4-ethylphenol Research Articles

Dekkera and Brettanomyces growth and utilisation of hydroxycinnamic acids in synthetic media

Dekkera and Brettanomyces yeast are important spoilage organisms in a number of food and beverage products. Isolates of both genera were cultured in a defined medium and supplemented with hydroxycinnamic acids and vinylphenols to investigate their influence on growth and the formation of ethyl phenol derivatives. The growth rate of Brettanomyces species in the presence of acids was reduced, and no significant conversion to vinyl or ethyl derivatives was observed. The growth rate and substrate utilisation rates of Dekkera anomala and Dekkera bruxellensis yeast differed depending on strain and the acid precursor present. Growth of D. bruxellensis was slowed by the presence of ferulic acid with the addition of 1 mM ferulic acid completely inhibiting growth. This study provides an insight into the spoilage potential of these organisms and possible control strategies involving hydroxycinnamic acids.

Content of dietary fermentable protein and odour from pig manure

An experiment was conducted in growing pigs to determine the effects of content of potentially fermentable protein (FP) on odour and ammonia emissions from pig manure and on manure characteristics. Pigs ( n = 18) were allocated in a randomised complete block arrangement with 3 treatments in each of 6 blocks. The three treatments had 28.4, 38.2 and 48.0 g fermentable protein per kg of feed. Pigs with an initial body weight (BW) of 41.3 ± 3.2 kg (mean ± S.D.) were housed individually in pens with partly slatted floor and offered a daily feed allowance of 2.8 × maintenance requirement (293 kJ net energy (NE)/BW 0.75). Feed was mixed with water (1/2.5; w/w). After a 2-week adaptation period faeces and urine produced by each pig were collected in individual manure pits under the slatted floor. In the 5th week of the collection period air samples were collected from each manure pit for odour and ammonia analyses. Odour characteristics were measured by olfactometry and ammonia was measured by using two ammonia traps each containing 20 ml 0.5 M HNO 3 solution. Manure samples from each manure pit, taken in the same week as air samples, were analysed for volatile fatty acids (VFAs), indolic, phenolic, sulphurous compounds, ammonium nitrogen and total nitrogen concentrations. Data were evaluated using analysis of variance. Odour and ammonia emissions from pig manure were in the range from 1.88 to 2.78 ou E/(s m 2) and from 0.011 to 0.014 mg/(s m 2), respectively and were not affected by fermentable protein content of the diet (P >0.05). Increased fermentable protein content resulted in higher concentrations of total nitrogen, methyl sulphide, carbon disulphide, ethanethiol, phenol, 3-methyl indole and 4-ethyl phenol in the manure (P <0.01), but did not influence ammonium nitrogen, volatile fatty acids, cresols and indole concentrations in the manure. It is concluded that a decrease in the fermentable protein content of the diet does not reduce odour emission, odour intensity (OI) or odour hedonic tone (HT) in pigs.

Identification of Odor Causing Compounds in a Commercial Dairy Farm

The odorous air emissions from confined animal feeding operations (CAFOs), such as swine, poultry and dairy farms, are increasingly raising community complaints. Odorous emissions can result in health damages, psychological discomforts and adverse aesthetic effects in the community. However, these emissions are not well characterized up to now due to the lack of legislation, the limitations in sampling and instrumentation techniques, and the complexity of the emissions themselves. This study is aimed at the development of a high volume sampler and sorbent assembly to identify the odor causing compounds from a diary CAFO. The sorbent was custom designed to target the potential compounds that may exist in a dairy farm and was validated in laboratory with a synthetic odor from the swine manure. The actual samples at the diary farm were collected in spring and summer of 2005. The sorbents were solvent extracted and individual odor compounds were identified using GC–MS (gas chromatography–mass spectroscopy). The data obtained indicated that high volume sampling can shorten the sampling time from days to within 4 h. Both volatile organic compounds (VOCs) and volatile fatty acids (VFAs) have been identified from the dairy farm, such as phenol, methylphenol, 4-ethyl phenol, indole, methyl indole, benzyl alcohol, hexanoic acid, valeric acid and iso-valeric acid, together with some nitrogen containing compounds that have not been reported before.

