Influence of C18 long chain fatty acids on butyrate degradation by a mixed culture

Butyrate degradation in the presence of C₁₈ long chain fatty acids (LCFAs) was examined under anaerobic conditions at 21 °C. Butyrate degradation rates were a function of linoleic acid (LA) and oleic acid (OA) concentration but independent of the amount of stearic acid (SA) added. Within 2–4 h, butyrate reached undetectable levels in the control cultures. However, in cultures fed with LA, butyrate was removed within between 12 and 25 h and within 2–12 h for cultures inoculated with OA or SA. Propionate was detected in cultures fed with 50 mg dm^?3 LA and in cultures inoculated with OA and SA. LA exerted a greater inhibitory effect on butyrate‐degrading organisms than OA and SA with longer removal times observed in cultures fed with LA. The propionate and acetate removal times and quantity produced were not related to the type and concentration of LCFA. Copyright © 2004 Society of Chemical Industry     

Glucose fermentation in the presence of linoleic,oleic and stearic acids by a mixed culture

Long Chain Fatty Acid (LCFA) mixtures containing linoleic, oleic and stearic acids plus carbohydrates are found in a variety of effluents arising from fried food manufacture and milk processing. Accumulation of Volatile Fatty acids (VFAs) due to the presence of LCFAs may impair the operation of an anaerobic system treating effluents containing a mixture of triglycerides and carbohydrates. In this study, the effects of linoleic (C18:2), oleic (C18:1), and stearic (C18:0) acids on glucose fermentation were investigated at 21 °C using a culture acclimated to glucose. In cultures receiving ≥300 mg dm^?3 LCFAs, residual amounts of glucose remained after approximately 8 h and none was detected after 24 h. Acetate degradation was inhibited in the presence of 300 or more mg dm^?3 linoleic acid (LA), oleic acid (OA), or stearic acid (SA) with more acetate accumulation observed in cultures receiving LA. In comparison to the controls, similar amounts of propionate accumulation were observed in cultures receiving ≤100 mg dm^?3 of each LCFA. However, in cultures receiving ≥300 mg dm^?3 LCFAs, more propionate accumulated with complete removal observed within 20 days for only those cultures receiving oleic or stearic acids. Butyrate accumulation was observed only in cultures receiving ≥300 mg dm^?3 LA and none was detected after 10 days of incubation. Copyright © 2004 Society of Chemical Industry     

C16、C18混合脂肪酸分离技术研究进展

C16、C18混合脂肪酸中含有很多经济价值很高的组分,若能将这些组分分离出来加以利用,将极大地提高混合脂肪酸的利用价值,因此研究C16、C18混合脂肪酸的分离技术具有非常重要的意义。本文介绍了减压精馏、低温结晶、尿素包合、银离子络合、生物酶催化法等C16、C18混合脂肪酸分离方法在近十年来的研究进展,并分析了各种分离方法的优缺点和适用范围。减压精馏可以有效地将混合脂肪酸分离成C16组分与C18组分,但该法的主要问题是加热易使不饱和组分变质。尿素包合法最常用来分离C16、C18混合脂肪酸中的饱和组分与不饱和组分,目前对该法的研究主要集中在工艺条件的优化与改善。生物酶催化法选择性高、反应条件温和、绿色环保,目前已被用来分离α-亚麻酸以及γ-亚麻酸且效果良好。最后展望了C16、C18混合脂肪酸分离技术的发展前景,指出两种或多种分离方法组合以及生物酶催化法将是未来的发展趋势。     

Proportions of C18∶1n−7 and C18∶1n−9 fatty acids in canola seedcoat surface and internal lipids

Lipids of canola seedcoats (Brassica napus L. andB. rapa L.) were prepared by surface washing and by complete extraction of seed coats with toluene. The major fatty acyl-containing triacylglycerols, wax esters and free fatty acids were separated by thin-layer chromatography prior to transesterification and analysis by gas-liquid chromatography. The proportion of C18∶1n−7 to C18∶1n−9 was higher in the extracted lipids than in the surface-washed lipids for all three classes.     

