Experimental trials on the vacuum precooling of various vegetable and fruit products

Pasqualone, S. B.

Vacuum cooling is based on the loss of heat by evaporation of a small amount of moisture from the product under low pressure. Best results are obtained at 4.6 mm mercury (which corresponds to a boiling temperature of 0 degrees C); superficial freezing will occur at lower pressures. The system used in the trials consisted of a low pressure treatment chamber, a gas extractor unit, a vapour condensation apparatus, and an electronic control panel.