GA used as oxygen scavenger in new bio-based packaging

Researchers at the Technical University in Munich worked alongside The Fraunhofer Institute to produce a multilayer bio-based packaging film. They used gallic acid (GA) and sodium carbonate as an oxygen scavenger, which protects oxygen-sensitive food products in the packaging process. This could be a suitable solution for the packaging of food products with high water activity in order to ensure the safety of the product and extend shelf life.

The researchers investigated the film surface colour as well as oxygen absorption at different relative humidities (RH) and temperatures, and compared the oxygen absorption of powder, monolayer films and multilayer films. Although the films were originally a brownish-red colour, under humid conditions this colour became a greenish-black during oxygen absorption.

The team observed a maximum absorption capacity of 447 mg O₂/g GA at 21°C and 100% RH. They found that incorporating GA into a polymer matrix reduced the rate of oxygen absorption because the polymer acted as a barrier to oxygen and the diffusion of water vapour.

Temperature also had an effect on the initial absorption rate of the multilayer films; the corresponding activation energy was 75.4 kJ/mol. Higher RH significantly increased the oxygen absorption rate.

The results demonstrate the production and properties of a bio-based multilayer packaging film with GA as the oxygen scavenger.