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1.
Food Chem ; 303: 125369, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31442902

RESUMO

A well-designed yolk-shell Fe3O4@graphitic carbon (YS-Fe3O4@GC) submicroboxes with a tunable internal cavity were constructed by one-step pyrolysis strategy followed by partially etching, in which the Fe3O4 magnetic core was well confined in compartment of GC submicroboxes. The suitable internal cavity, graphitic carbon shell and large specific surface area, play great roles in improving mass transfer of analytes. Compared to its core-shell structure, the YS-Fe3O4@GC submicroboxes as dispersive magnetic solid-phase extraction (d-MSPE) materials exhibited superior enrichment performance for sulfonamides (SAs). Thus, it was applied to sensitive/simultaneous detection of trace SAs in milk and meat samples, combing with high performance liquid chromatography (HPLC). Under optimized conditions, limits of detection (LODs, 0.11-0.25 µg L-1 for milk and 0.46-2.24 µg kg-1 for meat) and recoveries (77.2-118.0%) were obtained. This work not only offers a facile strategy for the tunable fabrication of yolk-shell architecture, but also successfully affords its exploration as d-MSPE materials.


Assuntos
Análise de Alimentos , Grafite/química , Extração em Fase Sólida/métodos , Sulfonamidas/isolamento & purificação , Animais , Cromatografia Líquida de Alta Pressão , Compostos de Ferro/química , Limite de Detecção , Magnetismo , Carne/análise , Leite/química , Sulfonamidas/análise
2.
Food Chem ; 303: 125379, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446361

RESUMO

In this study, heterologous competitive antigens (HCAs) suitable for improving the sensitivity of ELISA were successfully screened based on their cross-reactivities (CRs) with 19 quinolone analogues; each containing the norfloxacin amino derivative (NOR0) coupled with bovine serum albumin (BSA) as a coating antigen. HCAs prepared with hapten analogues (CRs of 0.77%-49.92%) remarkably enhanced the sensitivity of the subsequent ELISA. ELISA sensitivity for NOR detection improved 26-fold when moxifloxacin-BSA was used as a heterologous coating antigen relative to when NOR0-BSA was used as a homologous coating antigen. This work, therefore, represents a detailed screening method to select suitable heterologous competitive antigens that improve ELISA sensitivity. Secondly, we present new theoretical tools to estimate hapten structures for use in the method, which may also be applied to improve the sensitivity of other immunoassays.


Assuntos
Antígenos Heterófilos/análise , Ensaio de Imunoadsorção Enzimática/métodos , Quinolonas/análise , Reações Cruzadas , Haptenos , Simulação de Acoplamento Molecular , Norfloxacino/análogos & derivados , Soroalbumina Bovina/química
3.
Food Chem ; 303: 125392, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446362

RESUMO

In this article, an easy and quick method based on microwave assisted acid digestion technique prior to quantification using inductively coupled plasma mass spectrometry for the analysis of heavy metals in cocoa beans, cocoa powder and chocolate was established and validated for arsenic (As), cadmium (Cd), lead (Pb), and antimony (Sb). Limit of quantification for all elements were product dependent and varies from 7.84 to 194.52 µg/kg. The recoveries of the heavy metals at 250 and 1000 µg/kg spiking levels were ranged between 96.27-108.75%, 90.43-101.97% and 89.72-106.26% for cocoa beans, cocoa powder, and chocolate, respectively. Relative standard deviation values obtained were all below 20% and the expanded uncertainty measurements for the elements were less than 25%. The analysis of real samples found that the concentration level is far from the national alarming level except for cadmium in cocoa beans.


