Experimental Studies on Moso Bamboo Shoot Treatment by a Combination Drying of Hot-Airflow and Vacuum Freeze

Moso bamboo shoots were treated by a combination drying of hot-air and vacuum freeze in this work. Energy consumption and physicochemical properties of combination dried products were compared with those of 100% hot-air drying and 100% vacuum freeze drying processes, respectively. It showed that the favorate combined drying method was to use vacuum freeze drying first and then shifit to hot-air, drying at the point when 20% moisture content was reached. The combination dried products of vacuum freeze and hot-air were superior to hot-air dried products on appearance, nutrition, rehydration ratio and cell structure aspects and closed to that treated by vacuum freeze dried method. Furthermore, the combined drying process saved 21% energy consumption compared with the energy cost using 100% vacuum freeze drying process.