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1.
Chem Biol Interact ; 330: 109228, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32827518

RESUMO

This study aimed at exploring the potential mechanism of decreased in vivo exposure of the antiplatelet agent, ticagrelor and its active metabolite, AR-C124910XX, mediated by tea polyphenols, which was first revealed by our previous study, as well as predicting the in vivo drug-drug interaction (DDI) potential utilizing an in vitro to in vivo extrapolation (IVIVE) approach. The bidirectional transport and uptake kinetics of ticagrelor were determined using Caco-2 cells. Inhibition potency of major components of tea polyphenols, epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were obtained from Caco-2 cells, human intestinal and hepatic microsomes (HIMs and HLMs) in vitro. A mean efflux ratio of 2.28 ± 0.38 and active uptake behavior of ticagrelor were observed in Caco-2 cell studies. Further investigation showed that the IC50 values of EGCG and EGC on the uptake of ticagrelor were 42.0 ± 5.1 µM (95% CI 31.9-54.8 µM) and 161 ± 13 µM (95% CI 136-191 µM), respectively. EGCG and EGC also displayed moderate to weak reversible inhibition on the formation of AR-C124910XX and the inactive metabolite, AR-C133913XX in HIMs and HLMs, while no clinically significant time-dependent inhibition was observed for either compound. IVIVE indicated a significant inhibition effect of EGCG on the uptake process of ticagrelor, while no potential DDI risk was found based on microsomal data. A 45% decrease in ticagrelor in vivo exposure was mechanistically predicted by incorporating intestinal and hepatic metabolism as well as intestinal absorption. This dual inhibition of tea polyphenols on ticagrelor revealed the underlying potential of transporter-enzyme interplay, in which the altered uptake process was more critical.


Assuntos
Modelos Teóricos , Polifenóis/farmacologia , Chá/química , Ticagrelor/antagonistas & inibidores , Adenosina/análogos & derivados , Adenosina/metabolismo , Transporte Biológico/efeitos dos fármacos , Células CACO-2 , Catequina/análogos & derivados , Catequina/farmacologia , Linhagem Celular Tumoral , Interações Medicamentosas , Humanos , Absorção Intestinal/efeitos dos fármacos , Cinética , Microssomos Hepáticos/metabolismo , Inibidores da Agregação de Plaquetas/farmacocinética , Antagonistas do Receptor Purinérgico P2Y/farmacocinética , Ticagrelor/metabolismo , Ticagrelor/farmacocinética
2.
J Chromatogr A ; 1626: 461328, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797818

RESUMO

Ferric oxide/carbon (Fe2O3@C) was fabricated via direct carbonization of metal-organic framework of iron (MOF-235) under argon atmosphere. The magnetic Fe2O3 nanoparticles are evenly embedded in porous carbon matrix, while original morphology of MOF-235 was well-maintained. The synthesized Fe2O3@C was used as magnetic sorbent for extracting five benzoylurea insecticides (BUs). The materials exhibited excellent extraction performance, which benefited not only from the strong π-π interaction and hydrophobic interaction (π-conjugated system), but also to the abundant adsorption sites and flexible transport channel (the interconnected 3D porous structure). A three-factor-three-level Box-Behnken design (BBD) was selected to optimize three greatly influential parameters: amount of adsorbent (A), desorption time (B) and volume of desorption solvent (C) by response surface methodology. The established method coupled to HPLC-UV detection showed wide linearity with the range of 0.2-450 µg•L-1, relatively low limits of detection (0.05-0.10 µg•L-1) with the relative standard deviation (RSD) (n = 7) lower t than 5.47%. Moreover, the proposed method was successfully applied to analyze BUs in tea samples and investigate the removal effect of different washing on BUs residues from tea leaf. These results indicated that the synthesized Fe2O3@C is a promising adsorbent material for magnetic solid phase extraction of BUs at trace concentrations from tea samples.


