**4.1 Polysaccharides**

Biopolymers used as raw materials in the manufacture of biodegradable films should be renewable, abundant, and cost-effective. In some cases, they can be derived from waste. Polysaccharides such as starch, cellulose, and chitosan are among the materials being researched under consideration for biodegradable packaging films and biocomposites. These polysaccharides can procedure films with good barrier properties against gas exchange including oxygen and carbon dioxide. On the other hand, tensile strength and elongation percentage are the important mechanical properties because their desirable values are needed to maintain the integrity of the packed food. The tensile strength values that have been showed by polysaccharide-based films differ, but actually some of them exhibit similar values to those noticed in synthetic polymers. Tensile strengths of films based on high amylose starch or chitosan, for example, are comparable to high-density polyethylene films. The major area of concern is the elongation percentage values, which are significantly lower than those observed in synthetic polymers. Accordingly, researchers are looking into combining polysaccharides with other materials to improve the barrier and mechanical properties of biopolymers that could replace synthetic polymers [51].

## *4.1.1 Starch*

Starch is a polysaccharide that naturally accumulates in plants. Potatoes, corn, and wheat are the primary sources of starch for commercial production. Starch contains two major polymeric constituents: amylose in straight chains and amylopectin with highly branched glucose chains [52]. Starch on its own is brittle and incapable of forming films with the desirable properties. For product packaging, starchbased materials have poor mechanical properties. Unless it is plasticized with other materials, chemically modified, or modified with a combination of such forms of treatment, it lacks high elongation, tensile, and flexural strength. Rewardingly, glycerol is the key player used as a plasticizer [53].