Effects of dietary crude protein level on odour from pig manure

The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, hedonic tone, and ammonia emission from pig manure and on manure composition (pH, total nitrogen, ammonium, volatile fatty acids, indolic, phenolic and sulphur-containing compounds). An experiment was conducted with growing pigs (n = 18) in a randomised complete-block design with three treatments in six blocks. Treatment groups were 12%, 15% and 18% CP diets. Barley was exchanged for soya-bean meal. Crystalline amino acids (AA) were included in the 12% CP diet up to the level of pigs' requirement; the same amount of AA was added to the 15% and 18% CP diets. Pigs with an initial body weight (BW) of 36.5 ± 3.4 kg (mean ± s.d.) were individually penned in partly slatted floor pens and offered a daily feed allowance of 2.8 × maintenance requirement for net energy (NE: 293 kJ/kg BW0.75). Feed was mixed with water, 1/2.5 (w/w). Faeces and urine of each pig were accumulated together in a separate manure pit under the slatted floor. After an adaptation period of 2 weeks, the manure pits were cleaned and manure was collected. In the 5th week of the collection period, air samples for odour and ammonia analyses, and manure samples were collected directly from each manure pit. Air samples were analysed for odour concentration and for hedonic value and intensity above odour detection threshold. Manure samples were analysed for volatile fatty acids, and indolic, phenolic and sulphurous compounds, ammonium and total nitrogen concentrations. Reducing dietary CP from 18% to 12% lowered odour emission ( P < 0.05) and ammonia emission ( P = 0.01) from pig manure by 80% and 53%, respectively. Reduced dietary CP decreased total nitrogen, methyl sulphide, carbon disulphide, ethanethiol, phenol, 4-ethyl phenol, indole and 3-methyl indole concentrations in the manure ( P < 0.05). Volatile fatty acids and cresols concentrations in the manure of pigs fed different dietary CP levels were similar. A reduction of dietary CP and at the same time providing essential AA is an option to reduce odour emission as well as ammonia emission from pig manure.

Synthesis and characterization of novel bead-shaped insoluble polymer-supported tri-site phase transfer catalyst and its efficiency in N-alkylation of pyrrole

Abstract A new bead-shaped insoluble polymer-supported multi-site (tri-site) phase transfer catalyst (PS-MPTC) viz., polymer-supported 4-(2,2,2-tris[triethylammoniummethylene chloride]-1-hydroxy ethyl) phenylether (PSTTEACHPE) has been synthesized by following a simplified procedure. Initially, polystyrene-based cross-linked beads was prepared by allowing the reaction using 2% divinylbenzene (as a cross linking monomer), 25% vinylbenzyl chloride (as a functional monomer) and styrene (as supporting monomer) to proceed through a suspension copolymerization method. The obtained terpolymer beads containing pendant benzyl chloride groups were condensed with 4-(2,2,2-tris[triethylammonium methylene chloride]-1-hydroxy ethyl) phenol, followed by quaternization using triethylamine, resulting in the formation of polymer-supported 4-(2,2,2-tris[triethylammoniummethylene chloride]-1-hydroxy ethyl) phenyl ether (PSTTEACHPE). Then the presence of tri-active site in PSTTEACHPE was examined by FT-IR, 1 H NMR, 13 C NMR, [chloride ion] and SEM analyses. The comparative results of [chloride ion] and the peak intensity of C–N stretching (quaternary onium group) in FT-IR were found to increased three fold in PSTTEACHPE on comparing with their similar types of polymer-supported bead-shaped single-site PTC (PS-BSPTC); thus we confirmed the presence of three active sites. The surface morphology study through SEM shows that the PSTTEACHPE is heterogeneous in nature with tiny nodules; whereas the single-site PS-BSPTC shows smooth homogeneous nature; this is an another piece of evidence for the availability of more numbers of active sites in PSTTEACHPE. Further, the catalytic efficiency of this new PSTTEACHPE was ascertained by N -alkylation of pyrrole with benzylchloride using 30% (w/v) aqueous sodium hydroxide at 60 °C. The pseudo-first order rate constants were calculated by following the disappearance of pyrrole through gas chromatography. The observed rate constants were found to be three-fold higher for PSTTEACHPE than with PS-BSPTC, which again confirmed the presence of three active-sites. Investigations were also made on kinetic variables such as stirring speed, [substrate], [catalyst], [NaOH] and temperature; it is observed that each variable is influenced the rate of reaction. From the Arrhenius plot, the activation energy and thermodynamic parameters were evaluated as 12.44, −7.99, 10.99 and 13.25 kcal mol −1 for E a , Δ S # , Δ H # and Δ G # respectively. Based on the observed kinetic and thermodynamic results, an interfacial mechanism was proposed for the N -alkylation of pyrrole.

