Cyclic Fatty Acids Research Articles

Evaluation of physicochemical and tribological properties of chaulmoogra (Hydnocarpus wightianus) oil as green lubricant base stock

Due to environmental concerns, natural oils are increasingly being used as an alternative to mineral oil-based products such as lubricants. However, the use of edible oil for industrial application adversely affects their availability for edible purposes. Chaulmoogra oil is a non-edible oil obtained from the seeds of chaulmoogra tree that grows in wastelands. The fatty acid constituents of vegetable oils determine their properties. Presence of long-chain cyclic fatty acids like chaulmoogric acid, hydnocarpic acid and gorlic acid distinguishes chaulmoogra oil from other oils. Research on how cyclic fatty acids influence the properties of vegetable oils and affect their efficacy as base oils for lubricants is scarce in the literature. This paper presents a preliminary evaluation of the physicochemical, viscometric, oxidative and tribological properties of chaulmoogra oil as a lubricant base stock. Gas chromatography–mass spectroscopy, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy methods were used for structure elucidation. The viscometric analysis was conducted by using Brookfield viscometer. The tribological performance was evaluated by a four-ball apparatus as per ASTM D4172-94. Thermal and oxidative stabilities were evaluated by thermogravimetric/differential thermal analysis in nitrogen and oxygen environments. Pour point was assessed by ASTM D97 method and differential scanning calorimetry. Chaulmoogra oil has a viscosity of 9.2 cSt at 100 ℃ and a viscosity index of 166. Though the coefficient of friction was better than a commercial lubricant of similar viscosity range (SAE 20W40), the wear scar diameter was comparatively higher. Addition of antiwear additive zinc dialkyl dithiophosphate showed considerable improvement in the wear performance of chaulmoogra oil. Chaulmoogra oil showed a high pour point value around 15 ℃ which needs to be improved by appropriate pour point depressants. Environmental advantage, coupled with non-edible nature of chaulmoogra oil, makes it an excellent base stock for lubricants.

Influence of Impurities and Oxidation on Hydroconversion of Waste Cooking Oil into Bio‐jet Fuel

AbstractThe influences of impurities and oxidation evolution of waste cooking oil on the preparation of bio‐jet fuel via hydroconversion were studied. The hydrogenation active sites and acid sites were covered by heavy metals, sulfides, and basic nitrogen compounds, resulting in the increase of selectivity for bio‐jet fuel by decreasing the selectivity of diesel, aromatics, and iso‐alkanes. The effects of impurities, oxidation on the reaction pathway, and product distribution became more distinct with higher catalyst acidity. The evolution and variation of naphthalene, indan, and phenanthrene obtained from cyclic fatty acids influenced the properties of fuel or evoked the catalyst deactivation. This work will help to design new catalysts for selective conversion of waste cooking oil into bio‐jet fuel.

GC‐MS Characterization of Cyclic Fatty Acid Monomers and Isomers of Unsaturated Fatty Acids Formed During the Soybean Oil Heating Process

