Determination of polyphenolic composition and chromatic characteristics in Cabernet Sauvignon and Graševina wines after high intensity ultrasound treatment

Abstract

Potencijalna upotreba ultrazvuka visoke snage za ubrzavanje procesa starenja vina je nedovoljno istražena. To onemogućava određivanje mogućnosti primjene ultrazvuka visoke snage u tehnologiji vina. Prirodno starenje vina je dugotrajan proces koji iziskuje mnogo truda i troškova. Cilj ovog istraživanja bio je ispitati utjecaj ultrazvuka visoke snage na kemijski sastav vina Graševina i Cabernet Sauvignon. Također je ispitivan i utjecaj ultrazvuka visoke snage na kromatske karakteristike ovih vina. Tretman je proveden uranjanjem ultrazvučne sonde različitih promjera (12,7, 19,1 i 25,4 mm) i amplituda (25, 50, 75 i 100 %) u trajanju od 6 minuta. Koncentracija ukupnih fenola određena je Folin-Ciocalteu metodom, ukupnih antocijana pomoću metode bazirane na dodatku otopine natrij hidrogensulfita, a ukupni tanini određeni su Bate-Smith metodom. Kromatske karakteristike vina određivale su se CIE L*a*b* metodom. Utvrđeno je da tretman ultrazvukom visoke snage uzrokuje smanjenje svih ispitivanih parametara. Najveći učinak postigao se pri korištenju manjih promjera sonde i većim amplitudama.The potential use of high power ultrasound to accelerate aging process of wine has been insufficiently explored. This prevents the possibility of determining the application of high power ultrasound in wine technology. Natural wine aging is a long-lasting process that requires a lot of effort and expenses. The aim of this thesis was to examine the effect of high power ultrasound on chemical composition of Graševina and Cabernet Sauvignon wines. Also, the effect of high power ultrasound on wine chromatic characteristics was examined. The treatment was performed by immersing ultrasonic probe with different diameters (12.7, 19.1 and 25.4 mm) and amplitudes (25, 50, 75 i 100 %) within 6 minutes. The concentration of total phenols are determined by the Folin-Ciocalte method, while concentration of total anthocyanins by the Bate-Smith method. Wine chromatic characteristics were determined by CIE L*a*b method. It was found that high power ultrasound treatment causes a decrease in all tested parameters. The greatest effect was achieved while using ultrasonic probe with smaller diameters and larger amplitudes