Isolation and characterization of Streptomyces sp. NL15-2K capable of degrading lignin-related aromatic compounds

Strain NL15-2K was isolated from soil by screening for bacteria capable of catabolizing lignin-related aromatic acids. This isolate was identified as a Streptomyces sp. on the basis of morphology and an analysis of its 16S rRNA gene sequence. NL15-2K utilized caffeic acid, coniferyl alcohol, ferulic acid, isovanillic acid, protocatechuic acid, vanillic acid, vanillin, and veratric acid as sole carbon sources.     

Growth inhibition of tomato-rot fungi by phenolic acids and essential oil extracts of pepperfruit (Dennetia tripetala)

Phenolic and essential oil extracts of pepperfruit (Dennetia tripetala) showed antifungal activity against Saccharomyces cerevisiae, Saccharomyces sp., Candida tropicalis, Candida sp., Cryptococcus sp., Geotrichum sp., Rhizopus stolonifer, Aspergillus niger and Fusarium sp. isolated from spoilt tomato fruits and cultured on agar plates. Antifungal activity of phenolic and essential oil extracts was observed at inhibitory concentrations (IC) in the range of 2.5–6.5 and 1.5–3.0 mg/ml tomato/glucose medium respectively. Combination of phenolic and essential oil extracts at concentrations below IC values significantly retarded growth of fungi resident in blended freshly harvested and open market tomato fruits. These fungi were not detected in the tomato after 1 month storage when mild heat (80°C for 1 min) and NaCl (10 mg/g) were combined with the phenolic and essential oil extracts as preservative hurdles. The population of challenge fungi in blended tomato treated with the same low concentration of the extracts and salt but without heat hurdle, steadily declined till none was detected after 3 months. Being an edible fruit, pepperfruit extracts may prove a useful natural preservative in food processing.     

Volatile compounds produced by fungi grown in strawberry jam

Fungi are most important micro-organisms spoiling jams and other fruit preserves. The volatile compounds produced by fungi can be used to detect fungal growth in food. The aim of this study was to identify volatile organic compounds indicating fungal growth in strawberry jam. Ten fungal strains isolated from jam, yogurt or indoor air were grown in strawberry jam and strawberry jam agar. The volatile compounds produced by fungi were separated, identified and quantified using gas chromatography and mass spectrometry. The most commonly produced volatile metabolites were 2-pentanone (produced by ten strains), 3-methyl-1-butanol (nine strains), 1,3-pentadiene (eight strains), ethanol (eight strains) and styrene (seven strains). From 17 to 5200 ng of these compounds were measured per g of moldy strawberry jam agar already after 2 days incubation. The results indicate that volatile fungal metabolites identified in this study could be used to detect fungal contamination of jam.     

葡萄的芳香物质

芳香物质是葡萄果皮中的主要物质,存在于果皮的下表皮细胞中。但有的葡萄品种（如玫瑰香MUSCAT系列品种）的果肉中也含有芳香物质。各种葡萄品种特殊的果香味决定于它们所含有的芳香物质的种类。葡萄的香味对于每个品种是特定的,但其浓度和优雅度决定于品种的营养系、种植方式、年份、生态条件和浆果的成熟度。葡萄的芳香物质种类很多,以具有挥发性的游离态和不具挥发性的结合态,但可变为游离态的芳香物质两种形态存在。因此,只有游离态的芳香物质才具有气味。1 葡萄的游离态芳香物质这类物质包括能同时引起嗅觉和味觉的挥发性物质…     

茅台酱香型酒糟香气成分分析

采用水蒸气蒸馏法提取茅台酱香型酒糟的香气成分,并采用气相色谱-质谱法(GC-MS)对其分离和鉴定,鉴定出32种成分,其中糠醛、亚油酸乙酯、棕榈酸乙酯、油酸乙酯、5-甲基-2-糠醛、苯乙醇、吡咯-2-甲醛、苯甲醛、苯乙醛、2-乙酰呋喃、糠醇、2,3,5,6-四甲基吡嗪、9-十五碳烯酸乙酯、2-羟基-3-苯基丙酸乙酯、硬脂酸乙酯、3-乙酰基吡咯、植烷等是构成茅台酱香型酒糟香气的主要成分,占香气成分的93.9%。     