Diffusion coefficients of C18 unsaturated fatty acid methyl esters in supercritical carbon dioxide containing 10% mole fraction ethanol as modifier

To determine the molecular diffusion coefficients of C18 unsaturated fatty acid methyl esters in supercritical carbon dioxide (scCO₂) containing 10 mol% ethanol as a modifier, four methyl esters of C18 fatty acids, i.e., methyl oleate, methyl ricinoleate, methyl linoleate and methyl linolenate were selected as the typical solutes. The diffusion coefficients were measured at temperatures from 313.15 to 333.15 K and pressures from 15 to 27 MPa using the Taylor–Aris chromatographic peak broadening (CPB) technique. The influences of temperature, pressure, density and viscosity of the solvent mixture on the diffusion coefficients were examined. The results show that methyl oleate always diffuses faster than methyl ricinoleate at the same operating condition. Moreover, the D₁₂ values in ethanol-modified scCO₂ decrease with the increase of the number of C-C double bonds in C18-methyl ester, which is consistent with the trend reported in pure scCO₂. The diffusivity data are compared with the estimation of eleven predictive models. The modified Wilke–Chang equation is the best purely predictive model and the free volume model of Dymond with two adjustable parameter gives the least errors with average absolute deviations lower than 2.5%.     

Clinical application of C18 and C20 chain length polyunsaturated fatty acids and their biotechnological production in plants

A potential revolution in FA therapies is on the horizon. In recent years, the full magnitude of various FA treatments and their overall importance to health has become increasingly apparent. Fetal and infant nutrition studies have clearly shown that FA status at birth can have life-long health implications affecting eye and brain function, insulin resistance, and blood pressure control. As well, nutrition studies have identified dietary imbalances and deficiencies that have the potential to alter the health of future generations severely and to promote progression of age-related degenerative disorders. Mixtures of naturally occurring FA have shown promise as therapeutic agents for a diverse range of health conditions including atopic eczema, rheumatoid arthritis, cardiovascular disease, and neurological problems. Through the 1990s, the creation of technologies to concentrate and formulate pharmacologically active individual FA components as well as tailored combinations propelled development of this new drug category. However, high production costs and government regulatory encumbrance limited the expansion of this emerging pharmaceutical sector. Fortunately, many countries are now creating regulatory frameworks that are better suited for product evaluation and control of the manufacturing FA products than historical drug models, and hence expansion in this area is now anticipated.     

Electron impact mass spectra of the oxazoline derivatives of some conjugated diene and triene C18 fatty acids

The location of the double-bond systems of some conjugated diene and triene C₁₈ fatty acids (C18∶2[9,11], C18∶2[10,12], C18∶3[9,11,13] and C18∶3[10,12,14]) derived from alkaline isomerization has been determined by gas chromatography/mass spectroscopy analysis of their 4,4-dimethyloxazoline derivatives. The positions of the double bonds were indicated by a characteristic mass separation of 12 atomic mass units for each olefinic bond. Furthermore, the structure assignments were supported by the presence of prominent formal allylic cleavage peaks.     

Acidogenic fermentation of blended food‐waste in combination with primary sludge for the production of volatile fatty acids

The performance of a laboratory‐scale anaerobic acidogenic fermenter fed with a mixture of blended kitchen food‐waste and primary sludge from a sewage treatment plant was investigated for the production of volatile fatty acids (VFA). The operating variables for acidogenic fermentation were kitchen food‐waste content (10 and 25 wt %), hydraulic retention time (HRT: 1, 3 and 5 days), temperature (ambient: 18 ± 2 °C, and mesophilic: 35 ± 2 °C) and pH (varied from 5.2 to 6.7). The experimental results indicated that effluent VFA concentrations and VFA production rates were higher at ambient temperature than at mesophilic conditions. The net amount of VFA with 10 wt % food‐waste increased up to 920 mg dm^?3 with an increase of HRT, but contrasting results (a decrease of 2610 mg dm^?3) were found due to the conversion of VFA into biogas in the case of 25 wt % food‐waste, which increased significantly at HRT of 3–5 days. In terms of biogas composition (CO₂ and CH₄), the organic matter was converted into CO₂ through the oxidative pathway by facultative species at low temperature while mesophilic temperature and optimum pH (6.3–7.8) played a pivotal role in increasing rate of conversion of VFA into biogas by methanogenesis. Rates of VFA production and their conversion are dependent on the food‐waste content in the mixture. Yet, the higher concentration of food‐waste (25% compared with 10%) did not produce VFA proportionally due to the increased rate of conversion of VFA into gaseous products. The maximum VFA production rate (0.318 g VFA_produced g^?1 VS_fed day^?1) was achieved in the 10 wt % food‐waste at ambient temperature and at a 5‐day HRT. Copyright © 2005 Society of Chemical Industry     

Cyclic fatty acids in sunflower oils during frying of frozen foods with oil replenishment