Assuntos
Cacau/química , Fracionamento Químico/métodos , Espectrometria de Massas/métodos , Metais Pesados/análise , Micro-Ondas , Sementes/química , Antimônio/análise , Arsênico/análise , Cádmio/análise , Chocolate/análise , Chumbo/análise
4.
Food Chem ; 303: 125378, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31450176

RESUMO

This work introduces an inexpensive and user-friendly electrochemical platform for heavy metal determination in liquid food. Smart-phone connectivity, solid-state-microwave flow digestion and nano-Au-modified electrode are synchronously studied. A smart phone is adopted as the information terminal for universal purposes. A solid-state-microwave digestion device is developed to provide programmable digestion for liquid food in a digestion path. Microwave power curve and flow rate in digestion are studied and optimized. A nano-Au-modified electrode, as well as a homemade potentiostat and other electrodes, is used as a tool for electrochemical analyses. Behaviors of this method are evaluated with electrical measurement and stripping voltammetry. This method is used for sensing Cd2+, Pb2+ and Hg2+ in cow milk, orange juice and apple juice. It provides a sensitive response to ≥2 µg L-1 target ion, and shows satisfying stability and good accuracy in a task up to 72 h.


Assuntos
Técnicas Eletroquímicas/métodos , Sucos de Frutas e Vegetais/análise , Metais Pesados/análise , Leite/química , Smartphone , Animais , Cádmio/análise , Bovinos , Eletrodos , Feminino , Ouro/química , Chumbo/análise , Mercúrio/análise , Micro-Ondas
5.
Food Chem ; 303: 125395, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31454758

RESUMO

The multi-isotope calibration (MICal) is a fast and accurate calibration strategy for multi-elemental determination that uses only two solutions, (1) 50% (v v-1) sample plus 50% (v v-1) analytical blank solution, and (2) 50% (v v-1) sample plus 50% (v v-1) standard solution (containing the analytes). The calibration curves were built as a function of the intensity signals of solution 1 (y-axis) versus solution 2 (x-axis), employing the various isotopes of each monitored mass/charge. The concentration of the analytes was calculated from the slope and the concentrations of the standards added to solution 2. The validation of the method was evaluated using standard reference materials of bovine liver and bovine muscle. The recoveries varied from 87 to 113% for MICal, which were similar to the conventional standard additions calibration procedure (83 to 120%).


Assuntos
Espectrometria de Massas/métodos , Carne/análise , Animais , Calibragem , Bovinos , Isótopos , Fígado/química , Produtos da Carne/análise
6.
Food Chem ; 303: 125393, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31466028

RESUMO

Extraction of free and bound phenols from millet in acidic and basic hydrolytic conditions were compared for the first time. Acidic hydrolysis was able to extract the highest amount of total phenolic compounds (up to 178 mg/100 g) while the basic hydrolysis underestimates the phenolic concentration. Our findings pointed out for the first time that methyl ferulate is naturally present as bound phenol in millet. Response Surface Methodology was then applied to both acidic and basic hydrolytic extractive conditions: the acidic procedure, optimized in terms of extractive time and temperature and concentration of the acidic mean, gave the best results, allowing definition of Method Operable Design Region and quantitation of the total amount of phenols in millet samples in a single extractive step. This optimized method is suitable for further accurate investigations of the typical phenols of the numerous varieties of this recently re-discovered minor cereal.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Grão Comestível/química , Fenóis/análise , Hidrólise , Milhetes/química
7.
Food Chem ; 303: 125386, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31473454

RESUMO

The present work investigated the influences of ultrahigh pressure (UHP), ultrasound (US) and their combination (UHP-US) as pretreatments on properties of vacuum-freeze dried strawberry slices. During vacuum-freeze drying, drying duration and total energy consumption of UHP sample, US sample and UHP-US sample was decreased. After the UHP or US pretreatments, a* value (redness), antioxidative substances (total anthocyanin content, total flavonoid content, total phenolic content, diphenyl picrylhydrazyl (DPPH), hydroxyl (-OH) radical-scavenging assay), hardness and cross-section areas of matrix in the dried slices were significantly (P < 0.05) increased. Transverse relaxation times and peak area corresponding to free water in the pretreated samples were obviously decreased, indicating lower mobility in the pretreated samples. As compared with UHP or US individually, UHP in combination with US increased those parameters more pronouncedly. Therefore, UHP and US are promising techniques for the vacuum-freeze drying processing of strawberry products.


