Nanocomposite starch-based films containing silver nanoparticles synthesized with lemon juice as reducing and stabilizing agent

Abstract

Silver nanoparticles (AgNP L) synthesis using the active compounds of lemon juice was optimized. The obtained nanoparticles were included in starch-based film formulations, studying the relevant properties that condition their application in the packaging area. The optimized conditions for AgNP L’ synthesis were 30 min at 90 °C, which led to the lowest nanoparticle size (5.5 nm) with the highest associated stability (ζ= −29.5 mV) up to 90 days. Nanocomposite films resulted with an orange tone that increased with AgNP L concentration (14.3–143 ppm). Water vapor permeability decreased while tensile mechanical resistance increased up to an aggregate of 71.5 ppm of AgNP L, indicating the nanoparticles’ reinforcement of the polymer matrix. Besides, the citric acid content provided by lemon juice also affected the starch-based relevant film properties. Regarding antimicrobial capacity, a synergic effect between active compounds of lemon juice and silver nanoparticles was evidenced, being Salmonella spp. the most sensitive bacteria.