Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 789
Filtrar
1.
Food Chem ; 307: 125548, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31654949

RESUMO

Due to their high content of ß-glucan, the consumption of oat products can contribute to a healthy diet. Roasting may improve sensory properties but could also affect the nutritional value of oat products. Therefore, the aim of the present study was to analyse the impact of different roasting conditions (140-180 °C, approx. 20 min) on sensory quality, health-related compounds (e.g. acrylamide, ß-glucan) and viscosities of oat kernels and flakes. Roasting resulted in oat flakes with improved sensory properties. Acrylamide formation increased with higher roasting temperatures in kernels, thin and thick flakes. Contents of fat, protein, starch and ß-glucan were not affected by roasting, whereas dietary fibre fractions were marginally modulated. Viscosities were significantly reduced with increasing roasting temperatures. The results indicate that roasting up to 160 °C is a processing technique with potential to generate oat products with improved sensory quality and favourable nutritional composition.


Assuntos
Avena/química , Acrilamida/química , Avena/metabolismo , Fibras na Dieta , Saúde , Temperatura Alta , Amido/química , Amido/metabolismo , Viscosidade , beta-Glucanas/química , beta-Glucanas/metabolismo
2.
Environ Sci Pollut Res Int ; 26(25): 25641-25655, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267395

RESUMO

A composite polymer, hydroxyapatite/poly(acrylamide-acrylic acid), was synthesized by gamma-induced polymerization. The factors affecting the sorption process were evaluated. The removal increased with time and achieved equilibrium after 1 h for all initial concentration ranges (10-50 mg/L). The highest removal of Sr(II) was achieved using 50 mg/L at pH 6. The sorption process was found to follow a pseudo-first-order mechanism. The equilibrium data are best described by the Langmuir model, with a monolayer capacity of 53.59 mg/g. The values of thermodynamic parameters indicate that the sorption process is endothermic (ΔH > 0), increases randomness (ΔS > 0) and is spontaneous (ΔG < 0). The results imply that the composite could be used as a promising low-cost material for the removal of radionuclides from radioactive waste.


Assuntos
Acrilatos/química , Resinas Acrílicas/química , Durapatita/química , Estrôncio/análise , Acrilamida/química , Íons , Cinética , Resíduos Radioativos , Estrôncio/química , Termodinâmica
3.
Eur J Med Chem ; 180: 62-71, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31301564

RESUMO

Oxidative stress and inflammation are major causes of numerous life-threatening human diseases. In the present study, we synthesized a series of phenylacrylamide derivatives as novel anti-oxidant and anti-inflammatory agents. Biological evaluation showed that compound 6a could more potently protect HBZY-1 mesangial cells from H2O2-caused oxidative stress than positive controls resveratrol and sulforaphane by dose- and time-dependently impairing the ROS accumulation. Preliminary anti-oxidant mechanism studies indicated that compound 6a could activate Nrf2 and increase the protein and mRNA expression of downstream anti-oxidant enzymes, ie. NQO-1, HO-1, GCLM and GCLC. Notably, 6a could inhibit the production of NO and the activity of NF-κB in LPS-stimulated HBZY-1 mesangial cells, indicating its potential anti-inflammatory activity. Interestingly, both effects could be significantly attenuated by Nrf2 inhibitor TRG, HO-1 inhibitor ZnPP or GCL inhibitor BSO at non-toxic concentrations, confirming that the anti-oxidant and anti-inflammatory activity of 6a is related to the activation of Nrf2 signaling pathway. These results, together with the relatively safety profile, indicated that compound 6a could be a promising lead to develop novel anti-oxidant and anti-inflammatory agents, thus preventing diseases induced by oxidative stress and inflammation.