Reactions of Coal Model Compounds in Tetralin Using Microwave Energy: Effects of Catalysts

Reaction mechanisms of model compounds of coal in tetralin by microwave energy were investigated. Diphenylmethan (DFM), phenyl-methyl ether (anisole), and phenyl-methyl ketone (acetophenon) were chosen as model compounds. Experiments were carried out for 10 minutes of microwave energy and different catalysts were used (pyratol, zeolite, BaCl2, AlNiMo) to find out the distribution of reaction products of the model compounds. GC and GC/MS are used to analyze the reaction products. The main reaction products from DFM and tetralin under microwave radiation with catalysts were ethyl benzene, naphthalene, 2-methyl naphthalene, 3,4-dihydronaphthaleneone, 1-1′-ethyldene 1-benzene, and 1-methyl 4-phenyl methyl benzene. The main reaction products from anisole and tetralin under microwave radiation were ethyl benzene, phenol, methyl phenol, decahydronaphthalene, and tetrahydronaphthalenol. The main reaction products from acetophenon and tetralin under microwave radiation with catalysts were ethyl benzene, methoxy benzene, decahydronaphthalene, naphthalene, tetrahydronaphthalenol, 3,4-dihydronaphthalenone and 2-butene-1-one-1,3 diphenyl. The estimated mechanism of the model compounds with tetralin is compared with the results taken from GC/MS analysis. It is obtained that the results suggested theoretically were similar with the GC/MS results.

Solid-Phase Microextraction in the Analysis of Food Taints and Off-Flavors

Selected food taints and off flavors, for which solid phase microextraction (SPME) has been used as a method for volatiles isolation, are the subject of review. Compounds responsible for musty and earthy odor off-flavors and taints in foods are discussed. This group contains haloanisoles, geosmin, and methylisoborneol. Chlorophenols are discussed as precursors of chloroanisoles and compounds impairing the flavor of food. Also described are volatile phenolic compounds responsible for medicinal off flavors, mainly ethyl phenols and vinyl phenols. Sulfur compounds that contribute to off-flavor are also discussed. Finally, a group of volatile compounds being the products of lipid oxidation are summarized. A short review of the formation, occurrence, and information on odor properties of all of these groups of compounds is given. Examples of SPME use for the analysis of compounds belonging to all described groups are shown. Elaboration of method parameters, fiber selection, experimental conditions, and quantitation of compounds are subjects of interest. Also, applications of SPME as a method for introduction of volatiles in mechanical olfaction technologies are shortly outlined.

