Nanotechnology used in the synthesis of nanoparticles has attracted great interest in the field of food packaging. It promises the development of food packages with upgraded properties that helps in prolonging the shelf life of food products. This review presents the most commonly used nanoparticles in food packaging, the significant changes they cause in the properties of packaging material, and the commercially available nano-based packaging materials. Nanoparticles are used in the development of improved packaging, active packaging, and intelligent packaging which helps in the maintenance of food quality and traceability during the supply chain. Nanoparticles possess antimicrobial activity, oxygen scavenging ability, UV impermeability, and various other properties that make them valuable for their application in the preparation of nanocomposites. The large surface area to volume ratio sometimes becomes the reason for nanoparticle toxicity so it is important to study their migration and interaction with polymer matrix while developing packaging materials. Schematic representation of active packaging. • Nanotechnology in the development of food packaging has been discussed. • Organic, inorganic, and combined nanoparticles are used to prepare improved active and intelligent food packaging. • Nanoparticle provides improved physical and antimicrobial properties thus, helps in prolonging the shelf life of food. • The migration and toxicity of nanoparticles need to be studied during their incorporation in food packaging. 

Application of nanotechnology in food packaging: Pros and Cons

A new nanomaterial or nano-filler in the form of multiwalled carbon nanotube-zinc oxide (MWCNT-ZnO) was synthesized for the purpose of modifying poly(butylene adipate-co-terephthalate) (PBAT) and its derivative (modified PBAT or MPBAT) through a melt-blending method (MPBAT was obtained by introducing maleic anhydride groups into PBAT). The effect of the new nano-filler on the properties of resultant nanocomposites was determined from the characterization of mechanical properties, morphology, crystallinity, thermal stability, barrier properties, hydrophilicity, conductivity, antibacterial property, and biodegradability. The results showed that MPBAT nanocomposites had stronger mechanical properties, better barrier properties, and higher electrical conductivity than PBAT nanocomposites. Scanning electron microscopy illustrated that MWCNT-ZnO had better compatibility with MPBAT than with PBAT. At 0.2% MWCNT-ZnO, the MPBAT/MWCNT-ZnO nanocomposite film exhibited the greatest mechanical properties (17.74% increase in tensile strength, 22.17% in yield strength, and 14.29% in elongation at break). When the MWCNT-ZnO content was 0.4%, the nanocomposite film demonstrated the best water vapor barrier ability (an increase of 30.4%). The MPBAT/MWCNT-ZnO film with 0.6% MWCNT-ZnO turned out to have the best oxygen barrier performance (an increase of 130% relative to pure PBAT). It was shown from the results of antibacterial evaluation that the new nanomaterial could impart PBAT and MPBAT with antibacterial activity. The biodegradability tests indicated that an MWCNT-ZnO content of 0.2% could slightly reduce the biodegradability, and when the content was higher than 0.2%, the weight loss rate would increase.

Barrier performance and biodegradability of antibacterial poly(butylene adipate-co-terephthalate) nanocomposites reinforced with a new MWCNT-ZnO nanomaterial.

Photodegradation and oxidation are major causes of the deterioration of food, resulting in darkening, off-flavors, and nutrient deficiency. To reduce this problem, novel functional polymeric materials are being developed to retain food’s light sensitivity. Nanofillers are also used in a polymeric film to produce effective UV blockings and oxygen barrier coatings so that the degradation of the food can be delayed, thereby increasing the shelf life. For this purpose, polyvinyl alcohol coatings were prepared by the incorporation of ZnO nanoparticles. Polyvinyl alcohol is a naturally excellent barrier against oxygen, and the addition of ZnO particles at the nanoscale size has demonstrated effective UV blocking capabilities. In this work, the hydrothermal technique is used to produce ZnO nanoparticles, and these produced particles are then incorporated into the polyvinyl alcohol to produce thin films. These films are characterized in terms of the compositional, macroscopic, microscopic, and optical properties via X-ray diffraction (XRD), FTIR, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), as well as UV–VIS spectroscopy. ZnO nanoparticles at different concentrations were incorporated into the PVA solution, and the films were processed via the blade coating method. With the addition of ZnO, the oxygen transmission rate (OTR) of pure PVA was not altered and remained stable, and the lowest OTR was recorded as 0.65 cm3/m2·day·bar. Furthermore, the addition of ZnO increased the water contact angle (WCA) of PVA, and the highest WCA was recorded to be around more than 70°. Due to this, water permeability decreased. Additionally, PVA/ZnO films were highly flexible and bendable and maintained the OTR even after going through bending cycles of 20K. Furthermore, the addition of ZnO showed a significant UV blocking effect and blocked the rays below a wavelength of 380 nm. Finally, the optimized films were used for packaging applications, and it was observed that the packaged apple remained fresh and unoxidized for a longer period as compared with the piece of apple without packaging. Thus, based on these results, the PVA/ZnO films are ideally suited for packaging purposes and can effectively enhance the shelf life of food.

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UV Blocking and Oxygen Barrier Coatings Based on Polyvinyl Alcohol and Zinc Oxide Nanoparticles for Packaging Applications

The present paper deals with design of silicon doped PS/SnS2 new composites to use in different nano-semiconductors devices include optic, electronic, photonic and electric approaches with individual characteristics contain few cost, high corrosion resistance, lightweight and good optical, thermal and electronic properties. Using the density functional theory (DFT), some of the electronic (energy band structure, density of states) and electronic characteristics of PS/SnS2/Si composites. S-vacancy could lead to strong n doping for the original SnS2, which largely influences its electronic structure. The obtained results indicated to the PS/SnS2/Si composites may be used for various optoelectronics devices with low cost and high flexibly. The energy band gap PS/SnS2/Si composites was found (Eg = 0.19 eV) which make it can be suitable in various nano-semiconductors devices. The calculated density of states (DOS) may interpret this magnitude of energy gap.

Design and Tailoring the Optical and Electronic Characteristics of Silicon Doped PS/SnS2 New Composites for Nano-Semiconductors Devices

The present work aims to investigate the structure, spectral and electronic characteristics of (polystyrene-boron-silicon) new structures by density functional theory (DFT) with the hybrid functional B3LYPat Gaussian 09 package of programs. The designed structures of silicon doped PS/B have huge applications in various fields like solar cells, photovoltaic cell, diodes, electronics gates, transistors, sensors and other low cost and lightweight renewable and electronics fields. The structure characteristics included the ionization potentials, electron affinity, energy, and energy gap. The results of structure, electronics and optical characteristics for PS/B/Si structures indicated that the designed structures have energy gap (0.77 eV) and wide range of absorption at visible and IR regions. Finally, studied characteristics showed that the PS/B/Si structures can be useful in various electronics, optics, renewable fields.

Exploring the Design, Optical and Electronic Characteristics of Silicon Doped (PS-B) New Structures for Electronics and Renewable Approaches

Poly(vinyl alcohol) (PVA) is a synthetic and promising film-forming polymer that is usually used in packaging applications In this study, PVA nanocomposite films with varying amounts of zinc oxide-doped multiwalled carbon nanotubes (MWCNTs-ZnO) were prepared The tensile strength of the nanocomposite films was 116% higher than that of the PVA film The thermal stability, water vapor transmission rate, hydrophobicity, and antibacterial activity of the nanocomposite films were better than those of pure PVA Tests on water loss in vegetables at room temperature revealed that the vegetable wrapped in packaging films could keep more water for more than 4 days Tests on the shelf life of chicken meat packed in films suggested that the growth of natural microorganisms in raw chicken kept in the preservation storage of the refrigerator could be inhibited for at least 36 h The findings of this study indicated that nanocomposite MWCNTs-ZnO/PVA films with good transparency had great potential applications in food packaging

Antibacterial nanocomposite films of poly(vinyl alcohol) modified with zinc oxide-doped multiwalled carbon nanotubes as food packaging

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Two new chromone derivatives from the rhizosphere soil fungus Ilyonectria robusta.

A three-layer superhydrophobic coatings inspired by human scalp structure with excellent anti-reflection and durable effects for photovoltaic applications

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Yu-Ting Zheng

Papers

Antibacterial nanocomposite films of poly(vinyl alcohol) modified with zinc oxide-doped multiwalled carbon nanotubes as food packaging

Two new chromone derivatives from the rhizosphere soil fungus Ilyonectria robusta.

A three-layer superhydrophobic coatings inspired by human scalp structure with excellent anti-reflection and durable effects for photovoltaic applications

Pseudocercones A-C, three new polyketide derivatives from the endophytic fungus Pseudocercospora sp. TSS-1.