## 5 Conclusions
### Basic Mechanisms of the Pre-Treatments Applied  
Drying is a technology widely used to obtain shelf-stable food products and snacks. However, drying is a time- and energy-consuming process, therefore the application of pre-treatments such as pulsed electric field (PEF) and osmotic dehydration (OD) alone or in combination could be important both for energy saving and preservation of the final food quality.  
PEF technology consists in the application of pulses of high voltage and short duration (ms-us-ns) to a biological material placed between two electrodes. The application of the external electric field (Ee) to the biological material promotes the electroporation of the tissue, which could be of different extents, reversible or irreversible, as it is shown in Figure 5. When the applied electric field strength (Ee) exceeds a critical value (Ee \(>\) Ec), a temporary membrane permeabilization takes place. However, if the electric field is still below the irreversible electroporation threshold, cells can recover their integrity and remain viable after the electric field exposure. The reversible electroporation (the created pores reseal immediately after removing the electrical field) could be used to incorporate different functional substances into the vegetal tissue, ensuring the survival of the electrically stimulated cells. On the other hand, when the electric field strength greatly exceeds Ec values (Ee \(>>\) Ec), a permanent membrane permeabilization takes place. This phenomenon leads to extensive leakage of the intracellular content and cell death, which find wild applications in the microbial inactivation of liquid foods and for the cell disintegration of biological tissues [40].  
Electroporation and, consequently, cell disintegration of biological tissues upon the application of a low/moderate electric field strength (0.1-5 kV/cm) can be used for the enhancement of mass and heat-based processes of structure modification [41].  
Osmotic dehydration is a partial dewatering impregnation process, usually carried out by immersion of a cellular tissue, which is characterized by semipermeable membranes, in hypertonic solution. Thanks to the differences in the water chemical potential between the tissue and the osmotic solution, an important mass transfer phenomenon can occur (Figure 5). There is a water loss from the tissue into the osmotic solution, while at the same time, there is a simultaneous counter-diffusion of solutes from the concentrated solution into the tissue. During osmotic dehydration, the membrane responsible for osmotic transport progressively loses its selectivity, therefore a leakage of the natural solutes present in the cells (e.g., vitamins, pigments) can also occur [42].  
Osmotic dehydration can be used as a pre-treatment for fruit and vegetables intended for further processing, like, for example, drying, contributing to the reduction in the drying time [43].  
**Author Contributions:** Conceptualization, C.M., U.T. and M.D.R.; methodology, C.M., U.T. and S.T.; software, C.M. and U.T.; validation, C.M., U.T. and S.T.; formal analysis, C.M.; investigation, C.M. and U.T.; resources, M.D.R.; data curation, C.M. and U.T.; writing--original draft preparation, C.M. and U.T.; writing--review and editing, C.M., U.T., S.T., M.D.R., P.R. and S.R.; visualization, C.M., U.T.; supervision, P.R. and S.R.; project administration, M.D.R.; funding acquisition, M.D.R. All authors have read and agreed to the published version of the manuscript.  
**Funding:** Support for this project was provided by Emilia-Romagna Region within the PSR 2014-2020 Project (Focus Area 5 C).  
**Conflicts of Interest:** The authors declare no conflict of interest.