RESUMO
Robusta and Arabica green beans were supplemented with carbon 14-glyphosate labelled on each carbon position alternatively prior to roasting, up to 220 °C for Robusta and 200 °C for Arabica (2, 5 and 10 min). The results of the study point a significant decomposition of glyphosate that happens during roasting, from at least 42 % to > 74 % depending on roasting conditions (time, temperature) and coffee variety. The data obtained with 14C-labelled glyphosate materials suggest that the carboxymethyl branch of the compound degrades more effectively than the phosphonomethyl moiety. The degradation of glyphosate does not lead to the formation of aminomethylphosphonic acid (AMPA). The results of the study indicate that carbon dioxide, methylamine and dimethylamine are major degradation products of glyphosate formed along coffee roasting, likely released with the roasting gas. Ultimately, the results of the study show that levels of glyphosate in green beans do not mirror those in coffee beverages.
Assuntos
Coffea , Coffea/química , Sementes/química , Temperatura Alta , Radioisótopos de Carbono , GlifosatoRESUMO
In this study, 6:2 and 8:2 polyfluoroalkyl phosphate diester (diPAP) were individually investigated in lysimeters under near-natural conditions. Leachate was sampled for 2 years, as was the soil after the experiment. In the leachate of the diPAP-spiked soils, perfluorocarboxylic acids (PFCAs) of different chain lengths were detected [23.2% (6:2 diPAP variant) and 20.8% (8:2 diPAP variant) of the initially applied molar amount]. After 2 years, the soils still contained 36-37% 6:2 diPAP and 41-45% 8:2 diPAP, respectively, in addition to smaller amounts of PFCAs (1.5 and 10.6%, respectively). Amounts of PFCAs found in the grass were low (<0.1% in both variants). The recovery rate of both 6:2 diPAP and 8:2 diPAP did not reach 100% (63.9 and 83.2%, respectively). The transformation of immobile diPAPs into persistent mobile PFCAs and their transport into the groundwater shows a pathway for human exposure to hazardous PFCAs through drinking water and irrigation of crops.
Assuntos
Fluorocarbonos , Poluentes Químicos da Água , Humanos , Fosfatos/metabolismo , Fluorocarbonos/análise , Organofosfatos/metabolismo , Solo , Produtos Agrícolas/metabolismoRESUMO
Fluorotelomer precursors in soil constitute a reservoir for perfluoroalkyl acids (PFAAs) in the environment. In the present study, precursor degradation and transfer rates of seven fluorotelomer precursors and F-53B (chlorinated polyfluoroalkyl ether sulfonates) were investigated in pot experiments with maize plants (Zea mays L.). The degradation of fluorotelomer precursors to perfluoroalkyl carboxylic acids (PFCAs) and their uptake spectra corresponded to those of fluorotelomer alcohol (FTOH) in terms of the number of perfluorinated carbon atoms. Short-chain PFCAs were translocated into the shoots (in descending order perfluoropentanoic, perfluorobutanoic, and perfluorohexanoic acid), whereas long-chain PFCAs mainly remained in the soil. In particular, fluorotelomer phosphate diesters (diPAPs) were retained in the soil and showed the highest degradation potential including evidence of α-oxidative processes. F-53B did not degrade to PFAAs and its constituents were mainly detected in the roots with minor uptake into the shoots. The results demonstrate the important role of precursors as an entry pathway for PFCAs into the food chain.
