Study of Drying of κ-Carrageenan Gel at Various Temperatures Using a Fluorescence Technique

Abstract

The steady-state fluorescence technique was used to study drying of κ-carrageenan gel at various temperatures. Pyranine was doped as a fluorescence probe, and scattered light, I _sc , and fluorescence intensities, I, were monitored during drying of these gels. It was observed that I decreased linearly as drying time is increased. The moving boundary model based on Case II diffusion was applied to produce the packing constants, k ₀, at higher temperatures. Activation energy for drying was found to be 53.9 kJ mol⁻¹. Supporting gravimetric and volumetric measurements were also carried out during drying of gels and the corresponding activation energies were determined to be 46.4 and 58.9 kJ mol⁻¹, respectively.

Keywords:

• κ-Carrageenan
• Fluorescence
• Gel drying
• Moving boundary model
• Packing

Notes

d _i : Thickness of the gel before drying process.

d _∞: Thickness of the gel after drying process.

m _i : Weight of the gel before drying process.

m _∞: Weight of the gel after drying process.

a: Diameter of the gel.