Binding of p-nitrophenyl phosphate and other aromatic compounds by beta-lactoglobulin

Results obtained from gel filtration showed that beta-lactoglobulin binds p-nitrophenyl phosphate with a stoichiometry of 1 mol of ligand per 18,360 monomer. Circular dichroic spectra confirmed the binding and implicated tryptophan and phenylalanine residues in the interaction. Fluorescence of the protein was quenched on binding also supporting complex formation; analysis of these data indicates that p-nitrophenyl phosphate binds to beta-lactoglobulin A with a dissociation constant of 31 microM. The B and C genetic variants of beta-lactoglobulin bind p-nitrophenyl phosphate with dissociation constants of 63 and 70 microM, respectively. In addition, a series of other nitrophenyl compounds and pyridoxal phosphate were also investigated by fluorescence analysis and found to bind to the protein. These results are discussed with respect to a recent hypothesis that beta-lactoglobulin binds retinol and is structurally related to serum retinol binding protein.     

Adsorption of aromatic compounds from water by treated carbon materials

Carbon materials with different textural and surface chemistry properties have been studied to analyze their behavior in removing aromatic compounds (phenol, o-chlorophenol, p-nitrophenol, aniline, and phenol compound mixtures) from water. A mesoporous high surface area graphite and a microporous activated carbon with (HSAGox and ACox) and without (HSAGT and ACT) oxygen surface groups, were used as adsorbents. Apparent surface areas, surface oxygen groups, and zero points of charge have been determined. The adsorption behavior of single compounds on ACT depends on the relation between the molecular and the pore sizes. The aniline, the nitrophenol, and the chlorophenol interact with the oxygen surface groups of oxidized graphite, while there is no evidence of any type of interaction of the phenol with these groups. The adsorption of the organic compound mixtures on the thermally treated samples is determined by the acid-base character of the adsorbate-adsorbent, whereas on the oxidized carbons, the controlling forces are the specific interactions between organic molecules and the oxygenated groups. Selectivity coefficients for the different mixtures are presented over the entire range of adsorption.     

Mycotoxicogenic fungal inhibition by innovative cheese cover with aromatic plants

BACKGROUND: The use of aromatic plants and their extracts with antimicrobial properties may be compromised in the case of cheese, as some type of fungal starter is needed during its production. Penicillium verrucosum is considered a common cheese spoiler. The aim of this study was to evaluate the innovative use of certain aromatic plants as natural cheese covers in order to prevent mycotoxicogenic fungal growth (P. verrucosum). A collection of 12 essential oils (EOs) was obtained from various aromatic plants by solvent‐free microwave extraction technology, and volatile characterisation of the EOs was carried out by gas chromatography/mass spectrometry. RESULTS: The most effective EOs against P. verrucosum were obtained from Anethum graveolens, Hyssopus officinalis and Chamaemelum nobile, yielding 50% inhibition of fungal growth at concentration values lower than 0.02 µL mL^?1. All EOs showed high volatile heterogeneity, with α‐phellandrene, pinocamphone, isopinocamphone, α‐pinene, camphene, 1,8‐cineole, carvacrol and trans‐anethole being found to be statistically significant in the antifungal model. CONCLUSION: The use of these aromatic plants as natural covers on cheese can satisfactorily inhibit the growth of some mycotoxicogenic fungal spoilers. Among the volatile compounds present, α‐ and β‐phellandrene were confirmed as the most relevant in the inhibition. © 2012 Society of Chemical Industry     

黄酒酒糟中的香气成分分析

采用微波萃取的方法,提取黄酒酒糟中的香气成分,经浓缩后,用GC-MS对其进行分离和鉴定,确认了58种组分,其中苯乙醇等13种成分是构成黄酒香气的主体成分,而其余的30多种微量成分及其特殊的构成比例是形成糟香的原因.     

