Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 975
Filtrar
1.
J Agric Food Chem ; 68(8): 2562-2569, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32003990

RESUMO

This study was aimed to evaluate the level of furan and acrylamide contamination in cocoa and noncocoa raw materials, in masses from processing stages, and in chocolates originating from three factories. Acrylamide was determined by the gas chromatography-mass spectrometry (GC-MS) method using the QuEChERS procedure with dispersive solid-phase extraction clean-up and isotopic standard (2,3,3-d3-acrylamide). Furan was analyzed by the headspace solid-phase microextraction/GC-MS technique with the d4-furan marker. Both analytical methods were validated in terms of accuracy, precision, and linearity as well as the limit of detection (LOD) and limit of quantification (LOQ). Among all raw materials, the most abundant in acrylamide were cocoa masses and powders (83.0-127.5 ng g-1). Roasting of cocoa beans increased the content of acrylamide 2-3-fold. The obtained results indicate that acrylamide might be formed during wet conching. Only in cocoa powders and lecithin, it was possible to quantify furan (3.7-10.2 and 16.3 ng g-1, respectively). Roasting of cocoa beans increased the content of furan from

Assuntos
Acrilamida/análise , Cacau/química , Chocolate/análise , Furanos/análise , Acrilamida/isolamento & purificação , Contaminação de Alimentos/análise , Manipulação de Alimentos , Furanos/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Sementes/química , Microextração em Fase Sólida
2.
Molecules ; 25(2)2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31936132

RESUMO

The volatiles of cape gooseberry fruit (Physalis peruviana L.) were isolated by solvent-assisted flavor evaporation (SAFE), odor active compounds identified by gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). Quantitation of compounds was performed by headspace-solid phase microextraction (HS-SPME) for all but one. Aroma extract dilution analysis (AEDA) revealed 18 odor active regions, with the highest flavor dilution values (FD = 512) noted for ethyl butanoate and 4-hydroxy-2,5-dimethylfuran-3-one (furaneol). Odor activity values were determined for all 18 compounds and the highest was noted for ethyl butanoate (OAV = 504), followed by linalool, (E)-non-2-enal, (2E,6Z)-nona-2,6-dienal, hexanal, ethyl octanoate, ethyl hexanoate, butane-2,3-dione, and 2-methylpropanal. The main groups of odor active compounds in Physalis peruviana L. were esters and aldehydes. A recombinant experiment confirmed the identification and quantitative results.


Assuntos
Aromatizantes/química , Frutas/química , Odorantes/análise , Physalis/química , Compostos Orgânicos Voláteis/química , Monoterpenos Acíclicos/análise , Monoterpenos Acíclicos/química , Aldeídos/química , Ésteres/análise , Aromatizantes/isolamento & purificação , Furanos/análise , Furanos/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Olfatometria/métodos , Olfato/fisiologia , Microextração em Fase Sólida/métodos , Paladar/fisiologia , Compostos Orgânicos Voláteis/isolamento & purificação
3.
Food Chem ; 313: 125930, 2020 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31923863

RESUMO

A method based on gas chromatography coupled with triple quadrupole mass spectrometry (GC-MS/MS) combined with QuEChERS extraction was developed to detect furfurals, including furfural, 2-acetylfuran, 5-methyl-2-furfural, and 5-hydroxymethyl-2-furfural, in milk-based dairy products. Under the optimized conditions, good linearity was obtained with correlation coefficients (R2) above 0.999, and the recovery values from the spiked samples were 79.0%-115.0% with relative standard deviations (RSDs) less than 13.1%. The limits of detection (LODS) were in the range of 0.002-0.02 mg/kg. To investigate the effects of the production process on milk-based dairy products, 55 real samples were analysed. The higher contents of furfurals were observed when higher temperatures were used during heat treatment and fermentation. In addition, the Toxtree and T.E.S.T. software programs were used to predict the risks associated with these four furfurals. Ultimately, safe dairy intake levels were determined.


