Sherry Wines Research Articles

Changes in Color and Odorant Compounds during Oxidative Aging of Pedro Ximenez Sweet Wines

Pedro Ximenez sweet wines obtained following the typical criaderas and solera method for sherry wines and subjected to oxidative aging for 0, 1.3, 4.2, 7.0, or 11.5 years were studied in terms of color and aroma fraction by using the CIELab method and gas chromatography, respectively. The parameters defining the CIELab color space (a*, b*, and L*) were subjected to a multiple-range test (p<0.05) that allowed discrimination of the five wine aging levels studied into five uniform groups according to aging time. The aroma fraction was found to include 15 active odorant compounds with OAV > 1 that enriched the wines with fruity, fatty, floral, and balsamic notes during the aging process. The changes in color parameters and active odorants were not linearly related to aging time, being especially marked during the first 1.3 years and then less substantial up to the 7 years, the oldest wines exhibiting sensorial properties markedly departing from all others. For the wines aged over 1.3 years (minimum aging), 2,3-butanedione, linalool, and decanal can be used as reliable fingerprints of the older wines' quality.

Metallic profiles of Sherry wines using inductively coupled plasma atomic emission spectrometry methods (ICP-AES)

Douze elements metalliques (aluminium, calcium, cuivre, fer, magnesium, manganese, potassium, sodium, zinc, strontium, baryum et phosphore) ont ete determines par plasma a couplage inductif couple a la spectrometrie d'emission atomique (ICP-AES), dans cent echantillons provenant de l'Appellation Jerez-Xeres-Sherry et Manzanilla-Sanlucar de Barrameda. Ces echantillons sont traites par mineralisation humide avec H 2 O 2 /HNO 3 et chauffage. Les resultats montrent la normalite des distributions des elements metalliques. L'application de la statistique non parametrique (median, intervalle interquantil) a ete etudie. Les valeurs moyennes (medians) pour ces elements trouvees dans les echantillons sont les suivants, exprimees en mg/L : 1.66 (Al) ; 0.03 (Ba) ; 68.46 (Ca) ; 0.14 (Cu) ; 1.83 (Fe) ; 465.58 (K) ; 58.34 (Mg) ; 0.57 (Mn) ; 29.92 (Na) ; 61.27 (P) ; 0.93 (Sr) ; 0.47 (Zn). La correlation parmi les divers elements metalliques est donnee en utilisant la methode non parametrique de Spearman. La teneur des metaux dans les vins analyse est plus elevee que pour les brandies de xeres, excepte pour le Cu et le Na. En raison de cette etude des profils metalliques des vins de xeres, et en raison de sa consommation, nous pouvons proposer qu'ils apportent a minimum contribution aux limites de securite (par semaine) de ces elements pour les buveurs normaux, entre 0,2 % pour le Al et 10,2 % pour le Mg.

An Assessment of the Role Played by Some Oxidation-Related Aldehydes in Wine Aroma

The levels of important oxidation-related aldehydes, such as methional, phenylacetaldehyde, (E)-2-hexenal, (E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal, methylpropanal, 2-methylbutanal, and 3-methylbutanal, were determined in 41 different wines belonging to different types (young whites and reds, natural sparkling wines, oxidized young whites and reds, Sherry, aged red wines, Port wines). Except (E)-2-hexenal and (E)-2-heptenal, all of them could be found at levels above threshold. Different compositional patterns were identified: Sherry wines have large amounts of branched aldehydes but not of (E)-2-alkenals, wines exposed to oxygen can have large amounts of (E)-2-alkenals but not of branched aldehydes, while aged wine and Port have relatively large amounts of both classes of compounds. Different sensory tests confirmed the active sensory role of these compounds and revealed the existence of interactions (additive or synergic) between them and with other wine volatiles. (E)-2-Alkenals are related to flavor deterioration, while branched aldehydes enhance dried fruit notes and mask the negative role of (E)-2-alkenals.

