Properties of active starch-based films incorporating a combination of Ag, ZnO and CuO nanoparticles for potential use in food packaging applications

Nanofillers in Novel Food Packaging Systems and Their Toxicity Issues

Background: Environmental concerns about petroleum-based plastic packaging materials and the growing demand for food have inspired researchers and the food industry to develop food packaging with better food preservation and biodegradability. Nanocomposites consisting of nanofillers, and synthetic/biopolymers can be applied to improve the physiochemical and antimicrobial properties and sustainability of food packaging. Scope and approach: This review summarized the recent advances in nanofiller and their applications in improved food packaging systems (e.g., nanoclay, carbon nanotubes), active food packaging (e.g., silver nanoparticles (Ag NPs), zinc oxide nanoparticles (ZnO NPs)), intelligent food packaging, and degradable packaging (e.g., titanium dioxide nanoparticles (e.g., TiO2 NPs)). Additionally, the migration processes and related assessment methods for nanofillers were considered, as well as the use of nanofillers to reduce migration. The potential cytotoxicity and ecotoxicity of nanofillers were also reviewed. Key findings: The incorporation of nanofillers may increase Young's modulus (YM) while decreasing the elongation at break (EAB) (y = -1.55x + 1.38, R2 = 0.128, r = -0.358, p = 0.018) and decreasing the water vapor (WVP) and oxygen permeability (OP) (y = 0.30x - 0.57, R2 = 0.039, r = 0.197, p = 0.065). Meanwhile, the addition of metal-based NPs could also extend the shelf-life of food products by lowering lipid oxidation by an average of approx. 350.74% and weight loss by approx. 28.39% during the longest storage period, and significantly increasing antibacterial efficacy against S. aureus compared to the neat polymer films (p = 0.034). Moreover, the migration process of nanofillers may be negligible but still requires further research. Additionally, the ecotoxicity of nanofillers is unclear, as the final distribution of nanocomposites in the environment is unknown. Conclusions: Nanotechnology helps to overcome the challenges associated with traditional packaging materials. Strong regulatory frameworks and safety standards are needed to ensure the appropriate use of nanocomposites. There is also a need to explore how to realize the economic and technical requirements for large-scale implementation of nanocomposite technologies.

Surface modified ZnO NPs by betaine and proline build up tomato plants against drought stress and increase fruit nutritional quality

Drought stress is a serious challenge for global food production. Nanofertilizers and nanocomposites cope with such environmental stresses and also increase nutritional contents of fruits. An in vitro experiment was designed to use Zinc Oxide Nanoparticles (ZnO NPs) primed with Proline and Betaine (ZnOP and ZnOBt NPs) at 50 and 100 mg/kg soil against drought stress in Tomato (Solanum lycopersicum) plants. Plant morphological, biochemical, and fruit nutritional quality were accessed. Maximum plant height was observed under the treatment of ZnOP50 (1.09 m) and ZnO 100 (1.06 m). ZnOP and ZnOBt also improved the chlorophyll content up to 86% and 87.16%, respectively. Application of ZnOP NPs also demonstrated maximum tomato yield (204 g tomato/plant) followed by ZnO NPs and ZnOBt NPs. Nanocomposites decreased phenolics and flavonoids contents in drought stressed plants demonstrating the mitigation of oxidative stress. Nanofertilizer also increased the concentration of phenolics and flavonoids in fruits that increased the nutritional contents. Furthermore a significant accumulation of betaine, proline, and lycopene in fruits on nanocomposite treatment made it nutritional and healthy. Lycopene content increased up to 2.01% and 1.23% in presence of ZnOP50 and ZnOP100, respectively. These outcomes validate that drought stress in plant can be reduced by accumulation of different phytochemicals and quenching oxidative stress. The study deems that nano zinc carrying osmoregulators can greatly reduce the negative effects of drought stress and increase nutritional quality of tomato fruits.

Recent advances in protein-polysaccharide based biocomposites and their potential applications in food packaging: A review

This review addresses the current trend of replacing petroleum-based polymers in food packaging with bio-based alternatives, specifically focusing on proteins and polysaccharides. While these biopolymers exhibit excellent film-forming properties and are abundant in nature, their individual use in packaging lacks ideal plastic-like characteristics, especially in terms of mechanical and barrier properties. A recent solution involves the formulation of biocomposites through the reinforcement of one biopolymer with another (e.g., protein with a polysaccharide), significantly enhancing the physical, mechanical, and barrier properties of packaging materials. The review concentrates on the integration of proteins and polysaccharides in biocomposite materials, emphasizing their potential applications in active and intelligent food packaging systems. It covers sources, manufacturing methods, interaction mechanisms, recent developments, perspectives, and opportunities. The exploration extends to practical implementations of these biocomposites in enhancing food quality, safety, and shelf life-a green technological approach contributing to the reduction of food waste and loss.

Carbon dot/g-C3N4-mediated self-activated antimicrobial nanocomposite films for active packaging applications

A novel carbon dot/g-C3N4 nanocomposite (CCN) exhibiting enhanced photocatalytic activity was developed and used as a photoactive nanofiller to construct corn starch/carboxymethyl cellulose (CS/CMC)-based functional films. The morphologies and structures of the CCN-CS/CMC composite films were investigated with scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The effects of the CCN on the physicochemical properties and antibacterial activities of the films were analyzed. The properties of the films were optimized with the addition of CCN (0.20 mg/mL), and the tensile strength of the film was increased to 11.9 MPa and the water contact angle was increased to 103.39°. The optimal active film showed > 99.9 % antibacterial efficiencies against Escherichia coli and Staphylococcus aureus under visible light and prolonged the shelf lives of bananas for more than four days compared to the 4-day shelf life of the control. This work provides a novel route for developing antimicrobial active packaging.

