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1.
Anal Chem ; 93(3): 1352-1359, 2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33347273

RESUMO

Proteins are perhaps the most important yet frustratingly complicated and difficult class of compounds to analyze, manipulate, and use. One very attractive option to characterize and differentially concentrate proteins is dielectrophoresis, but according to accepted theory, the force on smaller particles the size of proteins is too low to overcome diffusive action. Here, three model proteins, immunoglobulin G, α-chymotrypsinogen A, and lysozyme, are shown to generate forces much larger than predicted by established theory are more consistent with new theoretical constructs, which include the dipole moment and interfacial polarizability. The forces exerted on the proteins are quantitatively measured against well-established electrophoretic and diffusive processes and differ for each. These forces are orders of magnitude larger than previously predicted and enable the selective isolation and concentration of proteins consistent with an extremely high-resolution separation and concentration system based on the higher-order electric properties. The separations occur over a small footprint, happen quickly, and can be made in series or parallel (and in any order) on simple devices.


Assuntos
Quimotripsinogênio/análise , Imunoglobulina G/análise , Muramidase/análise , Animais , Galinhas , Clara de Ovo/análise , Eletroforese , Muramidase/metabolismo
2.
Food Chem ; 345: 128822, 2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-33352406

RESUMO

The presence of residues from fining agents in wines may represent a risk for allergic consumers and a source of discomfort for others, such as vegans. Even though ELISA is the official detection method for such residues, this technique may be hindered by cross-reactivity issues, or by matrix-molecule interference due to a high polyphenol content, especially in red wines. An HRMS-based method has been developed to detect pig gelatin and egg white in experimental five-year aged Nebbiolo-based red wine. Biomarker peptides were selected, after tryptic digestion, and quantified by multitarget nanoHPLC-HRMS analysis. The method resulted in an LLOQs of 5 µg/mL in the experimental wine, and between 1 and 2 µg/mL in the buffer. This method allowed both gelatin and egg white proteins to be detected and quantified in aged red wine, while whereas the commercial ELISA kit was instead unable to detect egg white in the same samples.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Clara de Ovo/análise , Análise de Alimentos/métodos , Gelatina/análise , Espectrometria de Massas/métodos , Nanotecnologia/métodos , Vinho/análise , Animais , Suínos
3.
Poult Sci ; 99(3): 1705-1716, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32115038

RESUMO

Vanadium (V) is an ultratrace metal with the insulin-tropic properties and is often researched as the diabetes drug. However, in animals, V has been reported to have toxic effects on the development, immunity, oxidation-reduction equilibrium, gastrointestinal function, and so forth. Especially in poultry, supplementation of more than 10 mg of V/kg in the layer diets has been shown to adversely affect the egg production and egg quality. In this study, we supplemented 0 mg of V/kg, 5 mg of V/kg, and 10 mg of V/kg in the layer diets for 35 D and examined the quantitative proteomics of albumen for finding the possible target signaling pathway and mechanism of V action and made the preliminary verification. In contrast to the control group, V resulted in a significant drop in the albumen height, and in oviduct ampulla, the activity of total antioxidant capacity and glutathione peroxidase significantly decreased (P = 0.01, P = 0.02), the content of malonic dialdehyde significantly increased (P = 0.01), and the apoptosis rate significantly increased in the 5-mg V/kg and 10-mg V/kg treatment groups (P < 0.01). V affected 36 differentially accumulated proteins in albumen, with 23 proteins upregulated and 13 proteins downregulated. The expressions of innate protein albumen lysozyme (Q6LEL2), vitellogenin-2 (P02845), and the F1NWD0 protein in albumen belonged to the P53 family were significantly reduced, in contrast to the control (P < 0.05), and the expression of riboflavin-binding protein (P02752) was significantly improved (P < 0.05). The Hippo signaling pathway-fly, which is suitable for the key protein P53 as the most significantly affected network, might be important for discriminating V.


