Optimization of Ultrasound‐Assisted Hot‐Air Drying of Sunflower Seeds for Enhanced Drying Efficiency and Oil Quantity

Abstract

ABSTRACT Hot‐air drying of sunflower seeds, a common preservation method, often results in high energy consumption and diminished oil quality due to prolonged drying and thermal degradation. This study employs the Taguchi method to systematically investigate and identify optimal conditions for ultrasound‐assisted hot‐air drying to enhance drying kinetics, energy efficiency, and oil retention. Using a Taguchi L16 orthogonal array, the effects of drying temperature (50°C, 60°C, 70°C, and 80°C), air velocity (0.5, 0.7, 0.9, and 1.1 m/s), and sonication time (0, 4, 8, and 12 min) were investigated. Evaluated responses included total drying time, drying rate, effective moisture diffusivity, specific moisture evaporation rate (SMER), and oil content. Sonication time emerged as the most influential factor in reducing drying time and increasing drying rate by modifying seed microstructure to promote moisture migration. Drying temperature primarily affects energy efficiency and moisture diffusivity but adversely impacted oil content at elevated levels. A trade‐off was observed where high temperature increased drying efficiency but reduced oil quality, while lower temperature preserved oil at the expense of drying time. A compromise condition, identified through analysis of individual response optima, balanced these factors, enabling rapid, energy‐efficient drying with superior oil retention compared to conventional hot‐air methods. This work underscores the potential of combined ultrasonic and thermal treatments to develop sustainable drying protocols for oilseeds.