Application of Non-Thermal Technologies for Minimally Processed Fruits and Vegetables Quality Increase and Product Innovation

Abstract

A wide variety of minimally processed fruits and vegetables has been developed in order to respond to the increasing consumers’ demands for ready-to-eat and ready-to-use fruits and vegetables products. Creating innovative products with high quality and pleasing the consumers palate is always a concern for the food industry. The present thesis mainly discusses the application of non-thermal technologies such as Osmotic Dehydration (OD), High Hydrostatic Pressure (HHP), Pulsed Electric Fields (PEF) and Vacuum impregnation (VI) aimed at product innovation and quality improvement for minimally processed fruits and vegetables. The main results related to the applied non-thermal techniques confirmed their potentiality but also the need to optimize them as a function of raw material characteristics and final product target. The application of HHP was evaluated as an alternative to heat treatment prior to OD for the production of candied green plums, as it was shown to efficiently accelerate the mass transfer during the OD process, allowing to reduce the dehydration time from more than 5 days to about 2 days. HPP allowed to maintain higher firmness values and a greener colour of the final product, to retain the antioxidant compounds content and the antioxidant activity and to improve the aromatic profile (in terms of total amount and number of volatile components) of the final product. The pre-treatment with PEF in raw potatoes was proven effective for reducing the final acrylamide content in deep-fat fried potato crisps by favoring the release of acrylamide precursors during the further dipping, with only slight modifications of the final quality of the product. VI was applied for the aromatic enrichment of potato sticks showing a good potentiality for product innovation. However, based on the characteristics of the raw materials, the process needs to be improved in order to guarantee the quality of the product during storage.