An Accurate and Reproducible Method for the Quantitative Analysis of Isoflavones and Their Metabolites in Rat Plasma Using Liquid Chromatography/Mass Spectrometry Combined with Photodiode Array Detection

To study the safety and potential health benefits of soy isoflavones, a rapid and simple method based on liquid chromatography combined with mass spectrometry (LC/MS) and photodiode array detector (PDA) was developed for the determination of isoflavones in rat plasma. The analytes included daidzein, genistein, glycitein, equol, 4-ethyl phenol, and biochanin A over a concentration range of 1.0-4320.0 nM using 75 microL of rat plasma. Rat plasma samples were hydrolyzed by adding an enzyme mixture from Helix pomatia containing glucuronidase and sulfatase to convert the isoflavone beta-glycosides daidzin, genistin, and glycitin to their active aglycone forms. A liquid-liquid extraction method using ethyl acetate as the extraction solvent was used to extract aglycones and the internal standards (phenolphthalein beta-D glucuronide, 4-methylumbelliferyl sulfate, and apigenin) from digested plasma samples. The extract was evaporated to dryness under a nitrogen stream, reconstituted with 0.1% formic acid in water-acetonitrile (85 + 15), and injected into a Zorbax SB-CN reversed-phase column (4.6 x 75 mm, 3.5 microm particle size). The Micromass ZQ detector was operated in the positive ion selected-ion monitoring mode. The flow rate for LC was 1.0 mL/min, with a split where 25% of the effluent was introduced into the electrospray ionization probe of the MS instrument and 75% into the PDA. The chromatographic run time was 16.0 min, with delay of 10 min/injection. The interday precision and accuracy of the standard samples were <2.6% relative standard deviation and <10% relative error, respectively. Recovery of the reported isoflavones with this method varied from 86 to 100%.

Manure composition of swine as affected by dietary protein and cellulose concentrations1

An experiment was conducted to investigate the effects of reducing dietary CP and increasing dietary cellulose concentrations on manure DM, C, N, S, VFA, indole, and phenol concentrations. Twenty-two pigs (105 kg initial BW) were fed diets containing either 14.5 or 12.0% CP, in combination with either 2.5 or 8.7% cellulose. Pigs were fed twice daily over the 56-d study, with feed intake averaging 2.74 kg/d. Feces and urine were collected after each feeding and added to the manure storage containers. Manure storage containers were designed to provide a similar unit area per animal as found in industry (7,393 cm2). Before sampling on d 56, the manure was gently stirred to obtain a representative sample for subsequent analyses. An interaction of dietary CP and cellulose was observed for manure acetic acid concentration, in that decreasing CP lowered acetic acid in pigs fed standard levels of cellulose but increased acetic acid in pigs fed greater levels of cellulose (P = 0.03). No other interactions were noted. Decreasing dietary CP reduced manure pH (P = 0.01), NH4 (P = 0.01), isovaleric acid (P = 0.06), phenol (P = 0.05), and 4-ethyl phenol (P = 0.02) concentrations. Increasing dietary cellulose decreased pH (P = 0.01) and NH4 (P = 0.07) concentration but increased manure C (P = 0.03), propionic acid (P = 0.01), butyric acid (P = 0.03), and cresol (P = 0.09) concentrations in the manure. Increasing dietary cellulose also increased manure DM (P = 0.11), N (P = 0.11), and C (P = 0.02) contents as a percentage of nutrient intake. Neither cellulose nor CP level of the diet affected manure S composition or output as a percentage of S intake. Headspace N2O concentration was increased by decreasing dietary CP (P = 0.03) or by increasing dietary cellulose (P = 0.05). Neither dietary CP nor cellulose affected headspace concentration of CH4. This study demonstrates that diets differing in CP and cellulose content can significantly impact manure composition and concentrations of VFA, phenol, and indole, and headspace concentrations of N(2)O, which may thereby affect the environmental impact of livestock production on soil, air, and water.

