Reinventing sustainable food packaging of the future

Biodegradable food packaging materials offer a sustainable alternative to conventional plastics for food protection, but their applications are often limited by lower oxygen barrier performance and mechanical strength. Now, Professor Andi Dirpan from Hasanuddin University, along with researchers from India and Malaysia, have developed multilayered polylactic acid films reinforced with microcrystalline cellulose and oxygen scavenger butylated hydroxytoluene. The resulting solution combines oxygen-scavenging functionality with enhanced mechanical performance, offering a promising alternative bioplastic for food packaging applications.

Plant-based biodegradable plastics, such as polylactic acid (PLA), are a promising alternative, but can fall short of conventional plastics as they typically do not block oxygen as well, nor do they hold up mechanically. Researchers have tried introducing additives to improve their strength or make them actively scavenge oxygen. However, these two enhancements are rarely combined and tested together. The real challenge lies in building a biodegradable plastic that actively manages oxygen while maintaining the strength and functionality required for food packaging.

With this goal in mind, Professor Andi Dirpan and his team at Hasanuddin University, Indonesia, have developed multilayer PLA-based films reinforced with microcrystalline cellulose (MCC) and enhanced with an oxygen-scavenging compound, butylated hydroxytoluene (BHT). This innovative biodegradable material combines oxygen-scavenging functionality with enhanced mechanical performance, offering a promising alternative to conventional plastics.

One notable aspect of their work was the selection of cellulose source. Rather than using cellulose from wood or crops, the researchers produced bacterial cellulose from fermented coconut water, mimicking the process used to make ‘nata de coco’, a jelly-like food produced by fermented coconut water. The reason for this selection was because bacterial cellulose is highly pure and rich in fibre, making it an effective reinforcing component. During fermentation, the bacteria produced a dense cellulose membrane, which the researchers purified and processed into MCC powder for use as an additive. It was then blended into a PLA film built in three thin layers, with the oxygen scavenger BHT placed only in the two inner layers that would face the food.

The team tested films made with different amounts of MCC powder and compared their coconut water-derived cellulose (MCC nata de coco) to a common commercial alternative (MCC avicel pH 102). Adding more cellulose made the films mechanically stronger and lowered the amount of oxygen that could pass through. However, it also made the films denser and noticeably stiffer. At a microscopic level, MCC nata de coco produced a more uniform, defect-free structure than the commercial alternative, which the researchers attributed to its higher purity and fibre content. Oxygen permeability tests also showed the resulting film performed better than plain PLA.

Notably, the film broke down quickly and steadily when buried in soil. “The biodegradation rate was found to be 28.86% over 25 days,” Dirpan said. “These results show that the level of biodegradation is in accordance with that of biodegradable plastics made from similar polymers, which is over 25% within a period of 25 days.”

Through careful analysis of the relationship between structure, properties and functions, the study highlighted an important trade-off. Although the reinforced film showed improved stiffness and useful oxygen-scavenging properties, it was brittle and did not stretch well before breaking. This matters because packaging materials must protect food while withstanding manufacturing, transport and day-to-day handling. Simply put, the results show that combining reinforcing and oxygen-scavenging additives in a multilayer biodegradable system is promising, but the balance between barrier performance and flexibility still needs improvement.

Overall, this research provides useful design criteria for creating ecological plastics for food packaging in the future.

The study is available online and will be published in Volume 6 of ASEAN Journal for Science and Engineering in Materials on 1 March 2027.

Image credit: iStock.com/Theerawit Jirattawevut