Enhanced antibacterial properties of polyvinyl alcohol/starch/chitosan films with NiO-CuO nanoparticles for food packaging

Packaging is very important to maintain the quality of food and prevent the growth of microbes. Therefore, the use of food packaging with antimicrobial properties protects the food from the growth of microorganisms. In this study, antibacterial nanocomposite films of polyvinyl alcohol/starch/chitosan (PVA/ST/CS) together with nickel oxide-copper oxide nanoparticles (NiO-CuONPs) are prepared for food packaging. NiO-CuONPs were synthesized by the co-precipitation method, and structural characterization of nanoparticles (NPs) was carried out by XRD, FTIR, and SEM techniques. Composites of PVA/ST/CS, containing different percentages of NPs, were prepared by casting and characterized by FTIR and FESEM. The mechanical properties, diffusion barrier, and thermal stability were determined. The nanoparticles have a round structure with an average size of 6.7 ± 1.2 nm. The cross-section of PVA/ST/CS film is dense, uniform, and without cracks. In the mechanical tests, the addition of NPs up to 1% improved the mechanical properties (TS = 31.94 MPa), while 2% of NPs lowered TS to 14.76 MPa. The fibroblast cells toxicity and the films antibacterial activity were also examined. The films displayed stronger antibacterial effects against Gram-positive bacteria (Staphylococcus aureus) compared to Gram-negative bacteria (Escherichia coli). Furthermore, these films have no toxicity to fibroblast cells and the survival rate of these cells in contact with the films is more than 84%. Therefore, this film is recommended for food packaging due to its excellent mechanical and barrier properties, good antibacterial activity, and non-toxicity.

Natural polysaccharides and proteins-based films for potential food packaging and mulch applications: A review

Conventional nondegradable packaging and mulch films, after reaching the end of their use, become a major source of waste and are primarily disposed of in landfills. Accumulation of non-degradable film residues in the soil leads to diminished soil fertility, reduced crop yield, and can potentially affect humans. Application of degradable films is still limited due to the high cost, poor mechanical, and gas barrier properties of current biobased synthetic polymers. In this respect, natural polysaccharides and proteins can offer potential solutions. Having versatile functional groups, three-dimensional network structures, biodegradability, ease of processing, and the potential for surface modifications make polysaccharides and proteins excellent candidates for quality films. Besides, their low-cost availability as industrial waste/byproducts makes them cost-effective alternatives. This review paper covers the performance properties, cost assessment, and in-depth analysis of macromolecular structures of some natural polysaccharides and proteins-based films that have great potential for packaging and mulch applications. Proper dissolution of biopolymers to improve molecular interactions and entanglement, and establishment of crosslinkages to form an ordered and cohesive polymeric structure can help to obtain films with good properties. Simple aqueous-based film formulation techniques and utilization of waste/byproducts can stimulate the adoption of affordable biobased films on a large-scale.

Zinc oxide nanoparticle-reinforced pectin/starch functionalized films: A sustainable solution for biodegradable packaging

Environmental pollution caused by non-biodegradable plastic pollutants adversely affects various ecosystems. This study proposes the development of novel functional and biodegradable films based on corn starch (CST) and pectin (PEC) containing zinc oxide nanoparticles (ZnONPs) from the casting method. The films exhibited processability, transparency, low water vapor permeation, and desirable mechanical properties for food packaging and coating applications. The ZnONPs acted as a plasticizer, enhancing the film elongation at the break, increasing the pec25-1 (PEC 25 wt% and ZnONPs 1 wt%) elongation from 79.85 to 162.32 %. The improved film elasticity supported by ZnONPs reduced the material stiffness. However, the films still demonstrated an average tensile strength (0.69 MPa) 17-fold higher than the tensile strength (0.04 MPa) of the non-biodegradable commercial film based on poly(vinyl chloride). Furthermore, the ZnONPs enhanced the UV-blocking capabilities of the films, leading to wettable materials with water contact angles lower than 90°. The films showed high biodegradation rates under natural disposal conditions. The results indicated that the pec25-1/ZnONPs film is a promising eco-friendly coating in food preservation due to its biodegradability, suitable mechanical properties, low water vapor permeability, and UV-blocking properties.

Biosurfactant-capped CuO nanoparticles coated cotton/polypropylene fabrics toward antimicrobial textile applications

