The evolution of food technologies through the use of the so-called emerging technologies lays the basis for obtaining products with at least partial stabilization level against microbial alterations with minimal modifications of the intrinsic sensory and nutritional qualities of the finished products. High hydrostatic pressures, pulsed electric fields, cold plasma and osmodehydration can be used for the processing of sweet and sour cherries, with obtaining products of good quality and medium-long shelf-life avoiding highly impacting thermal treatments. High hydrostatic pressure can be used to obtain a partial stabilization of pitted cherries to prolong their shelf-life up to 15 days in refrigerated conditions without any severe thermal treatments. High pressure homogenization could be instead useful to multiple purposes like partial microbial stabilization, viscosity changes and bioactive compounds incapsulation of cherry juices. Water removal without state exchanges can be performed using the direct osmosis dewatering technology. Up to the 70 % of the initial water had been showed to be removed with the immersion of sweet cherries to a Dalla Rosa 58 hypertonic solution taking advantages of the difference of osmotic pressure between the fruits and the solution, even with any increase of temperature and very low energy demand. Since this technology is time consuming, pre-treatments like application of Ultrasounds or Pulsed Electric Fields (PEF) have been successfully applied in fruit osmotic dewatering. Furthermore, combining the osmotic dehydration and vacuum pulses it has been possible to introduce interesting enriching components like bioactive substances, probiotics and vitamins to reinforce the healthy contents of cherries. Eventually, surface treatments could be adopted to optimize the cherry skin permeability. Among the new technologies potentially able to help the sanitation and thus the extension of the cherry shel-life, cold plasma could be applied to decontaminate the fruit surface also in this case without any temperature increase. The packaging of the fresh and finished products through the use of modified atmosphere pakaging (MAP), combined with the choice of the most suitable flexible films can be a further key to improve the shelf life of the products.
Effect of pulsed electric fields pre-treatment on mass transport during the osmotic dehydration of organic kiwifruit