Frying of frozen foods has become popular because it considerably reduces cooking time. Polymers and cyclic fatty acid monomers (CFAM) formed during frying are potentially toxic and therefore their production should be minimized. Twenty discontinuous fryings of different frozen foods were carried out over ten consecutive days, in sunflower oil (SO) and in high‐oleic acid sunflower oil (HOSO), by adding fresh oil after each frying to bring the volume of the fryer oil back to 3 L. CFAM methyl ester derivates were hydrogenated, isolated, concentrated and quantified by HPLC using a reverse‐phase column, followed by gas chromatography. After 20 fryings, significantly higher contents of polar material, polymers and CFAM (all p <0.001) were found in SO than in HOSO. Bicyclic compound formation was four times higher in SO (p <0.001). The fat from the fried potatoes presented a polymer content very similar to that of their corresponding oils. The 100‐g rations of the SO‐fried potatoes from the 20^th frying supply 49 or 15%, respectively, more polymers and CFAM and 1 mg more bicyclic fatty acids than the 100‐g rations of HOSO‐fried potatoes. Because digestion and absorption of polar material, polymers and CFAM occur, the data clearly show the advantageousness and advisability of frying with HOSO rather than SO.     

Impact of a Standard Rodent Chow Diet on Tissue n‐6 Fatty Acids, Δ9‐Desaturation Index,and Plasmalogen Mass in Rats Fed for One Year

Although many studies focus on senescence mechanisms, few habitually consider age as a biological parameter. Considering the effect of interactions between food and age on metabolism, here we depict the lipid framework of 12 tissues isolated from Sprague–Dawley rats fed standard rodent chow over 1 year, an age below which animals are commonly studied. The aim is to define relevant markers of lipid metabolism influenced by age in performing a fatty acid (FA) and dimethylacetal profile from total lipids. First, our results confirm impregnation of adipose and muscular tissues with medium‐chain FA derived from maternal milk during early infancy. Secondly, when animals were switched to standard croquettes, tissues were remarkably enriched in n‐6 FA and especially 18:2n‐6. This impregnation over time was coupled with a decrease of the desaturation index and correlated with lower activities of hepatic Δ5‐ and Δ6‐desaturases. In parallel, we emphasize the singular status of testis, where 22:5n‐6, 24:4n‐6, and 24:5n‐6 were exceptionally accumulated with growth. Thirdly, 18:1n‐7, usually found as a discrete FA, greatly accrued over the course of time, mostly in liver and coupled with Δ9‐desaturase expression. Fourthly, skeletal muscle was characterized by a surprising enrichment of 22:6n‐3 in adults, which tended to decline in older rats. Finally, plasmalogen‐derived dimethylacetals were specifically abundant in brain, erythrocytes, lung, and heart. Most notably, a shift in the fatty aldehyde moiety was observed, especially in brain and erythrocytes, implying that red blood cell analysis could be a good indicator of brain plasmalogens.     

Genome-Wide Identification and Expression Analysis of Fatty Acid Desaturase (FAD) Genes in Camelina sativa (L.) Crantz

Camelina sativa (L.) Crantz is an indispensable oilseed crop, and its seeds contain many unsaturated fatty acids. FAD (fatty acid desaturase) regulates the synthesis of unsaturated fatty acids. In this research, we performed CsFAD gene family analysis and identified 24 CsFAD genes in Camelina, which were unevenly distributed on 14 of the 19 total chromosomes. Phylogenetic analysis showed that CsFAD includes four subfamilies, supported by the conserved structures and motifs of CsFAD genes. In addition, we investigated the expression patterns of the FAD family in the different tissues of Camelina. We found that CsFAD family genes were all expressed in the stem, and CsFAD2-2 was highly expressed in the early stage of seed development. Moreover, during low temperature (4 °C) stress, we identified that the expression level of CsFAD2-2 significantly changed. By observing the transient expression of CsFAD2-2 in Arabidopsis protoplasts, we found that CsFAD2-2 was located on the nucleus. Through the detection and analysis of fatty acids, we prove that CsFAD2-2 is involved in the synthesis of linolenic acid (C18:3). In conclusion, we identified CsFAD2-2 through the phylogenetic analysis of the CsFAD gene family and further determined the fatty acid content to find that CsFAD2-2 is involved in fatty acid synthesis in Camelina.     

