South Korean researchers develop edible biofilm for extended fruit shelf life

A newly developed biodegradable chitosan (CS) and gallic acid (GA) conjugate fruit packaging could reduce food waste while improving sustainability and freshness, according to the latest university research. The CS-GA films developed by scientists at South Korea’s Chungnam National University are biodegradable, edible and offer elevated mechanical strength.

“This investigation explored the utilization of chitosan, an abundant natural resource, for food packaging applications. The research methodology employed a limited array of chemical agents, with the coating process exclusively involving substances and water,” study lead professor Won Ho Park from Chungnam National University, tells Packaging Insights.

“The resultant sustainable system, derived from eco-friendly materials, exhibits potential for diverse food packaging applications and may offer a viable solution to mitigate environmental concerns associated with conventional packaging materials.”

The packaging alternative can protect fruit from post-harvest degradation by preventing water loss and gas exchange. It reduces the need for refrigeration or synthetic preservation, extending shelf life. Park says the solution could address the increasingly relevant food waste challenge.

“Approximately 30% of global agricultural land produces food that is eventually lost or wasted, necessitating strategies to reduce this waste.”

Environmental implications

The study “Chitosan-gallic acid conjugate edible coating film for perishable fruits,” soon to be published in the journal Food Chemistry, describes the synthesis and characterization of a CS-GA conjugate film and compares it to CS films on their efficacy in preserving stored mini bananas and cherry tomatoes.

“This study investigated CS derivatives as edible coatings to prolong food shelf life. While soluble CS derivatives like glycol CS are effective coatings, their antimicrobial efficacy decreases with greater solubility,” explains Park.

CS-GA conjugate coating for sustainable fruit preservation (Infographic credit: Chungnam National University).

“To counter this, GA [a polyphenol] was conjugated with CS using ‘EDC/NHS chemistry’ (carbodiimide and N-hydroxysuccinimide) to develop edible coating solutions. The resulting CS-GA films demonstrated excellent solubility, mechanical strength, UV-blocking capabilities, and enhanced antioxidant and antimicrobial properties.”

“Non-degradable petroleum-based polymers such as PE and PP are used as general packaging film. As a result, the problem of environmental pollution has emerged, and the demand for biodegradable packaging materials is increasing.”

Park argues that while polymer materials are essential to contemporary society and find applications across diverse fields, “their limited biodegradability significantly impacts ecosystems, contributing to global warming and microplastic pollution.”

“Materials derived from natural sources or methodologies that substantially enhance performance through partial modifications are considered potential approaches to address and mitigate environmental pollution issues while fostering sustainable industrial development.”

“This perspective is believed to provide a foundation for preserving a healthy planet for future generations.”

Future applications

Park discusses if and how CS-GA technology could be adapted for use with other foods or items besides fruits.

“The coating method of fruits proposed in the research was implemented through dip-coating and drying processes. However, if the coating material is formulated as a film or applied via spray methodology, it is considered to be sufficiently applicable to other foods or items.”

Discussing how this biofilm compares to conventional packaging in terms of cost and scalability, Park explains that “chitosan is a cost-effective natural polymer that exists abundantly on Earth, and is thought to be easier to scale-up than other materials.”

“In addition, it was confirmed that the polymer modification system is already on the market as a hemostatic agent or wound coating material using the same reforming process on the line we know. Therefore, if the scale-up process conditions are optimized, mass production and prototypes are expected to be possible.”