Self-structuring bio-based composite coatings for food packaging

Overview

This technology offers a sustainable coating solution for food packaging based on oil-in-water emulsions that self-structure during curing into a supramolecular barrier network. The coatings are formulated from renewable bio-based film-forming thermoplastic biopolymers in the aqueous phase and crystallising compounds in the lipid phase. Upon curing, the biopolymers form a continuous network that provides oxygen barrier, mechanical strength, and structural scaffolding, while high-temperature melting lipid droplets deliver moisture barrier. The approach uses crystallising compounds that are currently by-products of the food industry, supporting circular economy principles.

The technology has been validated across three distinct application areas: post-harvest coatings to extend shelf life of fruit and vegetables, paper and molded fiber coating, and spraying onto edible films. This flexibility allows the coatings to be adapted to a range of substrates and environmental conditions including varying storage temperatures, times, pH levels, and water content.

Technical specifications

Key features:

• Oil-in-water emulsion format enables flowable, stable coatings suitable for spray, dip, or other coating application methods
• Self-structuring mechanism during curing eliminates the need for complex lamination processes
• Continuous biopolymer network delivers oxygen barrier and mechanical integrity
• Embedded crystallising lipid droplets provide moisture barrier through high-temperature melting behaviour
• Resistance to cracking and pinholing, common failure modes in conventional coatings
• Adaptable formulation using single or combined film-forming thermoplastic biopolymers from plant and microbial sources

Research and development parameters:

• Identification of suitable biopolymers and optimal concentrations for target substrates
• Definition of lipid phase volume fraction and crystallising compound content to control droplet size and phase separation
• Characterisation of self-structured network including layer formation, oxygen and water vapour transmission rates, and barrier integrity
• Validation across a range of pH conditions and oil contents using representative food products

Technology readiness level

The technology has progressed beyond preliminary proof-of-concept, with unpublished work demonstrating successful formulation of stable, flowable oil-in-water emulsions for coating applications. Validation has been completed across three application areas, confirming the technology's flexibility and adaptability under varying environmental conditions. The coatings have demonstrated significant reductions in vapour transmission rate and potential reductions in oxygen transmission rate. Further development is planned to optimise formulations for sponsor-specified substrates and to validate barrier performance against specific food product challenges.