Effects of different ultrasound treatments on microwave vacuum drying characteristics, Weibull model fitting, and drying quality of garlic (Allium sativum L.) slices

Ultrasound pretreatment power (0–200 W), temperature (20–35 °C), and time (10–40 min) were systematically examined for their effects on the drying behavior and product quality of fresh garlic slices during microwave vacuum drying (MVD). The Weibull model was employed to fit the drying kinetics. The results showed that ultrasound-assisted MVD effectively enhanced both drying rate and product quality. The drying time to reach safe moisture content at 150 W was reduced by 30.77% compared with the control. The Weibull model showed high fitting accuracy ( R 2 ≥ 0.995). The scale parameter α first decreased and then slightly increased with increasing ultrasound power and temperature, whereas the shape parameter β remained relatively stable, ranging from 1.448 to 1.649. The relatively stable β indicates that ultrasound treatment had little apparent effect on the overall moisture-removal kinetics during the MVD of garlic slices, without implying a specific moisture migration mechanism. The rehydration ratio first increased and then decreased with increasing ultrasound power and temperature, whereas the allicin content first decreased and then increased with increasing ultrasound power. The color difference Δ E first decreased and then increased with prolonged ultrasound time. The hardness increased with increasing ultrasound power but first decreased and then increased with increasing ultrasound temperature and time. Suitable ultrasound treatment improved the microstructure and promoted flavor retention. The preferred ultrasound conditions were identified as 150 W, 30 °C, and 20 min, with a comprehensive score of 0.908. This study provides a valuable theoretical reference for high-quality drying and drying-time reduction of garlic.