Application of Ultrasonics in Food Preservation and Processing

Influence of high power ultrasound on Brettanomyces and lactic acid bacteria in wine in continuous flow treatment

“…However, it is less likely that the conditions required for sporulation of yeast Dekkera could occur in wine. The results of the reduction in number of yeasts and bacteria in this study could therefore be explained as a combined effect of cavitation, formation of free radicals and peroxide, slightly elevated temperature and ethanol in wine, which leads to mechanical disintegration of cells and cell membrane deterioration by radicals [7,8,12]. D value refers to decimal reduction time and is the time required at a certain temperature to kill 90% of the organisms being studied.…”

“…Ultrasound range can be divided into three different frequency ranges [6][7][8] (0.1-1 W cm À2 ) and low frequency power ultrasound in the kHz range (20-100 kHz) with high sound intensity (10-1000 W cm À2 ). Power ultrasound (20-100 kHz) can provide the mechanical effect of cavitation in liquid systems which can alter physical and chemical properties of food depending on the type of material involved.…”

“…These highly oxidising species can have a significant effect on both biological and chemical species in aqueous solution [9]. The ultrasound-assisted microbial inactivation shows the different sensitivities based on size, shape and species of the microorganisms [7,8,[10][11][12]. According to the previous research data, the bigger cells show more inactivation than the smaller ones.…”

Effects of the High Power Ultrasound on Microorganisms in Fruit Juices

“…Physical and chemical factors affect fruits, vegetables and plant tissues by causing the excessive accumulation of reactive oxygen species (ROS). Reactive oxygen species can cause damage to membranes and other essential macromolecules such as proteins, DNA, and lipids [1].…”

“…Generally, cavitation is more effective on gram-positive bacteria, spores, spherical-shaped and small round cells [1]. Gram-positive bacteria are more resistant to ultrasound than gram-negative because of their thicker cells wall (tightly adherent layer of peptidoglycans) which gives them a better protection against ultrasound effects.…”