Utilizing The Vacuum Freeze-drying Technique To Manufacture The Dried Flowers Of 4 Kinds Of Flowers

As a unique form of ornamental, dried flower is beautifying the people's living from varied facets and being increasingly appreciated. The dried flower that is manufactured with vacuum freeze-drying technique has unmatched qualities. Whereas the application of vacuum freeze-drying technique to making dried flower is hardly wide-ranging and the study on this aspect is few. In this thesis, the systemically experimental studies had been performed with Centaurea cyanus L.,Helianthus tuberosus L.,Dendranthema×cyanus Tzvel. and Gerbera jamesonii Bolus, using vacuum freeze-drying technique. Through the experiments and analyses, the master parameters were determined during the freeze-drying processes and the optimal vacuum freeze-drying technologies of 4 kinds of testing flowers were optimized. The cellulose content of 4 kinds testing flowers' petals were determined and the relation between the cellulose content of testing petals and the changes of their shapes after drying was analyzed. The main results were represented as follows:(1) The optimal vacuum freeze-drying technology of Centaurea cyanus L.: selecting blooming flowers, freezing in a -80 ℃ icebox for 19 min and vacuum drying for 18h in the vacuum freeze-drying machine.(2) The optimal vacuum freeze-drying technology of Helianthus tuberosus L.: freezing in a -80℃ icebox for 19 min, inserting into flowermud and vacuum drying for 18h in the vacuum freeze-drying machine.(3) The optimal vacuum freeze-drying technology of Dendranthema×cyanus Tzvel.: freezing in a -80℃ icebox for 40 min, laying upside-down and vacuum drying for 36h in the vacuum freeze-drying machine.(4) The optimal vacuum freeze-drying technology of Gerbera jamesonii Bolus: freezing in a -80℃ icebox for 43 min, inserting into flowermud and vacuum drying for 27h in the vacuum freeze-drying machine. The dried petals of Gerbera jamesonii Bolus are breakable and the better means to make them flexile is steeping in 20% glycerin for 8h.(5) The relation between the cellulose content of testing petals and the changes of their shapes after drying was contrary. The cellulose content testing petals is higher than others, then the changes of their shapes after drying is fewer than others and vice versa.