Assuntos
Laticínios/análise , Furaldeído/análise , Leite/química , Animais , Furaldeído/análogos & derivados , Furanos/análise , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Temperatura
4.
Artigo em Inglês | MEDLINE | ID: mdl-31622171

RESUMO

Carbonyl compounds and furan derivatives may form adducts with DNA and cause oxidative stress to human cells, which establishes the carcinogenic potential of these compounds. The occurrence of these compounds may vary according to the processing characteristics of the beer. The objective of this study was, for the first time, to investigate the free forms of target carbonyl compounds [acetaldehyde, acrolein, ethyl carbamate (EC) and formaldehyde] and furan derivatives [furfural and furfuryl alcohol (FA)] during the brewing stages of ale and lager craft beers. Samples were evaluated using headspace-solid phase microextraction and gas chromatography with mass spectrometric detection in selected ion monitoring mode (HS-SPME-GC/MS-SIM). Acetaldehyde, acrolein, formaldehyde and furfuryl alcohol were found in all brewing stages of both beer types, while EC and furfural concentrations were below the LOD and LOQ of the method (0.1 and 0.01 µg L-1, respectively). Boiling and fermentation of ale brewing seem to be important steps for the formation of acrolein and acetaldehyde, respectively, while boiling resulted in an increase of FA in both types of beer. Conversely, pasteurisation and maturation reduced the levels of these compounds in both types of beer. An increase in concentration of acrolein has not been verified in lager brew probably due to the difference in boiling time between these two types of beer (60 and 90 min for ale and lager, respectively).


Assuntos
Cerveja/análise , Análise de Alimentos , Contaminação de Alimentos/análise , Acetaldeído/efeitos adversos , Acetaldeído/análise , Acroleína/efeitos adversos , Acroleína/análise , Cerveja/efeitos adversos , Fermentação , Formaldeído/efeitos adversos , Formaldeído/análise , Furanos/efeitos adversos , Furanos/análise , Humanos , Uretana/efeitos adversos , Uretana/análise
5.
Biomed Chromatogr ; 34(1): e4714, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31633806

RESUMO

Eucommia ulmoides Oliv. (E. ulmoides) is a valuable and nourishing medicinal herb in China that has been used in the treatment of hypertension. Given the fact that most traditional Chinese medicine is mainly used to treat disease, investigating the pharmacokinetics of traditional Chinese medicines in the pathological state is more useful than that in the normal state. However, the differences in the absorption kinetics of active ingredients of E. ulmoides extract between pathological and physiological conditions have not been reported. Therefore, in this study, the rat intestinal in situ circulatory perfusion model was used to investigate the differences in absorption kinetics of seven active ingredients of E. ulmoides extract in normal and spontaneously hypertensive rats, namely, genipinic acid, protocatechuic acid, neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, (+)-pinoresinol di-O-ß-D-glucopyranoside and (+)-pinoresinol 4'-O-ß-D-glucopyranoside. Our results indicate that the pathological state of spontaneous hypertension may change the absorption of active components of E. ulmoides extracts, and these findings may provide a reference for improving the rational use of E. ulmoides in the clinic.


Assuntos
Eucommiaceae , Absorção Intestinal , Extratos Vegetais , Animais , Anti-Hipertensivos/análise , Anti-Hipertensivos/farmacocinética , Líquidos Corporais/química , Ácido Clorogênico/análogos & derivados , Ácido Clorogênico/análise , Ácido Clorogênico/farmacocinética , Furanos/análise , Furanos/farmacocinética , Hidroxibenzoatos/análise , Hidroxibenzoatos/farmacocinética , Lignanas/análise , Lignanas/farmacocinética , Extratos Vegetais/análise , Extratos Vegetais/farmacocinética , Ratos , Ratos Endogâmicos SHR , Ratos Wistar
6.
J Chromatogr A ; 1609: 460497, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31500883

