Immobilization of Eversa® Transform via CLEA Technology Converts It in a Suitable Biocatalyst for Biolubricant Production Using Waste Cooking Oil.

The performance of the previously optimized magnetic cross-linked enzyme aggregate of Eversa (Eversa-mCLEA) in the enzymatic synthesis of biolubricants by transesterification of waste cooking oil (WCO) with different alcohols has been evaluated. Eversa-mCLEA showed good activities using these alcohols, reaching a transesterification activity with isoamyl alcohol around 10-fold higher than with methanol. Yields of isoamyl fatty acid ester synthesis were similar using WCO or refined oil, confirming that this biocatalyst could be utilized to transform this residue into a valuable product. The effects of WCO/isoamyl alcohol molar ratio and enzyme load on the synthesis of biolubricant were also investigated. A maximum yield of around 90 wt.% was reached after 72 h of reaction using an enzyme load of 12 esterification units/g oil and a WCO/alcohol molar ratio of 1:6 in a solvent-free system. At the same conditions, the liquid Eversa yielded a maximum ester yield of only 34%. This study demonstrated the great changes in the enzyme properties that can be derived from a proper immobilization system. Moreover, it also shows the potential of WCO as a feedstock for the production of isoamyl fatty acid esters, which are potential candidates as biolubricants.

Anti-echinococcal activity of menthol and a novel prodrug, menthol-pentanol, against Echinococcus multilocularis.

Alveolar echinococcosis is one of the most dangerous parasitic zoonoses. This disease, widely distributed in the northern hemisphere, is caused by the metacestode stage of the tapeworm Echinococcus multilocularis. All surgical and non-surgical patients should perform chemotherapy with benzimidazoles, mainly with albendazole. However, the efficacy of albendazole is variable due to its deficient pharmacokinetic properties. Therefore, the need to find new therapeutic alternatives for the treatment of alveolar echinococcosis is evident. Menthol is a natural compound of low toxicity, used in industries such as cosmetics and gastronomy and generally recognized as safe by the Food and Drug Administration. In addition, menthol has important pharmacological effects and is effective against a wide variety of organisms. The development of prodrugs allows improving the pharmacokinetic properties of the parental drug. To improve lipophilicity and therefore the bioavailability of menthol, a novel prodrug called menthol-pentanol was developed by masking the functional polar group of menthol by linking n-pentanol by a carbonate bond. The aim of the current work was to evaluate the in vitro and in vivo efficacy of menthol and menthol-pentanol against E. multilocularis. Menthol-pentanol had a greater protoscolicidal effect than menthol. In addition, the prodrug demonstrated a similar clinical efficacy to albendazole. The increase in lipophilicity of the prodrug with respect to menthol was reflected in an increase in its antiparasitic activity against E. multilocularis. Thus, menthol-pentanol appears as a promising candidate for further evaluation as a potential alternative for the treatment of alveolar echinococcosis.

Kraft lignin grafted with isopentenol polyoxyethylene ether and the dispersion performance.

In order to develop a biomass-based superplasticizer, kraft lignin (KL) was grafted with isopentenol polyoxyethylene ether (TPEG) to prepare a novel macromonomer (KL-TPEG). It was shown that the retention ratio of the aliphatic CC bond increased from 81.07% to 90.20% with the increase of m(TPEG)/m(KL). When the grafting ratio was increased, the average number of TPEG grafted on one KL molecule was approximately 1.4, 3.1, 4.6, 6.2 and 7.6. The star-like structure was also confirmed by FT-IR, 1H NMR and GPC. KL-TPEG had favorable surface activity and dispersion stability on the cement particles. It was illustrated that the shear stress and shear viscosity of the cement slurries with KL-TPEG were significantly less than that of blank slurry. The dispersion-retention ability of KL-TPEG on the slurry was also gradually enhanced with the increase of the grafting ratio of TPEG. It was seldom reported on the biomass-based TPEG. Through modified with KL, the rheology behavior and the dispersion-retention ability of TPEG was greatly improved, and the cost of TPEG was also reduced, thus this study not only promoted the development of biomass-based macromonomer, but also helped for the high value utilization of lignin.

