Development and characterization of alginate-based edible film from Sargassum fluitans incorporated with silver nanoparticles obtained by green synthesis

The high susceptibility to deterioration and diseases during the supply chain and/or during the storage of fresh products is a problem in the industry, and edible films are proposed as efficient methods to preserve its quality. The objective was to obtain and characterize silver nanoparticles (AgNPs) and determine their effect on optical, barrier and mechanical properties of alginate-based films. The alginate was extracted from Sargassum fluitans. AgNPs were obtained by green synthesis using Gliricidia sepium. The UV–Vis and dynamic light scattering (DLS) were used to characterize the AgNPs. The antifungal activity of AgNPs was investigated using several fungal strains. Films were formulated by using 2 and 3% alginate, as well as 0, 1, and 2 mg of AgNPs per mL of formulation, with glycerol as a plasticizer. A randomized experimental design was used to test the effect to alginate and the AgNPs concentrations. The results were analyzed by an ANOVA test (p < 0.05). The films were characterized by water vapor permeability (WVP), mechanical properties, opacity, color, glass transition and melting temperatures, as well as scanning electron microscopy (SEM) and energy dispersive X-Ray (EDS) spectroscopy. WVP, optical and mechanical properties of the films were influenced statistically with alginate and AgNPs concentrations. The PVA values varied between 0.83 and 1.74 g mm h−1 kPa−1 m−2. The results demonstrated that films made with higher alginate and AgNPs concentrations exhibited higher tensile strength (20.35 MPa) and elongation at break (74.56%). The AgNPs showed percentages of growth inhibition higher than 79% in all fungal strains tested. The films formulated had attractive properties that are used to extend shelf life of foods.