RESUMO

This study introduces micrometric carbon strands as a suitable fiber for headspace solid phase microextraction. Compared to previous supports, carbon fibers have mechanical flexibility, wide thermal expansion, and a large surface area, which is an important factor in headspace solid phase microextraction. The electrophoretic technique was applied to modify the surface of stainless steel and carbon fibers with polypyrrole. Modified carbon fibers were used for extraction of 2-pentylfuran (2-PF) as a model analyte from patients' breath and coffee samples. 2-PF belongs to the furan family, which was suggested as a biomarker for Aspergillus fumigatus and was classified as a possible carcinogen. 2-PF can be found in many heat-processed foods and drinks. The separation and detection of the analyte was performed by gas chromatography coupled to mass spectrometry. The effective factors in the extraction performance of the analyte by carbon fiber supports were investigated and optimized. Under optimized extraction conditions (temperature, 20 °C; time, 15 min; desorption temperature, 200 °C; desorption time, 2 min; salt concentration, 10% w/v; and stirring rate, 700 rpm), the limit of detection was calculated as 0.05 ng mL-1, whereas repeatability and fiber-to-fiber reproducibility (RSD %) was found to be in the range of 3.2-4.1%. The experimental results showed that the proposed fiber had greater extraction performance for 2-pentylfuran.


Assuntos
Testes Respiratórios/métodos , Fibra de Carbono/química , Furanos/análise , Polímeros/química , Pirróis/química , Microextração em Fase Sólida/métodos , Adolescente , Adsorção , Adulto , Biomarcadores/análise , Feminino , Humanos , Limite de Detecção , Masculino , Nitrogênio/química , Reprodutibilidade dos Testes , Temperatura , Adulto Jovem
7.
Food Chem ; 303: 125406, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472386

RESUMO

This study reports the heat-induced formation of furan by decarboxylation of 2-furoic acid, and 2-methylfuran by dehydration of furfuryl alcohol under dry conditions. Model systems were incubated at temperatures up to 190 °C, followed by quantitative determination of furan and 2-methylfuran performed by isotope dilution headspace gas chromatography-mass spectrometry. Results show that 2-furoic acid decarboxylation and furfuryl alcohol dehydration are activated as from about 140-160 °C. Furfuryl alcohol and 2-furoic acids were measured in a selection of roasted coffee products by isotope dilution liquid chromatography-high resolution mass spectrometry, and the data evidenced a strong correlation between the two compounds, suggesting an intimate mechanistic relationship between them. The possible oxidation of furfuryl alcohol to furfural and 2-furoic acid in heated food is raised with particular emphasis on coffee roasting. These findings are relevant for better understanding the formation of furan and alkylfurans in food, and ultimately opening avenues for mitigation.


Assuntos
Furanos/análise , Furanos/química , Coffea/química , Culinária , Contaminação de Alimentos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Temperatura Alta , Sementes/química
8.
Artigo em Inglês | MEDLINE | ID: mdl-31841980

RESUMO

Shikonin, shikonofuran and their derivatives are the main bioactive components of Zicao, a traditional Chinese medicine prepared with the dried roots of Lithospermum erythrorhizon, Arnebia euchroma or Arnebia guttata. To establish an efficient and sensitive method for studying material basis of Zicao, different scan modes of ultra-high performance liquid chromatography quadrupole time of flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) and UHPLC triple quadrupole linear ion trap mass spectrometry (QTRAP-MS/MS) were incorporated to make full use of the sensitivity of multiple reaction monitoring (MRM) and overcome its disadvantages. A total of 73 shikonins and shikonofurans compounds were detected in Zicao utilizing various scanning modes. Thereafter the characteristic chemical profile for shikonins and shikonofurans was established based on UHPLC-QTRAP-MS/MS, which was subsequently used to study the spectrum-effect relationship by correlating the relative quantity of compounds and the anti-tumor activity. As a result, 27 compounds were screened as the main active components inhibiting HeLa cells by othogonal partial least square (OPLS). Among them, shikonin, acetylshikonin have been reported to inhibit HeLa cells previously, and ß, ß-dimethylacrylshikonin has been reported to be active component by other method. Those results showed that chemical characteristic profile combined with chemometric methods was efficient and reliable for discovery of material basis in TCM, especially trace active compounds.


