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The quest for sustainable and functional food packaging materials has led researchers to explore biopolymers such as pullulan, which has emerged as a notable candidate for its excellent film-forming and anti-fogging properties. This study introduces an innovative anti-fog coating by combining pullulan with poly (acrylic acid sodium salt) to enhance the display of packaged food in high humidity environments without impairing the sealing performance of the packaging material—two critical factors in preserving food quality and consumers' acceptance. The research focused on varying the ratios of pullulan to poly (acrylic acid sodium salt) and investigating the performance of this formulation as an anti-fog coating on bioriented polypropylene (BOPP). Contact angle analysis showed a significant improvement in BOPP wettability after coating deposition, with water contact angle values ranging from ~60° to ~17° for formulations consisting only of poly (acrylic acid sodium salt) (P0) or pullulan (P100), respectively. Furthermore, seal strength evaluations demonstrated acceptable performance, with the optimal formulation (P50) achieving the highest sealing force (~2.7 N/2.5 cm) at higher temperatures (130 °C). These results highlight the exceptional potential of a pullulan-based coating as an alternative to conventional packaging materials, significantly enhancing anti-fogging performance. [ABSTRACT FROM AUTHOR]

A new molecularly imprinted electrochemical sensor was proposed to determine 4,4′-methylene diphenyl diamine (MDA) using molecularly imprinted polymer–multiwalled carbon nanotubes modified glassy carbon electrode (MIP/MWCNTs/GCE). GCE was coated by MWCNTs (MWCNTs/GCE) because of their antifouling qualities and in order to improve the sensor sensitivity. To make the whole sensor, a polymeric film made up of chitosan nanoparticles was electrodeposited by the cyclic voltammetry method on the surface of MWCNTs/GCE in the presence of MDA as a template. Different parameters such as scan cycles, elution time, incubation time, molar ratio of template molecules to functional monomers, and pH were optimized to increase the performance of the MIP sensor. With a detection limit of 15 nM, a linear response to MDA was seen in the concentration range of 0.5–100 µM. The imprinting factor (IF) of the proposed sensor was also calculated at around 3.66, demonstrating the extremely high recognition performance of a MIP/MWCNT-modified electrode. Moreover, the sensor exhibited good reproducibility and selectivity. Finally, the proposed sensor was efficiently used to determine MDA in real samples with satisfactory recoveries ranging from 94.10% to 106.76%. [ABSTRACT FROM AUTHOR]

• Oxygen is regarded as the main factors of degradation for several food products. • Oxygen barrier materials represent an important target for the food industry. • We overview the development of oxygen barrier coatings based on nanotechnology. • Most relevant examples of nanostructured and nanocomposite coatings are presented. • Open issues that hinder the full market penetration of nano-coatings are discussed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • TDA is a toxic compound possibly migrating from packaging materials to foods. • A new electrochemical sensor has been designed for the selective determination of TDA. • Chitosan, AuNPs, and MWCNTs have been used to achieve high selectivity and sensitivity. • The modified GCE has shown excellent stability and analytical performance. • Tests on real food packaging materials have shown the great potential of this new device. Abstract This work describes the development of a modified glassy carbon electrode (GCE) for the selective determination of 2,4-diaminotoluene (TDA), a primary aromatic amines (PAAs) that can be formed in food packaging materials including aromatic polyurethane (PU) adhesives. The electrode's surface was modified with multi-walled carbon nanotubes (MWCNTs), MWCNTs in chitosan (CS), and gold nanoparticles (AuNPs). The highest current response was achieved with AuNPs/MWCNTs-CS/GC electrodes, which exhibited an oxidation peak of 9.87 μA by cyclic voltammetry (CV), compared with 1.39 μA of the bare GCE. A detection limit of 35 nM was estimated by amperometry experiments. The oxidation of TDA was strongly dependent on the pH of the medium, having maximum sensitivity at pH ∼ 7. From a mechanistic point of view, the diffusion coefficient of TDA (D = 6.47 × 10−4 cm2 s−1) and the number of electrons (n ≈ 2) involved in the catalytic oxidation of TDA at the surface of the AuNPs/MWCNTs-CS/GCE were determined. The practical utility of this nanocomposite modified electrode was demonstrated by migration studies from conventional food packaging materials. [ABSTRACT FROM AUTHOR]

Background Intelligent packaging is the newest technology within the food packaging field. Even though this technology is still growing and not fully commercially viable, it has enormous potential to improve the safety, quality, and traceability of food products, as well as its convenience for consumers. Scope and approach This paper first describes both the technical aspects and commercial applications of the most representative intelligent technologies—indicators, data carriers, and sensors—with special focus on systems and devices that are directly integrated into the package. Secondly, to provide useful guidelines for future research in the field, the paper discusses some important aspects that still hinder the full exploitation of intelligent technology within the food packaging industry. Key findings and conclusions Future research needs to consider some important aspects in order to make intelligent systems commercially viable, such as cost, consumers' acceptance and confidence, regulatory aspects (e.g., labeling), and multifunctionality. [ABSTRACT FROM AUTHOR]

