The effects of glycerol addition on the physicochemical, structural and mechanical properties of salt-gelatinized rice starch-based film

Starch-based films have garnered significant interests due to their biodegradability properties. Salt gelatinization is a promising technique for producing starch-based films, characterized by its simplicity, low temperature, and minimal energy usage. This work assessed the impact of glycerol incorporation on the physicochemical, structural, and mechanical characteristics of three varieties of rice starch-based films, namely CaCl 2 -gelatinized without glycerol (CG), CaCl 2 -gelatinized with glycerol (CGG) and heat-gelatinized with glycerol (HGG) films. Films gelatinized with CaCl 2 exhibited reduced thickness (0.34 mm) and increased transmittance (75.13%) compared with heat-gelatinized films. The incorporation of glycerol resulted in CaCl 2 -treated films with maximum elongation at break (249.7%) approximately five times that of heat-gelatinized films characterized by a smooth, compact, and homogeneous structure. The results indicate that 1 mol/L of CaCl 2 can facilitate the preparation of starch-based films and CaCl 2 functions efficiently as a pasting agent in the production of starch-based films at room temperature (25 °C), while glycerol serves as a plasticizer, significantly improving mechanical properties and appearance. • CaCl 2 can gelatinize indica-rich starch at 25 °C as a pasting agent. • Starch-based film prepared by salt-gelatinization is energy-efficient and environmentally friendly. • The mechanical properties and appearance of CaCl 2 -gelatinized films are better than heat-gelatinized film. • Glycerol considerably improved CaCl 2 -gelatinized films' elongation at break, structure, and fracture surface.