Effect of pressure fluctuation on vacuum cooling performance of cabbage

Pressure fluctuations in different ranges were selected in the cabbage vacuum cooling processing to improve pre-cooling effect of fruits and vegetables with the compact structure, and the changes of temperature were analyzed, and the effect of pressure fluctuation on cooling performance was compared. It was found that it needed 17.95, 24.63 and 29.55 min when the surface temperature reached 2.50℃ and the center temperature reached 8.50, 2.99 and 3.26℃ respectively with pressure fluctuation in different ranges of 560, 660Pa, 610, 710Pa and 660, 760Pa. The results show that the pressure fluctuation of 610, 710Pa is the most effective pressure range during cabbage vacuum cooling. The change of temperature from the face to the center is non-linear and pressure fluctuation is an effective method to make the temperature even in the food during the vacuum cooling.