CELLULOSE NANOFIBERS: REINFORCING AND STABILIZING MATERIAL FOR PICKERING EMULSIONS IN FILM-FORMING MATRICES

There is global concern about the serious environmental problem resulting from the large accumulation of packaging waste due to the use of packaging based on non-biodegradable petroleum polymers. Therefore, the use of packaging based on natural biopolymers is an alternative, although they do not have good water barrier properties (WPV) and mechanical resistance to the films. Therefore, the use of cellulose nanofibers (CNF) has attracted attention as a reinforcement system in sustainable films/coatings to improve the useful life of products, presenting advantages such as natural abundance, green technology, and biodegradability. Furthermore, the incorporation of Pickering emulsions (PE) into a film-forming matrix aims to improve the barrier properties of the films. Therefore, this work studied the effect of CNF as a reinforcing material and/or also as a PE stabilizer within the film-forming matrix. Pectin films (4 g/100 g of FM), with addition of PE and/or CNF, were produced by the casting method. The incorporation of CNFs into the films reduced the WPV and created a more hydrophobic film, agreeing with the water contact angle results. Upon the addition of PE, an increase in WPV was observed, which can be explained by the cavities in the structure observed in the microstructure of the films. An improvement in the elasticity of films (PE) was also observed due to the fact that the oil can act as a plasticizer when added to hydrocolloid-based films. The films turned yellow with the addition of PE and CNF, which caused an increase in the opacity. Regarding exposure to UV and visible rays, the films with PE and PE/CNF presented a complete UV barrier and in visible light where the transmittance values were 10 and 5%, respectively. Therefore, we can see that the addition of CNFs and PE are very promising in improving the properties of biopolymeric films.