A Route to Polyprenol Pyrophosphate-Based Probes of O-Polysaccharide Biosynthesis in Klebsiella pneumoniae O2a.

An approach for the assembly of polyprenol pyrophosphate-based probes of O-polysaccharide biosynthesis in Klebsiella pneumoniae serotype O2a is described. This convergent route features high-yielding, diastereoselective glycosylations and the late-stage installation of the polyprenol pyrophosphate moiety. Although applied to the synthesis of a nonasaccharide bearing a farnesyl group (1), the modular nature of the route makes it amenable to the synthesis of additional derivatives containing either larger glycans or different lipid domains.

Preparation of α-Linolenic-Acid-Loaded Water-in-Oil-in-Water Microemulsion and Its Potential as a Fluorescent Delivery Carrier with a Free Label.

Our previous work has demonstrated that α-linolenic acid (ALA)-loaded oil-in-water (O/W) microemulsion could enhance ALA antioxidant capacity. Meanwhile, we also observed that synthesized microemulsion itself had fluorescence. In this work, we have prepared a multiple water-in-oil-in-water (W/O/W) microemulsion to further enhance ALA antioxidant capacity and activate this delivery carrier application potential with a free label. The compositions of primary water-in-oil (W/O) microemulsion were obtained using pseudo-ternary phase diagrams, and then W/O/W microemulsion was prepared adopting the "two-step heterotherm method". The conductivity of W/O/W microemulsion was measured to lie between 250.0 and 350.0 µs/cm. The spherical droplets with a mean particle diameter of 10.0-20.0 nm were confirmed by transmission electron microscopy and dynamic light scattering. Nuclear magnetic resonance confirmed that ALA diffused to the multiple water-oily interface simultaneously. In addition, the in vitro release and antioxidant capacity measurements of ALA-loaded W/O/W microemulsion concluded the sustained-release effect and excellent antioxidant capacity. The fluorescent intensity of W/O/W microemulsion was markedly increased in comparison to O/W microemulsion. The synthesized microemulsion could lead to important applications and have advantages of a label-free fluorescent carrier for optical imaging purposes.

Synthetic polyprenol-pyrophosphate linked oligosaccharides are efficient substrates for mycobacterial galactan biosynthetic enzymes.

Mycobacteria, including the human pathogen Mycobacterium tuberculosis, produce a complex cell wall that is critical for their survival. The largest structural component of the cell wall, the mycolyl-arabinogalactan-peptidoglycan complex, has at its core a galactan domain composed of d-galactofuranose residues. Mycobacterial galactan biosynthesis has been proposed to involve two glycosyltransferases, GlfT1 and GlfT2, which elongate polyprenol-pyrophosphate linked glycosyl acceptor substrates using UDP-galactofuranose as the donor substrate. We here report the first chemical synthesis of GlfT1 and GlfT2 acceptor substrates containing pyrophosphate and polyprenol moieties (compounds 3, 4, 22 and 23). The approach involves chemical synthesis of an oligosaccharide, subsequent phosphorylation at the reducing end and coupling to a polyprenol phosphate. These compounds were shown to be substrates for either GlfT1 (22 and 23) or GlfT2 (3 and 4) and all were substantially more active than the corresponding alkyl glycoside substrates reported previously. Mass spectrometric analysis of the products formed from the reaction of 3, 4, 22 and 23 with the respective cognate enzyme and UDP-galactofuranose provide additional evidence for the galactan biosynthetic model in which GlfT1 adds the first two galactofuranose residues with the remainder being installed via GlfT2. Overall, these results highlight the importance of the pyrophosphate motif in recognition of acceptor substrates by both enzymes and demonstrate a straightforward route for the preparation of such compounds. The work also provides additional support for the process by which this important glycan is biosynthesized using, for the first time, close structural analogs to the natural substrates.

Cleaner emissions from a DI diesel engine fueled with waste plastic oil derived from municipal solid waste under the influence of n-pentanol addition, cold EGR, and injection timing.

