Controlling B. bruxellensis with Pulsed Electric Fields: Optimization of industrial protocols and impact on the wine profile

Abstract

Pulsed electric field application for microbial inactivation of wine spoilage microorganisms has recently become a point of interest among scientific and industry peers. B. bruxellensis is considered one of the most undesirable spoilage yeast in wines. Thus, this assay has the objective of contributing to better understanding the effect of PEF, not only on the inactivation of B. bruxellensis and impact on Total Yeast population, but also on physico-chemical and sensorial quality. 2 sets of red wine were subjected to a 15 kV/cm and 35 kJ/Kg PEF treatment at pilot-plant scale (240 L/h, 4 bar); one wine was naturally contaminated with B. bruxellensis, being used for microbial assessment, while the wine deemed free of contamination was subjected to physico-chemical and sensorial analysis prior and after the application of PEF. B. bruxellensis was effectively inactivated using a conservative PEF treatment of 15 kV/cm and 35 kJ/kg, resulting in a reduction from 2.467 x 10^3 viable cells/mL to below the detection limit of <150 viable cells/mK; Total Yeast Count decreased 80,66%. The treatment posed a ∆T = +8,5 ºC. Sensorial analysis concluded no significative differences. Small, but significant differences were found at physico-chemical level.