Researchers develop hydrogel coating to extend shelf life of fresh produce

In a significant breakthrough, researchers at St. Cyril’s College, Adoor, have developed a hydrogel-based coating that can extend the shelf life of fruits and vegetables for up to 30 days.

The innovative solution, created by the college’s Carbon Research Group, addresses key limitations of traditional preservation methods. Unlike chemical preservatives often used in industrial settings, which can alter taste, texture, and nutritional value, the hydrogel provides a safer and more natural alternative.

“Refrigeration can extend the freshness of vegetables by just 7 to 14 days. This method, however, is energy-intensive, often inaccessible to small-scale farmers, and may lead to uneven preservation or premature spoilage,” explained Anoop Chandran, faculty member in the department of Physics and lead mentor of the project. “Our hydrogel forms a hydrated barrier around the produce, preventing excessive moisture loss and helping maintain firmness and texture.”

Unlike wax coatings, it can be easily washed off with water, leaving no harmful residue behind.

The research team includes Fr. Rejo Mathew Joseph, a research scholar, and Runcy Wilson from the Department of Chemistry. The hydrogel’s characterisation and testing were conducted with assistance from Sony George at the Department of Food Technology, TKM Institute of Technology, Kollam.

According to Father Joseph, the coating works by slowing the natural respiration rate of fruits through controlled gas exchange, primarily oxygen and carbon dioxide. “This reduction delays ripening and aging, while simultaneously inhibiting microbial growth by reducing exposure to pathogens and creating a less hospitable environment for contamination,” he said.

“It also provides a protective buffer against minor physical damage that can otherwise accelerate spoilage.”

Safety concerns

The researchers highlight the risks associated with currently used preservation agents such as calcium carbide, a chemical banned in many regions due to safety concerns. Even food-grade wax coatings raise issues as they often contain morpholine, a compound linked to potential health risks when consumed in large quantities. These coatings can also alter the flavour and texture of produce and are difficult to remove completely.

With an eye on commercial-scale application, the team is now preparing to file a patent for their hydrogel technology.