Urban planning and development is a decisive factor that increases the automobile numbers which leads to increased energy demand across the globe. In order to meet the escalating requirements of energy, it is necessary to find viable alternatives. Waste plastic oil (WPO) is one such alternative which has dual benefits as it reduces the environmental pollution caused by plastic waste and it could possibly meet the energy requirement along with fossil fuels. The study attempted to reduce emissions from a DI diesel engine fueled with WPO using 30% by volume of n-pentanol with fossil diesel (WPO70P30). EGR (10, 20, and 30%) and injection timing modifications were made with the intention to find optimum engine operating conditions. The experimental results indicated that addition of renewable component like n-pentanol had improved the combustion characteristics by igniting WPO more homogeneously producing a higher premixed combustion phase. Smoke density for WPO70P30 was found to be twice lower than that of neat WPO at standard injection timing of 23°CA bTDC at any given EGR rate, NOx emissions were slightly on the higher side about 12% for WPO70P30 blend against WPO at same operating conditions. WPO70P30 showed lowest smoke and carbon monoxide emissions than diesel and WPO while delivering BTE's higher than WPO and closer to diesel at all EGR and injection timings. However NOx and HC emissions increased with n-pentanol addition. The use of EGR reduced NOx emissions but was found to aggravate other emissions. It was concluded WPO70P30 can be favorably used in a DI diesel engine at the engines advanced injection timing for better performance than diesel with a slight penalty in NOx emissions.

Characterization of essential oil from Ocimum gratissimum leaves: Antibacterial and mode of action against selected gastroenteritis pathogens.

Essential oil of fresh leaves of Ocimum gratissimum (OGEO) was water-steam distilled and analyzed by GC-MS. Thirty-seven compounds were identified, with eugenol (55.6%) as the major component followed by cis-ocimene (13.9%), γ-muurolene (11.6%), (Z,E)-α-farnesene (5.6%), α-trans-bergamotene (4.1%), and ß-caryophyllene (2.7%). Antimicrobial activity of OGEO was tested against four gastroenteritis pathogens (Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, and Shigella flexneri). OGEO exhibited antibacterial effect, with MICs of 1-2 mg ml-1, against the tested species. OGEO also displayed rapid killing effect within 5 s at four times of MIC against both E. coli and S. Typhimurium. Various assays were performed to investigate the mode of action of the oil. OGEO increased the permeability of microbial cell membrane as evidenced by LIVE/DEAD BacLight assay. Analyses of the release of absorbing materials at 260 nm, protein leakage, SDS-PAGE, and SEM strongly suggested the disruptive action of the oil on the cytoplasmic membrane of the tested microorganisms. Results revealed that the antibacterial property of OGEO could be due to membrane disruption.

Identification of a precursor of 2-mercapto-3-methyl-1-butanol in beer.

2-Mercapto-3-methyl-1-butanol (2M3MB) imparts an onion-like off-flavor to beer and is believed to result from the hot aeration of brewer's wort. However, little has been reported regarding the mechanism of formation of 2M3MB. This paper investigates the precursors of 2M3MB formed during the brewing process. Our study of a cysteine conjugate as a precursor showed its negligible contribution to the formation of 2M3MB. The 2M3MB precursor was found to be a volatile compound because 2M3MB was formed in the distillate of hop extract. The precursor was purified through distillation, column chromatography, and preparative gas chromatography, and the 2M3MB-producing potential was measured as an index for estimating the concentration of the precursor. The accurate mass of the precursor was measured using gas chromatography coupled to quadrupole-time-of-flight-mass spectrometry (GC/QTOF). The molecular structure was identified from the product ion spectra by GC/QTOF to be 2,3-epoxy-3-methylbutanal.

LC-MS/MS quantification of felinine metabolites in tissues, fluids, and excretions from the domestic cat (Felis catus).

