4-ethylphenol Research Articles

English

The microorganisms and compounds influencing the organoleptic properties of Ugba were studied. Ugba was produced by the fermentation of boiled and shredded seeds of African oil bean. The pure cultures of microorganisms responsible for Ugba fermentation were isolated from Ugba samples, produced by traditional method and were used in singles and in combination to ferment African oil bean shreds. The Ugba so fermented were analyzed organoleptically and sensory scores statistically analyzed using analysis of variance at P<0.5. Compounds in the samples of oil extracted from unfermented African oil bean shreds and Ugba samples fermented for 72 h with the microorganisms (in singles and in combinations) were analyzed by gas chromatograph. The result showed that the following microorganisms were involved in the fermentation of Ugba:Staphylococcus saprophyticus, Bacillus pumilus, Bacillus subtilis and Bacillus licheniformis. The organoleptic tests showed that in all parameters tested, the sample fermented by mixed starter culture of B. subtilis and B. licheniformis was generally liked, which implied ‘overall best’. Compounds found in unfermented Ugba were nineteen in number. Out of this number, eleven were found in unfermented samples, while eight were in the fermented Ugba. The best sample contained the following compounds: ethanol, ethyl stearate, ethyl oleate, ethyl linoteate, ethyl phenol and ethyl octanoate (their percentage concentration ranged from 2.69% for ethyl octanoate to 67.85% for ethanol). These compounds influenced the perceived Ugba flavor but had no direct influence on color and texture of Ugba sample. Key words: African oil bean seed, Ugba, fermentation, microorganisms, starter culture, organoleptic characteristics, flavor compounds.

Overview of Dekkera bruxellensis behaviour in an ethanol-rich environment using untargeted and targeted metabolomic approaches

Dekkera bruxellensis is a yeast known for its ability to produce ethyl phenols from hydroxycinnamic acid in wine, affecting the quality of its flavour. In wine, D. bruxellensis is not responsible for producing ethanol, however it is able to survive and sometimes also to grow in the presence of large amounts of ethanol. Because of its endurance, D. bruxellensis poses a serious threat to the wine industry and can cause substantial financial losses. In order to analyse yeast activity in the presence of different amounts of ethanol, the metabolic profile of a D. bruxellensis strain isolated from wine was outlined in defined chemical conditions in model wines. The metabolic profile of model wines with 10%, 11%, and 12% ethanol after D. bruxellensis growth was studied. Several ethyl esters and phenyl ethanol, together with 4-ethyl guaiacol, were produced in significantly higher amounts in response to the increase in ethanol stress. It was shown how the cell metabolism of specific compounds increased in response to a higher ethanol content, although yeast cell growth was limited.

Phenolic Biotransformations during Conversion of Ferulic Acid to Vanillin by Lactic Acid Bacteria

Vanillin is widely used as food additive and as a masking agent in various pharmaceutical formulations. Ferulic acid is an important precursor of vanillin that is available in abundance in cell walls of cereals like wheat, corn, and rice. Phenolic biotransformations can occur during growth of lactic acid bacteria (LAB), and their production can be made feasible using specialized LAB strains that have been reported to produce ferulic acid esterases. The present study aimed at screening a panel of LAB isolates for their ability to release phenolics from agrowaste materials like rice bran and their biotransformation to industrially important compounds such as ferulic acid, 4-ethyl phenol, vanillic acid, vanillin, and vanillyl alcohol. Bacterial isolates were evaluated using ferulic acid esterase, ferulic acid decarboxylase, and vanillin dehydrogenase assays. This work highlights the importance of lactic acid bacteria in phenolic biotransformations for the development of food grade flavours and additives.

Reduction of 4-ethylphenol production in red wines using HCDC+ yeasts and cinnamyl esterases

Hydroxycinnamate decarboxylase (HCDC) activity has been evaluated in several commercial yeast strains. The combined effect of using cinnamyl esterases (CE) and HCDC+ Saccharomyces cerevisiae strains has been studied in the formation of vinylphenolic pyranoanthocyanins (VPAs) during fermentation, analysing the kind and concentration of pigments formed according to the yeast strain used. Wines fermented with yeasts HCDC+ were contaminated with Dekkera bruxellensis and afterwards analysed to evaluate the formation of ethylphenols (EPs). The musts treated with CE and later fermented with HCDC+ yeast strains showed lower contents of 4-ethylphenol than those fermented with HCDC− strains. This reduction in the EP content is due to the transformation of hydroxycinnamic acids in stable VPAs pigments. The associated use of CEs and HCDC+ Saccharomyces strains is a natural strategy to reduce the formation of EPs in wines contaminated by Dekkera/Brettanomyces.

