A survey on wines from organic viticulture from different European countries

A survey was carried out on a thousand wines from organic viticulture from different European countries. Analytical data were collected about the most used quality control parameters (e.g. alcoholic strength, reducing sugars, total acidity and pH, volatile acidity, malic and lactic acid, free and total sulfur dioxide), as well as regarding some compounds harmful for human health, such as ochratoxin A and biogenic amines. The results collected on quality control parameters were generally in agreement with the values normally detectable for conventional wines. Total sulfur dioxide was lower than 110–120 mg/L in the most of the samples and no significant correlation was found between sulfite levels and other parameters. Ochratoxin A (OTA) seemed not a generalized problem for organic wine productions: its concentration was below the European legal limit, in the 95% of the samples analyzed; nevertheless, the risk of OTA pollution seemed higher in certain southern European regions. On the other hand, biogenic amines (BA) appeared a serious problem for organic winemaking and high concentrations were found in many of the analyzed wines. They seemed connected with a bad management of malolactic fermentation, being generally associated with high pHs and volatile acidities.     

Pesticide residues and microbiological quality of bottled wines

In the study we determined the pesticide residues and microbiological quality of bottled wines. Pesticide residues in wine were analysed using the multiresidual method with GC–MS, the multiresidual method with LC–MS–MS and the method for determination of dithiocarbamate residues with GC–MS. Furthermore, the effect of bentonite and the combined fining agent on the concentration of boscalid in wine was tested. The microbiological analysis was performed using membrane filtration. Nine pesticide residues were determined in the samples. More than 50% of wines belonged to the category of wines with only up to two pesticide residues. The most frequently determined pesticide in wines was boscalid (76% of samples) followed by fenhexamid (44%). The highest concentrations of pesticide residues in wines were determined for cyprodinil (0.44 mg/L) and fludioxonil (0.21 mg/L). The combined fining agent was more efficient in lowering the concentration of boscalid in wine if compared with bentonite. The results of microbiological quality indicate that no less than one quarter of bottled wines on our store shelves is microbiologically unstable.     

A survey of biogenic amines in commercial Portuguese wines

The study of biogenic amines in wine is important because the possible toxicological risk that might result from an intake of a great quantity of these molecules and the possibility that there might exist a relationship between high amine contents and unsanitary conditions during the wine making procedures.Biogenic amines are basic nitrogenous compounds found in wine and their occurrence gives rise to significant debate because of their physiological effects in humans.The aim of this work was to evaluate the types and levels of biogenic amines in commercial Portuguese wines from different and over a period of 10 years.With this work it was possible to conclude that most commercial Portuguese wines presented a low concentration of biogenic amines (<8 mg/l) and 25% of these wines presented contents lower than 2.5 mg/l. Tyramine and putrescine were biogenic amines present in a higher concentration. The wines from the Alentejo region showed highest concentrations of biogenic amines, especially in tyramine and histamine.     

Use of a submerged yeast culture and lysozyme for the treatment of bacterial contamination during biological aging of sherry wines

The aim of this study was to determine the effect of a submerged culture of “flor” velum yeast and lysozyme as treatments against bacterial contamination by lactic acid and acetic acid bacteria during the biological aging of sherry wine. Different submerged culture treatments with lysozyme were performed. To assess these treatments, we performed laboratory assays with wine spoiled by lactic acid bacteria (LAB) and/or acetic acid bacteria (AAB) selected from the “solera” sherry wine cellar system. The results indicate that lysozyme should be added to submerged culture conditions after the start of the yeast growth phase. The application of lysozyme at a dose of 12.5 g/hL and submerged culture conditions was very effective for the treatment of advanced heterolactic fermentation during the biological aging of wines, thereby inhibiting the LAB population and reducing the volatile acidity of the wines (<0.1 g/L). Similarly, the submerged culture was a very effective tool for the treatment of AAB contamination of recovering wines with high volatile acidity and the removal of AAB without alcohol correction of the wine. The combined lysozyme and submerged culture treatment was very effective at removing bacteria from the wine, reducing volatile acidity and preventing acetification.     