Assuntos
Fluorocarbonos , Ácidos Carboxílicos/metabolismo , Fluorocarbonos/análise , Fosfatos/metabolismo , Solo , Zea mays/metabolismoRESUMO
Per- and polyfluoroalkyl substances (PFAS) are environmentally ubiquitous, anthropogenic substances with adverse effects on organisms, which shows the need to study their environmental fate and leaching behavior. In the present soil columns study, the leaching behavior and fate of nontransformable and transformable (precursors) were investigated. Ten nontransformable PFAS in two different soils, two precursors and two field soils, which were already contaminated with a mixture of PFAS, and two uncontaminated controls, were set up for a time span of 2 years. At the end of the study, the molecular balance could not be closed for nontransformable PFAS. This effect was positively correlated to the fluorinated carbon chain length. The precursors, which were both polyfluoroalkyl phosphate diesters (diPAP), had different transformation products and transformation rates, with a higher rate for 6:2 diPAP than 8:2 diPAP. After 2 years, amounts of diPAP were still found in the soil with no significant vertical movement, showing high adsorption to soils. Transformation products were estimated to be simultaneously formed. They were predominantly found in the percolation water; the amounts left in soil were negligible. Up to half of the initial precursor amounts could not be balanced and were considered missing amounts. The results of contaminated field soil experiments showed the challenge to estimate PFAS leaching without knowing all occurring precursors and complex transformation dynamics. For this purpose, it was shown that a broad examination of contaminated soil with different analytical methods can help with qualitative estimations of leaching risks. For a better quantitative estimation, analytical determination of more PFAS and a quantification of the missing amounts are needed. Environ Toxicol Chem 2022;41:2065-2077. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
Assuntos
Fluorocarbonos , Poluentes do Solo , Poluentes Químicos da Água , Organofosfatos , Fosfatos , Solo/química , Poluentes Químicos da Água/análiseRESUMO
A feeding study was performed to examine the bioaccumulation of per- and polyfluoroalkyl substances (PFAS) in laying hens' tissues and plasma and feed-to-egg transfer rates and half-lives. A 25 day exposure was followed by a 42 day depuration period. A target analysis revealed substantial amounts of the precursors N-methyl and N-ethyl perfluorooctane sulfonamidoacetic acid (Me- and EtFOSAA), perfluorooctane sulfonamidoacetic acid (FOSAA), and perfluorooctane sulfonamide (FOSA). In tissues and eggs, the highest bioaccumulation was found for PFHxS, PFHpS, PFOS, and PFOA. Low levels of PFHxS (all samples), PFOS, and FOSAA (in yolk) were measurable even after the depuration period. The egg elimination half-lives of PFOS and aforementioned precursors were estimated to be 4.3 days, while the transfer rates of PFOS and all precursors taken together were 0.99. The transfer rate of PFOA was around 0.49. PFHxS and PFHpS showed apparent transfer rates of >100%, which is hypothesized to indicate the presence of precursors.
Assuntos
Ácidos Alcanossulfônicos/química , Ração Animal/análise , Galinhas/metabolismo , Ovos/análise , Poluentes Ambientais/química , Fluorocarbonos/química , Contaminação de Alimentos/análise , Ácidos Alcanossulfônicos/metabolismo , Animais , Poluentes Ambientais/metabolismo , Feminino , Fluorocarbonos/metabolismo , ToxicocinéticaRESUMO
The group of per- and polyfluoroalkyl substances (PFAS) comprises thousands of chemicals, which are used in various industrial applications and consumer products. In this study, a feeding experiment with laying hens and feed grown on a contamination site was conducted, and PFAS were analyzed in the feed and eggs to assess the transfer of PFAS into eggs. A targeted analysis of perfluoroalkyl acids (PFAAs) and different sulfonamides was performed. Additionally, the total oxidizable precursor (TOP) assay was modified by fully oxidizing small amounts of the samples instead of oxidizing their extracts in order to overcome potential losses during extraction. Targeted analysis showed the presence of known PFAAs and four sulfonamides in the feed and egg yolk samples. In the plant-based feed, short-chain PFAAs, methyl and ethyl perfluorooctane sulfonamidoacetic acid (Me- and EtFOSAA), and perfluorooctane sulfonic acid (PFOS) were the most abundant PFAS. In the eggs, PFOS, FOSAA, and its alkylated homologues showed the highest concentrations. The TOP assay revealed the presence of substantial amounts of precursors with different chain lengths from C4 to C8. The highest relative increase of PFOA after oxidation was observed in egg yolk from the end of the exposure period (828%). The results of this study demonstrate the transfer of PFAAs and their precursors into hens' eggs and emphasize the contribution of (known and unidentified) precursors to the overall PFAS burden in edible products. The modified TOP assay approach was shown to be a powerful tool to better assess the total burden of samples with PFAS.
