Red Wine Samples Research Articles

Building heterogeneous core–satellite chiral assemblies for ultrasensitive toxin detection

A chiral-aptasensor for ochratoxin A (OTA) detection based on Au core–Ag nanoparticle satellite assemblies was fabricated for the first time. High yields of Au core–Ag NP satellite assemblies were prepared in the aqueous phase and the optical properties of the Au core–Ag NP satellite assemblies were investigated in detail. Because of the different concentrations of the OTA target, the assembly degree of the architecture varied which led to the corresponding chiral signals. The developed method for OTA detection with excellent linear range from 1 to 50pg/mL showed high selectivity for OTA and the limit of detection as low as 0.16pg/mL. The feasibility of this method was demonstrated by performing recovery experiment using negative red wine samples, excellent recovery ranged from 90% to 105% was achieved, and indicated promising applications.

Determination of boron in Turkish wines by microwave plasma atomic emission spectrometry

Boron in various Turkish red wine and white wine samples was determined by microwave plasma-atomic emission spectrometry (MP-AES) at 249.677 nm. MP-AES is a novel instrument which provides a low-cost analysis based on a micro-wave plasma generated with nitrogen. Wine samples were not pre-treated prior to analysis. The recovery rate of boron added to the 1:1 diluted wine samples was around 80% which showed interference due to the matrix of the wine samples. Therefore standard addition method was used for quantifications. The limit of detection and limit of quantification were 0.08 and 0.28 μg mL−1, respectively. A satisfactory linearity (r2 > 0.999) was obtained up to 10 mg L−1 of boron. The range of boron concentrations in various wine samples was 4.2–10.8 mg L−1.

Prediction of Wine Sensorial Quality by Routinely Measured Chemical Properties

Abstract The determination of the sensorial quality of wines is of great interest for wine consumers and producers since it declares the quality in most of the cases. The sensorial assays carried out by a group of experts are time-consuming and expensive especially when dealing with large batches of wines. Therefore, an attempt was made to assess the possibility of estimating the wine sensorial quality with using routinely measured chemical descriptors as predictors. For this purpose, 131 Slovenian red wine samples of different varieties and years of production were analysed and correlation and principal component analysis were applied to find inter-relations between the studied oenological descriptors. The method of artificial neural networks (ANNs) was utilised as the prediction tool for estimating overall sensorial quality of red wines. Each model was rigorously validated and sensitivity analysis was applied as a method for selecting the most important predictors. Consequently, acceptable results were obtained, when data representing only one year of production were included in the analysis. In this case, the coefficient of determination (R2) associated with training data was 0.95 and that for validation data was 0.90. When estimating sensorial quality in categorical form, 94 % and 85 % of correctly classified samples were achieved for training and validation subset, respectively.

Determination of fluorine in Turkish wines by molecular absorbance of CaF using a high resolution continuum source atomic absorption spectrometer

Fluorine contents of different types of wines produced in Turkey were determined by the molecular absorption of calcium mono-fluoride (CaF) using a high resolution continuum source graphite furnace atomic absorption spectrometer (HR-CS GFAAS). For this purpose, 2000 μg mL−1 of calcium was co-injected to the graphite furnace with diluted wine samples. In order to increase the sensitivities and reduce the limit of detection (LOD) and characteristic mass, summation of the absorbances for CaF at 606.440 nm and 606.231 nm were evaluated. Graphite furnace program was optimized for best accuracy and 700 °C for pyrolysis, 2250 °C for molecule forming temperature was selected. Quantification was made by linear calibration, standard addition technique by HR-CS-AAS and the results were also compared with ISE method and no significant difference was found. The range of F contents for 20 red and white wine samples varies between LOD and 0.38 mg L−1. The limit of detection and characteristic mass of the method were 0.18 and 0.058 ng of F, respectively which are appropriate to detect the fluorine concentrations in most of the wine samples. The method is simple, fast, accurate and sensitive.

