Macromolecular structure–property relationships in gelatin based edible films for food packaging applications

Yustira A., Zikri A., Maulida A. J., Dhanratz A., Ambarita A. C.

Bioresource Technology Reports, vol.34, 2026 (ESCI, Scopus)

Abstract

Gelatin-based edible films constitute physically cross-linked protein networks whose mechanical and transport properties are governed by molecular architecture and intermolecular interactions. However, the structure–property relationships controlling film performance remain poorly unified across different gelatin sources and extraction pathways. This review provides a comprehensive and mechanistically oriented synthesis of recent advances in gelatin-based edible films and coatings, focusing on how source selection and extraction strategies modulate macromolecular network architecture and, consequently, the material behavior. Gelatin derived from mammalian, fish, poultry, and insect biomass is critically examined in terms of amino acid composition, molecular-weight distribution, and Bloom value, and their roles in governing hydrogen bonding density, chain packing, and effective cross-linking. Major extraction routes, conventional acid/alkali–thermal treatment, enzyme-assisted extraction, microwave-assisted extraction, and ultrasound-assisted extraction. Are systematically compared with respect to their effects on chain conformation, secondary structure organization, and network formation. These molecular features are explicitly linked to key film properties, including tensile strength, elongation, swelling behavior, water absorption, FTIR characteristics, pH responsiveness, and water vapor permeability. By integrating molecular-level interpretation with macroscopic performance, this review establishes a unified structure–property framework that explains the wide variability reported in gelatin-based films and enables rational material design. The analysis further highlights the potential of non-conventional gelatin sources and optimized extraction technologies for biomass valorization and sustainable packaging development. Overall, this work provides a macromolecular perspective for the design of high-performance, sustainable gelatin-based edible films and coatings for advanced food packaging applications.