APPLICATION OF CORRELATION BETWEEN BIOT AND DINCER NUMBERS FOR DETERMINING MOISTURE TRANSFER DURING THE AIR DRYING OF COROBA SLICES
Special Symposium - Innovations in Food Technology (LMC Congress)
Modern Analysis: Chemical & Multivariate Analysis (Food-6b)
Keywords: Bi-Di correlation, air drying, coroba slices
Application of the correlation between Biot (Bi) and Dincet (Di) numbers for determining the mass transfer parameters during the air drying of coroba slices was investigated. The fruit of coroba palm was peeled and the pulp cut into slices with an average thickness of 1.86 x10-3 m. The coroba slices were put in drying tray and dried in cabinet air dryer operated at air velocity of 0.82, 1.00 or 1.18 m/s and temperature 71, 82 or 93 ºC with drying from the top surface of the drying slices. Changes in weight of slices were monitored at 3 min intervals for drying time to equilibrium. The moisture content data at the different drying conditions were converted to the dimensionless moisture content. Linear regression was used to fit experimental dimensionless moisture content data to Dincer and Dot model. The high coefficients of determination (R2 > 0.97), and no pattern evident with the residuals across the range of coefficients indicated the goodness of fit of experimental data to Dincer and Dot model. Drying constant (S), lag factor (G) and Di number were determined at different drying conditions and incorporated into the Bi-Di correlation. Values of G and S ranged from 1.022 to 1.294 1.249 and from 2.892 x 10-4 to 4.189 x 10-4 s-1, respectively. The Bi numbers were in the range 0.100-0.114, indicating that during coroba slices drying an internal and external resistance to the mass transfer existed. Using values of S and Bi, the moisture diffusion (D) and moisture transfer (k) coefficients were calculated. The values of D and k ranged from 2.68 x 10-12 to 4.53 x 10-12 m2/s and from 0.903 x10-4 to 1.570 x10-4 m/s, respectively. The predicted dimensionless moisture content profiles were calculated. The mean relative error between experimental and predicted profiles ranging from 8.72 to15.02% showed that the Bi-Di correlation could be applied for determining the mass transfer parameters during air drying of coroba slices at studied conditions.
Presented Thursday 20, 10:25 to 10:30, in session Modern Analysis: Chemical & Multivariate Analysis (Food-6b).
