Improvement of the catalytic infrared drying process and quality characteristics of the dried garlic slices by ultrasound-assisted alcohol pretreatment

This paper investigated the effects of different pretreatments on the drying process and quality characteristics of catalytic infrared (CIR) dried garlic slices. Different garlic samples, including a control (un-pretreated), and samples pretreated with alcohol, alcohol-ultrasound (US + Alcohol) and water-ultrasound (US + Water) were prepared. The effect of different pretreatments on microstructure of garlic was studied. All of the pretreatments decreased the drying time by 9.09%-27.27% compared to the control, while US + Alcohol provided the highest reduction (27.27%). The possible mechanism of improvement in the dehydrating process of garlic samples was proposed. Except for allicin content, the quality characteristics of shrinkage, surface roughness, flavor, color and the microbial content of the US + Alcohol pretreated dried garlic samples were predominately better than the control, alcohol and US + Water pretreated samples. This research provides a new pretreatment technology, to efficiently give rise to a high quality CIR dried garlic products.