Ποσοτικός και μοριακός χαρακτηρισμός της μικροχλωρίδας της Κουμανδαρίας
Date Issued
2013
Author(s)
Advisor
Abstract
The complex microbial ecosystem of grapes, must and wine include yeast, fungi and bacteria with different physiological characteristics and effects upon wine production. Commandaria is the famous sweet wine of Cyprus made in the Commandaria area of the Limassol district and holds a protected designation of origin (PDO). Traditionally Commandaria produced by spontaneous fermentation using yeast strains found on the surface of grapes and in the winery environment. It is well established through research that non-Saccharomyces yeasts can make a positive contribution to the winemaking process. These yeast species could be used as part of a strategy to obtain different types of wines, especially in terms of aromatic profile. Quantitative and molecular characterization of the microflora associated with the fermentation of Commandaria has been scheduled in three axes that are directly related to its production. The three axes are the winery environment of Commandaria Museum where the fermentation takes place, the two types of indigenous Cyprus grapes Xynisteri and Mavro (fresh and dried) and the must during winemaking process in four phases. The microbiological investigation started with the plate count into five culture media. Fungi (yeast and hyphomycetes) and bacteria species identified by analysis of nucleotide sequences from rDNA and 16S regions respectively.
The yeast communities present on the samples belong to the genus Hanseniaspora, Aureobasidium, Pichia, Candida, Kluyveromyces, Saccharomyces, Rhodosporidium, Cryptococcus and Torulaspora. In this study we report the oenological properties of non-Saccharomyces yeasts through literature review. Acetic bacteria of the genus Acetobacter were identified in the winery environment. Lactic acid bacteria especially Oenococcus oeni species, which are the main agent of malolactic fermentation were not isolated. Environmental ubiquitous bacteria of the genus Enterococcus, Bacillus, Staphylococcus and Kocuria were identified both in the winery and the grapes, but do not have the ability to grow in wines. Species of the genus Aspergillus were identified on the grape microflora samples of grapes (fresh and dried) as well as at the first two phases of the fermentation. These fungi possibly producing ochratoxin A, are only active in the vineyard and sun drying process, although their metabolites may affect wine quality during grape processing but this requires further investigation.
The yeast communities present on the samples belong to the genus Hanseniaspora, Aureobasidium, Pichia, Candida, Kluyveromyces, Saccharomyces, Rhodosporidium, Cryptococcus and Torulaspora. In this study we report the oenological properties of non-Saccharomyces yeasts through literature review. Acetic bacteria of the genus Acetobacter were identified in the winery environment. Lactic acid bacteria especially Oenococcus oeni species, which are the main agent of malolactic fermentation were not isolated. Environmental ubiquitous bacteria of the genus Enterococcus, Bacillus, Staphylococcus and Kocuria were identified both in the winery and the grapes, but do not have the ability to grow in wines. Species of the genus Aspergillus were identified on the grape microflora samples of grapes (fresh and dried) as well as at the first two phases of the fermentation. These fungi possibly producing ochratoxin A, are only active in the vineyard and sun drying process, although their metabolites may affect wine quality during grape processing but this requires further investigation.
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