Assuntos
Ácidos Alcanossulfônicos/análise , Ração Animal/análise , Galinhas/metabolismo , Ovos/análise , Poluentes Ambientais/análise , Fluorocarbonos/análise , Contaminação de Alimentos/análise , Ácidos Alcanossulfônicos/metabolismo , Animais , Poluentes Ambientais/metabolismo , Feminino , Fluorocarbonos/metabolismo , OxirreduçãoRESUMO
The findings of per- and polyfluoroalkyl substances (PFAS) in humans and the environment all over the world have raised concerns and public awareness for this group of man-made chemicals. In the last three decades, this led to different regulatory restrictions for specific PFAS as well as shifts in the production and usage of these substances. In this study, we analyzed the PFAS levels of 100 human blood plasma samples collected from 2009 to 2019 for the German Environmental Specimen Bank (ESB) to further elucidate the time course of exposure towards this substance group as shown by Schröter-Kermani et al., (2013) with samples from 1982 to 2010. A spectrum of 37 PFAS, including perfluorocarboxylic (PFCA) and -sulfonic acids (PFSA) as well as potential precursors and substitutes like ADONA, GenX or F-53B was analyzed by UHPLC coupled with high-resolution mass spectrometry. Validation was successful for 33 of the substances. The two legacy substances perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were detected in every sample of the 2009-2019 dataset and showed the highest concentrations with ranges of 0.27-14.0 ng/mL and 1.21-14.1 ng/mL, respectively. A significant portion of total PFOS analytes was present as branched isomers (mean: 34 ± 7%). High detection frequencies of 95% and 82% were also found for perfluorohexane sulfonic acid (PFHxS) and perfluorononanoic acid (PFNA), respectively, but in lower concentrations (PFHxS: Assuntos
Ácidos Alcanossulfônicos
, Poluentes Ambientais
, Fluorocarbonos
, Monitoramento Biológico
, Caprilatos
, Alemanha
, Humanos
, Plasma
, Ácidos Sulfônicos
RESUMO
Per- and polyfluoroalkyl substances (PFAS) in the environment mostly originate from emissions of previously unregulated PFAS. However, there are also many documented incidents of accidental releases. To track such releases, it is essential to distinguish between typical background contamination and legally relevant incidents. This requires a comprehensive overview of all PFAS present in the environment, which is currently only possible to a limited extent due to the large variety of individual compounds. In the present study, a multimethod for capturing 41 PFAS including perfluoroalkyl acid (PFAA) precursors is introduced. The applicability of the method was tested on terrestrial, freshwater and marine samples from the German Environmental Specimen Bank (ESB), thereby providing a rough overview of PFAS contamination in German environment. Special focus was put on soil samples from ESB sites across Germany in comparison to soil samples from a polluted site in south-west Germany. The method was successfully applied to environmental samples. In total, 31 PFAS were detected, among them PFAA precursors and fluorinated ethers. Substance patterns differed between sites and matrices. In ESB soil samples from 2014 (n = 11), the sum of all captured PFAS ranged between 0.75 and 19.5 µg kg-1 dry weight (dw), while concentrations between 416 µg kg-1 and 3530 µg kg-1 were detected in samples from the incident site (n = 10). In other matrices, total PFAS concentrations were magnitudes lower. Highest concentrations were observed for PFOS in bream livers from the Saale (226 µg kg-1). Given the heterogeneous patterns, it will require further broadly-based monitoring data to allow for a solid estimation of relevant background levels. The data provided here may support the differentiation between background levels and hotspot contaminations.
