Winery Trial on Application of Pulsed Electric Fields for Improving Vinification of Garnacha Grapes

The potential of pulsed electric fields (PEF) to improve polyphenol extraction during winemaking was investigated in a winery trial. Four thousand five hundred kilograms of Garnacha grapes were treated with PEF (4.3 kV/cm, 60 mu s) at a flow of 1,900 kg/h using a collinear treatment chamber. Wine obtained from PEF-treated grapes with a maceration time of 7 days was compared with wines obtained from untreated and PEF-treated grapes with the current maceration time (14 days) used by the winery. After 7 days of maceration, the color intensity, anthocyanin content, and polyphenol index in the tank containing grapes treated by PEF were 12.5, 25, and 23.5 % higher, respectively, than in the tank containing untreated grapes. However, after 14 days of maceration, no significant differences were observed between the control wine and the wine obtained from grapes treated by PEF for these three indices. An HPLC analysis indicated that the concentrations of major individual phenolic compounds were similar among the three wines at bottling. A sensory analysis revealed that the wine obtained from PEF-treated grapes macerated for 7 days was significantly preferable to the other two wines.