Study on kinetics of polymerization of dimer fatty acids with ethylenediamine in the presence of catalyst

A generally applicable stoichiometric and kinetic model was developed for the polymerization of dimer fatty acids with ethylenediamine in the presence of phosphoric acid as catalyst. Rate equation used is based on second order and the temperatures are between 405 and 475 K with mixing rate of 75 rpm. The parameters of the rate equations are determined using nonlinear regression analysis. Comparison of the model predictions with the experimental data show that the approach is useful in predicting the polymerization kinetic. Equilibrium constant changes from 2.432 to 17.765. Frequency factor and activation energy for forward rate constant are 362306102.681 kg mol⁻¹ min⁻¹ and 83.24 kJ mol⁻¹, respectively. The equilibrium constant is independent of temperature with frequency factor and activation energy values of 17317.97 and 28.65 kJ mol⁻¹, respectively.     

Effects of frying on the trans‐fatty acid formation in soybean oils

To evaluate the effects of repeated deep‐frying on the trans‐fatty acid (TFA) formation in soybean oils, simultaneous frying experiments were carried out. French fries were prepared using three different types of soybean oil (pressed soybean oil, PSBO; first‐grade solvent extracted soybean oil, FG‐SESBO; and third‐grade solvent extracted soybean oil, TG‐SESBO). French fries were fried intermittently at 180–185°C for a total frying time of 32 h and at an interval time of 30 min. It was found that the initial amount of total TFAs was 0.29 g/100 g, 0.31 g/100 g, and 0.90 g/100 g in PSBO, TG‐SESBO, and FG‐SESBO, respectively. Before the frying started, the C18:1,t‐9, trans‐linoleic acid (TLA), trans‐linolenic acid (TLNA), and total TFA content of the PSBO and TG‐SESBO were significantly lower than in the FG‐SESBO (p<0.05). However, in the frying oil samples, the final concentration of total TFA in the PSBO, TG‐SESBO, and FG‐SESBO were 1.79 ± 0.17 g/100 g, 1.12 ± 0.10 g/100 g, and 1.70 ± 0.07 g/100 g, which was 6.17‐, 3.61‐, and 1.89‐fold higher that in fresh oil, respectively. The highest increasing slopes of C18:1,t‐9, TLA, TLNA, and total TFA were observed in the PSBO. Practical applications : A high intake of TFAs has been shown to lead to an increased risk of coronary heart disease. Plant oils, particularly soybean oil, have been widely used in the food industry in China. Frying is one of the most common methods to cook food. The formation of TFAs during frying has been shown to be closely related to the temperature and duration of the frying process. However, the effects of frying on the formation of TFAs in different soybean oils have not been well studied. In the present study, we demonstrated that increasing the number of frying cycles can cause an intensive increase in the concentration of TFAs in different types of soybean oil, but especially in PSBO.     

Trans fatty acids influence the oxidation of LDL in ECV304 cells

The objectives of this study are to explore whether separate sources of trans fatty acids (TFA) have different effects on ECV304 cell line and to further elucidate the oxidation mechanism induced by TFA. ECV304 cells are used in the study because they display many endothelial features. Cell apoptosis rates increased in a dose‐dependent manner following 24‐h treatment with TFA from separate sources. Additionally, TFA stimulated human alpha‐defensin 1 (HNP‐1) expression and resulted in a significant increase in both malondialdehyde (MDA) and ROS levels. MDA levels reach their peak at 18 h. HNP‐1 expression levels increase at 2 h and then reach their peak at 10 h. At the same time, the protein carbonyl (PCO) value declines slightly. After 10 h of TFA co‐culture, the cells were washed and fresh low‐density lipoprotein (LDL) was added. MDA generation significantly increased after 6 h and it could be inhibited by 4‐aminobenzoic acid hydrazide (ABAH) or sodium ferulate. However, after the TFA co‐culture for 2 h, adding LDL for 6 h just caused slight MDA generation change and the MDA generation could be inhibited by verapamil or sodium ferulate. TFA from different sources did not have different effects on ECV304. HNP‐1 mediates the oxidation induced by TFA by activating ROS. Furthermore, TFA can stimulate the oxidation of LDL in ECV304 cells through both passive and active pathway. In the oxidation induced by linoelaidic acid, ABAH can decrease the MDA generation in active oxidation pathway and verapamil can decrease the MDA generation in passive oxidation pathway.     