Assuntos
Antineoplásicos , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas , Naftoquinonas , Espectrometria de Massas em Tandem/métodos , Antineoplásicos/análise , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Medicamentos de Ervas Chinesas/análise , Medicamentos de Ervas Chinesas/química , Furanos/análise , Furanos/farmacologia , Células HeLa , Humanos , Análise dos Mínimos Quadrados , Naftoquinonas/análise , Naftoquinonas/farmacologia
9.
Artigo em Inglês | MEDLINE | ID: mdl-31596176

RESUMO

Compounds with toxic potential may occur in beer, such as carbonyl compounds (acetaldehyde, acrolein, ethyl carbamate [EC] and formaldehyde) and furan derivatives [furfural and furfuryl alcohol (FA)]. The objective of this study was, for the first time, to validate a method based on headspace-solid phase microextraction using a PDMS-overcoated fibre and gas chromatography with mass spectrometric detection in selected ion monitoring mode (HS-SPME-GC/MS-SIM) to investigate target carbonyl compounds and furan derivatives in beers. Analytical curves showed proper linearity with r2 ranging from 0.9731 to 0.9960 for acetaldehyde and EC, respectively. The lowest LOD was found for acetaldehyde (0.03 µg L-1), while the lowest LOQ value (1.0 µg L-1) was found for acetaldehyde and EC, formaldehyde and furfural. Recovery (90% to 105%), intermediate precision and repeatability (lower than 13%), limits of detection and quantification (values below 2.5 µg L-1) showed that the method is suitable to simultaneously quantify these compounds. EC was detected in only two samples (1 lager and 1 ale). Furfural was found in 37% and 82% of ale and lager beers, respectively. Acetaldehyde, acrolein, formaldehyde and FA were detected in all samples. However, acrolein was the only compound found in the commercial samples at a concentration capable of causing health risk. Besides furfural and FA, four other furan-containing compounds (5-methyl-2-furan methanethiol, acetylfuran, 5-methylfurfural and γ-nonalactone) were also found in beers, however, at levels low enough not to impose potential health risk.


Assuntos
Cerveja/análise , Contaminação de Alimentos/análise , Microextração em Fase Sólida , Acetaldeído/análise , Acroleína/análise , Formaldeído/análise , Furanos/análise , Cromatografia Gasosa-Espectrometria de Massas , Estrutura Molecular , Medição de Risco , Uretana/análise
10.
Food Funct ; 10(10): 6882-6891, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31584595

RESUMO

Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) are isoprostanoids that result from the peroxidation of α-linolenic acid and are biomarkers of oxidative stress in plants and humans. These compounds exhibit several interesting biological activities (e.g. neuroprotection and anti-inflammatory activities). The aim of this research was to add value to coffee pulp (CP), cocoa husk (CH) and cocoa pod husk (CPH) by identifying and quantifying PhytoPs and PhytoFs by liquid chromatography-tandem mass spectrometry. The contents of PhytoPs and PhytoFs in CP, CH, and CPH were, respectively, 654.6, 474.3 and 179.9, and 543.2, 278.0 and 393.8 ng per g dry weight (dw). The main PhytoP found in CP (171.37 ng per g dw) and CPH (37.12 ng per g dw) was 9-epi-9-F1t-PhytoP, while ent-9-L1t-PhytoP was the most abundant in CH (109.78 ng per g dw). The main PhytoF found in all sources was ent-16(RS)-13-epi-ST-Δ14-9-PhytoF, at 196.56, 126.22, and 207.57 ng per g dw in CP, CH, and CPH, respectively. We provide the first complete profile of PhytoPs and PhytoFs for these agro-residues, which could be used in the functional food industry for enriching food or as nutritional supplements.


Assuntos
Cacau/química , Café/química , Furanos/análise , Furanos/isolamento & purificação , Ácidos Prostanoicos/análise , Ácidos Prostanoicos/isolamento & purificação , Biomarcadores , Cromatografia Líquida de Alta Pressão , Ácidos Graxos/isolamento & purificação , Estresse Oxidativo , Extratos Vegetais/química , Espectrometria de Massas em Tandem
11.
Artigo em Inglês | MEDLINE | ID: mdl-31584863

