Effects of Airborne Ultrasound Pretreatment on Drying Behavior, Surface Topography, and Bioactive Properties of Kiwi Slices

ABSTRACT In the present study, the effects of airborne ultrasound (ABUS) pretreatments on the drying time ( t ), effective diffusivity ( D eff ), total phenolic content (TPC), antioxidant activity (AntiO), and surface topography properties (AFM) of kiwi slices were investigated. Samples were subjected to ABUS pretreatment at different frequencies (20, 40, and 60 kHz) and power levels (400, 1100, and 2200 W) for 10 min prior to convective drying (60°C and 1.5 m/s). ABUS pretreatments significantly reduced drying time up to 29.3% compared to the control, and the shortest times were obtained at 20, 40, and 60 kHz with 400 W ( p < 0.05). Significant increases in D eff were also observed in ABUS‐treated samples ( p < 0.05). The highest TPC retention (57.8%) was achieved at 20 kHz to 2200 W and 60 kHz to 400 W ( p < 0.05), while AntiO was best preserved (up to 87.4%) under 20 (1100 and 2200 W) and 40 kHz (400 W) conditions ( p < 0.05). Atomic force microscopy revealed that ABUS treatment resulted in significant changes in surface morphology ( p < 0.05). Furthermore, correlation analysis showed a significant relationship between D eff and the average maximum depth obtained from AFM measurements. Overall, these results highlighted the significant effects of short‐time ABUS pretreatment on convective drying processes and the importance of ABUS frequency and power levels.