Aroma Chemical Composition of Red Wines from Different Price Categories and Its Relationship to Quality

The aroma chemical composition of three sets of Spanish red wines belonging to three different price categories was studied by using an array of gas chromatographic methods. Significant differences were found in the levels of 72 aroma compounds. Expensive wines are richest in wood-related compounds, ethyl phenols, cysteinil-derived mercaptans, volatile sulfur compounds, ethyl esters of branched acids, methional, and phenylacetaldehyde and are poorest in linear and branched fatty acids, fusel alcohols, terpenols, norisoprenoids, fusel alcohol acetates, and ethyl esters of the linear fatty acids; inexpensive wines show exactly the opposite profile, being richest in E-2-nonenal, E-2-hexenal, Z-3-hexenol, acetoin, and ethyl lactate. Satisfactory models relating quality to odorant composition could be built exclusively for expensive and medium-price wines but not for the lower-price sample set in which in-mouth attributes had to be included. The models for quality reveal a common structure, but they are characteristic of a given sample set.

Sinalbin degradation products in mild yellow mustard paste

Sinalbin degradation products in mild yellow mustard paste were investigated. The analyzed material consisted of a mild yellow mustard paste condiment and ground white mustard seeds which were originally used in the mustard paste production process. The samples were extracted in a Soxhlet extraction system and analyzed by gas chromatography - mass spectrometry (GC-MS) technique. The only sinalbin degradation product in ground mustard seeds was 2-(4-hydroxyphenyl)acetonitrile. The most abundant sinalbin degradation product in yellow mustard paste was 4-(hydroxymethyl)phenol. Other compounds identified in this sample were: 4-methyl phenol, 4-ethyl phenol, 4-(2-hydroxyethyl)phenol and 2-(4-hydroxyphenyl) ethanoic acid.

Odor and Odorous Chemical Emissions from Animal Buildings: Part 4. Correlations Between Sensory and Chemical Measurements

This study supplemented the National Air Emissions Monitoring Study (NAEMS) with one year of comprehensive measurements of odor emission at five swine and four dairy buildings. The measurements included both standard human sensory measurements using dynamic forced-choice olfactometry and chemical analysis of the odorous compounds using gas chromatography-mass spectrometry. In this article, multilinear regressions between odor and gas concentrations (a total of 20 compounds including H2S, NH3, and VOCs) were investigated. Regressions between odor and gas emission rates were also tested. It was found that gas concentrations, rather than emission rates, should be used to develop multilinear regression models. For the dairy sites, H2S, NH3, acetic acid, propanoic acid, 2-methyl propanoic, and pentanoic acids were observed to be the compounds with the most significant effect on sensory odor. For the swine sites, in addition to these gases, higher molecular weight compounds such as phenol, 4-methyl phenol, 4-ethyl phenol, and 1H-indole were also observed to be significant predictors of sensory odor. When all VOCs were excluded from the model, significant correlations between odor and H2S and NH3 concentrations were still observed. Although these coefficients of determination were lower when only H2S and NH3 were used, they can be used to predict odor variability by up to 83% when VOC data are unavailable.

Tobacco and cigarette butt consumption in humans and animals

Discarded cigarette butts may present health risks to human infants and animals because of indiscriminate eating behaviours. Nicotine found in cigarette butts may cause vomiting and neurological toxicity; leachates of...

Kluyveromyces wickerhamii killer toxin: purification and activity towards Brettanomyces/Dekkera yeasts in grape must

Brettanomyces/Dekkera yeasts have been identified as part of the grape yeast flora. They are well known for colonizing the cellar environmental and spoiling wines, causing haze, turbidity and strong off-flavours in wines and enhancing the volatile acidity. As the general practices applied to combat Brettanomyces/Dekkera yeasts are not particularly appropriate during wine ageing and storage, a biological alternative to curtailing their growth would be welcomed in winemaking. In this study, we investigated the Kluyveromyces wickerhamii killer toxin (Kwkt) that is active against Brettanomyces/Dekkera spoilage yeasts. Purification procedures allowed the identification of Kwkt as a protein with an apparent molecular mass of 72 kDa and without any glycosyl residue. Interestingly, purified Kwkt has fungicidal effects at low concentrations under the physicochemical conditions of winemaking. The addition of 40 and 80 mg L(-1) purified Kwkt showed efficient antispoilage effects, controlling both growth and metabolic activity of sensitive spoilage yeasts. At these two killer toxin concentrations, compounds known to contribute to the 'Brett' character of wines, such as ethyl phenols, were not produced. Thus, purified Kwkt appears to be a suitable biological strategy to control Brettanomyces/Dekkera yeasts during fermentation, wine ageing and storage.