Assuntos
Acrilamida/farmacologia , Anti-Inflamatórios não Esteroides/farmacologia , Antioxidantes/farmacologia , Inflamação/tratamento farmacológico , Acrilamida/síntese química , Acrilamida/química , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/química , Antioxidantes/síntese química , Antioxidantes/química , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Células HEK293 , Humanos , Peróxido de Hidrogênio/antagonistas & inibidores , Peróxido de Hidrogênio/farmacologia , Estrutura Molecular , Estresse Oxidativo/efeitos dos fármacos , Relação Estrutura-Atividade
4.
J Sci Food Agric ; 99(14): 6482-6489, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31294827

RESUMO

BACKGROUND: The presence of acrylamide in food has attracted wide attention and has raised concerns due to its potential toxic and carcinogenic effects. The phenolic compounds in buckwheat display strong antioxidant activity, which may affect the acrylamide levels. The aims of this study were to evaluate the effect of buckwheat extracts on acrylamide formation and the quality of the bread, and to investigate possible inhibitory mechanisms. RESULTS: The extracts from Tartary buckwheat seeds, Tartary buckwheat sprouts, common buckwheat seeds, and common buckwheat sprouts reduced acrylamide level in bread by 23.5, 27.3, 17.0, and 16.7%, respectively. In addition, all four buckwheat extracts significantly (P < 0.05) reduced acrylamide levels in the asparagine / glucose system. There were significant positive correlations between total phenolic compound content, the antioxidant activity of the extracts, and the reduction in the acrylamide level. Evaluation of the organoleptic and textural properties indicated that the addition of the extracts did not significantly affect the crust color, aroma, taste, crumb appearance, and hardness of the bread. CONCLUSION: This study showed that proper use of buckwheat extracts can reduce acrylamide levels in bread without having a significant impact on their properties. The study also revealed that a possible acrylamide formation inhibitory mechanism involved the Maillard reaction through the asparagine / glucose pathway. The study also provided useful information for the further application of buckwheat in improving food safety. © 2019 Society of Chemical Industry.


Assuntos
Acrilamida/química , Pão/análise , Fagopyrum/química , Aditivos Alimentares/química , Extratos Vegetais/química , Asparagina/química , Culinária , Temperatura Alta , Humanos , Reação de Maillard , Fenóis/química , Controle de Qualidade , Sementes/química , Paladar
5.
Food Chem ; 297: 125008, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253286

RESUMO

The formation of toxic and potentially carcinogenic acrylamide, alongside volatile aroma compounds, was studied after polyphenols ((+)-catechin, quercetin, gallic, ferulic, caffeic acids) were added to model bread. The addition of as little as 0.1% polyphenols to bread significantly reduced acrylamide (16.2-95.2%). In the case of quercetin, a promoting effect was observed (+9.8%) when its concentration increased. Of all the phenolic compounds, regardless of concentration, ferulic acid showed the highest level of acrylamide inhibition. This is probably due to the presence of 4-vinylguaiacol, a degradation derivative with strong antioxidant activity in heterogeneous systems. Although the phenolic compounds mitigate acrylamide, this adversely affected bread volatile profile. At the highest level (2.0%), caffeic acid most significantly suppressed Maillard-type volatiles (75.9%), followed by gallic acid (74.3%), ferulic acid (65.6%), (+)-catechin (62.4%), and quercetin (59.3%). Among polyphenols, ferulic acid decreased yeast fermentation products level the most (33.1%), simultaneously enhancing lipid oxidation product, probably due to inhibition of amylases and yeast activity.


Assuntos
Acrilamida/química , Pão/análise , Polifenóis/química , Triticum/metabolismo , Compostos Orgânicos Voláteis/química , Acrilamida/análise , Antioxidantes/química , Análise por Conglomerados , Ácidos Cumáricos/química , Cromatografia Gasosa-Espectrometria de Massas , Reação de Maillard
6.
J Agric Food Chem ; 67(27): 7598-7608, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31199637