Assuntos
Inseticidas/análise , Nanopartículas de Magnetita/química , Estruturas Metalorgânicas/química , Chá/química , Ureia/análise , Adsorção , Carbono/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida de Alta Pressão/normas , Compostos Férricos/química , Inseticidas/isolamento & purificação , Inseticidas/normas , Limite de Detecção , Porosidade , Padrões de Referência , Extração em Fase Sólida , Espectrofotometria Ultravioleta , Chá/metabolismo , Ureia/análogos & derivados , Ureia/isolamento & purificação , Ureia/normas
3.
Food Chem ; 332: 127392, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32623126

RESUMO

The present work describes a novel and rapid approach for evaluating total phenolic compounds (TPCs) in tea and fruits using colorimetric spots and the digital image-based (DIB) method. Colorimetric spots were formed by reacting diazotized aminobenzenes namely sulfanilic acid, sulfanilamide, or aniline with TPCs in the extract to form an azo dye. The limit of detection (LOD) was 6.5, 5.5, or 5.1 mg GAE (gallic acid equivalent) L-1 and the analytical range was 25-500, 20-500, or 18-200 mg GAE L-1, respectively. Correlation with the Folin-Ciocalteu assay was significant (Pearson coefficient, R = 0.970-0.991) while the antioxidant activity assay was moderate to high (R = 0.737-0.977). The method developed was successfully applied to the analysis of tea and fruits and showed RSD (n = 3) not exceeding 9.6, 8.5, and 9.7%, respectively. Ecologically, the DIB method developed could determine the variation of TPCs within cultivars and was found to be strongly dependent on the growing environment.


Assuntos
Benzeno/química , Colorimetria/métodos , Análise de Alimentos/métodos , Frutas/química , Fenóis/análise , Chá/química , Antioxidantes/análise , Limite de Detecção
4.
Food Chem ; 332: 127409, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615388

RESUMO

This work reports a new method to evaluate the antioxidant capacity of infusions and beverages, based on superoxide radicals. Radicals produced by the enzymatic reaction between acetylcholinesterase and hypoxanthine oxidized antioxidant molecules present in commercially available samples or standard solutions, which was monitored by means of cyclic voltammetry using a carbon paste electrode. The Trolox equivalent antioxidant capacity (TEAC) of red wine, coffee and green tea determined using this method were: (1.20 ± 0.06), (0.90 ± 0.02), and (0.65 ± 0.02), respectively. This method suggested TEACred wine > TEACcoffee > TEACgreen tea, which is the same as DPPH, spectrophotometric method. However, the electrochemical one proposed here is rapid and simple.


Assuntos
Antioxidantes/química , Bebidas/análise , Técnicas Eletroquímicas/métodos , Superóxidos/química , Antioxidantes/metabolismo , Café/química , Eletrodos , Concentração de Íons de Hidrogênio , Hipoxantina/química , Hipoxantina/metabolismo , Oxirredução , Superóxidos/metabolismo , Chá/química , Vinho/análise , Xantina Oxidase/metabolismo
5.
Food Chem ; 332: 127412, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32623128

RESUMO

In this study, metabolomics and proteomics were employed to investigate the change mechanism of nonvolatile compounds during white tea processing. A total of 99 nonvolatile compounds were identified, among which the contents of 13 free amino acids, caffeine, theaflavins, 7 nucleosides and nucleotides, and 5 flavone glycosides increased significantly, while the contents of theanine, catechins, theasinesins, 3 proanthocyanidins, and phenolic acids decreased significantly during the withering period. The results of proteomics indicated that the degradation of proteins accounted for the increase in free amino acid levels; the weakened biosynthesis, in addition to oxidation, also contributed to the decrease in flavonoid levels; the degradation of ribonucleic acids contributed to the increase in nucleoside and nucleotide levels during the withering period. In addition, the drying process was found to slightly promote the formation of white tea taste. Our study provides a novel characterization of white tea taste formation during processing.


Assuntos
Camellia sinensis/química , Metabolômica/métodos , Chá/química , Alcaloides/análise , Alcaloides/metabolismo , Camellia sinensis/metabolismo , Catecóis/análise , Catecóis/metabolismo , Flavonoides/análise , Flavonoides/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Análise de Componente Principal , Proteômica , Chá/metabolismo
6.
Food Chem ; 332: 127288, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619935

RESUMO

This study examined the effect of green tea extract at 10 (GWG1%) and 50 (GWG5%) g/L as the steeping solution on the chemical, nutritional, and microbial quality of wheat grain during 14 days of germination. Fat, dry matter, and ash contents in the control was higher than GWG treatments due to the faster growth of control germs. Moisture, phenolic compounds, thiamin, niacin, and tocopherols decreased, whereas, fat, dry matter, carbohydrate, protein, crude fiber, ash, folic acid, Ca, Mg, Fe, Mn, and Zn increased significantly in all samples during germination. GWG5% showed the highest values in total phenols, vitamins, minerals, and carbohydrate, followed by GWG1% and then the control. No significant differences in protein and crude fiber content were detected among treatments. GWG decreased the growth of total bacterial, yeast, and mold in germinated seeds. Overall, GWG improved the microbial and nutritional quality of wheat germ during 14 days of germination.