In this work, the possibility of formation and isolation of cyclic fatty acid monomers (CFAM) from polyunsaturated fatty acids via prolonged heat treatment of soybean oil are studied. The structures of CFAM are determined using Gas chromatography‐Mass spectrometry (GC‐MS) of their 4, 4‐dimethyloxazoline (DMOX) derivatives, the yield of derivatization is 98%. Among CFAM, the cyclohexyl fatty acids with ring from C12 to C17 and the cyclohexneyl with ring from C10 to C15 formed acid are detected by GC‐MS. The new cyclopentyl with ring at C14 position or between C13 to C17 are detected from linoleic acid. Also, the variation of major fatty acids composition of soybean oil during heated treatment at 150, 180, 210, and 240 °C for 60 h are analyzed. The results indicate that after heating, soybean oil contains four isomers of conjugated linoleic acid (CLA), four isomers of C18:1 and four isomers of C18:3. The heating process, the enrichment steps, and CFAM concentration can modify the profile of CFAM and permit the emergence of new compounds, which can be useful to know the edible oil structural changes during the phases of extraction and analysis.Practical Applications: When heated at high temperature for a long time, soybean oil undergoes isomerization and cyclization reactions. In fact, CFAM structures with five and six membered carbon rings are identified from heated oil. A new mass spectrum of the CFAM derivative from the intramolecular C18:2 cyclization is also described. Although CFAM are present at very low concentrations in heated oils, these compounds are the most toxic metabolites produced in soybean oil heated at high temperature. In addition to the four isomers of conjugated linoleic acid, four isomers of C18:1 and four of C18:3 are detected during the heating process. The data clearly show that it is necessary to avoid heating the soybean oil to a temperature above 210 °C for a period of more than 60 h which can minimize the production of CFAM.The gap of 68 amu between the molecular ion (333) and m/z 265 indicate the location of cyclopentyl ring at C14, which is first determined in heated soybean oil.

Pseudomonas aeruginosa Swarmer Cells Adaptation Toward UVc Radiations.

Swarming is the most rapid surface motility allowing Pseudomonas aeruginosa bacteria to rapidly colonize new surfaces. However, swarming behavior is affected by environmental factors like ultraviolet irradiation (UVc). UVc radiation is the most disinfection technology usually applied for wastewater and proven to be effective to inactivate microorganisms. However, efficiency against motile bacteria is not yet studied. This study aims to explain the mechanisms of resistance of swarmer P. aeruginosa cells toward UVc exposure. P. aeruginosa liquid cultures were allowed to swarm across a semisolid surface for 18 h and directly exposed to UVc radiations. Emergent swarmer colonies, revealed after re-incubation, were selected to study biofilm formation, fatty acid (FA) composition, and ultrastructure. Our results showed that membrane adaptation to UVc radiations was seen in Pseudomonas cells by an increase of cyclic fatty acid (CFA) content, confirming the role of cyclopropane in radio-resistance of swarmer cells. Furthermore, electron microscopic study confirmed that over production of S-layer is believed to be a protective form adopted by P. aeruginosa swarmer cells to resist after 5 min of UVc exposure. Moreover, membrane disintegration is the lethal effect observed after 15 min of UVc exposure. In the other hand, study of biofilm production showed an enhancement of biofilm formation, of swarmer cells mainly after 15 min of UVc exposure. There results confirmed that swarming process is highly correlated with particular FA composition of P. aeruginosa membrane and that radio-resistance of swarmer cells is highly supported by CFA biosynthesis and S-layer overproduction.

Influence of naringenin adaptation and shock on resistance of Staphylococcus aureus and Escherichia coli to pulsed electric fields

This work was aimed to investigate the stress induced by naringenin, one of the natural antibacterial components in citrus plants on the resistance of Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 25922 cells to pulsed electric fields (PEF). The results revealed that Staphylococcus aureus and Escherichia coli subjected to naringenin shock (2.0 h) did not significantly change their resistance to the subsequent PEF treatment. However, naringenin adaptation of Staphylococcus aureus and Escherichia coli cells decreased their resistance by exhibiting higher inactivation levels with more damage in cell membrane integrity and more morphological change after being exposed to PEF treatment. This difference in response to PEF treatment for Staphylococcus aureus and Escherichia coli might be due to the difference in the alterations of membrane fatty acids during preliminary naringenin exposure. Staphylococcus aureus adapted to naringenin remarkably increased the content of anteiso-branched chain fatty acids and simultaneously decreased the levels of straight and iso-branched chain fatty acids, whereas Escherichia coli cells caused a significant increase of unsaturated fatty acids at the expense of saturated and cyclic fatty acids. Comparatively, no significant changes were observed in the membrane fatty acid composition of cells after being subjected to naringenin shock.

