Pulsed Electric Field-Assisted Cold Maceration of Cabernet franc and Cabernet Sauvignon Grapes

Abstract

The effect of pulsed electric field treatment on the cold maceration (6 days at 6ºC) of Cabernet franc and Cabernet Sauvignon grapes was investigated. The parameters of grape juice pH, Brix, color intensity, anthocyanin and total polyphenol contents, and free radical scavenging activity were determined during the entire period of cold maceration. The high pulsed electric field treatment (5 kV/cm, 1 ms, 48 kJ/kg) enhanced significantly the extraction of flavonoid (quercetin 3-β-D-glucoside and epicatechin gallate) components after subsequent cold maceration of red grapes. The high treatment also enhanced the color intensity (75% for Cabernet franc and 68% for Cabernet Sauvignon) and increased the anthocyanin content of juice (from 87 to 172 mg/L for Cabernet franc and 168 to 269 mg/L for Cabernet Sauvignon). The moderate pulsed electric field treatments (400 and 800 V/cm, 50 to 100 ms) were less effective for polyphenol extraction but consumed less energy (3 to 40 kJ/kg). The wines obtained from treated Cabernet franc and Cabernet Sauvignon musts had higher phenolic content and color intensity during the alcoholic fermentation period than wines obtained from the untreated musts.