Assuntos
Germinação/efeitos dos fármacos , Valor Nutritivo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Chá/química , Triticum/metabolismo , Triticum/microbiologia , Triticum/efeitos dos fármacos
7.
Food Chem ; 333: 127432, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32659661

RESUMO

The sensory qualities and shelf life of tea beverage strongly affected by tea cream that forms by the interaction of polyphenols and protein. The study aimed to investigate the effects of the interactions between tea polyphenols (TPs) and bovine serum albumin (BSA) on tea cream formation at different concentrations. The tea cream formation increased with TPs and BSA concentration increased. The optimal concentration (TPs: 800 mg/L, BSA: 40 mg/L), for high clarities and contents of phytochemicals, was selected by the technique for order preference by similarity to ideal solution (C = 0.7572). The interaction mechanism of TPs-BSA was investigated by fluorescence spectroscopy, UV-visible absorption spectroscopy, synchronous fluorescence spectroscopy, and molecular docking. TPs interacted with BSA via static quenching process, affecting tryptophan and tyrosine residue microenvironment of BSA. Ester catechins had more binding affinity than non-ester catechins. Hydrogen bonds were the main interaction forces of TPs-BSA.


Assuntos
Polifenóis/química , Polifenóis/metabolismo , Soroalbumina Bovina/química , Chá/química , Animais , Sítios de Ligação , Catequina/química , Catequina/metabolismo , Precipitação Química , Ligação de Hidrogênio , Simulação de Acoplamento Molecular , Tamanho da Partícula , Soroalbumina Bovina/metabolismo , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Chá/metabolismo , Termodinâmica
8.
Food Chem ; 331: 127260, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32653763

RESUMO

Monitoring of tropane alkaloids is regulated in the European Union in cereal-based foods for infants and young children, tea and herbal infusions. The European Commission's Joint Research Centre (JRC) developed an improved LC-MS/MS analytical method using a pentafluorophenyl column, validated it and conducted two proficiency tests targeting these food categories. A subset of the data gathered from laboratories that used the JRC method was additionally exploited to derive interlaboratory performance characteristics. The method showed fit-for-purpose figures of merit. The LOQs for atropine and scopolamine were around 0.4 and 1.2 µg/kg in cereal products, and in tea and herbal infusions, respectively. Uncertainties varied from 15 to 25%. The reproducibility varied from 11 to 38% for scopolamine and from 17 to 44% for atropine at levels ranging from 0.18 to 18.8 and 1.2-54.0 µg/kg, respectively. Recoveries ranged from 71 to 96%. These performance parameters render the method a good candidate for standardisation.


Assuntos
Alcaloides/análise , Grão Comestível/química , Chá/química , Tropanos/análise , Alcaloides/química , Atropina/análise , Cromatografia Líquida de Alta Pressão , Humanos , Limite de Detecção , Reprodutibilidade dos Testes , Escopolamina/análise , Espectrometria de Massas em Tandem/métodos , Tropanos/química
9.
Food Chem ; 333: 127534, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32673948

RESUMO

A new kind of multi-component membrane was prepared by combining gelatin solution, porogen and an inclusion complex of ionic liquid (IL) and beta-cyclodextrin (ß-CD) in a simple physical manner for selective separation of tea polyphenols (TPs) from green tea crude extracts. After screening, it was found that the resulting membrane containing the IL of dicationic N-vinylimidazole proline salt ([VIm]2C3[l-pro]2) had the excellent performance for the enrichment of the target molecules. Then the newly-developed film was comprehensively characterized by scanning electron microscopy, conductivity, thermogravimetry and spectral analysis. Under pressure driving, the adsorption from an aqueous solution of a mixture of TPs and theophylline on IL@ß-CD-Gel membrane showed that the adsorption capacity for TPs was 303.45 mg/g with removal percentages of 94.38%. The experimental data fit well with pseudo-second-order model and Freundlich model. By using this composite material, a new technology of membrane separation for selective adsorption of TPs was finally established.