Determination,content analysis and removal efficiency of fining agents on ochratoxin A in Chinese wines

A simple and convenient HPLC-FD detection method for ochratoxin A (OTA) with a high detection limit and a short run time has been developed. OTA has been found in most samples of Chinese market wine, including domestic and imported wines, but the content was not very high. Only a few wines showed an OTA content that exceeded the EC and OIV limits, indicating that most Chinese market wines were safe. The OTA intake for Chinese from wine was 0.017 ng/kg (bw) per day, which was lower than the SCF and JECFA limits and also lower than in many other countries. This was mainly due to the low per capita wine consumption in China, but it is still necessary for the Chinese government and wine makers to monitor OTA levels in wine and to establish relevant regulations. An egg white treatment (0.20 mg/mL, 48 h) was the best removal method for OTA.     

Evaluation of biogenic amines in wine: Determination by an improved HPLC-PDA method

An improved, simple and sensitive method to quantify the biogenic amines ethanolamine, methylamine, ethylamine, isoamylamine and the usually investigated β-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, spermine has been developed and validated in red and white wines. The analytes were derivatised with dansyl chloride and separated by HPLC coupled with PDA detector. The calibration curves showed good linearity (r > 0.9990) and biogenic amines recovery varied from 72 to 97%. The repeatability ranged from 1 to 8% for red wine and from 1 to 5% for white wine. The detection and quantification limits were from 0.02 to 0.10 mg/L and from 0.08 to 0.30 mg/L, respectively. The method was successfully applied to detect and quantify biogenic amines in Italian red and white wines from Abruzzo Region. The proposed method is suitable for simultaneous detection and for accurate and precise quantification of eleven biogenic amines in wines.     

Antimicrobial activity of phenolic compounds of wine against Campylobacter jejuni

Campylobacter jejuni is a food pathogen which causes gastrointestinal conditions with an ever-increasing incidence at a global level. The antimicrobial power of wine and its components has been studied. Wines having 11.5% ethanol significantly reduced the viability of C. jejuni when they were diluted to 25% in water. The microbicidal power of red wine was higher than that of white wine. While pH does not seem to affect the viability of this pathogen, different phenolic compounds have an effect on it when tested at concentrations from 0 to 1000 mg/L. Gallic acid and p-hydroxybenzoic acid reduced the viability of C. jejuni at concentrations as low as 1 mg/L, but quercetin and catechin did not even affect it at concentrations of 1000 mg/L. Methyl gallate, epicatechin, synaptic acid, vanillic acid, and caffeic acid were microbicidal at concentrations starting at 10 mg/L. Tryptophol, ferulic acid, and cumaric acid were effective starting at 100 mg/L. According to this, wine constitutes an adverse environment for the survival of this pathogen. Furthermore, it would be interesting to study the possible use of phenolic compounds in wine as an alternative to the use of antimicrobial growth promoters against these bacteria in broilers.     

Antibacterial effect of phenolic compounds from different wines

The antimicrobial properties of pure phenolic compounds and polyphenols of different wines against pathogens were investigated. It was observed that bacterial species exhibited different sensitivities towards the different concentrations of phenolic compounds. Escherichia coli was the most sensitive bacterium and Flavobacterium sp. was resistant against all phenolic compounds tested. All wine samples showed antimicrobial properties and the inhibition increased when the polyphenols concentration of wines increased. Clarified wines were inactive against all bacteria, indicating that polyphenolic compounds present in red wines, are responsible for the antimicrobial effects observed. The different concentrations of polyphenols in wines could have an important impact on consumers with the consequent increase in wine commercialization.     

Use of lysozyme for the prevention and treatment of heterolactic fermentation in the biological aging of sherry wines

Lysozyme treatment has been used in the biological aging of wines to control the development of lactic acid bacteria (LAB) and to mitigate or prevent heterolactic fermentation. To assess this treatment, laboratory and industrial assays were carried out. A lysozyme dose of 6.25 g/h L was found to successfully control LAB populations in wines with high gluconic acid contents. Furthermore, when lysozyme is used in combination with flor velum yeast, volatile acidity content is reduced. Thus, the addition of lysozyme is effective in order to correct and prevent heterolactic fermentation in biological aging wines.     

