Synergistic enhancement of foaming and thermal properties of gelatin based composite gel foam by blending biopolymers

This study establishes a synergistic multi-component strategy to engineer fully bio-based, high-performance gelatin composite foams. By strategically integrating l-carrageenan(l-car), pectin, chitosan, sucrose, and microbial transglutaminase (mTG), we achieve tailored control over material properties. The incorporation of sucrose significantly enhanced thermal stability, elevating the melting point from 39.3 °C (pure gelatin) to 41.25 °C. Mechanically, all additives except mTG improved the compressive modulus and strength, with chitosan yielding the highest performance due to polyelectrolyte complex formation. Importantly, a quantitative power-law model reveals that foam expansion is governed by the competition between viscosity and gelation kinetics. These findings provide a versatile design paradigm for fabricating sustainable, tailorable bio-foams, offering a promising alternative to conventional polymer foams in packaging and insulation applications. • A novel five-biopolymer gelatin composite gel foam was successfully fabricated. • The melting point of the composite gel was enhanced to 41.25°C, exceeding pure gelatin. • Chitosan complexation doubled the compressive strength versus pure gelatin foam. • Enzymatic cross-linking by mTG increased the expansion ratio and melt strength. • Enhanced properties stem from physical interactions and refined bubble microstructure.