CHARACTERISTICS OF CHAMBER TEMPERATURE CHANGE DURING VACUUM COOLING
In order to investigate the dynamic changing pattern of the chamber temperature with chamber pressure during vacuum cooling, 10 repeated experiments were conducted to evaluate the time-dependent temperature and pressure in the vacuum chamber during vacuum cooling of water. Water was chosen in the experiment as it is the main component of most foods. The results showed that the temperature in the vacuum chamber significantly depended on variation in pressure at different pumping stages. The temperature changes in the chamber generally followed a certain pattern. In the early stage of vacuum cooling, the chamber temperature dropped very quickly (0.26 K/s), while at the end of vacuum cooling, it increased rapidly (0.22 K/s), and was about 11.8 K higher than the ambient temperature when the vacuum was released with ambient air flowing back to the chamber. PRACTICAL APPLICATIONS
Vacuum cooling is a rapid cooling method for the food industry; further understanding of the vacuum cooling mechanism can help to control and improve this cooling process. Temperature changing pattern and distribution affects the quality of the food product in vacuum cooling process. As the main component of most foods is water, it is necessary to investigate the dynamic temperature changing pattern and distribution with vacuum pressure during vacuum cooling of water so that the information obtained could be used as a reference for vacuum cooling of food products.
Document Type: Research Article
Affiliations: Institute of Cryobiology and Food FreezingShanghai University of Science and TechnologyShanghai, China
Publication date: April 1, 2009