The Development and Analysis of Modified Chitosan-Gelatin Composite Films Using Ultrasound Treatment Followed by Enzymatic Crosslinking

This research aims to improve the physical and chemical characteristics of gelatin (GE)-chitosan (CH) composite films by adjusting their mass ratios (50:50, 75:25, 25:75). The findings revealed that a higher concentration of CH enhanced the tensile properties (TP) of the films, resulting in greater strength compared to those with a higher GE content. However, this increase in CH was associated with a reduction in elongation at rupture (ER). Importantly, films with elevated CH ratios demonstrated lower water vapor permeability (WVP) and solubility (WS). Films produced using the CH75:GE25 formulation exhibited superior mechanical strength with reduced WVP and WS, indicating their potential for further enhancements. This research also investigated the impact of high-intensity ultrasound (US) treatment in conjunction with microbial transglutaminase and tyrosinase (MTE) on the CH75:GE25 films. Applying US at 300 W with MTE treatments led to an elevation in thermal degradation temperature and enhanced thermal properties. FTIR analysis revealed that enzymatic activity and US treatment induced structural modifications and bond formation among biopolymers, especially in the regions of amides and the stretching vibrations of O-H and N-H. The synergistic effects of US and MTE treatments resulted in increased film thickness, decreased ER, and improved TP, which can be ascribed to the cross-linking of enzymes enhanced by US. Although integrating US and MTE treatments led to an increase in WVP, the overall findings indicated that this approach could significantly enhance the composition and physical characteristics of the composite films, resulting in a novel material with improved mechanical properties.