Development and Optimization of Edible Antimicrobial Films Based on Dry Heat-Modified Starches from Kazakhstan

This study aimed to design and optimize an edible antimicrobial film incorporating thermally modified starches using a systematic experimental approach. A comprehensive analysis of six starch types-both native and dry heat-modified-was conducted to evaluate their gelatinization clarity, freeze-thaw stability, microstructure (CLSM), and in vitro digestibility. Corn and cassava starches were selected as optimal components based on their physicochemical performance. A series of single-factor experiments and a Box-Behnken design were employed to assess the influence of starch concentration, gelatinization time, glycerol, and chitosan content on film properties including tensile strength, elongation at break, water vapor permeability (WVP), and transparency. The optimized formulation (5.0% starch, 28.2 min gelatinization, 2.6% glycerol, 1.4% chitosan) yielded a transparent (77.64%), mechanically stable (10.92 MPa tensile strength; 50.0% elongation), and moisture-resistant film. Structural and thermal analyses (SEM, AFM, DSC, TGA) confirmed the film's homogeneity and stability. Furthermore, the film exhibited moderate antioxidant activity and antibacterial efficacy against Escherichia coli and Staphylococcus aureus. These findings demonstrate the feasibility of using dry heat-modified Kazakhstani starches to develop sustainable antimicrobial packaging materials. However, further studies are needed to explore sensory attributes, long-term storage performance, and compatibility with different food matrices.