The global COVID-19 pandemic has led to an increase in the importance of implementing effective measures to prevent the spread of microorganisms. Consequently, there is a growing demand for antimicrobial materials, specifically antimicrobial textiles and face masks, because of the surge in diseases caused by bacteria and viruses like SARS-CoV-2. Face masks that possess built-in antibacterial properties can rapidly deactivate microorganisms, enabling reuse and reducing the incidence of illnesses. Among the numerous types of inorganic nanomaterials, copper oxide nanoparticles (CuO NPs) have been identified as cost-effective and highly efficient antimicrobial agents for inactivating microbes. Furthermore, biosurfactants have recently been recognized for their potential antimicrobial effects, in addition to inorganic nanoparticles. Therefore, this research's primary focus is synthesizing biosurfactant-mediated CuO NPs, integrating them into natural and synthetic fabrics such as cotton and polypropylene and evaluating the resulting fabrics' antimicrobial activity. Using rhamnolipid (RL) as a biosurfactant and employing a hydrothermal method with a pH range of 9-11, RL-capped CuO NPs are synthesized (RL-CuO NPs). To assess their effectiveness against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) microorganisms, the RL-CuO NPs are subjected to antibacterial testing. The RL-capped CuO NPs exhibited antimicrobial activity at much lower concentrations than the individual RL, CuO. RL-CuO NPs have shown a minimum inhibitory concentration (MIC) of 1.2 mg ml-1and minimum bactericidal concentration (MBC) of 1.6 mg ml-1forE. coliand a MIC of 0.8 mg ml-1and a MBC of 1.2 mg ml-1forS. aureus, respectively. Furthermore, the developed RL-CuO NPs are incorporated into cotton and polypropylene fabrics using a screen-printing technique. Subsequently, the antimicrobial activity of the coated fabrics is evaluated, revealing that RL-CuO NPs coated fabrics exhibited remarkable antibacterial properties against both gram-positive and gram-negative bacteria.

Preparation and characterization of gelatin/chitosan nanocomposite reinforced by NiO nanoparticles as an active food packaging

Food packaging with antibacterial properties has attracted much attention recently. In this study, nickel oxide nanoparticles (NiONPs) were synthesized by co-precipitation and then gelatin/chitosan polymer films (GEL/CS) with different percentages of NiONPs, bio-nanocomposites, were prepared by casting. Morphology, crystal microstructure, molecular interactions and thermal stabilities of the NPs and the composite films were characterized by FESEM, XRD, FTIR and TGA, respectively. The bio-nanocomposite films exhibited excellent barrier, thermal and mechanical properties by addition of an optimized content of NPs. For example, the tensile strength (TS) of the GEL/CS film without NPs was 23.83 MPa and increased to 30.13 MPa by incorporation of 1% NPs. The antibacterial properties and toxicity of the films were investigated. These films show good antibacterial behavior against Gram-positive (Staphylococcus aureus) bacteria compared to Gram-negative (Escherichia coli) bacteria. Furthermore, the films were found to be non-toxic to fibroblast cells that came into contact with the films, with a survival rate of more than 88%. Therefore, these films can be applied for food packaging due to their excellent mechanical, barrier, and antibacterial properties.

Starch-based antibacterial food packaging with ZnO nanoparticle

Starch-based biofilms with embedded nanoparticles (NPs) are used to wrap food in biodegradable packaging system that has high antibacterial action against a variety of microorganisms. In this study, ZnO NPs were synthesised using both a green synthesis approach utilising Azadirachta indica (Neem) and a chemical synthesis approach using the sol-gel technique. The structural and morphological properties of all synthesized NPs were characterized through XRD, UV-VIS, UV-DRS, FTIR, and FESEM analysis. Further, these NPs were employed in the development of starch-based biodegradable films. A meticulous comparative analysis was performed to evaluate the functional properties of the nanocomposites, encompassing crucial parameters such as film thickness, moisture content, swelling index, opacity, solubility, water vapor permeability, and tensile strength. In comparison to films embedded with chemically synthesised NPs (F1), nanocomposite with green synthesised NPs (F2) showed 15.27% greater inhibition against Escherichia coli growth and 22.05% stronger inhibition against Staphylococcus aureus bacterial strains. Based on the biodegradability analysis, the nanocomposite film-F2 showed a 53.33% faster degradation rate compared to the film-F1. The developed films were utilized to assess the quality of both wrapped and unwrapped grapes, leading to the generalization of the research for the development of starch-based antibacterial and environmentally friendly food packaging material.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05834-9.

Polysaccharides and proteins based bionanocomposites as smart packaging materials: From fabrication to food packaging applications a review

Food industry is the biggest and rapidly growing industries all over the world. This sector consumes around 40 % of the total plastic produced worldwide as packaging material. The conventional packaging material is mainly petrochemical based. However, these petrochemical based materials impose serious concerns towards environment after its disposal as they are nondegradable. Thus, in search of an appropriate replacement for conventional plastics, biopolymers such as polysaccharides (starch, cellulose, chitosan, natural gums, etc.), proteins (gelatin, collagen, soy protein, etc.), and fatty acids find as an option but again limited by its inherent properties. Attention on the initiatives towards the development of more sustainable, useful, and biodegradable packaging materials, leading the way towards a new and revolutionary green era in the food sector. Eco-friendly packaging materials are now growing dramatically, at a pace of about 10-20 % annually. The recombination of biopolymers and nanomaterials through intercalation composite technology at the nanoscale demonstrated some mesmerizing characteristics pertaining to both biopolymer and nanomaterials such as rigidity, thermal stability, sensing and bioactive property inherent to nanomaterials as well as biopolymers properties such as flexibility, processability and biodegradability. The dramatic increase of scientific research in the last one decade in the area of bionanocomposites in food packaging had reflected its potential as a much-required and important alternative to conventional petroleum-based material. This review presents a comprehensive overview on the importance and recent advances in the field of bionanocomposite and its application in food packaging. Different methods for the fabrication of bionanocomposite are also discussed briefly. Finally, a clear perspective and future prospects of bionanocomposites in food packaging were presented.

