Abstract
Complex impedance was measured to analyze freezing-injury for food materials. High impedance and distinct Cole-Cole arc were observed for fresh plant cell tissue samples such as Japanese radish, carrot, potato, and apple. After freezing-thawing, however, impedance drastically decreased and the Cole-Cole arc disappeared reflecting the severe freezing-injury on plasma membrane. On the contrary, animal cell tissue samples like poultry and fish meat showed much lower impedance, which did not change much after freezing-thawing reflecting the stronger freezing tolerance for these samples. No distinct Cole-Cole arc was observed for these samples suggesting the different cell structure of animal tissue as compared with plant tissue. For gel-type sample like soyprotein gel, impedance rather increased after freezing-thawing.
