Sublimation dryer STH-50 designed and manufactured at Department of Storage and processing Equipment, Faculty of Engineering, Hanoi University of Agriculture, is used for drying products being sensitive to temperature such as vegetable, fruit, meat, fish, medicinal herb, enzyme, etc. This is a discontinued system with two dephasingfrozen condensers (one condenser is in condense-freezing phase while the other one is in deicing phase and inverse). Drying product is extra-fast frozen by nitrogen liquid and de-iced by thermal energy from heater behind refrigerant compressor, therefore it can increase product quality, and reduce drying time and specific energy consumption for drying process. Results of singlejactor experiment when dry red membrane of Gac fruit seed determined affection degree and varying trend of factors such as freezing temperature Tlv (oC), radiation temperature Tbx (oC) and layer deep of drying product S (mm) to carotenoid content Ct (mg/ 100g), vitamin E content Ve( mg/l 00g), drying time t(h), specific energy consumption Nr (k Wh/kg SPK), and selected appropriate research range for factors as the base for multi-factor experimental research such as freezing temperature -30 to -38oC, radiation temperature 24 + 40oC, thickness of drying product layer 5 + 25mm.