Masses and widths of the rho(770)

Isospin violation in the $\rho(770)$ mass and width is considered within the $S$ matrix approach using combined fits to the $e^+e^- \to\pi^+\pi^-$ and $\tau^- \to \nu_{\tau}\pi^-\pi^0$ data performed by the ALEPH collaboration. We show that the pole position following from the parameters obtained from the ALEPH fits are not sensitive to the details of the parametrization. In this context, we have found that the pole mass difference and the pole width difference between the charged and neutral $\rho$ are consistent with zero. We show that a one loop calculation including vector, axial vector and pseudo-scalar mesons can satisfactorily describe the observed isospin breaking. We also give an estimate for the mass difference between the neutral and charged states of the $a_1(1260)$.Comment: 8 pages, 1 figur

Flor yeast metabolism in a model system similar to cellar ageing of the French "Vin Jaune": Evolution of some by-products, nitrogen compounds and polysaccharides

French flor-sherry wine "Vin Jaune" (Jura region) made from Savagnin grapes is aged under a film of Saccharomyces cerevisiae flor yeasts for 6 years and three months. During this ageing, velum develops and falls corresponding to yeast multiplication and autolysis, In a model system using glass receptacles ("Fioles de Roux") containing sterilised Savagnin wine inoculated with a pure culture of S. cerevisiae flor yeast, the evolution of velum was studied for 15 weeks. At the same time, nitrogen compounds (amino acids, peptides and proteins) and neutral polysaccharides were quantified in relation to glycerol, volatile acidity and acetaldehyde, Compounds such as glycerol, acetic acid and amino acids including proline are consumed by the flor yeasts whereas other compounds such as peptides and neutral polysaccharides are released. At the same time, yeasts produce other compounds, namely acetaldehyde

Influence of some factors on autolysis of Oenococcus oeni

Oenococcus oeni was able to autolyse after transfer to water at 40 degreesC. Cells harvested in the mid-log phase autolyse more rapidly than in other growth phases. Optimum conditions of pH (broad scale,vith two maxima at 4.0 and 7.0) and temperature (40 degreesC) have also been elucidated. Trypsin and EDTA appeared to enhance cell wall autolysis. The activity of several enzymes, namely an amidase or endopeptidase and a N-acetyl-β-D-glucosaminidase, were shown to be involved in the autolytic process, thereby releasing soluble cell wall fragments and nitrogen compounds

Isolation and characterization of cryotolerant Saccharomyces strains

Cryotolerant Saccharomyces strains were isolated from grape must (Pinot noir) using the enrichment method (CASTELLARI et al. 1992). Eleven cryotolerant strains were collected which all belonged to the S. uvarum species (Melibiose test and karyotype). Fermentations were carried out at 10 and 25 °C, the level of fermentation products was compared with those produced by mesophilic yeasts. Regardless of temperature, cryotolerant yeasts (SY055 and 12233) produced twice as many isobutyl and isoamyl alcohols as mesophilic yeast (FB) and 2-phenethyl alcohol was produced by cryotolerant yeasts at levels 4 times as high as by mesophilic yeasts. The potential of these yeasts for oenological application is discussed

L'elevage sur lie des vins blancs de Bourgogne I. Etude des composés azotés, des acides gras et analyse sensorielle des vins

White wine aging on lees in BourgogneI. Nitrogen compounds, fatty acids and sensory ratingsNous avons comparé l'élevage traditionnel des vins de Bourgogne, en fûts de chêne et sur lie, à l'addition d'autolysats de levures. L'étude porte sur les millésimes 1982 à 1986. Les vins élevés sur lie et ceux additionnés d'autolysats de levures sont plus riches en matières azotées. Nous avons pu mettre en évidence une activité protéolytique dans ces vins e t d ans leurs lies. Les analyses sensorielles, qui n'ont porté pour l'instant que sur des vins jeu nes, font ressortir une préférence pour le vin témoin soutiré. En outre, le jury distingue la plupart des vins en début d'élevage mais ces différences s'atténuent après 2 années de conservation en bouteilles