Gas chromatography-mass spectrometry of sapucainha oil (Carpotroche brasiliensis) triacylglycerols comprising straight chain and cyclic fatty acids.

Sapucainha oil, which may be used to treat leprosy, comprises straight chain and cyclic fatty acids (FA), and triacylglycerols (TAG). The FA and TAG content of the oil sample was analysed using gas chromatography-electron ionisation mass spectrometry (GC-EIMS). FA analysis was performed after derivatisation to fatty acid methyl esters (FAME). For free FA and TAG analysis, the oil sample was dissolved in hexane and injected into a short, high-temperature column, for GC with MS analysis. Free FA and FAME were tentatively identified based on mass spectrum information of their molecular and fragment ions, as well as library matching. Overlapping TAG peaks were deconvoluted based on mass fingerprint data. The FA composition was utilised to predict possible TAG identities. FA residues of TAG were identified based on characteristic fragment ions, such as [M-RCO2]+, [RCO+128]+, [RCO+74]+ and RCO+ where R is the aliphatic hydrocarbon chain. FAME analysis showed that the cyclic FA hydnocarpic (36.1%), chaulmoogric (26.5%) and gorlic (23.6%) acids were the major components. In addition, straight chain FA such as palmitic, palmitoleic, stearic, oleic and linoleic acids were detected. Palmitic, oleic, hydnocarpic, chaulmoogric and gorlic acids were also detected as free FA in the oil sample. Six groups of TAG peaks were eluted from GC at temperatures ≥330°C. After deconvolution and mass spectrum analysis, each TAG peak group was revealed to comprise 2 to 5 co-eluted TAG molecules; >18 TAG were identified. These TAG consisted of a mix of both cyclic and straight chain FA, but were mostly derived from cyclic FA.

Presence of cyclopropane fatty acids in foods and estimation of dietary intake in the Italian population

Cyclopropane fatty acids (CPFAs) are the most abundant cyclic fatty acids in microorganisms with unknown role(s) regarding their dietary relevance and biological effects in humans. This work was aimed to draw up a list of CPFAs-containing foods for estimating their dietary intake in the Italian population to provide a basis for evaluating their nutritional relevance and potential health-related effects. The CPFAs content of more than 500 food items was investigated and a preliminary dietary intake was assessed (12.0 ± 6.0 mg/day), based on the data reported by the Italian National Food Consumption Survey INRAN-SCAI 2005–06. CPFAs should be considered of dietary relevance in view of their potential physiological activity in humans and their presence in significant amounts in dairy products, as Grana Padano cheese (9.0–30.0 mg/100 g), and in bovine meat (0.7–4.0 mg/100 g). Future studies should elucidate whether this uncommon class of fatty acids has a biological role in human health.

Liver and plasma lipid changes induced by cyclic fatty acid monomers from heated vegetable oil in the rat.

Cyclic fatty acid monomers (CFAM) generated through domestic or industrial heating of vegetable oils may alter liver enzymes and induce hepatomegaly and steatosis, but the underlying mechanisms are not clearly understood. This study aimed to assess the effects of CFAM on liver and plasma lipids and to determine whether these effects are modulated by dietary lipids. Thirty‐six (36) male Wistar rats were fed either of the four isoenergetic diets consisting of canola oil or soybean oil with/without 500 mg/100 g CFAM of total fat for 28 days. Rats fed CFAM had higher liver total lipids (p = 0.03) and triacylglycerols (TAG) (p = 0.02), but less hepatic phosphatidylcholine (p = 0.02) compared to those fed the non‐CFAM diets. CFAM did not alter liver phosphatidylethanolamine N‐methyltransferase (PEMT) activity and CTP: phosphocholine cytidylyltransferase (CT‐α) protein levels. Rats fed CFAM diets had higher levels of plasma total cholesterol (TC), VLDL + LDL cholesterol, higher ratio of TC to HDL cholesterol, and lower levels of HDL cholesterol compared with rats fed non‐CFAM diets (p < 0.05). Plasma alanine transaminase (ALT) was decreased with CFAM, but plasma insulin, glucose, and TAG did not vary among the four diet groups (p < 0.05). Rats fed canola oil and CFAM had higher plasma levels of aspartate transaminase (AST) and AST/ALT ratio compared with the other three diet groups. These results indicate that CFAM may provoke an accumulation of TAG in the liver related to a decrease in phosphatidylcholine (PC) levels, but the effect of CFAM on PC concentrations may not occur through impairment of the two main PC biosynthesis pathways.

