacylglycerols (vegetable oils) and methyl esters of oleic, linoleic and linolenic acids as well as palmitic and stearic acids. Generally, the NMR (400 MHz) results were in good agreement with gas chromatographic (GC) analyses. As the present 1H-NMR-based procedure can be applied to neat vegetable oils, the preparation of derivatives for GC would be unnecessary. The present method is extended to quantitating saturated (palmitic and stearic) acids, although in this case the results deviate more strongly from actual values and GC analyses. Alternatives to the iodine value (allylic position equivalents and bis-allylic position equivalents) can be derived directly from the integration values of the allylic and bis-allylic protons.
Several samples containing different proportions of standard compounds such as tristearin, triolein, trilinolein, and trilinolenin, covering a broad range of compositions, some similar to those of edible oils, were prepared by weight. The 1H nuclear magnetic resonance (NMR) spectra of these samples were recorded and their signals were assigned. It was shown that concentrations of linolenic acyl groups close to 0.4% or higher can be detected by this technique. The area of 5 discrete proton signals of the spectrum was determined. Considering the ratio between this area and the concentration of the corresponding types of hydrogen atoms in the sample, equations calculating the proportions of the acyl groups were deduced. The high level of agreement between data coming from 1H NMR spectra and data obtained by weight shows the usefulness of this methodology. In addition, it has the advantage that it is very fast and simple in comparison with the classical methods, and does not require a chemical modification of the sample. For this reason, the described method constitutes a valuable alternative for the determination of the proportions of different acyl groups in acylglycerol mixtures, such as, for example, oils and fats.
A new method for the parallel determination of bound 2,3-epoxy-1-propanol (glycidol) and 2- and 3-chloropropanediol (2- and 3-MCPD) in oil matrices is presented. It is based on an improved alkaline catalysed release of MCPD and glycidol, followed by a transformation of glycidol to monobromopropanediol (MBPD), derivatisation with phenylboronic acid (PBA) and analysis by GC–MS. Quantification was performed using isotopic labelled standards. Method validation was carried out for the complete method procedure using glycidyl stearate and 3-chloropropanediol-1,2-bis-palmitoyl ester as reference compounds. Linearity was verified (r²>0.999) within the concentration range from 0.1 to 5.7 mg/kg. The limit of detection (LOD) for bound glycidol was 0.025 mg/kg in absence of 3-MCPD. Due to a lack of certified reference material a validation of bound 2-MCPD analysis was not feasible, but an indirect approach yielded a semi-quantitative estimation. The method was applied to the analysis of several different oils. None of the analytes was detected in virgin or crude oils. In contrast bound MCPD and bound glycidol was detected ubiquitously in refined oils. The determined concentrations of 3-MCPD and glycidol in the tested samples varied in 2 orders and 4 orders of magnitude, respectively. Bound 2-MCPD was estimated to occur commonly in refined oils.
Trans,trans-2,4-decadienal is a by-product of frying oil that is also transferred to fried food. This aldehyde has been found and quantified both in frying oils and fumes generated during frying. Furthermore, it has been reported that 2,4-decadienal has cytotoxic and genotoxic effects and promotes LDL oxidation. In the present work trans,trans-2,4-decadienal was detected directly in fried potatoes (french-fries). Moreover, the influence of frying conditions (deep-frying, pan-frying), the oil type (olive oil, sunflower oil, cottonseed oil, palm oil and a vegetable shortening) and the degree of thermal deterioration (eight successive frying sessions without replenishment) on the production of 2,4-decadienal in oil and potatoes was studied. The isolation of the aldehyde was performed by methanol extraction, while the identification and quantification was performed by RP-HPLC. The quantity of trans,trans-2,4-decadienal produced during successive pan-frying demonstrated a peak at the third and fourth frying session. The highest concentration of trans,trans-2,4-decadienal was detected in potatoes fried in sunflower oil, and the lowest in olive oil. The quantity of trans,trans-2,4-decadienal in fried potatoes decreased during successive deep-frying at the seventh frying session or remained stable, except for cottonseed oil. The quantity of trans,trans-2,4-decadienal in fried potatoes was considered to be dependent on the oil used, on the frying process and, to a lesser extent, on the oil deterioration. In all cases tested, the highest concentration of trans,trans-2,4-decadienal was detected during deep-frying. The unsaturation degree of the frying oil was considered to promote the formation of trans,trans-2,4-decadienal. Considering the quantity of 2,4-decadienal found in french-fries and in the respective frying medium, direct quantification of 2,4-decadienal is required in order to make an estimation of intake from french-fries.