Influence of nitrogen on the biological aging of sherry wine

AbstractNitrogen compounds are essential to the growth and metabolism of yeasts. The uptake and metabolism of nitrogen compounds by Saccharomyces cerevisiae depend not only on the strain and its physiological condition, but also on the chemical and physical properties of its environment. The effect of the addition of different amino acids (L‐proline, L‐threonine, L‐arginine, L‐glutamic acid, L‐leucine and L‐valine) to nitrogen‐depleted natural or nitrogen‐free synthetic wine on the cell growth, flor velum formation and sherry wine compound production was investigated under controlled biological aging by S. cerevisiae var. capensis strain G1 a typical flor yeast. The formation of flor velum was dependent on particular amino acid, oxygen availability and the composition of wine. Consumption of glycerol was related with the cell growth; in contrast, acetaldehyde tended to be released. Amino acid supplementation resulted in the release to wine of amino acids, esters and higher alcohols. The amino acid which was released in nearly all cases was L‐leucine. Addition of L‐glutamic acid resulted in the release mainly of ethyl acetate, in the case of L‐leucine isoamyl alcohols were released, and for L‐valine isobutanol. In the three cases, 1,1‐diethoxyethane was released in large quantities. The findings might indicate that the regulation of metabolism succeeds in the most efficient balancing of the redox potential. Copyright © 2006 Society of Chemical Industry

Biological aging of sherry wines under periodic and controlled microaerations with Saccharomyces cerevisiae var. capensis: Effect on odorant series

Wine aged for 2 years in cellar conditions and a batch of non aged wine were subjected to biological aging with S. cerevisiae var. capensis under controlled microaeration. Another batch of the non aged wine and 4 year aged wine in cellar conditions were used as control and named initial and final control wines, respectively. Thirty-five aroma compounds were quantified by GC–MS, and grouped in nine odorants series to compare the microaerated wines with the control wines. Fruity, balsamic, floral, herbaceous, fatty and roasty series increases their values, while solvent and phenolic diminishes by the effect of yeast metabolism. Roasty and spicy series show the higher values in wines previously aged in cellar conditions for 2 and 4 years probably due to the contact of the wine with the wood. The roasty series is dependent of compounds such as 2,3-butanedione, 2,3-pentanodione, 4-ethylguaiacol and some lactones, whereas the spicy series is only dependent on 4-ethylguaiacol. The similarity obtained for some odorant series in wines aged under controlled conditions and wines aged for 4 years in cellar, suggest that the biological aging time can be shortened using a first step for wine aging in stainless-steel under controlled and periodic microaerations and a second step in an oak cask under cellar conditions.

Higher alcohols concentration and its relation with the biological aging evolution

The production of 1-propanol, isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 2-phenylethanol by two flor yeast strains during accelerated biological aging of sherry wines with different aging time has been evaluated. The S. cerevisiae G1 strain has shown a higher production of higher alcohols than the S. bayanus F12 strain highlighting the 1-propanol production in the youngest wine. Differences between the two studied yeasts decreased in relation with the aging time of the initial wine used. The multiple regression analysis carried out to relate the higher alcohols concentration and the values obtained from an aging equation showed R-squared values ranging from 81.1 to 96.5%. The higher alcohols that best described such relation were 1-propanol, isobutanol and 3-methyl-1-butanol.

Determination of the phenolic composition of sherry and table white wines by liquid chromatography and their relation with antioxidant activity

The purpose of this work is to study possible relationships between the antioxidant activity (AA) of 13 table white and 9 sherry wines and their phenolic composition. Twenty phenolic compounds were determined by liquid chromathography (LC). AA has been determined by different methods, including 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Oxygen Radical Absorbance Capacity (ORAC). The AA of pure phenolic standard compounds has also been measured. Statistical study has been performed using multiple regression analysis and artificial neural networks to ascertain if a specific phenolic composition accounts for a higher AA. Certain phenolic compounds exhibit a high linear correlation with the overall AA of wines. For example, gallic acid, glucoside of cutaric acid and tyrosol as determined by the ORAC method. If we study AA values obtained by ABTS and DPPH methods, a good correlation is obtained with (−)-epigallocatechin gallate and ethyl caffeate. The contribution of each phenolic compound to the AA was also examined. Gallic acid, protocatechuic acid, caffeic acid and tyrosol are the main contributors to the ORAC value. If we use ABTS and DPPH methods, the main contributors are gallic, caffeic and caftaric acids and (−)-epigallocatechin gallate. An equation calculated by Multiple Regression Analysis correlates ( r = 0.9028) ORAC values of wines with concentration of certain phenolic compounds (gallic acid, protocatechuic acid, tyrosol, caffeic acid, (−)-epigallocatechin gallate, coumaric acid and 2-furaldehyde).

