Search results for "wine"
showing 10 items of 1468 documents
Elemental fingerprint of wines from the protected designation of origin Valencia
2009
Abstract Inductively coupled plasma optical emission (ICP-OES), in combination with different chemometric approaches, has been used to verify the origin of different red wine samples from Utiel-Requena, Jumilla, Yecla and Valencia protected designation of origin (PDO). The ability of multivariate analysis methods, such as hierarchical cluster analysis (HCA), principal component analysis (PCA), classification and regression trees (CARTs) and discriminant analysis (DA), to achieve wine classification from their elemental contents has been investigated. The calculations were performed using 38 variables (contents of Al, Ba, Be, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg,…
Wine-making with protection of must against oxidation in a warm, semi-arid terroir
2016
In order to defend varietal aromas from oxidation before alcoholic fermentation, two musts were prepared from white grapes pre-cooled and added with ascorbic acid and solid CO2 (trial ACO2) or SO2 (trial BSO2). Experiments were performed with grapes of a white grape variety indigenous to western Sicily, the wines from which, obtained by vinification of musts protected from oxidation and poor in copper, as previously proven, have aroma descriptors ascribed to passion fruit and grapefruit skin. The smaller content in flavanols in the ACO2 trial, demonstrated that the use of solid CO2, instead of SO2, reduced the extraction of such polyphenols from grape solids. The higher content in hydroxyci…
Studies on Two Exoenzymes Which Lyse Wine-Spoiling Bacteria
2014
Microorganisms play an important role in the conversion of grape juice into wine. Different species of yeast are mainly responsible for the production of ethanol. Lactic acid bacteria also occur regularly in must or wine. They are mostly undesirable due to their capacity to produce wine-spoiling compounds. Especially strains of Lactobacillus brevis are able to produce biogenic amines as well as precursors of ethyl carbamate and different off-flavours (N-heterocycles, volatile phenols). By excessive formation of acetic acid some lactobacilli may even induce slow/stuck grape juice fermentations. In conventional winemaking, additions of sulphite or lysozyme are used to inhibit the growth of sp…
Effect of winemaking process and addition of white grapes on the sensory and physicochemical characteristics of young red wines
2008
Background and Aims: This work studies the effect of winemaking process (carbonic maceration (CM) vs destemming) and the effect of grape variety (100% Tempranillo red grapes vs Tempranillo grapes and Viura white grapes) on sensory and physicochemical characteristics of young red wines from Rioja Alavesa. Methods and Results: Nineteen wines distributed in four groups (the four combinations from the two factors) were collected from 12 wineries. Twenty-four sensory attributes and 15 physicochemical parameters were analysed at four time points through 9 months. Data were analysed by analysis of variance and by canonical variate analysis. CM wines were higher in red berry aroma and flavour, alco…
Effect of micro-oxygenation on the evolution of aromatic compounds in wines: Malolactic fermentation and ageing in wood
2009
Abstract The effect of micro-oxygenation on the aromas of two varietal wines (Tempranillo and Cabernet Sauvignon) when alcoholic fermentation is complete was examined. Several factors, such as whether malolactic fermentation (MLF) took place in barrels or stainless steel vats and ageing time in oak barrels, were taken into account. Major aroma components were studied using GC-FID and minor compounds were studied by GC–MS analysis before and after MLF and after 4 and 8 months of maturation in oak barrels. Sensorial analysis was performed to describe and quantify the different wine notes. Micro-oxygenation affects different compounds but the effect depends to a great extent on the grape varie…
Polyphenoloxidase from Riesling and Dornfelder wine grapes (Vitis vinifera) is a tyrosinase.
2015
Abstract Polyphenoloxidases (PPO) of the type-3 copper protein family are considered to be catecholoxidases catalyzing the oxidation of o-diphenols to their corresponding quinones. PPO from Grenache grapes has recently been reported to display only diphenolase activity. In contrast, we have characterized PPOs from Dornfelder and Riesling grapes which display both monophenolase and diphenolase activity. Ultracentrifugation and size exclusion chromatography indicated that both PPOs occur as monomers with Mr of about 38 kDa. Non-reducing SDS–PAGE shows two bands of about 38 kDa exhibiting strong activity. Remarkably, three bands up to 60 kDa displayed only very weak PPO activity, supporting th…
Orthonasal aroma characteristics of Spanish red wines from different price categories and their relationship to expert quality judgements
2012
Background and Aims: Research aimed to define the olfactory sensory spaces of Spanish red wines from different price segments and to determine relationships between sensory descriptors and quality as evaluated by experts. Methods and Results: A trained panel using a frequency of citation method assessed the orthonasal sensory characteristics of 96 Spanish wines belonging to three price segments (premium; high standard; low standard). Eleven robust sensory terms were built by combining similar terms using statistical criteria. A panel of experts consistently assessed quality. Negative aroma profiles, some of them very skewed, were identified in the different sets with 'animal', 'undergrowth'…
Characterization of wine yeast strains of the Saccharomyces genus on the basis of molecular markers: Relationships between genetic distance and geogr…
1996
Summary We identify and characterize 31 Saccharomyces strains from different wine regions, deposited at the Spanish Type Culture Collection, according to mtDNA restriction patterns and chromosomal profiles. By using this kind of information we analyze the correlation between genetic distances and ecological or geographical factors by means of a cluster analysis, assessed by an analysis of the molecular variance (AMOVA). From these analyses, red wine strains are significantly grouped according to their geographic origin, independently of the wine type and the grapevine cultivar, and white wine strians according to ecological factors (wine type of grapevine cultivars). This study also confirm…
Metabolism of Sugars and Organic Acids by Lactic Acid Bacteria from Wine and Must
2008
Heterofermentative lactic acid bacteria (LAB) which are common in plant associated environments are found also in grape must and wine. In this environment specific strains predominate which are adapted to the low pH and high alcohol contents. Must and wine harbour the strictly heterofermentative Oenococcus oeni, Lactobacillus hilgardii and Lactobacillus brevis, and the facultatively heterofermentative Lactobacillus plantarum and Lactobacillus pentosus (Rodas et al. 2005). In addition homofermentative lactic acid bacteria of the Pediococcus group are able to grow in wine and must, but are normally found at low cell densities. The growth of lactic acid bacteria in wine depends largely on suga…
Saccharomyces cerevisiae-Oenococcus oeni interactions in wine: current knowledge and perspectives.
2003
Winemaking can be summarized as the biotransformation of must into wine, which is performed principally by Saccharomyces cerevisiae strains during the primary or alcoholic fermentation. A secondary fermentation, the so-called malolactic fermentation (MLF) is a biodeacidification that is often encouraged, since it improves wine stability and quality. Malolactic fermentation usually occurs either spontaneously or after inoculation with selected bacteria after alcoholic fermentation. The main organism responsible for MLF, the lactic acid bacterium Oenococcus oeni, develops in physicochemically harsh conditions, which may lead to MLF failure. Furthermore, yeast that ferment must before or toget…