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Thin-layer drying characteristics of sweet potato slices and mathematical modelling


The effect of blanching and drying temperature (50, 60 and 70°C) on drying kinetics and rehydration ratio of sweet potatoes was investigated. It was observed that both the drying temperature and blanching affected the drying time and rehydration ratio. The logarithmic model showed the best fit to experimental drying data. The values of effective moisture diffusivity and activation energy ranged from 9.32 × 10−11 to 1.75 × 10−10 m2/s, and 22.7–23.2 kJ/mol, respectively.

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a, b, c:

Drying coefficients

Deff :

Effective moisture diffusivity (m2/s)

g, h, k, k0, k1 :

Drying constants (1/min)

MRexp,i :

Experimental moisture ratio

MRpre,i :

Predicted moisture ratio

Me :

Equilibrium moisture content (kg water/kg dry matter)

M0 :

Initial moisture content (kg water/kg dry matter)

Mt :

Moisture content at any time of drying (kg water/kg dry matter)

Mt+dt :

Moisture content at t + dt (kg water/kg dry matter)


Number of observations


Constant, positive integer


Mean relative percent error


The universal gas constant (kJ/mol K)

R2 :

Determination of coefficient


Root mean square error


Drying time (min)


Number of coefficients and constants

χ 2 :

Reduced Chi-square


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Correspondence to İbrahim Doymaz.

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Doymaz, İ. Thin-layer drying characteristics of sweet potato slices and mathematical modelling. Heat Mass Transfer 47, 277–285 (2011).

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  • Root Mean Square Error
  • Sweet Potato
  • Equilibrium Moisture Content
  • Initial Moisture Content
  • Moisture Ratio