Vegetable Lignocellulosic Residues and Chitosan as Valuable Resources in the Superabsorbent Bio-aerogel Development for Food Conservation

Abstract

Superabsorbent bio-aerogels were developed from TEMPO-oxidized cellulose nanofibers (isolated from vegetable lignocellulosic residues) and two different commercial chitosan reactants (low and high molecular weight) by polyelectrolyte complex formation at room temperature. The materials were designed with the aim to provide useful, bio-based, and environmentally friendly food packaging supplies able to successfully replace those currently used that are made of synthetic and non-biodegradable polymers. Three different thickness values were considered, and two different aging times were employed, thus leading to twelve different bio-aerogel samples. Remarkably, no crosslink agents nor organic solvents were used. The bio-aerogel’s components were strongly interacting through hydrogen bonding and electrostatic interactions, leading to highly porous and stable materials able to absorb high amounts of water and soybean oil. Then, the specific tests to visualize the material’s potential use as food absorbent pads showed the following: (i) they were able to absorb simulated food exudates under a specific pressure in higher quantities (≈4000%) than some commercial pads (≈1600%); (ii) the materials have low to moderate antibacterial activities exposing better reduction effectiveness for Listeria monocytogenes than for Salmonella typhimurium; and (iii) the antioxidant properties were in general low. In the light of all the results achieved, the bio-aerogels prepared from H-CH with an aging time of 24 h and whose thickness was around 2.1 mm (H-10g-24) were selected as the most appropriate for the desired application.