Investigation into the role of layered nanoporous modified clays for adsorption/desorption of rosemary essential oil in the gas phase and the ability of this system as an antioxidant and preservation agent in food applications.

Abstract

A new green composite material with antioxidant properties and specific-targeting capabilities was developed using Montmorillonite Clay in modified forms for rosemary essential oil gaseous adsorption without harmful chemicals or excessive heat. The modified clays were tested for their adsorption capabilities, with the sodic clay showing the highest affinity for the essential oil. The study also found that the adsorbed essential oil on sodic clay had the highest antioxidant activity compared to the organic and pillared clays. Adsorption isotherms revealed values of 40, 30, and 18 mg g^-1 for sodic, organic, and pillared clay respectively. To assess the experimental data three models were used: First Order, Second Order, and Intra-particular Diffusion. According to the models' data, the Second Order model fits the experimental results. These results suggest combining modified clays with essential oils can create materials suitable for controlled release systems in food and pharmaceutical applications. Highlights The capacity of gaseous adsorption of REO on sodic, organic, and pillared clays depends essentially on the interaction between the clay's external surface and the essential oil-active molecules. Adsorbed essential oil on clays' surfaces without any direct contact shows an antioxidant activity against DPPH that can be explored in further research concerning food packaging, drug delivery…etc. The desorbed amount of REO is practically less than half of the adsorbed quantity which involves both physisorption and chemisorption interactions.