## 1 Introduction  
Cassava (_Manihot esculent_ Crantz) is one of the most important staple crops in tropical and subtropical regions. Thailand is the third largest cassava producer, with a production of 30.6 million tonnes over 1.5 million ha [1]. Cassava is a vital source of carbohydrates from its roots, while its leaves are often abandoned in the field. Cassava leaves are rich in nutrients (proteins, vitamins) and bioactive compounds (carotenoids, chlorophylls), making them valuable supplementary sources of nutrition for humans [2, 3]. However, their high cyanide content 1315.97 \(\pm\) 141.64 mg/kg (dry basis, d.b.) limits direct consumption. In some African and Asian countries, cassava leaves are consumed as vegetables after appropriate processing [4, 5]. Fresh cassava leaves contain 63.41-73.14% (wet basis, w.b.) moisture [3], which gives them a short shelf life. Drying is commonly used to stabilize perishable produce by reducing the water content to a safe level, thereby preventing microbial spoilage.  
The drying characteristics and modeling of the drying process are crucial for determining the optimal drying conditions and predicting the drying time needed to achieve the target moisture content of dried products. The drying behavior of agricultural productscould be described using various models; however, thin-layer models are widely used to describe the drying behavior of different types of leaves [6]. Several mathematical models are suitable for drying leaves, such as the [PERSON] model for black tea [7], the [PERSON] model for bay leaves and thymus leaves [8; 9], the [PERSON] and Pabis model for mint leaves [10], and the [PERSON] model for parsley leaves [11]. For cassava, the thin-layer drying model has been studied for cassava root pulp [12]. However, the drying of cassava leaves has not been examined, indicating a need for further investigation to determine a suitable mechanism and drying behavior for cassava leaves.  
The heat during the drying process can affect the quality of dried leaves. Bioactive compounds content, including luteoxanthin, lutein, zeaxanthin, \(\beta\)-carotene,tocopherol, vitamin C, chlorophyll-\(a\), chlorophyll-\(b\), and antioxidant activity, decreased in _Moring oleifera_ leaves after hot-air drying [13]. Different drying temperatures can significantly impact the final quality of dried leaves. In dried sea buckthorn leaves, carotenoids, chlorophylls, and total phenolics decrease as drying temperatures increase [14]. Similarly, vitamin C in dried stevia leaves decreased with increasing drying temperature, while total phenolics and total flavonoids increased after drying at 30 \({}^{\circ}\)C, 40 \({}^{\circ}\)C, and 50 \({}^{\circ}\)C but decreased at high temperatures (60 \({}^{\circ}\)C, 70 \({}^{\circ}\)C, and 80 \({}^{\circ}\)C) [15]. The cyanide content in cassava leaves is retained at 64.9% after oven drying [16]. The optimum temperature for linamarase activity is 55 \({}^{\circ}\)C [17].  
This study explored efficient drying temperatures for maximizing the quality of dried cassava leaves. The drying process and product quality were optimized by analyzing drying behavior using an appropriate kinetic model at various temperatures. The effects of hot-air drying at temperatures ranging from 40 to 80 \({}^{\circ}\)C on leaf quality were assessed. The findings will help identify the optimal drying conditions for maintaining nutrients and bioactive compounds and eliminating cyanide in cassava leaves.