RESUMO

So far, the effects of the semi-interpenetrating polymer network (semi-IPN) composites with functions of both nutrient slow-release and water retention on soil physicochemical properties, yield, and quality of crops have not been studied. In Part 1 of this paper ( Song, J.; Zhao, H.; Zhao, G.; Xiang, Y.; Liu, Y. J. Agric. Food Chem. 2019 , DOI: 10.1021/acs.jafc.9b00888 ), superabsorbent polymers SAPWS (grafting wheat straw (WS) to poly(acrylic-co-acrylamide), which is WS-g-P(AA-co-AM)) and SAPHEC (HEC (hydroxyethyl cellulose)-g-P(AA-co-AM)), and their semi-IPN nanocomposites SI-PSRF/SAPWS and SI-PSRF/SAPHEC (formed by chemical bonding of SAPWS or SAPHEC with PSRF (NPK-containing polymeric slow-release fertilizer)) were prepared, and their microstructures and degradation performances were systematically studied. In this study, effects of these two nanocomposites on soil physicochemical properties, crop yield, and quality as well as soil fertility, especially the relationships between these effects and the degradation performances of the materials themselves, were investigated by a pot experiment of the tomato. Results show that SI-PSRF/SAP nanocomposites can regulate the pH values of weak alkaline soils close to 7.0. The changes of soil pH values, in our study, are basically synchronized with the degradation rates of SI-PSRF/SAP, the higher the degradation rate of SI-PSRF/SAP, the lower the pH value of the alkaline soil treated. Compared with PSRF+SAP (the simple physically mixed system of PSRF and SAP) and PSRF, during the whole growth period of the tomato, SI-PSRF/SAP treatments have the lowest nitrogen release amounts, 4.74 g for SI-PSRF/SAPWS and 4.88 g for SI-PSRF/SAPHEC, the highest nitrogen contents of soils after day 40, and the highest nitrogen contents of plants on day 100, 1.16 and 1.68 g for SI-PSRF/SAPWS and 1.26 and 1.86 g for SI-PSRF/SAPHEC. While for PSRF+SAPWS, PSRF+SAPHEC, and PSRF, they are 5.16 g, 0.81 g, 0.63 g and 5.26 g, 0.87 g, 0.66 g and 5.17 g, 0.63 g, 0.52 g, respectively. There is a significant positive correlation between the material degradation rates and their nitrogen release amounts in this study, while SI-PSRF/SAP systems have the highest correlation coefficient, 0.950. In addition, compared to the control blank, the SI-PSRF/SAP system significantly increases tomato yield, 270.1% for SI-PSRF/SAPWS and 301.7% for SI-PSRF/SAPHEC. Compared with PSRF+SAP, the SI-PSRF/SAP system can make the soil treated become a high-quality soil by influencing the soil pH value, conductivity, cation exchange capacity, and the contents of nitrogen, phosphorus, organic carbon, and active organic carbon, which have significant impact on the soil quality. The chemical-bonded functional nanocomposites with a semi-IPN three-dimensional network structures formed by hydrogen-bonding interactions among functional groups of their components can more efficiently improve soil fertility, increase soil nutrient supply capacity, and promote plants growth and development as well as solve the environmental pollution caused by traditional fertilizers. The technology reported in this paper is simple and feasible for large-scale production of fertilizer with both water retention and nutrient slow-release, even nanofertilizer, which has great application potential.


Assuntos
Fertilizantes , Frutas/crescimento & desenvolvimento , Lycopersicon esculentum/crescimento & desenvolvimento , Nanocompostos/química , Solo/química , Água/química , Acrilamida/química , Resinas Acrílicas/química , Fenômenos Químicos , Produtos Agrícolas/crescimento & desenvolvimento , Preparações de Ação Retardada , Fertilizantes/análise , Qualidade dos Alimentos , Frutas/metabolismo , Ligações de Hidrogênio , Concentração de Íons de Hidrogênio , Nitrogênio/análise , Nutrientes/metabolismo , Fósforo/análise , Polímeros , Triticum
7.
Food Chem ; 296: 94-99, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31202312

