Objetivo
The research project has an immediate multidisciplinary integrated approach: the role of sulphur dioxide during all stages of wine production will be studied in relation to the colour of red wine, the microbiological stability and sensory quality.
The interactions between malvidin-3-glucoside, the main anthocyanin in red wine made from Vitis vinifera grapes, and (+)-catechin, including the role of ferric ions and acetaldehyde was investigated in a model wine. In the presence of acetaldehyde the formation of 5 new compounds was determined by high performance liquid chromatography (HPLC); this formation was concurrent with rapid losses in the concentrations of malvidin-3-glucoside and catechin.
1 of the new compounds was a dimer consisting of malvidin 3-glucoside linked to catechin by an acetaldehyde bridge.
Concurrent with the losses in anthocyanins, qualitative and quantitative changes in visible colour were also observed, as determined by spectrophotometric measuremtns and colour changes were also monitored using the CIELAB 76 colour measurement system.
In the presence of 150 mg/kg sulphur dioxide there was an increase in extraction of colour during the first 6 days of fermentation; higher sulphur dioxide concentrations give more total phenols and total pigments in the wines. On storage all wines lost colour.
Other work achieved so far involve:
aquisition of a collection of 46 spoilage organisms;
development of a method to determine the concentration of free and total sulphur dioxide using the Tacussel sulphur dioxide analyzer, a headspace sensitive electrode (HSE);
determination of the most effective media for growth with minimal binding of sulphur dioxide;
study of the effect of different polymeric fractions from wine on the growth of yeasts and lactic acid bacteria;
testing 3 wines with differing concentrations of sulphur dioxide (0,75 and 150 ppm maximum) against wine spoilage organisms.
Points of interest to industry and consumers are:
the amount of sulphur dioxide required to make a stable wine is probably between 75 and 150 ppm;
the inhibitory moieties in wine (other than sulphur dioxide) appear to be in the fraction of lowest molecular weight, although this fraction also proved stim ulatory to some yeasts;
in model systems a dimer has been characterized as being more violet than the original wine pigments.
In the wine industry sulphur dioxide is generally used during processing and bulk storage, and a final addition is made just prior to bottling. No other single preservative fulfils the manifold properties of sulphur dioxide, since it has both antioxidant and antimicrobial activity. During bulk maturation of red wines polymers are formed some of which precipitate forming a deposit. Furthermore the colour of the wine changes to brownish red and the taste becomes softer. It is believed that the polymerized phenols may exhibit some antimicrobial action since red wine tends to become less prone to microbial spoilage as it matures.
Although there are legal guidelines regulating the maximum concentration of sulphur dioxide in bottled wine, there is little information about the optimum concentration required to prevent microbial spoilage and to ensure a stable wine colour and appearance without precipitates. More information is needed to establish the role of sulphur dioxide during the maturation of red wines with respect to the formation of stable coloured polymers and its action as an antimicrobial compound in conjunction with wine polymers. To minimize the complexity of this problem, we propose to study initially in model wines the following two aspects:
the role of sulphur dioxide in the polymerization of anthocyanins with other phenols, thereby establishing the optimum concentration of sulphur dioxide to obtain a desirable and stable wine colour and,
the sulphur dioxide tolerance of wine spoilage microorganisms and the synergistic effects between sulphur dioxide and other microbial inhibitors.
In order to validate the results obtained from work with model systems, similar studies will be done with wines. It will be necessary to establish the optimum sulphur dioxide concentrations at the various stages of wine processing that will give wine of stable coloration and microbiological characteristics. Furthermore, the effect of sulphur dioxide on the quality of the wines will be assessed by sensory analysis.
Work to be carried out:
studies using model wine systems to examine the role of sulphur dioxide in the polymerization of anthocyanins with other phenols, thereby establishing the optimum concentration of sulphur dioxide to obtain a desirable and stable wine colour;
studies on wine applying the information gained from model systems to establish the role of sulphur dioxide at various stages of processing (production, maturation and bottling), in the colour stability, microbiological stability and sensory quality of wine;
examination of the sulphur dioxide tolerance of wine spoilage organisms and the synergistic effects between sulphur dioxide and other microbial inhibitors, such as alcohol and selected wine phenolics.
Ámbito científico (EuroSciVoc)
CORDIS clasifica los proyectos con EuroSciVoc, una taxonomía plurilingüe de ámbitos científicos, mediante un proceso semiautomático basado en técnicas de procesamiento del lenguaje natural. Véas: El vocabulario científico europeo..
CORDIS clasifica los proyectos con EuroSciVoc, una taxonomía plurilingüe de ámbitos científicos, mediante un proceso semiautomático basado en técnicas de procesamiento del lenguaje natural. Véas: El vocabulario científico europeo..
- ciencias agrícolas agricultura, silvicultura y pesca agricultura horticultura viticultura
- ingeniería y tecnología ingeniería de materiales colores
- ciencias naturales ciencias químicas química orgánica ácido orgánico
- ciencias naturales ciencias químicas ciencia de polímeros
- ingeniería y tecnología biotecnología industrial tecnología de bioprocesos fermentación
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Programa(s)
Programas de financiación plurianuales que definen las prioridades de la UE en materia de investigación e innovación.
Programas de financiación plurianuales que definen las prioridades de la UE en materia de investigación e innovación.
Tema(s)
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Las convocatorias de propuestas se dividen en temas. Un tema define una materia o área específica para la que los solicitantes pueden presentar propuestas. La descripción de un tema comprende su alcance específico y la repercusión prevista del proyecto financiado.
Convocatoria de propuestas
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Procedimiento para invitar a los solicitantes a presentar propuestas de proyectos con el objetivo de obtener financiación de la UE.
Régimen de financiación
Régimen de financiación (o «Tipo de acción») dentro de un programa con características comunes. Especifica: el alcance de lo que se financia; el porcentaje de reembolso; los criterios específicos de evaluación para optar a la financiación; y el uso de formas simplificadas de costes como los importes a tanto alzado.
Régimen de financiación (o «Tipo de acción») dentro de un programa con características comunes. Especifica: el alcance de lo que se financia; el porcentaje de reembolso; los criterios específicos de evaluación para optar a la financiación; y el uso de formas simplificadas de costes como los importes a tanto alzado.
Coordinador
RG6 2EF Reading
Reino Unido
Los costes totales en que ha incurrido esta organización para participar en el proyecto, incluidos los costes directos e indirectos. Este importe es un subconjunto del presupuesto total del proyecto.