Assuntos
Ração Animal/análise , Clara de Ovo/análise , Proteoma , Vanádio/efeitos adversos , Animais , Galinhas , Dieta/veterinária , Proteínas do Ovo/química , Feminino , Oviductos , Transdução de Sinais
4.
Anim Sci J ; 91(1): e13339, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32219937

RESUMO

In this study, the effects of ultrafiltration technique on the desalination efficiency, nutrient content, physicochemical properties, functional properties, texture profile, and microstructure of salted duck egg white were evaluated. The results showed that ultrafiltration can remove 92.93% salt from salted duck egg white (SDEW) and final salt% of desalted duck egg white (DDEW) was 0.65%. The analysis of nutrient content and amino acid of SDEW and desalted duck egg white powder (DDEWP) sample was significantly lower than those of fresh duck egg white (FDEW). Although emulsifying capacity of SDEW, DDEW, and DDEWP exhibited significantly lower than that of FDEW, an excellent foaming ability was found in those samples. Moreover, the texture profiles (gel strength, hardness and elasticity) of SDEW, DDEW, and DDEWP samples presented lower value than FDEW. The observation of microstructure, DDEWP possessed smooth surface of protein globules with deep hole liked donuts and distribution of a few of salt crystals. While salted duck egg white powder (SDEWP) had a raisin-like surface formation with salt formed cubic crystals. Overall, both liquid and dried material of desalted duck egg could be used as a good ingredient in baking food due to their excellent foaming capacity.


Assuntos
Patos , Clara de Ovo/análise , Análise de Alimentos/métodos , Nutrientes/análise , Ultrafiltração/métodos , Animais , Fenômenos Químicos , Clara de Ovo/química
5.
BMC Plant Biol ; 20(1): 126, 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32209052

RESUMO

BACKGROUND: A microgranule fertilizer was designed for localized fertilization of soil with controlled release of nutrients. The microgranule matrix was fortified with proteins, which were obtained from food industry byproducts or waste, i.e., whey protein from milk serum, soy protein from soy isolate and egg white protein from chicken egg white powder. The mechanism of the protein decomposition and migration of micro and macromolecule compounds through two different model soil systems was investigated. The potential of the protein fortified fertilizer for localized fertilization of the potted maize seeds was evaluated. RESULTS: The study revealed that proteins slowly diffused through soil with simultaneous degradation, which was accompanied with release of ammonia ions. The highest concentration of proteins and degradation products was found in a close vicinity of the microgranule. The microgranules were used as a local fertilizer for maize seeds in the pot experiments. The experiments confirmed statistically significant improvement in root density of maize plant compared to control group. CONCLUSIONS: Byproducts or waste of food industry, such as the milk serum and soy can be used as a source of proteins that degrade in soil without a pretreatment. The degradation is accompanied with formation of ammonium ions, which can be utilized by plants as a nitrogen source. The fertilizer microgranule should be placed in a close vicinity to the plant seed, since the maximum of the protein concentration and ammonia ions is reached at a very close distance from the microgranule.


Assuntos
Fertilizantes/análise , Indústria Alimentícia , Resíduos Industriais/análise , Nutrientes/metabolismo , Zea mays/fisiologia , Animais , Clara de Ovo/análise , Leite/química , Pós/análise , Soja/química
6.
Food Chem ; 317: 126430, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32092612

RESUMO

Electrochemical Synchronous detection of cadmium (Cd(II)) and lead (Pb(II)) was obtained by acid treated multiwalled carbon nanotube (A-MWCNT) functionalized with hyaluronic acid (Hyalu) and this mixture was separately further modified with l-cysteine (l-Cys) and l-serine (l-Ser). Under the optimized circumstance best voltammetric responses were produced by A-MWCNT/Hyalu/l-Cys and A-MWCNT/Hyalu/l-Ser modified electrodes. The peak current was linearly dependent on the Cd(II) and Pb(II) concentrations in the range from 0.4 to 4 µg L-1. The sensitivities were calculated as 0.7 µA/nM (Cd(II)) and 3.5 µA/nM (Pb(II)) for A-MWCNT/Hyalu/l-Cys/GCE and 0.6 µA/nM (Cd(II)) and 2.6 µA/nM (Pb(II)) for A-MWCNT/Hyalu/l-Ser/GCE. From the calibration plot LODs were calculated to be 0.032 µg L-1 (Cd(II)) and 0.015 µg L-1 (Pb(II)) for A-MWCNT/Hyalu/l-Cys/GCE and 0.057 µg L-1 (Cd(II)) and 0.034 µg L-1 (Pb(II)) for A-MWCNT/Hyalu/l-Ser/GCE. Moreover, the proposed electrodes were subjected to the real sample application in honey, cocos nucifera and egg white.