Domestic cat urine contains large concentrations of the unusual amino acid, felinine (2-amino-7-hydroxy-5,5-dimethyl-4-thiaheptanoic acid). A felinine derivative, 3-mercapt-3-methylbutanol is a potential scent signal for letting other animals know that the scent owners are cats. 3-Methylbutanol-glutathione (MBG) is an upstream precursor of the biosynthetic pathway of felinine that may be produced in hepatocytes by conjugation of glutathione with isopentenyl pyrophosphate, an intermediate for cholesterol biosynthesis. However, little evidence exists to support the biosynthesis of MBG in the liver. This study examined the distribution of metabolites of the felinine biosynthetic pathway in multiple tissues, body fluids, and excretions of cats. MBG, the felinine precursor, 3-methylbutanol-cysteinylglycine (MBCG), felinine, and felinine N-acetyl derivative were quantified by liquid chromatography-electron spray ionization-tandem mass spectrometry. All compounds were detected in cat serum. In males, MBG and MBCG contents were significantly higher than felinine and N-acetylfelinine contents. MBG was detected in multiple tissues, including the salivary gland, heart, liver, spleen, gut, kidney, bladder, adipose tissue, and muscle. Sex differences in MBG levels were observed in the liver and other tissues. Felinine and N-acetylfelinine were also detected in those tissues. Furthermore, we detected all compounds in cat bile and fecal samples, indicating that felinine is excreted into the feces via bile from the liver. We conclude that MBG is synthesized in several tissues in a sex-dependent manner. These findings improve our understanding of felinine metabolism and function in cats.

Stereochemical Divergence of Polyprenol Phosphate Glycosyltransferases.

In the three domains of life, lipid-linked glycans contribute to various cellular processes ranging from protein glycosylation to glycosylphosphatidylinositol anchor biosynthesis to peptidoglycan assembly. In generating many of these glycoconjugates, phosphorylated polyprenol-based lipids are charged with single sugars by polyprenol phosphate glycosyltransferases. The resultant substrates serve as glycosyltransferase donors, complementing the more common nucleoside diphosphate sugars. It had been accepted that these polyprenol phosphate glycosyltransferases acted similarly, given their considerable sequence homology. Recent findings, however, suggest that matters may not be so simple. In this Opinion we propose that the stereochemistry of sugar addition by polyprenol phosphate glycosyltransferases is not conserved across evolution, even though the GT-A fold that characterizes such enzymes is omnipresent.

Characterization, Cytotoxicity, and Genotoxicity of TiO2 and Folate-Coupled Chitosan Nanoparticles Loading Polyprenol-Based Nanoemulsion.

The structure and bioactivity of Ginkgo biloba leaves polyprenol (GBP) are similar to that of dolichol which widely exists in human and mammalian organs. GBP possesses potential pharmacological activities against cancer. This study involved oil-in-water type nanoemulsion (NE) loading GBP was prepared by dissolving polyprenol in nanoemulsion of sodium tripolyphosphate (TPP)/TiO2 solution, Triton X-100, and 1-octanol by inversed-phase emulsification (EIP) and ultrasonic emulsification (UE) method. Folic acid (FA)-coupled chitosan (CS) nanoparticles (NPs), GBP-FA-CS-NPs and GBP-TiO2-FA-CS-NPs, were fabricated by ionic cross-linking of positively charged FA-CS conjugates and negatively charged nanoemulsion with TPP/TiO2. And characterizations of them were investigated by TEM, SEM, FTIR, particle size, and zeta potential. The cytotoxic and genotoxic effects of GBP-TiO2-FA-CS-NP treatment were higher than GBP-NE, GBP-FA-CS-NPs, TiO2-NE, GBP-TiO2-NE, TiO2-FA-CS-NPs, and GBP-TiO2-FA-CS-NP treatment at the same tested concentrations in HepG2 cells. GBP-TiO2-FA-CS-NPs at low TiO2 concentration (from 1 to 2.5 µg/ml) showed good inhibition capacity on HepG2 cells and low cytotoxic and genotoxic effects on HL-7702 cells. The possible mechanism of cytotoxicity on GBP-TiO2-FA-CS-NPs against HepG2 cells is by preventing excessive intracellular Ca2+ into extracellular spaces via inhibiting Ca2+-ATPase and Ca2+/Mg2+-ATPase.

Formulation of hydrophobic peptides for skin delivery via coated microneedles.

