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Caracterização de estirpes autóctones de Saccharomyces cerevisiae isoladas a partir de ambientes vitivinícolas da Ilha da Madeira
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Advisor(s)
Abstract(s)
A qualidade e tipicidade dos vinhos depende também dos compostos orgânicos voláteis (VOCs), biossintetizados por Saccharomyces cerevisiae. A estirpe de levedura influencia a diversidade e proporção de VOCs produzidos durante o processo fermentativo, devido à predisposição genética, produto da adaptação seletiva ao ecossistema.
O presente trabalho reporta a caracterização de estirpes de S. cerevisiae isoladas a partir de 100 leveduras provenientes de 10 mostos, obtidos a partir de castas autorizadas/recomendadas para vinificação na Região Demarcada da Madeira (RDM), durante a campanha vitivinícola de 2015.
Primeiramente, a espécie foi identificação através da amplificação e análise do polimorfismo dos fragmentos de restrição (RFLP) da região 5.8S- internal transcribed spacers (PCR-RFLP de 5.8S-ITS) do DNA ribossomal (rDNA). Seguidamente, a identificação das estirpes foi realizada através da análise do padrão RFLP do DNA mitocondrial (RFLP-mtDNA).
Os isolados analisados pertencem a espécie S. cerevisiae e 8 estirpes foram distinguidas. A estirpe B (EB) representou 81 % dos isolados analisados, enquanto que a estirpe A (EA) 11 %. Estas estirpes foram selecionadas para caracterização do perfil volátil com recurso à microextração em fase sólida em modo de espaço de cabeça (HSSPME), seguida da cromatografia em fase gasosa acoplada à espectrometria de massa (GC-MS).
Foram identificados um total de 53 VOCs na EA e 60 na EB. Sendo às famílias químicas maioritárias os álcoois superiores, ésteres e ácidos gordos, representando, respetivamente 63, 16 e 9 % em EA e 54, 23 e 15 % em EB. Dos resultados obtidos pode constata-se a influência do metabolismo da estirpe na produção de VOCs, muitos dos quais, provavelmente, participam no aroma dos vinhos produzidos.
The quality and typical characteristic of wines depend also on the volatile organic compounds (VOCs) that are biosynthesize by Saccharomyces cerevisiae. The strain of the yeast influences the diversity and proportions of VOCs, produced during fermentation process. While the genetic predisposition of the strains is a byproduct of selective adaptation to the ecosystem. The present work reports the characterizations of strains of S. cerevisiae isolated from 100 yeasts from 10 musts obtained from grapes used in winemaking in Demarcated Region of Madeira (RDM), during 2015 campaign. First the yeast species was identified by amplification and analysis of Restriction Fragment Length Polymorphism (RFLP) of the region 5.8 S- Internal Transcribed Spacers (PCR-RFLP of 5.8S-ITS) of ribosomal DNA (rDNA). Then the identification of the strains was performed by analyzing the RFLP pattern of mitochondrial DNA (RFLPmtDNA). The analyzed isolates belonged to the species S. cerevisiae and eight strains were distinguished. The strain B (EB) represented 81% of the isolates analyzed, while the strain A (EA) 11%. These strains were selected for the characterization of the volatile profile through of Headspace Solid-phase Microextraction (HS-SPME) followed by Gas Chromatography coupled to Mass Spectrometry (GC-MS). A total of 53 VOCs in EA and 60 in EB were identified. Higher alcohols, esters and fatty acids were the majority chemical families, representing, respectively 63, 16 and 9% in EA and 54, 23 and 15% in EB. The results obtained can be found the influence of the metabolism of the strain in the production of VOCs, many of which probably participate in the aroma of the wines produced.
The quality and typical characteristic of wines depend also on the volatile organic compounds (VOCs) that are biosynthesize by Saccharomyces cerevisiae. The strain of the yeast influences the diversity and proportions of VOCs, produced during fermentation process. While the genetic predisposition of the strains is a byproduct of selective adaptation to the ecosystem. The present work reports the characterizations of strains of S. cerevisiae isolated from 100 yeasts from 10 musts obtained from grapes used in winemaking in Demarcated Region of Madeira (RDM), during 2015 campaign. First the yeast species was identified by amplification and analysis of Restriction Fragment Length Polymorphism (RFLP) of the region 5.8 S- Internal Transcribed Spacers (PCR-RFLP of 5.8S-ITS) of ribosomal DNA (rDNA). Then the identification of the strains was performed by analyzing the RFLP pattern of mitochondrial DNA (RFLPmtDNA). The analyzed isolates belonged to the species S. cerevisiae and eight strains were distinguished. The strain B (EB) represented 81% of the isolates analyzed, while the strain A (EA) 11%. These strains were selected for the characterization of the volatile profile through of Headspace Solid-phase Microextraction (HS-SPME) followed by Gas Chromatography coupled to Mass Spectrometry (GC-MS). A total of 53 VOCs in EA and 60 in EB were identified. Higher alcohols, esters and fatty acids were the majority chemical families, representing, respectively 63, 16 and 9% in EA and 54, 23 and 15% in EB. The results obtained can be found the influence of the metabolism of the strain in the production of VOCs, many of which probably participate in the aroma of the wines produced.
Description
Keywords
Região Demarcada da Madeira Saccharomyces cerevisiae Estirpes Identificação molecular Compostos orgânicos voláteis Demarcated Region of Madeira Strain Molecular identification Volatile organic compounds Bioquímica Aplicada . Faculdade de Ciências Exatas e da Engenharia