Assuntos
Cádmio/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Chumbo/análise , Nanocompostos/química , Cádmio/química , Calibragem , Cocos/química , Cisteína/química , Clara de Ovo/análise , Eletrodos , Análise de Alimentos/instrumentação , Mel/análise , Ácido Hialurônico/química , Chumbo/química , Limite de Detecção , Nanotubos de Carbono/química , Sensibilidade e Especificidade , Serina/química
7.
Food Chem ; 315: 126207, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31991252

RESUMO

Five major proteins from egg white were separated using a successive extraction/precipitation protocol. The yield and purity of the separated proteins were measured. The separated proteins were confirmed by MALDI-TOF-MS, and their structures were characterized by CD spectrum. Lysozyme was first separated using FPC 3500 resin and then ovomucin from the lysozyme-free egg white. Ammonium sulfate and citric acid were added to the resulting lysozyme- and ovomucin-free egg white solution to precipitate ovotransferrin. Ovomucoid and ovalbumin were separated from the resulting supernatant using ethanol. The separated proteins were further purified and the optimal conditions for the further purifications were suggested. The purity and yield of lysozyme, ovotransferrin, ovalbumin, and ovomucoid were higher than 90% and 77%, while those of ovomucin were about 72% and 75%, respectively. This study separated five major proteins in egg white successively using resin adsorption, pH adjustment, salt/ethanol precipitation, and ultrafiltration.


Assuntos
Fracionamento Químico/métodos , Proteínas do Ovo/análise , Proteínas do Ovo/isolamento & purificação , Clara de Ovo/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Sulfato de Amônio/química , Animais , Precipitação Química , Conalbumina/análise , Conalbumina/isolamento & purificação , Proteínas do Ovo/química , Clara de Ovo/análise , Etanol/química , Muramidase/análise , Muramidase/isolamento & purificação , Ovalbumina/análise , Ovalbumina/isolamento & purificação , Ovomucina/análise , Ovomucina/isolamento & purificação , Estrutura Secundária de Proteína
8.
Luminescence ; 34(3): 316-323, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30724008

RESUMO

A novel, rapid and sensitive chemiluminescence (CL) method for the determination of oxytetracycline hydrochloride (OTCH) is described in this paper. The presented method was based on the fact that OTCH could immensely enhance the CL of the reaction of cerium sulfate and tris(2,2-bipyridyl) ruthenium (II) in acidic medium. Under optimal experimental conditions, CL intensity was favorably linear for OTCH in the range 5.0 × 10-7 to 5.0 × 10-5  g/ml, with a detection limit of 1.5 × 10-7  g/ml (S/N = 3). The relative standard detection was 4.76% for 5.0 × 10-6  g/ml (n = 11). This method was successfully applied to the analysis of OTCH in milk and egg white samples. According to the results of the kinetic curves for OTCH in the Ru(bipy)3 2+ -Ce(SO4 )2 CL system, together with CL and ultraviolet (UV)-visible spectra, the possible mechanism of the CL reaction is discussed briefly.