Microneedles (MNs) have been investigated as a minimally-invasive delivery technology for a range of active pharmaceutical ingredients (APIs). Various formulations and methods for coating the surface of MNs with therapeutics have been proposed and exemplified, predominantly for hydrophilic drugs and particulates. The development of effective MN delivery formulations for hydrophobic drugs is more challenging with dosing restrictions and the use of organic solvents impacting on both the bioactivity and the kinetics of drug release. In this study we propose a novel formulation that is suitable for MN coating of hydrophobic auto-antigen peptides currently being investigated for antigen specific immunotherapy (ASI) of type 1 diabetes. The formulation, comprising three co-solvents (water, 2-methyl-2-butanol and acetic acid) and polyvinylalcohol 2000 (PVA2000) can dissolve both hydrophilic and hydrophobic peptide auto-antigens at relatively high, and clinically relevant, concentrations (25mg/ml or 12.5mg/ml). The drug:excipient ratio is restricted to 10:1 w/w to maximise dose whilst ensuring that the dry-coated payload does not significantly impact on MN skin penetration performance. The coating formulation and process does not adversely affect the biological activity of the peptide. The delivery efficiency of the coated peptide into skin is influenced by a number of parameters. Electropolishing the metal MN surface increases delivery efficiency from 2.0±1.0% to 59.9±6.7%. An increased mass of peptide formulation per needle, from 0.37µg to 2µg peptide dose, resulted in a thicker coating and a 20% reduction in the efficiency of skin delivery. Other important performance parameters for coated MNs include the role of excipients in assisting dissolution from the MNs, the intrinsic hydrophobicity of the peptide and the species of skin model used in laboratory studies. This study therefore both exemplifies the potential of a novel formulation for coating hydrophobic and hydrophilic peptides onto MN devices and provides new insight into the factors that influence delivery efficiency from coated MNs. Importantly, the results provide guidance for identifying critical attributes of the formulation, coating process and delivery device, that confer reproducible and effective delivery from coated MNs, and thus contribute to the requirements of the regulators appraising these devices.

Mass Spectrometry of Intact Proteins Reveals +98 u Chemical Artifacts Following Precipitation in Acetone.

Protein precipitation in acetone is frequently employed ahead of mass spectrometry for sample preconcentration and purification. Unfortunately, acetone is not chemically inert; mass artifacts have previously been observed on glycine-containing peptides when exposed to acetone under acidic conditions. We herein report a distinct chemical modification occurring at the level of intact proteins when incubated in acetone. This artifact manifests as one or more satellite peaks in the MS spectrum of intact protein, spaced 98 u above the mass of the unmodified protein. Other artifacts (+84, +112 u) also appear upon incubation of proteins or peptides in acetone. The reaction is pH-sensitive, being suppressed when proteins are exposed to acetone under acidic conditions. The +98 u artifact is speculated to originate through an intermediate product of aldol condensation of acetone to form diacetone alcohol and mesityl oxide. A +98 u product could originate from nucleophilic attack on mesityl oxide or through condensation with diacetone alcohol. Given the extent of modification possible upon exposure of proteins to acetone, particularly following overnight solvent exposure or incubation at room temperature, an awareness of the variables influencing this novel modification is valued by proteomics researchers who employ acetone precipitation for protein purification.

Polyprenols of Ginkgo biloba Enhance Antibacterial Activity of Five Classes of Antibiotics.

Polyprenol (GBP) from Ginkgo biloba Leaves (GBL) is an important lipid with many bioactive effects. The effect of GBP on antibacterial properties of five antibiotics belonging to different classes was through analysis of inhibition halos, MIC, and FIC index. And we studied the time-killing curves and Ca(2+) mobilization assay in Staphylococcus aureus cells treated with GBP microemulsion and gentamicin sulfate under MIC/2 conditions. These results showed that the GBP microemulsion (average diameter 90.2 nm) combining with gentamicin sulfate had the highest enhancing antibacterial effect against Staphylococcus aureus, and the MIC value was 33.0 µg/mL. The increase of the antibacterial effect of tested antibiotics was positively correlated with the decrease of the average diameter of GBP microemulsion. Moreover, GBP microemulsion enhanced antibacterial effect and prolonged antibacterial time of GBP combining with gentamicin sulfate against Staphylococcus aureus. GBP microemulsion could enhance the ability of gentamicin inducing an increase in intracellular calcium concentrations to Staphylococcus aureus. GBP microemulsion could help some classes of antibiotics to inhibit or kill bacteria. This study supports the fact that GBP microemulsion obviously can not only reduce the dosage of some classes of antibiotics, but also reduce the frequency of the antibiotic use in vitro.

