Pineapple leaf bioplastic with antimicrobial coating shows biodegradable food packaging potential

21 Oct 2021 --- Researchers at the King Mongkut’s Institute of Technology Ladkrabang in Thailand have developed a polylactic acid (PLA) composite pineapple leaf fiber biopolymer. The composite could help meet the growing demand for biodegradable food packaging. 

The formulation consists of 10% PLA and pineapple leaf fiber, which exhibited enhanced melting temperatures, heat resistance and barrier properties. The antimicrobial material also inhibited the growth of various foodborne pathogens and minimized the number of foodborne pathogens on material surfaces.

“We envision the material could enhance food safety, food quality and prolong shelf life, especially for ready-to-eat foods,” Dr. Tatsaporn Todhanakasem, associate professor at the faculty of food industry at King Mongkut’s Institute of Technology Ladkrabang, tells PackagingInsights.

Plentiful pineapple leaf waste
Todhanakasem has high hopes the material could be commercialized in the near future, considering continued access to pineapple leaf waste in Thailand. 

“Thailand has 75 pineapple processing factories, and these alone generate approximately 200 metric tons of agricultural waste per day,” she highlights.

“Recently, agricultural fibers have become more value-added products for food packaging to replace non-biodegradable plastics,” she continues, flagging non-biodegradables as “one of the most serious sources of toxic pollution on the planet.”

Pineapple leaf fiber after bleaching.The antimicrobial addition
The PLA material was coated with crude supernatants containing nisin, a polycyclic antibacterial peptide often used as a food preservative. 

The antimicrobial coating was shown to inhibit the growth of pathogens, including Salmonella, in culture conditions. It also reduced the number of tested pathogens on the coated material surfaces.

According to Innova Market Insights, 59% of global consumers believe packaging’s protective function is more important since the COVID-19 virus outbreak.

Throughout the pandemic, consumer hygiene concerns have heightened, giving rise to antimicrobial technologies, such as Arjowiggins’ surface treatment for paper products and Taghleef Industries’ Derprosa Antibacterial film.

The resulting PLA material after compression molding.Upcycling strides
Research on converting food and agricultural waste into hygienic packaging materials is advancing worldwide. 

Earlier this year, the EU-funded Dafia project released results of an investigation into turning fish and municipal waste into biopolymers and other barrier packaging materials.

Meanwhile, upcycled cocoa fruit shells and oat husks are being used to create Spoontainable’s edible spoons for ice cream and frozen desserts.

PackagingInsights also recently spoke with Indian chocolate bar brand Kocoatrait about its snack wrappers made from reclaimed cotton from garment factories and cocoa shells.

By Anni Schleicher