Microstructure evolution in aqueous solutions of cetyl trimethylammonium bromide (CTAB) and phenol derivatives

Surfactant aggregate microstructure changes induced by the addition of a series of phenolic organic dopants (phenol, cresol, 4-ethyl phenol and 4- n- and i-butyl phenol) to a micellar solution of cetyl trimethyl ammonium bromide (CTAB) have been studied using cryogenic transmission electron microscopy (cryo-TEM). As the concentration of each of the dopants is increased, there is a systematic reduction in the curvature of the observed microstructures. For phenol and cresol the microstructure changes from globular micelles to rod-like micelles and then to long worm-like micelles. For 4-ethyl phenol and 4-butyl phenol, the microstructure transforms from globular micelles to worm-like micelles to unilamellar vesicles and then bilamellar vesicles. The concentrations at which these morphological transitions take place reduce as the number of methyl substitutions on the phenolic ring is increased. These microstructure transitions are attributed to changes in the packing parameter of the surfactant complex as dopants penetrate to different degrees in the surfactant palisades layer, resulting from a balance of interaction between the surfactant tails and the dopant aromatic chain and the hydrogen bonding of the hydroxyl group with surrounding water. The alignment of the hydroxyl dipoles reduces the electrostatic field around the CTAB head groups, decreases interlayer repulsive interactions and allows membrane fluctuations to stabilize the bilamellar vesicles. These highly tunable microstructures can be exploited for templated materials synthesis, and have implications for the micellar-enhanced ultrafiltration process.

Phytoestrogen metabolites are much more active than phytoestrogens themselves in increasing prostaglandin F 2α synthesis via prostaglanin F 2α synthase-like 2 stimulation in bovine endometrium

Phytoestrogens have recently been suggested to be the cause of infertility by stimulating luteolytic prostaglandin (PG) F 2α secretion from endometrium in cattle. The purpose of this study was to examine the enzymatic and molecular mechanisms involved in the preferential induction of PGF 2α synthesis by phytoestrogens, and whether phytoestrogens influence endometrial cell viability. Cultured bovine endometrial epithelial and stromal cells were exposed to phytoestrogens (daidzein and genistein) and their metabolites (equol and p-ethyl phenol) for 24 h. Prostaglandin F 2α and PGE 2 were stimulated by phytoestrogens in both stromal and epithelial cells, with a preference for PGF 2α synthesis in epithelial cells ( P < 0.001). Although RT-PCR and Western Blot analyses did not reveal the influence of phytoestrogens on either gene expression or protein level of cyclooxygenase-2 (COX-2) and PGE 2 synthase (PGES) in stromal and epithelial cells ( P > 0.05), the stimulative effects of equol and p-ethyl phenol on PGF 2α synthase-like 2 (PGFSL2) gene expression and protein level were observed only in epithelial cells ( P < 0.05). The same compounds did not affect PGFSL2 gene expression and protein in stromal cells ( P > 0.05). Exposure to phytoestrogens and their metabolites decreased cell viability in both stromal and epithelial cells. Stromal cell viability decreased to 50% of the control and was more evident than that in epithelial cells ( P < 0.001). The overall results suggest that infertility in cattle, caused by phytoestrogen-dependent preferential stimulation of luteolytic PGF 2α synthesis, is caused by increasing PGFSL2 in epithelial cells, and by decreasing stromal cell viability, which are the main source of luteotropic PGE 2 production.

Concurrent Phenomena Contributing to the Formation of the Aroma of Wine during Aging in Oak Wood: An Analytical Study

Red wine was stored in different oak barrels or in stainless steel, and samples were taken for two years to determine 79 aroma compounds. Aging in oak affects 41 compounds. The type of wood affects 11 compounds. At least seven different processes seem to take place concurrently in aroma evolution, and five such processes, affecting 37 compounds, are linked to the oak cask. These are extraction from the wood, oxidation of wine alcohols and amino acids, microbiological formation of ethyl phenols, sorption processes, and condensation of acetaldehyde with polyphenols. The wood can release linear gamma- and delta-lactones, beta-damascenone, and ionones. Some compounds are released very fast from wood, which suggests they lie in the external part of the wood. Some extraction profiles are too complex to be explained by physical processes. Finally, the levels of 2,5-dimethyl-4-hydroxy-3(2H)-furanone and 2-ethyl-5-methyl-4-hydroxy-3(2H)-furanone increase even in the reference wine, which suggests the presence of a precursor.