RESUMO

The potential synergistic effects of Flavan-3-ols to inhibit the formation of acrylamide have attracted wide attention. This study aims to investigate the synergistic inhibitory effects of the B-type procyanidin and flavan-3-ols monomer on acrylamide production in food matrix. By comparing the inhibitory effects of different compounds in food matrix, procyanidin B2 and catechin were screened out for examining their synergistic inhibitory effects on acrylamide by Isobologram analysis. When the interaction index (γ) was lower than 1, the interaction was synergistic reaction. The results showed the procyanidin B2/catechin ratio of 1:3 (γ = 0.57) had similar synergistic effect to that of 1:9 (γ = 0.53), both of which showed better effects than the ratio of 1:1 (γ = 0.71). The optimal synergistic inhibitory effect (70.11 ±â€¯2.07%) was achieved when the procyanidin B2 and catechin concentrations were 0.6 µg/mL and 5.4 µg/mL, respectively. Compared with single use, the combined use of B2 and catechin could decrease the dosage of B2 to 1/10 and that of catechin to 1/3.


Assuntos
Acrilamida/química , Biflavonoides/química , Catequina/química , Análise de Alimentos , Proantocianidinas/química , Dimerização , Sinergismo Farmacológico
8.
Food Chem Toxicol ; 130: 308-316, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31102675

RESUMO

A total diet study (TDS) was conducted between 2010 and 2016 to assess the risk associated with chemicals in food of non-breast-fed children from 1 to 36 months living in France. Food samples were collected, prepared "as consumed", and analyzed for chemicals of public health interest. Acrylamide, furan and polycyclic aromatic hydrocarbons (PAHs) were analyzed as heat-induced compounds produced mainly during thermal processing of foods. Dietary exposure was assessed for 705 representative children using food consumptions recorded through a 3-consecutive-days record. As all calculated margins of exposure (MOE) for PAHs exceeded 10 000, dietary exposure of the infant and toddler population was deemed tolerable with regard to the carcinogenic risk. Conversely, the exposure levels to acrylamide and furan were considered as of concern, requiring management measures to reduce the exposure essentially by reducing the formation of heat-induced compounds during food production or preparation processes. Efforts should mainly focus on major contributors to the exposure, i.e. sweet and savoury biscuits and bars, and potatoes and potato products for acrylamide, baby jars of vegetables, with or without meat or fish for acrylamide and furan.


Assuntos
Acrilamida/química , Armazenamento de Alimentos , Furanos/química , Temperatura Alta , Alimentos Infantis/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Acrilamida/toxicidade , Contaminação de Alimentos , França , Furanos/toxicidade , Humanos , Lactente , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Fatores de Risco
9.
Talanta ; 199: 507-512, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30952291

RESUMO

Black phosphorus quantum dots (BPQDs) can react with Ru(bpy)32+ to generate strong anodic electrogenerated chemiluminescence (ECL). However, the instability and the lack of functional groups on BPQDs limit its further application in the fabrication of ECL biosensor. In the present work, uniform BPQDs-styrene-acrylamide (St-AAm) nanospheres (BSAN) are synthesized by encapsulating BPQDs into St-AAm copolymer nanospheres. Sufficient amount of BPQDs can be embedded into nanospheres, and react with Ru(bpy)32+ to generate strong anodic ECL which is comparable to that of pure BPQDs. Amino group of polymer endows BPQDs the ability to connect with DNA, and can be used to fabricate ECL aptasensor for the sensitive detection of lysozyme. The proposed aptasensor shows high sensitivity, good selectivity and stability for the detection of lysozyme in the range of 0.1-100 pg mL-1 with a detection limit of 0.029 pg mL-1 (3σ). The proposed method reveals the promising ECL sensing application of BP nanomaterials in the detection of various proteins.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais , Medições Luminescentes , Muramidase/análise , Pontos Quânticos/química , Acrilamida/química , Clara de Ovo/química , Muramidase/metabolismo , Nanoestruturas/química , Fósforo/química , Polímeros/química , Estireno/química
10.
Int J Biol Macromol ; 133: 964-970, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31004636

