In recent years, wine market is undergoing a change due to the ever-growing request to improve the sensory features and nutritional properties of the final product. Most wine production is based on the use of starter cultures consisting of selected strains of Saccharomyces cerevisiae, able to ensure quick and safe fermentations. However, the reduced number of really different starters can led to a wine standardization resulting in flattening of taste. In order to gain innovative characteristics of quality, the research is looking for new yeasts to be employed as starters (Ciani et al., 2010). The present work had the double aim to investigate the yeast biodiversity in Georgia, an ancient and geographically isolated wine region where the use of starter cultures is still not spread, and to select non-conventional yeast species as new starter cultures. The isolation of yeasts was carried out by sampling grapes, musts and wines in six Georgian areas. One hundred and seventy six isolates were identified by ITS RFLP as described by Vigentini et al. (2009) and partial sequencing of D1/D2 domain 26S rDNA. In total, 14 different species were identified: S. cerevisiae (36.4%), Hanseniaspora gulliermondi and Metshnikowia pulcherrima (about 20%), Cryptococcus flavescensis (8%), Cryptococcus carnescens and Torulaspora delbrueckii (about 3%), Candida intermedia, Pichia guilliermondi and Pichia kluyveri (about 2%), Candida gotoi, Issatchenkia terricola, Cystofilobasidium infirmominiatum, Kluyveromyces marxianus and Hanseniaspora osmophila (≤ 1%). The screening involved the analysis of technological traits (alcohol and SO2 tolerance, acetic acid, glycerol and H2S production). One K. marxianus and one T. delbrueckii strains with interesting features, were inoculated in two different musts to investigate the oenological potential. Significant differences in the aromatic profiles were observed by GC/MS analysis between the strains and, in particular, they both produced compounds such as 3-methyl-1- butanol, 2-phenylethanol, ethyl hexanoate, ethyl octanoate, ethyl decanoate and ethyl 9-decenoate in amounts higher than the commercial S. cerevisiae cultures, used as reference. Micro-vinification experiments revealed that both strains are viable up to about 13% (v/v) alcohol in co-presence with the S. cerevisiae strains naturally present in musts. In conclusion, these strains proved to be promising for future application as wine non-conventional starter cultures.
Survey on yeast biodiversity in Georgian vineyards: a still pristine environment for the selection of non S. cerevisiae wine strains / I. Vigentini, D. Maghradze, M. Rossoni, S. Capponi, C. Picozzi, O. Failla, R. Foschino. ((Intervento presentato al 3. convegno Convegno nazionale Società Italiana di Microbiologia Agraria, Alimentare e Ambientale tenutosi a Bari nel 2012.
|Titolo:||Survey on yeast biodiversity in Georgian vineyards: a still pristine environment for the selection of non S. cerevisiae wine strains|
VIGENTINI, ILEANA (Primo)
FAILLA, OSVALDO (Penultimo)
FOSCHINO, ROBERTO CARMINE (Corresponding)
|Data di pubblicazione:||28-giu-2012|
|Settore Scientifico Disciplinare:||Settore AGR/16 - Microbiologia Agraria|
Settore AGR/03 - Arboricoltura Generale e Coltivazioni Arboree
|Citazione:||Survey on yeast biodiversity in Georgian vineyards: a still pristine environment for the selection of non S. cerevisiae wine strains / I. Vigentini, D. Maghradze, M. Rossoni, S. Capponi, C. Picozzi, O. Failla, R. Foschino. ((Intervento presentato al 3. convegno Convegno nazionale Società Italiana di Microbiologia Agraria, Alimentare e Ambientale tenutosi a Bari nel 2012.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|