Variations in cellular membrane fatty acid composition ofEscherichia coliin resistance to pulsed electric fields induced by eugenol

Eugenol (EUG; 4-allyl-2-methoxyphenol) is a natural antibacterial component from essential oil. The effects of EUG on cell membrane fatty acid composition, membrane fluidity and resistance to pulsed electric field (PEF) of Escherichia coli ATCC 8,739 (E. coli) were investigated. Results indicated that the PEF resistance of E. coli decreased as EUG concentration increased, which may be related to the alterations in membrane fatty acid composition and fluidity. Gas chromatography−mass spectrometry and micro-Raman spectroscopy showed that EUG increased membrane fluidity by notably increasing the proportion of unsaturation fatty acids and simultaneously decreasing the content of cyclic fatty acids. These results revealed that PEF resistance of E. coli was influenced by EUG due to alterations of fatty acid composition and membrane fluidity. Practical applications Pulsed electric field (PEF), as a widely used non-thermal sterilization technology, has gained much attention and increasingly focused on improving the efficiency to inactivate micro-organisms. Eugenol (EUG; 4-allyl-2-methoxyphenol) derived from cloves is a natural phenol essential oil and exhibits several pharmacological properties such as being an antimicrobial. Our results revealed the underlying mechanism that EUG reduced PEF resistance of E. coli cells and contributed to achieve better understanding of microbial inactivation by PEF. Therefore, a new route for the application of eugenol to improve the efficiency of PEF in the food industry was created.

Transcriptomic approach and membrane fatty acid analysis to study the response mechanisms of Escherichia coli to thyme essential oil, carvacrol, 2-(E)-hexanal and citral exposure.

The application of essential oils (EOs) and their components as food preservatives is promising but requires a deeper understanding of their mechanisms of action. This study aims to evaluate the effects of thyme EO, carvacrol, citral and 2-(E)-hexenal, on whole-genome gene expression (the transcriptome), as well as the fatty acid (FA) composition of the cell membranes of Escherichia coli K12. Therefore, we studied the response against 1h of exposure to sublethal concentrations of natural antimicrobials, of exponentially growing E.coli K12, using DNA microarray technology and a gas chromatographic method. The results show that treatment with a sublethal concentration of the antimicrobials strongly affects global gene expression in E.coli for all antimicrobials used. Major changes in the expression of genes involved in metabolic pathways as well as in FA biosynthesis and protection against oxidative stress were evidenced. Moreover, the sublethal treatments resulted in increased levels of unsaturated and cyclic FAs as well as an increase in the chain length compared to the controls. The down-regulation of genes involved in aerobic metabolism indicates a shift from respiration to fermentative growth. Moreover, the results obtained suggest that the cytoplasmic membrane of E.coli is the major cellular target of EOs and their components. In addition, the key role of membrane unsaturated FAs in the response mechanisms of E.coli to natural antimicrobials has been confirmed in this study. The transcriptomic data obtained signify a further step to understand the mechanisms of action of natural antimicrobials also when sublethal concentrations and short-term exposure. In addition, this research goes in deep correlating the transcriptomic modification with the changes in E.coli FA composition of cell membrane identified as the main target of the natural antimicrobials.

Effects of Cyclic Fatty Acid Monomers from Heated Vegetable Oil on Markers of Inflammation and Oxidative Stress in Male Wistar Rats.

