Polytechnic University of Valencia Congress, 21st International Drying Symposium

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Observation of microstructure change during freeze-drying by in-situ X-ray Computed Tomography
Kyuya Nakagawa, Shinri Tamiya, Shu Sakamoto, Gabsoo Do, Shinji Kono, Takaaki Ochiai

Last modified: 02-01-2019

Abstract


X-ray computed tomography technique was used to observe microstructure formation during freeze-drying. A specially designed vacuum freeze-drying stage was equipped at the X-ray CT stage, and the frozen and dried microstructures of dextrin solutions were successfully observed. It was confirmed that the many parts of the pore microstructures formed as a replica of the original ice microstructures, whereas some parts formed as a consequence of the dehydration dependent on the relaxation level of the glassy phases, suggesting that the post-freezing annealing is advantageous for avoiding quality loss that relates to the structural deformation of glassy matters.

Keywords: freeze-drying; X-ray CT; ice microstructure; glassy state

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