Production of conjugated linoleic acid isomers by dehydration and isomerization of castor bean oil

The possibility of combining dehydration and isomerization of castor bean oil as a means to obtain CLA as TAG forms was studied. First, dehydration was carried out using various catalysts and reaction parameters. Best results were obtained using phosphoric acid (0.1% w/w) at 280°C for 5 h. Under such conditions, satisfactory proportions of CLA were obtained (54% of total FA) with a majority of 9-cis, 11-trans isomer (61% of total CLA). Other catalysts such as bisulfate-bisulfite, sulfuric acid, tungstic and phosphotungstic acids, or resins and zeolites were also tested. With the exception of resins and zeolites, these catalysts also led to CLA production but in limited amounts in comparison with phosphoric acid. In a second step, an isomerization reaction was carried out to transform the residual nonconjugated linoleic acid also produced during dehydration into CLA. Using Wilkinson catalyst [RhCl(PPh₃)₃] in ethanol solvent, dehydrated castor bean oil was isomerized in high yields (>98%), allowing a complete disappearance of nonconjugated linoleic acids. The resulting dehydrated/isomerized oil contained more than 87% CLA with the 9-cis, 11-trans isomer being predominant (40% of CLA fraction). Finally, urea fractionation was also applied on dehydrated/isomerized castor bean oil FA to obtain FFA products containing about 93% CLA.     

Oxidation kinetics for <Emphasis Type="Italic">cis</Emphasis>-9,<Emphasis Type="Italic">trans</Emphasis>-11 and <Emphasis Type="Italic">trans</Emphasis>-10,<Emphasis Type="Italic">cis</Emphasis>-12 isomers of CLA

The autoxidation processes of the cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) isomers of CLA were separately observed at ca. 0% RH and different temperatures. The t10,c12 CLA oxidized faster than the c9,t11 isomer at all tested temperatures. The first half of the oxidation process of t10,c12 CLA obeyed an autocatalytic-type rate expression, but the latter half followed first-order kinetics. On the other hand, the entire oxidation process of c9,t11 CLA could be expressed by the autocatalytic-type rate expression. The apparent activation energies and frequency factors for the autoxidation of the isomers were estimated from the rate constants obtained at various temperatures based on the Arrhenius equation. The apparent activation energies for the CLA isomers were greater than those for the nonconjugated n−6 and n−3 PUFA or their esters. However, the enthalpyentropy compensation held during the autoxidation of both the CLA and PUFA. This suggested that the autoxidation mechanisms for the CLA and PUFA were essentially the same.     

Effects of conjugated linoleic acid, fish oil and soybean oil on PPARs (α & γ) mRNA expression in broiler chickens and their relation to body fat deposits

An experiment was conducted on broiler chickens to study the effects of different dietary fats (Conjugated linoleic acid (CLA), fish oil, soybean oil, or their mixtures, as well as palm oil, as a more saturated fat), with a as fed dose of 7% for single fat and 3.5 + 3.5% for the mixtures, on Peroxisome Proliferator-Activated Receptors (PPARs) gene expression and its relation with body fat deposits. The CLA used in this experiment was CLA LUTA60 which contained 60% CLA, so 7% and 3.5% dietary inclusions of CLA LUTA60 were equal to 4.2% and 2.1% CLA, respectively. Higher abdominal fat pad was found in broiler chickens fed with a diet containing palm oil compared to chickens in the other experimental groups (P ≤ 0.05). The diets containing CLA resulted in an increased fat deposition in the liver of broiler chickens (P ≤ 0.05). The only exception was related to the birds fed with diets containing palm oil or fish oil + soybean oil, where contents of liver fat were compared to the CLA + fish oil treatment. PPARγ gene in adipose tissue of chickens fed with palm oil diet was up-regulated compared to other treatments (P ≤ 0.001), whereas no significant differences were found in adipose PPARγ gene expression between chickens fed with diets containing CLA, fish oil, soybean oil or the mixture of these fats. On the other hand, the PPARα gene expression in liver tissue was up-regulated in response to the dietary fish oil inclusion and the differences were also significant for both fish oil and CLA + fish oil diets compared to the diets with palm oil, soybean oil or CLA as the only oil source (P ≤ 0.001). In conclusion, the results of present study showed that there was a relationship between the adipose PPARγ gene up-regulation and abdominal fat pad deposition for birds fed with palm oil diet, while no deference was detected in n-3 and n-6 fatty acids, as well as CLA on PPARγ down regulation in comparison to a more saturated fat. When used on its own, fish oil was found to be a more effective fat in up-regulating hepatic PPARα gene expression and this effect was related to a less fat deposition in liver tissue. A negative correlation coefficient (-0.3) between PPARα relative gene expression and liver tissue fat content confirm the anti-lipogenic effect of PPARα, however, the change in these parameters was not completely parallel.     