RESUMO

In the period from 2007 to 2017 furan levels of foods were analysed by the Austrian Agency for Health and Food Safety. Based on these analytical data and the Austrian consumption data the dietary exposure of children and adults to furan was estimated by using a deterministic approach. For the adult population the mean and 95th percentile dietary exposures to furan were estimated at 0.31 µg/kg bodyweight per day and at 0.72 µg/kg bodyweight per day, respectively. The mean dietary exposure of children was estimated at 0.18 µg/kg bodyweight per day and is thus only about half as high as for Austrian adults. At the 95th percentile the dietary exposure of children was estimated at 0.49 µg/kg bodyweight per day. The main contributor to the total dietary exposure for adults is coffee followed by convenience products and for children the main contributors are grain products as well as convenience products, bread and snacks. Based on the BMDL10 of 0.064 mg/kg bodyweight per day for the development of cholangiofibrosis, the MOE-calculation revealed that the current levels of dietary exposure to furan are of concern for Austrian adult high consumers. The MOE-calculation, based on the BMDL10 of 1.31 mg/kg bodyweight per day for the development of hepatocellular adenomas, indicated a health concern for Austrian children and adults.


Assuntos
Exposição Dietética/análise , Contaminação de Alimentos/análise , Furanos/análise , Adulto , Áustria , Criança , Café/química , Grão Comestível/química , Humanos
12.
Environ Pollut ; 255(Pt 1): 113159, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31541817

RESUMO

Elucidation of the relationship between the levels of 35 individual dioxins and polychlorinated biphenyl congeners in environmental samples (pine needles, leaves, grass and soil), and their bioaccumulation in the muscles of two game animal families (Cervidae and Suidae) was the aim of the research. Comparative studies were performed in four industrially degraded regions with various types of heavy industry and in an agricultural region with a tourism industry. The content of pollutants was determined by the isotopic dilution method using high resolution gas chromatography coupled with high resolution mass spectrometry. The polychlorinated dibenzodioxins/furan and PCB profiles in plants, soil and animal tissues varied by region and were related to the indigenous industry. The presence of characteristic congeners of particular industrial sectors was found. The animal tissue congeners were a reflection of the types and levels found in soil and plants. Independently of the region, deer tissue had almost twice the concentration of PCDD/F/DL-PCBs compared to boars, but the converse was true for NDL-PCBs. Spearman's statistical test showed strong correlations between pine needle, leaf, grass and soil dioxin and dioxin-like PCB levels and concentrations of these in the tissues of both species. Coefficients of bioaccumulation in deer muscles (BAF) calculated for all regions varied considerably and they were significantly higher for wild boars. BAF decreased with increasing number of chlorine atoms in the dioxin and furan molecule. The highest congener values were for 2,3,7,8-tetrachlorodibenzodioxin, 1,2,3,7,8-pentachlorodibenzodioxin, 2,3,7,8-tetrachlorodibenzofuran and 2,3,4,7,8-pentachlorodibenzofuran in both kinds of muscle regardless of the region. The levels of pollutants, types of pollutants, and their relative abundance in tissues of deer and boar reflected their surrounding environment and local pollutant emitters.


Assuntos
Bioacumulação/fisiologia , Dibenzofuranos Policlorados/análise , Dibenzofuranos Policlorados/farmacocinética , Dioxinas/análise , Dioxinas/farmacocinética , Poluição Ambiental/análise , Bifenilos Policlorados/análise , Bifenilos Policlorados/farmacocinética , Animais , Cervos , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Furanos/análise , Cromatografia Gasosa-Espectrometria de Massas , Indústrias , Músculos/química , Dibenzodioxinas Policloradas/análise , Solo/química , Sus scrofa , Suínos
13.
Forensic Sci Int ; 304: 109915, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31416646