RESUMO

Porous grafted copolymer with excellent thermal stability and swelling capacity was synthesized from water soluble Prunus cerasifera gum polysaccharide (PG) and acrylamide (AM). The monosaccharide compositions and the structure of Prunus cerasifera tree gum were detected by a high-performance anion exchange chromatography (HPAEC) system and 1H NMR and 13C NMR, and the obtained PG-AM copolymer was characterized by Fourier transform infrared (FT-IR), scanning electron microscope (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The results indicated that the water soluble polysaccharides obtained from Prunus cerasifera tree gum were mainly composed of l-arabinose (39.78%) and d-galactose (40.59%) with minor amount of xylose, mannose and uronic acids. The maximum percent and the grafting efficiency of grafting acrylamide (AM) onto PG to form PG-AM were obtained by copolymerization between polysaccharide and 3 times (weight) acrylamide with 3 mmol/L potassium persulfate initiator at 50 °C for 1 h. In addition, lots of isolated and conjoint pores were observed in the prepared PG-AM materials, with a diameters distribution between 2 and 10 µm. Compared with PG, the synthesized copolymer PG-AM showed an excellent performance in thermal stability and swelling capacity. The detailed structural characteristic together with excellent thermal stability and swelling properties will benefit efficient utilization of the synthesized copolymer as a precursor for preparation of large-scale environmentally friendly advanced materials with various potential applications.


Assuntos
Gomas Vegetais/química , Polimerização , Polissacarídeos/química , Polissacarídeos/síntese química , Prunus domestica/química , Acrilamida/química , Técnicas de Química Sintética , Monossacarídeos/análise , Porosidade , Temperatura Ambiente , Ácidos Urônicos/análise
11.
Colloids Surf B Biointerfaces ; 179: 445-452, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31005739

RESUMO

This paper focuses on the development of a drug delivery system for systemically controlled release of a poorly soluble drug, letrozole. The work meticulously describes the preparation and characterizations of 2-hydroxyethyl methacrylate (HEMA) polymerization onto hydrophilic acrylamide grafted low-density polyethylene (AAm-g-LDPE) surface for targeted drug release system. The surface morphology and thickness measurement of coated pHEMA layer were measured using scanning electron microscopy (SEM). The swelling study was done in deionized (DI) water and simulated uterine fluid (SUF, pH = 7.6). In vitro release of letrozole from the system was performed in SUF. Further, the release kinetics of letrozole from the system was studied using different mathematical models. The results, suggest that the rate of drug release can be altered by varying the concentrations of cross-linker in pHEMA. The optimized sample released 72% drug at the end of 72 h of measurement.


Assuntos
Acrilamida/química , Liberação Controlada de Fármacos , Endometriose/tratamento farmacológico , Letrozol/uso terapêutico , Polietileno/química , Poli-Hidroxietil Metacrilato/química , Animais , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Cinética , Letrozol/farmacologia , Camundongos , Células NIH 3T3 , Polimerização , Porosidade
12.
Food Chem ; 290: 246-254, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31000044

RESUMO

Whether caseinate oligochitosan-glycation of the transglutaminase-type followed by trypsin digestion could lead to better protection against the acrylamide-induced cell barrier damage was investigated. Compared with caseinate digest, glycated caseinate digest had similar amount of Lys and Arg but lower -NH2 (0.557 versus 0.508 mol/kg protein) and total amide (1.12 versus 1.05 mol/kg protein) contents, and contained glucosamine at 5.74 g/kg protein. Acrylamide damaged barrier function of IEC-6 cells efficiently, leading to increased paracellular permeability and lactate dehydrogenase release, decreased trans-epithelial electrical resistance, and destroyed tight junction. The two digests alleviated these barrier dysfunctions via reversing index values. Three cellular proteins (ZO-1, occludin, and claudin-1) crucial to tight junction were up-regulated by the two digests. Furthermore, glycated caseinate digest was always more effective than caseinate digest to improve cell barrier function. This oligochitosan glycation is thus desired, as it ensures glycated protein digest with higher potential to protect intestinal barrier function.


