Search results for "winemaking"

Base Wine and Traditional Sparkling Wine Making Using Torulaspora delbrueckii Killer Yeasts

2020

The killer strains of Torulaspora delbrueckii can be used to improve the dominance of this yeast during must fermenta­tion. The present work analyzes its usefulness for traditional spar­kling wine making (base wine and cava). T. delbrueckii killer strain dominated base wine fermentation better than non-killer strains and produced dried wines. The foam ability of T. delbrueckii base wines was very low compa­red to that of Saccharomyces cerevisiae. Significant posi­tive correlations of foam parameters were found with the amounts of C4-C16 ethyl esters and proteins, and negative correlations with some antifoam alcohols. The organoleptic quality of T. delbrueckii base wines was considered inap­…

Biogenic amine determination in wine fermented in oak barrels: Factors affecting formation

2008

Changes in biogenic amines (histamine, putrescine, tyramine and cadaverine) were monitored during the industrial production of Tempranillo and Cabernet Sauvignon wines. The origin of these amines in relation to the presence of different lactic bacteria (indigenous or inoculated) during malolactic fermentation, while aging in oak barrel, and the correlations between amines and their corresponding amino acids were statistically evaluated. In this study we found that there was a greater increase in amines post malic acid depletion than during malolactic fermentation and that more amines were produced in wine of the Tempranillo variety. The total amino acid concentration was 1.6 times greater i…

Principal Parameters of Grape Ripening and Wine Fermentation

2008

Dynamics of Microbial Populations during Fermentation of Wines from the Utiel-Requena Region of Spain

1989

The dynamics of fungi, yeasts, and lactic acid bacteria during fermentation of four musts were studied. Fungi disappeared quickly in the fermenting must. The lactic acid bacteria population diminished during alcoholic fermentation, then they increased and performed malolactic fermentation. Yeasts grew quickly, reaching maximum populations at different times depending on the vinification treatment.

Enological characterization of natural hybrids from Saccharomyces cerevisiae and S. kudriavzevii.

2007

The effect of yeasts on wine flavor response is of primary importance. The genus Saccharomyces, and mainly the species Saccharomyces cerevisiae, is responsible for alcoholic fermentation. Recently, several novel yeast isolates from wines have been described as hybrid yeasts between S. cerevisiae x S. kudriavzevii. We have analyzed their influence on two grape musts (Macabeo and Tempranillo) in fermentations conducted at four different temperatures (14, 18, 22 and 32 degrees C) by studying volatile compound production, sugar assimilation and other characteristics influencing the enological properties of wine caused by the impact of yeast. Hybrid yeasts behave particularly well at 14, 18 and …

Sch 9p kinase and the Gcn4p transcription factor regulate glycerol production during winemaking

2017

Grape juice fermentation is a harsh environment with many stressful conditions, and Saccharomyces cerevisiae adapts its metabolism in response to those environmental challenges. Many nutrient-sensing pathways control this feature. The Tor/Sch9p pathway promotes growth and protein synthesis when nutrients are plenty, while the transcription factor Gcn4p is required for the activation of amino acid biosynthetic pathways. We previously showed that Sch9p impact on longevity depends on the nitrogen/carbon ratio. When nitrogen is limiting, SCH9 deletion shortens chronological life span, which is the case under winemaking conditions. Its deletion also increases glycerol during fermentation, so the…

A Comparative Study of Different Methods of Yeast Strain Characterization

1992

Summary An extensive survey of different methods of yeast strain identification (classical microbiological tests, whole-cell protein electrophoresis, chromosomal patterns, DNA hybridization and mitochondrial DNA restriction analysis) has been carried out in order to differentiate, with industrial purposes, strains present in the Alicante wine ecosystem. Only chromosomal patterns and mitochondrial DNA (mtDNA) restriction analysis show differences between strains. Both techniques are very complex to be used in bio technological industries. For this reason, we have developed a new, simple, unexpensive and rapid method based on mtDNA restriction analysis.

Molecular Characterization of a Chromosomal Rearrangement Involved in the Adaptive Evolution of Yeast Strains

2002

Wine yeast strains show a high level of chromosome length polymorphism. This polymorphism is mainly generated by illegitimate recombination mediated by Ty transposons or subtelomeric repeated sequences. We have found, however, that the SSU1-R allele, which confers sulfite resistance to yeast cells, is the product of a reciprocal translocation between chromosomes VIII and XVI due to unequal crossing-over mediated by microhomology between very short sequences on the 5' upstream regions of the SSU1 and ECM34 genes. We also show that this translocation is only present in wine yeast strains, suggesting that the use for millennia of sulfite as a preservative in wine production could have favored …

Adaptive response to wine selective pressures shapes the genome of a Saccharomyces interspecies hybrid

2021

During industrial processes, yeasts are exposed to harsh conditions, which eventually lead to adaptation of the strains. In the laboratory, it is possible to use experimental evolution to link the evolutionary biology response to these adaptation pressures for the industrial improvement of a specific yeast strain. In this work, we aimed to study the adaptation of a wine industrial yeast in stress conditions of the high ethanol concentrations present in stopped fermentations and secondary fermentations in the processes of champagne production. We used a commercial Saccharomyces cerevisiae × S. uvarum hybrid and assessed its adaptation in a modified synthetic must (M-SM) containing high ethan…

A novel approach for the improvement of stress resistance in wine yeasts

2006

During wine production yeast cells are affected by several stress conditions that could affect their viability and fermentation efficiency. In this work we describe a novel genetic manipulation strategy designed to improve stress resistance in wine yeasts. This strategy involves modifying the expression of the transcription factor MSN2, which plays an important role in yeast stress responses. The promoter in one of the genomic copies of this gene has been replaced by the promoter of the SPI1 gene, encoding for a cell wall protein of unknown function. SPI1 is expressed at late phases of growth and is regulated by Msn2p. This modification allows self-induction of MSN2 expression. MSN2 gene tr…