Search results for " WINE"
showing 10 items of 335 documents
Fermentative stress adaptation of hybrids within the Saccharomyces sensu stricto complex.
2008
Along the fermentation process yeasts are affected by a succession of stress conditions that affect their viability and fermentation efficiency. Among the stress conditions the most relevant are high sugar concentration and low pH in musts, temperature and, as fermentation progresses, ethanol accumulation. Nowadays, due to the demanding nature of modern winemaking practices and sophisticated wine markets, there is an ever-growing search for particular wine yeast strains possessing a wide range of optimized, improved or novel enological characteristics. Traditionally, the species S. cerevisiae and S. bayanus within the Saccharomyces sensu stricto species are considered some of the most impor…
Improvement of volatile composition of wines by controlled addition of malolactic bacteria
1999
The effect of malolactic fermentation (MLF) on the volatile composition of red wines was studied by inoculation with selected lactic acid bacteria. Four wines were inoculated with different Oenococcus oeni (syn. Leuconostoc oenos) strains, the major malolactic species found in wines, and one was inoculated with a Lactobacillus sp. strain. A non inoculated wine was also analyzed to act as a control. Malolactic fermentation and evolution of non volatile compounds were followed by HPLC and after the depletion of the malic acid present in wine the volatile compounds were extracted and analyzed by gas chromatography with flame ionization and mass spectrometry. Wines which had undergone the MLF s…
Identification of a yeast strain as a potential stuck wine fermentation restarter: a kinetic characterization
2013
Restarter yeast strains are used to consume residual sugar (mainly fructose) in stuck wine fermentations. Forty-three yeast strains were evaluated initially. Strain ITD-00068 showed the highest values for the maximum growth rate, maximum fructose consumption rate, and maximum ethanol production rate (0.143, 0.268, and 0.231 h−1, respectively). Therefore, it was selected for further molecular and kinetic analyses. RFLP analysis identified this isolate as Saccharomyces cerevisiae. Strain ITD-00068 consumed 100% and 36% of the fructose present (at 20°C and 30°C, respectively), when cultured in medium with 12% (v/v) ethanol. The fructose consumption rate was reduced by 97% at 30°C, when ethanol…
Screening of Hanseniaspora Strains for the Production of Enzymes with Potential Interest for Winemaking
2015
Some non-Saccharomyces yeasts, including Hanseniaspora, participate in the first stages of wine fermentation. Besides their importance in the wine production process some of these yeasts have been described to be potential producers of hydrolytic enzymes to industrial level. In this work, we pretend to evaluate the technological abilities of the Hanseniaspora strains deposited in the Spanish Type Culture Collection (CECT). First of all, we considered verification of the correct identification of the strains using several miniaturized biochemical systems and molecular techniques (PCR, RFLP and sequencing of the ribosomal D1/D2 region). The results allowed us to verify the correct adscription…
Stress response and expression patterns in wine fermentations of yeast genes induced at the diauxic shift
2000
During wine fermentation yeasts quickly reach a stationary phase, where cells are metabolically active by consuming sugars present in grape must. It is, consequently, of great interest at this stage to identify suitable gene promoters that may be used to induce the expression of genes with enological applications. With this aim, we have studied a group of genes showing an induction peak at the diauxic shift, and possessing stress response elements (STRE) at their promoters. We have determined their induction levels under individualized stress conditions, such as carbon source starvation or high salt concentrations. In all the cases studied, the activation and/or basal transcription are depe…
A comparative study of the wine fermentation performance of Saccharomyces paradoxus under different nitrogen concentrations and glucose/fructose rati…
2010
8 pages, 1 figure, 4 tables.-- Online version published: May 2009.-- The definitive version is available at www3.interscience.wiley.com
Selection and molecular characterization of wine yeasts isolated from the ‘El Penedès’ area (Spain)
2000
Abstract A study of the microbiota present during the wine fermentation of five grape varieties from the ‘El Penedes’ area (Spain) was carried out to select autochthonous yeast strains for industrial wine production. In this study we identified members of the genera Candida, Dekkera, Hanseniaspora, Kluyveromyces, Torulaspora, Zygosaccharomyces and Saccharomyces in wine fermentation microbiota. Strains of Saccharomyces cerevisiae, as responsible agents of the alcoholic fermentation, were considered for a selection protocol. In this work we applied different enological criteria for selection, but previously we have characterized and differentiated Saccharomyces isolates by molecular methods t…
Amino acids and volatile compounds in wines from Cabernet Sauvignon and Tempranillo varieties subjected to malolactic fermentation in barrels
2012
The aim of the present paper is to compare the behaviour of industrial lactic bacteria and indigenous bacteria of the cellar when malolactic fermentation was carried out in barrels. The effects of these bacteria on the concentration of metabolised amino acids during malolactic fermentation and on the composition of volatile compounds both before and after malolactic fermentation are studied. The experiment was performed with wines of the Tempranillo and Cabernet Sauvignon varieties. An analysis has been made of the easily extractable volatile compounds of the wood and the compounds from the grapes, and the action of the yeasts during the alcoholic fermentation. Acetoin and diacetyl decreas…
Aroma compounds in wine as influenced by apiculate yeasts
1996
Aroma compounds of wines resulting from fermentation of sterile grape musts from Monastrell variety inoculated with pure and mixed cultures of apiculate and Saccharomyces yeasts, were isolated and analyzed by gas chromatography with flame ionization and mass spectrometry. Samples fermented with mixed cultures produced a higher concentration of selected compounds and higher total amounts of alcohols and acids, in contrast with wines produced with pure cultures of Saccharomyces spp. Apiculate yeasts are important in the chemical composition and quality of wine.
Different Behaviour of Plasma Antioxidant Status after Red Wine Consumption in Subjects of the Same Sex: A Preliminary Report
2012
<p>Several studies report that the plasma antioxidant capacity (PAC) increases after a single ingestion of red wine. However, data on the different behaviour of PAC after food intake in subjects of the same sex are still lacking. On the basis of these observations some investigations were undertaken in order to evaluate the effects of red wine intake on PAC in a homogeneous groups of healthy female volunteers (n=18). Additionally, the possible correlation between increase of PAC values and increase in uric acid levels was also assessed. PAC and uric acid concentrations were determined before wine intake and 50, 120 and 240 minutes thereafter. The results obtained following these studi…