Enhancing moisture transfer and quality attributes of tomato slices through synergistic cold plasma and Osmodehydration pretreatments during infrared-assisted pulsed vacuum drying

Abstract

The present study examines the impacts of combined cold plasma treated water (PW) and osmodehydration (OD) pretreatment (PO), and operation parameters like PW duration and voltage of treatment on the dehydration, functional and sensory characteristics of sliced tomato fruits subjected to simultaneous infrared-assisted pulsed vacuum drying (IR-PVD). From the results, PO pretreatment modified the surface structures by the formation of microchannels and cavities through impingements from the reactive species (RS), and was improved due to increased treatment duration and voltage, and resulted in accelerating the transfer of moisture from the slices to the surroundings during the dehydration process. Consequently, PO pretreatment achieved an enhancement in the moisture diffusivity by up to 64.83%, shortened the total drying time by up to 40%, and presented substantial improvements in the physicochemical properties including vitamin C, lycopene, colour, total soluble solids, phenolic and flavonoid contents, and overall human acceptability. However, significant decreases in rehydration and hardness properties were shown compared with control, and higher rehydration by up to 21.66% at higher treatment duration and voltage when compared with OD pretreatment. Overall, PO pretreatment incited an effective moisture removal and retention of vital physicochemical and bioactive constituents in the slices due to the activities of plasma injected RS. This study provides an empirical basis for the application of PO during IR-PVD of fruits and vegetables and demonstrated as a suitable energy-saving alternative for improving the conventional OD of foods in the industry.