Some frying by-products of medium polarity, so-called medium-polarity materials (MPM), produced during domestic deep-frying of French-fried potatoes in edible vegetable oils, have recently been isolated and linearly correlated to % total polar materials and % polymerized triglycerides. The in vitro oxidation of low-density lipoproteins in a dose-dependent manner by MPM has also been reported. In the present study, the MPM constituents were identified after extraction of MPM from the oils, subsequent purification by RP-HPLC, and GC-MS analysis. The main constituent of MPM was trans,trans-2,4-decadienal, a compound that has previously been reported to be formed during peroxidation of linoleic and arachidonic acid. 2,4-Decadienal was also quantified in oils and fats used for frying in restaurants in Athens, Greece, by direct injection of oil sample solutions in HPLC. For the most commonly used frying oils, 2,4-decadienal concentration ranges were 0.3–119.7 mg/kg for sunflower oil, 13.3–92.7 mg/kg for cottonseed oil, 4.1–44.9 mg/kg for palm oil, and 2.0–11.3 mg/kg for vegetable cooking fats. Considering the common catering practices of frying, 2,4-decadienal was more likely to be found in sunflower oil after deep-frying of potatoes. Comparing the amounts of this aldehyde found in oils from restaurants to the amounts previously found for domestic frying (up to 30 mg/kg after the 8th successive frying session in sunflower oil), the probability of consuming a level of 2,4-decadienal in restaurant-prepared food that is higher than the level in home-fried food was determined to be approximately one third.
Computer technology has provided chemical research with many new and advanced analytical techniques. By the year 2050 computers are predicted to run a million times faster than today's machines. Scientists have remained satisfied with their studies of molecules and to dwell in the dimensions of space and matter only. The difficulty for humans to comprehend the ‘idea of time’ has kept the issue of “time” on the sideline. The human brain is an infinitely more powerful and intelligent computer than our silicon chip driven computers. For the brain to be intelligent, the ‘idea of time’ appears to play an important role. With the large amount of lipid molecules found in the brain, lipidologists are in a position to unravel this mystery of life. The development of robotics, nanotechnology and genetic engineering depends on the continued growth of computing power. Quantum computers are new concepts and there is a chance for lipidologists to mimic the brain and produce an intelligent computer system, which runs on fat molecules (‘FAT’ chips).Imagination is the mother of invention. One of the latest advances in fatty acid chemistry is the study of lipid molecules containing a [60]fullerene unit. Such futuristic molecules are viewed as potential drugs, as well as potential components for the design of the ‘FAT’ chip. The future direction of the fat, nutrition and oleochemical industry rests on demands from the consumers. By the year 2050, the average life span for men and women in the industrial countries will increase significantly to 80 for women and 75 for men. A great demand for geriatric gourmet food, nutraceuticals, cosmetics and bodycare products is to be expected. With the birth rate declining in these countries, there will also be a great demand for special infant food products — especially, mother's milk.
The “Joint Committee for the Analysis of Fats, Oils, Fatty products, Related Products and Raw Materials (GA FETT)” has developed the following method for the determination of the Solid Fat Content (SFC) in fats and oils. It is intended to include this method in Section C, Chapter IV of the German Standard Methods. The method reflexes the need of the fats and oils industry to get fast results and was tested in an interlaboratory test with 16 laboratories from 6 European countries.
The historical development of fractionation, from the use of fractionated tallow in Mège-Mouriès' margarine to the modern dry fractionation process used to produced steep-melting palm fractions for cocoa butter equivalents, is described. The principles of fractionation by fractional crystallisation are explained. The fractionation process is carried out in two stages: firstly, a crystallisation stage; secondly, a separation stage. Crystallisation may be effected without any solvent (dry fractionation) or in the presence of a solvent. It can be shown that the efficiency of separation of triglycerides is more or less independent of the solvent so that dry fractionation is, in principle, capable of giving as good a fractionation as solvent fractionation. However, separation of the solid phase (crystals) from the liquid phase is easier in the presence of a solvent, which dilutes the oil and lowers the viscosity. It is mainly developments in separation over the last 25 years that have led to the improved effectiveness of dry fractionation so that it can achieve results that rival solvent fractionation. The concept of ‘entrainment’ is explained with reference to the different separation methods and to their different efficiencies. Today, hydrogenation is in decline, due to nutritional concerns about trans fatty acids and to environmental concerns about nickel catalysts and their disposal. Increasingly, oils with reduced linolenic acid (C18:3) can be produced agriculturally so that stable frying oils may be produced without hydrogenation. With the decline in hydrogenation, interesterification has seen a renaissance, although it is only partially able to replace hydrogenation. Additionally, interesterification suffers from the ‘chemical’-process image and environmental drawbacks of hydrogenation. Fractionation is a purely physical process which satisfies today’s increasing environmental and health concerns. It is the main modification process used for palm oil, whose production is still increasing rapidly and which is likely to become the world’s most-produced oil within 10 years. If hydrogenation is to be avoided, then only palm stearins can supply the higher solid fat content components required to produce the margarines and shortenings essential to produce the bread, pastries and cakes we like to eat. Fractionation is therefore set to become the dominant modification process of the 21st century.