Determination of phenolic compounds in aromatic plants by RP-HPLC and GC-MS

It is well known that phenolic compounds are constituents of many plants and herbs, and they have attracted a great deal of public and scientific interest because of their health-promoting effects as antioxidants. Five plants, Vitex agnus-castus (Verbenaceae), Origanum dictamnus (Lamiaceae), Teucrium polium (Lamiaceae), Lavandula vera (Lamiaceae) and Lippia triphylla (Verbenaceae), were examined in order to determine their phenolic composition. Reversed phase high performance liquid chromatography was employed for the identification and quantification of phenolic compounds. Gas chromatography–mass spectometry(GC-MS) was also used for identification of phenolic compounds after silylation. Analysis of the non-volatile and thermolabile phenolic compounds by GC-MS presupposes their conversion into volatile and thermotolerant derivatives. The derivatization process was optimized against reagents, temperature and reaction time. A large excess of N,O-bis(trimethylsilyl)trifluoroacetamide containing trimethylchlorosilane proved to be the best derivatization reagent to convert analytes into volatile trimethylsilyl derivatives. The most abundant phenolic compounds detected were caffeic acid (0.12–0.93 mg 100 g⁻¹ dry sample), ferulic acid (0.34–1.52 mg 100 g⁻¹ dry sample), and (+)-catechin (0.22–0.43 mg 100 g⁻¹ dry sample).     

Growth inhibition of foodborne pathogens by Oenococcus oeni

Abstract: To explore the possibility of using Oenococcus oeni to inhibit foodborne pathogens, and to characterize antimicrobial compounds produced by O. oeni, 24 strains of O. oeni were tested for their ability to inhibit growth of foodborne pathogens, Escherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes by using the spot‐on‐lawn method. Of the 24 strains, 17 strains were able to inhibit all 3 pathogens in this study. Proteases, catalase, and buffer solutions were used for determining the type of inhibitory compounds produced from 4 selected strains with stronger inhibitory activity. Antimicrobial activity of 2 strains against the pathogens was completely inactivated by buffer solution, and other 2 strains against E. coli O157:H7 were partially removed. The antimicrobial compound was not sensitive to selected proteases and catalase. Practical Application: There is little information available about using O. oeni for human pathogens control. The results of this study revealed such discovery and potential applications for pathogen control.     

Polycyclic aromatic compounds in curing smoke

The curing smoke, generated by the smouldering of alder chips, from a commercial food smoking plant was investigated with respect to polynuclear aromatic compounds (PAC). Samples were taken from inside the ovens and in the working zone immediately outside them. Analysis showed that considerable amounts of methyl phenanthrenes were present in the smoke as a major part of the PAC content.     

Polycyclic aromatic compounds in curing smoke

Summary The curing smoke, generated by the smouldering of alder chips, from a commercial food smoking plant was investigated with respect to polynuclear aromatic compounds (PAC). Samples were taken from inside the ovens and in the working zone immediately outside them. Analysis showed that considerable amounts of methyl phenanthrenes were present in the smoke as a major part of the PAC content.

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Polycyclische aromatische Verbindungen im Rauch einer Räucherei

Zusammenfassung Rauch aus einer kommerziellen Räucherei von schwelenden Erlenspänen wurde auf polycyclische aromatische Verbindungen (PAC) untersucht. Proben wurden innerhalb der Öfen und in dem Arbeitsbereich außerhalb der Öfen gezogen. Erhebliche Mengen an Methylphenanthren wurden als Hauptbestandteil des PAC-Inhalts im Rauch nachgewiesen.