Enzyme‐catalyzed synthesis of structured phospholipids with conjugated linoleic acid

Structured phospholipids were synthesized with the functional lipid conjugated linoleic acid (CLA). The lipase‐ and phospholipase A₂‐catalyzed enzymatic acidolysis reaction between phospholipids (PL) and CLA was used for fatty acid modification. Enzymatic processes were an effective way to produce structured PL. Screening of four lipases and immobilized phospholipase A₂ and a combination of lipase and phospholipase showed that only Lipozyme RM IM and Lipozyme TL IM were effective in incorporation of CLA into PL. The maximum incorporation achieved by the latter enzyme was 16% with soy PL in 72 h.     

Long‐term conjugated linoleic acid supplementation in humans – effects on body composition and safety

In our contemporary adipogenic environment even modest improvements in body fat mass could be of relevance. In the last years animal and human studies have investigated the potential benefit of CLA on body composition. However, inconclusive results are often derived from short‐term studies. Long‐term intervention trials with supplemental CLA on body composition have not been reviewed exclusively up to now. Therefore, the objective of this study was to review the evidence of prolonged CLA supplementation as well as its influence on body composition in humans, and to summarize results from safety assessments of CLA intake. A literature search was performed to find intervention trials with CLA supplementation and its effects on body composition, as well as on insulin sensitivity. Only prolonged (≥12 wk) studies on body composition were included. The investigated studies indicate a modest reduction and/or prevention of regain of body fat in overweight/obese subjects. Results on the influence of CLA on insulin sensitivity are inconsistent, with newer data rather adding to the safety of CLA. Impaired insulin sensitivity by CLA remains a safety concern, yet is seemingly restricted to diabetic subjects and single‐isomer application. A meta‐a2 lysis of extended studies only is warranted to quantitatively evaluate the effects of CLA on body composition. Future research may elucidate if CLA should be considered as a marginal missing, semi‐essential nutrient in our present diet.     

Comparative study of the autoxidation of TAG containing conjugated and nonconjugated C<Subscript>18</Subscript> PUFA

Four TAG containing linoleate (soybean-TAG), α-linoleate (perilla-TAG), conjugated linoleate (CLA-TAG), and conjugated linolenate (bitter gourd-TAG) were oxidized in the bulk phase at 50°C. The effects of α-tocopherol and Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) on the oxidation of these TAG were also studied. Progress of oxidation was determined by measuring the oxygen consumption, peroxide formation, and polymer formation. The rates of oxygen consumption and polymer formation of bitter gourd-TAG and CLA-TAG were faster than those of perilla-TAG and soybean-TAG, respectively. The present results revealed that the main oxidation products of bitter gourd-TAG and CLA-TAG were dimers and polymers, whereas hydroperoxides were the main products in the oxidation of perilla-TAG and soybean-TAG. These differences in the oxidation of TAG were characterized mainly by oxidation of the main PUFA contained in each TAG, namely, linoleate (56.1%) for soybean-TAG, α-linolenate (54.5%) for perilla-TAG, conjugated linoleate (69.5%) for CLA-TAG, and conjugated linolenate (61.6%) for bitter gourd-TAG, respectively. α-Tocopherol and Trolox inhibited the oxidation of TAG. The inhibitory effect of these antioxidants was more effective against the oxidation of CLA-TAG and bitter gourd-TAG than that of soybean-TAG and perilla-TAG, respectively. This was probably due to the high rate at which the antioxidants inhibited the dimerization and polymerization of CLA-TAG and bitter gourd-TAG.     

N‐3 fatty acids and conjugated linoleic acids of longissimus muscle in beef cattle

