Design and fabrication of catalytic infrared fruit dryer to evaluate its performance in the bananas drying process

Abstract

The present research was aimed to investigate the effects of utilizing catalytic infrared (CIR) heaters and their combination with convective heat transfer (Combined method) on the drying characteristics of bananas. The CIR and combined drying of 5 mm $$ 5\ \mathrm{mm} $$ samples were conducted at various temperatures (60, 70, and 80°C). The drying kinetics, mathematical modeling, and color change in samples were investigated. The results showed that the combined method would prolong the drying process compared to the CIR drying up to 31%. Among the seven investigated thin-layer drying models, the two-term model showed the best accuracy with R 2 $$ {R}^2 $$ ranging between 0.984 and 0.998. The results showed that the drying rate had a decreasing trend by a decrease in moisture content and temperature. The color change in samples ( ∆ E $$ \Delta E $$ ) was observed in the range 15.18–33.61. The study of sample colors indicated at 70 and 80°C, the combined method could result in minor change. Practical applications Due to multiple advantages such as significant durability, ease of transportation and storage, and providing essential nutrients, dried fruits have attracted much attention over the years. This study investigates the Catalytic IR method and the combined CIR and hot air method in the drying process of bananas. According to the results, utilization of the CIR method of drying results in a significant drying time compared to conventional methods such as hot air or solar drying. Moreover, the advantages of the CIR emitters, such as lower fuel consumption and reduced emitted pollutants such as CO and NOx, could be considered a great potential to supersede the conventional drying methods. The outcomes of this study can be used to predict the drying kinetics of bananas and to opt for the best drying conditions to achieve the most desirable color quality.