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。     

Selective Enrichment of Conjugated Linoleic Acid Isomers in Their Mixtures Using Combined Chemical and Enzymatic Methods

The aim of this study was to selectively enrich t10,c12-conjugated linoleic acid (t10,c12-CLA) and c9,t11-CLA in commercial CLA mixtures using a combination of urea crystallization and lipase-catalyzed esterification. The objective of the urea fractionation is to remove saturated and monounsaturated fatty acids (FA) from the CLA mixtures. CLA-enriched free FA (FFA) mixtures containing 53.8 wt% t10,c12-CLA and 39.1 wt% c9,t11-CLA were produced from the CLA mixtures containing ~34 wt% each of the two CLA isomers by a urea crystallization using methanol and the urea-to-FA weight ratio of 2.5:1. The CLA-enriched FFA mixtures were partially esterified with dodecan-1-ol in a recirculating packed-bed reactor using an immobilized lipase from Candida rugosa to further enrich the t10,c12-CLA and c9,t11-CLA in an FFA fraction and an FA dodecyl ester fraction, respectively, under the optimal conditions, i.e., temperature, 20 °C; FA-to-dodecan-1-ol molar ratio, 1:1; water content, 2 wt% of total substrates; residence time, 5 min; and reaction time, 24 h (for t10,c12-CLA enrichment) and 12 h (for c9,t11-CLA enrichment). After the reaction, an FFA fraction with 72.6 wt% t10,c12-CLA was obtained. Another FFA fraction with 62.0 wt% c9,t11-CLA was recovered after the saponification of the FA dodecyl ester fraction. The yields of t10,c12-CLA and c9,t11-CLA in the FFA fractions were 43.6 and 21.5 wt%, respectively, based on their initial weights in the CLA mixtures.     

Physicochemical Properties of Conjugated Linoleic Acid-Rich Soy Oil

CLA-rich soy oil (CLARSO) has been produced by linoleic acid isomerization in soy oil TAG. The objective was to determine the physicochemical properties of the novel CLARSO relative to conventional refined bleached deodorized soy oil (RBDSO). Iodine value decreased in CLARSO samples despite unsaturation being unchanged, probably because conjugated double bonds in triacylglycerol (TAG) of CLARSO impede the complete addition of iodine. Thermal analysis by differential scanning calorimetry showed the melting point temperature increased with the increase in the CLARSO CLA concentration, and melting point broadening occurred in CLA contained samples. Dynamic viscosity of CLARSO conducted from 4 to 44 °C increased with the increase in CLA concentration, relative to RBDSO. Greatest viscosity differences occurred at the lower temperatures. Refractive indices and density were not greatly affected. The change in physical properties was attributed to the increased intermolecular hydrophobic interaction force due to conjugated double bonds and trans,trans isomers, relative to RBDSO. This may provide hard fat characteristics that may be useful for use in producing margarine or shortenings. Furthermore, the higher viscosity at refrigerator temperatures may be useful in salad oil and refrigerated sauces to enable suspension of particles and maintain a rich, thicker texture.     

The Production of an Experimental Table Margarine Enriched with Conjugated Linoleic Acid (CLA): Physical Properties

Even though conjugated linoleic acid (CLA) is known to have some beneficial effects on the human body, its consumption has decreased over the past 20 years due to the replacement of animal fats by vegetable oils. In this study, using the structured lipid (SL) containing CLA, an experimental table margarine enriched with CLA was produced and stored for 3 months at two temperatures prior to performing the relevant analyses. The GC results showed that the margarine fat had 10.6% CLA. The solid fat content was the highest in week 0 in all samples, which then decreased during storage but the hardness increased. An increment in dropping point was also observed in the samples. In week 0, all the samples had the β′ crystal as the predominant crystal form but a crystal transformation from β′ to β was observed during storage.     

Production of Conjugated Linoleic Acid by Microwave-Assisted and Ultrasound-Assisted Alkali Isomerization: Effects of Microwave Power and Ultrasound Amplitude