RESUMO

Fatal intoxications due to accidental or voluntary intake of synthetic opioids represent an actual emerging issue. We report a case where we have analyzed furanyl fentanyl and its metabolite 4-anilino-N-phenetyl-piperidine (4-ANPP) in blood, urine, gastric content, bile and cerebrospinal fluid. In this case, a 53-year-old man was found dead at home with a needle still inserted in a vein; a plastic bag containing a white powder (later identified as a furanyl fentanyl-based product) was discovered in the room. Biological samples were collected during autopsy and extracted/purified onto a SPE cartridge before instrumental analysis. Qualitative and quantitative analyses were performed by LC-MS/MS on peripheral and cardiac blood, urine, cerebrospinal fluid (CSF), bile and gastric content. Furanyl fentanyl was identified and quantified in all the biological fluids collected. Interestingly, gastric content revealed an unexpected high amount of furanyl fentanyl; yet, cardiac blood and femoral blood provided significantly different concentrations (11.8 and 2.7 ng/g respectively). The concentration of furanyl fentanyl in CSF was similar to that measured in femoral blood (2.6 ng/mL), thus confirming that CSF could be a good alternative biological fluid whenever a postmortem redistribution is suspected. Concentrations of 93.5, 50.4, 171.7, 41.9, 10.2 ng/mL(g) were measured for 4-ANPP in cardiac blood, femoral blood, urine, bile and cerebrospinal fluid, respectively. The outcomes from the presented case report suggest that the two substances have been not only injected intravenously, but probably also ingested by the man. Fentanyl derivative and its precursor seemed to undergo an extensive postmortem redistribution.


Assuntos
Analgésicos Opioides/análise , Analgésicos Opioides/farmacocinética , Fentanila/análogos & derivados , Furanos/análise , Furanos/farmacocinética , Mudanças Depois da Morte , Bile/química , Cromatografia Líquida , Fentanila/análise , Fentanila/farmacocinética , Toxicologia Forense/métodos , Conteúdo Gastrointestinal/química , Humanos , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Transtornos Relacionados ao Uso de Opioides/complicações , Medicamentos Sintéticos/análise , Medicamentos Sintéticos/farmacocinética
14.
Analyst ; 144(17): 5254-5260, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31364615

RESUMO

In this paper we report a novel probe based on a luminescent 23-membered [1 + 1] Schiff-base macrocyclic mononuclear Sm(iii) complex Sm-2e, originating from the dialdehyde H2Qe and 1,2-bis(2-aminoethoxy)ethane precursors, which is synthesized by the Sm(iii) ion template method. X-ray structural analyses confirm that each ten-coordinate Sm(iii) center with the coordination geometry of a distorted bicapped square antiprism is fully encapsulated by a flexible macrocyclic ligand H2L2e to form a "lasso-type" architecture, and this architecture could enable efficient energy transfer in various solvents confirmed by long lifetimes (33.5-65.2 µs) and high quantum yields (0.23-0.76%) of the Sm(iii) ion. Simultaneously, complex Sm-2e could serve as a probe for sensing organic solvents. Particularly, this complex probe Sm-2e exhibits a highly selective, rapid and sensitive response to tetrahydrofuran (THF), which is easily distinguished by a large absorption shift, even visible to the naked eye, and complete fluorescence quenching. Moreover, the limit of detection for THF is about 0.20% determined by titration experiments, and good selectivity for THF could still be realized in mixture solvents. Consequently, this colorimetric and "turn off" fluorescent probe Sm-2e could be a valuable candidate as a sensor material for sensing THF which has been rarely reported.


Assuntos
Complexos de Coordenação/química , Corantes Fluorescentes/química , Furanos/análise , Colorimetria/métodos , Complexos de Coordenação/síntese química , Fluorescência , Corantes Fluorescentes/síntese química , Limite de Detecção , Samário/química , Bases de Schiff/síntese química , Bases de Schiff/química , Espectrometria de Fluorescência/métodos
15.
Food Chem ; 298: 125096, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31272051

RESUMO

The aim of this paper is to test different models for predicting furan content in a dough system, based on partial least squares regression using colour images. Starch dough systems were fried at five temperatures between 150 and 190 °C and for 5, 7, 9, 11 and 13 min. The furan content was quantified using gas chromatography/mass spectrometry, while the corresponding images were simultaneously obtained and processed in order to extract 2914 features. Good furan content predictions were obtained using computer vision image chromatic features using correlation coefficient of prediction (Rp = 0.86). However, the best prediction correlation was obtained using the image textural features (Rp = 0.93), when the number of features was reduced to 10 by algorithms applications. These results suggest that furan content in fried dough systems can be predicted using features of computer vision images.