Assuntos
Fracionamento Químico/métodos , Gelatina/química , Líquidos Iônicos/química , Membranas Artificiais , Polifenóis/isolamento & purificação , Chá/química , beta-Ciclodextrinas/química , Polifenóis/análise
11.
Food Chem ; 329: 127159, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32497845

RESUMO

The widespread use of neonicotinoids (NEOs) and fipronils (FIPs) as insecticides in modern agriculture has been widely investigated because of their adverse effects on human health. This study aimed to develop an accurate quantitative approach to analyze NEOs and FIPs in tea by using a modified QuEChERS method based on dispersive solid-phase extraction procedure coupled with liquid chromatography-high resolution mass spectrometry. To minimize matrix interferences largely, we selected polyvinylpolypyrrolidone (PVPP) and strong cationic exchange adsorbent (PCX) as dispersive adsorbents to eliminate polyphenols and caffeine from tea extract, respectively. Under optimal conditions, a slight matrix effect was observed for NEOs and FIPs due to the highest reductions of polyphenols and caffeine (94% and 88%, respectively). The method was validated by the European Medicines Agency and Eurachem guidelines and was successfully applied to tea samples for NEOs and FIPs analysis. NEOs and FIPs were commonly detected in tea.


Assuntos
Contaminação de Alimentos/análise , Neonicotinoides/análise , Pirazóis/análise , Chá/química , Cafeína/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Inseticidas/análise , Polifenóis/química , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
12.
J Chromatogr A ; 1623: 461204, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505292

RESUMO

Deep eutectic solvents (DESs) were used as an extractant for the determination of pyrethroids in environmental water and tea beverage samples. Three different acids were chosen as hydrogen bond donors for preparation of DESs, and decanoic acid was optimal because of its high recovery. Factors affecting relative recovery were optimized individually, including salt addition, surfactant addition, extraction temperature, DES amount, and sample volume etc. Under the optimized experimental conditions, the relative recovery of pyrethroids was from 89.3% to 97.7%, with relative standard deviation (RSD) values ranging from 1.75% to 2.73%. The linear correlation coefficient ranged from 0.9981 to 0.9992, and the linear range was between 1.9 and 500 µg/L. Based on a signal-to-noise ratio (S/N) of 3:1, the limit of detection (LOD) values were 0.56 to 1.24 µg/L. The enrichment factor ranged from 92 to 105. In conclusion, good extraction efficiency was achieved in tea beverage samples under the optimized conditions.


Assuntos
Bebidas , Emulsões/química , Interações Hidrofóbicas e Hidrofílicas , Microextração em Fase Líquida/métodos , Piretrinas/análise , Solventes/química , Chá/química , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Cloreto de Sódio/química , Tensoativos/química , Temperatura , Água/química
13.
Niger J Clin Pract ; 23(6): 783-791, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32525112

RESUMO

Background: Microorganisms in the mouth are protected from negative environmental conditions by forming biofilms; however, the use of anti-plaque agents in children is not preferred due to toxic side effects. Green tea has been reported to have anti-microbial and anti-dental caries properties. Aims: The aim of this study was to assess the ability of green tea extract to prevent the formation of biofilm on the teeth of children using space maintainers. Methods: Bacteria were isolated from samples obtained from children aged between 8 and 10 years. The micro-titer plate method and Congo red agar were used to assay biofilm formation. Green tea leaves were obtained from Rize, Turkey. Methanol, hexane and distilled water were used for preparing the extracts. The effects of green tea extract and chlorhexidine on biofilm formation were examined using scanning electron microscopy. Results: Presence of S. mutans 3,3, S. anginosus 2.1.b, S. dysgalactie 6.1.4.1, and E. faecium 10.2. was measured in the biofilm samples. The extracts showed a bacteriostatic effect on the test bacteria, and among the green tea extracts, the methanol extract was found to exhibit the highest efficacy against biofilm formation by S. mutans 3.3. Conclusion: Green tea extract showed good efficacy in controlling bacterial growth, and is recommended as a better-tasting alternative for daily oral hygiene due to a lack of known side effects.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Clorexidina/farmacologia , Cárie Dentária/microbiologia , Braquetes Ortodônticos/microbiologia , Extratos Vegetais/farmacologia , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus mutans/efeitos dos fármacos , Chá/química , Antioxidantes/farmacologia , Carga Bacteriana/efeitos dos fármacos , Criança , Cárie Dentária/tratamento farmacológico , Humanos , Metanol , Testes de Sensibilidade Microbiana , Boca , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Solventes/química , Streptococcus mutans/isolamento & purificação , Streptococcus mutans/fisiologia , Turquia
14.
Food Chem ; 329: 127210, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512388

RESUMO

In this study, a novel, easy, rapid and green zirconium nanoparticles (Zr-NPs) based dispersive solid phase extraction (DSPE) method is presented for the precise and sensitive determination of selenium by slotted quartz tube-flame atomic absorption spectrophotometry (SQT-FAAS). Influential parameters of the extraction procedure were optimized by altering one parameter while keeping the other parameters constant. The optimum conditions were selected as 10 mg of Zr-NPs, 75 s vortex period, and 200 µL of concentrated HCl for 30 mL of sample/standard solution. The linear range of the developed method was found to be between 25 and 100 µg/L, and the respective limits of detection and quantification were 5.3 and 18 µg/L. About 415 folds enhancement in detection power was achieved by the optimized method relative to the conventional FAAS. Green tea samples were spiked and used for recovery experiments and the results obtained were between 92 and 102%.


