Bracken Vacuum Freeze Drying Technology Research

Fiddleheads ?one kind wild vegetable of Mountain chang bai was selected as the raw material of the study, then vacuum freeze drying method was adopted through the production exploration of freeze drying fiddleheads. The result of experiments indicated that the ecnomical and optimum quality freeze drying fiddleheads production could be got under the following conditions: The pressure in drying room was 20 pa ; The freezing velocity was 1.5℃/min; The loading of the machine was 2.70kg/m2~3.15; The heating temprature was 38℃~42℃. The freeze drying fiddleheads production we got under the conditions above had these physical index: The drying ratio is 14.4; The reabsorbing ratio is 13.8; The Aw is 0.588; Through experiments green-protect conditions related to the quality of freeze drying fiddleheads was given . Then the curve of freeze drying fiddleheads was got and assured the optimum processing technology of freeze drying fiddleheads production. We had maken comparation and analysis of the nutrition contents between the freeze-dried and heat-dried fiddleheads production. The quality controling and HA had be analized, and the CCP of the technology was given, and the indefinite estimating synthetic theory was used to estimate the quality of the freeze-dried fiddleheads to assure the conditions of the freeze drying processing technology , then directed the reality and production.