Primary aromatic amines (PAAs) are substances that can be transferred from food packaging materials into foodstuffs and are “possibly carcinogenic to humans”. The formation of PAAs from multilayer packaging materials consisting of aromatic polyurethane (PU) adhesives occurs from the reaction between residual isocyanic monomers that have migrated to the surface of the inner layer of the package and water molecules making contact with the same plastic surface. However, for foods subjected to thermal treatments, an alternative formation of PAAs should also be taken into consideration. Due to the detrimental effect of the temperature, some secondary bonds (namely allophanate and biuret bonds) displaced on the main PU backbone may be disrupted, originating neo-formed isocyanic monomers. The migration of these monomers from the adhesive layer across the inner sealing film can lead to PAAs as soon as they come into contact with the water molecules of the liquid or high a w packaged food. Although the existence and the mechanisms of the formation of allophanate and biuret linkages during the polymerization process with poly-isocyanates has been known for a long time, the negative impact on public health possibly arising from the migration of the neo-formed isocyanic monomers into the foods during thermal treatments seems to have not been fully perceived, with special regard to preservative heat treatments such as pasteurization and sterilization. In this viewpoint article, after covering both chemical and physical aspects involved in the formation of PAAs, especially in thermally-treated PU-based multilayer packaging materials, we have stressed the necessity for a more careful consideration of the risks associated with the potential formation of PAAs, in a first instance by strict compliance with the provisions included in the current European legislation. The necessity for alternative analytical tools for the PAAs quantification is also highlighted. [ABSTRACT FROM AUTHOR]

Fundamental physical behaviors of materials at the nanoscale level are crucial when local aspects govern the macroscale performance of nanocomposites, e.g., interface and surface phenomena. Because of the increasing interest in biopolymer nanocomposite coatings for many different applications (e.g., optical devices, displays/screens, and packaging), this work investigates the potential of nanoindentation as a method for clarifying the interplay between distinct phases (i.e., organic and inorganic) at local level in thin biopolymer films loaded with nanoparticles. The nanomechanical features of pullulan nanocomposite coatings laid on polyethylene terephthalate (PET) were quantified in terms of elastic modulus ( E ), hardness ( H ), and creep ( C ) through an instrumented indentation test composed of a loading-holding-unloading cycle. Colloidal silica (CS) and cellulose nanocrystals (CNCs) were used as spherical and rod-like nanoparticles, respectively. An overall reinforcing effect was shown for all nanocomposite coatings over the pristine (unfilled) pullulan coating. A size effect was also disclosed for the CS-loaded surfaces, with the highest E value recorded for the largest particles (8.19 ± 0.35 GPa) and the highest H value belonging to the smallest ones (395.41 ± 25.22 MPa). Comparing CS and CNCs, the addition of spherical nanoparticles had a greater effect on the surface hardness than cellulose nanowhiskers (353.50 ± 83.52 MPa and 321.36 ± 43.26 MPa, respectively). As for the elastic modulus, the addition of CS did not provide any improvement over both the bare and CNC-loaded pullulan coatings, whereas the coating including CNCs exhibited higher E values ( p  < .05). Finally, CS-loaded pullulan coatings were the best performing in terms of C properties, with an average indentation depth of 16.5 ± 1.85 nm under a load of ∼190 μN. These results are discussed in terms of local distribution gradients, surface chemistry of nanoparticles, and how nanoparticle aggregation occurred in the dry nanocomposite coatings. [ABSTRACT FROM AUTHOR]

In this work, we present the development of bionanocomposite coatings on poly(ethylene terephthalate) (PET) with outstanding oxygen barrier properties. Pullulan and graphene oxide (GO) were used as main polymer phase and nanobuilding block (NBB), respectively. The oxygen barrier performance was investigated at different filler volume fractions (φ) and as a function of different relative humidity (RH) values. Noticeably, the impermeable nature of GO was reflected under dry conditions, in which an oxygen transmission rate (OTR, mL·m-2·24 h-1) value below the detection limit of the instrument (0.01 mL·m-2·24 h-1) was recorded, even for ' as low as 0.0004. A dramatic increase of the OTR values occurred in humid conditions, such that the barrier performance was totally lost at 90% RH (the OTR of coated PET films was equal to the OTR of bare PET films). Modelling of the experimental OTR data by Cussler's model suggested that the spatial ordering of GO sheets within the main pullulan phase was perturbed because of RH fluctuations. In spite of the presence of the filler, all the formulations allowed the obtainment of final materials with haze values below 3%, the only exception being the formulation with the highest loading of GO (φ ≈ 0.03). The mechanisms underlying the experimental observations are discussed. [ABSTRACT FROM AUTHOR]

The current work aims to produce nanoparticle-infused starch-based bioactive thermoplastic packaging films. The FeO and ZnO nanoparticles were examined to be potential active ingredients for the production of nanoparticle-infused bioactive thermoplastic packaging films. The bio-thermoplastic films infused with FeO and ZnO nanoparticles showed high oxygen scavenging and antimicrobial activity, respectively. Consecutively, both films were combined to form a double-layer Nano-Biothermoplastic packaging system for food preservation. The distribution and diffusion of nanoparticles in starch-based films were examined to be influenced by the amorphous character of starch and the swelling index of the film, respectively. The amorphous property of starch molecules showed a masking effect on the crystalline characteristics of nanoparticles in Nano-Biothermoplastic films. The diffusion of nanoparticles from the Nano-Biothermoplastic packaging system was found to influence the microbial, chemical, and color characteristics of mutton and chicken meat stored at 4 °C. [Display omitted] • The FeO and ZnO Nps were found to be potential active ingredient for food packaging. • The amorphous regions of starch were found to immobilize the FeO and ZnO Nps. • The crystalline nature of Nps was masked by amorphous regions of starch molecules. • The double layer Nano-Biothermoplastic films were identified as potential food package. [ABSTRACT FROM AUTHOR]