Conjugated linoleic acid (CLA) is commercially produced by alkali isomerization of linoleic acid (LNA). However, this method constitutes a relatively high content of undesirable CLA isomers. In present study, microwave-assisted and ultrasound-assisted alkali isomerization techniques were applied for production of CLA as an alternative to traditional alkali isomerization. This study was aimed to evaluate the isomerization degree of LNA, by using various process conditions such as microwave power, ultrasound amplitude, and their reaction times. The best conditions for LNA isomerization were a microwave power of 700 W and a reaction time of 6 h for microwave-assisted alkali isomerization and an ultrasound amplitude of 100% and a reaction time of 6 h for ultrasound-assisted alkali isomerization. Under determined conditions, microwave-assisted alkali isomerization (97.21%) resulted in a higher isomerization degree compared to ultrasound-assisted alkali isomerization (76.98%) while the content of undesirable CLA isomers in ultrasound-assisted alkali isomerization (0.62%) was lower than that of microwave-assisted alkali isomerization (1.87%). This study showed that application of the both techniques resulted in equal amounts of desirable CLA isomers. The content of desirable CLA isomers was 47.09% cis-9, trans-11 and 48.25% trans-10, cis-12 for microwave-assisted alkali isomerization and 36.34% cis-9, trans-11 and 40.02% trans-10, cis-12 for ultrasound-assisted alkali isomerization.     

Effect of UV Processing Treatments on Soy Oil Conjugated Linoleic Acid Yields and Tocopherols Stability

Photoirradiation has been used to synthesize 20 % conjugated linoleic acid (CLA) in soy oil with an iodine catalyst. CLA yields are affected by ultraviolet (UV) irradiation time, Magnesol^® adsorbent treatment, iodine concentration and mixed tocopherols. However, these factors in combination had not been studied. Therefore, the objectives of this study were to determine the effect of (1) a combination of photoirradiation time, Magnesol^® adsorbent treatment and added mixed soy tocopherols on CLA yields and the oxidative stability of CLA-rich soy oil, (2) UV light on mixed tocopherol stability, as tocopherols enhance CLA yields during photoirradiation. Soy oil was initially treated with 5 % Magnesol^®. Iodine at 0 and 0.35 % was mixed with Magnesol^®-treated soy oil and irradiated for 12 and 6 h. The irradiated oil was again treated with Magnesol^®, mixed with 0, 0.35 or 0.175 % iodine; 1400 MT and irradiated for 12 or 6 more hours. CLA content in soy oil was determined by conventional gas chromatography-flame ionization detector. The oxidative stability of the oil was determined by measuring peroxide value (PV). The tocopherols stability was determined by high performance liquid chromatography. The results showed that increasing photoirradiation time increased CLA yields and lowered PV. Magnesol^® adsorption produced highest CLA yield for all treatments by removing peroxides in RBD soy oil. The γ-tocopherols exhibited highest stability during UV irradiation. The order of tocopherol degradation was α-tocopherol > δ-tocopherol > γ-tocopherols.     

Proteomic Analysis Reveals PGAM1 Altering cis‐9, trans‐11 Conjugated Linoleic Acid Synthesis in Bovine Mammary Gland

cis‐9, trans‐11 Conjugated linoleic acid (CLA) is one of the most extensively studied CLA isomers due to its multiple isomer‐specific effects. However, the molecular mechanisms of cis‐9,trans‐11 CLA synthesis in ruminant mammary gland are still not clearly understood. This process may be mediated, to a certain extent, by trans‐11 C18:1 regulated by stearoyl‐CoA desaturase‐1 (SCD1) and/or its syntrophic proteins. This study aimed to investigate the effects of TVA on SCD1‐mediated cis‐9,trans‐11 CLA synthesis in MAC‐T cells and its potential molecular mechanism. Results showed that trans‐11 C18:1 was continually taken up and converted into cis‐9,trans‐11 CLA in MAC‐T cells during the 4‐h incubation of 50 μM trans‐11 C18:1. SCD1 protein expression increased more than twofold at 2 h (P < 0.01) and 2.5 h (P < 0.05) before decreasing to less than half of the normal level at 4 h (P < 0.05). One up‐regulated (RAS guanyl releasing protein 4 isoform 1 [RASGRP4]) and six down‐regulated proteins (glucosamine‐6‐phosphate deaminase 1 [GNPDA1], triosephosphate isomerase [TPI1], phosphoglycerate mutase 1 [PGAM1], heat shock protein beta‐1 [HSPB1], annexin A3 [ANXA3], thiopurine S‐methyltransferase [TPMT]) were found in MAC‐T cells treated with trans‐11 C18:1. Of these seven identified proteins, the presence of GNPDA1 and PGAM1 was verified in several models. More trans‐11 C18:1 was taken up after PGAM1 knockdown by small interfering RNA (siRNA). In conclusion, our data suggested that PGAM1 may have a negative relationship with SCD1 and seemed to be involved in cis‐9, trans‐11 CLA synthesis by facilitating the absorption of trans‐11 C18:1 in the bovine mammary gland.     

