The effect of natural convection air temperature on the drying kinetics and desorption isotherms of Alaria esculenta and Palmaria palmata

Abstract

The Northern Periphery and Arctic region faces unique economic and food security challenges that may be partly answered by commercial seaweed production. Alaria esculenta and Palmaria palmata are two seaweeds commonly found in the region and suitable for cultivation and processing for food and other commercial products. The drying kinetics for both species were obtained, and the Page and Weibull models best described the data. A drying air temperature increase from 40 to 70°C decreased drying time by 62.4% and 61.7% for A. esculenta and P. palmata, respectively. Desorption isotherms were obtained between 25 and 70°C and showed Brunauer Category III shapes, with water activity increasing with temperature for a fixed moisture content. Net heats of desorption were obtained, with drying to an equilibrium moisture content of 0.01 kgwater kgd.b.–1 requiring 18.1 and 3.94 kJ mol–1 K–1 for A. esculenta and P. palmata, respectively.

Keywords

• convective blown air drying
• desorption isotherms
• drying kinetics
• heat of sorption