Urine-Derived Key Volatiles May Signal Genetic Relatedness in Male Rats

Olfactory cues play a vital role in kin recognition and mate choice of the rat. Here, using 2 inbred strains of rats, Brown Norway (BN) and Lewis, as models to simulate kinship via genetic distance, we examined whether urine-derived volatiles are genetically determined, and, if so, how they code for olfactory information and the degree of genetic relatedness in mate choice. Binary choice tests showed that BN females preferred the urine odor of Lewis males over that of BN males, suggesting that they avoided males genetically similar to themselves and were able to assess this olfactorily. Gas chromatography-mass spectrometry analysis revealed that the composition of urine-derived volatiles was more similar within strains than between strains and suggests that odortypes may reflect genetic relatedness. Our data further show that BN males had lower ratios of 2-heptanone and 4-heptanone and higher ratios of dimethyl sulfone and 4-ethyl phenol than Lewis males. When we supplemented BN and Lewis male urine to make each similar, the preferences of BN females were reversed. We conclude that some urine-derived volatiles covary in relative abundance with degree of genetic relatedness, and this relationship may play a key role in chemical signaling and genetic identity in this species.

IDENTIFIKASI PRODUK TURUNAN HYDROPROCESSING MODEL MINYAK SINTETIS BATUBARA MENGGUNAKAN GC-FID/NPD/MS

An analysis of identifying a derivative product of liquefied coal modelhydroprocessing was conducted. For that purpose, an integration gaschromatography flame ionization-nitrogen phosphorous detector and massspectrometry (GC-FID/NPD/MS) was used. Hydroprocessing process wasperformed by vibrating micro autoclave tipe batch using Ni-W/Alumina catalystunder initial hydrogen pressure 6 MPa, reaction temperature 375oC and one hourretention time. The analysis result showed that the predominant reaction werehydrogenation, hydrodenitrogenation (HDN) and hydrodeoxygenation (HDO).The HDO of methyl phenol and ethyl phenol took place faster than the otherhydroprocessing reactions such as HDN of quinoline and aromatic hydrogenation(butyl benzene, naphthalene, phenanthrene dan pyrene). This indicates that thehydrogenation reaction or the cleavage of C-O bonding took place very fast thatalkyl could not be detected in the oil. The HDN reaction or the cleavage of C-Ntook place slower but the the nitrogen containing compound vanished faster dueto selective adsorption of the catalyst. However the hydrogenation reaction ofmono-aromatic took place faster than poly-aromaticKata kunci: gas chromatography, identifikasi senyawa, model minyak sintetis

Pilot Scale Facility to Determine Gaseous Emissions from Livestock Slurry during Storage

Livestock production is a growing source of air pollution, locally and to the wider environment. Improved livestock manure management has the potential to reduce environmental impacts, but there is a need for methodologies to precisely quantify emissions. This paper describes and evaluates a novel storage facility for livestock slurry consisting of eight 6.5-m(3) cylindrical units. The stores may be equipped with airtight covers and ventilated during storage or during measurement only. Each store has eight air inlets (160 mm diameter) and a single outlet in the cover connected to a main ventilation duct. The stores can also be used as static enclosures. Ventilation can be regulated within the range of 50 to 250 m(3) h(-1). A gas sampling line enables sampling of odorants using automatic thermal desorption tubes, ammonia using acid traps, and greenhouse gases using gas sampling bags (pooled samples) or a syringe (time point samples). Complete recovery of CH(4) independent of ventilation rate was demonstrated. Vertical profiles of CO(2) and CH(4) above the slurry surface with and without ventilation and mixing of the headspace indicated methane oxidation activity in the surface crust. p-Cresol and 4-ethyl phenol emission from pig slurry was identified by GC-MS analysis of odor collected on adsorption tubes. Ammonia emissions between 0 and 166 mg N m(-2) h(-1) were observed during storage of pig slurry with and without surface crust and cover. A comparison of pooled and averaged time point measurements of CO(2), CH(4), and N(2)O indicated that pooled samples account for the diurnal variations under realistic storage conditions.