Hepatotoxicity of illegal home-made alcohols.

OBJECTIVE AND AIM: Alcohol-related hepatotoxicity is not only caused by excessive alcohol consumption but also caused and even accelerated by hepatotoxic ingredients other than ethanol. Concentrations of hepatotoxic substances might be significantly high, particularly in illegally produced home-made alcohols. In this study we aim to analyze the hepatotoxic effects of a home-made alcohol traditionally called "bogma raki" in Turkey. MATERIALS AND METHOD: Fifty Wistar albino male rats were used. Five groups were randomly formed with ten animals in each. Besides laboratory diets, groups were fed as follows: Group 1 (control group) distilled water; Group 2 bogma raki with distilled water (%44 (v/v), 9.2 ml/kg/day); Group 3 bogma raki with distilled water (%44 (v/v), 9.2 ml/kg/day)+walnut (10 g/kg/day); Group 4 whisky with distilled water (%40 (v/v), 9.2 ml/kg/day); Group 5 distilled water + walnut (10 g/kg/day), for 28 days. The toxicological analysis of The spirits were analyzed using Hewlett-Packard (Palo Alto, CA) GC/MS system with HP 6890 gas chromatograph, an HP 5972 mass selective detector (MSD) and an HP 6890 automatic liquid sampler GC/MS; the pressure of the carrier gas helium was 6.0 bar and the split value with a ratio of 1:100. The injection unit temperature set to 250 °C and MS quadrupole temperature set to 280 °C. The MS quadrupole detector ionization energy set to 70 eV. The initial column temperature was 60 °C (for 4 min) programmed by 6 °C/min to final temperature 160 °C and kept for 8 min at 160 °C. Utilized whisky and bogma raki samples were analyzed for the amounts of trans-anethole, ethanol, methanol, 1-propanolol, butanol, 2-butanol, 2-methyl-1-propanolol (isobutanol) and 3-methylbutanol (isoamyl alcohol). Histopathological changes in liver tissues were graded as follows; normal = 0 (<10%), mild = 1 (10%-40%), moderate = 2 (40%-70%), severe = 3 (above 70%). RESULTS: Chemical composition of illegally produced raki sample (%v/v) was as follows: trans-anethole %1.93, ethanol %95.70, 2-methyl-1-propanolol (isobutanol) %0.19, asetic acid %0.25, 3-methylbutanol (isoamyl alcohol) %0.77, and others %1.16. Chemical composition of commercial whisky sample (%v/v) was as follows: ethanol %97.72, 2-methyl-1-propanolol (isobutanol) %0.57, asetic acid %0.23, 3-methylbutanol (isoamyl alcohol) %1.28, and others %0.2. No traces of trans-anethole were detected in whisky. Normal liver morphology was recorded in control and walnut groups. However, bogma raki caused significant congestion and inflammatory cell infiltration compared to control and walnut group. On the other hand, whisky administration caused mild degeneration including inflammation in a limited area. CONCLUSION: Obtained findings suggest that trans-anethole containing alcoholic beverages are more hepatotoxic compared to commercial alcoholic beverages.

How Far Does a Receptor Influence Vibrational Properties of an Odorant?

