Publicação
Selection of natural Saccharomyces cerevisiae strains for future application in winemaking industry
| Resumo: | The systematic use of starter cultures of commercial Saccharomyces cerevisiae strains in the wine industry has led to the masking of the distinctive peculiarities of wines produced in different geographical regions. In order to overcome this concern, the exploitation of existing microbial diversity in vineyards has been inspecting as an interesting and promising approach. Herein, it is assumed that native populations of S. cerevisiae are better adapted to local conditions, affecting the chemical and sensory profiles of wines in several ways, underlining their terroir. Thus, the main goal of this work was to characterize a subset of 84 autochthonous strains of S. cerevisiae yeast isolated from grape must and wines from the Douro Demarcated Region. To accomplish it, a genotypic characterization was performed after interdelta PCR to the DNA extracted from isolates. However, no significant associations were found between genomic profiles and geographical origin. It was also performed a set of tests, established by the OIV, which allowed to obtain a phenotypic characterization and consequently evaluate its oenological potentials. The isolates were evaluated regarding their resistance to various stresses (ethanol, SO2, temperature, chitosan, copper, H2O2, acetic acid, osmotic stress and nutrient limitation), aroma-related activities (TFL and cerulenin resistance and activities of β-glucosidase, β-lyase and sulphite reductase), as well as other relevant technological properties such as proteolytic activity. The response of autochthonous S. cerevisiae yeasts to the different oenological parameters evaluated was highly dependent on the strain. Growth capacity at different concentrations of ethanol and acetic acid, osmotic stress, nutrient limitation, sulphite reductase and β-glycosidase activity were the tests with highest discriminative power. Some of the isolates that demonstrated oenological potential were selected and subsequently tested as starter cultures in fermentations of red and white musts, allowing to evaluate the fermentative performance and the production of volatile and non-volatile compounds. The fermentation at laboratory scale confirmed that some of the selected indigenous strains possesses oenological properties similar to the commercial strains used as control. The results obtained regarding the fermentation performance and the production of volatile and non-volatile compounds prompt the future application of two natural isolates as starters in wine fermentations. |
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| Autores principais: | Fonseca, Francisco José Monteiro |
| Assunto: | Saccharomyces cerevisiae indigenous yeasts |
| Ano: | 2020 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade de Trás-os-Montes e Alto Douro |
| Idioma: | inglês |
| Origem: | Repositório da UTAD |
| Resumo: | The systematic use of starter cultures of commercial Saccharomyces cerevisiae strains in the wine industry has led to the masking of the distinctive peculiarities of wines produced in different geographical regions. In order to overcome this concern, the exploitation of existing microbial diversity in vineyards has been inspecting as an interesting and promising approach. Herein, it is assumed that native populations of S. cerevisiae are better adapted to local conditions, affecting the chemical and sensory profiles of wines in several ways, underlining their terroir. Thus, the main goal of this work was to characterize a subset of 84 autochthonous strains of S. cerevisiae yeast isolated from grape must and wines from the Douro Demarcated Region. To accomplish it, a genotypic characterization was performed after interdelta PCR to the DNA extracted from isolates. However, no significant associations were found between genomic profiles and geographical origin. It was also performed a set of tests, established by the OIV, which allowed to obtain a phenotypic characterization and consequently evaluate its oenological potentials. The isolates were evaluated regarding their resistance to various stresses (ethanol, SO2, temperature, chitosan, copper, H2O2, acetic acid, osmotic stress and nutrient limitation), aroma-related activities (TFL and cerulenin resistance and activities of β-glucosidase, β-lyase and sulphite reductase), as well as other relevant technological properties such as proteolytic activity. The response of autochthonous S. cerevisiae yeasts to the different oenological parameters evaluated was highly dependent on the strain. Growth capacity at different concentrations of ethanol and acetic acid, osmotic stress, nutrient limitation, sulphite reductase and β-glycosidase activity were the tests with highest discriminative power. Some of the isolates that demonstrated oenological potential were selected and subsequently tested as starter cultures in fermentations of red and white musts, allowing to evaluate the fermentative performance and the production of volatile and non-volatile compounds. The fermentation at laboratory scale confirmed that some of the selected indigenous strains possesses oenological properties similar to the commercial strains used as control. The results obtained regarding the fermentation performance and the production of volatile and non-volatile compounds prompt the future application of two natural isolates as starters in wine fermentations. |
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