Dietary Conjugated Linoleic Acid-c9t11 Prevents Collagen-Induced Arthritis,Whereas Conjugated Linoleic Acid-t10c12 Increases Arthritic Severity

Two conjugated linoleic acid (CLA) isomers, cis‐9, trans‐11 (CLAc9t11) and trans‐10, cis‐12 (CLAt10c12), reduce inflammation in a number of animal models, including collagen‐induced arthritis (CA). However, little is known about the ability of individual CLA isomers to prevent autoimmune disease onset. Evidence that mixed isomer CLA drives T helper cell (Th) 1 responses suggests that CLA, or a specific isomer, exacerbates onset of Th1 autoimmune diseases. In two experiments, we examined if prior dietary exposure to CLAt10c12 (experiment 1) or CLAc9t11 (experiment 2) affected the incidence or severity of CA. DBA/1 mice were fed a semi purified diet with either 6% corn oil (CO, w/w), 5.75% CO plus 0.25% CLAt10c12, or 5.5% CO plus 0.5% CLAc9t11 prior to arthritis development. Arthritis incidence and severity, anti‐collagen antibodies, paw cytokines, and hepatic fatty acids were measured. CLAt10c12 had no effect on arthritis incidence but increased arthritic severity (42%, P = 0.02); however, CLAc9t11 decreased arthritis incidence 39% compared to CO fed mice (P = 0.01), but had no effect on disease severity. CLAt10c12‐induced increase in anti‐collagen type II IgG antibodies may be a mechanism by which this isomer increased arthritic severity, and CLAc9t11‐induced increase in Th2 paw cytokines (IL‐4 and IL‐10, P ≤ 0.04) may explain how CLAc9t11 reduced the arthritis incidence. While both isomers are well known to reduce inflammation in arthritic mice, these new data suggest isomer differences when fed prior to autoimmune disease.     

Responses of MAC‐T Cells to Inhibited Stearoyl‐CoA Desaturase 1 during cis‐9, trans‐11 Conjugated Linoleic Acid Synthesis

Cis‐9‐conjugated, trans‐11‐conjugated linoleic acid (CLA) is known for its positive activities on human health. The synthesis of cis‐9, trans‐11 CLA in mammary glands is generally thought to be catalyzed by stearoyl‐CoA desaturase 1 (SCD1), but this has not been rigorously established. In this study, we hypothesized that the inhibition of SCD1 (by CAY10566) would block the synthesis of cis‐9, trans‐11 CLA in bovine mammary alveolar cells (MAC‐T) cells. Results showed that MAC‐T cells incubated with 10 nM CAY10566 for 12 h (CAY) produced less cis‐9, trans‐11 CLA (p < 0.01), lower 14:1/(14:1 + 14:0)% (p < 0.01), more trans‐11 18:1 (TVA) accumulation (p < 0.01), and reduced SCD1 mRNA levels (p < 0.01) compared with the control group (CON). Moreover, the mRNA abundances of sterol regulatory element‐binding protein 1 [SREBPF1], acyl‐CoA synthetase short‐chain family member 2 [ACSS2], and lipin 1 [LPIN1] were significantly elevated when SCD1 was inhibited in the CAY group (p < 0.05). Taken together, CAY10566 inhibition of SCD1 resulted in lower cis‐9, trans‐11 CLA synthesis ability, and SREBF1, ACSSS2, and LPIN1 were negatively associated with SCD1. These findings not only provide the direct evidence that cis‐9, trans‐11 CLA synthesis is catalyzed by SCD1, but also help us understand the responses of MAC‐T cells to SCD1 inhibition.     

Oxidative Stability of Conjugated Linoleic Acid Rich Soy Oil Obtained by Heterogeneous Catalysis

A CLA rich‐soy oil (CLARSO) has been produced by heterogenous catalysis. This oil may provide significant health benefits. The objectives of this study were: to determine the oxidative stability of the CLARSO and CLARSO after adsorption treatment [ 1 ], relative to conventional soy oil, in terms of primary and secondary oxidation products and to determine CLA and other unsaturated fatty acids oxidation kinetics in the CLARSO [ 2 ]. Primary and secondary oxidation products were measured in CLARSO and soy oil samples kept at 50 °C in the dark. The CLARSO was less stable than soy oil but bleaching improved its oxidative stability. The induction times were dependent on the analytical method used. Fatty acid oxidation kinetics was determined by measuring each fatty acid and hydroperoxides in CLARSO at 52, 61 and 69 °C in the dark. Unsaturated fatty acids oxidation rate constants, activation energies and frequency factors were obtained by the Arrhenius equation. Kinetics studies showed that CLA isomers had higher rate constants, higher activation energies and higher frequency factors than linoleic acid which showed that the CLA isomers had more molecular collisions with oxygen than linoleic acid.     