Assuntos
Dessecação , Conservação de Alimentos/métodos , Fragaria/química , Frutas/química , Pressão , Ondas Ultrassônicas , Antocianinas/análise , Antioxidantes/análise , Antioxidantes/química , Cor , Flavonoides/análise , Liofilização , Frutas/efeitos da radiação , Fenóis/análise , Vácuo
8.
Food Chem ; 303: 125394, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31473455

RESUMO

A simple and effective vesicle based ultrasonic-assisted extraction (UAE) method was developed for extraction of active compounds in functional food. The target analytes were determined by ultra-high performance liquid chromatography with ultraviolet detector. Surfactant vesicle was adopted as extraction solvent. Different operating conditions including the type and concentration of vesicle, extraction time and solid to liquid ratio were investigated by single-factor experiments and response surface methodology. Optimized experimental conditions were 1% (w/v) of DTAB/SDS vesicle, 20 min of extraction time and 160 mg/mL of solid to liquid ratio. The proposed method provided good linearity in the linear range of 10-1000 µg/mL with regression coefficients larger than 0.999, low limits of detection of 27.64-55.67 ng/mL, good precision with relative standard deviations below 0.35%, and satisfactory recoveries of 83.84-90.92% for tested saponins. Consequently, the proposed vesicle based UAE method was well suited for the extraction of saponins in Panax notoginseng.


Assuntos
Fracionamento Químico/métodos , Panax notoginseng/química , Saponinas/isolamento & purificação , Ultrassom , Cromatografia Líquida de Alta Pressão , Saponinas/análise
9.
Food Chem ; 303: 125374, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31473457

RESUMO

The application of a novel Pb2+ selective sensor based on the ionic imprinted polymer in determining trace levels of lead in natural water and in fruit juice was investigated using differential pulse voltammetry (DPV). The new and selective magnetic ion-imprinted polymer (Fe3O4@SiO2@IIP) was synthesized using 2-(2-aminophenyl)-1H-benzimidazole and 4-vinyl pyridine as a ligand and functional monomer, respectively. The new polymer was utilized for modifying a GCE to generate a new electrochemical sensor. Box-Behnken design (BBD) was utilized for optimizing the parameters influencing the peak current. Extremely suitable voltammetric performance was demonstrated for the electrochemical detection of lead with a low detection limit (0.05 ng mL-1), over a wide linear concentration range (0.1-80 ng mL-1). This modified electrode as a novel sensor was utilized for determining Pb(II) ions in natural water and in fruit juice with very reasonable outcomes.


Assuntos
Técnicas Eletroquímicas/métodos , Chumbo/análise , Polímeros/química , Cátions Bivalentes , Eletrodos , Compostos de Ferro/química , Chumbo/química , Limite de Detecção , Magnetismo , Dióxido de Silício/química
10.
Food Chem ; 303: 125375, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31476527

RESUMO

Urea is well-known to offer tremendous scope for sensing/diagnosing such as adulteration in dairy products or diseases in human body. This study was organized to describe and validate a new mediator-free, unsophisticated, and direct current voltage (IV)-based sensor for facile detection of urea using nanocomposites made of urease-immobilized graphene nanoplatelets and graphitized nanodiamonds. This nanocomposite displayed sensitive and direct signal in the form of current at 0 V without the need of any complex chemical reaction. This platform was highly sensitive (limit of detection of 5 µg/mL) far superior to the comparable systems introduced recently. The incorporation of graphitized nanodiamonds within the graphene nanoplatelets layers helped improve the sensitivity by a factor of three (up to 806.3 µA (mg mL-1)-1 cm-2) with 20 s response time. As such, the use of this nanocomposite was helpful in improving sensing performances with enhanced enzyme loading capacity.