Manipulation of crystallization nucleation and thermal degradation of PLA films by multi-morphologies CNC-ZnO nanoparticles

Currently, the quest for more renewable and biodegradable materials is a scientific priority to address the problems of petroleum-based plastics are difficult to degrade. In this work, cellulose nanocrystals (CNC) have been used as a template and four morphologies of CNC-ZnO nanocomposites were prepared via a hydrothermal method, and CNC-ZnO/polylactic acid (PLA) composite films were obtained by solution casting. We find that CNC-ZnO nanocomposites as heterogeneous nucleating agents improved the crystallinity and the film with flower-like CNC-ZnO was improved by 2.4 %. Ea required for thermal degradation of the PLA films decreased to 66-81 % of that of neat PLA, calculated by the Kissinger method, the Friedman method, and the Flynn-Wall-Ozawa (FWO) method. The R2 model was the solid degradation mechanism of the PLA films, analyzed through the Coats-Redfern method and the Criado method. The H-bond content of the composite films was significantly reduced after thermal aging at 150 °C. We found that three-dimensional CNC-ZnO (ZnO-3) made more prominent contributions to the crystallization, thermal degradation, and thermal aging of PLA films than other dimensional. The thermal properties can be regulated by the dimension, size, and apparent morphology of CNC-ZnO nanoparticles.

Evaluation of chitosan-Ag/TiO2 nanocomposite for the enhancement of shelf life of chili and banana fruits

Post-harvest losses of fruits and vegetables account for a large share of food waste in the world due to improper handling and packaging. By using the sol-gel method, Ag/TiO2 nanocomposite was prepared in this study from micro-sized commercial TiO2 powder and incorporated in a chitosan-cellulose matrix for the purpose of promising food packaging. The particle size and distribution of Ag nanoparticles (9.2437 nm size) confirmed their successful inclusion in the TiO2 surface. The morphology of the package assured the successful and uniform disbursement of Ag/TiO2 nanocomposite into the chitosan-cellulose matrix, which led to enhanced water resistance and photocatalytic activity. The developed package is proficient in hindering the growth of fecal coliform bacteria (Esche (Escherichia coli) by 9 mm in the agar plate. Moreover, the efficient application of chitosan-Ag/TiO2 nanocomposite in food coating and packaging was examined in extending shelf life, minimizing water loss, and preventing microbial infection during the storage of chili (up to 7 days at 37 °C) and banana, respectively. It can be concluded from the results that chitosan-Ag/TiO2 nanocomposite-based food coating and packaging have competent potential for enhancing the shelf life of moist foods.

Effect of Nano-Silica and Sorbitol on the Properties of Chitosan-Based Composite Films

Chitosan and its derivatives are widely used in food packaging, pharmaceutical, biotechnology, medical, textile, paper, agriculture, and environmental industries. However, the flexibility of chitosan films is extremely poor, which limits its relevant applications to a large extent. In this paper, chitosan/sorbitol/nano-silica (CS/sorbitol/SiO2) composite films were prepared by the casting film method using chitosan, sorbitol, Tween-80 and nano-SiO2 as raw materials. The structure of the films was characterized by infrared spectroscopy, electron scanning microscopy, and X-ray diffraction analysis. The effects of sorbitol and nano-silica dosage on the mechanical properties, thermal properties and water vapor barrier properties of the composite film were investigated. The results show that with the gradual increase in sorbitol (≤75 wt %), the elongation at the break of chitosan/sorbitol films significantly increased. When the addition of sorbitol was 75 wt %, the elongation at break of the chitosan/sorbitol composite film was 13 times higher than that of the chitosan film. Moreover, nano-SiO2 can further improve the mechanical properties and thermal stability of the chitosan/sorbitol composite films. When the amount of nano-silica was 4.5 wt %, the composite film became more flexible, with a maximum elongation of 90.8% (which is 14 times that of chitosan film), and its toughness increased to 10.52 MJm-3 (which is 6 times that of chitosan film). This study balances the tensile strength and elongation at break of the composite films by adding a plasticizer and nano-filler, providing a reference for the preparation of chitosan composites or their blending with other polymers, and has practical guiding significance for the industrial production of biomass plastics.

A State-of-the-Art Systemic Review on Selenium Nanoparticles: Mechanisms and Factors Influencing Biogenesis and Its Potential Applications

Selenium is a trace element required for the active function of numerous enzymes and various physiological processes. In recent years, selenium nanoparticles draw the attention of scientists and researchers because of its multifaceted uses. The process involved in chemically synthesized SeNPs has been found to be hazardous in nature, which has paved the way for safe and ecofriendly SeNPs to be developed in order to achieve sustainability. In comparison to chemical synthesis, SeNPs can be synthesized more safely and with greater flexibility utilizing bacteria, fungi, and plants. This review focused on the synthesis of SeNPs utilizing bacteria, fungi, and plants; the mechanisms involved in SeNP synthesis; and the effect of various abiotic factors on SeNP synthesis and morphological characteristics. This article discusses the synergies of SeNP synthesis via biological routes, which can help future researchers to synthesize SeNPs with more precision and employ them in desired fields.