Aroma compounds as markers of the changes in sherry wines subjected to biological ageing

Capillary-column gas chromatography was used to determine 63 aroma compounds in 9 very pale sherry wines, fino type, subjected to biological ageing under industrial conditions for 1, 3 and 5 years. The contents in aroma compounds were related to the wine ageing time by means of a simple linear regression model. The compounds that exhibited a high correlation coefficient (r>0.90) and simultaneously a high odour impact value (OAV > 5) were additionally subjected to principal component analysis. The first component was found to account for 93.12% of the changes in such compounds during the biological ageing process. The greatest contributions to this component were those from sotolon and 1,1-diethoxyethane, both related to the acetaldehyde produced by the metabolism of flor yeasts, and Z-whisky lactone synthesized from its precursors extracted from the casks wood where the wines were aged. The use of these compounds as markers for biological ageing is advantageous because their changes in concentrations is taken into account as well as their odorant impact.     

Aroma profile of wines from Albillo and Muscat grape varieties at different stages of ripening

Volatile composition of musts and wines from Muscat “a petit grains” and Albillo grape cultivars harvested at different states of ripening, was evaluated. Among the volatile compounds analysed by GC/FID/MS, wines obtained from less ripe grapes displayed higher ester and fatty acid concentrations, but less terpene compounds and benzene derivatives, than wines from grapes with a high degree of maturity. Maturity also greatly influenced wine aroma. In all cases, wines from grapes with higher sugar content were more fruity and less vegetal and floral.     

ELISA and HPLC analysis of ochratoxin A in red wines of Croatia

Ochratoxin A (OTA) contaminates wine all round the world, and its consumption may significantly increase human exposure to this toxin. In this study, enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC) for OTA analysis were tested on must and wine samples collected in Croatia. The results of ELISA and HPLC analysis of OTA in naturally contaminated red wines correlated well (r = 0.821), and the correlation was better at higher OTA concentrations. In contrast to HPLC, ELISA could not detect very low OTA concentrations. OTA concentrations in must (range 19–50 ng/l) were higher than in the wines (range 0–21 ng/l). No must samples showed the presence of Aspergillus carbonarius, which is a common OTA-producing mould affecting grapes.     

Organic wine safety: UPLC-FLD determination of Ochratoxin A in Southern Italy wines from organic farming and winemaking

A fast reversed-phase UPLC method was utilized for Ochratoxin A (OTA) determination in 55 different wine samples (red and white) produced in Southern Italy, during two vintages. All the samples came from vineyards in which the plants were subjected to organic farming and were produced according to an organic winemaking, following strict rules on processing aids. Analytical methods included the clean-up purification by using commercial immunoaffinity columns and an Acquity UPLC^® system equipped with a fluorescent detector; the sensitivity of the analytical method was 0.01 ng mL⁻¹. OTA was detected in all wine samples analyzed and the levels were always below the maximum tolerable EU limit (2 ng mL⁻¹); the red wine samples proved to be more contaminated than the white ones.The occurrence incidence of OTA in wines produced according organic farming and winemaking was comparable with that of commercial wines conventionally produced and wines obtained from organic farming only. The results of this study indicate a low risk of exposure to OTA by consumption of these wines.     

Sequential injection system for the enzymatic determination of ethanol in alcoholic beverages with in-line dilution

A sequential injection system for the enzymatic determination of ethanol in wines with spectrophotometric detection was developed. The determination was based on the enzymatic reaction involving ethanol and NAD⁺ in the presence of alcohol dehydrogenase. A gas-diffusion unit was introduced in the system to perform an in-line dilution. It was possible to operate the system with a reagent consumption of 1.3 mg of NAD⁺, 0.45 U of ADH, and 32 μL of sample, per assay with a determination rate of 21 h⁻¹.The results obtained from the analysis of wine samples were statistically equivalent to those obtained by the reference method, with good repeatability; the relative standard deviation (n = 10) was <1% with a LOQ of 0.3% (v/v).     

Methanol contents of Turkish varietal wines and effect of processing

Methanol levels of Turkish varietal wines obtained from different representative viticultural regions were determined and the effect of maceration time and pectolytic enzyme treatments on the methanol levels of the red wines were investigated. 164 wine samples (60 white, 4 rosé, 100 red) were analysed by gas chromatography–flame ionisation detector (GC–FID). Methanol levels ranged from 30.5 to 121.4 mg/l in white wines, 62.5 to 84.6 mg/l in rosé, and 61.0 to 207.0 mg/l in red wines. The highest level was found in Sultaniye among the white wines, and in Öküzgözü among the red wines. Methanol content of red wines increased with maceration time. Pectolytic enzyme treatments produced significantly higher methanol levels than the control wine. All the results show that methanol levels of Turkish wines are under the maximum acceptable limits of International Office of Vine and Wine (OIV) and do not represent a risk to consumer health.     