Retention of Browning Compounds by Yeasts Involved in the Winemaking of Sherry Type Wines

Wine model solutions were used to study the ability of dehydrated yeasts to retain the brown products formed in the reaction between (+)-catechin and acetaldehyde. Saccharomyces cerevisiae races capensis and bayanus, two typical flor yeasts involved in the biological aging of sherry wines, had a higher capacity to retain coloured compounds than S. cerevisiae fermentative yeast. Of the flor yeasts, capensis exhibited a higher colour reduction capacity than bayanus. Such differences may account for the different rate at which browning compounds are removed at different times of year during the biological aging of wines.

Changes in the polyphenolic and volatile content of “Fino” Sherry wine exposed to high temperature and ultraviolet and visible radiation

Experiments of accelerated oxidation of “Fino” Sherry wines have been conducted at different temperatures (25 and 45 °C) and under the influence of UV–Vis radiation (a xenon lamp of 1500 W). Two types of glass bottle were employed: topaz bottles (with low values of transmittance in the UV–Vis range) and transparent bottles. To identify significant differences between the wine before and after being subjected to the influence of these factors, the values of absorbance at 420 nm and the concentrations of various polyphenolic and volatile compounds were submitted to a multivariate variance analysis. The three factors “temperature”, “radiation”, and “time” had a statistically significant effect on the values of absorbance at 420 nm and on the concentration of most of the polyphenolic and volatile compounds, while the “bottle” factor was only significant for polyphenol content. All the wines showed losses in several polyphenolic compounds, which were more severe for the wines bottled in transparent glass. The combined application of high temperature and UV–Vis radiation provoked significant decreases in most of the volatile compounds monitored.

Effects of Grape Destemming on the Polyphenolic and Volatile Content of Fino Sherry Wine during Alcoholic Fermentation

This study has been conducted to explore the influence of different degrees of destemming on the polyphenolic and volatile content of wines from the Palomino finogrape variety. Wines obtained from destemmed grape did not present reduced polyphenolic content. No relationship was observed between degrees of destemming and changes in the polyphenolic content. Destemming prior to pressing did not modify the production of volatile compounds during fermentation and wines with similar organoleptic characteristics to those without destemming were obtained.

Biological Aging of Sherry Wines Using Pure Cultures of Two Flor Yeast Strains under Controlled Microaeration

Sherry wines obtained after biological aging for an average of 0, 2, and 4 years were inoculated separately with the flor yeast strains Saccharomyces cerevisiae var. capensis and Saccharomyces bayanus and subjected to short, periodic microaeration to a dissolved oxygen concentration of 4 mg L(-1) after formation of the yeast film. A principal component analysis with the acetaldehyde, ethanol, volatile acidity, and glycerol concentrations obtained was performed. The first principal component was found to account for 49.5% of the overall variance and to be defined mainly by glycerol and ethanol. The second component accounted for 38.8% of the variance and was defined by volatile acidity and acetaldehyde. The conditions used in the tests allowed the biological aging of the wines to be substantially shortened. Thus, 42 days after flor-film formation by S. cerevisiae var. capensis, 0- and 2-year-old wines exhibited parameter values similar to those obtained for the wine aged for 4 years. The wines inoculated with S. bayanus exhibited high acetaldehyde concentrations and ethanol levels above 15% (v/v)-sherry wines with alcohol concentrations below 14.5% are undesirable-, so one need not exclude the sequential or simultaneous inoculation of S. bayanus together with S. cerevisiae var. capensis in order to improve the biological aging process.

