CHARACTERIZATION OF EDIBLE FILMS OBTAINED FROM BIOPOLYMERS NANO EMULSIFIED BY ULTRASOUND

VASCO, M. F.; GAMBOA SANTOS J.; CAMPAÑONE, L.A.

Conferencia; 34th EFFoST International Conference 2020; 2020

In response to urgent environmental needs, packaging materials that can be eaten with food such as biodegradable films that cover fruits and vegetables have emerged. With the aim to investigate edible coating formulations, this study focused on to characterization of nano-emulsions based on biopolymers of carboxymethylcellulose, cassava-starch and calcium-alginate, using commercial sunflower oil as a lipid agent and Tween-20 as an emulsifier. The nano-emulsions, obtained after a sonication step, were verified through their particle size and characterized through their rheological behaviour. Subsequently, the nano-emulsified films (ECMC, ECS and EALG) were characterized by studying the compounds interaction through Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD) and the surface morphology was analysed by microscopy (SEM). The results obtained were compared with control films, without adding oil and avoiding the sonication step (CMC, CS and ALG). A significant decrease in the viscosity for ECMC and ECS formulations was recorded after sonication treatment and compared to control samples, with the exception of EALG, whose viscosity was very low but similar to that obtained for ALG films. The FTIR and XRD spectra showed interactions between the compounds of ECMC and ECS samples since new peaks appeared and the crystallinity of the nano-emulsified films changed. However, EALG did not show significant variations with respect to ALG in terms of displacement, generation of new bands or changes in the size of the crystalline domain, thus it can be inferred that no interactions were generated between alginate salt and oil in the nano-emulsion. The ECS nano-emulsified films presented a more uniform distribution of oil droplets throughout the film along with an adequate nano-emulsion stability. Taking into account the results obtained, the biodegradable film based on a cassava starch emulsion (ECS) was considered to be a promising alternative to be used as an edible film or coating for food preservation.