Development of Buckwheat Starch‐Capric Acid Complex‐Based Film: Process Optimization and Film Characterization

ABSTRACT To overcome the limitations of starch usage alone, the film formation ability of the buckwheat starch‐capric acid complex (BS‐CA) was optimized, and the films were characterized. Significant models were obtained for tensile strength (TS) and Young's modulus (YM) of BS‐CA film ( p < 0.0001). The glycerol/starch ratio, temperature, and their interactions were significant in the YM model ( R 2 is 0.9851). The BS‐CA film had a better water vapor barrier (0.463 ± 0.02 g mm/m 2 h kPa), with lower water solubility (WS) (34.18 ± 1.70%) and moisture content (MC) (16.87 ± 0.09%) than the buckwheat starch (BS) film ( p < 0.05). It had lower thickness (0.073 ± 0.00 mm) and TS (0.624 ± 0.04 MPa) but higher elasticity (114.60 ± 3.12%). The non‐covalent interactions were determined between BS and CA, since new peaks were not observed in the film's FTIR spectrum. BS‐CA film had a typical V‐type crystalline structure and had slightly lower decomposition temperatures than the BS film. Contact angle measurements (55.19° ± 1.7), and images of AFM topography and SEM showed that the BS‐CA film surface was hydrophilic; height and average roughness values were 1014 and 276 nm, respectively, which were quite higher than those of BS film. The results reveal that starch modification with fatty acid is a promising way to develop starch‐based films to be used in practical applications.