New Shellac-Based Coating Enhances Sustainable Food Packaging

Researchers from Mae Fah Luang University in Thailand and Queen Mary University in London have developed a novel shellac-based coating aimed at improving the gas barrier properties of moulded pulp packaging. This innovation targets the growing demand for recyclable and compostable food packaging solutions suitable for various food types, including instant, dehydrated, frozen, and chilled products.

Moulded pulp, made from renewable materials like eucalyptus wood and sugarcane bagasse, currently constitutes over 30% of all paper-based packaging materials. While it is recognized for its sustainability, its inherent limitations in gas barrier properties and resistance to water and oil have hindered its effectiveness in extending product shelf life.

Traditionally, these limitations are addressed by laminating pulp with petroleum-based polymers, such as polyethylene, and metals like aluminium, which complicates recycling and composting efforts. The new research seeks to overcome these challenges by utilizing a biodegradable coating derived from shellac, a natural resin produced by lac bugs.

Shellac is known for its non-toxic nature and has applications in various industries, including food and medicine. However, its brittleness and high oxygen permeability have limited its use as a standalone coating. To enhance its performance, the researchers created a nanocomposite layer combining shellac with modified nanofibrillated cellulose (mNFC), which improves water resistance and compatibility.

The study, published in Polymer International, systematically evaluated the effects of the nanocomposite coating on the morphology, barrier properties, and mechanical strength of the moulded pulp. Results indicated that the coated samples exhibited water vapour and oxygen transmission rates comparable to conventional packaging materials like low-density polyethylene and polyethylene terephthalate.

Additionally, the nanocomposite coating provided superior water resistance and greaseproof characteristics, enhancing the tensile properties of the moulded pulp. The thermal stability of the samples reached approximately 250 °C, confirming their potential for practical food packaging applications.

This development aligns with ongoing industry efforts to promote sustainable packaging solutions, as highlighted by the recent calls from the Alliance for Beverage Cartons and the Environment for further regulatory changes in packaging waste management.