RESUMO
Chlorpropham is a widely used sprouting inhibitor applied on potatoes during their storage. Currently, severe concerns are raised regarding the potential formation of 3-chloroaniline from chlorpropham during heat treatment. The reactions degrading the molecule in the matrix are quite complex under harsh processing conditions, and a molecular investigation is thus challenging. This study aims to decipher the reaction pathways and to discover new metabolites in typical high-temperature food-processing steps. For this purpose, potatoes were treated with 14C-radiolabeled chlorpropham, stored for up to 6 months, and subjected to the traditional preparation steps of boiling, frying, and baking. A quantification method including an acidic hydrolysis was developed for analysis of free and bound analytes. All conducted processing steps led to a substantial mitigation of chlorpropham residues in the consumable products. Of the residues, 17 ± 6% remained in boiled tubers, while 27 ± 3 and 22 ± 3% remained in the fried and baked products, respectively. Chlorpropham was transferred into the surrounding media (boiling water, frying oil, and air, respectively). 3-Chloroaniline was only (raw tubers) or predominantly (processed tubers) present as a bound analyte and was shown to form during storage but not during processing. Additionally, nonextractable and nonquantified residues were detected in the baked and in the long-term-stored tubers after processing. Future studies will have to balance beneficial (mitigating) and potentially hazardous aspects of these results. By transferring the 14C-food-processing approach to a variety of substances, ingredients, and processes, it will be possible to further understand chemical reactions in food processing, finally leading to safer food.
Assuntos
Clorprofam/química , Herbicidas/química , Solanum tuberosum/química , Culinária , Temperatura Alta , Resíduos de Praguicidas/química , Tubérculos/químicaRESUMO
Analyzing the fate of substances in complex matrices, such as processed food, is a major challenge in modern analytical chemistry. However, current regulatory procedures for pesticides only include high temperature hydrolysis of the active substance in water (OECD 507) to simulate food processing. This study shows that heating radiolabeled [imidazolyl-2-14C]prochloraz in virgin rapeseed oil at temperatures up to 240 °C leads to an extensive degradation of the active substance. In total, 11 degradation products were identified. Several of these products were formed by reactions of the active substance with ingredients from the oil. 2-[(1-H-Imidazole-1-carbonyl)(propyl)amino]ethyl oleate (icpame-oleate), a reaction product of an oleic acid moiety and the prochloraz backbone, was identified for the first time. The quantification of prochloraz, icpame-oleate, imidazole, and 2,4,6-trichlorophenol demonstrated the dependency of the degradation process on temperature, heating duration, and type of oil. The obtained results in this study show the enormous impact of high temperature food processing on the fate of pesticides. The necessity to consider matrix related reactions in pesticide regulation is emphasized, and the suitability of the OECD 507 guideline is questioned. Concerning possible toxicological risks of novel degradation products, future studies will have to assess potential hazards or opportunities of food processing, ultimately yielding in safer food.