Soybean-Derived Phytoestrogens Regulate Prostaglandin Secretion in Endometrium During Cattle Estrous Cycle and Early Pregnancy

Phytoestrogens acting as endocrine disruptors may induce various pathologies in the female reproductive tract. The purpose of this study was to determine whether phytoestrogens present in the soybean and/or their metabolites are detectable in the plasma of cows fed a diet rich in soy and whether these phytoestrogens influence reproductive efficiency and prostaglandin (PG) synthesis during the estrous cycle and early pregnancy in the bovine endometrium. In in vivo Experiment 1, we found significant levels of daidzein and genistein in the fodder and their metabolites (equol and p-ethyl-phenol) in bovine serum and urine. The mean number of artificial inseminations (AIs) and pregnancy rates in two kinds of herds, control and experimental (cows fed with soybean 2.5 kg/day), were almost double in the soy-diet herd in comparison with the control animals. In in vivo Experiment 2, three out of five heifers fed soybean (2.5 kg/day) became pregnant whereas four out of five heifers in the control group became pregnant. The concentrations of a metabolite of PGF2alpha (PGFM) were significantly higher in the blood plasma of heifers fed a diet rich in soybean than those in the control heifers throughout the first 21 days after ovulation and AI. The higher levels of PGFM were positively correlated with equol and p-ethyl phenol concentrations in the blood. In in vitro experiments, the influence of isoflavones on PG secretion in different stages of the estrous cycle was studied. Although all phytoestrogens augmented the output of both PGs throughout the estrous cycle, equol and p-ethyl-phenol preferentially stimulated PGF2alpha output. The results obtained lead to the conclusion that soy-derived phytoestrogens and their metabolites disrupt reproductive efficiency and uterus function by modulating the ratio of PGF2alpha to PGE2, which leads to high, nonphysiological production of luteolytic PGF2alpha in cattle during the estrous cycle and early pregnancy.

Main compounds responsible for off-odour of strawberries infected by Phytophthora cactorum

Volatile compounds present in strawberries infected with Phytophthora cactorum, especially those responsible for the characteristic off-odour of such fruits were the subject of this study. Six strawberry varieties (Redgauntlet, Selva, Korona, Tenira, Real, Pegasus) inoculated with P. cactorum strain (PC-5), isolated from naturally infected fruit and one variety inoculated with 15 strains of P. cactorum in the laboratory were analysed. All the samples had a distinct, to a various degree, off-odour reminiscent of watercolour paint with phenolic notes. Volatile compounds were isolated by solid phase microextraction and simultaneous distillation extraction methods. To detect compounds responsible for the characteristic off-odour, gas chromatography-olfactometry was used. Two compounds were found to be responsible for the characteristic off-odour of strawberries infected by P. cactorum: 4-ethyl phenol and 4-ethyl-2-metoxy phenol (4-ethyl guaiacol). The content of these compounds in infected varieties ranged from 1.12 to 22.56 mg kg(-1) and 0.14-1.05 mg kg(-1) respectively. Other volatile compounds, not detected in noninoculated sound strawberries, were also identified: camphene, 1-octene-3-ol, 3-octanone, o-cymene, phenyl methanol, cis-linaloloxide, nonanal, phenyl ethyl alcohol, 2-undecanone and alpha-muurolene. Volatile compounds responsible for the characteristic off-odour of strawberries infected with P. cactorum were identified. Also compounds produced as a result of P. cactorum growth on strawberry fruit were characterized.

3-Ethyl-2,7-dimethyl octane, a testosterone dependent unique urinary sex pheromone in male mouse ( Mus musculus)

A previous investigation revealed that urine from normal male mice contained five unique volatile constituents; namely: 3-cyclohexene-1-methanol (I); 3-amino triazole (II); 4-ethyl phenol (III); 3-ethyl-2,7-dimethyl octane (IV); 1-iodoundecane (V). The present study was designed to find out whether the production of these male specific urinary compounds was androgen-dependent. Urine of castrated and castrated plus testosterone-treated male mice was analyzed using gas chromatography linked mass spectrometry (GC–MS). Even though castrated male urine contained 10 detectable compounds, the five male specific compounds present in intact males were absent in castrated male mice urine. Only 3-ethyl-2,7-dimethyl octane (IV) reappeared following testosterone treatment into castrated males. Our earlier bioassay revealed that this compound was involved in attracting females. The present study concluded that this compound was a male specific volatile cue that acted as a releaser pheromone and its production was under the control of androgen.