Determination of the Age of Sherry Wines by Regression Techniques Using Routine Parameters and Phenolic and Volatile Compounds

This paper describes a study of the possibility of obtaining regression models by means of partial least squares (PLS) and multiple linear regression (MLR) that would enable us to correlate a series of parameters, such as the concentration of short-chain organic acids, higher alcohols, and phenolic compounds with the age of vintage Sherry wines or "anadas". The aim of this study is to characterize how these parameters evolve with aging. If this could be done, it would then be possible to guarantee the age of such wines using objective variables. A PLS regression model was established that allows the age to be predicted with a mean deviation of 1.6 years with respect to the age of the wines. In the case of the MLR, a model with 6 variables was obtained that gives a mean deviation of 3.3 years in the predictions.

Aromatic series in sherry wines with gluconic acid subjected to different biological aging conditions by Saccharomyces cerevisiae var. capensis

Wines from healthy grapes supplemented with gluconic acid were subjected to biological aging under two experimental conditions. The first one was carried out under flor yeast velum as in the traditional biological aging and the second one under submerged cultures. The highest gluconic acid consumption was observed in aged wines in submerged cultures. Nine aromatic series were obtained by grouping the 48 volatile compounds quantified in wines. The aroma profile based on the aromatic series allows comparison of the changes due to the gluconic acid consumption and the changes due to the different aging conditions assayed. Only the herbaceous and fatty series showed diminished values of consequence of gluconic acid consumption. The fatty, herbaceous and roasty series show highest values, whereas the fruity, floral, solvent and medicinal series reached lower values in the submerged cultures assay. The application of the assay conditions to winemaking can reduce the gluconic acid concentration in wines obtained from rotten grapes.

Near Infrared Spectroscopy and Pattern Recognition Methods Applied to the Classification of Vinegar According to Raw Material and Elaboration Process

Near infrared (NIR) spectroscopy is used to classify vinegar samples according to the raw material of origin (white, red, aged and balsamic wine, malt, cider and molasses) and elaboration processes such as ageing in wood or must addition. Balsamic vinegar from Modena and Sherry wine vinegar are also included in the study; these vinegars are sometimes aged using a battery of barrels or “ soleras and criaderas” system that give the final product a special character. The differences between these samples and the other vinegar samples are also described in this study. Multivariate analysis techniques, cluster analysis, minimum-spanning tree, potential functions and discrimination via regression methods, apart from soft independent modelling of class analogy (SIMCA) and unequal class models (UNEQ) class-modelling techniques, were used to extract the information from the NIR spectral variables. These methods enable the development of models to classify the different groups of vinegar samples and provide accurate information on the specific characteristics of the vinegars related to the elaboration process of the several raw materials. A high percentage of correct classifications were obtained for wine, cider, malt, Balsamic and Sherry vinegars, ranging from 85.7 to 100%. Molasses vinegar was grouped with non-aged wine or cider samples depending on its acetic grade.

Lipid composition of lees from Sherry wine.

In this paper, we describe the study and characterization of the lipids from lees of Sherry wine, one of the main byproducts from the wine-making industry in the Jerez/Xeres/Sherry denomination of the origin zone in Jerez de la Frontera, Spain. The lipid content, extractability, classification, fatty acid composition, and its main chemical characteristics have been determined in order to evaluate their potential use as a food or food additive.

Effect of Schizosaccharomyces pombe on aromatic compounds in dry sherry wines containing high levels of gluconic acid.

Volatile compounds have been determined in control dry sherry wines and those supplemented with gluconic acid, which were inoculated with the Schizosaccharomyces pombe 1379 (ATCC 26760) yeast strain. These compounds were grouped, according to volatiles exhibiting the identical odor quality, into nine groups of the same odor character (aromatic series) as a way of establishing the aroma profile for the studied wines. Control and supplemented wines showed changes in the balsamic, spicy, roasty, and fruity aromatic series, and tasters judged the aroma as typical of wines subjected to biological aging. This fission yeast may be used as a treatment to reduce gluconic acid contents in wines obtained from rotten grapes, making feasible the incorporation of these wines into the biological aging process. In addition, this procedure may also help to accelerate the traditional biological aging in sherry winemaking due to the contribution of some specific compounds by S. pombe to the wine.

