The developed natural polysaccharide-based edible coating can replace synthetic packaging and provides a sustainable solution to reduce global food waste
Non-recyclable food packaging materials available on the market contribute to environmental pollution and highlight the urgent need for environmentally friendly and biodegradable alternatives. Now researchers from Korea have developed a conjugate of chitosan (CS) and gallic acid (GA) as an environmentally friendly packaging option. The CS-GA films have exceptional mechanical strength and solubility, providing a sustainable packaging solution to preserve the freshness of fruits. In the future, this green technology has the potential to sustainably reduce global food waste.
With significant improvements in transportation technology, the accessibility of fresh food has improved significantly. However, this progress comes with increasing concerns about food waste during transportation and storage. Globally, around 17% of food is wasted at retail and consumer levels, leading to problems such as groundwater contamination, dangerous gas emissions and the spread of infectious pathogens, all of which contribute to environmental pollution. To develop efficient, cost-effective and environmentally friendly food preservation technologies, researchers around the world are exploring alternatives for developing packaging materials. Among these, edible coatings made from naturally occurring polymers have shown particular promise.
These protective coatings can protect fruits from postharvest decay by preventing water loss and gas exchange, reducing the need for refrigeration or synthetic preservation while extending shelf life.
Chitin, a natural polymer derived from the endoskeleton of crustaceans, 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, a team of scientists led by Professor Won Ho Park from Chungnam National University, South Korea, incorporated a polyphenolic compound, gallic acid (GA), to produce a CS-GA conjugate. GA is abundant in plants and is known for its excellent antimicrobial and antioxidant properties.
Prof. Park goes into more detail about her study and says: “We wanted to develop a CS-based biofilm with improved food coating properties and hoped that incorporating GA could help with this.” This paper was made available online on September 16, 2024 and is published in Volume 463, Issue 2 of Food chemistry on January 15, 2025. In this study, the team reports the synthesis and characterization of a CS-GA conjugate film. They compared it with CS films to assess the reinforcing effects of GA and tested its effectiveness on stored mini bananas and cherry tomatoes.
They found that the developed film had improved mechanical strength, providing protection against food damage during transportation, and improved antioxidant properties, resulting in a longer shelf life. It also demonstrated enhanced antibacterial activity against two types of bacteria, confirming its effectiveness against multiple species of microbes and superior UV blocking properties to prevent photo-discoloration and damage. Explanation of the memory test results. Prof Park says:“Many consumers are concerned about remaining coating residue on the fruit. The washability of this conjugate makes it attractive to these consumers. Additionally, after applying the coating, we observed a significant reduction in drying, discoloration, and mass loss of the stored fruit. This indicates an extension of shelf life and preservation of freshness.”
In the future, this eco-friendly technology could play an important role in reducing food waste and also contribute to the United Nations' sustainability goals of halving food waste by 2030. Prof. Park shares his final thoughts: “In the past, the main strategy for solving problems related to food waste reduction was to collect and dispose of food waste. However, our research suggests that by improving food preservation options using environmentally friendly approaches, we can significantly reduce food waste created during the distribution process.”
reference
Original paper title: Chitosan-gallic acid conjugate edible coating film for perishable fruits
Magazine: Food chemistry
DOI: 10.1016/j.foodchem.2024.141322