## 1 Introduction  
Many researchers are currently committed to finding sustainable alternatives to synthetic plastics, which not only harm the environment but also rely on the depletion of petroleum crude. This drive stems from the pressing need to mitigate the negative impact of petroleum-based plastics on the environment. Currently, there are biodegradable plastics like PBAT (poly(butylene adipate-co-terephthalate), a copolymer of adipic acid, 1,4-butanediol, and terephthalate acid), PBS (poly(butylene succinate), derived from direct esterification of succinic acid with 1,4-butanediol), PLA (poly(lactic acid), derived from sustainable sources), PHA (polyhydroxyalkanoates), and PHB (polyhydroxybutyrate, manufactured by microorganisms), which are eco-friendly alternatives to traditional plastics. Furthermore, over the past few years, there has been a growing focus on biodegradable polymers, which are derived from other sources, such as chitin from shrimp shells [1], gelatin extract from fish [2], starch from plants such as potato, corn, rice, and wheat [3], and pectin from ripe fruits, especially from apples, oranges, and currants [4]. Another alternative to biodegradable film production is to use flours, which are complex mixtures where starch, protein, lipids, and fibers are naturally present in the matrix [5; 6]. The utilization of wheat flours for the production of bioplastics presents a cost-effective and energy-efficient alternative to purified starch, giving materials compelling functional characteristics, albeit with a drawback of reduced resistance to breaking [7; 8]. Wheat flour, a popular processed grain product consumed worldwide, is primarily composed of starch and gluten. These macromolecular constituents play a crucial role in determining the fundamental functional and structural characteristics of wheat flour [9]. The primary constituent of wheat flour is starch, which is mainly composed of amylose (20-30%) and amylopectin (70-80%), making up around 70-75% of its overall composition [10; 11]. Additionally, wheat flour contains protein, accounting for approximately 8-14%, and minor components like lipids, which constitute about 2% of its composition [12]. Additionally, it includes non-starch polysaccharides, making up around 2-3% of its composition, along with essential minerals, vitamins, antioxidants, and other crucial nutrients [13]. Plasticizers are substances that, upon being introduced to another material, result in the softening or increased flexibility of said material. While this broad definition encompasses a wide range of products, the Council of the International Union of Pure and Applied Chemistry (IUPAC) adopted the following definition of a plasticizer: A plasticizer is a substance or material incorporated in a material (usually a plastic or elastomer) to increase its flexibility, workability, or distensibility. In addition, a plasticizer may reduce the melt viscosity, lower the temperature of a second-order transition, or lower the elastic modulus of the product [14]. Glycerol and sorbitol have proven to be efficient hydrophilic plasticizers in certain polysaccharide film formations [15; 16]. The most used plasticizers that can be incorporated are glycerol, sorbitol, diethanolamine, triethanolamine, and polyethylene glycol [17; 18]. Glucose, can also lead to better strength, flexibility, and biodegradability of wheat flour films [19]. Coffee is one of the most consumed beverages in the world. Coffee silverskin (CS), refers to the outer layer of green coffee beans that is released as a by-product during the roasting process. It accounts for approximately 4% (\(w/w\)) of the total weight of coffee beans [20]. Few reports on the applications of CS in film production are available, as it mainly consists of polysaccharides, such as in the form of cellulose (24%), hemicellulose (17%), and lignin (29%).