Drying strawberry slices: A comparative study of electrohydrodynamic, hot air, and electrohydrodynamic-hot air techniques

Abstract

The investigation encompassed an examination of the drying durations, modeling, and quality attributes (color, rehydration capacity, microstructural features, total soluble solid [TSS], and pH values) of strawberry slices subjected to diverse drying methodologies, namely electrohydrodynamic (EHD), EHD-hot air, and hot air processes. Furthermore, 10 distinct thin-layer drying models were applied, and their goodness-of-fit was assessed to identify the most suitable model for the drying process. This analysis encompassed applying two distinct temperatures (50°C and 55°C), and voltage levels (20 and 30 kV). The EHD method yielded the lengthiest drying durations for the strawberry samples, with hot air and EHD-hot air drying techniques subsequent in descending order of drying time. The outcomes of the modeling analyses demonstrated that the thin-layer drying behaviors of used drying methods were best described by the Midilli et al. and Wang and Singh models in terms of their goodness-of-fit. A decline in the L* values was noted with the elevation of temperature in the hot air drying method and with the escalation of voltage in the EHD drying. The minimum a* value was detected in the hot air drying method conducted at 55°C. The rehydration capacity of strawberry samples subjected to the EHD and EHD-hot air combination drying methods (except 20 kV-55°C) did not exhibit any statistically significant variation in response to different voltage settings. Although the structure of strawberry samples dried with 20 kV application was observed as smoother, cracks occurred on the product surface in other drying applications. In hot air and EHD methods, varying temperature and volt applications did not show a significant effect on TSS and pH values. As a result, it has been seen that EHD technology, which is a promising drying method used in this study, is a suitable method in terms of processing efficiency and consumer acceptability of dried strawberry products.