The objective of the experiment with cattle was to produce high quality beef under different feeding conditions and to increase the concentration of essential fatty acids in muscle. In total 10 German Simmental (GS) bulls and 9 German Holstein (GH) steers were kept either on pasture (grass feeding) or in stable (concentrate feeding). Despite biohydrogenation in the rumen, linolenic acid (C18:3n‐3) contained in grass was absorbed and deposited into the lipids of muscle. This led to a significantly (p ≤ 0.05) higher content of n‐3 fatty acids in the muscle lipids of grazing cattle. The relative amount of total n‐3 fatty acids increased from 1.4 g/100 g fatty acid methyl ester (%FAME) in the intensively fed Simmental bulls to 5.5 %FAME in grass fed cattle. The n‐6/n‐3 ratio of pasture grazing GS bulls was 1.3 in contrast to 13.7 of the animals kept in the byre. The total n‐3 fatty acid concentration in beef muscle increased from 24.6 mg (concentrate) to 108.6 mg/100 g wet weight (grazing). In GH steers the total n‐3 fatty acid concentration was significantly (p ≤ 0.05) increased up to 86.3 mg/100 g wet weight in pasture grazing steers compared to 28.8 mg/100 g wet weight in animals fed the concentrate. The relative content (%FAME) of CLAcis‐9, trans‐11 (0.6 vs 0.56 %FAME in GS; 0.55 vs 0.52 %FAME in GH) in muscle was not significantly increased by grazing on pasture in comparison to concentrate feeding neither in GS bulls nor in GH steers, respectively.     

Lipid Composition and Antioxidant Capacity Evaluation in Tilapia Fillets Supplemented with a Blend of Oils and Vitamin E

Since the nutritional value of farm‐raised fish fillets is directly related to the diet provided, we supplemented the diet of Tilapia (Oreochromis niloticus) with a blend of chia (Salvia hispanica L.) oil, tung (Aleurites fordii) oil, and conjugated linoleic acid (CLA) to evaluate the effects on the fatty acid composition. Vitamin E was also added to the diet to improve the antioxidant capacity of tilapia fillets. We observed an increase in α‐linolenic acid content (from 6.56 to 19.03 mg g^?1 of total lipids), as well as the incorporation of CLA and conjugated linolenic acid (CLnA) isomers in the fillets. The addition of vitamin E resulted in the antioxidant capacity improvement of the fillets and higher values were found after 15 feeding days (39.25 µmol TE g^?1 in the Ferric Reducing Ability Power assay). Supplementation proved to be an excellent tool to improve the nutritional value of fish fillets.     

Adaptations of Skeletal Muscle Mitochondria to Obesity,Exercise, and Polyunsaturated Fatty Acids

Mitochondria intricately modulate their energy production through the control of mitochondrial adaptation (mitochondrial biogenesis, fusion, and/or fission) to meet energy demands. Nutrient overload may result in dysregulated mitochondrial biogenesis, morphology toward mitochondrial fragmentation, and oxidative stress in the skeletal muscle. In addition, physical activity and diet components influence mitochondrial function. Exercise may stimulate mitochondrial biogenesis and promote mitochondrial fusion/fission in the skeletal muscle. Moreover, some dietary fatty acids, such as n‐3 polyunsaturated fatty acids and conjugated linoleic acid, have been identified to positively regulate mitochondrial adaptation in the skeletal muscle. This review discusses the association of mitochondrial impairments and obesity, and presents an overview of various mechanisms of which exercise training and mitochondrial nutrients promote mitochondrial function in the skeletal muscle.     

Effects of probiotic bacteria and oils on fatty acid profiles of cultured cream

The aim of this study was to determine the effects of using various probiotic bacteria and plant oils in cultured cream on the fatty acid profiles including conjugated linoleic acids (CLA). L. acidophilus, B. bifidum, S. thermophilus and L. bulgaricus, P. thoenii (jensenii) P126, and P. jensenii B1264 and a mixed culture (blend of L. acidophilus, B. bifidum, S. thermophilus and L. bulgaricus) were used in the fermentation of cream samples at a level of 2%. Cream samples were fortified with sunflower oil, soybean oil and hazelnut oil at a level of 2%. Microbial counts and fatty acid profile analysis were performed. The microbial results demonstrated that fermented cream could be a superior product for the presence of probiotics. Even though the cream samples contained 52% milk fat, in the majority of the samples growth of probiotic bacteria was higher than 10⁶ cfu/g. Concentrations of short‐chain fatty acids such as butyric, caproic and capric acids in cultured cream samples differed depending on the cultures used, while long‐chain unsaturated fatty acids were significantly affected by the plant oil fortification. The highest CLA content was obtained in the sample produced with B. bifidum, containing 0.73 mg of CLA/g fat. The effect of different plant oils on CLA concentration was significant (p >0.05) for HO + YC, SFO + LBYC and SO + LBYC. Results of the study are important for the dairy industry since it is the first publication on fermented cream with improved functional properties. The development of functional cultured cream with plant oils and probiotic bacteria would provide an important alternative dairy product.     

