Conductive multi‐flash drying of mango slices: Vacuum pulse conditions on drying rate and product properties

In multi-flash drying, the pressure drop applied during the vacuum pulse and the number of heating vacuum pulses cycles (HVP) influence the fruit microstructure and texture. In this work, the effects of conductive multi-flash drying (KMFD) process variables on the drying kinetics, physical properties, and microstructure of mango slices were assessed. Different slopes of pressure drop (vacuum pulses of 0.98, 1.59, and 2.55 kPa s−1) and the number of HVP cycles (14 and 18 cycles for KMFD and a process with the application of 4 cycles followed by vacuum-drying KMFD-VD) were investigated. The number of HVP cycles allows obtaining both soft and crispy mangoes. Higher pressure drop slopes resulted in fruits with increased porosities (≈60%), compared with samples dried using the lower pressure drop slope (≈50%). The KMFD and KMFD-VD drying curves were similar, indicating that KMFD-VD presents operational advantages for obtaining dried fruits, reducing the number of heating-vacuum pulses. Practical applications Some fruits and vegetables have a short shelf life that limits their commercialization as fresh products and increase postharvest losses. Dehydration is an interesting alternative to the development of new products of fruits and vegetables with added value. In particular, the multi-flash drying is an innovative drying process based on the application of multiple cycles of heating-vacuum pulse to a solid food. Fruits and vegetables samples are heated (i.e., by heat conduction for the conductive multi-flash drying—KMFD) at moderate temperatures and submitted to a vacuum pulse, which causes flash drying and sample cooling. This method allows maintaining in dried products good physical–chemical properties and improving its texture. Moreover, according to the number of heating-vacuum pulse cycles and the pressure drop applied during these vacuum pulses, it is possible to obtain soft or crispy fruits. Thus, these variables can be used to control texture and produce high quality dried fruit.