     

Recovery of aroma compounds from Zhenjiang aromatic vinegar by supercritical fluid extraction

Zhenjiang aromatic vinegar, which is produced from sticky rice through solid‐state fermentation, is highly prized as one of the four famous China‐style vinegars, owing to its unique flavour. In this study, a method of supercritical fluid extraction (SFE) was used for the first time to recover aroma compounds from Zhenjiang aromatic vinegar. For this purpose, the optimal conditions for the extraction of aroma compounds by SFE were determined as follows: CO₂ flow rate, 25 L h^?1; extraction time, 2 h; extraction pressure, 35 MPa; and extraction temperature, 323 K. Using headspace solid‐phase microextraction‐gas chromatography–mass spectrometry (HS‐SPME‐GC‐MS) analysis, a total of 49 and 44 aroma compounds were identified in Zhenjiang aromatic vinegar and its SFE extract, respectively. Acetic acid, ethyl acetate, furfural, phenethyl alcohol, tetramethyl‐pyrazine, 3‐hydroxybutanone and benzaldehyde were the main aroma compounds in the vinegar and its SFE extract. SFE is a fast and sensitive method to recovery aroma compounds from the vinegar.     

Sorption and manganese-induced oxidative coupling of hydroxylated aromatic compounds by natural geosorbents

The sorption/desorption equilibria and solvent extractabilities of phenol, o-cresol, and p-chlorophenol with respect to natural sorbents having different types of soil organic matter were investigated. Parallel tests in systems amended with birnessite (delta-MnO2), a solid-phase oxidative coupling catalyst, were also conducted. Sorption/desorption isotherms and solvent extraction data reveal that the relative isotherm linearities, desorption hysteresis, and extractabilities of these compounds are related to the geochemical nature of the sorbent organic matter and to the existence of system conditions that promote oxidative coupling reactions. When suitable coupling catalysts are present, soils containing primarily diagenetically "young" and highly amorphous organic matter (e.g., humic materials) are more likely to retain those solutes than are those containing primarily diagenetically "old" and more condensed organic matter (e.g., kerogens). The sorption/desorption properties of the solutes were significantly altered in the presence of birnessite as a result of both cross-coupling reactions with reactive soil organic matter components and self-coupling reactions with each other to form polymeric species. Under appropriate conditions, mineral-catalyzed oxidative coupling may exert a dominant influence on the sorption and transport of hydroxylated aromatic compounds in soil and sediment systems.     

威代尔冰葡萄酒香气测定

采用GC-MS法分析研究威代尔(Vidal)冰葡萄酒中的香气成分。以我国辽宁本溪地区的威代尔冰葡萄酒为试材,采用HS-SPME法提取冰葡萄酒中的香气,并进行GC-MS定性分析,在威代尔冰葡萄酒香气中分离到101种挥发性成分,定性出59种,其中主要包括酯类、醇类、酸类和呋喃类芳香成分。     

Investigation of aromatic compounds in roasted cocoa powder

Most of the volatile compounds identified are highly significant in determining cocoa powder flavour, and this paper demonstrates that basic sensory perceptions (undesirable, bitter pungent, repulsive, fruity, nutty, floral, vegetal, and sweet chocolate) can be totally explained by aroma compounds with R²-adjusted values of 0.85 and greater. Samples from five geographical origins of cocoa bean were characterized by chemical compounds and sensory attributes. The aroma extracts were obtained by a two-step procedure involving (1) preliminary steam distillation under reduced pressure to evaluate the methylpyrazines generated in roasted cocoa powder by spectrophotometry (flavour index), and (2) Likens-Nickersons simultaneous steam distillation and solvent extraction method with added NaCl. The distilled compounds were separated by adsorption chromatography in six fractions depending on the polarity. A combined total of 114 compounds were detected by gas chromatography/mass spectrometry, 110 of which were identified. About 15 components in the mean milligrams per kilogram range (1.09–4.67 mg kg^–1) and 95 components in the mean micrograms per kilogram range (12–980 µg kg^–1) were quantified. The major components of cocoa aroma were 2,3,5,6-tetramethylpyrazine, benzaldehyde, 2-phenylacetaldehyde, acetophenone, 3-methylbutyric acid, 5-methyl-2-phenyl-2-hexenal, ethyl phenylacetate, and 3-hydroxy-2-methyl-4-pyrone (mean greater than 1.30 mg kg^–1).     