Using of molecularly imprinted polymers for determination of gallic and protocatechuic acids in red wines by high performance liquid chromatography

The sorption capacities of gallic- and protocatechuic acid-molecularly imprinted polymers (GA-MIP and PCA-MIP, respectively) and non-imprinted polymer (NIP) have been determined on the piston columns by the frontal analyses (FAs). Mobile phases consisted of MeOH, MeOH/H2O (1:1), 12.5% EtOH or ACN. Solutes concentrations used in FAs were 1μg/mL and 50μg/mL. All sorption capacities were depended on analyte and solvent used. Results obtained from the FAs have shown that both imprinted polymers almost always were preferentially recognized PCA molecule. Only in MeOH, the GA-MIP had ability to recognize its template molecule positively. Surprisingly, in some cases, also the NIP exhibited higher sorption capacities than the MIPs for their templates, e.g. in ACN for GA or in MeOH for PCA. This behaviour indicates that in some solvents, the low affinity sites of the blank polymer can act as strong interacting sites. In the next, prepared MIPs were successfully used as the SPE-sorbents for the extraction and purification of chosen phenolic acids from red wine samples. The recoveries both of MIPs were the highest for PCA, what was in agreement with the experiments carried out in 12.5% EtOH during FAs. Prepared MIP-beads allowed the purification of chosen red wine samples with satisfactory selectivities and high recoveries. The linearity of the method was in the range from 10μg/mL to 70μg/mL and 0.1μg/mL to 4.5μg/mL for GA and PCA, respectively, with the determination coefficients ranging from 0.996–0.999. The LODs (S/N=3) ranged from 0.1μg/mL to 0.4μg/mL. The RSDs for the recoveries varied from 4.0% to 8.1%. The PAs-MIPs and corresponding NIP were also characterized by attenuated total reflectance analysis Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron analysis (SEM).

Carbon nanotubes for voltammetric determination of sulphite in some beverages

In this work, a square-wave voltammetric method based on sulphite electrochemical reduction was developed for quantification of this preservative in commercial beverages. A carbon-paste electrode chemically modified with multiwalled carbon nanotubes was used as the working electrode. Under the optimised experimental conditions, a linear response to sulphite concentrations from 1.6 to 32mgSO2L−1 (25–500μmolL−1 of sulphite), with a limit of detection of 1.0mgSO2L−1 (16μmolL−1 of sulphite), was obtained. This method does not suffer interference from other common beverage additives such as ascorbic acid, fructose, and sucrose, and it enables fast and reliable sulphite determination in beverages, with minimal sample pretreatment. Despite its selectivity, the method is not applicable to red grape juice or red wine samples, because some of their components produce a cathodic peak at almost the same potential as that of sulphite reduction.

Amplified fluorescent aptasensor through catalytic recycling for highly sensitive detection of ochratoxin A

This paper describes a novel approach utilizing nano-graphite–aptamer hybrid and DNase I for the amplified detection of ochratoxin A (OTA) for the first time. Nano-graphite can effectively quench the fluorescence of carboxyfluorescein (FAM) labeled OTA specific aptamer due to their strong π–π; stacking interactions; while upon OTA addition, it will bind with aptamer to fold into an OTA–aptamerG-quadruplex structure, which does not adsorb on the surface of nano-graphite and thus retains the dye fluorescence. Meanwhile, the G-quadruplex structure can be cleaved by DNase I, and in such case OTA is delivered from the complex. The released OTA then binds other FAM-labeled aptamers on the nano-graphite surface, and touches off another target recycling, resulting in the successive release of dye-labeled aptamers from the nano-graphite, which leads to significant amplification of the signal. Under the optimized conditions, the present amplified sensing system exhibits high sensitivity toward OTA with a limit of detection of 20nM (practical measurement), which is about 100-fold higher than that of traditional unamplified homogeneous assay. Our developed method also showed high selectivity against other interference molecules and can be applied for the detection of OTA in real red wine samples. The proposed assay is simple, cost-effective, and might open a door for the development of new assays for other biomolecules. This aptasensor is of great practical importance in food safety and could be widely extended to the detection of other toxins by replacing the sequence of the recognition aptamer.

Fluorescent carbon nanodots for sensitive and selective detection of tannic acid in wines

Herein we describe an easy one step synthesis of carbon nanodots (C-dots) by thermal carbonization of 6-bromohexylboronic acid using two different amine compounds, polyethyleneglycol bis(3-aminopropyl (PEGA) and 1,2-aminopropane (DPA), at 180°C in atmospheric oxygen. The as-synthesized C-dots were characterized by FTIR, HRTEM, NMR and fluorescence. The C-dots prepared using PEGA showed a strong emission at 440nm with excitation at 362nm. These C-dots exhibited analytical potential as sensing probes for tannic acid (TA) determination. pH effect, interferences, and analytical performance of the method were investigated. The method was found effective in the linear concentration range from 0.1 to 10mgL−1 TA achieving a limit of detection equal 0.018mgL−1 TA. The applicability of the method was demonstrated by direct measurements of TA in red and white wine samples. Validation of the method was achieved by spiking the wine samples with different standard TA concentrations obtaining recoveries in the range (90–112.5%). A probable mechanism by which TA quenched the C-dots fluorescence was proposed.