Assuntos
Imidazóis/química , Resíduos de Praguicidas/química , Óleo de Brassica napus/química , Culinária , Temperatura Alta , Estrutura MolecularRESUMO
In this paper, a novel sensor platform based on screen printed carbon electrode coated by graphene modified polyacrylamide gel (GR/PAAGC) was developed and implemented for sampling, detection and enumeration of coliform bacteria (coliforms) on food contact surfaces. The optimized formula of polyacrylamide (PAA) and agar-agar increased the adhesive properties of the gel, being crucial for the coliforms recovery, attached to food contact surfaces. The 6-Chloro-3-indoxyl-ß-D-galactopyranoside (6-CIGP) was used as a new electrochemical reporter for ß-D-galactosidase activity. The released 6,6'-Dichloro-Indigo (6-DI) was directly detected by GR/PAAGC sensor. The presence of Isopropyl-ß-D-thiogalactopyranoside (IPTG) and n-Octyl-ß-D-thiogalactopyranoside (OBDG) in the gel contributed to reduction of the detection time. The addition of graphene enhanced the voltammetric signal and increased the conductivity of PAA gel. The anodic and cathodic peaks of the released product were directly proportional to the concentration of coliforms. Bacterial cell concentrations ranging from 1.6log10CFU/mL to 6.6log10CFU/mL were detected. Well-shaped, sharp voltammetric curves were generated within 3â¯h. Redox peaks exhibited good sensitivity with detection limits (LOD)â¯<â¯0.6log10CFU/mL. After series of optimization experiments, coliforms ranging from 0.6log10CFU/cm2 to 6.610CFU/cm2 on stainless steel surfaces have been detected within 30â¯min with a LOD of 0.1log10CFU/cm2. The developed rapid, sensitive, reproducible and specific sensor successfully applied for single detection as well as for real-time monitoring of growth of coliform bacteria on stainless steel surfaces during food processing.
Assuntos
Contagem de Colônia Microbiana/métodos , Enterobacteriaceae/isolamento & purificação , Microbiologia de Alimentos/métodos , Eletroquímica , Enterobacteriaceae/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/isolamento & purificação , Microbiologia de Alimentos/instrumentação , Grafite/farmacologia , Concentração de Íons de Hidrogênio , Propriedades de Superfície , beta-Galactosidase/metabolismoRESUMO
Per- and polyfluoroalkyl substances (PFAS) represent a versatile group of ubiquitously occurring chemicals of increasing regulatory concern. The past years lead to an ever expanding portfolio of detected anthropogenic PFAS in numerous products encountered in daily life. Yet no clear picture of the full range of individual substance that comprise PFAS is available and this challenges analytical and engineering sciences. Authorities struggle to cope with uncertainties in managing risk of harm posed by PFAS. This is a result of an incomplete understanding of the range of compounds that they comprise in differing products. There are analytical uncertainties identifying PFAS and estimating the concentrations of the total PFAS load individual molecules remain unknown. There are four major trends from the chemical perspective that will shape PFAS research for the next decade. Mobility: A wide and dynamic distribution of short chain PFAS due to their high polarity, persistency and volatility.Substitution of regulated substances: The ban or restrictions of individual molecules will lead to a replacement with substitutes of similar concern.Increase in structural diversity of existing PFAS molecules: Introduction of e.g., hydrogens and chlorine atoms instead of fluorine, as well as branching and cross-linking lead to a high versatility of unknown target molecules.Unknown "Dark Matter": The amount, identity, formation pathways, and transformation dynamics of polymers and PFAS precursors are largely unknown. These directions require optimized analytical setups, especially multi-methods, and semi-specific tools to determine PFAS-sum parameters in any relevant matrix.
RESUMO
The use of polymer coated surface acoustic wave (SAW) sensor arrays is a very promising technique for highly sensitive and selective detection of volatile organic compounds (VOCs). We present new developments to achieve a low cost sensor setup with a sampling method enabling the highly reproducible detection of volatiles even in the ppb range. Since the VOCs of coffee are well known by gas chromatography (GC) research studies, the new sensor array was tested for an easy assessable objective: coffee ageing during storage. As reference method these changes were traced with a standard GC/FID set-up, accompanied by sensory panellists. The evaluation of GC data showed a non-linear characteristic for single compound concentrations as well as for total peak area values, disabling prediction of the coffee age. In contrast, the new SAW sensor array demonstrates a linear dependency, i.e. being capable to show a dependency between volatile concentration and storage time.
