Dehydration of Garlic Slices by Combined Microwave-Vacuum and Air Drying

Abstract

Combination of microwave-vacuum drying and air drying was investigated as a potential mean for drying garlic slices. The sample was dried by microwave-vacuum until the moisture content reached 10% (wet basis), and then by conventional hot-air drying at the temperature of 45°C to final moisture content less than 5% (wet basis). Pungency, color, texture, and rehydration ratio of garlic slices dried by this method were evaluated and compared with those dried by freeze drying and conventional hot-air drying. The comparison showed that the quality of garlic slices dried by the current method was close to that of freeze dried garlic slices and much better than that of conventional hot-air dried ones. The lab microwave-vacuum dryer which the materials to be dried could be rotated in the cavity was developed by the authors.

Keywords:

• Garlic slice
• Allicin
• Allinase
• Pungency
• Microwave-vacuum drying
• Freeze drying
• Conventional hot-air drying

Acknowledgments

The authors wish to thank Mr. Quan-Jin Bian, the general engineer of Wuxi Ketakaseiko Electrical Appliance Co. Ltd., and Mr. Mei Cheng, the general engineer of Nanjing Sanle Microwave Technology Development Co. Ltd. for their practical assistance in this project.