Conjugated Linoleic Acid Decreases MCF-7 Human Breast Cancer Cell Growth and Insulin-Like Growth Factor-1 Receptor Levels

In vitro work suggests that conjugated linoleic acid (CLA) isomers (c9,t11 and t10,c12) are cytotoxic to human breast cancer cells, however the mechanism remains unknown. Using human MCF-7 breast cancer cells, we examined the effects of c9,t11 and t10,c12 CLA compared to oleic acid (OA), linoleic acid (LA), or untreated cells on cell membrane phospholipid composition, cell survival, and the insulin-like growth factor-I (IGF-I) and the downstream insulin receptor substrate-1 (IRS-1). Both CLA isomers were incorporated into membrane phospholipids (p < 0.05). Compared to untreated cells, c9,t11 or t10,c12 CLA significantly reduced the metabolic activity of IGF-I stimulated MCF-7 cells, increased lactate dehydrogenase (LDH) release, and decreased cellular concentrations of the IGF-I receptor (IGF-IR) and insulin receptor substrate-1 (p < 0.05). Incubation with t10,c12 CLA also reduced the levels of phosphorylated IGF-1R. The effects on all of these measures were greater (p < 0.05) for t10,c12 CLA compared to c9,t11 CLA. There were few differences between LA-treated and c9,t11 CLA-treated cells, whereas cellular metabolic activity, LDH release, and IGF-IR concentrations differed between t10,c12 CLA-treated and LA-treated cells (p < 0.05). OA stimulated growth compared to the untreated condition (p < 0.05). In summary, this study demonstrated that the t10,c12 CLA isomer inhibits growth of MCF-7 cells and suggested that this may be mediated through incorporation into cellular phospholipids and interference with the function of IGF-I and related signaling proteins.     

Investigation of Micellization and Vesiculation of Conjugated Linoleic Acid by Means of Self‐Assembling and Self‐Crosslinking

Bioactive and biocompatible conjugated linoleic acid (CLA) has been only considered as a food or medicine ingredient due to its rare natural occurrence. In this work, the surface activities and pH‐induced self‐assembling behaviors of the semi‐synthetic CLA molecules into micelles or vesicles were systematically investigated. First, the self‐assembling of CLA was studied in detail, and it was found that aside from temperature and ionic strength, pH is the prominent factor affecting the self‐assembling of CLA. Moreover, stable CLA ufasomes (unsaturated fatty acid liposomes) in uniform size were obtained by self‐crosslinking of the CLA ufasomes, and the morphologies of the crosslinked CLA assemblies were recorded by transmission electron microscopy, which made known the pH‐induced formation of the CLA ufasomes or the CLA micelles. The crosslinked CLA assemblies presented improved properties such as a higher calcium stability, a lower lime soap dispersing requirement and a better solubilization ability than that of the CLA molecules themselves or the pre‐crosslinked linoleic acids. These investigations could be helpful for comprehensively understanding effects of environment factors on self‐assembling behaviors of conjugated fatty acids and responsive polymerization of polymerizable surfactants.     

A simple method of preparation of methyl trans-10,cis-12- and cis-9,trans-11-octadecadienoates from methyl linoleate

Pure conjugated isomers of linoleic acid were prepared on a large scale by alkali-isomerization of purified methyl linoleate. The methyl esters of alkali-isomerized linoleic acid contained mainly the methyl cis-9,trans-11- and trans-10,cis-12-octadecadienoates (44 and 47%, respectively). These two isomers were then separated and purified by a series of low-temperature crystallizations from acetone. The isomeric purity obtained for the cis-9,trans-11-octadecadienoate isomer was >90% and that of the trans-10,cis-12-octadecadienoate isomer was 89 to 97%. The isolated yield of the two isomers corresponded to 18 and 25.7%, respectively, of the starting material. The structure of the two isomers was confirmed using partial hydrazine reduction, silver nitrate-thin-layer chromatography of the resulting monoenes and gas chromatography coupled with mass spectrometry of the 4,4-dimethyloxazoline derivatives. Fourier transform infrared spectroscopy of the monoenes gave the confirmation of the geometry of each double bond.     