Comparing Subcutaneous Adipose Tissue in Beef and Muskox with Emphasis on <Emphasis Type="Italic">trans</Emphasis> 18:1 and Conjugated Linoleic Acids

Muskox (Ovibos moschatus) are ruminant animals native to the far north and little is known about their fatty acid composition. Subcutaneous adipose tissue (backfat) from 16 wild muskox was analyzed and compared to backfat from 16 barley fed beef cattle. Muskox backfat composition differed substantially from beef and the most striking difference was a high content of 18:0 (26.8 vs. 9.77%). This was accompanied by higher levels of most other saturated fatty acids except beef had more 16:0. Muskox backfat also had a lower level of cis-18:1 and this was related to a lower expression of steroyl-CoA desaturase mRNA. Beef backfat had a higher level of total trans-18:1 (4.25 vs. 2.67%). The most prominent trans-18:1 isomers in beef backfat were 10t-18:1 (2.13%) and 11t-18:1 (0.77%) whereas the most prominent isomers in muskox backfat were 11t-18:1 (1.41%), 13t/14t- (0.27%) and 16t-18:1 (0.23%). The total conjugated linoleic acid (CLA) content was higher in beef backfat than muskox (0.67 vs. 0.50%) with 9c,11t-18:2 as the most abundant CLA isomer. The second most abundant CLA isomer in beef backfat was 7t,9c-18:2 (0.10%) whereas in muskox it was 11t13c-18:2 (0.04%). Muskox backfat had a higher content of 18:3n-3 and its elongation and desaturation products 20:5n-3, 22:5n-3 and 22:6n-3 and a lower n-6/n-3 ratio. Overall, the high forage diet of muskox seemed to produce a healthier fatty acid profile and highlighted the need to develop feeding strategies for intensively raising beef that will not negatively impacting fatty acid composition.     

Analysis of saturated free fatty acids from pollen by HPLC with fluorescence detection

A sensitive method for the determination of free fatty acids using 2‐(2‐(anthracen‐10‐yl)‐1H‐naphtho[2,3‐d]imidazol‐1‐yl) ethyl‐p‐toluenesulfonate (ANITS) as tagging reagent with fluorescence detection has been developed. ANITS could easily and quickly label fatty acids in the presence of the K₂CO₃ catalyst at 90 °C for 40 min in N,N‐dimethylformamide solvent. From the extracts of rape bee pollen samples, 20 free fatty acids were sensitively determined. Fatty acid derivatives were separated on a reversed‐phase Eclipse XDB‐C₈ column by HPLC in conjunction with gradient elution. The corresponding derivatives were identified by post‐column APCI/MS in positive‐ion detection mode. ANITS‐fatty acid derivatives gave an intense molecular ion peak at m/z [M+H]⁺; with MS/MS analysis, the collision‐induced dissociation spectra of m/z [M+H]⁺ produced the specific fragment ions at m/z [M–345]⁺ and m/z 345.0 (here, m/z 345 is the core structural moiety of the ANITS molecule). The fluorescence excitation and emission wavelengths of the derivatives were λ_ex = 250 nm and λ_em = 512 nm, respectively. Linear correlation coefficients for all fatty acid derivatives are >0.9999. Detection limits, at a signal‐to‐noise ratio of 3 : 1, are 24.76–98.79 fmol for the labeled fatty acids.     

The Diversity of Health Effects of Individual <Emphasis Type="Italic">trans</Emphasis> Fatty Acid Isomers

There are multiple adverse effects of trans fatty acids (TFA) that are produced by partial hydrogenation (i.e., manufactured TFA), on CVD, blood lipids, inflammation, oxidative stress, endothelial health, body weight, insulin sensitivity, and cancer. It is not yet clear how specific TFA isomers vary in their biological activity and mechanisms of action. There is evidence of health benefits on some of the endpoints that have been studied for some animal TFA isomers, such as conjugated linoleic acid; however, these are not a major TFA source in the diet. Future research will bring clarity to our understanding of the biological effects of the individual TFA isomers. At this point, it is not possible to plan diets that emphasize individual TFA from animal sources at levels that would be expected to have significant health effects. Due to the multiple adverse effects of manufactured TFA, numerous agencies and governing bodies recommend limiting TFA in the diet and reducing TFA in the food supply. These initiatives and regulations, along with potential TFA alternatives, are presented herein.     

The rearrangement of fatty cyclopropenoids in the presence of boron trifluoride

The destruction of the cyclopropenoid ring system of methyl 9,10 methyleneoctadec-9-enoate (methyl sterculate) with boron trifluoride etherate has been shown to give a complex mixture of products, including methyl esters of C₁₉ allenes (12%), a C₁₈ alkyne (11%) and a variety of C₁₉ and C₂₀ conjugated dienes containing either a methyl or methylene branch. The methylene group lost from the methyl sterculate reactant in the formation of methyl octadec-9-ynoate is incorporated into a second molecule of reactant to yield a mixture of methyl 9-methylene-trans-nonadec-10-enoate and the 11-methylene-trans-9-isomer.