Assuntos
Nanopartículas Metálicas/química , Selênio/análise , Espectrofotometria Atômica/métodos , Chá/química , Zircônio/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Reprodutibilidade dos Testes , Selênio/isolamento & purificação , Extração em Fase Sólida
15.
Food Chem ; 329: 127177, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512396

RESUMO

Carmine is an artificial colorant commonly used by fraudulent food business participants in black tea adulteration, for purpose of gaining illegal profits. This study combined spectrophotometry with machine learning for rapid detection of carmine in black tea based on the spectral characteristics of tea infusion. The qualitative model demonstrated an accuracy rate of 100% for successful identification of the presence/absence of carmine in black tea. For quantitative analysis, the R2 between carmine concentrations generated according to spectral characteristics and those determined with HPLC was 0.988 and 0.972, respectively, for black tea samples involved in the test subset and an independent dataset II. Paired t-test indicated that the difference was statistically insignificant (P values of 0.26 and 0.44, respectively). The method established in this study was rapid and reliable for detecting carmine in black tea, and thus could be used as a useful tool to identify black tea adulteration in market.


Assuntos
Carmim/análise , Chá/química , Camellia sinensis , Cromatografia Líquida de Alta Pressão , Análise de Alimentos , Espectrofotometria , Chá/metabolismo
16.
Food Chem ; 330: 127212, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32526650

RESUMO

In this work, a facile solid phase extraction (SPE) method was developed for the analysis of trace Pb2+ and Cd2+ by using chitosan/thiol modified metal-organic frameworks (CS/MOF-SH) composite as adsorbent followed by graphite furnace atomic absorption spectrometer (GF-AAS) detection. The potential influencing factors, such as solution pH, adsorbent dosage, and extraction time, were fully estimated. Under the optimized extraction conditions, the detection limits of Pb2+ and Cd2+ were 0.033 µg L-1 and 0.008 µg L-1, respectively. Compared to other studies, CS/MOF-SH not only possessed superior adsorption performance, but also had the advantages of ease of handling and recyclability. Encouragingly, the developed method was of high accuracy and could monitor trace Pb2+ and Cd2+ in various certified reference materials (rice, wheat and tea) with complicated matrices, demonstrating its practical potential for regular monitoring of trace heavy metal ions in real food samples.


Assuntos
Cádmio/análise , Quitosana/química , Chumbo/análise , Estruturas Metalorgânicas/química , Compostos de Sulfidrila/química , Cádmio/química , Cátions Bivalentes , Análise de Alimentos , Chumbo/química , Oryza/química , Extração em Fase Sólida/métodos , Chá/química , Triticum/química
17.
Food Chem ; 331: 127258, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32544652

RESUMO

Flavor stability is important for the quality of tea beverages. Baking is a typical processing technology to improve the flavor of tea leaves. In present study, seven raw tea materials, including steamed spring and autumn tea leaves, pan-fired spring tea leaves, and their corresponding baked tea leaves, were used to investigate the effect of baking on flavor stability of green tea beverages. The results showed that tea beverages prepared with baked tea had better flavor stability. The baking process obviously changed the concentrations of some important flavor substances, especially the aromatic pyrrole substances from 0 (unbaked) to 338.13 µg/L (baked) in tea beverages. Heat treatment had little influence on the flavor of tea beverages prepared from baked tea, but caused great changes in non-volatile and volatile components in those prepared from unbaked leaves. These results could help guide the processing of tea beverages which would improve their flavor quality stability.