This study assesses the effects of cyclic fatty acid monomers (CFAM) from heated vegetable oils on oxidative stress and inflammation. Wistar rats were fed either of these four diets for 28 days: canola oil (CO), canola oil and 0.5% CFAM (CC), soybean oil (SO), and soybean oil and 0.5% CFAM (SC). Markers of oxidative stress and inflammation were determined by micro liquid chromatography tandem mass spectrometry (micro-LC-MS/MS) and enzyme-linked immunosorbent assay (ELISA) kits, respectively. Analysis of variance (ANOVA) for a 2 × 2 factorial design was performed to determine the CFAM and oil effects and interactions between these two factors at P ≤ 0.05. For significant interactions, a post hoc multiple comparison test was performed, i.e., Tukey HSD (honest significant difference) test. CFAM induced higher plasma levels of 15-F2t-IsoP (CC, 396 ± 43 ng/mL, SC, 465 ± 75 ng/mL vs CO, 261 ± 23 ng/mL and SO, 288 ± 35 ng/mL, P < 0.05). Rats fed the SC diet had higher plasma 2,3-dinor-15-F2t-IsoP (SC, 145 ± 9 ng/mL vs CC, 84 ± 8 ng/mL, CO, 12 ± 1 ng/mL, and SO, 12 ± 1 ng/mL, P < 0.05), urinary 2,3-dinor-15-F2t-IsoP (SC, 117 ± 12 ng/mL vs CC, 67 ± 13 ng/mL, CO, 15 ± 2 ng/mL, and SO, 18 ± 4 ng/mL, P < 0.05), and plasma IL-6 (SC, 57 ± 10 pg/mL vs CC, 48 ± 11 pg/mL, CO, 46 ± 9 pg/mL, and SO, 44 ± 4 pg/mL, P < 0.05) than the other three diet groups. These results indicate that CFAM increased the levels of markers of oxidative stress, and those effects are exacerbated by a CFAM-high-linoleic acid diet.

Identification of bottlenecks in the accumulation of cyclic fatty acids in camelina seed oil.

SummaryModified fatty acids (mFA) have diverse uses; for example, cyclopropane fatty acids (CPA) are feedstocks for producing coatings, lubricants, plastics and cosmetics. The expression of mFA‐producing enzymes in crop and model plants generally results in lower levels of mFA accumulation than in their natural‐occurring source plants. Thus, to further our understanding of metabolic bottlenecks that limit mFA accumulation, we generated transgenic Camelina sativa lines co‐expressing Escherichia coli cyclopropane synthase (EcCPS) and Sterculia foetida lysophosphatidic acid acyltransferase (SfLPAT). In contrast to transgenic CPA‐accumulating Arabidopsis, CPA accumulation in camelina caused only minor changes in seed weight, germination rate, oil accumulation and seedling development. CPA accumulated to much higher levels in membrane than storage lipids, comprising more than 60% of total fatty acid in both phosphatidylcholine (PC) and phosphatidylethanolamine (PE) versus 26% in diacylglycerol (DAG) and 12% in triacylglycerol (TAG) indicating bottlenecks in the transfer of CPA from PC to DAG and from DAG to TAG. Upon co‐expression of SfLPAT with EcCPS, di‐CPA‐PC increased by ~50% relative to lines expressing EcCPS alone with the di‐CPA‐PC primarily observed in the embryonic axis and mono‐CPA‐PC primarily in cotyledon tissue. EcCPS‐SfLPAT lines revealed a redistribution of CPA from the sn‐1 to sn‐2 positions within PC and PE that was associated with a doubling of CPA accumulation in both DAG and TAG. The identification of metabolic bottlenecks in acyl transfer between site of synthesis (phospholipids) and deposition in storage oils (TAGs) lays the foundation for the optimizing CPA accumulation through directed engineering of oil synthesis in target crops.

Determination of Cyclopropane Fatty Acids in Food of Animal Origin by 1H NMR.

