Temperature variation on Shanghaiqing surface during vacuum cooling process

Based on the characteristic of internal water passages of leafy vegetable, the disciplinarian of temperature variation of “Shanghaiqing” surface during the vacuum cooling process was studied. The temperature near main vein and the one near fine vein both dropped continuously during the vacuum process, while the one around the margin may rise after a fall. Temperature difference between main vein and fine nein and that between fine vein and the margin of leaves, both existed all the time and increased firstly and then decreased. With the increment of final pressure, the final temperature in margin increased, whereas the ones near the main vein and near the fine vein both decreased first and then increased, so the final pressure shouldn’t be set too low.