Assuntos
Cromatografia Gasosa/métodos , Café/química , Técnicas Analíticas Microfluídicas/métodos , Microextração em Fase Sólida/métodos , Benzenossulfonatos , Compostos Orgânicos VoláteisRESUMO
This study investigated the impact of assessors' varying olfactory acuity on the perceived intensity of androstenone and skatole odour and flavour in boar loins. To discriminate sensitive (SENS) and highly sensitive (SENSHIGH) panellists, two levels of androstenone were used on smell strips. Sensitivity was defined as the correct identification of the androstenone strip in three replicate triangle tests. Judges then assessed loins from boars, castrated pigs and gilts. SENSHIGH assessors scored low-fat boar loins with 1.5 to 2.0µg of androstenone per gram of melted back fat which is significantly different from castrate and gilt loins for androstenone odour and flavour whereas SENS assessors were less discriminating. Panellists' olfactory acuity should thus be considered for selection and training. The presented paper strip system is suggested for objective screening and training purposes and to be used as quantitative references in descriptive analysis.
Assuntos
Androstenos/análise , Carne/análise , Odorantes/análise , Percepção , Escatol/análise , Olfato , Paladar , Tecido Adiposo/química , Animais , Castração , Dieta , Gorduras na Dieta/análise , Análise de Alimentos/métodos , Humanos , Masculino , Percepção Olfatória , Limiar Sensorial , SuínosRESUMO
This study aimed to assess the influence of two label conditions on the acceptance of boar meat. A central location test was conducted with 145 consumers each assessing 4 pieces of pork loin. Samples varied with respect to two factors: actual meat type (boar vs. standard pork) and label information (young boar meat vs. pork). Androstenone and skatole levels in the tested boar meat ranged from 0.51 to 2.72 µg/g and 0.01 to 0.23 µg/g melted fat, respectively. Consumers' sensitivity to and appreciation of androstenone and skatole odour was determined through a smell experiment. The acceptance of taste, tenderness, juiciness, and overall liking was neither influenced by the label information nor by the meat type. Twenty-seven % of all participants were classified as insensitive to androstenone odour, whereas 52% perceived it as positive and 21% as negative. Consumers who disliked the androstenone odour indicated a higher disliking of boar meat.
Assuntos
Androstenos/análise , Carne/análise , Odorantes/análise , Percepção Gustatória/fisiologia , Paladar/fisiologia , Adulto , Animais , Comportamento do Consumidor , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Escatol/análise , Inquéritos e Questionários , Suínos , Adulto JovemRESUMO
The prevention of unpleasant boar taint is the main reason for castration of male piglets. For animal welfare reasons, castration is announced to be banned in the European Community. This study aimed to investigate whether androstenone, skatole and indole in backfat of boars may be reduced by different scalding technologies. To discriminate ante and post mortem effects, carcasses were sampled before and after scalding in two abattoirs using either horizontal (TANK) or vertical (TUNNEL) scalding. Backfat samples were analysed using gas chromatography (androstenone) and liquid chromatography (skatole, indole). Neither TANK nor TUNNEL scalding did significantly reduce malodorous compounds. Skatole and androstenone in backfat obtained after scalding averaged 112 ± 123 ng/g and 1196 ± 885 ng/g melted fat, respectively; significant differences between abattoirs were observed for skatole. Increased skatole levels were tentatively assigned to longer transport duration. Concluding from recent consumer research and subsequent application of suggested sensory rejection thresholds for androstenone (2000 ng/g) and skatole (150 ng/g), nearly 30% of the carcasses may be unacceptably tainted.