Influence of Serving Temperature and Wine Type on Perception of Ethyl Acetate and 4-ethyl Phenol in Wine

This research explored the effect of temperature on the perception of two chemical compounds (ethyl acetate, 4-ethyl phenol) in four base wines (Gewurztraminer, Chardonnay, white blend, red blend). The perceived aroma intensity was evaluated at three serving temperatures (5°C, 10°C, 22°C) with wines which were spiked with 200 ppm ethyl acetate and 1000 ppm 4-ethyl phenol, using a panel of eight judges. Special attention was paid to the insulation of the wine glasses to maintain the temperature of the wine samples. The panel was required to wear wool scarves and gloves to eliminate cognitive and physical clues. The relationships between temperature and perceived intensity for fruit, ethyl acetate and 4-ethyl phenol were between 0.951 and 0.991, with all base wines. The perception of ethyl acetate was most noticeable in the neutral wines (white, red blends) and least noticeable in the highly aromatic Gewurztraminer and Chardonnay wines at 20°C. In contrast, 4-ethyl phenol was least noticeable at 20°C in the wines with greater phenolic constituents, Chardonnay and the red blend. The chemical 4-ethyl phenol appeared to suppress the perception of fruit in all base wines at all temperatures.

Sorption of volatile phenols by yeast cell walls

Yeast walls can retain different wine compounds and so its use is interesting in order to eliminate harmful substances from the must which affect alcoholic fermentation (medium chain fatty acids) or which affect wine quality in a negative way (ethyl phenols, ochratoxin A). The aim of this study was to examine the capacity of commercial yeast cell walls in eliminating volatile phenols (4-ethylphenol and 4-ethylguaiacol) from a synthetic wine that contained 1 mg/L of each one of these compounds. The binding of these compounds to the wall was quite fast which would seem to indicate that the yeast wall-volatile compound union is produced in the outer surface layers of this enological additive. The cell walls used reduced the concentration of 4-ethylphenol and 4-ethylguaiacol, although it would seem that on modifying the matrix of the wine the number of free binding sites on the walls is also modified.

An infrared spectroscopic study of hydrogen bonding in ethyl phenol: A model system for polymer phenolics

A detailed analysis of the bands appearing in the OH stretching region of the infrared spectrum of ethyl phenol solutions is presented. In cyclohexane solutions, the band due to “free” (non-hydrogen-bonded groups) contains overlapping contributions from both monomeric and end-group species. Other assignments are made on the basis of whether the proton and oxygen in a particular OH group are both involved in hydrogen bonds (as “donors” and “acceptors”, respectively), or if only the proton is acting as a donor. The strongest band in the spectra obtained at the highest concentration of ethyl phenol is due to OH groups present in linear chains of hydrogen-bonded OH groups (as recognized in numerous other studies), but a band due to cyclic trimers has also been identified. The assignment of other modes is more uncertain and various possibilities are discussed. In toluene solutions, assignments are more complicated, because bands due to OH–π hydrogen bonds are observed instead of free groups. Finally, the data from cyclohexane solutions was used to calculate equilibrium constants capable of describing the distribution of species present. A new methodology for determining the equilibrium constant describing association in the form of dimers is described.

Simple and Sensitive Determination of 2,4-Xylenol in Surface Water Samples from River and Sea by Gas Chromatography–Mass Spectrometry

A simple and selective method was developed for determination of the concentration of 2,4-xylenol in river and sea water samples using gas chromatography/mass spectrometry (GC/MS). Trace amounts of 2,4-xylenol were collected in a Oasis HLB Plus cartridge, eluted with acetonitrile. The method detection limit of 2,4-xylenol was 1.4 ng/L. The trace peaks of 2,4-xylenol were found in water samples from the river and the sea, and the concentrations were all less than 1.4 ng/L. The nine peaks of the 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-xylenol, and o-, m-, p-ethyl phenol that gave the same m/z ratio were separated efficiently.