Assuntos
Pão , Análise de Alimentos/métodos , Indústria de Processamento de Alimentos/métodos , Furanos/análise , Processamento de Imagem Assistida por Computador/métodos , Algoritmos , Cor , Culinária , Qualidade dos Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Análise dos Mínimos Quadrados , Amido , Triticum
16.
Food Chem ; 297: 124959, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253273

RESUMO

Volatile sulfur-containing compounds (VSCs) often exist at extremely low concentrations, making them difficult to be determined. The VSCs in Laobaigan (LBG) Baijiu were analyzed by headspace solid-phase microextraction (HS-SPME) coupled with GC × GC-SCD, by which 12 VSCs were identified. Among the 65 odor-active compounds that were determined by GC-O with the aid of aroma extract dilution analysis (AEDA), benzenemethanethiol and 2-methyl-3-furanthiol were found to possess the highest FD values of 6561. The limits of detection (LODs) of the identified VSCs determined by GC × GC-SCD were found to be extremely low at 0.05-1.53 ng/L, with their analytical recoveries from 85% to 116%. The VSCs in the LBG samples were determined in a range of concentrations from 0.77 ±â€¯0.02 µg/L to 60.04 ±â€¯2.32 µg/L. Benzenemethanethiol, dimethyl trisulfide, 2-methyl-3-furanthiol and 2-furfurylthiol exhibited odor activity values (OAVs) > 100 and significantly contributed to the overall aroma of LBG Baijiu.


Assuntos
Bebidas Alcoólicas/análise , Análise de Alimentos/métodos , Odorantes/análise , Enxofre/análise , Compostos Orgânicos Voláteis/análise , Cromatografia Gasosa/métodos , Furanos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Limite de Detecção , Luminescência , Olfatometria/métodos , Microextração em Fase Sólida/métodos , Compostos de Sulfidrila/análise , Compostos de Enxofre/análise , Compostos Orgânicos Voláteis/química
17.
Environ Pollut ; 252(Pt A): 409-419, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31158669

RESUMO

Understanding the spatial distribution of organic and/or inorganic contaminants is crucial to facilitate decision-making of rehabilitation strategies in order to ensure the most appropriate management of contaminated sites in terms of contaminant removals efficiencies and operating costs. For these reasons, various interpolation methods [Thiessen Polygon (TP) method, inverse of distance (IDW) method, ordinary kriging (OK), as well as sequential Gaussian simulations (SGS)] were used to better understand the spatial distribution of As, Cr, Cu, pentachlorophenol (PCP) and dioxins and furans (PCDD/F) found onto a specific industrial site. These methods do not only vary in complexity and efficiency but also lead to different results when using values coming from the same characterization campaign. Therefore, it is often necessary to evaluate their relevance by performing a comparative analysis. The results showed that ordinary kriging (OK) was a better estimator of the mean and more advanced compared to the two other methods of interpolation (TP and IDW). However, it appeared that SGS has the same power than OK but it also permitted to calculate a reliable value of the probabilities of exceeding regulatory cut-offs of contamination.


Assuntos
Monitoramento Ambiental/métodos , Distribuição Normal , Poluentes do Solo/análise , Solo/química , Análise Espacial , Arsênico/análise , Dioxinas/análise , Monitoramento Ambiental/estatística & dados numéricos , Furanos/análise , Metais Pesados/análise , Pentaclorofenol/análise
18.
Food Chem ; 295: 449-455, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174781

RESUMO

The aroma stability of fresh coffee brew was investigated during storage over 60 min, there was a substantial reduction in available 2-furfurylthiol (2-FFT) (84%), methanethiol (72%), 3-methyl-1H-pyrole (68%) and an increase of 2-pentylfuran (65%). It is proposed that 2-FFT was reduced through reversible chemical binding and irreversible losses. Bound 2-FFT was released after cysteine addition, thereby demonstrating that a reversible binding reaction was the dominant mechanism of 2-FFT loss in natural coffee brew. The reduction in available 2-FFT was investigated at different pH and temperatures. At high pH, the reversible binding of 2-FFT was shown to protect 2-FFT from irreversible losses, while irreversible losses led to the reduction of total 2-FFT at low pH. A model reaction system was developed and a potential conjugate, hydroxyhydroquinone, was reacted with 2-FFT. Hydroxyhydroquinone also showed 2-FFT was released after cysteine addition at high pH.


