Nonthermal processing of apple and kiwifruit slices for quality and stability increase: Review

Nonthermal techniques for fruit processing can be a good alternative to heat required methods, in order to produce minimally processed fruit and vegetables. This work presents the state of the art of some applications of osmotic dehydration (OD), vacuum impregnation (VI) and ultrasound (US) treatments on minimally processed apple and kiwifruit, in order to show the potentiality of these techniques to preserve their quality and stability. The application of OD process resulted in several positive effect on kiwifruit overall quality and stability. Despite the texture improvement and the color maintenance, a decrease of water mobility and availability was observed. The application of US promoted the further improvement of water/solutes exchange with the modification of kiwifruit structure. VI instead was applied on apple tissue promoting a considerable weight gain and density changes. The microscopic assessment showed the solutes up-take inside the cells by cell membrane vesiculation.