INFRARED RADIATION AND ULTRASOUND FOR SUNFLOWER SEED DRYING: EVIDENCE SYNTHESIS AND AN UNMET OPPORTUNITY FOR HYBRID PROCESSING

Abstract

Drying is a critical postharvest operation for sunflower seeds because excessive temperature and long exposure times can reduce seed quality, while insufficient drying compromises storage stability. Recent studies suggest that ultrasound-assisted convective drying (US-CD) and infrared drying with vibration (IR-V) can intensify heat and mass transfer relative to conventional hot-air approaches. In the most directly relevant sunflower-seed study on US-CD, airborne ultrasound increased effective moisture diffusivity by up to 44.84% and reduced drying time and energy consumption by up to 40.85% and 32.95%, respectively; the optimized condition shifted from a purely convective optimum of 50.74 °C, 2 m/s to 40.64 °C, 2 m/s, 3.932 W/g ultrasound [1].
A separate IR-V engineering study reported an optimized regime for sunflower seeds using 1.5–3.0 μm IR wavelength, 15 mm bed depth, and 5 kW/m² incident heat-flux density with emitters positioned 25 mm above the layer, achieving a reported drying time of ~11 min [2]. Across the screened literature, no peer-reviewed study was identified that simultaneously applies IR and ultrasound to sunflower seeds, despite the fact that ultrasound–infrared coupling has been explored in other plant materials, suggesting a plausible (but untested) synergy for oilseeds [10].