Abstract—The Kuala fragrant pear produced in Xinjiang Province of China is the materials of many kinds of heath food and drug. The measurement results showed that the average moisture content of fresh fragrant pear is 87%; the eutectic temperature is in the range of -17℃~-23℃ and is regarded as -20℃ averagely; the melting point is -15℃. For the fragrant pear of 4mm thick, the freeze-drying experiment were carried out as follows: the pre-freezing time is 1.5h, and the pre-freezing temperature is -35℃; the time for freeze dehydration is 7.5h, and the temperature is respectively 0℃, 10℃, 20℃; the time for desorption drying is 2h, and the temperature is 50℃. The total time is 11h. The freeze-drying process curve is given. The quality of the freeze-dried fragrant pear was tested and the result is comparatively well. By a series of experiments, the effect of freeze-drying parameters on the freeze-drying time and product quality were discussed, the parameters including the freezing rate, heating temperature, pressure of drying chamber and thickness.
Index Terms—Freeze-drying, Kuala fragrant pear, eutectic temperature, physical parameters, process optimization
S. H. ZHANG is with the of Mechanical Engineering and Automation, Northeastern University, Shenyang 110004, China. (fax: 86-24-83679926;).
Z. J. ZHANG, is with the of Mechanical Engineering and Automation, Northeastern University, Shenyang 110004, China. (phone: 86-24-83679926; fax: 86-24-83679926).
C. H. XU is with the of Mechanical Engineering and Automation, Northeastern University, Shenyang 110004, China. (fax: 86-24-83679926).
Cite : S. W. ZHANG, Z. J. ZHANG, C. H. XU and D. M. E, " Study on the Preeze-drying Experiment of Kuala Fragrant Pear Slice ," International Journal of Engineering and Technology vol. 1, no. 4, pp. 274-277, 2009.