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- Molecular identification and VOMs characterization of Saccharomyces cerevisiae strains isolated from Madeira region winery environmentsPublication . Castillo, Mariangie; Silva, Emanuel da; Câmara, José S.; Khadem, MahnazThe quality and typical characteristic of wines depends, among other factors, on the volatile organic metabolites (VOMs) that are biosynthesized by yeasts, mainly Saccharomyces cerevisiae species. The yeast strain influences the diversity and proportions of the VOMs produced during the fermentation process, as the genetic predisposition of the strains is a by-product of selective adaptation to the ecosystem. The present work reports the characterization of S. cerevisiae strains isolated from grape must, used in the Demarcated Region of Madeira (DRM) for winemaking. Yeast species were identified by amplification and by restriction fragment length polymorphism (RFLP) analysis of the region 5.8S-internal transcribed spacers (PCR-RFLP of 5.8S-ITS) of ribosomal DNA (rDNA). The strains identification was performed by analyzing the RFLP pattern of mitochondrial DNA (RFLP-mtDNA). The representative strains were selected for the characterization of the volatile profile through headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis. A total of 77 VOMs were identified. Higher alcohols, esters, and fatty acids were the major chemical families representing 63%, 16%, and 9%, respectively, in strain A and 54%, 23%, and 15% in strain B. The results indicate the influence of the strain metabolism in the production of VOMs, many of which probably participate in the aroma of the corresponding wines.
- A fast and environment-friendly MEPS PEP /UHPLC-PDA methodology to assess 3-hydroxy-4,5-dimethyl-2(5H)-furanone in fortified winesPublication . Freitas, Jorge; Perestrelo, Rosa; Cassaca, Rubina; Castillo, Mariangie; Santos, Mariana; Pereira, Jorge; Câmara, José S.Sotolon is widely associated with the quality of fortified aged wines, and has also been linked to premature oxidative aging (premox). Here we developed a single, fast and environmental-friendly microextraction by packed sorbent ultra-high pressure liquid chromatography analysis (MEPS/UHPLC-PDA) for sotolon quantification in different wines. The best extraction conditions (loading three times 250μL samples through the MEPSPEP sorbent and elution with 100μL of 50% MeOH) were combined with a fast UHPLC separation (5min separation using acidified 10% MeOH isocratic flow in a CORTECS C18 column) to allow unparalleled minimum sample and solvents volumes usage. The validated methodology showed good linearity (r(2)>0.993) and precision (<5.6%); high recovery (>81%) and detection limits (0.45-2.51μg/L) far below sotolon odor threshold for any type of wine. The methodology was successfully applied to selected white table and Madeira wines, encompassing therefore a wide range of alcohol and sugar contents. Furthermore, as far we may know, this is the first time a single methodology can be used to assess both wine aging or premox according to the type of wine.
- An approach of the Madeira wine chemistryPublication . Perestrelo, Rosa; Luís, Catarina; Gonçalves, Carolina; Castillo, Mariangie; Câmara, José S.Madeira wine is a fortified Portuguese wine, which has a crucial impact on the Madeira Island economy. The particular properties of Madeira wine result from the unique and specific winemaking and ageing processes that promote the occurrence of chemical reactions among acids, sugars, alcohols, and polyphenols, which are important to the extraordinary quality of the wine. These chemical reactions contribute to the appearance of novel compounds and/or the transformation of others, consequently promoting changes in qualitative and quantitative volatile and non-volatile composition. The current review comprises an overview of Madeira wines related to volatile (e.g., terpenes, norisoprenoids, alcohols, esters, fatty acids) and non-volatile composition (e.g., polyphenols, organic acids, amino acids, biogenic amines, and metals). Moreover, types of aroma compounds, the contribution of volatile organic compounds (VOCs) to the overall Madeira wine aroma, the change of their content during the ageing process, as well as the establishment of the potential ageing markers will also be reviewed. The viability of several analytical methods (e.g., gas chromatography-mass spectrometry (GC-MS), two-dimensional gas chromatography and time-of-flight mass spectrometry (GC×GC-ToFMS)) combined with chemometrics tools (e.g., partial least squares regression (PLS-R), partial least squares discriminant analysis (PLS-DA) was investigated to establish potential ageing markers to guarantee the Madeira wine authenticity. Acetals, furanic compounds, and lactones are the chemical families most commonly related with the ageing process.
- Caracterização de estirpes autóctones de Saccharomyces cerevisiae isoladas a partir de ambientes vitivinícolas da Ilha da MadeiraPublication . Castillo, Mariangie Elisa Martinez; Khadem, Mahnaz; Câmara, José de SousaA 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.