月苋草油制备共轭亚油酸的研究

GC—MS分析月苋草油中脂肪酸的组成,其亚油酸含量很高。探讨制备和富集提纯亚油酸反应条件,研究在高压条件下金属催化剂对亚油酸共轭化的影响。     

Interplay between Humoral and CLA+ T Cell Response against Candida albicans in Psoriasis

Candida albicans (CA) infections have been associated with psoriasis onset or disease flares. However, the integrated immune response against this fungus is still poorly characterized in psoriasis. We studied specific immunoglobulins in plasma and the CA response in cocultures of circulating memory CD45RA⁻ cutaneous lymphocyte antigen (CLA)^+/− T cell with autologous epidermal cells from plaque and guttate psoriasis patients (cohort 1, n = 52), and also healthy individuals (n = 17). A complete proteomic profile was also evaluated in plaque psoriasis patients (cohort 2, n = 114) regarding their anti-CA IgA levels. Increased anti-CA IgA and IgG levels are present in the plasma from plaque but not guttate psoriasis compared to healthy controls. CA cellular response is confined to CLA⁺ T cells and is primarily Th17. The levels of anti-CA IgA are directly associated with CLA⁺ Th17 response in plaque psoriasis. Proteomic analysis revealed distinct profiles in psoriasis patients with high anti-CA IgA. C-C motif chemokine ligand 18, chitinase-3-like protein 1 and azurocidin were significantly elevated in the plasma from plaque psoriasis patients with high anti-CA levels and severe disease. Our results indicate a mechanism by which Candida albicans exposure can trigger a clinically relevant IL-17 response in psoriasis. Assessing anti-CA IgA levels may be useful in order to evaluate chronic psoriasis patients.     

用萃取体系负载有机相预分散水解法制备高比表面TiO2粉体

用三辛基氧化膦-煤油／盐酸-Ti（Ⅳ）萃取体系的负载有机相为内相制备了稳定的胶质液态泡沫（CLA）。用氨水水解油泡中的Ti（Ⅳ）制备了孔径约11nm,比表面约130m^2／g的TiO2粉体。用透射电镜（TEM）、氮气吸附和X射线衍射等方法对制得的材料进行了表征。     

Relative absorption of conjugated linoleic acid as triacylglycerol,free fatty acid and ethyl ester in a functional food matrix

Conjugated linoleic acid (CLA) shows potential benefits in a number of medical conditions, making it a possible target for incorporation into a functional food. Until recently, clinical trials were conducted with various mixtures of CLA isomers, encapsulated as the free acid. The purpose of this study was to examine a mixture of two specific CLA isomers (9c,11t and 10t,12c), incorporated into a functional food either as triacylglycerol, free fatty acid or fatty acid ethyl ester. Differences in absorption between the lipid forms and between the isomers were investigated. The palatability of the different functional‐food formulations was also studied. Significantly less CLA was absorbed into chylomicrons over six hours when fed as fatty acid ethyl ester than when either the triacylglycerol or free fatty acid forms were fed. Further work is recommended, to examine fatty acid ethyl ester absorption over longer periods of time. Most subjects reported that the fatty acid formulation had poor taste characteristics. We conclude that CLA as triacylglycerol is the most suitable form for incorporation into a functional food and that the 9c,11t and 10t,12c CLA isomers are absorbed similarly into chylomicrons.     

An improved molecular test system for the screening of human PPAR transactivation by conjugated linoleic acid isomers and their precursor fatty acids

To investigate the potentials of cis‐9,trans‐11 and trans‐10,cis‐12 conjugated linoleic acid (9‐CLA and 10‐CLA, respectively) isomers and their precursors trans‐11 vaccenic (VA), linoleic (LA) and oleic (OA) acids for interactions with genes, we determined their binding affinities to the ligand binding domains of the human peroxisome proliferator‐activated receptor (PPAR) α, β and γ subtypes by a fluorescent binding assay. Then, we elaborated a transactivation‐chemiluminescent assay using HepG2 cells transfected with full‐length cDNAs encoding human PPARs and retinoic acid (RA) receptors (RXRs) and with the ideal PPAR response element (iPPRE)‐luciferase reporter. Binding affinity of 9‐CLA was two times higher (but weaker than of precursor VA and OA) than that of 10‐CLA for PPARβ, the opposite was observed with PPARβ; binding affinities of CLAs and precursor fatty acids with PPARγ were comparable. Unlike in binding studies, transactivation potentials of 9‐ and 10‐CLAs were comparable in the human system. Comparing the transactivation potentials of CLAs and their precursors in toto, those obtained for PPARα (two‐ to fourfold) in both human and murine systems (the latter was used in this study as reference) were comparable, but for PPARβ and γ, fold inductions obtained in the human system were unique. Inclusion of the coactivator RXR and its natural ligand RA in the system was found unnecessary and would lead to false positive values. Taken together, the human transactivation‐based test system – which was found to be superior to the murine system – comprises only iPPRE and human PPARs for rapid screening of potential CLA and other PPAR agonists.     