High performance liquid chromatography analysis of phenolic substances in Greek wines

Eleven samples of commercially available Greek wines were analyzed in order to determine the phenolic content. For the analysis, reversed phase-high performance liquid chromatography (RP-HPLC) coupled with diode array detection was used. The most abundant phenolic substance detected was (+)-catechin (11.8–40 mg l⁻¹). Red wines contained more phenolic substances than white ones. The effect of aging in oak wood barrels on phenolics was also investigated. Specific types of Greek white wines, “retsina”, were also analyzed. Pitch, which is added to such types of wines, contributes significantly to the increased amount of phenolic compounds present in the wine.     

Effect of SO2 on the formation and evolution of volatile compounds in wines

The aim of this work was to study the influence of SO₂ on the formation and later evolution of volatile compounds in wine bottles made from fermentations of sterilized and inoculated must. For this purpose, Parellada must, sterilized and inoculated with Saccharomyces cerevisiae, was fermented with and without SO₂. Subsequently, the obtained wines were aged in bottle during 6 months at room temperature with and without SO₂. The results show that SO₂ hardly had any effect on the formation of volatile compounds during fermentation. However, the wine stored in bottle with SO₂ showed a higher concentration of volatile compounds, mainly esters and alcohols, than the wine aged in bottle without SO₂.     

Occurrence of ochratoxin A before bottling in DOC and DOCG wines produced in Piedmont (Northern Italy)

Italy is one of the countries where ochratoxin A (OTA) contamination in wine poses more risks. Previous surveys on the occurrence of OTA have poorly considered north Italian wines. In this study, 1206 red and white DOC and DOCG wines produced in Piedmont (Northern Italy) from 2000 to 2007 have been analyzed for OTA level (0.116 μg l⁻¹) and incidence (68.0%). The monitoring – the widest per number of Italian wine samples considered – analyzed the OTA contamination of wines in tanks just before bottling. OTA level and incidence were significantly higher in red (0.121 μg l⁻¹, 69.4%) than in white (0.086 μg l⁻¹, 61.3%) wines. Among the white wines, the incidence was significantly lower in the Moscato wines (7.3%), due to the different wine processing. The differences in the mean OTA level in the three main grapevine varieties of red wines could be related to the harvest period. Among the Nebbiolo appellations, a reduction of the OTA level was noticed with increasing the wood aging period. A significant effect of the vintage year was also registered.     

Fast determination of principal volatile compounds in distilled spirits

A fast determination of principal volatile compounds (acetaldehyde, ethyl acetate, acetal, methanol, butan-2-ol, butan-1-ol and higher alcohols) by direct inject of the spirit drink has been developed. At a total analysis time of 23 min were quantified others 23 additional volatile compounds like ethyl esters, acetates higher alcohols, 1-hexanol, carbonyl compounds and others, responsible for the quality evaluation of the distillate. These compounds are very important for analysis of fermentation conditions, storage techniques and the quality control of the distillation process. The proposed method has been validated with r² values from 0.9988 to 0.9999 with limits of detection varied between 0.003 mg/L for isobutyraldehyde and 0.076 mg/L for diethyl succinate and acceptable reproducibility. The developed method was successfully applied to different samples of grape pomace protected by Specific Denomination “Orujo de Galicia”.     

A new fear in wine: Isolation of Staphylococcus epidermidis histamine producer

Biogenic amines (BAs) are undesirable compounds in all foods and beverages because they may induce food-borne intoxications when consumed at high concentrations. The aim of this study was to identify the organism responsible for the synthesis of histamine in a Tempranillo red wine from Ribera de Duero D.O. (Denomination of origin), Spain. Bacteria present in wines after malolactic fermentation were isolated, identified and typed. Four strains of the species Oenococcus oeni and two strains of Staphylococcus epidermidis were found. None of the O. oeni strains produced histamine, cadaverine or putrescine, but one of the S. epidermidis strains (Pa) was able to produce all three in synthetic medium and grape must, although not in wine. From the data obtained in this work, histamine present in Tempranillo wine B was produced by the S. epidermidis strain Pa. This is the first report in which the presence of S. epidermidis has been reported in wine and whose ability to produce histamine, putrescine and cadaverine has been demonstrated in grape must.