Feasibility of a gelatin temperature sensor based on electrical capacitance

Abstract

The innovative use of gelatin as a temperature sensor based on capacitance was studied at a temperature range normally used for meat cooking (20-80oC). Interdigital electrodes coated by gelatin solution and two sensors of different thicknesses (38 and 125μm) were studied between 300 MHz and 900 MHz. At 38 μm, the capacitance was adequately measured, but for 125 μm the slope capacitance versus temperature curve decreased before 900 MHz due to the electrothermal breakdown between 60oC and 80oC. Thus, for 125 μm, the capacitance was studied applying 600 MHz. Sensitivity at 38 _m at 868 MHz (0.045 pF/oC) was lower than 125 μm at 600 MHz (0.14 pF/oC), influencing the results in the simulation (temperature range versus time) of meat cooking, at 125 μm, the sensitivity was greater, mainly during chilling steps. The potential of gelatin as a temperature sensor was demonstrated, and a balance between thickness and frequency should be considered to increase the sensitivity.