| Project/Area Number |
07660155
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
食品科学・栄養科学
|
|---|
| Research Institution | Tokyo University of Fisheries |
|---|
Principal Investigator |
SAKAI Noboru Tokyo University of Fisheries, Department of Food Science and Technology, Asociate Professor, 水産学部, 講師 (20134009)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HANZAWA Tamotsu Tokyo University of Fisheries, Department of Food Science and Technology, Profes, 水産学部, 教授 (10008451)
|
|---|
| Project Period (FY) |
1995 – 1996
|
| Project Status |
Completed (Fiscal Year 1996)
|
| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,400,000 (Direct Cost: ¥1,400,000)
|
|---|
| Keywords | far-infrared heating / thawing / tuna / apparent specific heat model / infinite element method |
|---|
| Research Abstract |
(1) Experiment
Frozen tuna was used as a sample. The sample was placed in a constant temperature box, in which fans were set inside to control an air flow rate, and was heated by a ceramic heater placed above the box. The temperature distribution was measured by using thermocouples and was recorded on a floppy disk.
(2) Mathematical model
An apparent specific heat model was introduced to predict two dimensional and three dimensional heat transfer in frozen food. A finite element method was applied to solve the fundamental equation and boundary conditions. Thermal properties (apparent specific heat, density, thermal conductivity) were estimated by Hakawa's empirical equations.
(3) Experimental and numerical calculation results
We performed some numerical calculations to examine the influence of the heater temperature, the ambient temperature of the sample and the sample thickness on thawing rate. Experiments were carried out to check the validity of the mathematical model. Temperature distributions in samples were measured by using thermocouples and they agreed well with the theoretical predictions.
During these experiments, deterioration, which was caused by drip loss or discoloration of the red muscles of tuna, was occurred because the surface temperature of the sample increased to unacceptable levels. However, we demonstrated that frozen tuna could be thawed without drip loss and discoloration by keeping the surface temperature below 10ﾟC.This was performed by irradiation of the energy intermittently or by reducing the heater temperature when the surface temperature reached 7ﾟC.
|
