Shellac, a natural and biodegradable resin, is showing remarkable potential to transform the sustainability profile of food packaging. A recent study focused on coating bagasse paperboard (BP)—a material derived from sugarcane waste—with varying concentrations and layers of shellac. The results revealed significant improvements in barrier performance, opening the door for high-functionality, compostable packaging solutions that could rival conventional plastic-based options.

The study tested shellac concentrations of 24%, 40%, and 60%, along with 1–4 coating layers, to determine the optimal balance between performance and material use. The standout performer was a two-layer coating at 40% concentration, which delivered dramatic enhancements:

• Oxygen permeability decreased by 99.5%
• Water vapour permeability dropped by 82.2%
• Water absorbency fell by 97.5%

These improvements are especially relevant for packaging dry food products such as chips and snacks, where exposure to oxygen and moisture significantly impacts shelf life and quality.

Thermal and mechanical resilience also saw positive results. The coating enhanced the thermal stability of the paperboard, ensuring resistance to moderate heat without compromising the material’s mechanical integrity. This is crucial for real-world applications where packaging must endure both production and transportation stresses.

One of the most impressive findings was shelf life extension. In a simulated packaging environment, potato chips stored in shellac-coated bagasse paperboard remained fresh for up to 50 days longer than those in uncoated packaging. This breakthrough demonstrates how natural materials can not only match but in some cases exceed the performance of synthetic polymers when applied with scientific precision.

Why shellac?

Shellac is a natural polyacid resin secreted by the lac bug. It is widely recognized for its film-forming properties, biodegradability, and safety in food contact applications. Historically used in pharmaceuticals and confectionery coatings, its transition to sustainable packaging aligns with growing regulatory and consumer demands for materials that are both effective and environmentally responsible.

Functional coatings: the next frontier

This study underscores a broader trend in packaging R&D: the shift toward functional coatings as a means to increase the utility of fiber-based materials. Instead of relying solely on multilayer plastics or aluminum laminates, which are hard to recycle, companies and researchers are exploring bio-based coatings like shellac to achieve necessary barrier properties while maintaining recyclability or compostability.

As discussed in resources like the EC Tech Report on Functional Coatings, the role of coatings is becoming central in achieving performance parity with plastics. In this context, shellac’s ability to balance biodegradability with functionality places it among the most promising solutions for next-generation packaging design.

Looking forward, shellac-coated paperboard may become a key enabler in the development of fully compostable or recyclable food packaging. By replacing complex, multi-material laminates with high-performance bio-coatings, the packaging industry could significantly reduce its environmental footprint without sacrificing quality or safety.

As food producers and packaging companies search for solutions to meet both regulatory and market demands, shellac presents a viable, scalable, and sustainable alternative that blends tradition with cutting-edge material science.