Delineation significance in viticultural zoning: examples in the Southern Côtes-du-Rhône

The knowledge about the molecular fraction associated to white wines oxidative stability is still poorly understood.

Solo attraverso un adeguato intervento di estirpazione e reimpianto dei vigneti è possibile preservare, adeguare e valorizzare il patrimonio viticolo e le produzioni che da esso derivano.
Il reimpianto dei vigneti è pertanto da intendersi come una normale pratica agricola, alla pari della rimonta di stalla in campo zootecnico, ma può assumere toni problematici quando, come si verifica adesso in Toscana per una serie di circostanze legate alla profonda trasfor­mazione della viticoltura avvenuta negli ultimi 30 anni, troppi impianti giungono contem­poraneamente a fine ciclo produttivo e devono essere rinnovati.

Postharvest dehydration is a widely employed technique in winemaking to enhance sugar concentration and secondary metabolites from grapes. Different grape varieties exhibit varying responses in terms of dehydration rate and the resulting chemical composition.

Rapid and accurate quantification of grape berry phenolics, anthocyanins and tannins, and identification of grape varieties are both important for effective quality control of harvesting and initial processing for wine making. Current reference technologies including High Performance Liquid Chromatography (HPLC) can be rate limiting and too complex and expensive for effective field operations

Mannoproteins (MPs) are proteoglycans from the outmost layer of yeast cell walls released into wine during alcoholic fermentation and ageing on lees processes. The use of commercial preparations of mannoproteins as additives to improve wine stability with regards to the crystallization of tartaric salts and to prevent protein haze in the case of white and rosé wines is authorized by the OIV.
Regarding red wines and polyphenols, mannoproteins are described as able to improve their colloidal stability and modulate the astringent effect of condensed tannins. The latter interact with salivary proteins forming insoluble aggregates that cause a loss of lubrication in the mouth and promote a drying and puckering sensation. However, neither the interaction mechanisms involved in mannoproteins capacity to impact astringency nor the structure-function relationships related to this property are fully understood.