Odour and ammonia emission from pig manure as affected by dietary crude protein level

The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, odour hedonic tone, ammonia and greenhouse gaseous emission from pig manure, and on fresh faeces and manure characteristics. An experiment was conducted with finishing pigs ( n = 12) in a randomized complete block arrangement with 2 treatments of 12 and 15% dietary CP in six blocks. The 2 diets were supplemented with essential AA up to the level of the animal's requirement. Pigs with an initial body weight (BW) of 57.7 ± 0.7 kg were penned individually in partly slatted floor pens. Faeces and urine of each pig accumulated in separate manure pits under the slatted floor. In the 3rd week of the collection period, fresh faeces were collected for identifying fresh faeces characteristics and for assessing dry matter, organic matter, nitrogen (N), fat and non-starch polysaccharides digestibility using Cr 2O 3 as a marker. In the 6th week of the collection period, air samples were collected directly from each manure pit: one for odour, one for ammonia concentration and one for greenhouse gases. Afterwards the manure was mixed and a representative sample was taken for manure characteristic analysis. Odour samples were analyzed for odour concentration and for hedonic tone and odour intensity. Manure samples were analyzed for volatile fatty acids (VFA), indolic, phenolic, sulphurous compounds, ammonium and total N concentrations and pH. Reducing dietary CP level from 15 to 12% did not affect odour emission, odour intensity and odour hedonic tone and greenhouse gaseous concentration (CH 4, CO 2 and N 2O) ( P > 0.05) of odorous air above the manure pit. Reduced dietary CP level decreased manure pH ( P < 0.001), total N ( P < 0.001) and ammonium ( P < 0.001) concentrations and ammonia emission from pig manure ( P = 0.03). In addition, total VFA, acetic, propionic, iso-butanoic and iso-pentanoic acids, phenol, 4-ethyl phenol and carbon disulfide concentrations in manure were decreased by reducing dietary CP level ( P < 0.05). We conclude that reducing dietary CP from 15 to 12% did not reduce odour emission and greenhouse gaseous concentration; however, ammonia emission was significantly reduced.

Miscibility and Hydrogen-Bonding Behavior in Organic/Inorganic Polymer Hybrids Containing Octaphenol Polyhedral Oligomeric Silsesquioxane

In this study, we investigated the miscibility behavior and mechanism of interaction of poly(methyl mechacrylate) (PMMA), poly(vinyl pyrrolidone) PVP, and PMMA- co-PVP blends with octa(phenol)octasilsequioxane (OP-POSS). For the PMMA/OP-POSS binary blend, the value of the association constant ( K A = 29) was smaller than that in the poly(vinyl phenol) (PVPh)/PMMA ( K A = 37.4) and ethyl phenol (EPh)/PMMA ( K A = 101) blend systems, implying that the phenol groups of the OP-POSS units in the PMMA/OP-POSS blends interacted to a lesser degree with the CO groups of PMMA than they did in the other two systems. In addition, the ionic conductivity of a LiClO4/PMMA- co-PVP polymer electrolyte was increased after blending with OP-POSS.

Sex- and Gonad-Affecting Scent Compounds and 3 Male Pheromones in the Rat

This study was aimed at identifying sex pheromones of the rat (Rattus norvegicus). We characterized the volatiles and semivolatiles of rat preputial gland and voided urine by using gas chromatography–mass spectrometry (GC–MS) and quantified them by their GC areas (abundances) and percentage of GC areas (relative abundances). Although all the compounds other than 4-heptanone and phenol detected were shared by males and females, the quantities for some of these sex-common compounds exhibited sexual dimorphism and decreased with gonadectomy. Thus, these compounds might be sex pheromones. Among them, squalene from preputial glands and 2-heptanone and 4-ethyl phenol from urine were 3 major compounds. They were richer in males and could be suppressed by castration. Adding any of the 3 compounds (at a concentration higher than its physiological level in male urine) to castrated male urine (CMU) increased the attractiveness of CMU to sex-naive females. Adding the 3 together (at the levels in normal male urine) to CMU significantly increased the attractiveness of CMU to females. However, such combination did not fully restore females' preference for urine from intact males, suggesting that some other trace compounds such as 4-heptanone and phenol might also play some roles in sex attractiveness. Thus, squalene, 2-heptanone, and 4-ethyl phenol were indeed male pheromone molecules in rats. Our study also indicates that E,E-β-farnesene and E-α-farnesene, both richer in females than males, might be putative female pheromones.

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.