Lotus Seed Protein Hydrolysate Enhances the Mechanical, Barrier, and Thermal Properties of Propylene Glycol Alginate Bio‐Composite Films

As petroleum‐based plastics contribute significantly to environmental pollution, the development of novel biodegradable and even edible packaging materials has become a research hotspot. In this study, lotus seed protein hydrolysate (LSPH) was extracted and used to fabricate a propylene glycol alginate (PGA)/LSPH composite film. The antioxidant activity of LSPH was predicted through structural analysis and bioinformatics tools, complemented by peptide sequencing and amino acid composition analysis. The composite film with 0.2% LSPH/PGA exhibited the highest tensile strength (35 MPa) along with improved elongation at break. Moreover, this film demonstrated the lowest water vapor permeability (WVP), enhanced surface hydrophobicity, and increased thermal stability. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses indicated that the addition of LSPH led to the formation of non‐covalent bonds—including hydrogen bonds, hydrophobic interactions, and electrostatic interactions—with other components in the composite film, contributing to a homogeneous and smooth microstructure.