Flexible thermoplastic starch films functionalized with copper particles for packaging of food products

Abstract

Biodegradable films based on thermoplastic corn starch (TPS) and copper particles with antimicrobial capacity were developed. Copper nanoparticles (Cu) and silica coated copper microparticles (Si-Cu) in the range of 0.25 to 5% were used. Composite films were obtained by melt-mixing and subsequent thermo-compression. Particles distribution within TPS matrix and the presence of some pores and cracks, induced by Si-Cu particles, was evaluated by SEM. The presence of both fillers gave composite films a brown pigmentation and decreased their transparency; these effects were more pronounced at higher particles concentrations. Regarding mechanical properties, copper particles at 1 and 5% acted as reinforcing agents increasing the maximum tensile strength but their presence lead to a decrease in elongation at break, affecting films ductility. Composites inhibited the growth of Gram+ and Gram-bacteria, demonstrating their antimicrobial capacity. Copper effectively migrated to a simulant of aqueous foods and naked particles concentration in the simulant medium resulted higher than the minimum inhibitory concentration for bacteria. The characteristics and properties of developed composite films make them an interesting material for food primary packaging, mainly for meat fresh products.

Effect of food simulants on stability of copper oxide in bionanocomposite food packaging film

“…7,8 It has been used in recent studies to improve mechanical properties and resistance to water vapour permeability as well as enhance antimicrobial activity in biopolymers. 9,10 Aforementioned research on CuO nanocomposite has primarily focused on how to improve the mechanical properties, barrier properties, ultraviolet light stability, and antimicrobial activities of those copper nanocomposites, while migration studies have been partially discussed to support the possibility of food packaging. Moreover, previous research on copper migration behaviour was conducted on petroleum-based and non-biodegradable plastics that have different properties from biodegradable plastics.…”

“…Copper oxide nanoparticle (CuONP) is one potent material due to its broad spectrum of antimicrobial properties including fungi, viruses, and other food poisoning bacteria 7,8 . It has been used in recent studies to improve mechanical properties and resistance to water vapour permeability as well as enhance antimicrobial activity in biopolymers 9,10 …”

Supercritical CO2 Impregnation of Thymol in Thermoplastic Starch-Based Blends: Chemico-Physical Properties and Release Kinetics

“…This relates to packages containing additives that maintain or extend food quality or shelf-life and therefore contribute to the reduction in spoilage, food waste, food recalls, and foodborne illness outbreaks [ 10 ]. There are several reports on the preparation of TPS-based materials with bioactive components by conventional methods for the development of active food packaging [ 4 , 7 , 8 , 11 , 12 ]. These reports include the addition of watermelon rind extract to a water solution at 70 °C before solvent casting [ 4 ], the incorporation of TiO 2 nanoparticles by extrusion at 165 °C [ 7 ], and the addition of copper particles by thermocompression at 140 °C [ 12 ].…”

“…There are several reports on the preparation of TPS-based materials with bioactive components by conventional methods for the development of active food packaging [ 4 , 7 , 8 , 11 , 12 ]. These reports include the addition of watermelon rind extract to a water solution at 70 °C before solvent casting [ 4 ], the incorporation of TiO 2 nanoparticles by extrusion at 165 °C [ 7 ], and the addition of copper particles by thermocompression at 140 °C [ 12 ]. However, one of the methods that proved to be more efficient for the development of advanced materials is supercritical solvent impregnation (SSI).…”

Sustainable polymer composites: functionality and applications

“…As an important biopolymer from biomass, starch can be converted into so-called "thermoplastic starch" and has been extensively studied for materials applications [5][6][7] and especially for food packaging [8,9]. In this special collection, Villar et al (UNS, UBA, and UNLu, Argentina) [10] demonstrated the antimicrobial capacity of corn starch-based films containing copper (Cu) particles (DOI: https:// doi. org/ 10.…”