Assuntos
Bebidas/análise , Manipulação de Alimentos/métodos , Chá/química , Catequina/análise , Cromatografia Líquida de Alta Pressão , Cor , Espectrometria de Massas , Folhas de Planta/química , Folhas de Planta/metabolismo , Polifenóis/análise , Análise de Componente Principal , Paladar , Chá/metabolismo , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
18.
Food Chem ; 328: 127113, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32474239

RESUMO

In view of the high polarity and ubiquitous occurrence of perchlorate, achieving an ultra-trace analysis has become a challenging task. The present study aimed to develop a simple and generic pretreatment protocol based on cold-induced liquid-liquid extraction to efficiently extract perchlorate from tea and dairy products and remarkably decrease potential matrix interferences and laborious cleanup. By optimizing the pretreatment conditions, the enrichment factor of perchlorate increased by 7.79 times under the compromise between the matrix effect and extraction recovery. The validated method presented satisfactory selectivity, linearity, accuracy, precision, and matrix effect, providing recoveries of 78.2%-106.2% with RSDr ranging from 1.2% to 7.9% and RSDR less than 10.7% for tea and dairy products. This pretreatment protocol depended only on shaking, freezing, and centrifugation in one step, without additional equipment or tedious operations, which will be explored to a greater extent in complex biological or food matrices.


Assuntos
Laticínios/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Extração Líquido-Líquido/métodos , Percloratos/análise , Chá/química , Centrifugação/métodos , Análise Custo-Benefício , Análise de Alimentos/economia , Congelamento , Extração Líquido-Líquido/economia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fatores de Tempo
19.
Food Chem ; 326: 127028, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32428857

RESUMO

One interesting phenomenon of Chrysanthemum morifolium tea is its formation of a green or dark green color after hours of brewing, and it is important to study the compounds that form this color and whether they might be involved in health benefits. Non-targeted metabolomics could clearly distinguish between green and non-green species by sparse partial least squares discriminant analysis (sPLS-DA) and heat-mapping. We found that the pH was the primary factor in the formation of the green color. Two green precursors (GP1 and GP2) were separated and purified with preparative HPLC. FT-IR analysis and the saccharide content analysis showed that GP1 had the typical characteristics of saccharides. GP2 was identified as chlorogenic acid by ESI-Q-TOF/MS and NMR. We raised the formation process of green substances was caused by the hydrolysates of chlorogenic acid reacting with glycosides or groups attached to the saccharides, which suggests a new mechanism for color-forming reactions.


Assuntos
Chrysanthemum/química , Chá/química , Cromatografia Líquida de Alta Pressão , Cor , Flores/química , Glicosídeos/análise , Análise dos Mínimos Quadrados , Extratos Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier
20.
J Chromatogr A ; 1622: 461131, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32381301

RESUMO

A carbazolic conjugated microporous polymer (designated as CZ-CMP) was successfully synthesized through Scholl reaction of carbazole with 1, 3, 5-triphenylbenzene. The CZ-CMP was characterized by FT-IR spectrum, X-ray diffraction, nitrogen sorption isotherms, and scanning electron microscopy. The characterization results showed that the CZ-CMP had a spherical structure with high surface area and good microporosity. Its adsorption performance was investigated by applying it as an adsorbent for the solid phase extraction (SPE) of phenyl urea herbicides (PUHs) (metoxuron, chlortoluron, isoproturon, monolinuron and buturon) from tea drinks samples prior to high performance liquid chromatographic detection. The CZ-CMP displayed high extraction efficiency for the PUHs, and the primary factors affecting the SPE efficiency including the type and volume of the eluent, sample solution pH, sample loading rate and sample volume were optimized. Under the optimized conditions, a good linear response for the analytes was observed in the range of 0.10-80.0 ng mL-1 with correlation coefficients (r) from 0.9937 to 0.9997. The limits of detection were measured to be in the range of 0.02-0.30 ng mL-1 and the limits of quantitation were in the range of 0.06-0.9 ng mL-1. The developed method was successfully applied for the determination of the five PUHs in four different kinds of drinks with the method recoveries between 83.7% and 118% and the relative standard deviations between 1.0% and 10%. Besides, the application potential of the CZ-CMP was evaluated by using it to extract different types of the organic compounds including some phthalate eaters (PAEs), chlorophenol (CPs), nitroimidazoles and polycyclic aromatic hydrocarbons (PAHs). The results indicated that the CZ-CMP had strong adsorption ability for the compounds with more hydrogen bonding sites and moderate hydrophobicity.


Assuntos
Herbicidas/isolamento & purificação , Compostos de Fenilureia/química , Polímeros/síntese química , Extração em Fase Sólida/métodos , Adsorção , Carbazóis/química , Cromatografia Líquida de Alta Pressão/métodos , Concentração de Íons de Hidrogênio , Compostos de Fenilureia/isolamento & purificação , Polímeros/química , Porosidade , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Chá/química
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