The biophysical mechanism of the sense of smell, or olfaction, is still highly debated. The mainstream explanation argues for a shape-based recognition of odorant molecules by olfactory receptors, while recent investigations suggest the primary olfactory event to be triggered by a vibrationally-assisted electron transfer reaction. We consider this controversy by studying the influence of a receptor on the vibrational properties of an odorant in atomistic details as the coupling between electronic degrees of freedom of the receptor and the vibrations of the odorant is the key parameter of the vibrationally-assisted electron transfer. Through molecular dynamics simulations we elucidate the binding specificity of a receptor towards acetophenone odorant. The vibrational properties of acetophenone inside the receptor are then studied by the polarizable embedding density functional theory approach, allowing to quantify protein-odorant interactions. Finally, we judge whether the effects of the protein provide any indications towards the existing theories of olfaction.

Development of a standard gas generating vial comprised of a silicon oil-polystyrene/divinylbenzene composite sorbent.

In this work, a highly reproducible standard gas generating vial is proposed. The vial is comprised of a silicon diffusion pump oil spiked with an appropriate calibration compound, such as modified McReynolds probes (benzene, 2-pentanone, pyridine, 1-nitropropane, 1-pentanol, and n-octane), and then mixed with polystyrene/divinylbenzene (PS/DVB) particles. The concentrations of these compounds in gaseous headspace were found to substantially decrease in comparison to previously developed hydrocarbon pump oil based vials; hence, the amount of standard loaded onto SPME fibers was at most, half that of the previous vial design. Depletion for all compounds after 208 successive extractions was shown to be less than 3.5%. Smaller quantities of standards being used resulted in a vial that depleted slower while remaining statistically repeatable over a wider number of runs. Indeed, it was found that depletion could be largely predicted by using a mass balance theoretical model. This behavior allowed a further increase in the number of loadings that could be performed repeatedly. At a 95% level of confidence, the ANOVA test demonstrated that the prepared vials were statistically identical, with no significant intra- or inter-batch differences. In addition, it was found that vials stored under different conditions (e.g. under light exposure, room temperature, and within a refrigerator) were stable over 10 weeks. Silicon based vials proved to be ideal for performing instrument quality control and loading of internal standards onto fibers, both of which are of great importance when performing on-site analysis using portable GC-MS instrumentation and high throughput determinations in laboratory.

Acylation of Antioxidant of Bamboo Leaves with Fatty Acids by Lipase and the Acylated Derivatives' Efficiency in the Inhibition of Acrylamide Formation in Fried Potato Crisps.

This study selectively acylated the primary hydroxyl groups on flavonoids in antioxidant of bamboo leaves (AOB) using lauric acid with Candida antarctica lipase B in tert-amyl-alcohol. The separation and isolation of acylated derivatives were performed using silica gel column chromatography with a mixture of dichloromethane/diethyl ether/methanol as eluents. Both thin layer chromatography and high-performance liquid chromatography analyses confirmed the high efficiency of the isolation process with the purified orientin-6″-laurate, isoorientin-6″-laurate, vitexin-6″-laurate, and isovitexin-6″-laurate that were obtained. The addition of AOB and acylated AOB reduced acrylamide formation in fried potato crisps. Results showed that 0.05% AOB and 0.05% and 0.1% acylated AOB groups significantly (p < 0.05) reduced the content of acrylamide in potato crisps by 30.7%, 44.5%, and 46.9%, respectively.

Kinetic study for the ethanolysis of fish oil catalyzed by lipozyme(®) 435 in different reaction media.

The ethanolysis of fish oil in various reaction medium (tert-pentanol, n-hexane and solvent free system) catalyzed by the immobilized commercial lipase Lipozyme(®) 435 (Candida Antarctica) at atmospheric pressure has been studied in this work. The effect of some kinetic parameters, such as the amount of lipase, temperature and the initial reactant molar ratio ethanol:oil on monoacyglyceride and ethyl ester yield has been analyzed. Experimental data were successfully correlated by a simple kinetic model based on the elementary reactions proposed in this work. At high initial reactant molar ratio the three elementary steps can be considered as irreversible. However the reaction rate constants ratio for the deacylation of monoglyceride to glycerol decreased by decreasing the molar ratio ethanol:oil. The reaction rates are slower in n-hexane as reaction medium compared to tert-pentanol and a solvent-free system, at the experimental conditions essayed in this work. In this last case, ethanol acts as solvent for reaction and as reactant.