Assuntos
Antibacterianos/análise , Clara de Ovo/análise , Medições Luminescentes/métodos , Leite/química , Oxitetraciclina/análise , Animais , Bovinos , Cério/química , Galinhas , Contaminação de Alimentos/análise , Medições Luminescentes/instrumentação , Rutênio/química , Sulfatos/química
9.
J Sci Food Agric ; 99(8): 3879-3885, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30680735

RESUMO

BACKGROUND: Egg yolks contain large amounts of cholesterol and are suspected to be harmful after long-term consumption. In this experiment, 63 rats were used to evaluate the effect of egg white (EW) and egg yolk (EY) supplementation on serum lipids and brain cognition. The feeding time lasted 4 weeks after a 1-week acclimation. RESULTS: Body weight was significantly higher in rats fed 132.0 g kg-1 EW and significantly lower when fed 40 g kg-1 EY (P < 0.05). Total cholesterol and low-density lipoprotein increased in rats fed 72.0 g kg-1 EW compared with rats from NC and EY groups (P < 0.05). High-density lipoprotein (HDL) was higher in rats fed 40 g kg-1 EY and decreased when fed 72.0 g kg-1 EW (P < 0.05). Rats fed a diet with EY exhibited abundant neurons in the CA1 hippocampus and complete subcellular structures. Rats fed 132 g kg-1 EW exhibited shrunken cells and swollen mitochondria. Brain-derived neurotrophic factor had constitutively low expression among groups, while tyrosine kinase B (TrkB) exhibited higher expression levels in rats fed a diet containing EY compared with other groups (P < 0.05). CONCLUSION: EY consumption reduced body weight and increased HDL levels. Diet containing EY could improve cognition through enhanced trkB expression. © 2019 Society of Chemical Industry.


Assuntos
Peso Corporal , Encéfalo/enzimologia , Gema de Ovo/metabolismo , Lipoproteínas HDL/sangue , Receptor trkB/metabolismo , Animais , Encéfalo/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Contagem de Células , Colesterol/sangue , Dieta , Clara de Ovo/análise , Hipocampo/metabolismo , Masculino , Neurônios/citologia , Neurônios/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor trkB/genética
10.
Poult Sci ; 98(1): 473-479, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30107537

RESUMO

Ovomucin is known to be critical for keeping the high quality and freshness of thick albumen, but there is lack of understanding on the dynamics changes of this important protein during storage. This study aimed to investigate the relationship between ovomucin content and egg freshness during storage. Firstly, the viscoelasticity of albumen was shown to be much higher than that of ovomucin-depleted albumen from rheological analysis results, indicating that ovomucin is an important component in maintaining the natural viscoelasticity of albumen. Then, the ovomucin content determined by ELISA method was compared to albumen pH, Haugh unit (HU), and yolk index in terms of egg white quality and to the time of storage in terms of egg freshness at 4°C, 25°C, and 37°C, respectively. Results of the transformation kinetic showed a decrease in ovomucin content with prolonged storage time (P ≤ 0.01). Correlation analysis showed a high positive correlation between ovomucin content and HU (P ≤ 0.01) and a high negative correlation between ovomucin content and the albumen pH (P ≤ 0.01) at the test temperatures. We therefore conclude that ovomucin content in albumen can be used as an index for egg freshness. At last, predictive models of the equivalent egg age (4°C and 25°C) for evaluating the egg freshness were established by means of exponential regression model with ovomucin content as the variable. These results can provide a theoretical and technical basis for the storage and fresh evaluation of shell eggs.


Assuntos
Clara de Ovo/análise , Ovos/normas , Armazenamento de Alimentos , Ovomucina/análise , Animais , Galinhas , Gema de Ovo , Ovos/análise , Concentração de Íons de Hidrogênio , Temperatura , Fatores de Tempo , Viscosidade
11.
J Agric Food Chem ; 66(48): 12805-12814, 2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30415537

