## 1 Introduction  
In global agricultural production, the use of plastic much has become an essential means of increasing crop yield and quality. However, its widespread application has also led to severe environmental issues. According to the Food and Agriculture Organization (FAO) of the United Nations, approximately 12.5 million tons of plastic products are consumed annually in the agricultural supply chain, with the crop production and livestock sectors alone accounting for 10.2 million tons [1]. While these plastic products enhance agricultural productivity, they also contribute to soil and water pollution, adversely affecting ecosystem health [2; 3]. In Kazakhstan, agriculture is a key pillar of the national economy, and plastic much is widely used to enhance crop yield and quality. However, due to the lack of effective recycling and disposal mechanisms, residual plastic much accumulates in the soil, leading to soil degradation and environmental pollution [4]. According to the research findings of [PERSON] et al. (2023), the accumulation of residual much increases at a rate of 15.0 kg/ha per year. When the residual mulch density reaches 1210 kg/ha, the yield reduction caused by plastic residue exceeds the yield benefits provided by mulching; furthermore, the amount of residual plastic mulch is positively correlated with soil salinity variability [5]. This issue not only raises agricultural production costs but also poses a significant threat to sustainable agricultural development. Due to its abundant availability, excellent renewability, cost-effectiveness, and biodegradability, natural starch has emerged as a promising alternative to traditional petroleum-based plastics in various fields, including agricultural mulch films, food packaging, and biomedicine [6; 7; 8]. With the global push for environmental protection and sustainable development strategies, the development of economical, efficient, and eco-friendly starch-based materials has become a key research focus. However, natural starch still faces several challenges in industrial applications, such as poor solubility, insufficient shear resistance, low mechanical strength, and a tendency to retrograde, which significantly limit its widespread adoption in biodegradable mulch films [9; 10]. To overcome these limitations, various modification techniques have been extensively studied, including physical, chemical, and enzymatic modifications [11]. Among these, physical modification techniques have gained significant attention in recent years due to their simplicity, efficiency, and absence of chemical residues [12]. Dry heat treatment (DHT), in particular, has become a popular starch modification method due to its high efficiency, environmental friendliness, and safety. This technique regulates the molecular structure and granule characteristics of starch through hot air treatment without the use of any chemical reagents [13]. Compared to other modification methods, DHT offers several advantages, such as a simple processing flow, high automation potential, and eco-friendliness, making it particularly suitable for industrial-scale production [14]. Starch granules exhibit a complex structure composed of both crystalline and amorphous regions [9]. The dense crystalline region significantly hinders the penetration of water and modification of agents into the granules, thereby reducing the reactivity and modification efficiency of natural starch [15]. During DHT, the partial breakage and rearrangement of starch molecular chains occur, leading to significant changes in the chain length distribution of amylose and amylopectin, with an increased proportion of shorter chains [16]. Simultaneously, the enhancement of hydrogen bonding and van der Waals forces forms a new molecular cross-linking network, improving the thermal stability and anti-retrogradation properties of starch [17].