Assuntos
Técnicas Eletroquímicas/métodos , Nanocompostos/química , Ureia/análise , Grafite/química , Nanodiamantes/química
11.
Food Chem ; 303: 125396, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446365

RESUMO

This study describes the determination of lead at trace levels by slotted quartz tube flame atomic absorption spectrophotometry (SQT-FAAS) after preconcentration by the help of stearic acid coated magnetic nanoparticle (SAC-MNPs) based sonication assisted dispersive solid phase extraction (SA-DSPE). SAC-MNPs were used due to their easy separation advantages by the application of external magnetic field. All extraction parameters were optimized by response surface methodology based experimental design. The experimented data was evaluated by the analysis of variance. Under the optimum conditions, about 31 folds enhancement in detection power was obtained over the conventional FAAS. The recovery results obtained for samples spiked at 60 and 120 ng mL-1 were 106.6 and 102.6%, respectively, validating the method as accurate and applicable to the red pepper matrix. The percent relative standard deviations of the results were under 5.0% even at low concentrations that established high precision for replicate extractions and instrumental readings.


Assuntos
Capsicum/química , Chumbo/análise , Chumbo/isolamento & purificação , Microextração em Fase Líquida/métodos , Magnetismo/métodos , Extração em Fase Sólida/métodos , Espectrofotometria Atômica/métodos , Contaminação de Alimentos/análise , Frutas/química , Magnetismo/instrumentação , Nanopartículas de Magnetita/química , Quartzo/química , Sensibilidade e Especificidade , Sonicação , Ácidos Esteáricos/química
12.
Food Chem ; 303: 125405, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31466029

RESUMO

The study aimed at evaluating the influence of fermented sugarcane molasses ageing on lees and the distillation process used for the production of rums. Molasses were freshly fermented or 3-months lees aged. Batch (PS: Pot Still) or continuous (CS: Coffey Still) distillation was carried out resulting in four different rum distillates. Gas chromatography and 3D-fluorescence enabled to differentiate rum distillates chemical composition according to the distillation process, regardless of the ageing on lees of fermented molasses. Differences in fluorescent PARAFAC components and volatile acids, acetals and carbonyls contents revealed the predominance of the physicochemical processes driven at the liquid-vapor interface of fermented molasses, generated by the distillation systems. Notwithstanding the distilling conditions, the long chain fatty ester content was significantly higher in the 3-months lees aged condition. Multivariate analysis highlighted that CS rum distillates were chemically more homogeneous than those obtained by PS that preserved the lees effect.


Assuntos
Bebidas Alcoólicas/análise , Destilação/métodos , Manipulação de Alimentos/métodos , Melaço/análise , Saccharum/química , Cromatografia Gasosa , Fermentação , Fatores de Tempo
13.
Food Chem ; 303: 125404, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31466033

RESUMO

Fourier transform infrared (FTIR) spectroscopy calibrations were developed to simultaneously determine the multianalytes of five artificial sweeteners, including sodium cyclamate, sucralose, sodium saccharin, acesulfame-K and aspartame. By combining the pretreatment of the spectrum and principal component analysis, 131 feature wavenumbers were extracted from the full spectral range for modelling to qualitative and quantitative analysis. Compared to random forest, k nearest neighbour and linear discriminant analysis, support vector machine model had better predictivity, indicating the most effective identification performance. Furthermore, multivariate calibration models based on partial least squares regression were constructed for quantifying any combinations of the five artificial sweeteners, and validated by prediction data sets. As shown by the good agreement between the proposed method and the reference HPLC for the determination of the sweeteners in beverage samples, a promising and rapid tool based on FTIR spectroscopy, coupled with chemometrics, has been performed to identify and objectively quantify artificial sweeteners.


Assuntos
Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Edulcorantes/análise , Aspartame/análise , Bebidas/análise , Calibragem , Cromatografia Líquida de Alta Pressão/métodos , Ciclamatos/análise , Aprendizado de Máquina , Análise de Componente Principal , Sacarina/análise , Tiazinas/análise
14.
Food Chem ; 303: 125398, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31470272

RESUMO

Roasting is an important process in cocoa production which may lead to formation of non-desirable compounds such as polycyclic aromatic hydrocarbons (PAHs). Therefore, PAH4 (sum of four different polycyclic aromatic hydrocarbons; benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) in roasted cocoa beans was determined using a modified method (combination of QuEChERS and DLLME), and quantified by HPLC-FLD. The modified method was validated and met the performance criteria required by the EU Regulation (No. 836/2011). Results show a significant (p < 0.05) increase of PAH4 (0.19-7.73 ng/g) with an increase in temperatures (110-190 °C) and duration (10-50 min). The PAHs content in whole cocoa bean roasting was detected even at the lowest temperature (110 °C) compared to nib roasting detected at 150 °C which indicates that PAHs was transferred from dried shells to roasted cocoa beans during the roasting process. The data obtained may help to control and minimize PAH4 formation during cocoa processing.