RESUMO

The dose-dependent effect of egg consumption on plasma cholesterol in humans remains inconclusive. It is unknown if egg white consumed in a normal amount can reduce plasma cholesterol. We used hamsters as a model to (i) investigate the dose-dependent effect of consuming zero to five whole eggs on plasma total cholesterol (TC) and (ii) examine if egg white, equivalent to one to five eggs, possessed any reducing effects on plasma TC. In experiment 1, hamsters were divided into six groups ( n = 8 each) and fed either a control diet or one of five experimental diets supplemented with whole-egg powder equivalent to one to five eggs per 2000 kcal. Results showed that supplementation with one egg increased plasma TC by 25% compared with that of the control (226 ± 16 versus 282 ± 56 mg/dL, p < 0.05), whereas supplementation with two to five eggs did not significantly produce any additional effects on plasma cholesterol. However, supplementation with one to five eggs in diets caused a dose-dependent accumulation of cholesterol in the liver from 21.5 ± 4.4 to 71.3 ± 7.3 mg/g ( p < 0.01). In the second experiment, hamsters were divided into six groups and fed either a high-cholesterol control diet or one of five experimental diets supplemented with egg-white powder from one to five eggs. Results showed that egg-white powder affected neither plasma nor liver cholesterol levels. The egg-white powder did not affect fecal sterol excretion, suggesting it had no effect on cholesterol absorption. It was therefore concluded that consumption of two to five eggs did not significantly produce any additional effects on plasma cholesterol, whereas egg white did not possess a plasma-cholesterol-lowering activity if it was consumed at amounts similar to those in a normal human diet.


Assuntos
Colesterol/metabolismo , Clara de Ovo/análise , Ovos/análise , Fígado/metabolismo , Plasma/metabolismo , Animais , Galinhas , Colesterol/sangue , Cricetinae , Dieta , Masculino , Mesocricetus
12.
J Biomed Opt ; 21(12): 125004, 2016 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-27942719

RESUMO

We performed the feasibility study using speckle variance optical coherence tomography (SvOCT) to monitor the thermally induced protein denaturation and coagulation process as a function of temperature and depth. SvOCT provided the depth-resolved image of protein denaturation and coagulation with microscale resolution. This study was conducted using egg white. During the heating process, as the temperature increased, increases in the speckle variance signal was observed as the egg white proteins coagulated. Additionally, by calculating the cross-correlation coefficient in specific areas, denaturized egg white conditions were successfully estimated. These results indicate that SvOCT could be used to monitor the denaturation process of various proteins.


Assuntos
Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Desnaturação Proteica , Tomografia de Coerência Óptica , Animais , Clara de Ovo/análise , Estudos de Viabilidade , Agregados Proteicos
13.
Biochem Biophys Res Commun ; 475(1): 107-12, 2016 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-27178210

RESUMO

Ovalbumin (OA) is the most abundant ingredient of chicken egg-white allergenic proteins. In the present study we investigated the possibility of reducing OA allergenicity by treatment with a natural protein exhibiting N-acetylglucosaminidase (NA) activity. Ascidian is cultivated as a food resource in northeast Asia. The ascidian viscera NA (AVNA) with almost no other exoglycosidases or proteolytic enzymes was isolated by applying size-exclusion chromatography to a protein precipitate of ascidian viscera. Intact OA was mixed with AVNA containing 0.2, 1.0, and 5.0 Units of NA. Anion-exchange chromatography was then used to isolate OA from AVNA-treated OA. The electrophoretic patterns and N-glycans of each isolated OA from AVNA-treated OA (iOA) were analyzed, and the terminal N-acetylglucosamines of iOA were selectively cleaved with no other degradation occurring. A competitive indirect enzyme-linked immunosorbent assay using rabbit anti-OA sera was performed to investigate the allergenicity of iOA, which was found to be significantly reduced depending on the increased NA activity compared to that of intact OA. These results indicate that OA allergenicity was reduced using a simple and mild treatment process with AVNA, and suggest that ascidian NA is an efficient natural protein for reducing the allergenicity of OA without requiring the use of harsh physical treatments or chemical conjugation.


Assuntos
Acetilglucosaminidase/metabolismo , Alérgenos/metabolismo , Ovalbumina/metabolismo , Urocordados/enzimologia , Acetilglucosaminidase/isolamento & purificação , Alérgenos/imunologia , Animais , Galinhas , Clara de Ovo/análise , Hipersensibilidade Alimentar/imunologia , Hipersensibilidade Alimentar/metabolismo , Hipersensibilidade Alimentar/prevenção & controle , Ovalbumina/imunologia , Coelhos , Vísceras/enzimologia
14.
Poult Sci ; 95(7): 1702-1708, 2016 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-27118861

