The effect of high power ultrasound on phenolic composition, chromatic characteristics, and aroma compounds of red wines
Natka Ćurko, Karla Kelšin*, Anet Režek Jambrak, Marina Tomašević, L. Gracin,
Vlatka Poturica, E. Ružman, Karin Kovačević Ganić
University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia
original scientific paper
High power ultrasound (HPU) is a novel, non-thermal technology the application of which has been primarily evaluated in managing food quality. The application of high power ultrasound in wine technology is therefore directed at modulating microbial activity during fermentation, extraction of phenolic and aroma compounds from grapes to must, as well as at accelerating aging reactions in wine. The main aim of this article was to evaluate the effect of different HPU process parameters on sustaining the phenolic and aroma composition of red wine and its colour characteristics. Three different red wines, including Cabernet Sauvignon, Merlot, and Plavac mali, were treated with high power ultrasound (20kHz), considering the variations in ultrasound probe diameter size (12.7 and 19 mm), amplitude level (20, 30, and 40 %), and processing time (2, 4, and 6 minutes). Total polyphenol content, total anthocyanin concentration, and chromatic characteristics were analysed by spectrophotometry, free anthocyanins were analysed by high performance liquid chromatography, and wine aroma compounds were analysed by gas chromatography combined with solid-phase microextraction. The obtained results show that ultrasonic irradiation induces chemical changes in phenolic composition, chromatic characteristics, and aroma compounds concentration, and accelerates chemical reactions responsible for wine aging. The intensity of the mentioned chemical changes depends on the selected processing parameters and on the treated variety. Among three different parameters, the selection of the probe diameter was showed to be most significant factor influencing chemical composition, followed by the amplitude level and processing time. The smaller diameter probe size (12.7 mm), lowest amplitude (20%), and a shorter processing time (2 minutes) showed a more favourable and lighter effect on the chemical composition of the treated red wines.
Keywords: high power ultrasound, red wine, polyphenols, colour, aroma