Projects / Programmes
Influence of interactions between yeasts on wine fermentation and maturation
| Code |
Science |
Field |
Subfield |
| 4.06.00 |
Biotechnical sciences |
Biotechnology |
|
| Code |
Science |
Field |
| B230 |
Biomedical sciences |
Microbiology, bacteriology, virology, mycology |
| T430 |
Technological sciences |
Food and drink technology |
interactions, yeast, wine, signaling molecules, spoilage yeast, mycotoxins, agrichemicals
Researchers (17)
Organisations (2)
Abstract
Contemporary consumer demands for wine that has enjoyable sensory experiences and that possesses unique qualities that differentiate it from other wines. From these facts, wine microbiologists have focused on enhancing flavour diversity and appeal of wines by controlled fermentations with multiple species and strains. Results of these studies showed that the chemical composition of musts produced in mixed-culture ferments are different from the profiles of chemical substances produced in single-cultures. Based on these findings it is concluded that in mixed-cultures, one species or strain may impact on the metabolic behaviour of the others. However, the mechanisms of these interactions are not elucidated and require more precise description and understanding to enable practical development and application. On this basis, the aims of this project are to elucidate the mechanisms which are responsible for different yeast species and strain kinetics, different spectra of metabolite formation and yeast persistence during wine fermentations. The project work will be divided into three phases: in the first phase we will identify the chemical nature of the sensing molecules and their effect on expression of the proteins of the cell wall and genes involved in fermentative aroma production of wine yeast. During the second phase we will monitor the dynamics of yeast communication molecules under oenological conditions and the third phase will consider the interactions between wine yeasts and spoilage yeasts during the process of autolysis and their influence on wine safety. With the project we want to elucidate the interactions between different strains and species of wine yeasts during must fermentation and with this we would like to assure better control over the course of fermentation and quality of the end product. On the other hand the aims of the project are focused on the product with defined sensorial properties and assured safety.
Significance for science
Wine is the product of interaction between complex microflora of grape must which end result is due to various influences difficult to predict because of different combinations of microbes, heterogeneous composition of grape juice and environmental parameters. Based on the fact that the chemical composition of musts produced in mixed-culture fermentations are different from the profiles of chemical substances produced in single-cultures it is most likely that in fermentations with mixed cultures interactions between species and strains occur which consequently leads to a different metabolic response of the leading wine yeast. We have established a methodological approach to isolate and identify these communication molecules. With understanding of these interactions it is possible that mixed-culture wine fermentations will be developed and brought into application. The project work demands interdisciplinary access. With the determination of response on the level of simple aromatic molecules and proteins we deduced the responses on the metabolic level and further the end-product quality. The methodology of the project is therefore very heterogeneous: chemical analytical methods for identifying signalling molecules, methodology for tracking the wine fermentation process, molecular methods for selective yeast detection and methodology for determination of chemical contaminants in wine. During the project work was focused on study of mechanisms of interactions between yeast colonies and between individual cells in liquid media. The main objects of the study were extracellular proteins for which we determined their role as signal molecules. The method for their isolation from media was developed and the procedure for their purification and detection was later optimized. The co-workers of the Agricultural institute of Slovenia developed the method for measuring concentrations of volatile communication molecules which will be used later for studying different environmental factors influencing communication between different species strains of wine yeasts during must fermentation. The work was focused on development of methodology for characterisation of molecules which we can detect and can be used for study of different environmental factors, which effect various wine species and strains during wine fermentation. These tools will enable further studies of complex relationships among species and strains in natural and men made milieu designed by composite starter cultures. Special attention will be given in the future also to organic wines, with total reduction of sulphur what is the challenge, which can be studied with this approach.
Significance for the country
Food production is an important part of the Slovenian industry. A special group of food productions are the processes which involve microorganisms as working organisms. Wine production with spontaneous fermentation is caching great attention with conscious consumers. The research group is focusing on the yeast as a working organism during the wine production procedure which production is characteristic for Slovenian culture. Knowledge established in this project will be efficiently used in novel bioprocess concept development with is based on product with low sulphur content, with corresponds to the trend in additive reduction due to alegenicity issues
A second important impact for Slovenia has the project also on gaining the knowledge and passing this knowledge on different segments of the state - from food producers to official governmental institutions which are responsible for food quality monitoring. An important benefit is also the knowledge transfer to new young and perspective researchers (graduate and PhD students).
Most important scientific results
Annual report
2008,
2009,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2008,
2009,
final report,
complete report on dLib.si