Oil palm is currently at a historic crossroads as regards its future prospects as a versatile global oil crop. In 2005, oil palm became the world's leading commercial source of vegetable oil, and the continued expansion of Asian economies augers well for further growth in production. There are several significant challenges that face the oil palm industry, both biological and non-biological. The major biological and managerial challenge will be to tackle the stagnating yield that has characterised average plantation output over the past decade. Yield can be enhanced by developing and efficiently propagating/distributing improved germplasm for both large plantations and smallholders. Improved biocontrol of major pests and diseases, such as Ganoderma and rhinoceros beetle, will also have a significant impact. Oil quality can be improved by diversifying fatty acid composition to produce high-oleate varieties for mainstream edible/oleochemical use, as well as other useful acyl compositions, including nutraceutical components and enhanced vitamin A and E contents for higher-value niche markets. The whole spectrum of breeding approaches, from DNA marker-assisted selection to genetic engineering, is being deployed to meet these objectives. One of the potential threats to the future growth of oil palm as a source of high-quality foods and oleochemicals is the rapid emergence of biodiesel, which might destabilise the industry in the short term and adversely impact on its image and attractiveness for longer-term investment.
The object of this paper is the development of a biotechnological process for production of rhamnolipids by Pseudomoas sp. DSM 2874. The product obtained from rapeseed oil was found to be a mixture of up to four glycolipids (rhamnolipid 1 - 4), L-(+)rhamnose and (R, R)-3-(3-hydroxydecanoyloxy) decanoic acid. An HPLC-method was developed for identification and quantification of rhamnolipids and fatty acids, using an evaporative light scattering detector. Growing cells under nitrogen limiting conditions and resting cells were used for rhamnolipid production with triglycerides as C-source. Best results and product yields (up to 45 g l-1 of mixtures of rhamnolipid 1 and rhamnolipid 3) were obtained using resting cells in a fed batch process with rapeseed oil as C-source. Product composition was found to be strongly dependent on the process conditions. Using the fungal enzyme Naringinase it was possible to cleave the glycosidic bond between the two rhamnose units of rhamnolipid 3, and the bond between L-(+)-rhamnose and (R, R)-3-(3-hydroxydecanoyloxy) decanoic acid of rhamnolipid 1. The latter reaction occurred at a much lower rate. Direct addition of Naringinase to resting cells in an integrated microbial/enzymatic process was possible and resulted in an alteration of product composition from a rhamnolipid 1 and rhamnolipid 3 mixture to rhamnolipid 1 only.
Soybean germ oil (SGO) could take an important place among nutraceuticals if the finding were confirmed that a daily intake of SGO helps to maintain a normal level of serum cholesterol. Adapting the rice milling technology to the soybean refining process, we achieved a rapid and efficient separation of soybean bran and cotyledon from the hypocotyle. Our soybean germ was no less than 95% hypocotyle. SGO obtained from it by typical hexane extraction was very rich in tocopherols (total content 4.35 g/kg) and phytosterols (β-sitosterol 57.4%, Δ-7-stigmastenol 20.2%, Δ-7-avenasterol 6.8%, stigmasterol 6.2%, campesterol 5.4%, Δ-7-campesterol 1.2%, Δ-5-avenasterol 0.95%, etc.; total sterols 44.3 g/kg). The most prominent fatty acids were linoleic (56.2%), linolenic (15.5%) and oleic acid (10.6%). Although isoflavones abound in soybean germ (17.7 g/kg), only traces of them passed into the hexane extract (7 mg/kg). In murine 3T3 fibroblasts, SGO was found to reduce the incorporation of [14C]acetate into sterols, by inhibiting oxidosqualene cyclase.
Although 4,4-dimethyloxazoline (DMOX) derivatives of fatty acids have been widely used for structural analysis of fatty acids by mass spectrometry, spectra of relatively few authentic standards have been published. Confusion can result when double bonds are located near either end of the molecule, and errors have been promulgated in the literature. Mass spectra of DMOX derivatives of the complete series of isomeric octadecenoates are described. Even when spectra are not easily interpreted mechanistically in terms of the double bond location, they usually give distinctive fingerprints.
Top-cited authors
Seraphim Papanikolaou
  • Agricultural University of Athens
George Aggelis
  • University of Patras
M. C. Dobarganes
Christian Gertz
  • Maxfry Gmbh Hagen
Joaquín Velasco
  • Spanish National Research Council