Liquid food pasteurization by pulsed electric fields: dimensionless analysis via Sherwood number for a comprehensive understanding

摘要

Pasteurization of liquid foods by pulsed electric fields has been a subject of research for many years. The biological membranes are damaged by the process of electroporation, allowing leakage of internal compounds and possibly leading to subsequent cell lysis. This work is a continuation and extension of a former study that correlated biological inactivation with a modified Sherwood number. The Sherwood number is normally used to describe mass transfer under an electromotive force. In the present work, the Sherwood model was modified; the electric field intensity E was replaced by the specific energy W (specif) a more general parameter, particularly when the chamber design results in a non-constant electric field. To deal with particular parameters, the length of the treatment chamber was also introduced. Experimental results were compared with the results obtained via the new model we propose. In addition, the model was able to satisfactorily describe results previously published in the literature. The model proposed is thus suitable for describing microbial inactivation in various systems, according to the chamber geometry, hydraulic regimes, electric signal shapes and durations, and the types of microorganisms (yeast and rod bacteria).