Cellulose nanofibril composite films from jute and flax fibers for fruit preservation: Enhanced barrier properties due to abundant physical interwinding

Due to their abundance and biodegradability, cellulose nanofibrils (CNFs) have been increasingly used in food packaging, but there are still some limitations for the development and industrial application of CNF-based packaging films, such as low water resistance and high manufacturing costs. In response to these issues, we developed a simple and sustainable strategy to produce cost-effective and multifunctional CNF-based composite films from bast fibers. CNFs were directly isolated from bast fibers via ball milling and high-pressure homogenization and then the long CNFs derived from flax fibers (FCNFs) were mixed with the short CNFs derived from jute fibers (JCNFs); the resultant JCNF−FCNF film exhibited enhanced barrier properties to oxygen (oxygen permeability of 1310 cm 3 ∙μm/m 2 ∙day∙atm) and water vapor (water vapor permeability of 5399 g∙μm/m 2 ∙day∙kPa) and superior antioxidant, UV blocking, water-resistant and mechanical properties. The high barrier properties of JCNF−FCNF film were mainly attributed to the abundant physical interwinding between mixed CNFs as well as the natural hydrophobicity of residual lignin in the film. Compared with both neat JCNF and neat FCNF coatings, the JCNF−FCNF coating was more effective in delaying browning of banana peels. This work offers a novel strategy to fabricate sustainable CNF-based composite films for fruit preservation.