Processing dried products is an ancient human activity that causes little scientific attention. Later, in the early of this century. Various innovations took place in food processing technologies and people started to notice the texture of dried products. Nonetheless, people continued to process the original products using only very simple drying techniques, such as natural sun light drying.

As the living standard has been lifted and convenience of the utilization. Advanced machinery and techniques have been adopted into application for these not long period years. These introductions have encouraged the rapid advancement of the dried product also the equipment industry. As can be seen, the types of dried products on the market are extremely varied. Originally, the main purpose for processing dried products was to extend the preserving time of an otherwise perishable product and to make the products taste special.

As we know, since the drying procedure lowers products' water content and the level of product water activity, the shelf life of the dried products becomes longer. The dried products can also develop special aromatic flavors during storage, since some of the proteins are altered by proteinases to produce amino acids. On the other hand, as drying foods means substantially lower transport and handling costs. Easy storage and convenient preparation make dry food popular.

Except, more and more evidence reveals that Chinese herb medicine cure chronic disease more effectively than biochemical medicine. We do believe that the Chinese herb medicine would be kept more effective through medium temperature drying processed than not appropriate high temperature.

Of course, we also know that most health food would be preserved more nutritious through low or medium temperature drying processed than inappropriate high temperature. These special flavors and other properties make dried products very attractive and have allowed them to develop their own stable base in the competitive market especially on low or medium temperature process dried products. The dried product industry is now well developed.