采用干燥方法可将食品脱水进行长期保存。热风干燥不适合热敏性食品,且干燥后产品品质较差,而采用冷冻干燥,虽能克服上述缺点,但干燥时间长,效率低。文中提出一种冰温干燥新技术,以胡萝卜为实验原料进行了冰温干燥实验研究,并与真空冷冻干燥及热风干燥进行了对比。实验结果表明:在150 Pa的压力下,经过4 h冰温干燥,得到的胡萝卜含水率为4.8%,其复水性优于热风干燥,其干燥样品中的Vc及胡萝卜素等营养成分损失少,外观色泽优良,干燥时间比冷冻干燥显著减少。

Drying method is used for dehydrating food for long-term preservation.Hot-air drying is not suitable for drying heat-sensitive food,and the product qualities is poor;vacuum freeze-drying is able to overcome these disadvantages,but to much time and low efficiency.This paper provides a new drying technology,controlled freezing-point drying.Taken carrot as the experimental material,the controlled freezing-point dried processing is studied.The result was compared with the vacuum freeze-drying and hot-air drying.The result were : at the pressure of 150 Pa,after 4 hours of drying,water content of carrot was 4.8%.The results also showed that rehydration was better,Vc and carotene in carrots were merely lost,the carrots kept nice color and appearance.Compared with freeze-drying,drying time significantly reduced.