Assuntos
Acrilamida/química , Caseínas/metabolismo , Quitina/análogos & derivados , Acrilamida/toxicidade , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Quitina/química , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Glicosilação , Humanos , Mucosa Intestinal/citologia , Ocludina/genética , Ocludina/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Peptídeos/farmacologia , Permeabilidade/efeitos dos fármacos , Substâncias Protetoras/química , Substâncias Protetoras/metabolismo , Substâncias Protetoras/farmacologia , Ratos , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo
13.
J Agric Food Chem ; 67(17): 4923-4930, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30969769

RESUMO

This study investigated the formation of Maillard reaction products in sesame seeds under different roasting conditions. Sesame seeds were roasted at 150, 180, 200, and 220 °C for 10 min, and thermal process contaminants including 5-hydroxymethylfurfural, acrylamide, furan, and dicarbonyl compounds (1-deoxyglucosone, 3-deoxyglucosone, methylglyoxal, and diacetyl) together with glycation markers namely N-ε-fructosyllysine, N-ε-carboxymethyllysine, and N-ε-carboxyethyllysine, were monitored. Roasting induced the formation of 5-hydroxymethylfurfural, acrylamide, and dicarbonyl compounds, except furan, significantly ( p < 0.05). 5-Hydroxymethylfurfural and acrylamide content of roasted sesame seeds were found to vary as 3-40 mg/kg and 135-633 µg/kg, respectively. Dicarbonyl compounds were in the following order: methylglyoxal > 3-deoxyglucosone > 1-deoxyglucosone > diacetyl. On the other hand, N-ε-fructosyllysine concentration decreased while the roasting temperature increased; however, N-ε-carboxymethyllysine and N-ε-carboxyethyllysine formation was induced under those conditions. This is the first study reporting the formation of thermal process contaminants and glycation markers in sesame seeds through Maillard reaction during roasting.


Assuntos
Produtos Finais de Glicação Avançada/química , Sementes/química , Sesamum/química , Acrilamida/química , Culinária , Furanos/química , Temperatura Alta , Reação de Maillard , Oxirredução
14.
Molecules ; 24(8)2019 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-31010039

RESUMO

Background: The impact of thermal treatment on acrylamide (ACR) and hydroxymethylfurfural (HMF) formation was investigated for thermally treated sea buckthorn purée. Methods: An optimized procedure for minimizing ACR and HMF formation in thermally treated sea buckthorn purée was described. The precursors of ACR and HMF and their impact in heating of sea buckthorn purée to obtain jam-like products were also evaluated. Results: The contaminant content formed in samples was analyzed on thirteen running variants using a temperature range of 59.3-200.7 °C, and for heating durations between 5.9 and 34.1 min. The calculated equations of contaminant formation in sea buckthorn purée have established that the minimum content is formed at the lowest exposure time, between 10 and 20 min, for both ACR and HMF. The lowest ACR content was attained at 5.9-min exposure time and 130 °C temperature (0.3 µg/kg). For HMF the results revealed a lower quantity at 59.3 °C for 20-min exposure time (1.4 mg/kg). Conclusions: the found model is useful for the prediction of the best temperature/time conditions of the thermal treatment to obtain the lowest contaminates levels in the final product.


Assuntos
Hippophae/química , Hippophae/metabolismo , Temperatura Ambiente , Acrilamida/química , Acrilamida/metabolismo , Antioxidantes/química , Antioxidantes/metabolismo , Furaldeído/análogos & derivados , Furaldeído/química , Furaldeído/metabolismo , Modelos Teóricos
15.
Bull Environ Contam Toxicol ; 102(4): 560-566, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30859246

RESUMO

A fast, green and low cost method for analysis of acrylamide in tap and well water has been presented for the first time using solvent terminated-dispersive liquid liquid microextraction (ST-DLLME) with a simple equipment which does not need centrifugation step followed by GC-FID. The use of one variable at a time optimization method revealed that methanol and octanone were the superior disperser and extraction solvents, respectively. A central composite design (CCD) as a response surface methodology was used for multivariate optimization of five independent factors (volumes of extraction and dispersive solvents, pH, salt addition and extraction time) on the extraction efficiency. Under CCD optimal conditions, the linear range, detection limit (S/N = 3) and quantitation limit (S/N = 10) were 0.1, 0.3 and 0.3-550 ng mL-1, respectively. In these circumstances, the recoveries for real samples (tap and well water) spiked with 0.5, 1 and 10 ng g-1 were in the acceptable range (90.8%-94.1%). In comparison with other methods in the literature, the suggested ST-DLLME approach showed the best analytical performance. The presented green method has potential application as a routine method in the environmental and analytical laboratories for analysis of acrylamide in water samples.