Characterization of the production regions of Chardonnay wines by analysis of free amino acids

Foe amino acids in 62 Chardonnay varietal wines, originating from Australia, Argentina, South Africa, Switzerland, United States and France (Pays d'Oc, Chablis, Pouilly-Fuisse and Cote de Beaune) were analyzed. They were differentiated according to the region of production using analysis of variance, Flash Table and Canonical Variate Analysis. Wines produced in the Pays d'Oc were identified by the presence of proline, while arginine and alanine served to identify Swiss wines. Chablis wines were characterized by 16 out of 20 major amino acids analyzed. Differences were correlated with climate and therefore with maturity at harvest. However, grape maturity alone did not explain the differences between wines. These differences were also correlated with the latitude of countries. Wines from Australia, Argentina and South Africa were not easily to differentiate. Gate de Beaune wines were distinguished from other Burgundy wines (Chabris, Pouilly-Fuisse), which can be explained by wine ageing on the lees after alcoholic fermentation for 4-6 months

The aroma glycosides composition of Burgundy Pinot noir must

Research Not

L'elevage sur lies des vins blancs de Bourgogne II. Evolution des macromolécules: polysaccharides et protéines

La conservation sur lies des vins blancs de Bourgogne se traduit dans un premier temps par un enrichissement de ceux-ci en composés macromoléculaires précipitables à l'éthanol; puis dans un second temps la teneur en ces composés diminue à la suite d'une hydrolyse des polysaccharides d'origine pariétale.Un étude en milieu modèle permet de préciser que les principaux produits de l'autolyse provenant des parois de levures sont des mannoprotéines qui sont libérées après une hydrolyse enzymatique des glucanes. Les ß(1→3 )-glucanases responsables de cette hydrolyse sont libérées dans le milieu d'autolyse et il en est de même d'une protéase de type A. Ainsi l'hydrolyse des macromolécules se poursuit dans le milieu extracellulaire

Etude de la rétention de composés d'arôme par les bentonites en moût, vin et milieux modèles

Les bentonites étudiées en milieu modèle présentent de grandes différences de capacité de fixation pour les deux composés d'arôme testés: γ-décalactone et β-ionone. L'adsorption de substances d'arôme sur une bentonite semble peu modifiée par la présence d'éthanol à la concentration de 126 ml/1, mais elle est fortement augmentée en présence de glucose et de fructose à la concentration de 100 g/1. Nous avons mis en évidence un effet cumulé de la fixation de la γ-décalactone dû à la bentonite seule et aux protéines piégées par la bentonite. Cependant il n'existe pas de corrélation entre l'efficacite déproteinisante et sa capacité de rétention de substances volatiles.Study of the binding of aroma compounds by bentonites in must, wine and model systemsIn a model system bentonites showed important differences on the binding capacity of the aroma compounds γ-decalactone and beta-ionone. Adsorption of volatile substances was not modified by ethanol at 126 ml/l but was strongly increased by glucose and fructose at a 100 g/l concentration. Additional effects for the binding of γ-decalactone due to bentonite alone and proteins removed by the bentonite were observed. However, no correlation was found between the protein removal efficiency and the binding capacity of aroma compounds

Contribution à l'étude de la dégradation de l'acide L-malique par les bactéries lactiques isolées du vin: Effet stimulant des autolysats de levures

Degradation of L-malic acid by lactic bacteria isolated from wine:Stimulating effect of yeast autolysatesFive yeast autolysates used in the present study showed very different levels of proteolysis. They had a major effect on the growth and the malolactic activity of four strains of lactic acid bacteria isolated from wine (Lactobacillus hilgardii, Leuconostoc mesenteroi'des, Leuconostoc oenos strain 44-40 and Leuconostoc oenos strain B). This effect was always stimulating, but there was considerable interaction between the type of autolysate and the bacterial strain on the one hand and the composition of the culture medium (pH, ethanol) on the other hand