Determination of the Effective Moisture Diffusivity Coefficient and Mathematical Modeling of Balangu Seed Gum Drying with Infrared

Today, drying of agricultural products is a developed method that removes part of the moisture leads to physicochemical stability of the product, also, produces different products with new qualitative properties and different nutritional and economical value. Moisture diffusivity coefficient is the most crucial property in drying calculations.

In this study, drying kinetics modeling of Balangu seed gum in an infrared dryer was investigated. The effect of samples distance from the radiation lamp in three levels of 5, 7.5 and 10 cm and the effect of gum height in the container in three levels of 0.5, 1.0 and 1.5 cm on the mass transfer rate and effective moisture diffusivity coefficient during the dry process of Balangu seed gum was investigated. Standard models (Wang and Singh, Henderson and Pabis, Approximation of diffusion, Page, Modified Page, Newton, Midilli, and Logarithmic) were fitted to experimental data to study the drying kinetics and was analyzed.

The results showed that samples distance from the radiation lamp and samples thickness had significant effect on the mass transfer rate during drying of gum. By increasing samples distance from the heat source from 5 to 7.5 cm and from 7.5 to 10 cm, the drying time of Balangu seed gum increased by 21.49% and 15.20%, respectively. The effect of sample distance from infrared heat lamp and sample thickness on changes in effective moisture diffusivity coefficient of Balangu seed gum was investigated and results showed that this coefficient values were increased with decreasing in distance and increasing samples thickness. By reducing sample distance from the lamp from 10 to 5 cm, it was observed that the effective moisture diffusivity coefficient increased from 4.82×10-9 m2s-1 to 7.05×10-9 m2s-1.

In drying process modeling of Balangu seed gum, the Page model with the highest coefficient of determination and the lowest error, had closer results to the experimental data than the other models.