A Review on Reinforcements and Additives in Starch-Based Composites for Food Packaging

The research of starch as a matrix material for manufacturing biodegradable films has been gaining popularity in recent years, indicating its potential and possible limitations. To compete with conventional petroleum-based plastics, an enhancement of their low resistance to water and limited mechanical properties is essential. This review aims to discuss the various types of nanofillers and additives that have been used in plasticized starch films including nanoclays (montmorillonite, halloysite, kaolinite, etc.), poly-saccharide nanofillers (cellulose, starch, chitin, and chitosan nanomaterials), metal oxides (titanium dioxide, zinc oxide, zirconium oxide, etc.), and essential oils (carvacrol, eugenol, cinnamic acid). These reinforcements are frequently used to enhance several physical characteristics including mechanical properties, thermal stability, moisture resistance, oxygen barrier capabilities, and biodegradation rate, providing antimicrobial and antioxidant properties. This paper will provide an overview of the development of starch-based nanocomposite films and coatings applied in food packaging systems through the application of reinforcements and additives.

Metal-Based Nanoparticles in Food Packaging and Coating Technologies: A Review

Food security has continued to be a topic of interest in our world due to the increasing demand for food. Many technologies have been adopted to enhance food supply and narrow the demand gap. Thus, the attempt to use nanotechnology to improve food security and increase supply has emerged due to the severe shortcomings of conventional technologies, which have made them insufficient to cater to the continuous demand for food products. Hence, nanoparticles have been identified to play a major role in areas involving food production, protection, and shelf-life extensions. Specifically, metal-based nanoparticles have been singled out to play an important role in manufacturing materials with outstanding properties, which can help increase the shelf-life of different food materials. The physicochemical and biological properties of metal-based nanoparticles, such as the large surface area and antimicrobial properties, have made them suitable and adequately useful, not just as a regular packaging material but as a functional material upon incorporation into biopolymer matrices. These, amongst many other reasons, have led to their wide synthesis and applications, even though their methods of preparation and risk evaluation remain a topic of concern. This review, therefore, briefly explores the available synthetic methods, physicochemical properties, roles, and biological properties of metal-based nanoparticles for food packaging. Furthermore, the associated limitations, alongside quality and safety considerations, of these materials were summarily explored. Although this area of research continues to garner attention, this review showed that metal-based nanoparticles possess great potential to be a leading material for food packaging if the problem of migration and toxicity can be effectively modulated.

Biosynthesis of selenium nanoparticles by lactic acid bacteria and areas of their possible applications

Lactic acid bacteria, being generally recognized as safe, are the preferred choice among other microbial producers of selenium nanoparticles. For successful production of SeNPs, it is necessary to take into account the physiological properties of the bacterium used as a biotransformer of inorganic forms of selenium in Se⁰. The antimicrobial and antioxidant activity of SeNPs allows to use them in the form of pure nanoparticles or biomass of lactic acid bacteria enriched with selenium in preparation of food, in agriculture, aquaculture, medicine, veterinary, and manufacturing of packing materials for food products. To attract attention to the promising new directions of lactic acid bacteria applications and to accelerate their implementation, the examples of the use of SeNPs synthesized by lactic acid bacteria in the mentioned above areas of human activity are described.

Development of Smart Films of a Chitosan Base and Robusta Coffee Peel Extract for Monitoring the Fermentation Process of Pickles

Smart film is widely used in the field of food packaging. The smart film was prepared by adding anthocyanin-rich Robusta coffee peel (RCP) extract into a chitosan (CS)-glycerol (GL) matrix by a solution-casting method. By changing the content of RCP (0, 10%, 15% and 20%) in the CS-GL film, the related performance indicators of CS-GL-RCP films were studied. The results showed that the CS-GL-RCP films had excellent mechanical properties, and CS-GL-RCP15 film maintained the tensile strength (TS) of 16.69 MPa and an elongation-at-break (EAB) of 18.68% with RCP extract. CS-GL-RCP films had the best UV-vis light barrier property at 200-350 nm and the UV transmittance was close to 0. The microstructure observation results showed that CS-GL-RCP films had a dense and uniform cross section, which proved that the RCP extract had good compatibility with the polymer. In addition, the CS-GL-RCP15 film was pH-sensitive and could exhibit different color changes with different pH solutions. So, the CS-GL-RCP15 film was used to detect the fermentation process of pickles at 20 ± 1 °C for 15 days. The pickles were stored in a round pickle container after the boiling water had cooled. The color of the CS-GL-RCP15 film changed significantly, which was consistent with the change of pickles from fresh to mature. The color of the smart film changed significantly with the maturity of pickles, and the difference of ΔE of film increased to 8.89 (15 Days), which can be seen by the naked eye. Therefore, CS-GL-RCP films prepared in this study provided a new strategy for the development of smart packaging materials.

Essential characteristics improvement of metallic nanoparticles loaded carbohydrate polymeric films - A review

Petroleum-based films have contributed immensely to various environmental issues. Developing green-based films from carbohydrate polymers is crucial for addressing the harms encountered. However, some limitations exist on their property, processibility, and applicability that prohibit their processing for further developments. This review discusses the potential carbohydrate polymers and their sources, film preparation methods, such as solvent-casting, tape-casting, extrusion, and thermo-mechanical compressions for green-based films using various biological polymers with their merits and demerits. Research outcomes revealed that the essential characteristics improvement achieved by incorporating different metallic nanoparticles has significantly reformed the properties of biofilms, including crystallization, mechanical stability, thermal stability, barrier function, and antimicrobial activity. The property-enhanced bio-based films made with nanoparticles are potentially interested in replacing fossil-based films in various areas, including food-packaging applications. The review paves a new way for the commercial use of numerous carbohydrate polymers to help maintain a sustainable green environment.

Metal Oxide Nanoparticles in Food Packaging and Their Influence on Human Health

It is a matter of common knowledge in the literature that engineered metal oxide nanoparticles have properties that are efficient for the design of innovative food/beverage packages. Although nanopackages have many benefits, there are circumstances when these materials are able to release nanoparticles into the food/beverage matrix. Once dispersed into food, engineered metal oxide nanoparticles travel through the gastrointestinal tract and subsequently enter human cells, where they display various behaviors influencing human health or wellbeing. This review article provides an insight into the antimicrobial mechanisms of metal oxide nanoparticles as essential for their benefits in food/beverage packaging and provides a discussion on the oral route of these nanoparticles from nanopackages to the human body. This contribution also highlights the potential toxicity of metal oxide nanoparticles for human health. The fact that only a small number of studies address the issue of food packaging based on engineered metal oxide nanoparticles should be particularly noted.

Antimicrobial Nano-Zinc Oxide Biocomposites for Wound Healing Applications: A Review

Chronic wounds are a major concern for global health, affecting millions of individuals worldwide. As their occurrence is correlated with age and age-related comorbidities, their incidence in the population is set to increase in the forthcoming years. This burden is further worsened by the rise of antimicrobial resistance (AMR), which causes wound infections that are increasingly hard to treat with current antibiotics. Antimicrobial bionanocomposites are an emerging class of materials that combine the biocompatibility and tissue-mimicking properties of biomacromolecules with the antimicrobial activity of metal or metal oxide nanoparticles. Among these nanostructured agents, zinc oxide (ZnO) is one of the most promising for its microbicidal effects and its anti-inflammatory properties, and as a source of essential zinc ions. This review analyses the most recent developments in the field of nano-ZnO–bionanocomposite (nZnO-BNC) materials—mainly in the form of films, but also hydrogel or electrospun bandages—from the different preparation techniques to their properties and antibacterial and wound-healing performances. The effect of nanostructured ZnO on the mechanical, water and gas barrier, swelling, optical, thermal, water affinity, and drug-release properties are examined and linked to the preparation methods. Antimicrobial assays over a wide range of bacterial strains are extensively surveyed, and wound-healing studies are finally considered to provide a comprehensive assessment framework. While early results are promising, a systematic and standardised testing procedure for the comparison of antibacterial properties is still lacking, partly because of a not-yet fully understood antimicrobial mechanism. This work, therefore, allowed, on one hand, the determination of the best strategies for the design, engineering, and application of n-ZnO-BNC, and, on the other hand, the identification of the current challenges and opportunities for future research.

Design and characterization of an antibacterial film composited by hydroxyethyl cellulose (HEC), carboxymethyl chitosan (CMCS), and nano ZnO for food packaging

For food packaging, a novel composite film was prepared by solution casting method using hydroxyethyl cellulose (HEC), carboxymethyl chitosan (CMCS), and zinc oxide nanoparticles as raw materials. The composite film successfully compounded the nanoparticles, as deduced by spectroscopy, crystallography and morphology observation. The addition of CMCS and ZnO enhanced the solvent resistance (the water solubility of the composite film was reduced by 94.3 %) and UV shielding ability (the UV shielding capacity of the composite film was increased by 45.73 %) of the composite film, thus improving the application prospects of the composite film in water-rich foods. In addition, the synergistic effect of CMCS and ZnO helped the composite film to efficiently inhibit the pathogenic bacteria Listeria monocytogenes and Pseudomonas aeruginosa (rate of inhibition>99.99 %) in food. The addition of CMCS and ZnO also significantly improved the elasticity (improve 494.34 %) and maximum load capacity (improve 142.24 %) of the composite film.

Encapsulation and antibacterial studies of goji berry and garlic extract in the biodegradable chitosan

As known, the chitosan is a biodegradable biopolymer with antibacterial properties, therefore it is used in the fields of pharmacy, medical, wastewater treatment, biotechnology, cosmetics, textiles, and agriculture. Apart from these, the chitosan has an important place in the food industry with its widespread use. In this research article, the chitosan were encapsulated with the taurine and garlic extracts by the spray dryer. The CSA and CSB compounds synthesized as final products were analyzed by Fourier transformed infrared spectroscopy (FTIR) and High Performance Liquid Chromatography (HPLC). The effect of the encapsulation process on the molecular weight of the polymer structure was investigated using the cryoscopy method. The compound CSA represents 1/2 encapsulation of chitosan with taurine and increased garlic extracts, respectively, while CSB represents 1/1 encapsulation of chitosan with increased taurine and fixed garlic extracts. The % antioxidant activity of the final products was determined by DDPH method. The inhibition zone and surface activity proporties of the CSA and CSB were carried out against Listeria monocytogenes, Staphylococcus aureus, E. coli, and Salmonella bacteria. The results obtained as a result of the analyzes were evaluated, and optimum values were determined for use in food packaging.

Copper-based nanoparticles for biopolymer-based functional films in food packaging applications

This review summarizes the latest developments in the design, fabrication, and application of various Cu-based nanofillers to prepare biopolymer-based functional packaging films, focusing on the effects of inorganic nanoparticles on the optical, mechanical, gas barrier properties, moisture sensitivity, and functional properties of the films. In addition, the potential application of Cu-based nanoparticle-added biopolymer films for fresh food preservation and the effect of nanoparticle migration on food safety were discussed. The incorporation of Cu-based nanoparticles improved the film properties with enhanced functional performance. Cu-based nanoparticles such as copper oxide, copper sulfide, copper ions, and copper alloys affect biopolymer-based films differently. The properties of composite films containing Cu-based nanoparticles depend on the concentration of the filler, the state of dispersion, and the interaction of the nanoparticles with the biopolymer matrix in the film. The composite film filled with Cu-based nanoparticles effectively extended the shelf life by maintaining the quality of various fresh foods and securing safety. However, studies on the migration characteristics and safety of copper-based nanoparticle food packaging films are currently being conducted on plastic-based films such as polyethylene, and research on bio-based films is limited.

Preparation, characterization, and antibacterial effect of bio-based modified starch films

There are several problems with common starch films, including strong water absorption and poor mechanical properties. To create a better starch film, octenyl succinate cassava starch ester (OSCS) was first blended with chitosan and nano ZnO to prepare an OSCS/CS/ZnO film. Then, the film was supplemented with different concentrations of ε-PL as a bacteriostatic agent to prepare a film that would resist bacterial invasion. The mechanical properties, barrier properties, optical properties, and color of the modified starch antibacterial films were investigated, and finally the antibacterial properties and cytotoxicity were tested. The results demonstrated that the modified starch antibacterial film had good mechanical properties, improved surface hydrophobicity, and had a UV-blocking effect. The modified starch antibacterial film with ε-PL of 8% had stable and long-lasting antibacterial properties, stable release, and good cytocompatibility. An active packaging material was successfully prepared using ε-PL and had a strong preservative effect on food.

Proporties and Synthesis of Biosilver Nanofilms for Antimicrobial Food Packaging

In this original research, biodegradable corn starch (CS) and wheat gluten (wg)-based silver nanofilms were synthesized and analyzed by using goji berry extract taurine (ta), garlic extract (GC), whey powder (wh), and montmorillonite clay nanoparticles. Antibacterial-corn-starch-based nano films were analyzed by using the methods of high-performance liquid chromatography (HPLC), Fourier Transform infrared spectroscopy (FTIR-ATR), X-ray diffraction (XRD), dynamic and mechanical (DMA) analysis, and scanning electron microscopy (SEM). In addition, the antibacterial resistances of the corn starch nano films against the bacteria Salmonella and Staphylococcus aureus (S. aureus) and Listeria monocytogenes were examined and the migration assays were carried out. The migration analysis results of CS₁, CS₂, and CS₃ nanocomposite films were found as 0.305, 0.297, and 0.297 mg/dm², respectively. The inhibition zone of CS₁, CS₂, and CS₃ nanocomposite films were found as 1547, 386, and 1884 mm² against Salmonella bacteria. The results show that silver nanofilms are suitable as packaging films for the production of packaging in milk and dairy products, liquid foods, and acidic foods.

Recent insights into metallic nanoparticles in shelf-life extension of agrifoods: Properties, green synthesis, and major applications

Nanotechnology emerged as a revolutionary technology in various fields of applied sciences, such as biomedical engineering and food technology. The pivotal roles of nanocompounds have been explored in various fields, such as food protection, preservation, and enhancement of shelf life. In this sequence, metallic nanoparticles (MNPs) are proven to be useful in developing products with antimicrobial activity and subsequently improve the shelf life of agrifoods. The major application of MNPs has been observed in the packaging industry due to the combining ability of biopolymers with MNPs. In recent years, various metal nanoparticles have been explored to formulate various active food packaging materials. However, the method of production and the need for risk evaluation are still a topic of discussion among researchers around the world. In general, MNPs are synthesized by various chemical and physical means, which may pose variable health risks. To overcome such issues, the green synthesis of MNPs using microbial and plant extracts has been proposed by various researchers. In this review, we aimed at exploring the green synthesis of MNPs, their properties and characterization, various ways of utilizing MNPs to extend their shelf life, and, most importantly, the risk associated with these along with their quality and safety considerations.

A review: Silver–zinc oxide nanoparticles – organoclay-reinforced chitosan bionanocomposites for food packaging

Research on bionanocomposites has been developed, while its application as food packaging is still being explored. They are usually made from natural polymers such as cellulose acetate, chitosan (CS), and polyvinyl alcohol. Bionanocomposite materials can replace traditional non-biodegradable plastic packaging materials, enabling them to use new, high-performance, lightweight, and environmentally friendly composite materials. However, this natural polymer has a weakness in mechanical properties. Therefore, a composite system is needed that will improve the properties of the biodegradable food packaging. The aim of this mini-review is to demonstrate recent progress in the synthesis, modification, characterization, and application of bionanocomposites reported by previous researchers. The focus is on the preparation and characterization of CS-based bionanocomposites. The mechanical properties of CS-based food packaging can be improved by adding reinforcement from inorganic materials such as organoclay. Meanwhile, the anti-bacterial properties of CS-based food packaging can be improved by adding nanoparticles such as Ag and ZnO.