高效液相色谱法测定含 DIANP 的发射药组分

采用高效液相色谱法测定含１，５－二叠氮基－３－硝基－３－氮杂戊烷的发射药组分。使用烷基柱及乙腈－甲醇－水或甲醇－水混合流动相，可测定ＤＩＡＮＰ、黑索今、硝化甘油、二硝基甲苯和中定剂。     

A Comparison of the Anti-Inflammatory Effects of <Emphasis Type="Italic">Cis</Emphasis>-9, <Emphasis Type="Italic">Trans</Emphasis>-11 Conjugated Linoleic Acid to Celecoxib in the Collagen-Induced Arthritis Model

Cyclooxygenase (COX)‐2 inhibitors, such as celecoxib, for chronic inflammatory disease are associated with adverse health events, while cis‐9, trans‐11 (c9t11) conjugated linoleic acid (CLA) is anti‐inflammatory without adverse events attributed to pure intake. Mechanistically, celecoxib and c9t11 disrupt the arachidonic acid cascade; however, the equivalency of anti‐inflammatory effects between these compounds is unknown. Therefore, to test the hypothesis that 0.5% dietary c9t11 reduces inflammation equivalently to a celecoxib dose intended to treat rheumatoid arthritis (RA; 5 mg/kg bw), arthritic mice received diets containing one of the following supplements: 1% corn oil (CO, w/w), 0.5% c9t11 (>91% purity) +0.5% CO, or 1% CO + 0.5, 5, or 50 mg/kg bw celecoxib, and were assessed for changes in arthritic severity over 6 weeks. Overall, arthritic severity in mice fed c9t11 was reduced (34%, P < 0.01) while celecoxib doses (0.5, 5, 50 mg/kg) reduced arthritic severity (16, 56, 48%, respectively) compared to CO‐fed arthritic mice. Linear regression of the celecoxib dose‐response showed 0.5% c9t11 (570 mg/kg bw) reduced arthritic severity equivalently to 1.5 mg/kg celecoxib. Interleukin‐6 (IL‐6) was increased in paws of arthritic mice fed CO compared to shams, but was decreased in arthritic groups fed 0.5% c9t11 and 5 mg/kg celecoxib, compared to arthritic mice fed CO (Ps ≤ 0.05). Additionally, paw and plasma IL‐10 levels in arthritic mice were decreased by 5 mg/kg celecoxib, but were unaffected by c9t11 compared to CO. Results suggest dietary c9t11 may be an effective adjunct to COX‐2 inhibition for treating chronic inflammation.     

Determination of low level trans unsaturation in physically refined vegetable oils by capillary GLC — Results of 3 intercomparison studies

The analytical performance of capillary gas‐liquid chromatographic (GLC) methods for the quantitative determination of trans fatty acids (TFA) in physically refined rapeseed and soybean oils was evaluated by 3 intercomparison studies. The participants were allowed to use their own methodology regarding derivatization and GLC conditions and were not requested to follow a fixed method protocol. However, certain requirements relating to the separation efficiency (chromatographic separation of critical pairs) and the accuracy (validation of the response factors using a certified reference material) of the method(s) applied, had to be fulfilled. All 12 participating laboratories employed fused silica capillary columns coated with cyanopropyl polysiloxane for the separation of fatty acid methyl esters. Analytical precision was sufficient (relative standard deviation for reproducibility 13%) for the quantification of trans isomers occurring at levels >0.1 g/100 g in physically refined vegetable oils, i.e. trans isomers of linolenic acid. For TFA levels <0.1 g/100 g (trans isomers of oleic and linoleic acid) precision dropped sharply (relative standard deviation for reproducibility >30%).     

Directed sequential synthesis of conjugated linoleic acid isomers from Δ7, 9 to Δ12, 14

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‐C_n, trans‐C_n+2 double bond system was rearranged through a pericyclic [1, 5] sigmatropic mechanism into a trans‐C_n‐1, cis‐C_n+1 unsaturated system, while the trans‐C_n, cis‐C_n+2 double bond system was rearranged through a similar pericyclic mechanism into a cis‐C_n+1, trans‐C_n+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.     

Separation and Quantification of Vegetable Oil Based Polyols by High Performance Liquid Chromatography with Evaporative Light Scattering Detection

Polyols with terminal primary alcohol functionalities were obtained from canola oil via an ozonolysis and hydrogenation process. A high performance liquid chromatography (HPLC) method with evaporative light scattering detection (ELSD) was developed for separating and quantifying the polyol products. Linear calibration curves were obtained for the mono-ol, diol and triol components with correlations (r ²) above 0.98. According to the standard curve, the content of mono-ol, diol and triol can be obtained from their HPLC-ELSD chromatograms.