Application of Plasma Spray Reactor to Inactivate the Osmotolerant Yeast Zygosaccharomyces rouxii in Apple Juice

Abstract

The inactivation effect of plasma spray reactor on Zygosaccharomyces rouxii in apple juice was studied as a function of plasma discharge voltages, gas flow rate and liquid flow rate, and the morphological changes of the cells and the effect of this treatment on apple juice quality were evaluated. In this study, a plasma spray reactor was used to treat 0.5 L of apple juice for 30 min at a discharge voltage of 21 kV, a gas flow rate of 150 L/h, and a liquid flow rate of 9.0 L/h. The number of osmotolerant yeast cells in apple juice decreased significantly. Plasma spray reactor treatment caused cell rupture, thus resulting in the inactivation of yeast cells. Under the optimal parameters, this treatment increased the pH of apple juice slightly, but did not cause any significant changes in the titratable acid or reducing sugar concentration (P > 0.05) and resulted in no significant changes in the major major volatile compounds in apple juice. This study may provide a reference for the application of plasma spray reactor in apple juice processing.

Keywords

• plasma spray reactor; osmotolerant yeast; apple juice; inactivation