Cold Plasma–Assisted Drying of Canola Seeds: Effects on Drying Kinetics, Oil Yield, and Oil Quality
摘要
This study investigated the combined effects of dielectric barrier discharge (DBD) cold plasma pretreatment and fluidized bed drying on the drying kinetics of canola seeds and the yield and quality of the extracted oil. Seeds were treated with atmospheric air plasma (11 kV, 14 kHz) for 0–60 s and dried at 40–60 °C under near-minimum fluidization conditions (3 m s−1). Drying time was significantly affected by both temperature and plasma exposure (p < 0.05), with temperature exerting the greatest influence. Increasing the drying temperature from 40 to 60 °C reduced drying time by approximately 35–45%. Plasma pretreatment for 15–30 s further shortened drying time at 40–50 °C, whereas a 60 s exposure slightly prolonged drying at 60 °C. Oil yield showed a nonlinear response to the processing conditions. Moderate plasma treatment (15–30 s) at 40–50 °C increased oil yield. In contrast, drying at 60 °C reduced the amount of extractable oil. Despite processing-induced variations, the overall fatty acid composition remained stable, and the extracted oils retained favorable nutritional characteristics. Color stability was strongly affected by drying temperature. The total color difference (ΔE) remained low at 40–50 °C but increased markedly at 60 °C. Only minor changes in refractive index were observed, indicating that the overall quality and structural integrity of the oil were largely preserved. Overall, controlled plasma pretreatment improved moisture transfer and oil recovery at moderate temperatures, whereas excessive thermal–plasma intensity adversely affected oil quality, highlighting the importance of process optimization in plasma-assisted drying systems.