Relationship between the electrical and rheological properties of potato tuber tissue after various forms of processing
Author
Summary, in English
The impedance at frequencies of 1-1000 kHz and dynamic bending storage modulus measured by the vibrating reed method were compared for potato tuber tissue, which had been processed by various methods. Raw potato tuber tissue strips were either heated for 30 min up to 100°C or frozen-thawed. Some samples were osmotically dehydrated in a mannitol solution up to a concentration of 0.7 mol/l. The electrical reactance correlated well with the storage modulus of heated or frozen-thawed potato tissues, but not with the storage modulus of the mannitol-treated tissue. The storage modulus appeared to be strongly dependent on the turgor pressure of the cells which was drastically decreased by the heating, freezing-thawing, and osmotic treatments. The electrical properties reflect the cell integrity, and a large difference was observed between the change in impedance after heating or freezing-thawing, and that after the osmotic treatment. A significant change in the electric properties was also observed for a starch suspension at the gelatinization temperature. However, the contribution due to gelatinization did not appear to play an important role in the change of electrical properties of potato tissue by heating.
Department/s
- Department of Food Technology, Engineering and Nutrition
Publishing year
2002
Language
English
Pages
1218-1223
Publication/Series
Bioscience, Biotechnology and Biochemistry
Volume
66
Issue
6
Document type
Journal article
Publisher
Oxford University Press
Topic
- Food Engineering
Keywords
- impedance
- storage modulus
- vibrating reed
- heat processing
- osmotic dehydration
Status
Published
ISBN/ISSN/Other
- ISSN: 1347-6947