Assuntos
Tecido Adiposo/química , Androstenos/análise , Gorduras na Dieta/análise , Temperatura Alta , Carne/análise , Odorantes/análise , Escatol/análise , Matadouros , Animais , Indóis/análise , Masculino , Mudanças Depois da Morte , Suínos , ÁguaRESUMO
The steroidal pig pheromones androstenone (5α-androst-16-en-3-one), 3α-androstenol (5α-androst-16-en-3α-ol), and 3ß-androstenol (5α-androst-16-en-3ß-ol) as well as the heterocyclic aromatic amines skatole and indole, originating from microbial degradation of tryptophan in the intestine of pigs, are frequently recognized as the major compounds responsible for boar taint. A new procedure, applying stable isotope dilution analysis (SIDA) and headspace solid-phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS) for the simultaneous quantitation of these boar taint compounds in pig fat was developed and validated. The deuterated compounds androstenone-d(3), 3ß-androstenol-d(3), skatole-d(3), and indole-d(6) were synthesized and successfully employed as internal standards for SIDA. The new procedure is characterized by a fast, simple, and economic sample preparation: methanolic extraction of the melted fat followed by a freezing and an evaporation step allows for extraction and enrichment of all five analytes. Additional time-consuming cleanup steps were not necessary, as HS-SPME sampling overcomes fat-associated injector and column contamination. The method has been validated by determining intra- and interday precision and accuracy as well as the limit of detection (LOD) and limit of quantitation (LOQ). Additionally, a cross-validation for androstenone, skatole, and indole was carried out comparing the results of 25 back fat samples obtained simultaneously by the new SIDA-HS-SPME-GC/MS procedure with those obtained in separate GC/MS and high-performance liquid chromatography fluorescence detection (HPLC-FD) measurements. The cross-validation revealed comparable results and confirms the feasibility of the new SIDA-HS-SPME-GC/MS procedure.
Assuntos
Tecido Adiposo/química , Androstenos/análise , Androstenóis/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Indóis/análise , Escatol/análise , Microextração em Fase Sólida/métodos , Androstenos/isolamento & purificação , Androstenóis/isolamento & purificação , Animais , Calibragem , Deutério/química , Cromatografia Gasosa-Espectrometria de Massas/normas , Indóis/isolamento & purificação , Marcação por Isótopo , Escatol/isolamento & purificação , Microextração em Fase Sólida/normas , SuínosRESUMO
To identify the component(s) causing the foxy odor, characteristic for some Fritillaria imperialis cultivars, the headspace of flower bulbs was analyzed using gas chromatography-olfactometry (GC-O) and GC-mass spectrometry (GC-MS). Six Fritillaria species and cultivars were selected as follows: F. imperialis cv. Premier (very strong foxy odor), F. imperialis cv. Lutea (strong foxy odor), F. imperialis ssp. Inodora (no odor), Fritillaria eduardii (weak mousy odor), Fritillaria raddeana (no odor), and an F1 of F. imperialis Lutea x Inodora (weak foxy odor). Volatiles from these flower bulbs were accumulated on Tenax and injected into the GC by thermodesorption. The majority of the volatiles consisted of low molecular weight aliphatic compounds. GC-O revealed that the foxy odor was caused by a single component, identified as 3-methyl-2-butene-1-thiol on the basis of smell in GC-O analyses (two GC columns), mass spectra, and retention times. Chemical identification was substantiated by GC-O and GC-MS of an authentic standard of 3-methyl-2-butene-1-thiol, prepared by organic synthesis.
Assuntos
Fritillaria/química , Odorantes/análise , Butanos/análise , Cromatografia Gasosa , Cromatografia Gasosa-Espectrometria de Massas , Raízes de Plantas/química , Olfato , Compostos de Sulfidrila/análise , VolatilizaçãoRESUMO
Previous investigations of coffee flavor have been confined to the analysis of the aroma substances. These investigations showed that about 30 volatile compounds were substantially responsible for the coffee flavor. The aim of this study was to investigate the influence of different milk additives and one coffee whitener on the release of flavor impact compounds from coffee beverages. For the investigation of these effects an external static headspace technique was developed. With this technique the most potent odorants of the coffee beverage were determined. Analyses were performed by gas chromatography/olfactometry, flame ionization detection, and mass spectrometric detection. In addition, sensory studies of the odor profiles were performed. Milk and vegetable products as additives for coffee beverages affected the release of aroma substances in the brew through their lipid, protein, and carbohydrate components. All beverages with an additive showed reduced, but typical, odor profiles for each additive.