Adjustment of milling, mash electroporation and pressing for the development of a PEF assisted juice production in industrial scale

Pulsed electric field (PEF) assisted juice recovery from apple and carrot was performed. Different mash structures were subjected to PEF treatment at two different treatment intensity levels. Solid-liquid separation was performed using four different systems: belt press, rack-and-cloth press, hydraulic filter press and decanter. The combination of milling and PEF treatment provided a method for the independent control of particle size and cell disintegration. An increase of juice yield after PEF treatment was found for apple mash in the range of 0-11% and for carrot mash in the range of 8-31% depending on mash structure and de-juicing system. It was the aim of the study to investigate the interdependency of the aforementioned processing steps in order to develop adjustment concepts for the maximization of the juice yield increase by PEF and to evaluate the impact on related juice quality parameters. Industrial relevance: Pulsed electric field (PEF) treatment of fruit and vegetable mashes and the resulting cell disintegration is a promising alternative to conventional enzymatic maceration or thermal disintegration to improve juice yields. PEF equipment is commercially available for industrial scale processing of fruit and vegetable mashes. Despite the uncomplicated technical implementation of the PEF system in the existing processing line, related processing steps such as milling and pressing need to be adjusted in order to maximize the beneficial PEF effect on the juice yield. The present study provides the basis for the required process analysis and optimization. (C) 2011 Elsevier Ltd. All rights reserved.