High-power ultrasound on the protein stability of white wines: Preliminary study of amplitude and sonication time

Abstract

White wines can be negatively affected by the formation of an undesirable protein haze. This sensory defect is prevented by specific fining agents, principally bentonite, which can negatively affect wine sensory characteristics through the removal of color and aroma compounds. Recent studies have focused on the potential application of ultrasound in the food industry, aimed to modify the protein conformations and functional properties for several purposes. The effect of amplitude (30%, 60%, and 90%) and sonication time (5 and 10 min) on the protein stability of two different white wines was evaluated and then compared with bentonite fining in this study. Significant effects of sonication were found. Higher amplitude and treatment time induced an increase in protein stability, confirmed by the lower heat test value (0.36 ± 0.14), comparable to that obtained after bentonite fining of untreated wine (0.12 ± 0.02). Positive effects were detected on protein charge neutralization and surface electrical charges, thus suggesting some positive conformational changes of wine proteins.Ultrasound could be considered as a technology to prevent protein precipitation and to reduce the quantity of fining agents used by wineries, but their effectiveness could be strictly related to the initial protein profile.