Influence of ultrasonic application on soybean aqueous extract based composite edible film: Characterization and their food application

In this study, a soybean aqueous extract-based composite film was developed by incorporating beeswax, clove essential oil, and span-20 via ultrasonication. The effect of ultrasonication power level (0–600 W) on the rheological properties of the film forming solution (FFS) and important film properties such as water vapor permeability, tensile strength, elongation at break, and opacity was evaluated. It was found that ultrasonication treatment until a power level of 400 W at a constant treatment condition of 15 min and a frequency of 20 kHz improved barrier (water vapor permeability: 2.91 × 10−10 g m/m2·Pa·s) and mechanical properties (tensile strength: 2.53 MPa). Ultrasonication considerably reduced the apparent viscosity of FFS from 1.32 Pa s (control) to 0.188 Pa s (600 W) and improved the flow behavior. The smooth and homogenous surface obtained in SEM analysis validated the enhanced properties obtained for ultrasonication treated films. Model fitting of moisture sorption data of the experiments indicated that the GAB model is best suited to predict the moisture uptake behavior of developed films at all selected temperatures (25, 35, and 45 °C). Sealed samples exhibited a tearing failure during testing with a seal strength value of 59.16 N/m. A qualitative biodegradation test resulted in the degradation of films within 12 days, making them an eco-friendlier packaging option. Application of the developed film as a packaging material for muffins showed that soybean aqueous extract-based film could maintain the moisture content and textural parameters of muffins for up to six days under ambient storage.