Assuntos
Café/química , Armazenamento de Alimentos/métodos , Furanos/química , Odorantes/análise , Compostos de Sulfidrila/química , Furanos/análise , Concentração de Íons de Hidrogênio , Compostos de Sulfidrila/análise , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
19.
Chemosphere ; 231: 173-183, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31129398

RESUMO

Our understanding of the tetrahydrofuran (THF) degradation in complex environment is limited. The majority of THF degrading genes reported are group V soluble diiron monooxygenases and share greater than 95% homology with one another. In this study, we used sole-carbon-source incubation combined with high-throughput metagenomic sequencing to investigate this contaminant's degradation in environmental samples. We identified as-yet-uncultivated microbe from the genera Pseudonocardia and fungi Scedosporium sp. (Scedosporium sp. was successfully isolated) as THF degraders as containing THF degradation genes, while microbes from the genera Bordetella, Pandoraea and Rhodanobacter functioned as main cooperators by utilizing acidic intermediates and providing anti-acid mechanisms. Furthermore, a 9387-bp THF degradation cluster designated thmX from the as-yet-uncultivated Pseudonocardia (with 6 main ORFs and with 79-93% amino acid sequence identity with previously reported clusters) was discovered. We also found a THF-degrading related cytochrome P450 monooxygenase from the genus Scedosporium and predicted its cognate reductase for the first time. All the genes and clusters mentioned above were successfully amplified from samples and cloned into the suitable expression vectors. This study will provide novel insights for understanding of THF degradation mechanisms under acid stress conditions and mining new THF degradation genes.


Assuntos
Furanos/química , Metagenoma/genética , Actinomycetales , Furanos/análise , Furanos/metabolismo , Metagenômica , Microbiota , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Fases de Leitura Aberta
20.
Chemosphere ; 231: 240-248, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31129405

RESUMO

A retrospective analysis of a number of historical medicinal grade cod liver oil samples produced in Northern Europe revealed relatively high contamination levels of PCNs, PCDD/Fs and PCBs. The total toxic equivalence (TEQ) associated with PCDD/Fs, dl-PCBs and PCNs was in the range 95-427 pg g-1 for Baltic cod liver oils and from 70 to 148 pg g-1 for oils sourced from the North Atlantic. The corresponding range for canned cod liver products (Baltic Sea) sampled in 2017 ranged from 52 to 104 pg g-1 fat (33-34 pg g-1 ww). The contribution from PCBs to the overall TEQ toxicity was around 3-6-fold higher than from PCDD/Fs and ranged from 24 to 318 pg TEQ g-1ww. The estimated summed TEQ intakes of PCDD/Fs, dl-PCBs and dl-PCNs resulting from the consumption of the daily recommended doses was highest for the Baltic cod liver oils ranging from 16 to 293 pg kg-1 body mass (bm) day-1 for an adult, 20-183 pg kg-1 bm day-1 for a teenager and 15-131 pg kg-1 bm day-1 for a child. The contribution to daily adult TEQ intake from PCNs alone, although relatively small is estimated to contribute up to 5-fold above the recent EFSA proposed TWI of 2 pg kg-1 bm. The results indicate that although currently produced fish oils may undergo rigorous purification procedures and show low contaminant levels, cod livers sourced from the Baltic and consumed locally, continue to contribute substantially to the dietary intake of these contaminants.


Assuntos
Exposição Ambiental/análise , Óleos de Peixe/análise , Contaminação de Alimentos/estatística & dados numéricos , Poluentes Químicos da Água/análise , Adulto , Criança , Dibenzofuranos Policlorados/análise , Dioxinas/análise , Exposição Ambiental/estatística & dados numéricos , Europa (Continente) , Óleos de Peixe/química , Contaminação de Alimentos/análise , Furanos/análise , Humanos , Fígado/química , Naftalenos/análise , Bifenilos Policlorados/análise , Dibenzodioxinas Policloradas/análise , Estudos Retrospectivos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA