## 1 Introduction
According to the results, the optimal condition comprised air temperature at 60 \({}^{\circ}\)C, radiation intensity at 0.30 W/cm\({}^{2}\), and air velocity at 0.5 m/s. A solar hot air dryer with infrared lamps for drying the mint and apple slices was studied [19]. The use of infrared waves, although it caused a drop in the energy efficiency of the system and increased the energy consumption, supported the system well when the sunlight was insufficient and prevented the destruction of the product. The drying kinetics and energy parameters for drying apple slices in a hot air-infrared dryer was investigated [20]. In that research, three temperature levels (90, 120, and 150 \({}^{\circ}\)C) and three infrared intensity levels (0.22, 0.31, and 0.49 W/cm\({}^{2}\)) were used. The results showed that the specific energy consumption in the infrared dryer was lower (82-86%) than in the convective dryer. In another study, the effect of air temperature (40, 50, and 60 \({}^{\circ}\)C) and infrared radiation intensity (1000, 2000, and 3000 W/m\({}^{2}\)), as well as bed condition (fixed bed and vibrating bed), on the drying kinetics of a combined dryer were investigated. The results showed that the Page model described the drying behavior better than the other thin layer models, and the effective moisture diffusion coefficient for the fixed bed state was 0.64-4.64 \(\times\) 10\({}^{-8}\) m\({}^{2}\)/s, and, for the vibrating bed, it was in the range of 0.8-5.53 \(\times\) 10\({}^{-8}\) m\({}^{2}\)/s [21]. Another problem that convection dryers have is the low quality of the dried product due to the long drying process. Using a combined dryer and increasing the temperature reduces the drying time, but the quality characteristics of the final product are not very predictable. On the other hand, an increase in temperature causes heat-sensitive compounds in the product to be lost, compounds whose presence is very beneficial for human health. The review of past research showed that, in the drying process with a hot air method, the amount of this loss is high, and it has been attempted to reduce the amount of bioactive compounds loss by performing new drying methods. In research on the effect of microwave pretreatment on convective drying of carrots, it showed that the amount of total phenolic content at the end of the process increased by about 35% compared to convective drying [22]. In research, the effects of pulsed electric field and air temperature on the bioactive compounds of dried apple by the convection method were investigated. The results showed that PEF had a significant effect on the degradation of some bioactive compounds, such as polyphenol, flavonoid, and ascorbic acid [23]. The drying kinetics and quality of the final product were investigated for two different cultivars of apples in a convective dryer with four different temperatures in the range of 30-60 \({}^{\circ}\)C and a constant air speed of 1 m/s. The effective moisture diffusion coefficient increased via temperature, and the acidity and sugar content decreased for both cultivars after drying [24]. In another study, the qualitative characteristics (color changes, antioxidants, phenol, flavonoid) of sweet potato dried in the combined hot air-infrared dryer were investigated. The results showed that color changes and bioactive compounds are better in combined drying conditions with an intermittent strategy [25]. The quality characteristics of the final dried product depend on the temperature levels, mass transfer mechanism, and other parameters in addition to the drying method. Information on how moisture exits and mass transfer occurs in different drying methods helps a great deal in the design, quality improvement, and control of dryers as well as regarding storage and transportation methods [26; 27].