RESUMO

Purified egg white is an important ingredient in a number of baked and confectionary foods because of its foaming properties. However, yolk contamination in amounts as low as 0.01% can impede the foaming ability of egg white. In this study, we used Raman spectroscopy to evaluate the hypothesis that yolk contamination in egg white could be detected based on its molecular optical properties. Yolk contaminated egg white samples (n = 115) with contamination levels ranging from 0% to 0.25% (on weight basis) were prepared. The samples were excited with a 785 nm laser and Raman spectra from 250 to 3,200 cm(-1) were recorded. The Raman spectra were baseline corrected using an optimized piecewise cubic interpolation on each spectrum and then normalized with a standard normal variate transformation. Samples were randomly divided into calibration (n = 77) and validation (n = 38) data sets. A partial least squares regression (PLSR) model was developed to predict yolk contamination levels, based on the Raman spectral fingerprint. Raman spectral peaks, in the spectral region of 1,080 and 1,666 cm(-1), had the largest influence on detecting yolk contamination in egg white. The PLSR model was able to correctly predict yolk contamination levels with an R(2) = 0.90 in the validation data set. These results demonstrate the capability of Raman spectroscopy for detection of yolk contamination at very low levels in egg white and present a strong case for development of an on-line system to be deployed in egg processing plants.


Assuntos
Galinhas , Clara de Ovo/análise , Gema de Ovo/química , Manipulação de Alimentos , Animais , Análise dos Mínimos Quadrados , Análise Espectral Raman
15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(4): 919-23, 2015 Apr.
Artigo em Japonês | MEDLINE | ID: mdl-26197575

RESUMO

Due to the harmfulness of melamine to human, the quantitative detection of melamine in egg is very necessary. In the present study, the surface enhanced Raman spectra technology combined with chemometric analysis method was used to conduct melamine quantitative detection in egg white. Firstly, the melamine egg sample could be got by the method of artificial feeding hens usingdifferent feeding formulation. Then the surface enhanced Raman spectra of egg white was determined using portable Raman spectroscopy (Opto Trace RamTracer-200) and Raman enhancement reagents, and the melamine content within the white eggs was measured with gas chromatography mass spectrometry technology. The software of Raman Analyzer was used for baseline correction of Raman spectra. The correlation coefficient method was used to choose 320 spectral variables from the surface enhanced Raman spectroscopy as input variables to establish partial least squares quantitative calibration model . And the peaks-decomposition method was used to establish peaks-decomposition quantitative calibration model. Both models selected 90 and 44 samples respectively as calibration sets and validation sets during model establishment, and both models achieved good prediction effect. The determination coefficient between predicted values of partial least squares quantitative calibration model and measured values of gas chromatography mass spectrometry was 0.856, and root mean square error of prediction was 1.547. The determination coefficient was 0.947 and RMSEP was 0.893 for the peaks-decomposition quantitative calibration model. This study demonstrated that the method can effectively quantitatively detect melamine in eggs. Testing a sample only takes 15 minutes, which can provide a new way for the melamine egg detection.


Assuntos
Clara de Ovo/análise , Contaminação de Alimentos/análise , Análise Espectral Raman , Triazinas/análise , Cromatografia Gasosa-Espectrometria de Massas , Análise dos Mínimos Quadrados , Modelos Teóricos
16.
Biosens Bioelectron ; 74: 270-6, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26143467

RESUMO

In this study, we reported iminodiacetic acid-copper ion complex (IDA-Cu) immobilized onto gold nanoparticles (GNPs)-modified glassy carbon electrode as a novel electrochemical platform for selective and sensitive determination of lysozyme (Lys). IDA-Cu complex acted as an efficient recognition element capable of capturing Lys molecules. GNPs acts as a substrate to immobilize IDA-Cu coordinative complex and its interaction with Lys leds to a great signal amplification through measuring changes in differential pulse voltammetric (DPV) peak current of [Fe(CN)6](3-/4-) redox probe. Upon the recognition of the Lys to the IDA-Cu, the peak current decreased due to the hindered electron transfer reaction on the electrode surface. Under optimum condition, it was found that the proposed method could detect Lys at wide linear concentration range (0.1 pM to 0.10 mM) with detection limit of 60 fM. Furthermore, electrochemical impedance spectroscopy (EIS) detection of Lys was demonstrated as a simple and rapid alternative analytical technique with detection limit of 80 fM at concentration range up to 0.1mM. In addition, the proposed sensor was satisfactorily applied to the determination of Lys in real samples such as hen egg white. The proposed modified electrode showing the high selectivity, good sensitivity and stability toward Lys detection may hold a great promise in developing other electrochemical sensors based on metal-chelate affinity complexes.


