The study took banana as the research object to achieve precise thermal control of freeze-drying process and improve the quality of freeze-dried products. Specifically

the effects of pressure (10

30

50 Pa) and freeze-drying temperature (﹣20

﹣30 ℃) on effective thermal conductivity in the complete banana freeze-drying process were investigated based on the model of steady state heat flux. The sublimation process inside the banana was observed and analyzed by micro-CT scanning

and the relationship between porosity and effective thermal conductivity was also discussed. The results indicate that the effective thermal conductivity increases from 0.036 W/(m?K) to 0.072 W/(m?K) with the increase in the pressure from 10 Pa to 50 Pa. Additionally

the primary drying temperature increases from ﹣30 ℃ to ﹣20 ℃

and the corresponding effective thermal conductivity decreases from 0.084 W/(m?K) to 0.058 W/(m?K). During the freeze-drying process (30 Pa

﹣20 ℃)

the sublimation interface gradually moves to the center of the banana dice

the porosity increases from 0.059 to 0.252

and the corresponding effective thermal conductivity decreases from 0.695 W/(m?K) to 0.123 W/(m?K).