Improving quality of dried fruits: A comparison between conductive multi-flash and traditional drying methods

- KMFD results in more porous and crispier fruits than other drying processes.
- KMFD allow the production of high quality dried mangoes in short times.
- KMFD was performed at low temperatures resulting in small color changes.
- Rehydration and carotenoids in KMFD and freeze-dried samples are similar.

Conductive multi-flash drying (KMFD) is an innovative drying process based on the application of multiple cycles of heating-vacuum pulse to a food to be dried. This method allows obtaining crispy-and-dried products with appealing characteristics. The objective of this study was to compare different drying methods (KMFD, air-drying, vacuum drying and freeze-drying) with respect to drying kinetics and physical properties of dried mangoes (porosity, microstructure, color, and mechanical properties). The influence of these drying methods on carotenoids concentration and rehydration were also investigated. Mango samples were dried from 5.30 g/g moisture (dry base) to 0.01 g/g (aw = 0.293) in 2.25 h by the KMFD, which was much shorter than the drying times observed for freeze-drying (16 h), air-drying (12 h) and vacuum drying (8 h). Porosity and texture of samples dried by KMFD were similar to the observed for freeze-dried samples, despite the different microstructures. Carotenoids concentration of freeze-dried samples was 1.6 times higher than that from KMFD, which was in turn 1.27 times higher than that from air-dried samples. KMFD is a new and innovative drying process that allows the production of crispy mangoes in reduced drying times, with carotenoids contents and rehydration ability similar to freeze-dried samples.