Assuntos
Cobre/química , Clara de Ovo/análise , Ouro/química , Iminoácidos/química , Nanopartículas Metálicas/química , Muramidase/análise , Animais , Técnicas Biossensoriais/instrumentação , Quelantes/química , Galinhas , Técnicas Eletroquímicas/instrumentação , Eletrodos , Desenho de Equipamento , Limite de Detecção , Modelos Moleculares
17.
Anal Chim Acta ; 857: 71-8, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25604822

RESUMO

In this study, a peptide-1 (RNRCKGTDVQAW) constructing lysozyme was conjugated with an electroactive daunomycin in order to voltammetrically detect ovalbumin (OVA). Hetero-bifunctional cross-linking agents with four kinds of ethylene chains in differing lengths were used to bind the peptide-1 and daunomycin. After a cross-linking agent had reacted with an amino group of daunomycin, the compound was introduced into the peptide to the cysteine residue in the peptide using a pendant arm. The OVA was sensed via a change in the electrode response of the daunomycin moiety, based on the binding between the peptide and the OVA. The adsorption of the peptide probe on the electrode increased with increases in the ethylene chain. The binding constants between the peptide probes and the OVA, however, did not depend on the length of the chain. This was because the ethylene chain influenced the binding. When the peptide and the daunomycin were bound using N-(6-maleimidocaproyloxy) sulfosuccinimide, the electrode response of the peptide probe was the most sensitive from among the four cross-linking agents. The calibration curve of the OVA using the peptide probe was linear and ranged from 1.5×10(-11) to 3.0×10(-10)M. Furthermore, this method could be applied to the electrochemical sensing of the OVA in egg whites and in fetal bovine serum.


Assuntos
Daunorrubicina/química , Técnicas Eletroquímicas/métodos , Técnicas de Sonda Molecular , Ovalbumina/análise , Peptídeos/química , Animais , Bovinos , Embrião de Galinha , Galinhas , Reagentes para Ligações Cruzadas/química , Clara de Ovo/análise , Clara de Ovo/química , Eletrodos , Espectrometria de Massas , Sondas Moleculares/química , Muramidase/química , Ovalbumina/metabolismo , Peptídeos/metabolismo , Codorniz , Sensibilidade e Especificidade , Soro/química
18.
Food Chem ; 168: 580-7, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25172751

RESUMO

To alleviate the risk to allergic consumers, it is crucial to improve factors affecting the detection of food allergens in processed chocolate products. This study evaluated processing effects on (1) recovery of peanut, egg, and milk allergens using five different extraction buffers, and (2) identification of specific allergenic proteins from extracts of incurred chocolate using allergen-specific antibodies and human allergic sera. Immunochemical staining with polyclonal antibodies showed that the addition of detergent or reducing agent improved extraction efficiency of peanut proteins, but not of egg and milk proteins. Tempering decreased antibody binding regardless of extractant. Detection of IgE-reactive peanut, egg, and milk allergens was differentially affected by tempering and extractant. Detection problems associated with matrix and processing effects may be overcome by the choice of extraction buffer and detecting antibody.