Cyclopropane fatty acids (CPFAs) are unusual fatty acids of microbial origin, recently detected in milk and dairy products. CPFAs have been demonstrated to be interesting molecular markers for authentication of dairy products obtained without ensiled feeds. Moreover, they can also be recognized as a new secondary component of human diet. Information is lacking on the presence of cyclic fatty acids in other food sources. Cyclopropane fatty acids have been detected by GC-MS analysis in cheese and other animal fats in concentration ranging from 200 to 1000 mg/kg fat, but in some cases, the complex fatty acid profile and the possible presence of interfering peaks make the separation not straightforward and the quantification uneasy. Therefore, a new reliable 1H NMR method was developed to detect and measure CPFA content in different foods of animal origin, based on the detection of the characteristic signals of cyclopropane ring. The 1H NMR (600 MHz) method showed detection limits comparable with those of full scan GC-MS, and it allowed the identification and quantitation of the cyclopropane fatty acids in different foods.

Effects of cyclic fatty acids on rat liver and plasma fatty acid metabolism and inflammation mediators depend on dietary lipids

ObjectiveThis study aimed to determine the interactions between dietary fatty acids and cyclic fatty acid monomers (CFAM) on liver and plasma lipids and inflammationMethodsTwo oils (canola oil and soybean oil) were used in the experiment while 0.5% of CFAM were added to the CFAM diets, thus generating four diet groups: canola oil (CO), soybean oil (SO), canola oil and CFAM (CC), and soybean oil and CFAM (SC). 36 male Wistar rats (n=9) were fed those diets for 28 days, liver and plasma lipids were analyzed by gas‐liquid chromatography and inflammation markers were analyzed enzymatic methods.ResultsAlthough CFAM alone induced an accumulation of TAG, liver fatty acid analysis showed that rats fed the CC diet had less stearic acid (STA), arachidonic acid (ARA), and docosahexaenoic acid (DHA) but more oleic acid (OLA) and total MUFA than those fed the CO, SO and SC diets. However, no difference was observed between rats fed SO and SC diets. Significant interactions between the type of oil and CFAM were also observed in plasma fatty acids for the following fatty acids: palmitic acid (PAM, P = 0.039), linoleic acid (AL, P = 0.023), docosapentaenoic acid (DPAn‐3 P&lt;0.0001), and total PUFAn‐3 (P = 0.028). In particular, it was observed that CC‐fed rats had less AL than the SC (P&lt;0.0001). CFAM induced lower ALT levels (P&lt;0.0001), lower ALT/AST ratio (P = 0.003), and higher plasma total cholesterol levels (P = 0.024) compared with the non‐CFAM diets. There were interactions between oil and CFAM for plasma AST (P = 0.04), AST/ALT ratio (P = 0.02), and IL‐6 (P = 0.02).ConclusionsWhile showing that CFAM effects on lipid metabolism are exacerbated when used with a high‐oleic acid oil, these results suggest that CFAM effects are altered by dietary lipids. These results reinforce the need for a selected use of vegetable oils in domestic and industrial settings. Other associations of CFAM with oils of different ratios MUFA/PUFA, PUFAn‐6/n‐3, PUFA/SFA can be used to further assess the interactions between CFAM and dietary fats.Support or Funding InformationCanadian Natural Sciences and Engineering Research Council

Fatty Acid Profiles of Garuga floribunda, Ipomoea pes‐caprae, Melanolepis multiglandulosa and Premna odorata Seed Oils

AbstractThe fatty acid profiles of the seed oils of four species from four plant families for which no or only sparse information on the fatty acid profiles is available are reported. The four seed oils are Garuga floribunda of the Burseraceae family, Ipomoea pes‐caprae, of the Convolvulaceae family, Melanolepis multiglandulosa of the Euphorbiaceae family, and Premna odorata of the Labiatae (Lamiaceae) family. Linoleic acid is the most abundant in three seed oils, except I. pes‐caprae in which oleic acid is most abundant. These two acids are overall the most abundant in all four seed oils studied. Of the four seed oils investigated, only G. floribunda contains minor amounts of a cyclic fatty acid (dihydrosterculic acid).