A novel solid phase extraction – Ultra high performance liquid chromatography–tandem mass spectrometry method for the quantification of ochratoxin A in red wines

A novel and advanced technology on solid phase extraction column prior to liquid chromatography coupled to tandem mass spectrometry has been used for the determination of ochratoxin A in red wine samples. Due to the need of a reliable and rugged method according to current regulations and with the aim of minimize heuristic efforts associated with analytical method development, the statistical design of experiment was employed. On other hand, the method validation according to European Commission 2002/657/EC was achieved. The values obtained for decision limit (CCα), detection capability (CCβ), limits of detection and quantification were 0.07μgL−1, 0.14μgL−1, 0.13μgL−1 and 0.41μgL−1, respectively. The recoveries values were ranged from 95.7% to 107.2%. These values were compatible with the 2.0μgL−1 maximum allowable concentration limit established by different international regulations.

Pillarene functionalized polymer monolithic column for the solid-phase microextraction preconcentration of parabens

Poly(glycidyl methacrylate-co-ethylene dimethacrylate) modified with a new supramolecular macrocycle, carboxylatopillar[5]arene, was successfully prepared inside a capillary. The functionalized polymer monolith material was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Fourier-transformed infrared spectra. The experimental results showed that this type of polymer possess a good network skeleton structure and excellent extraction properties for the enrichment of parabens by polymer monolith solid-phase microextraction coupled with high performance liquid chromatography. Compared with other pre-treatment methods, the simple operation and inexpensive instrumentation characteristics of the developed polymer monolith SPME method make it more suitable for the extraction of parabens in red wine samples with great potential for further broadening its applications in the enrichment of other real samples.

Dinuclear copper(II) octaazamacrocyclic complex in a PVC coated GCE and graphite as a voltammetric sensor for determination of gallic acid and antioxidant capacity of wine samples

A novel efficient differential pulse voltammetric (DPV) method for determination gallic acid (GA) was developed by using an electrochemical sensor based on [Cu2tpmc](ClO4)4 immobilized in PVC matrix and coated on graphite (CGE) or classy carbon rod (CGCE). The proposed method is based on the gallic acid oxidation process at formed [Cu2tpmcGA]3+ complex at the electrode surface. The complexation was explored by molecular modeling and DFT calculations. Voltammograms for both sensors, recorded in a HNO3 as a supporting electrolyte at pH 2 and measured in 2.5×10−7 to 1.0×10−4M of GA, resulted with two linear calibration curves (for higher and lower GA concentration range). The detection limit at CGE was 1.48×10−7M, while at CGCE was 4.6×10−6M. CGE was successfully applied for the determination of the antioxidant capacity based on GA equivalents for white, rosé and red wine samples.

A glassy carbon electrode modified by a copolymer of Co-tetrakis (para-aminophenyl)porphyrin and ortho-phenylenediamine. Characterization and electrocatalytic sulfite oxidation behavior of a basic extract from red wine

In this work, we present a comparison among three glassy carbon electrodes modified by Co-porphyrin, ortho-phenylenediamine, or both simultaneously. This comparison shows the differences among the electrochemical behavior, morphological characteristics and electrocatalytic behavior toward the sulfite oxidation of these electrodes. The electrode modified by Co-porphyrin, ortho-phenylenediamine and copolymer has been investigated in detail for the comparision of electrocatalytic activity towards the sulfite oxidation. In the case of the glassy carbon-modified electrodes, the presence of the copolymer enhances the electrocatalytic performance of the modified electrodes in spite of the non-catalytic response (compared to the bare glassy carbon) of both homopolymer-modified electrodes toward the oxidation of sulfite. Additionally, the oxidation of sulfite extracted from red wine is shown. The copolymer-modified electrode is capable of oxidizing the extracted free sulfite in a 0.02 M NaOH solution. Through the addition of standards method, a concentration of free sulfite in a Chilean red wine sample was determined to be 44 ppm.

The integrated quality assessment of Chinese commercial dry red wine based on a method of online HPLC-DAD-CL combined with HPLC-ESI-MS

AimTo apply an integrated quality assessment strategy to investigate the quality of multiple Chinese commercial dry red wine samples. MethodA comprehensive method was developed by combining a high performance liquid chromatography-diode array detector-chemiluminescence (HPLC-DAD-CL) online hyphenated system with an HPLC-ESI-MS technique. ResultsChromatographic and H2O2-scavenging active fingerprints of thirteen batches of different, commercially available Chinese dry red wine samples were obtained and analyzed. Twenty-five compounds, including eighteen antioxidants were identified and evaluated. The dominant and characteristic antioxidants in the samples were identified. The relationships between antioxidant potency and the cultivated variety of grape, producing area, cellaring period, and trade mark are also discussed. ConclusionThe results provide the feasibility for an integrated quality assessment strategy to be efficiently and objectively used in quality (especially antioxidant activity) assessment and identification of dry red wine

Malate quinone oxidoreductase biosensors based on tetrathiafulvalene and gold nanoparticles modified screen-printed carbon electrodes for malic acid determination in wine

Screen-printed carbon electrodes have been modified with gold nanoparticles, tetrathiafulvalene and malate quinone oxidoreductase enzyme for the sensitive and selective detection of malic acid. Amperometric experimental conditions were optimized taking into account the importance of quantifying malic acid in wine samples and the inherent complexity of these samples, particularly red wine. The biosensor responds to malic acid giving an anodic current (at +100mV and pH 6.5) in a wide concentration range, with a capability of detection of 2.0μM (α=β=0.05) at room temperature. The method has been applied to the determination of malic acid in white, rose and red wine samples, with averages recoveries of 99.6%.

Metabolic fingerprinting based on high-resolution tandem mass spectrometry: a reliable tool for wine authentication?

Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (MS) and an alternative technology represented by direct analysis in real time coupled with quadrupole time-of-flight MS were investigated for metabolic fingerprinting of 343 red and white wine samples. Direct injection of pure wine and an extraction procedure optimized for isolation of polyphenols were used to compare different analytical and data handling strategies. After data processing and data pretreatment, principal component analysis was initially used to explore the data structure. Initially, the unsupervised models revealed a notable clustering according to the grape varieties, and therefore supervised orthogonal partial least squares discriminant analysis models were created and validated for separation of red and white wines according to the grape variety. The validated orthogonal partial least squares discriminant analysis models based on data (ions) recorded in positive ionization mode were able to classify correctly 95% of samples. In parallel, authentication parameters, such as origin and vintage, were evaluated, and they are discussed. A tentative identification of markers was performed using accurate mass measurement of MS and MS/MS spectra, different software packages and different online libraries. In this way, different flavonol glucosides and polyphenols were identified as wine markers according to the grape varieties.

Rapid HPLC analysis of amino acids and biogenic amines in wines during fermentation and evaluation of matrix effect

A rapid HPLC method has been developed for the simultaneous determination of 23 amino acids, 10 biogenic amines and the ammonium ion in wine. Samples were pre-column derivatised with diethyl ethoxymethylenemalonate and separated using reversed-phase HPLC within 30min. The matrix effect was evaluated when measuring samples taken from different stages of fermentation. Most compounds showed no obvious matrix effect, whereas proline, ethanolamine and spermine had remarkably different responses to variable concentrations of sugar. High concentrations of sugar affected the pH of the derivatisation reaction system; proline, ethanolamine and spermine derivatives were sensitive to this effect. Matrix-matched calibration was used for the quantification of these compounds. Validation of the method showed that it was accurate, reproducible and efficient for the simultaneous determination of amino acids and biogenic amines in wines during fermentation. As a specific application of the method, red wine samples taken from different stages of fermentation were analysed.

Phenolic profile of Douro wines and evaluation of their [rad]NO scavenging capacity in LPS-stimulated RAW 264.7 macrophages

The phenolic profile of two samples of commercial Douro red wines, a table red wine (RM) and a Port wine (PR), was analysed by HPLC-DAD after purification by solid phase extraction (SPE). Eighteen phenolic compounds belonging to benzoic acids, hydroxycinnamic acids and anthocyanins were determined. The presence of tannins in both wines and of polymeric anthocyanins in Port wine could be inferred by the chromatograms registered at 280 and 500nm, respectively. The wine extracts showed capacity to scavenge sodium nitroprusside-released nitric oxide (NO), RM being more effective than PR, which can be partly attributed to its higher content in monomeric anthocyanins. Using a model of macrophages (RAW 264.7 cells) stimulated with bacterial lipopolysaccharide (LPS) the samples showed a similar potential, which may indicate the importance of polymeric anthocyanins and the higher amount of phenolic acids present in PR to decrease cells NO levels.

Fast determination of seven synthetic pigments from wine and soft drinks using magnetic dispersive solid-phase extraction followed by liquid chromatography–tandem mass spectrometry

A novel, simple and sensitive method based on the use of magnetic dispersive solid-phase extraction (M-dSPE) procedure combined with ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC–MS/MS) was developed to determine seven synthetic pigments (tartrazine, amaranth, carmine, sunset yellow, allura red, brilliant blue and erythrosine) in wines and soft drinks. An amino-functionalized low degrees of cross-linking magnetic polymer (NH2-LDC-MP) was synthesized via suspension polymerization, and characterized by transmission electron microscopy (TEM). The NH2-LDC-MP was used as the M-dSPE sorbent to remove the matrix from the solution, and the main factors affecting the extraction were investigated in detail. The obtained results demonstrated the higher extraction capacity of NH2-LDC-MP with recoveries between 84.0 and 116.2%. The limits of quantification (LOQs) for the seven synthetic pigments were between 1.51 and 5.0μg/L in wines and soft drinks. The developed M-dSPE UFLC–MS/MS method had been successfully applied to the real wines and soft drinks for food-safety risk monitoring in Zhejiang Province, China. The results showed that sunset yellow was in three out of thirty soft drink samples (2.95–42.6μg/L), and erythrosine in one out of fifteen dry red wine samples (3.22μg/L), respectively. It was confirmed that the NH2-LDC-MP was a kind of highly effective M-dSPE materials for the pigments analyses.

Preparation of poly(butyl methacrylate-co-ethyleneglyceldimethacrylate) monolithic column modified with β-cyclodextrin and nano-cuprous oxide and its application in polymer monolithic microextraction of polychlorinated biphenyls

A poly(butyl methacrylate-co-ethyleneglyceldimethacrylate) (poly(BMA-EDMA)) monolithic column was prepared with in situ polymerization method and modified with allylamine-β-cyclodextrin (ALA-β-CD) and nano-cuprous oxide (Cu2O). A polymer monolith microextraction method was developed with the modified monolithic column for the preconcentration of polychlorinated biphenyls combined with gas chromatography–electron capture detector. Various parameters affecting the extraction efficiency were investigated and optimized. Under the optimum experimental conditions, we obtained acceptable linearities, low limits of detection, and good intra-day/inter-day relative standard deviations. Because of the hydrophobic properties of β-CD and the porous nano structure of Cu2O, the enrichment capacity of the poly(BMA-EDMA) monolithic column was significantly improved. The extraction efficiency followed the order: poly(BMA-EDMA-ALA-β-CD-Cu2O)>poly(BMA-EDMA-ALA-β-CD)>poly(BMA-EDMA)>direct GC analysis. When applied to the determination of polychlorinated biphenyls in wine samples, low limits of detection (0.09ngmL−1) were obtained under the preoptimized conditions (sample volume 1.0mL, sample flow rate 0.1mLmin−1, eluent volume 0.1mL, and eluent flow rate 0.05mLmin−1). In addition, the present method was employed to determine polychlorinated biphenyls in red wine samples and the accuracy was assessed through recovery experiments. The obtained recovery values were in the range of 78.8–104.1% with relative standard deviations less than 9.0%.

Brettanomyces yeasts isolated from lebanese wines showing difference in their molecular pattern

The action of Brettanomyces yeast is a leading cause for organoleptic alterations of wine. To evaluate the presence of this yeast in Lebanon, 100 red wine samples selected from 14 wineries located in different regions of the Lebanese territory, were analyzed. Only 3 samples gave positive results. A first PCR showed that all isolates belonged to the species B. bruxellensis. Strains profiles were compared to 2 other French isolates. The PCR-RFLP was then used with 3 endonucleases for an inter-species characterization. The obtained results revealed a degree of polymorphism between strains isolated from different geographical origins. A comparison of the sequence of ITS regions, including the 5.8S rDNA and partial sequences of 18S and 28S rDNA illustrate potential similarities or differences between strains belonging to the same group.