Foodstuff - Thermal Diffusivity
Thermal diffusivity of some selected food products.
Thermal diffusivity is the rate of transfer of heat of a material from the hot side to the cold side - a measure of how quickly a material can absorb heat from its surroundings. It can be calculated by taking the thermal conductivity divided by density and specific heat capacity at constant pressure.
Thermal diffusivity has the SI derived unit of (m²/s), and is usually denoted α but a, κ, K, and D are also used. The formula is:
α =k / (ρ CP) (1)
where
α = thermal diffusivity (m2/s)
k = is thermal conductivity (W/(mK))
ρ = density (kg/m³)
CP = specific heat capacity (J/(kgK))
Thermal diffusivity of selected foodstuff:
| Foodstuff | Water Content (% wt) | Temperature (oC) | Thermal Diffusivity (10-7 m2/s) |
|---|---|---|---|
| Apple, juice | 37 | 5 | 1.05 |
| Apple, whole | 85 | 0 - 30 | 1.37 |
| Avocado, flesh | 24 | 1.24 | |
| Avocado, seed | 24 | 1.29 | |
| Avocado, whole | 41 | 1.54 | |
| Banana, flesh | 76 | 5 | 1.18 |
| Beans, baked | 4 - 122 | 1.68 | |
| Beef, chuck | 66 | 40 - 65 | 1.23 |
| Beef, round | 71 | 40 - 65 | 1.33 |
| Beef, tongue | 68 | 40 - 65 | 1.32 |
| Cherries, flesh | 30 | 1.32 | |
| Codfish | 81 | 5 | 1.22 |
| Corned beef | 65 | 5 | 1.32 |
| Grapefruit, flesh | 89 | 1.27 | |
| Halibut | 76 | 40 - 65 | 1.47 |
| Ham, smoked | 64 | 5 | 1.18 |
| Lemon, whole | 72 | 40 | 1.07 |
| Lima beans, pureed | 26 - 122 | 1.80 | |
| Pea, pureed | 16 - 122 | 1.82 | |
| Peach, whole | 27 | 1.39 | |
| Potato, cooked and mashed | 78 | 5 | 1.23 |
| Potato, flesh | 25 | 1.70 | |
| Rutabaga | 48 | 1.34 | |
| Squash, whole | 47 | 1.71 | |
| Strawberry, flesh | 92 | 5 | 1.27 |
| Sugarbeet | 14 | 1.26 | |
| Tomato, pulp | 4 | 1.48 |
