Biobased coatings composed of xylans, cellulose nanofibers, and ionic liquids for the fabrication of multifunctional coated papers for food packaging

Conventional plastic coatings used in paper packaging materials raise significant concerns due to their fossil-based origin, limited recyclability, and biodegradability. Additionally, these coatings typically lack relevant functionalities. In response to these challenges, in this study, multifunctional biobased paper coatings, displaying hydrophobicity and antioxidant and antibacterial activities, are developed for the first time, by combining xylans, cellulose nanofibers, and two ionic liquids, namely cholinium dodecanoate and dicholinium ellagate. The obtained coated papers show improved hydrophobicity, with water contact angles reaching values up to 129.2° and water absorption of up to 21.4 g·m −2 . The coated papers further exhibit significant antioxidant capacity, with DPPH radical scavenging activity of 90.7%, and antibacterial activity, with a 1.8 log CFU·mL −1 reduction ( in vitro ) against a methicillin-resistant Staphylococcus aureus strain. Additionally, the good mechanical properties of the papers are maintained. As a proof-of-concept, the coated papers effectively delay browning and pH variations of fresh-cut apples stored over 7 days and are able to contain non-acidic aqueous liquids for up to 24 h without leakages, highlighting their suitability for food-contact applications. Finally, migration tests confirmed that these biobased coated papers comply with EU safety requirements for contact with hydrophilic, alcoholic, and lipophilic foods, as well as water in oil emulsions, under long-term storage at ambient, refrigerated, or frozen conditions, and even for short-term contact at elevated temperatures. These results confirm the potential of the developed biobased coatings as simple, effective, and sustainable alternatives for the fabrication of multifunctional paper-based packaging materials.