| Author | Onrawee Techasena |
| Call Number | AIT Thesis no. AE-82-03 |
| Subject(s) | Potatoes--Thailand--Testing
|
| Note | A thesis submitted in partial fulfilment of the requirement for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The firmness of potatoes was evaluated in terms of the elasticity modulus based on axial compression, radial compression and Hertz contact
stress analysis using an Instron testing machine. Cylindrical test specimens (1. 5 cm in diameter and 3. 0 cm long), whole potatoes and their flat surface
were tested under compression at the loading rate of 50mm/min. The changes in firmness of potatoes were monitored over a period of 8 weeks when stored
at 5, 10, 20 and 30°C.
Potatoes exhibited nonlinear force-deformation behavior in axial compression tests requiring the calculation of tangent elasticity modulus
values as a function of percent compression. In .radial compression tests, there was marked deviation of experimental force-deformation relationships from the theory. Therefore, the computed values of elasticity modulus were expressed as a function of percent compression. In compression tests with
whole potatoes and their flat surface, the force-deformation relationship conformed to Hertz analysis only at low compression values and could be used to calculate elasticity modulus independent of percent compression. The
experimental elasticity modulus values showed a wide variation in their magnitudes primarily .due to the characteristics of each test method used.
The firmness of potatoes appeared to decrease exponentially with storage
period at all temperatures. Since the elasticity modulus values .as determined in various compression tests were different, it was necessary to express change in their magnitude during storage on percentage basis for making
relative comparisons. The radial compression test showed maximum percentage
decrease in the elasticity modulus values with storage time. The axial compression test values were next. The compression of whole potatoes and their flat surface followed very closely to each other and showed minimum decrease
in the elasticity modulus values during the storage at all temperature. |
| Year | 1982 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Jindal, Vinod Kumar
; |
| Examination Committee(s) | Yudhbir ;Kim, Kong-Hwan
; |
| Scholarship Donor(s) | The US-ASEAN; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1982 |