Structural, mechanical, antioxidant and antibacterial properties of soy protein isolate (SPI)-based edible food packaging films as influenced by nanocellulose (NC) and green extracted phenolic compounds from date palm leaves

Abstract

This study investigated the addition of cellulose nanoparticles (NC) and green extracted phenolic compounds from date palm leaves (DLE) as reinforcing and bioactive agent, respectively, into the soy protein isolate (SPI) edible films. Structural, physiochemical, optical, mechanical, barrier, thermal, and bioactive properties of the films were explored. The incorporation of NC improved the SPI film’s physiochemical, mechanical, and barrier properties but did not show effect on the antioxidant and antibacterial properties. Following the incorporation of DLE in liquid form (DLWE) the film’s antioxidant and antibacterial properties significantly increased but due to the presence of natural deep eutectic solvent (NADES) (plasticizer) all other properties were negatively affected. However, enriching the SPI-NC films with DLE in powder form (DLPE) improved the bioactive properties while maintaining the improved mechanical and barrier properties. These findings indicated that SPI-NC/DLPE films exhibited improvements in the whole performance and provided promising strategy for formulation of biodegradable packaging films. This approach is an effective strategy towards sustainable utilization of unexplored agricultural wastes (date palm leaves derived NC and phenolic compounds) for development of active and environmentally friendly food packaging material.