The volatile substances with fruity/floral character (table 3) are removed in different percentage according to the type of wine, of bentonite and of the dosage used. In particular, in wine 2, the experimental preparation produces a reduction always lower at all dosages, while in wine 1 Superbenton results to be the less invasive. For those clays, a removal of small quantity at the dosage of 20 g/hl, reaching 50% at 100 g/hl, is observed in both wines. The results of the fi rst year experimentation showed that the “wine matrix” affects the effectiveness and the affi nity of bentonite. For instance: in case of a product rich in macromolecules deriving from the yeasts, the deproteinising effect of the clays is less important, probably because the colloidal system reduces their effectiveness and because part of the macromolecules can have the same charge of the adjuvant. The less invasive effect on the wine with fuller body than the younger wine concerns also the aromatic component; in fact, reductions that can be compared with those obtained on the younger product are obtained with higher dosages of bentonite. Besides it can be observed that the experimental bentonite is more effective on the more complex wine, while Top Gran DC seems to better adapt to the younger wine. As to the behaviour towards the volatile fraction of fermentative origin of the wine, it was proved that the removal is not non-specific, yet it differs depending on the family of molecules involved and the type of bentonite used. This fact, according to the type of product, can promote an improvement of the pleasantness and fineness of the bouquet when, for instance, the herbaceous and juicy notes are mitigated and there is a moderate reduction of the fl oral and fruity notes.
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by Roberta Dordoni1, Milena Lambri1 and Maria Manara2
1Istituto di Enologia e Ingegneria Agro-Alimentare, FacoltĂ di Agraria,
UniversitĂ Cattolica del Sacro Cuore, Piacenza
2R&D, Dal Cin Gildo S.p.A., Sesto San Giovanni (MI)
