Optimization of the Freezing-explosion Puffing Drying for Lanzhou Lily

This study aimed to solve the problem of high hardness and poor palatability of dried lily in the market and to develop the new production technology of dried Lanzhou lily. Water content after freezing,explosion puffing drying temperature,explosion puffing drying time were selected as the influencing factors and the water content,brittleness and color of dried Lanzhou lily were used as the response values. Based on one-factor-at-a-time experiments,Box-Behnken design was applied to establish the corresponding mathematical model,and the structure of Lanzhou lily before and after the freeze-pressure puffing drying were compared by scanning electron microscope. The results showed that,the effects of these three components on water content,brittleness and color of dried Lanzhou lily followed the decreasing order:Water content after freezing > explosion puffing drying temperature > explosion puffing drying time. The best processing conditions of freeze-explosion puffing drying of dried Lanzhou lily were 70% moisture content of dried raw material after freezing treatment,explosion puffing drying temperature 65℃,explosion puffing drying time 120 min. Under the optimum condition,the water content,crisp and color difference of dried Lanzhou Lily products were 4.75%,1.78,10.63,respectively. Meanwhile,appearance and taste were the best. The scanning electron microscope showed that,the effect of explosion puffing drying on its structure was small. The structure of the tissue was not wrinkled and collapsed. The lily shape was better after the freeze-explosion puffing drying,and the process would obtain the better dried Lanzhou lily products.