Korean team develops edible biofilm to extend shelf-life of fruit

Scientists in South Korea have developed an edible biofilm that can extend the shelf-life of fruit, cutting food waste and replacing synthetic packaging.

According to the team from Chungnam National University, the film, made from chitosan (CS) and gallic acid (GA) conjugate, has exceptional mechanical strength and solubility, offering a sustainable packaging solution to retain the freshness of fruits,

Chitin, a natural polymer derived from the crustacean endoskeleton, is chemically modified to produce chitosan (CS). CS is non-toxic, biodegradable, and has remarkable film-forming abilities.

However, certain limitations, including weak barrier and low antimicrobial properties, hinder its potential as a food coating material. To address this limitation, the team of researchers, led by Professor Won Ho Park, incorporated a polyphenolic compound, gallic acid (GA), to produce a CS-GA conjugate. GA is abundantly available in plants and is well known for its excellent antimicrobial and antioxidant properties.

Park said: “We wanted to develop a CS-based biofilm with enhanced food coating properties, and we were hopeful that the incorporation of GA might help in achieving that.”

In the study, which will be published in Volume 463 Issue 2 of Food Chemistry on 15 January, 2025, the team reports the synthesis and characterisation of a CS-GA conjugate film. They compared it with CS films to assess GA’s enhancement effects and tested its efficacy on stored mini bananas and cherry tomatoes.

They observed that the developed film exhibited enhanced mechanical strength, offering protection against food damage during transportation, and improved antioxidant properties, leading to extended shelf-life. It also showed improved antibacterial activity against two types of bacteria, confirming its effectiveness against multiple microbial species and superior UV-blocking capabilities to prevent photo-discoloration and damage.

Explaining the findings of the storage test. Park said: “Many consumers are concerned about remaining coating residues on the fruits. The washability of this conjugate makes it appealing for these consumers. Also, we observed a significant reduction in dehydration, discoloration, and mass loss of the stored fruits when the coating was applied. This indicates shelf-life extension and freshness retention.”

Park believes the new technology could play a significant role in reducing food waste and also contribute to the United Nations’ Sustainability Development Goals of halving the food waste by 2030.

“In the past, the primary strategy for addressing food waste reduction-related issues was to gather and dispose of food scraps. However, our research suggests that by enhancing food preservation capabilities using eco-friendly approaches, we may significantly reduce food waste occurring during the distribution process,” he said.