Assuntos
Acrilamida/química , Cromatografia Gasosa/métodos , Água Potável/química , Microextração em Fase Líquida/métodos , Poluentes Químicos da Água/química , Limite de Detecção , Metanol , Solventes
16.
Methods Mol Biol ; 1922: 251-265, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30838583

RESUMO

In this chapter we discuss the potential of preparative SDS-PAGE for use in purifying native developing enamel matrix proteins. We believe that the methodology has the potential to provide the relatively large-scale single-step purification of any enamel protein that can be resolved as a single band during analytical SDS-PAGE. Of course, a single band on analytical SDS-PAGE does not guarantee absolute purity as the band may be comprised of two or more proteins migrating at the same apparent molecular weight on the gel. Where absolute purity is required, the methodology can be used in conjunction with other techniques such as ion-exchange chromatography or reverse-phase chromatography. We do not see preparative SDS-PAGE replacing chromatographic methodologies but believe that it can provide another powerful tool to add to the battery of purification techniques already available to researchers in the field.


Assuntos
Amelogenina/isolamento & purificação , Proteínas do Esmalte Dentário/isolamento & purificação , Eletroforese em Gel de Poliacrilamida/métodos , Acrilamida/química , Animais , Eletroforese em Gel de Poliacrilamida/instrumentação , Desenho de Equipamento , Géis/química , Porosidade , Suínos
17.
J Chromatogr A ; 1597: 187-195, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-30922722

RESUMO

Ion exchangers of high binding capacity and uptake rate are desired for high performance purification of proteins by ion exchange chromatography. For this purpose, we have herein developed a new anion exchanger by grafting N,N-Dimethylaminopropyl acrylamide (DMAPAA) onto Sepharose FF by atom transfer radical polymerization. Six DMAPAA-grafted Sepharose FF resins of the same grafting density but different chain lengths (ionic capacities, ICs) were prepared, and named as FF-pDMAPAAn (n denotes IC value, 65-831 mmol/L). Bovine serum albumin (BSA) adsorption and its chromatography were studied to evaluate the anion exchange resins. It was found that the equilibrium protein adsorption capacity (qm) increased rapidly from 91 mg/mL at IC = 65 mmol/L till reaching a peak value (368 mg/mL) at IC = 458 mmol/L and then decreased slightly with further increasing IC (chain length) to 831 mmol/L. The uptake rate, De/D0, defined as the ratio of effective diffusion coefficient (De) to free diffusivity of the protein (D0), also presented similar changes as a function of IC. Namely, De/D0 increased from 0.25 to 2.45 in the IC range of 65 to 458 mmol/L, kept almost unchanged from 458 to 573 mmol/L and then decreased slightly with further increase of IC to 831 mmol/L. Therefore, FF-pDMAPAA458 presented the best performance of the six resins for BSA adsorption, possessing very high qm and De/D0 values (368 mg/mL and 2.45, respectively). The resin was thus extensively characterized in the effect of ionic strength and column chromatography. The qm and De/D0 of FF-pDMAPAA458 were much higher than other anion exchangers reported in literatures and kept over 230 mg/mL and 2.3, respectively, at salt concentrations up to 100 mmol/L. Therefore, the dynamic binding capacity of the FF-pDMAPAA458 column was remarkably higher than Q Sepharose FF and other two typical polymer-grafted anion exchangers reported in literatures in the salt concentration range, and kept as high as 180-220 mg/mL in the superficial flow velocity rang of 150-1350 cm/h. Taken together, the results demonstrated that FF-pDMAPAA resins of appropriate ionic capacities are promising for high-performance protein chromatography.