Effect of combined long-term starvation and γ-irradiation on membrane fatty acids and cell surface hydrophobicity of Salmonella enterica serovar Typhimurium

This study was carried out to explore the adaptive mechanisms of Salmonella enterica serovar Typhimurium, in particular the implication of fatty acids (FA) in the remodeling of membrane lipid composition to overcome the combined effects of long-term starvation and γ-irradiation stresses. In addition, cell surface hydrophobicity was also evaluated. The bacterial strains (control and starved) were treated with a nonlethal γ-irradiation dose of 0.5 kGy and sublethal doses of 1 kGy. Gas chromatography analysis showed that the FA composition of starved and γ-irradiated cells was modified. However starvation combined with γ-irradiation induced more modifications in the FA composition than γ-irradiation or starvation alone. Indeed, the unsaturated FA-to-saturated FA ratio decreased significantly for both strains compared with γ-irradiated cells, as main consequence of the cyclic FA formation. Our results showed that starvation, irradiation, or combined stresses significantly influenced the hydrophobicity, and this may have affected the virulence state of Salmonella Typhimurium cells. This study represents one of the few to demonstrate the modifications on bacterial membrane as a cellular response to survive to the ionizing radiation combined with long-term starvation stress.

МЕТАБОЛІЧНІ ПРОЦЕСИ В РУБЦІ ТА ПРОДУКТИВНИЙ ЕФЕКТ У ТЕЛЯТ ЗА ДІЇ ЙОНОФОРУ

Functions tricarboxylic acid and a cyclic fatty acid synthesis process is only possible under normal carbohydrate metabolism. It is therefore important to know the nature of the normal state of metabolism in the rumen and the reasons for its violations, and have the knowledge and skill in time to influence exogenous factors. Among the latter is particularly important metabolic engineering that by constructing the scale and speed of the cascade of reactions major transformations appropriate combinations of substrates and other effectors, yields on high–quality animals and productive effect.The article presents experimental data on the effect of antibiotic feed additive monensin on metabolic processes in the rumen of calves and its productive effect. The results of carbohydrate metabolism studies with mixed populations of microorganisms rumen of ruminant animals of the additive ionophore expand the existing information about its role in the assimilation of nutritious diet substances, as well as complementary data on the features of influence on of intermediate exchange and productive effect of exogenous factors substrate–ergotropic complex that, in ultimately, it allows the construction of a significant acceleration of anabolic and achieve high levels of performance.Research evidence that growing calves, especially when switching to vegetarian diet, supplements ionophore significant effect on scar of intermediate metabolism.Feeding calves antibiotic feed additive monensin at a dose of 0.5 g/kg body weight per day, showing a measurable impact on the metabolic processes in the rumen, especially during the habituation of animals to the vegetation and in subsequent periods of feeding. This effect is primarily a change in the molar ratio of VFA (increase the molar proportion of propionate at the expense of acetate), and the average daily gain in growth by 10.4% (1037 against 939 g).

Application of Chromatographic Techniques in the Detection and Identification of Constituents Formed during Food Frying: A Review