Assuntos
Alérgenos/análise , Alérgenos/isolamento & purificação , Arachis/metabolismo , Cacau/metabolismo , Alérgenos/imunologia , Animais , Anticorpos/imunologia , Western Blotting , Galinhas , Clara de Ovo/análise , Humanos , Imunoglobulina E/imunologia , Leite/metabolismo , Proteínas do Leite/análise , Proteínas do Leite/imunologia
19.
J Sci Food Agric ; 95(5): 1080-7, 2015 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-24961676

RESUMO

BACKGROUND: Strontium is currently prescribed for patients with osteoporosis to increase bone density and reduce bone fractures but its relevance in animal nutrition is obscure. In order to investigate the effect of supplemental strontium and vitamin D3 on performance, egg quality and skeletal integrity in poultry a total of 108 laying hens, 99 weeks of age, were fed three levels of strontium (0, 500, 1000 mg kg(-1) ) and two levels of vitamin D3 (2500, 5,000 iu kg(-1)) over a 12-week period. RESULTS: There was an improvement (P < 0.05) in egg production and feed conversion efficiency with strontium at 500 mg kg(-1) and a significant increase in egg weight in those hens fed additional vitamin D3 . Supplemental strontium increased phosphorus, sodium and strontium retention in birds fed 2500 iu D3 kg(-1) but reduced phosphorus, sodium and strontium retention in birds fed 5000 iu D3 kg(-1), resulting in an interaction (P < 0.01) between strontium and vitamin D3 . Addition of 5000 iu D3 kg(-1) increased egg weight (P < 0.05); predominantly by increased albumen content (P < 0.05), whereas strontium supplementation reduced egg weight (P < 0.001). Similarly, 5000 iu kg(-1) D3 increased apparent metabolizable energy (P < 0.05); in contrast, strontium supplementation reduced (P < 0.05) apparent metabolizable energy. CONCLUSION: The addition of 500 mg kg(-1) strontium significantly improved egg production and feed efficiency; however, further investigation needs to be undertaken to refine the optimum level of strontium required to maximize hen performance. The interrelationship between strontium and vitamin D3 requires further exploratory study.


Assuntos
Galinhas/crescimento & desenvolvimento , Colecalciferol/administração & dosagem , Dieta/veterinária , Ovos , Qualidade dos Alimentos , Minerais/metabolismo , Estrôncio/administração & dosagem , Animais , Animais Endogâmicos , Densidade Óssea , Desenvolvimento Ósseo , Osso e Ossos/química , Osso e Ossos/metabolismo , Colecalciferol/efeitos adversos , Dieta/efeitos adversos , Casca de Ovo/química , Casca de Ovo/crescimento & desenvolvimento , Casca de Ovo/metabolismo , Clara de Ovo/análise , Gema de Ovo/química , Gema de Ovo/metabolismo , Ovos/análise , Ingestão de Energia , Metabolismo Energético , Feminino , Minerais/administração & dosagem , Minerais/análise , New South Wales , Ovalbumina/análise , Ovalbumina/metabolismo , Oviposição , Estrôncio/efeitos adversos , Tíbia
20.
Poult Sci ; 93(12): 3130-7, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25332139

RESUMO

In this paper, the physicochemical and nutritional characteristics of preserved duck egg white were analyzed and compared with fresh egg and hard-cooked egg white (n = 3). The data obtained showed that the preserved egg white was rich in essential amino acids and minerals, such as Ca, Mg, Fe, Zn, Cu, K, and Na. After fresh duck eggs were processed into preserved eggs, contents of moisture, CP, amino acid, and water-soluble vitamin of egg white significantly decreased (P < 0.05); however, pH, free amino acid content, and most inorganic elemental contents of egg white significantly increased (P < 0.05). The preserved egg white had higher a* (redness/greenness) and b* values (yellowness/blueness; P < 0.05) and lower L* value (lightness; P < 0.05) than hard-cooked egg white. The gel hardness of preserved egg white was approximately 50% of hard-cooked egg white; however, its springiness and cohesiveness were approximately 1.5 times of hard-cooked egg white. The results indicated that pickling with alkaline and other additives can significantly change physical properties and chemical composition of duck egg white, which make preserved egg white with characteristics of rich elements, brown color, and high springiness, but low vitamin.


Assuntos
Patos , Clara de Ovo/análise , Clara de Ovo/normas , Valor Nutritivo/fisiologia , Aminoácidos/química , Animais , Vitaminas/química
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