Effect of High-Power Ultrasound Treatment on Bioactive Compound Content and Chromatic Characteristics of Red Wines

Abstract

The objective of this work was to investigate, at a laboratory scale, the effect of ultrasound treatment (frequency 20 kHz) on the extraction of total phenolic compounds and monomeric anthocyanins from crushed Merlot grapes in order to reduce maceration time. Antioxidant capacity expressed as ferric reducing antioxidant power (FRAP) and chromatic properties were also investigated. Microvinification was performed on samples both sonicated with a probe-type ultrasonic instrument and untreated (control) and the maceration operation was carried out with sequential extraction (after 3, 5 and 7 days) to evaluate the effect of two factors such as amplitude (A), 70 and 90% and treatment time (t), 3, 4 and 5 minutes on the extraction kinetics of bioactive compounds and chromatic characteristics of the samples. The results showed that throughout the maceration process, the sonicated samples exhibited higher levels of bioactive compounds and chromatic characteristics compared to the control, with the values obtained correlating with maceration time, US treatment time and amplitude. Improvement in all investigated characteristics is evident for ultrasound treated samples compared to untreated ones. Our study provided useful data concerning the impact of ultrasound on the bioactive properties and sensory attributes of red wine, thus offering a theoretical basis for the implementation of this technique in winemaking.

Keywords

• ultrasound
• red winemaking
• maceration
• phenolic compounds
• chromatic properties