AbstractFrying is one of the most popular food processing methods. However, many physicochemical reactions occur during frying, forming complex products in both the frying oil and the fried food. Chromatographic techniques have been successfully applied to characterize the products formed during food‐frying or during a simulated frying process. In this review, the specific products analyzed by gas chromatography (GC) and high‐performance liquid chromatography (HPLC) are elucidated in detail. The most studied components are polar compounds (such as volatile compounds, hydrolysis products, oxidized triacylglycerol [TAG] decomposition products, oxidized TAG monomers, sterol oxides, oxygenated TAG polymers, and acrylamide) and nonpolar compounds (such as cyclic fatty acid monomers and trans isomers), which are classified based on their polarity. However, the definite structures of TAG polymers and sterol oxides, and polymers analyzed by GC or HPLC‐based methods are only investigated in modeled reactions. Furthermore, some of the sample pretreatments and chromatographic methods are only used to analyze the known products. A number of earlier trace amounts of undetected products need to be investigated by more effective detection techniques. The development of multidimensional chromatographic techniques and elaborate mass spectrometry detectors makes composition analysis possible for the food‐frying process, which may effectively promote the development of quality monitoring and nutrition evaluation for the fried foods.

Cyclic fatty acids found in frying oils are detoxified via classical drug metabolic pathway but also by β-oxidation and eliminated as conjugates in rats.

Cyclic fatty acid monomers (CFAM) are mainly formed during heat treatments, such as frying, of edible oils. These fatty acids are mixtures of disubstituted five- or six-carbon-membered ring structures. Some earlier studies have suggested that some of these molecules could be metabolized and detoxified, but so far, neither the detoxification mechanisms nor the metabolite identifications have been elucidated. The objective of the present study was to identify the metabolites resulting from the metabolism and detoxification of CFAM. A deuterium-labeled CFAM, [9-(2)H]-10-(6-propyl-2-cyclohexenyl)-dodecenoic acid, was synthesized and fed to rats for 3 days, along with a standard chow diet while the control group was fed the same chow diet which did not contain any CFAM. Biological fluids (urine, blood) were collected for both groups of rats and analyzed using an untargeted metabolomic approach by ultra-performance liquid chromatography coupled with mass spectrometry. Two discriminant metabolites and 18 molecules derived from CFAM were identified or tentatively identified in plasma and urine samples, respectively. The structures of the metabolites suggest that CFAM having a six-carbon-membered ring could be detoxified by the classical drug metabolic pathway (phase I and phase II reactions), but our study also indicates that these are substrates for the β-oxidation pathway and eliminated as glucuronide, sulphate, and/or nitrate conjugates. Urine metabolomics investigations without diet effects have indicated a higher excretion of medium-chain acylcarnitines in the D-CFAM diet group, which may indicate an incomplete β-oxidation.

Cyclopropanation of unsaturated fatty acids and membrane rigidification improve the freeze-drying resistance of Lactococcus lactis subsp. lactis TOMSC161.

This work aimed at characterizing the biochemical and biophysical properties of the membrane of Lactococcus lactis TOMSC161 cells during fermentation at different temperatures, in relation to their freeze-drying and storage resistance. Cells were cultivated at two different temperatures (22 and 30°C) and were harvested at different growth phases (from the middle exponential phase to the late stationary phase). Bacterial membranes were characterized by determining the fatty acid composition, the lipid phase transition, and the membrane fluidity. Cultivability and acidification activity losses of L. lactis were quantified after freezing, drying, and 3months of storage. The direct measurement of membrane fluidity by fluorescence anisotropy was linked to lipid composition, and it was established that the cyclopropanation of unsaturated fatty acids with concomitant membrane rigidification during growth led to an increase in the freeze-drying and storage resistance of L. lactis. As expected, cultivating cells at a lower fermentation temperature than the optimum growth temperature induced a homeoviscous adaptation that was demonstrated by a lowered lipid phase transition temperature but that was not related to any improvement in freeze-drying resistance. L. lactis TOMSC161 was therefore able to develop a combined biochemical and biophysical response at the membrane level during fermentation. The ratio of cyclic fatty acids to unsaturated fatty acids (CFA/UFA) appeared to be the most relevant parameter associated with membrane rigidification and cell resistance to freeze-drying and storage. This study increased our knowledge about the physiological mechanisms that explain the resistance of lactic acid bacteria (LAB) to freeze-drying and storage stresses and demonstrated the relevance of complementary methods of membrane characterization.