Biodegradable nanocellulose hydrogels from agricultural waste: Impact of defibrillation on mechanical and antimicrobial properties

Food spoilage, which often leads to food waste, occurs throughout the entire food supply chain, from the upstream to downstream stages of food production. Biobased hydrogels made from cellulose nanofiber (CNF) have emerged as potential materials for extending food shelf-life. Despite this potential, the impact of defibrillation time during the production of CNF on the properties of CNF-based hydrogels (CNF-H) has not been thoroughly investigated. In this study, the defibrillation time of CNF was varied at 50–90 min to examine its effect on both the CNF itself and the resulting hydrogel properties. The findings revealed that longer mechanical defibrillation times significantly reduced the size of the CNF, leading to a denser CNF-H structure. At extended defibrillation times, the diameter of the CNF decreased from 25 to 20 nm, which strengthened the inter- and intramolecular forces between CNF fibers, resulting in a more crystallinity (from 66.64% to 77.51%) and compact hydrogel network. This denser structure reduced water absorption capacity, thereby limiting moisture penetration and decreasing biodegradability. Additionally, the antimicrobial activity of CNF-H, tested after soaking in ethanol, showed enhanced effectiveness against both gram-positive and gram-negative bacteria with increased defibrillation time, all without exhibiting cytotoxic effects.