Para-selective ethylation of phenol with diethyl carbonate over mesoporous Al-MCM-41 molecular sieves

Mesoporous aluminosilicate Al-MCM-41 with Si/Al=33, 52, 75, and 114 were synthesized using cetyltrimethylammonium bromide (CTAB) as the structuring agent. The materials were characterized using several techniques. The mesoporous structure was confirmed by X-ray diffraction (XRD) technique. The surface area, pore size and pore volume were given by BET equation and BJH method using nitrogen sorption technique. Fourier transform-infrared (FT-IR) spectroscopy was used in order to obtain information on incorporated aluminum atoms in the mesoporous structure of Al-MCM-41. Silicon magic angle spin NMR ( 29Si-MAS NMR) was used to determine the types of silicon present in the mesoporous material. Aluminum magic angle spin NMR ( 27Al-MAS NMR) was used to determine the octahedral and tetrahedral coordination present in the Al-MCM-41. Thermogravimetric analysis–differential thermogravimetry (TGA–DTG) was used to determine the thermal stability of the materials. The effect of reaction temperature, WHSV and phenol:diethyl carbonate ratios on the selectivity of p-ethyl phenol were studied. The study of time on stream has been carried out to compare the activity of the catalysts and the results are discussed. The Al-MCM-41 (33) exhibited excellent selectivity for p-ethyl phenol obtained on ethylation of phenol using diethylcarbonate as the ethylating agent.

Gas chromatography-olfactometry and chemical quantitative study of the aroma of six premium quality spanish aged red wines.

The aroma of six premium quality Spanish red wines has been studied by quantitative gas chromatography-olfactometry (GC-O) and techniques of quantitative chemical analysis. The GC-O study revealed the presence of 85 aromatic notes in which 78 odorants were identified, two of which-1-nonen-3-one (temptatively) and 2-acetylpyrazine-are reported in wine for the first time. Forty out of the 82 quantified odorants may be present at concentrations above their odor threshold. The components with the greatest capacity to introduce differences between these wines are ethyl phenols produced by Brettanomyces yeasts (4-ethylphenol, 4-ethyl-2-methoxyphenol, and 4-propyl-2-methoxyphenol), 2,5-dimethyl-4-hydroxy-3(2H)-furanone (furaneol), (Z)-3-hexenol, thiols derived from cysteinic precursors (4-methyl-4-mercaptopentan-2-one, 3-mercaptohexyl acetate, and 3-mercaptohexanol), some components yielded by the wood [(E)-isoeugenol, 4-allyl-2-methoxyphenol, vanillin, 2-methoxyphenol (guaiacol), and (Z)-whiskylactone], and compounds related to the metabolism (2-phenylethanol, ethyl esters of isoacids, 3-methylbutyl acetate) or oxidative degradation of amino acids [phenylacetaldehyde and 4,5-dimethyl-3-hydroxy-2(5H)-furanone (sotolon)]. The correlation between the olfactometric intensities and the quantitative data is, in general, satisfactory if olfactometric differences between the samples are high. However, GC-O fails in detecting quantitative differences in those cases in which the olfactive intensity is very high or if odors elute in areas in which the odor chromatogram is too complex.

Characterization of urinary volatiles in Swiss male mice (Mus musculus): bioassay of identified compounds.

