Emilio Celotti, * Massimo Pivetta, and Elisabetta Bellantuono
*TMCI-Padovan S-p.A. V. Veneto (Italy); Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Via Caduti del Lavoro, 7, Via Sondrio 2/A, V. Veneto (TV) 31029 – Udine (UD) 33100, Italy (emilio.celotti@uniud.it)

We examined the effects of cavitation induced by ultrasound on different winemaking phases, in particular skin maceration, yeast lysis, color evolution, and lees filterability. An experimental design was created to optimize ultrasound conditions like time, amplitude, and frequency, depending on the product treated and enological objective. Tests that gave best results in the laboratory were compared to traditional enological practices. For skin extraction, best results occurred using 90% amplitude for 3 to 5 min at a frequency between 20 and 27 kHz, which significantly increased total phenolic compounds. Ultrasound of crushed grapes before vinification significantly reduced maceration time of red grapes (up to 50%) and white grape maceration for aroma extraction could be avoided. To evaluate the effect on yeast cells after fermentation, some ultrasound trials were performed on fine lees from white wines, leading to a significant rise in yeast soluble cell compounds. This increment implies a reduced aging period on lees compared with conventional techniques. There was also a significant effect of ultrasound treatment on juice and wine clarification lees that increased the tangential filtration performance in liquid recovery and treatment cost. The effect of ultrasound on tannins and anthocyanin evolution was tested on young red wines, in order to investigate the changes during aging process. Good results were reached in each test and the use of ultrasound improved tannin polymerization and color stability. An industrial plant was made for winery application. Pilot scale application in different viticulture regions around the world, confirmed the benefits of different applications using few minutes of treatment. Technological factors (time and amplitude) must be calibrated depending on the specific enological application.

Funding Support: TMCI-Padovan S.p.a. V.Veneto (Italy)