Active composite starch films containing green synthetized silver nanoparticles

Abstract

The aims of this work were to couple both the silver nanoparticles (AgNPs) synthesis, and filmogenic suspensions preparation, to characterize the obtained AgNPs and the derived nanocomposite films studying their antimicrobial capacity and developing an active packaging. One of the new approaches to this work is the use of low concentrations of AgNPs at which no adverse cytotoxic effects have been observed. Nanoparticles were characterized by spectrophotometric techniques and electron microscopy, finding that they are spherical with diameters varying between 5 and 20 nm and detecting the formation of agglomerates. The addition of AgNPs did not affect the filmogenic capacity of gelatinized starch suspension. The content of AgNPs caused a slight increase in film thickness and opacity, keeping the material UV-barrier capacity. A decrease in water vapor permeability with increasing AgNPs concentration was observed. Besides, AgNPs allow the matrix reinforcement, developing a more resistant and tough material, with smooth and homogeneous surfaces, as evidenced by SEM, and maintaining their heat sealing capacity. Nanocomposite films containing AgNPs concentrations greater than 71.5 ppm inhibited the growth of E. coli ATCC and Salmonella spp., which are responsible for most foodborne diseases. However, films containing 143 ppm AgNPs were selected since they better maintained their integrity to microbial attack. These active films were able to extend the shelf-life of fresh cheese samples for 21 days. Thus, it was possible to develop and characterize nanocomposite films based on corn starch and containing AgNPs, which confers them antimicrobial properties.

Physical, mechanical, and antibacterial characteristics of bio‐nanocomposite films loaded with Ag‐modified SiO2 and TiO2 nanoparticles

“…However, its application is restricted because of its weak mechanical strength, hydrophilicity, and lack of water barrier properties (Tang, Zou, Xiong, & Tang, 2008; Torabi & Mohammadi‐Nafchi, 2013). For this reason, blends of starch with other nanomaterials or nanoparticles (NPs) have been considered for packaging applications (Ortega, Giannuzzi, Arce, & García, 2017). The importance of using NPs as fillers is not only improving the mechanical properties of the resulting films, but also increasing the compatibility between mixed components (Angelova, Rangelova, Dineva, Georgieva, & Müller, 2014; Beigmohammadi et al., 2016).…”

Biopolymers-Based Materials Containing Silver Nanoparticles as Active Packaging for Food Applications–A Review

“…A linear increasing tendency was also observed for elongation at break and a linear decreasing tendency for elastic modulus of analysed films [47]. Decreased values of mechanical strength and elastic modulus caused by addition of silver nanoparticles were found by Ortega et al [50] for nanocomposite starch films and by Yoksan et al [51] for chitosan-starch blended films. However, silver nanoparticles did not affect elongation at break, which remained constant, leading to resistant and tough materials.…”

“…Several studies have shown that the addition of silver nanoparticles caused a significant reduction in the water vapour permeability values of biopolymer nanofilms [21,22,24,25,50,55,56,58,59]. The decrease in the water vapour permeability of investigated films was attributed to the distribution of silver nanoparticles as a discontinuous phase in the polymer matrix, which affected lower diffusion of water molecules through the films.…”

“…Similarly, much darker pectin films were also observed due to the incorporation of silver nanoparticles into the polymer matrix [37]. However, Ortega et al [50] obtained colourless nanocomposite starch films, indicating that silver nanoparticles caused a slight increase in film opacity while keeping the UV barrier capacity. Therefore, the colour and opacity of the films could change with the presence and concentration of silver particles, thus affecting the final application for food.…”

Glucose-Reduced Silver Nanoparticles Prepared with Amylose-Sodium Palmitate Inclusion Complexes and Their Dry Storage and Reconstitution

“…Accordingly, there has been considerable research over the past few decades to develop methods for obtaining the smallest size nanoparticles from the reduction of silver nitrate and incorporating these Ag NPs into various consumer products. For example, incorporation of Ag NPs into films or gels of gelatin, chitosan‐konjac glucomannan, starch, dialdehyde starch‐chitosan, and poly(acrylamide) have been described. Ag NPs have also been prepared on knitted cellulose and cotton fabric as well as combined with various polymers to prepare conductive ink and electrically conductive polymer films .…”