The present study was carried out to investigate the chemical nature of the urine of male mice and to assess its bioactivity. Urine of mature male mice was extracted with dichloromethane (1 : 1 ratio v/v) and analysed by gas-chromatography linked mass-spectrometry (GC-MS). Ten different compounds such as alkanes, alcohols, etc. were detected in the urine. Among the ten, five compounds are specific to males namely, 3-cyclohexene-1-methanol (I), 3-amino-s-triazole (II), 4-ethyl phenol (III), 3-ethyl-2,7-dimethyl octane (IV) and 1-iodoundecane (V). The compound, 4-ethylphenol, has been previously reported in several strains of male mice. Furthermore, the compounds (II) and (IV) are closely similar to 2-sec-butylthiazole and dehydro-exo-brevicomin compounds which have already been reported in male mice. Bioassay revealed that compounds (II), (III) and (IV) were responsible for attracting females and in inducing aggression towards males, as compared to the other compounds i.e. (I) and (V). The results indicate that these three volatiles (II, III and IV) of male mice appear to act as attractant of the opposite sex.

Seasonal variation in microbial communities and organic malodor indicator compound concentrations in various types of swine manure storage systems.

Anaerobic manure storage systems are one of the major contributors to the odor and environmental pollution associated with swine (Sus scrofa) production systems. The microbial ecology of manure storage systems and the relationships between microbial communities and odor production are largely unknown. In this study, we used community fatty acid methyl ester (FAME) analysis to generate lipid profiles to assess seasonal differences among microbial communities inhabiting various types of outdoor swine manure storage systems. Concurrently, we measured manure concentrations of several malodor indicator compounds as well as pH, temperature, and solids content. Principal components analysis (PCA) showed that there are differences in FAME profiles among the swine manure storage systems examined and most of the variation was in the relative abundance of 18:0, 18:1omega7t, 18:1omega7c/omega9t/omega12t, and 16:1omega7t/i15:0 2OH FAMEs. The PCA of the FAME profiles revealed that the phototrophic systems were more similar to each other and that the nonphototrophic systems were more similar to each other than they were to phototrophic lagoons. There were seasonal changes in the FAME profiles in the phototrophic systems and the concrete nonphototrophic basin (CNPB), and in one phototrophic system, the FAME profiles more closely resembled a CNPB FAME profile during the winter than the other phototrophic lagoons. In the phototrophic lagoon systems, there was a direct correlation between the abundance of the FAMEs identified in the PCA and manure concentrations of phenol, p-cresol, and 4-ethyl phenol. In the CNPB, there was a negative correlation between the total phenolics concentration and the 18:1omega7t FAME. Our results indicate that community FAME profiles could be used as a diagnostic tool for obtaining preliminary evidence that management practices are altering the system's microbial community to one that favors less air pollution potential.

Anaerobic digestion of olive oil mill effluents together with swine manure in UASB reactors

Combined anaerobic digestion of olive oil mill effluent (OME) with swine manure, was investigated. In batch experiments was shown that for anaerobic degradation of OME alone nitrogen addition was needed. A COD:N ratio in the range of 65:1 to 126:1 was necessary for the optimal degradation process. Furthermore, it was found that methane productions rates during digestion of either swine manure alone or OME alone were much lower than the rates achieved when OME and manure were digested together. Admixing OME with manure at a concentration of 5 to 10% OME resulted in the highest methane production rates. Using upflow anaerobic sludge blanket (UASB) reactors, it was shown that codigestion of OME with swine manure (up to 50% OME) was successful with a COD reduction up to 75%. The process was adapted for degradation of OME with stepwise increase of the OME load to the UASB reactor. The results showed that the high content of ammonia in swine manure, together with content of other nutrients, make it possible to degrade OME without addition of external alkalinity and without addition of external nitrogen source. Anaerobic treatment of OME in UASB reactors resulted in reduction of simple phenolic compounds such as mequinol, phenyl ethyl alcohol and ethyl methyl phenol. After anaerobic treatment the concentration of these compounds was reduced between 75 and 100%. However, the concentration of some degradation products such as methyl phenol and ethyl phenol were detected in significantly higher concentrations after treatment, indicating that the process has to be further optimised to achieve satisfactory removal of all xenobiotic compounds.