Assuntos
Cacau/química , Cromatografia Líquida de Alta Pressão/métodos , Microextração em Fase Líquida/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Antracenos/análise , Antracenos/isolamento & purificação , Benzo(a)pireno/análise , Benzo(a)pireno/isolamento & purificação , Crisenos/análise , Crisenos/isolamento & purificação , Fluorenos/análise , Fluorenos/isolamento & purificação , Sementes/química
15.
Food Chem ; 303: 125399, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31470274

RESUMO

It is still a challenge to solve the matrix interferences in veterinary drug residue analysis. In this study, we reported a thin layer chromatography (TLC)-high-performance liquid chromatography (HPLC) method for determining total florfenicol (FF) residues, expressed as florfenicol amine (FFA), in porcine edible tissues. The tissue homogenate were acid-hydrolyzed to liberate the bound residues and convert them into FFA. The hydrolysates were washed with ethyl acetate and subsequently extracted with ethyl acetate under alkaline conditions. The supernatants were concentrated through evaporation, defatted with hexane, purified by TLC and analyzed by HPLC at 225 nm. The optimal developing solvent for TLC purification was ethyl acetate-acetone-ammonium hydroxide mixtures (2:8:0.5, v/v/v). The method was fully validated according to decision 2002/657/EC, and could be used for the routine monitoring of FF residues in pig. TLC showed excellent purification efficiency, and was expected to solve the matrix interferences in veterinary drug residue analysis.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cromatografia em Camada Delgada/métodos , Resíduos de Drogas/análise , Tianfenicol/análogos & derivados , Drogas Veterinárias/análise , Estruturas Animais/química , Animais , Cromatografia Líquida/métodos , Carne/análise , Suínos , Tianfenicol/análise
16.
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
17.
Food Chem ; 303: 125414, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31473458

RESUMO

A 3D scanning method was developed to differentiate Octopus minor blocks which had surplus water to increase weight of O. minor. Effects of soaking time (0.5, 1 and 3 h) and apparent density of O. minor were determined using the number of O. minor in a block (4, 5, 6, and 7). A 0.5, 1, and 3 h soaking time increased O. minor weight by 11.85, 16.02, and 24.53%, respectively. Apparent density of non-weight gained O. minor blocks was significantly higher than those of 3 h soaked samples (p < 0.05). A 3D scanning method had limited ability to differentiate 1 h soaked and non-soaked samples, whereas it had high potential to discriminate 3 h soaked samples. Blind test using 25 blocks of O. minor showed that 3D scanning method evaluated 88% of prediction percentage. The total time of 3D scanning took <30 min for one block with a relatively high precision.


Assuntos
Imagem Tridimensional/métodos , Octopodiformes/química , Água/metabolismo , Animais , Octopodiformes/metabolismo , Água/química
18.
Food Chem ; 302: 125347, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31430631

RESUMO

This work aims to prolong the storage stability of polyphenols, obtained from grape pomace, using a spray drying-based microencapsulation technique. The microcapsules obtained under optimal conditions were stored at two different relative humidities (33% and 52%) during 75 days. The analyses of total phenolic content, antioxidant activity, and individual phenolic compounds were carried out every 15 days, and the most stable microcapsules were achieved with maltodextrin DE4-7 prepared by adding gum Arabic to the wall material at a ratio of 8:2. The phenolic content loss rate was found to be in a range of 0.93-5.42 % depending on phenolic compound. The decrease in the content of rutin, chlorogenic acid, epicatechin, caffeic acid, gallic acid, caftaric acid and catechin was only 0.93, 2.09, 2.13, 2.27, 2.41, 3.40 and 5.42%, respectively. These results indicate more efficient storage conditions than those of previously reported studies.


