Numerical simulation and experimental investigation of foam-mat drying for producing banana powder as influenced by foam thickness

Abstract

The high surface-to-volume ratio and porosity of foam during foam-mat drying shorten the drying process and improve dried powder quality. Therefore, foam-mat drying has caught the attention of researchers as an effective method in sticky, heat sensitive, and viscous food biomaterials that are not easy to dry with other techniques. This research sought to explore the impact of different foam thicknesses, i.e., 3, 5, and 7 mm, on quantitative and qualitative features of unripe banana powder both experimentally and numerically. An increase in foam thickness enhanced the effective moisture diffusion coefficient by 64.69% and decreased the drying rate by 52.63%. The increase also lowered powder flowability, browning index, and total color difference. According to field-emission scanning electron microscopy, an increase in the foam thickness increased the shrinkage and stickiness of the powders. The thermal response of the powders examined by differential scanning calorimetry demonstrated maximizing the glass transition temperature at 59.75 ˚C with foam thickness of 5 mm. Comparing simulated and experimental data showed a 0.880 correlation coefficient, which confirmed the consistency between experiments and simulations. Results of this study may be used in industrial applications to design a foam-mat drying process for producing quality powder biomaterials.

Keywords

• Glass transition temperature
• Heat transfer
• Mass transfer
• Simulation