Biocatalytic synthesis of polycatechols from toxic aromatic compounds

A process is described in which toxic aromatic compounds are converted by toluene dioxygenase and in turn toluene cis-dihydrodiol dehydrogenase to catechols which are further polymerized by peroxidase-catalyzed oxidation producing polycatechols. Three approaches for obtaining catechols were employed: (1) addition of halogenated aromatics to P. putida F1, resulting in the accumulation of halogenated catechols; (2) inhibition of catechol 2,3-dioxygenase of P. putida F1 by known aromatic and aliphatic inhibitors; and (3) overexpression of toluene dioxygenase and toluene cis-dihydrodiol dehydrogenase genes in E. coli JM109. The process is suitable for producing novel catechols that upon oxidation may yield polymers with unique properties, presenting a tool for producing tailor-made biopolymers. Formation of 3-chlorocatechol from chlorobenzene, 3,4-dichlorocatechol from 1,2-dichlorobenzene, and catechol from benzene and their subsequent oxidation and polymerization was demonstrated. Oxidation of catechol yielded polymers with molecular weights of up to 4000 Daltons. Their apparently high water solubility eliminates the need for water-miscible solvents. In aqueous solution oxidation of catechols was rapid, yet the presence of 20%, 30%, and 40% ethanol, resulted in a rate decrease of 31%, 95%, and 93%, respectively. The advantage is that significantly less peroxidase is required for performing the reactions if miscible solvents are not employed. Furthermore, water-soluble polymers may be desirable for many applications.     

白兰地挥发性芳香族化合物的初步探究

香气成分是评判白兰地酒品质的一个重要感官指标,而芳香族化合物是各种蒸馏酒的重要香气组分。该文收集了已检测到的72种白兰地中挥发性芳香族化合物,描述了其的香气特征,并简述了重要芳香族化合物的的来源及形成机理。     

Characterization of aromatic compounds and biological activities of essential oils from Tunisian aromatic plants

The aromatic compounds and biological activities of essential oils from six Tunisian aromatic plants including Artemisia herba-alba, Rosmarinus officinalis, Thymus capitatus, Mentha piperita, Ocimum basilicum and Artemisia absinthium were investigated. Hydro-distillation was used to extract essential oil from these plants. The identification of compounds from essential oils was performed using GC–MS analysis. Camphor (28.47%) was the major compound of A. absinthium essential oil. High contents of verbenone (20.99%) and camphor (19.72%) were found in R. officinalis. In the case of T. capitatus, carvacrol (81.09%), gamma terpinene (6.61%) and caryophyllene (4.87%) were identified as the major compounds. While eugenol (24.69%), linalool (18.00%) were characteristic compounds of O. basilicum essential oil, camphor (39.10%) and farnesol (14.25%) together with bornyl acetate (12.31%) were the main constituents of A. absinthium. These oils were also subjected to a screening for their antioxidant activity and essential oil from A. absinthium showed a greater antioxidant activity (IC₅₀?=?0.0063 mg/mL) compared to the standard Vitamin E (IC₅₀?=?0.019 mg/mL). The antibacterial activities of the oils against seven pathogenic strains, Pseudomonas aeruginosa, Bacillus cereus, Salmonella, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis and Micrococcus luteus, were tested. The highest and broadest activity was shown by M. piperita; however, Ocimum basilicum was inactive against all strains. Essential oils were also evaluated for antidiabetic and anti-acetylcholinesterase activities. The IC₅₀ values of A. herba-alba and O. basilicum against α-amylase were respectively 17.76 and 16.32 µg/mL suggesting a powerful anti-diabetic effect comparable to that of acarbose (IC₅₀?=?14.88 µg/mL). R. officinalis, M. piperita and A. absinthium exhibited an interesting acetylcholinesterase inhibition with IC₅₀ equal to 22, 24 and 58 µg/mL respectively.