Kinetics and mathematical models of date paste dried using a convective infrared dryer

Abstract

Achieving the desired level of caramelisation in a date powder requires considerable effort. Consequently, an assessment was conducted on efficacy of thin-layer infrared dehydration for date paste. Various parameters were considered, including airflow velocities of 0.5, 1.0, and 1.5 m.s-1, radiation intensities of 0.076, 0.1528, and 0.228 W.cm-2, and date paste layer thicknesses of 3 mm and 5 mm. The study's findings indicated a positive correlation between drying rate and lowering airflow velocity and a negative correlation between drying time and decreasing airflow velocity, the thickness of date paste, and rising intensity of infrared. The effective moisture diffusivity (Deff) was caculated by employing Fick's diffusion equation. For all situations under investigation, the mean values were within the range of 3.94 × 10-11 m2.s-1 to 6.01 × 10-10 m2.s-1. A relationship has been established between Deff and moisture content. Seven distinct mathematical models were subjected to rigorous validation by applying non-linear regression analysis, aiming to accurately characterise the drying process of date paste. The modified two-term model provided the most accurate forecast of the drying process for date paste layers.

Keywords

• drying rate
• convection-infrared dryer
• mathematical modeling
• effective moisture diffusivity