Assuntos
Resinas de Troca de Ânions/química , Cromatografia por Troca Iônica/métodos , Proteínas/química , Sefarose/química , Acrilamida/química , Adsorção , Cromatografia por Troca Iônica/instrumentação , Íons/química , Cinética , Concentração Osmolar , Polietilenoimina/química , Soroalbumina Bovina/química
18.
Anal Chim Acta ; 1058: 107-116, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-30851844

RESUMO

Increasing researches proved that abnormal glycosylation is strongly correlated with many diseases. Specially, site-specific glycosylation and its associated heterogeneity are closely related to the function and activity of the glycoprotein. However, intact N-glycopeptide analysis still faces great challenges because the presence of highly abundant non-glycosylated peptides would suppress the ionization of lowly abundant glycopeptides. In the present study, we developed a practical intact tryptic N-glycopeptide enrichment method using acrylamide-agarose composite gel that combined the size exclusion chromatography and hydrophilic (named SELIC) effects, aimed to remove the detergent rapidly and effectively, as well as enrich intact N-glycopeptides while extracting peptides. This is a useful tool to facilitate the intact N-glycopeptides analysis of complex protein mixtures, particularly for samples that extracted from formalin-fixed and paraffin-embedded (FFPE) tissues by SDS. Using this method, we successfully identified 700 site-specific intact tryptic N-glycopeptides corresponding to 261 glycosylation sites on 191 glycoproteins from FFPE thymoma tissues.


Assuntos
Acrilamida/química , Cromatografia em Gel/métodos , Glicopeptídeos/análise , Sefarose/química , Timoma/química , Neoplasias do Timo/química , Animais , Glicopeptídeos/química , Glicoproteínas/química , Glicosilação , Humanos , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Proteólise , Tripsina/química
19.
Food Chem ; 283: 422-430, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30722893

RESUMO

The endocrine system is highly sensitive to endocrine-disrupting chemicals (EDC) which interfere with metabolism, growth and reproduction throughout different periods of life, especially in the embryonic and pubertal stages, in which gene reprogramming may be associated with impaired development and control of tissues/organs even in adulthood. Acrylamide is considered a potential EDC and its main source comes from fried, baked and roasted foods that are widely consumed by children, teenagers and adults around the world. This review aimed to present some aspects regarding the acrylamide formation, its toxicokinetics, the occurrence of acrylamide in foods, the recent findings about its effects on different systems and the consequences for the human healthy. The challenges to characterize the molecular mechanisms triggered by acrylamide and to establish safe levels of consumption and/or exposure are also discussed in the present review.


Assuntos
Acrilamida/toxicidade , Disruptores Endócrinos/toxicidade , Sistema Nervoso/efeitos dos fármacos , Acrilamida/química , Acrilamida/farmacocinética , Animais , Criança , Disruptores Endócrinos/química , Disruptores Endócrinos/farmacocinética , Humanos , Sistema Nervoso/crescimento & desenvolvimento , Sistema Nervoso/metabolismo , Hipófise/efeitos dos fármacos , Hipófise/metabolismo , Reprodução/efeitos dos fármacos , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/metabolismo
20.
Food Chem ; 284: 236-244, 2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-30744852

RESUMO

In light of a recent update in EU regulations governing levels of acrylamide in foodstuffs, further understanding of the role of different precursors is fundamental to extending mitigation strategies into a wider product range. Kinetic modelling was used to investigate the role of maltose in the formation of acrylamide during the finish-frying of french fries. The maltose concentration of raw white potato strips was systematically increased from 0 to 1.4% to observe the effect of this reducing disaccharide on acrylamide formation. A mathematical model, incorporating glucose, fructose and maltose and based on known Maillard reaction pathways, was developed which showed that acrylamide formation from maltose only contributed <10% to the total acrylamide. An additional kinetic model allowed for the formation of acrylamide directly from sugar-asparagine glycoconjugates. This model suggested that under these conditions, it is unlikely that acrylamide is formed directly from the maltose-asparagine conjugate.


Assuntos
Acrilamida/química , Culinária/métodos , Maltose/química , Solanum tuberosum/química , Acrilamida/análise , Asparagina , Frutose/química , Glucose/química , Cinética , Reação de Maillard , Modelos Químicos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA