Real Wine Research Articles

Electrochemiluminescence recovery-based aptasensor for sensitive Ochratoxin A detection via exonuclease-catalyzed target recycling amplification

Based on the recovery of the quantum dot (QD) electrochemiluminescence (ECL) and exonuclease-catalyzed target recycling amplification, the development of a highly sensitive aptasensor for Ochratoxin A (OTA) detection is described. The duplex DNA probes containing the biotin-modified aptamer are immobilized on a CdTe QD composite film-coated electrode. The presence of the OTA target leads to effective removal of the biotin–aptamers from the electrode surface via exonuclease-catalyzed recycling and reuse of OTA, which prevents the attachment of streptavidin–alkaline phosphatase (STV–ALP) through biotin–STV interaction. The electron transfer (ET) from the excited state CdTe QD ([CdTe]⁎) to the electro-oxidized species of the enzymatic product of ALP during the potential scan is thus inhibited and the QD ECL emission is restored for quantitative OTA detection. Due to the exonuclease-catalyzed target recycling amplification, the inhibition effect of ET is significantly enhanced to achieve sensitive detection of OTA down to 0.64pgmL−1. The proposed method is selective for OTA and can be used to monitor OTA in real red wine samples. Our developed ECL recovery-based aptasensor thus offers great potential for the development of new ECL sensing platforms for various target analytes.

Direct potentiometric quantification of histamine using solid-phase imprinted nanoparticles as recognition elements

A new potentiometric sensor based on molecularly imprinted nanoparticles produced via the solid-phase imprinting method was developed. For histamine quantification, the nanoparticles were incorporated within a membrane, which was then used to fabricate an ion-selective electrode. The use of nanoparticles with high affinity and specificity allowed for label-free detection/quantification of histamine in real samples with short response times. The sensor could selectively quantify histamine in presence of other biogenic amines in real wine and fish matrices. The limit of detection achieved was 1.12×10−6molL−1, with a linear range between 10−6 and 10−2molL−1 and a response time below 20s, making the sensor as developed a promising tool for direct quantification of histamine in the food industry.

Binding-induced autonomous disassembly of aptamer–DNAzyme supersandwich nanostructures for sensitive electrochemiluminescence turn-on detection of ochratoxin A

The self-assembled DNA nanostructure has been one of the most interesting research areas in the field of nanoscience, and the application of the DNA self-assembled nanostructures in biosensing is still in the early stage. In this work, based on the target-induced autonomous disassembly of the aptamer-DNAzyme supersandwich nanostructures, we demonstrated a highly sensitive strategy for electrochemiluminescent (ECL) detection of ochratoxin A (OTA). The aptamer-DNAzyme supersandwich nanostructures, which exhibited significant ECL quenching effect toward the oxygen/persulfate (O2/S2O8(2-)) system, were self-assembled on the gold electrode surface. The presence of the target OTA and the exonuclease (RecJf) resulted in autonomous disassembly of the nanostructures and cyclic reuse of OTA, leading to efficient recovery of the ECL emission and highly sensitive detection of OTA. 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, which offers the proposed method opportunities for designing new DNA-based nanostructures for biosensing applications.

Rapid analysis of fungicides in white wines from Northwest Spain by ultrasound-assisted emulsification-microextraction and gas chromatography-mass spectrometry

A rapid, efficient and low-cost method based on ultrasound-assisted emulsification-microextraction (USAEME) and gas chromatography-mass spectrometry was developed for the analysis of several fungicides, belonging to different chemical families, in white wines. The experimental procedure was optimized using factorial design to study the influence of the solvent type, extraction time, extraction temperature, sample, pH, and salt addition on the extraction efficiency. Under the selected conditions, compounds were extracted into 200 μL chloroform from 10 mL of wine sample in only 5 min at ambient temperature. The method was validated using real wine samples, with fungicide recoveries generally ranging from 70 to 115%, good intra- and inter-day precision (relative standard deviation (RSD) values ≤12%), and limits of detection at the sub-ng per millilitre level (LOD ≤ 0.1 ng mL−1). The application of the method to varietal wines belonging to different brands showed the presence of fungicides in all samples at concentrations ranging from 1 to 700 ng mL−1, with a minimum of two and a maximum of seven chemicals per sample.

Nanostructured enzymatic biosensor based on fullerene and gold nanoparticles: Preparation, characterization and analytical applications

In this work a novel electrochemical biosensing platform based on the coupling of two different nanostructured materials (gold nanoparticles and fullerenols) displaying interesting electrochemical features, has been developed and characterized. Gold nanoparticles (AuNPs) exhibit attractive electrocatalytic behavior stimulating in the last years, several sensing applications; on the other hand, fullerene and its derivatives are a very promising family of electroactive compounds although they have not yet been fully employed in biosensing. The methodology proposed in this work was finalized to the setup of a laccase biosensor based on a multilayer material consisting in AuNPs, fullerenols and Trametes versicolor Laccase (TvL) assembled layer by layer onto a gold (Au) electrode surface.The influence of different modification step procedures on the electroanalytical performance of biosensors has been evaluated. Cyclic voltammetry, chronoamperometry, surface plasmon resonance (SPR) and scanning tunneling microscopy (STM) were used to characterize the modification of surface and to investigate the bioelectrocatalytic biosensor response. This biosensor showed fast amperometric response to gallic acid, which is usually considered a standard for polyphenols analysis of wines, with a linear range 0.03–0.30mmolL−1 (r2=0.9998), with a LOD of 0.006mmolL−1 or expressed as polyphenol index 5.0–50mgL−1 and LOD 1.1mgL−1. A tentative application of the developed nanostructured enzyme-based biosensor was performed evaluating the detection of polyphenols either in buffer solution or in real wine samples.

Immobilized pineapple stem bromelain activity in a wine-like medium: Effect of inhibitors

The catalytic activity of stem bromelain, covalently immobilized on chitosan beads, was characterized towards a synthetic substrate (Bz-Phe-Val-Arg-pNA), in a wine-like acidic medium containing wine inhibitors (ethanol, sulphur dioxide, grape skin and seed tannins), at their average concentration range.For all tested substances, the inhibition constant (Ki) values of immobilized bromelain were significantly higher than the corresponding values obtained in a previous work for free enzyme, thus indicating that direct covalent immobilization on chitosan beads makes protease more resistant to the inhibition effect.Immobilized protease was affected by ethanol inhibition (competitive type) only if present at abnormal concentration for real wine. Grape skin and seed tannins exerted uncompetitive inhibition to the same extent, with a Ki value close to 1 g lgallic acid eq−1. The effect of free sulphur dioxide on immobilized bromelain changed respect to free enzyme, both becoming uncompetitive inhibitor and dramatically lowering its strength.These results show that immobilized stem bromelain could have productive biotechnological applications in winemaking, even though further studies will be necessary to test its proteolytic activity towards wine proteins in real matrices.

Investigation and correction of the interference of ethanol, sugar and phenols on dissolved oxygen measurement in wine

The dissolved oxygen in wine is routinely measured to control and monitor various oenological processes. The availability of devices based on different technologies and features allows a user to select a device that best meets their needs. However, grape must and wine samples each exhibit a complex composition that varies with time, which, along with atmospheric conditions, makes it necessary to evaluate the effects of these factors on dissolved oxygen measurements. This work evaluates the effects that ethanol, sugar, and phenols have on dissolved oxygen measurements in a model and real wine. The results suggest that significant errors are made in all studied systems and that the response of each device is different. Therefore, a compensation value was developed to take into account the sample composition. A compensation value was proposed to minimise the error made by each device based on the ethanol and sugar contents of the measured liquid. The best results are those obtained after using the compensation value to correct the data from the Pyro-Mini device. In all cases, errors made in DO measurements by optical systems were reduced by 50–82% by applying the compensation value for synthetic wines and 45–100% for real wines.

Development of a simple fluorescence-based microplate method for the high-throughput analysis of proline in wine samples

This paper presents a simple, accurate and multi-sample method for the determination of proline in wines thanks to a 96-well microplate technique. Proline is the most abundant amino acid in wine and is an important parameter related to wine characteristics or maturation processes of grape. In the current study, an improved application of the general method based on sodium hypochlorite oxidation and o-phthaldialdehyde (OPA)-thiol spectrofluorometric detection is described. The main interfering compounds for specific proline detection in wines are strongly reduced by selective reaction with OPA in a preliminary step under well-defined pH conditions. Application of the protocol after a 500-fold dilution of wine samples provides a working range between 0.02 and 2.90gL−1, with a limit of detection of 7.50mgL−1. Comparison and validation on real wine samples by ion-exchange chromatography prove that this procedure yields accurate results. Simplicity of the protocol used, with no need for centrifugation or filtration, organic solvents or high temperature enables its full implementation in plastic microplates and efficient application for routine analysis of proline in wines.

Magnetic Stirring-Assisted Dispersive Suspended Microextraction with Solidification of a Floating Organic Droplet for the Determination of Trace Fungicides in Water and Wine

For the first time, a simple method for magnetic stirring-assisted dispersive suspended microextraction has been developed for the determination of three fungicides (azoxystrobin, diethofencarb, and pyrimethanil) in water and wine samples. The method is based on the solidification of a floating organic droplet coupled with high performance liquid chromatography. In the proposed method, the low toxicity solvent 1-dodecanol was used as the extractant. Both the extraction and phase separation process were performed with magnetic stirring. No centrifugation step was involved. After separating the two phases, the extraction solvent droplet was easily collected through solidification at lower temperature. Important parameters such as the kind and volume of organic extraction solvent, extraction and restoration speed, extraction and restoration time, and salt concentration were optimized. Under the optimal conditions, the limits of detection for the analytes varied from 0.14 to 0.26 µg L−1. The enrichment factors ranged from 125–200. The linearity ranges were 1–2000 µg L−1, yielding correlation coefficients (r) higher than 0.9990. The relative standard deviation (n = 6) at two spiked level of 0.2 µg mL−1 and 4 µg L−1 varied between 2.2% and 7.8%. Finally, the developed technique was successfully applied to determine target fungicides in real water and wine samples, where the obtained recoveries ranged from 83.8–105.3%

Membrane dealcoholization of different wine varieties reducing aroma losses. Modeling and experimental validation

Abstract This work reports the analysis of the performance of a membrane pilot plant aimed at the partial dealcoholization, reducing 2% v/v the alcoholic content, of wine varieties (Garnacha and Xarelo). The evaporative pertraction (EP) process has been experimentally and theoretically analyzed resulting in a mathematical model and set of parameters that can be used to search for the optimum operational conditions as a function of the feed wine characteristics. A compromise solution between ethanol reduction and aroma compounds preservation was the main difficulty to overcome. As a result under the selected working conditions the model predicts aroma compound losses below 20% whereas keeping the dealcoholization ratio, thus showing a huge improvement in comparison with previous data found in the literature (aroma losses between 30 and 50%). Industrial relevance Nowadays the alcohol content in wines is constantly increasing affecting the final quality of the product. The current techniques applied in the industry to adjust the alcohol content (Spinning Cone Column and Reverse Osmosis) demand high energy consumptions. The Evaporative Pertraction (EP) technique proposed in this work is a membrane based technology that requires low energy. The present experimental and theoretical evaluation of EP at large scale in partial dealcoholization of different real wine varieties has proved that aroma compound losses can be quantitatively reduced to acceptable values for industry applications (

Acetobacter malorum and Acetobacter cerevisiae identification and quantification by Real-Time PCR with TaqMan-MGB probes

The identification and quantification of Acetobacter malorum and Acetobacter cerevisiae in wine and vinegar were performed using the Real-Time PCR (RT-PCR) with two TaqMan-MGB probes designed to amplify the internal transcribed spacer (ITS) region between the 16S–23S rRNA genes. The primers and probes were highly specific, with a detection limit of 102 cells/ml for both species, and the efficiency of the technique was >80%. The RT-PCR technique with these two new TaqMan-MGB probes, together with the five (Acetobacter aceti, Acetobacter pasteurianus, Gluconobacter oxydans, Gluconacetobacter hansenii and Gluconacetobacter europaeus) that are already available (Torija et al., 2010), were validated on known concentrations of Acetic Acid Bacteria (AAB) grown in glucose medium (GY) and in inoculated matrices of wine and vinegar. Furthermore, this technique was applied to evaluate the AAB population in real wine samples collected in the Canary Islands. PCR enrichment performed prior to RT-PCR increased the accuracy of quantification and produced results similar to those detected with SYBR-Green. In real wine samples, the total AAB enumeration ranged from 9 × 102 to 106 cells/ml, and the seven AAB species tested were detected in more than one sample. However, AAB recovery on plates was poor; the isolates obtained on plates were A. malorum, G. oxydans, A. cerevisiae and A. pasteurianus species. RT-PCR with TaqMan-MGB probes is an accurate, specific and fast method for the identification and quantification of AAB species commonly found in wine and vinegar.

Preparation of magnetic molecularly imprinted polymer for selective recognition of resveratrol in wine

The magnetic molecularly imprinted polymers (MMIPs) for resveratrol were prepared by using surface molecular imprinting technique with a super paramagnetic core–shell nanoparticle as a supporter. Rhapontigenin, which is the analogues of resveratrol, was selected as dummy template molecules to avoid the leakage of trace amount of resveratrol. Acrylamide and ethylene glycol dimethacrylate were chosen as functional monomers and cross-linker, respectively. The obtained MMIPs were characterized by using scanning electron microscopy, Fourier transform infrared spectrum, X-ray diffraction and vibrating sample magnetometer. High performance liquid chromatography was used to analyze the target analytes. The resulting MMIPs exhibited high saturation magnetization of 53.14emug−1 leading to the fast separation. The adsorption test showed that the MMIPs had high adsorption capacity for resveratrol and contained homogeneous binding sites. The MMIPs were employed as adsorbent of solid phase extraction for determination of resveratrol in real wine samples, and the recoveries of spiked samples ranged from 79.3% to 90.6% with the limit of detection of 4.42ngmL−1. The prepared MMIPs could be employed to selectively pre-concentrate and determine resveratrol from wine samples.

Determination of the Complexing Capacity of Wine for Zn Using the Absence of Gradients and Nernstian Equilibrium Stripping Technique

The complexing capacity of synthetic (0.011 M tartrate in 13.5% ethanol) and real wine (Raimat Abadia) in titrations with added total Zn concentrations up to 0.03 M has been determined following the free Zn concentrations with AGNES (absence of gradients and Nernstian equilibrium stripping) technique. A correction to find the preconcentration factor or gain (Y(1)) really applied at each one of the ionic strengths reached due to Zn additions along the titration has been applied. The standard implementation of AGNES to real wine led to the observation of two anomalous behaviors: (a) an increasingly negative current in the deposition stage (labeled as "HER" effect) and (b) a minimum in the currents of the stripping stage plot (labeled as the "dip" effect). A practical strategy to apply AGNES avoiding the dip effect has been developed to quantify properly free Zn concentrations. The van den Berg-Ružic-Lee linearization method (assuming the existence of just 1:1 complexes) has been adapted to consider the dilution effect and the ionic strength changes. Aggregated stability constants and total ligand concentrations have been calculated from synthetic and wine titration data. The found complexing capacity in the studied wine (c(T,L) = 0.0179 ± 0.0007 M) indicates the contribution of ligands other than tartrate (which is confirmed to be the main one).

Pineapple stem bromelain immobilized on different supports: Catalytic properties in model wine

Bromelain from pineapple stem has been covalently immobilized on different supports to select the more efficient biocatalyst that should be applied toward unstable proteins in real white wine. In this preliminary study, catalytic properties of different immobilized bromelain forms were compared under wine-like conditions, against a synthetic substrate (Bz-Phe-Val-Arg-pNA).Covalent immobilization affected protease kinetic properties, even if all immobilized forms presented both a better substrate affinity and higher half-life (with the exception of a few procedures) with respect to the free enzyme. Stem bromelain was successfully immobilized on chitosan beads without glutaraldehyde thus yielding a food-safe and promising biocatalyst for unstable real wine future application.

Application of dispersive solid-phase extraction and ultra-fast liquid chromatography–tandem quadrupole mass spectrometry in food additive residue analysis of red wine

A novel and effective dispersive solid-phase extraction (dSPE) procedure with rapid magnetic separation using ethylenediamine-functionalized magnetic polymer as an adsorbent was developed. The new procedure had excellent clean-up ability for the selective removal of the matrix in red wine. An accurate, simple, and rapid analytical method using ultra-fast liquid chromatography–tandem quadrupole mass spectrometry (UFLC–MS/MS) for the simultaneous determination of nine food additives (i.e., acesulfame, saccharin, sodium cyclamate, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid, and neotame) in red wine was also used and validated. Recoveries ranging from 78.5% to 99.2% with relative standard deviations ranging from 0.46% to 6.3% were obtained using the new method. All target compounds showed good linearities in the tested range with correlation coefficients (r) higher than 0.9993. The limits of quantification for the nine food additives were between 0.10μg/L and 50.0μg/L. The proposed dSPE–UFLC–MS/MS method was successfully applied in the food-safety risk monitoring of real red wine in Zhejiang Province, China.

Optimisation of ultrasound-assisted emulsification microextraction method with solidification of floating organic drop for the analysis of cork taint responsible compounds in wine

This paper presents the optimisation of a method based on ultrasound assisted-emulsification method (USAEME) combined with solidification of floating organic drop (SFOD) for the sensitive determination of cork taint responsible compounds in wine. Haloanisoles (2,4,6-trichloranisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA), 2,4,6-tribromoanisole (TBA) and pentachloranisole (PCA)) and their halophenolic precursors were determined by gas chromatography with electron capture detection (GC-ECD). The derivatisation of the halophenols was performed simultaneously with the extraction. To perform the optimisation, the main parameters affecting both extraction and derivatisation were exhaustively studied in different steps. Once the extraction solvent and the pH and time conditions had been determined, experimental design was applied for the simultaneous study of the volumes of acetic anhydride and extraction solvent, temperature and ionic strength conditions. Then, the analytical characteristics of the optimised method were evaluated achieving satisfactory linearity (with correlation coefficients over 0.984), repeatability (below 10.7%) and inter-day precision (below 10.6%) for all target analytes. Moreover, detection limits found were similar or even lower than the olfactory threshold of the studied compounds. Finally, the applicability of the proposed method was tested by analysing real wine samples. To the best of our knowledge, this is the first time that USAEME–SFOD method has been used to determine cork taint responsible compounds in wine.

A Loss of Tone

A Loss of Tone B. D'J Pancake (bio) Guest Editor's Note: "A Loss of Tone" appears in the U.Va. papers. Under the title in the typescript are the words "By: B. D'J Pancake." This signature and the style of the story suggest a composition date in the mid to late 1970s. The contextual content appears to come straight out of one of Breece's favorite pastimes as a youngster in Milton: sitting on the Old Bank steps listening to the old-timers tell stories. As I walk to our shop, I think what a fine town Rock Camp really is and how well the early light strikes the bricks on Front Street and mingles again with the haze that spreads up at night from the Mud River. It is an old town, but its history is very calm. There were no Indian Wars here, only a grist-mill to draw the settler into rich corn and cane lands, and in the years to follow, the Civil War was only a popping far off in the hills. I think of my great-grandfather selling dry goods and notions from his wagon right here on Front Street, then building the shop to be handed down. I turn the corner at the Old Bank and see Willy Foutz sitting on the steps, sunning in the pink morning haze. He retired from the C&O Railroad when I was just a boy, but he still wears his fireman's clothes, brags about the accuracy of his watch. I take to the step beside him, lean back to soak in the warmth. Willy is no fool, it's good to sit this way a few minutes every morning before going on with your business. "Know what I seen yesterday?" he says. "A high-yellow, but a nigger just the same. Lives in that new bunch of houses other side of the river." "Well, it won't hurt anything. There have never been any Negroes in Rock Camp that I remember." "Was too. Raymond what's-his-name who cooked at the Justice Inn was black as your hat. Damn good cook, too, but he was awful bad to drink. Drank... [End Page 36] "Willy, the Justice Inn closed thirty years before I was born." "Drank real sweet wine for breakfast. Used to tell Mrs. Justice he was cooking with the stuff. Ain't that something?" "What became of Raymond?" "Militia ran him out because he—they claimed—got to chasing after white girls. Too bad, too. The Inn went to hell in a handcar after that." "I always thought there were no Negroes here because there was no slavery in this part of West Virginia." "Aw, hell, there was too. I recollect one nig Paw said they hung back before the war. Hung him off the trestle over Mud River—where the Teays River Pike is now—called Tin-Bridge." "Why'd they hang him?" "Don't know for sure. Paw was just a boy back then, and I'm not sure he got his facts straight, but he claimed the nig was a slave who killed his master—chopped him up with a caneknife. The master was supposed to be Mr. Gregs, and Paw said he was give to fits and beating on his slave. Looks to me like a fellow wouldn't give to beating on the only slave he had, but from what Paw said, Mr. Gregs lit into him pretty regular. Yes sir, he even said Mr. Gregs poured salt on the welts, but I don't think he got that right. "Anyhow, it was after Mr. Gregs had whipped him for something—I don't recollect what—he was out in the field working cane and his master come upon him and commenced to yelling at him. Well, the nigger'd took about all he wanted, so he just turned that cane-knife on his master. Must of come as a shock to both of them, but the nig did have the good sense to hide in the canebreaks till after dark. What he didn't have no sense about was how to clear out of...

A simple method for total quantification of mannoprotein content in real wine samples

Mannoproteins released by yeast cells throughout the winemaking process contribute in several ways to improve wine quality. For this reason, some winemaking practices have been developed in order to increase the mannoprotein content of wine. However, monitoring of mannoprotein content of wine during these processes, or even mannoprotein quantification in the final wines, is an analytical problem not easily solved so far. Here, we report a simple and accurate method for mannoprotein quantification in wines. The method involves isolation of wine polysaccharides by size exclusion chromatography, acid hydrolysis, elimination of acid by weak anionic exchange solid phase extraction, and analysis of monosaccharides by ion exclusion HPLC. Advantages over previously existing methods include low sample volumes, possibility of parallel processing for multiple samples, absence of precipitation steps, and clear distinction between mannoproteins and other wine polysaccharides.

Development of a novel microextraction by packed sorbent-based approach followed by ultrahigh pressure liquid chromatography as a powerful technique for quantification phenolic constituents of biological interest in wines

A novel analytical approach, based on a miniaturized extraction technique, the microextraction by packed sorbent (MEPS), followed by ultrahigh pressure liquid chromatography (UHPLC) separation combined with a photodiode array (PDA) detection, has been developed and validated for the quantitative determination of sixteen biologically active phenolic constituents of wine. In addition to performing routine experiments to establish the validity of the assay to internationally accepted criteria (linearity, sensitivity, selectivity, precision, accuracy), experiments are included to assess the effect of the important experimental parameters on the MEPS performance such as the type of sorbent material (C2, C8, C18, SIL, and M1), number of extraction cycles (extract-discard), elution volume, sample volume, and ethanol content, were studied. The optimal conditions of MEPS extraction were obtained using C8 sorbent and small sample volumes (250μL) in five extraction cycle and in a short time period (about 5min for the entire sample preparation step). The wine bioactive phenolics were eluted by 250μL of the mixture containing 95% methanol and 5% water, and the separation was carried out on a HSS T3 analytical column (100mm×2.1mm, 1.8μm particle size) using a binary mobile phase composed of aqueous 0.1% formic acid (eluent A) and methanol (eluent B) in the gradient elution mode (10min of total analysis). The method gave satisfactory results in terms of linearity with r2-values>0.9986 within the established concentration range. The LOD varied from 85ngmL−1 (ferulic acid) to 0.32μgmL−1 ((+)-catechin), whereas the LOQ values from 0.028μgmL−1 (ferulic acid) to 1.08μgmL−1 ((+)-catechin). Typical recoveries ranged between 81.1 and 99.6% for red wines and between 77.1 and 99.3% for white wines, with relative standard deviations (RSD) no larger than 10%. The extraction yields of the MEPSC8/UHPLC–PDA methodology were found between 78.1 (syringic acid) and 99.6% (o-coumaric acid) for red wines and between 76.2 and 99.1% for white wines. The inter-day precision, expressed as the relative standard deviation (RSD%), varied between 0.2% (p-coumaric and o-coumaric acids) and 7.5% (gentisic acid) while the intra-day precision between 0.2% (o-coumaric and cinnamic acids) and 4.7% (gallic acid and (−)-epicatechin). On the basis of analytical validation, it is shown that the MEPSC8/UHPLC–PDA methodology proves to be an improved, reliable, and ultra-fast approach for wine bioactive phenolics analysis, because of its capability for determining simultaneously in a single chromatographic run several bioactive metabolites with high sensitivity, selectivity and resolving power within only 10min. Preliminary studies have been carried out on 34 real whole wine samples, in order to assess the performance of the described procedure. The new approach offers decreased sample preparation and analysis time, and moreover is cheaper, more environmentally friendly and easier to perform as compared to traditional methodologies.

Interactions of phenolic and volatile compounds with yeast lees, commercial yeast derivatives and non toasted chips in model solutions and young red wines

Ageing of wines on lees, the use of commercial yeast derivative products and the addition of oak chips to wine permit the release of different compounds such as mannoproteins and polysaccharides into wines during yeast autolysis. These compounds released can interact with phenolic compounds and/or aromatic compounds, also modifying wine sensory perception. For that reason, the aim of this work was to evaluate the interaction of phenolic and volatile compounds of wines with yeast lees, non-toasted oak wood chips and different commercial yeast derivative preparations in model wine solutions and in a real red wine. The results found in this study have shown that most of the phenolic and volatile compounds studied are adsorbed by wood and bound by lees in model wine solutions. However, in the model wines in general, the commercial yeast derivative products studied only interacted with the volatile compounds but not with the phenolic compounds. The adsorption of the phenolic compounds occurred in the first 15 days of treatment, remaining constant for 2 months; however, in the case of volatile compounds, these compounds initially displayed a retention effect, but after 30–60 days, the release of the previously bound compounds was instigated. The adsorption effect on the phenolic and volatile compounds in the model wine solution was not always the same as in the red wine studied, which highlights the important presence of other wine compounds in these interactions.