The main purpose of this thesis is to develop a model that can predict the temperature profile inside a frozen food sample during microwave tempering and infrared assisted microwave tempering processes. Another goal of the study is to compare the tempering time of frozen foods by using microwave, infrared assisted microwave, and ohmic heating methods. Frozen potato puree was used as the food sample for all studies.
Three different microwave power levels (30%, 40%, and 50%) were used for microwave tempering studies. Three different microwave power levels (30%, 40%, and 50%) and three different infrared power levels (10%, 20%, and 30%) were
combined for infrared assisted microwave tempering. As a control, tempering was done by keeping the sample at 4° / C. The increase in microwave power level and infrared power level reduced tempering time in infrared assisted microwave
tempering. For the ohmic tempering studies, three different frequencies (10 kHz, 20 kHz, and 30 kHz) and three different salt contents (0.50%, 0.75%, and 1.00%) were used. The increase in frequency of ohmic heating and salt content also decreased tempering times. Microwave tempering and infrared assisted microwave tempering of frozen foods were simulated by using finite difference method. For this purpose, the change
in heat capacity and the dielectric properties of frozen potato puree with respect to time were measured. The temperature distribution inside the sample was modeled, and the predicted results were compared with experimental results. The predicted
temperatures showed good agreement with the experimental data (r2 > / 0.985). It was possible to decrease tempering times by about 75%, 90%, and 95% using ohmic, microwave, and infrared assisted microwave tempering methods, respectively as
compared to control.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12609666/index.pdf |
| Date | 01 June 2008 |
| Creators | Seyhun, Nadide |
| Contributors | Sumnu, Gulum |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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