食品过热蒸汽撞击干燥的试验研究

研究了过热蒸汽撞击干燥过程中蒸汽温度和传热系数对样品的降水速度，温度场和干燥品质的影响规律，发现在研究的参数范围内，蒸汽的影响比传热系数显著。通过与热风撞击干燥的对比试验，发现过热蒸汽撞击干燥后样品淀粉糊化度明显高于热风撞击干燥，当介质温度高于３９３Ｋ时，过热蒸汽撞击干燥的干燥速度高于热风撞击干燥。

SUPERHEATED STEAM IMPINGEMENT DRYING OF FOOD

Superheated steam impingement drying of foods has the advantage of improved energy efficiency and product quality. The temperature profile, drying curves, and the physical properties (gelatinization and microstructure) of tortilla chips dried at different superheated steam temperature and heat transfer coefficient were experimentally evaluated. The results indicate that the steam temperature has a greater effect on the drying curve than the heat transfer coefficient. The difference between the superheated steam drying and air drying was also analyzed. The drying rate of the superheated steam drying is higher than the heated air drying when the agent temperature higher than 393 K. The microstructure of the samples after air drying appears to be more porous and coarser. The pasting properties of dried samples show that products dried under superheated steam gelatinized more readily with improved ability to absorb water.