Assuntos
Cápsulas/química , Armazenamento de Alimentos , Polifenóis/química , Vitis/química , Antioxidantes/análise , Antioxidantes/química , Catequina/análise , Catequina/química , Ácido Clorogênico/análise , Ácido Clorogênico/química , Composição de Medicamentos/métodos , Goma Arábica/química , Umidade , Fenóis/análise , Fenóis/química , Extratos Vegetais/química , Polifenóis/análise , Polissacarídeos/química , Rutina/análise , Rutina/química
19.
Food Chem ; 302: 125371, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31437711

RESUMO

Dietary selenium deficiency is recognized as a global problem. Pork is the most widely consumed meat throughout the world and an important source of selenium for humans. In this study, a reliable approach was developed for analyzing selenium and its speciation in the muscles of pigs after different selenium treatments. The selenium source deposition efficiency was ranked as: selenomethionine > methylselenocysteine > selenite, and the muscle selenium content had a dose effect with selenomethionine supplementation. In total, four species of selenium were detected in the muscles of pigs and the distributions of these selenium species were greatly affected by the dietary selenium supplementation forms and levels. Selenomethionine (>70% of total selenium) and selenocystine (>11%) were the major selenium species, followed by methylselenocysteine and selenourea. Therefore, selenium-enriched pork produced from selenomethionine is a good source for improving human dietary selenium intake.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas/métodos , Músculo Esquelético/química , Compostos de Selênio/farmacologia , Selênio/análise , Animais , Cistina/análogos & derivados , Cistina/análise , Suplementos Nutricionais , Análise de Alimentos/métodos , Masculino , Músculo Esquelético/efeitos dos fármacos , Compostos Organosselênicos/análise , Reprodutibilidade dos Testes , Ácido Selenioso/farmacologia , Compostos de Selênio/análise , Selenocisteína/análogos & derivados , Selenocisteína/farmacologia , Selenometionina/análise , Selenometionina/farmacologia , Suínos , Ureia/análogos & derivados , Ureia/análise
20.
Food Chem ; 302: 125370, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442699

RESUMO

Four Arabica coffees (Brazil, Colombia, Ethiopia, and Guatemala) yield highly variant odours, attesting to the complexities of coffee aroma that command advanced analytical tools. In this study, their volatiles were extracted using solvent-assisted flavour evaporation (SAFE) and headspace solid-phase microextraction (HS-SPME). Due to matrix complexity, some trace odourants were detected in SAFE extracts by aroma extract dilution analysis (AEDA) but remained difficult to quantify by gas chromatography-mass spectrometry (GC-MS). This prompted the application of low energy electron ionisation (EI) coupled with GC-quadrupole time-of-flight (GC-QTOF). Optimal low EI GC-QTOF parameters (EI energy: 15 eV, acquisition rate: 3 Hz) were applied to achieve improved molecular ion signal intensity and reproducibility (relative standard deviation < 10%) across five compounds, which resulted in good linearity (R2 ≥ 0.999) and lowered detection levels (e.g. 0.025 ±â€¯0.005 ng/mL for 4-hydroxy-5-methyl-3(2H)-furanone). Therefore, this method potentially improves the measurement of trace odourants in complex matrices by increasing specificity and sensitivity.


Assuntos
Café/química , Análise de Alimentos/métodos , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Adulto , Brasil , Coffea/química , Colômbia , Etiópia , Feminino , Análise de Alimentos/estatística & dados numéricos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Guatemala , Humanos , Masculino , Pessoa de Meia-Idade , Olfatometria/métodos , Extratos Vegetais/química , Análise de Componente Principal , Reprodutibilidade dos Testes , Microextração em Fase Sólida/métodos , Paladar , Compostos Orgânicos Voláteis/isolamento & purificação
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