The glass transition temperature (Tg) is one of the physical properties of the polysaccharides, which describes the temperature that transforms from an amorphous state to a viscous state [4]. At Tg, polymer material transits from a glassy, brittle state to a soft and flexible state. Since starch consists of both amorphous and crystalline regions, Tg of starch cannot be detected easily [4]. Native starch is not suitable for engineering applications due to its brittleness. Therefore, it requires a suitable plasticizer [15; 16; 17]. Although native starch is considered a non-plasticized material due to the presence of intra-and intermolecular -H bonding between the hydroxyl groups of starch molecules, starch can be converted into a continuous polymeric entangled phase when mixed with an aqueous or non-aqueous plasticizer such as glycerol, ethanolamine, urea, formamide, glycol, xylitol, sorbitol, sugars, and acetamide. When starch is plasticized, a semi-crystalline granule of starch is transformed into a homogeneous material due to the cleavage of hydrogen bonds between starch molecules. This behavior leads to a loss of crystallinity and lowers the glass transition temperature of starch while improving the chain flexibility. Finally, the plasticized starch becomes a petroleum-like thermoplastic starch (TPS) that is easy to process and moldable [16; 18; 19]. Glycerol is considered the most widely utilized plasticizer among various available plasticizers due to its non-toxicity, low cost, and high boiling point. Interestingly, the properties of TPS depend on the amount and the type of plasticizer added [16; 19]. According to the literature, both modified starch and native starch can be used to prepare TPS. For example, [PERSON] et al. [16] prepared TPS via dialdehyde starch, demonstrating reduced Tg, water absorptivity, hydrophilicity, and water vapor permeability with enhanced mechanical properties [16]. The semi-crystalline nature of starch is determined by the amylopectin component [20]. Water absorption and subsequent swelling of starch granule result in amylopectin-amylase phase separation and crystallinity loss [4]. Starch can also be solubilized using excess water at high temperatures (above 80 \({}^{\circ}\)C) by the depolymerization process [21]. Furthermore, starch solubilization can be enhanced using microwave, autoclave, and a boiling water bath [22; 23; 24; 25]. Starch possesses an excellent film-forming characteristic. However, the higher water absorption and low mechanical strength [1] limit starch-based materials for engineering applications. Native starch contains many hydrophilic -OH groups resulting in moisture sensitivity. Due to amorphous regions, starch exhibits low mechanical properties, such as tensile strength, elongation at break, and brittleness [1]. In order to improve the mechanical properties of TPS, numerous modification techniques have been employed [26]. Figure 3 shows the raw materials, types of modified starch, their functions, and applications available in the market. Figure 2: Schematic representation of the **(a)** Slarch granules; **(b)** Cross section of the starch granule; **(c)** Representation of the cross section of the starch granules; **(d)** Double helix structure of amylopectin; **(e)** Structure of amylose; **(f)** Single helix structure of amylose; **(g)** Structure of amylose; **(h)** Type view of the double helix clusters: **(i)** A type, (j)** B type, and **(k)** Types of amylopectin chains. The modified starch is mainly applied in the food, paper and pulp, textiles, and pharmaceutical industries [27]. In addition, a small percentage of modified starch is also used in the bioplastic industry.