GRAVIMETRIC MEASUREMENT OF MOISTURE SORPTION ISOTHERM AND ISOSTERIC HEAT OF BLACK PEPPER

Yutthana  Tirawanichakul; Sae-Khow  Atchara; Supawan  Tirawanichakul

Authors

Yutthana Tirawanichakul Plasma and Energy Technology Research Laboratory, Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
Sae-Khow Atchara Department of Chemical Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
Supawan Tirawanichakul Department of Chemical Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.

Keywords:

Equilibrium moisture content, isosteric heat of sorption, sorption isotherm, thermo-physical properties

Abstract

There are 4 objectives of Thailand 4.0 economic model, and 1 of the objectives is economic prosperity for creating a value-based economy, especially on agricultural sector. Thus, the principal physical, biological, chemical and physico-chemical properties data for each agriculture products and food should be studied and reported on for overall collection of agricultural product data. So, the main objectives of this work are to evaluate some thermo-physical properties of black pepper and to develop mathematical model of sorption isotherm for black pepper. Therefore, the thermo-physical properties in terms of equilibrium moisture content (EMC), apparent density (p), void fraction (ε) and specific heat capacity (cp) were determined in this research. In addition, the drying kinetics of black pepper was also studied and predicted by mathematical modeling. The EMC simulation results showed that the predicted data using the modified Halsey model gave the best fit to the exact desorption isotherms data of black pepper, providing the highest coefficient of determination (R2 = 0.98) and the lowest root mean square error value (RMSE = 0.68). To determine 3 thermo-physical properties, the results stated that the apparent density, the percentage of the void fraction, and the specific heat capacity value of black pepper were linearly dependent upon moisture content.

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