Release of macromolecules by Saccharomyces cerevisiae during ageing of French flor sherry wine “Vin jaune”

The French flor sherry wine “Vin jaune” spends 6 years and 3 months in the same barrel under a yeast velum. Because of temperature variations in the cellars, this velum sinks partially into the wine and a deposit of dead yeasts cells accumulates in the bottom of the barrels, favouring the formation of new velum. Growth and autolysis occur simultaneously. This study investigated the evolution of macromolecules released by yeasts during the ageing of “Vin jaune” in a model system closely simulating winemaking. It was observed that the release of macromolecules during the formation of the velums by living yeasts was low but greatly increased when the velums fell and yeast viability decreased. The release of macromolecules was then due to the autolysis of dead cells. Analysis of macromolecules during ageing revealed that they contained 73.3–78.5% neutral sugars and 6–7% proteins according to the ageing stage. Their amino acid composition did not change during ageing. A high content of serine and threonine commonly involved in O-glycosidic linkages present in yeast mannoproteins was observed. Throughout ageing, the mannose and glucose contents of macromolecules increased but the ratio of polymeric mannose to glucose decreased. Size exclusion chromatography showed that mannoproteins released in wine were partially hydrolysed by yeast β-1,3-glucanases freed in wine.

Comparative analysis of volatile compounds of ?fino? sherry wine by rotatory and continuous liquid?liquid extraction and solid-phase microextraction in conjunction with gas chromatography-mass spectrometry

Different headspace solid-phase microextraction (HS-SPME) methods have been selected and applied to the analysis of volatile compounds in ‘fino’ sherry wine by gas chromatography-mass spectrometry. A method based on rotary and continuous liquid–liquid extraction (LLE) for analysis of these same compounds has been optimised. The best conditions to extract this type of compounds using SPME and LLE were determined and both methods were validated. Both methodologies show adequate detection and quantitation limits, and linear ranges for correctly analysing these compounds. The recoveries obtained were close to 100%, with good repeatability values. The analytical and procedural advantages and disadvantages of these two methods have been compared. In general, SPME presented higher sensitivities. Both analytical methods were used to analyse five samples of ‘fino’ sherry wine supplied by different producers. No significant differences were found between the techniques at a significance level of 5%. The regression coefficients (r2) for analysis using LLE and SPME exceeded 0.94 for all compounds. The LLE procedure is a method with high repeatability and has the possibility of simultaneous extraction of several samples (up to 12), however the SPME technique is a solvent-free method presenting major advantages, such as small sample volume and higher sensitivity and simplicity.

The antioxidant activity of wines determined by the ABTS [rad]+ method: influence of sample dilution and time

The free radical scavenging activity of 42 Spanish commercial wines was determined using the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS +). The ABTS + radical was generated enzymatically using a horseradish peroxidase and hydrogen peroxide. The presence of wine phenolic compounds caused the absorbance of the radical to decay at 414 nm. The measurement conditions were optimised. The total phenolic content of wines ranged from 1262 to 2389 mg l −1 for red wines and 70 to 407 mg l −1 for white wines, expressed as gallic acid equivalents. The phenolic content of Sherry wines was similar to that of white wines. Optimum dilutions for white and Sherry wines were set up as a function of their total phenolic content (for total phenol index, TPI<300 mg gallic acid per liter, dilution 2.5:10 to 5:10; for TPI>300 mg gallic acid per liter, dilution 1:10 to 3:10). Red wines absorb at the wavelength of measurement and dilutions between 0.35:10 and 0.1:10 are advisable. Reaction kinetics were also monitored and the antioxidant activity, expressed as Trolox Equivalent Antioxidant Capacity (TEAC), was determined at 2 and 15 min of reaction. The mean values for TEAC 2 min were 5.01±1.40 mM for red wines, 0.46±0.32 mM for white wines and 0.26±0.19 mM for Sherry wines. At 15 min, mean values were 6.93±2.41 mM for red wines, 0.67±0.47 mM for white wines and 0.26±0.19 mM for Sherry wines. The correlation coefficients were better at 2 min ( r=0.9012) than at 15 min ( r=0.8462) when compared with TPI. Hence, TEAC 2 min seems to be a more appropriate measure.

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.