Optimization of Superheated Steam Combined Vacuum Drying Technology of Bamboo Shoots by Response Surface Method

This paper discussed the effect of superheated steam temperature,conversion time and vacuum drying temperature on rehydration ratio and color L^* of dried bamboo shoot products by superheated steam combined vacuum drying method. The influence and interaction of superheated steam temperature,conversion time and vacuum temperature on the quality of dried bamboo shoots were analyzed and the combined drying process was optimized by central combination test design. The results showed that,the optimum combined drying conditions were 119℃ of the superheated steam temperature,35 min of conversion time and 74℃ of vacuum temperature. Under these conditions,the drying rate and quality were better,the rehydration ratio of bamboo shoots was 6.23 and the color parameter L^* value was 92.83.Compared with hot air drying,it saved 56.25% of time and 52.65% of energy. The results showed that superheated steam combined vacuum drying method can achieve rapid drying of bamboo shoots,it is more energy-saving,efficient and has better quality of products than hot air drying.