硫酸氢钠催化合成共轭亚油酸的反应动力学

常压下,以蓖麻油为原料,硫酸氢钠为催化剂,对合成共轭亚油酸的反应动力学进行了研究,分析了搅拌速度、反应时间、催化剂的用量对反应转化率的影响。结果表明,蓖麻油酸异构化反应为一级反应,反应活化能为18.060 kJ/mol,动力学方程为r C=35.943 e-18.060/RT C A。     

Conjugated linoleic acids: Physiological effects in animal and man with special regard to body composition

Institute of Nutrition, Friedrich Schiller University of Jena, Jena, Germany In the last decade, conjugated linoleic acids (CLA) have been shown to have some beneficial (but also unfavourable) effects: anticarcinogenic properties, immune modulation, reduction of body fat and increase of lean body mass, normalisation of impaired glucose tolerance, promotion of fatty streak formation, and isomer‐specific effects. The research base on CLA has been derived almost exclusively from animal models, while some of the biological properties have been fairly well‐documented, others are still open to question. For about 5 years a lot of commercial CLA mixtures have been offered. These mixtures produced from linoleic acid‐rich oil like sunflower or safflower oil by alkali isomerization contained, besides cis‐9,trans‐11 and trans‐10,cis‐12 CLA isomers (about 20—40% of each), parts of cis,cis and trans,trans isomers as well. The quality of the recent products is significantly improved and they contain only two CLA isomers: cis‐9,trans‐11 and trans‐10,cis‐12. CLA play apparently a key role in regulating body composition. Several studies showed a reduction in body fat mass and a slight increase in lean body mass depending on the species. A possible explanation for the decrease of body fat may be a stimulation of lipolysis and a reduction of lipoprotein lipase activity in adipocytes. In adipose and muscle tissue a CLA‐stimulated increase of carnitine palmitoyltransferase activity resulting in an enhanced fatty acid oxidation was shown. There is evidence that CLA provide protection against cytokine‐induced (Tumour necrosis factor‐α, interleukin‐1) skeletal‐muscle catabolism (anabolic effect). The body composition modulating effects are most impressive in rodents and seem to become smaller in pigs and in humans. Data on humans are insufficient. Further research is essential to characterize the multifunctionality of CLA in humans, in order to identify the specific physiological mechanism of the biologically active isomers and to determine the optimal level of these isomers for beneficial effects.     

红花油制取共轭亚油酸的研究

以新疆克拉玛依厂的红花油为原料,以丙三醇为溶剂,在KOH的碱性催化作用下,将红花油先转化成亚油酸钾;再利用异构化反应制得浅黄色的共轭亚油酸产品。对产品进行了薄层层析法和紫外分光光度法定性分析,并定量分析了红花油异构化反应的程度。本研究对红花油的深加工将起到很好的推动作用。     

Conjugated Linoleic Acids and CLA-Containing Phospholipids Inhibit NO Formation in Aortic Endothelial Cells

This study examined the effects of five CLA isomers and the non-conjugated LA on nitric oxide (NO) production, an important modulator of vasodilation, inflammation, and cytotoxicity. Bovine aortic endothelial cells (BAECs) were pretreated with pure CLAs (c9, c11-, c9, t11-, t9, t11-, t10, c12-, c11, c13-CLA) and the non-conjugated c9, c12-analog, then stimulated by the ionophore A23187 followed by fluorescence monitoring of NO production. CLAs (5 μM) decreased NO formation in the range of 20–40% relative to non-fatty acid-treated controls with the t9, t11- and t10, c12-CLAs being the most effective. The inhibitory effect of either of these CLAs was not time dependent over a 120 min time interval. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) play crucial roles in membrane structure and cell signaling. Since CLAs are usually esterified in these phospholipids (PLs), the effects of three CLA-containing PLs and 2-linoleoyl-PC on NO production by A23187-stimulated BAECs were also examined. c9, t11-CLA-PC and 2-linoleoyl-PC dose-dependently inhibited NO production over a 60–1,000 μM concentration range whereas c9, c11-CLA-PC and c9, t11-CLA-PE were ineffective. Both c9, t11-CLA-PC and linoleoyl-PC exhibited a time-dependent decrease in NO production from 5 to 120 min. The results of the present study suggest that the influence of several C18 polyunsaturated fatty acids incorporated into cellular phospholipids on the A23187-induced formation of NO by BAECs is strongly dependent on the positional and geometric nature of the double bonds.