MOISTURE DIFFUSIVITY DATA COMPILATION FOR FOODSTUFFS: EFFECT OF MATERIAL MOISTURE CONTENT AND TEMPERATURE

Figures & data

Table 1. Mathematical Model for Calculating Moisture Diffusivity as a Function of Moisture and Temperature

Effect of Moisture and Temperature on Moisture Diffusivity
Proposed Model
where D(m^2/s) the effective moisture diffusivity,
X(kg/kg db) the material moisture content,
T(°C) the material temperature,
Tr = 60°C a reference temperature, and
R = 0.0083143 kJ/kg mol K the ideal gas constant.
Adjustable Model Parameters
1. Do (m^2/s) Diffusivity at moisture X = 0 and temperature T = Tr
2. Di (m^2/s) Diffusivity at moisture X = ∞ and temperature T = Tr
3. Eo (kJ/mol) Activation Energy for diffusion in dry material at X = 0
4. Ei (kJ/mol) Activation Energy for diffusion in wet material at X = ∞

Figure 1. Parameter estimates of the proposed model of Table 1.

Figure 2. Effective moisture diffusivity of Corn Grains at various temperatures and moisture contents.

Figure 3. Effective moisture diffusivity of Apple at various temperatures and moisture contents.

Figure 4. Effective moisture diffusivity of Potato at various temperatures and moisture contents.

Figure 5. Predicted values of moisture diffusivity for fruits.

Figure 6. Predicted values of moisture diffusivity for vegetables.

Figure 7. Predicted values of moisture diffusivity for various grains.

Figure 8. Predicted values of moisture diffusivity for cereal products.

Table 2. Parameter Estimates of the Model Presented in Table 1

Material	No. of Papers	No. of Data	Di (m^2/s)	Do (m^2/s)	Ei (kJ/mol)	Eo (kJ/mol)	Sd (m^2/s)
Cereal Products
Corn
–	4	26	4.40E-09	1.00E-15	0.0	10.4	1.48E-10
dent	3	15	1.19E-08	1.00E-15	49.4	73.1	3.30E-10
grains	3	28	1.15E-09	6.66E-11	10.2	57.8	3.17E-10
kernel	4	25	5.87E-10	5.32E-10	0.0	33.8	1.88E-11
pericarp	3	13	1.13E-09	1.00E-15	10.0	5.0	2.34E-11
Pasta
–	3	21	1.39E-09	1.00E-15	16.2	2.0	7.71E-12
Rice
kernel	3	12	9.75E-09	1.00E-15	12.5	2.0	5.52E-11
Rough Rice
–	7	35	2.27E-09	1.00E-15	12.7	0.7	3.66E-11
Wheat
–	6	22	1.94E-09	1.30E-09	0.0	46.3	9.53E-11
Fruits
Apple
–	8	39	7.97E-10	1.16E-10	16.7	56.6	1.92E-10
Banana
–	4	34	2.03E-09	4.66E-10	9.9	4.6	1.77E-10
Grapes
seedless	3	32	5.35E-09	1.00E-15	34.0	10.4	1.45E-10
Raisins
–	3	10	8.11E-10	1.05E-10	21.4	50.1	6.88E-11
Model Foods
Amioca
–	4	49	1.52E-08	1.52E-08	0.0	33.3	1.02E-09
Hylon-7
–	5	48	1.96E-08	1.96E-08	0.0	24.2	3.87E-09
Vegetables
Carrot
–	9	90	2.47E-09	1.54E-09	13.9	11.3	1.69E-09
Garlic
–	4	22	5.33E-10	1.68E-11	15.4	7.1	7.43E-11
Onion
–	4	31	1.45E-08	1.00E-15	70.2	10.4	1.58E-09
Potato
–	16	106	1.57E-09	4.31E-10	44.7	76.9	4.02E-10