Biodegradable active packaging: Components, preparation, and applications in the preservation of postharvest perishable fruits and vegetables

The consumption of fresh fruits and vegetables is restricted by the susceptibility of fresh produce to deterioration caused by postharvest physiological and metabolic activities. Developing efficient preservation strategies is thus among the most important scientific issues to be urgently addressed in the field of food science. The incorporation of active agents into a polymer matrix to prepare biodegradable active packaging is being increasingly explored to mitigate the postharvest spoilage of fruits and vegetables during storage. This paper reviews the composition of biodegradable polymers and the methods used to prepare biodegradable active packaging. In addition, the interactions between bioactive ingredients and biodegradable polymers that can lead to plasticizing or cross-linking effects are summarized. Furthermore, the applications of biodegradable active (i.e., antibacterial, antioxidant, ethylene removing, barrier, and modified atmosphere) packaging in the preservation of fruits and vegetables are illustrated. These films may increase sensory acceptability, improve quality, and prolong the shelf life of postharvest products. Finally, the challenges and trends of biodegradable active packaging in the preservation of fruits and vegetables are discussed. This review aims to provide new ideas and insights for developing novel biodegradable active packaging materials and their practical application in the preservation of postharvest fruits and vegetables.

Improving carboxymethyl cellulose edible coating using ZnO nanoparticles from irradiated Alternaria tenuissima

In this paper, gamma-irradiation was successfully used to intensify the yield of Zinc oxide nanoparticles (ZnONPs) produced by the fungus Alternariatenuissima as a sustainable and green process. The obtained data showed that 500 Gy of gamma-irradiation increased ZnONPs’ yield to approximately four-fold. The synthesized ZnONPs were then exploited to develop active Carboxymethyl Cellulose films by casting method at two different concentration of ZnONPs 0.5% and 1.0%. The physicochemical, mechanical, antioxidant, and antimicrobial properties of the prepared films were evaluated. The incorporation of ZnONPs in the Carboxymethyl Cellulose films had significantly decreased solubility (from 78.31% to 66.04% and 59.72%), water vapor permeability (from 0.475 g m⁻² to 0.093 g m⁻² and 0.026 g m⁻²), and oxygen transfer rate (from 24.7 × 10^–2 to 2.3 × 10^–2 and 1.8 × 10^–2) of the respective prepared films. Meanwhile, tensile strength (from 183.2 MPa to 203.34 MPa and 235.94 MPa), elongation (from 13.0% to 62.5% and 83.7%), and Yang's modulus (from 325.344 to 1410.0 and 1814.96 MPa) of these films were increased. Moreover, the antioxidant and antimicrobial activities against several human and plant pathogens the prepared of Carboxymethyl Cellulose-ZnONPs films were significantly increased. In conclusion, the prepared Carboxymethyl Cellulose-ZnONPs films showed enhanced activities in comparison with Carboxymethyl Cellulose film without NPs. With these advantages, the fabricated Carboxymethyl Cellulose-ZnONPs films in this study could be effectively utilized as protective edible coating films of food products.

Green Approaches, Potentials, and Applications of Zinc Oxide Nanoparticles in Surface Coatings and Films

Interest in the use of zinc oxide nanoparticles (ZnO NPs) in surface coatings and films has increased as its incorporation can significantly improve the mechanical and antimicrobial properties of coatings and film solutions. In an effort to produce green or eco-friendly products, the potential use of ZnO NPs biosynthesized from natural resources to replace conventional petroleum-derived polymers has been investigated. This review provides an insight into the growing trend of incorporating ZnO NPs into synthetic or semi-synthetic or bio-based polymeric materials via different synthesis methods as well as its characteristics and potential applications in surface coatings and films. The antimicrobial potential of ZnO NPs to inhibit the growth of various types of microorganisms as well as its use in surface coatings or films to impart antimicrobial activities that prevent the spread of microorganisms, especially the COVID-19 virus, was also discussed.

Synthesis of CuO nanoparticles stabilized with gelatin for potential use in food packaging applications

In the present study, a method for the synthesis of gelatin-stabilized copper oxide nanoparticles was developed. Synthesis was carried out by direct chemical precipitation. Copper sulfate, chloride, and acetate were used as precursors for the copper oxide synthesis. Gelatin was used as a stabilizer. It was found that the formation of monophase copper oxide II only occurred when copper acetate was used as a precursor. Our results showed that particles of the smallest diameter are formed in an aqueous medium (18 ± 6 nm), and those of th largest diameter—in an isobutanol medium (370 ± 131 nm). According to the photon correlation spectroscopy data, copper oxide nanoparticles synthesized in an aqueous medium were highly stable and had a monomodal size distribution with an average hydrodynamic radius of 61 nm. The study of the pH effect on the colloidal stability of copper oxide nanoparticles showed that the sample was stable in the pH range of 6.8 to 11.98. A possible mechanism for the pH influence on the stability of copper oxide nanoparticles is described. The effect of the ionic strength of the solution on the stability of the CuO nanoparticles sol was also studied, and the results showed that Ca²⁺ ions had the greatest effect on the sample stability. IR spectroscopy showed that the interaction of CuO nanoparticles with gelatin occurred through the hydroxyl group. It was found that CuO nanoparticles stabilized with gelatin have a fungicidal activity at concentration equivalent 2.5 · 10⁻³ mol/L and as a material for food nanopackaging can provide an increase in the shelf life of products on the example of strawberries and tomatoes. We investigated the possibility of using methylcellulose films modified with CuO nanoparticles for packaging and storage of hard cheese “Holland”. The distribution of CuO nanoparticles in the methylcellulose film was uniform. We found that methylcellulose films modified with CuO nanoparticles inhibited the growth and development of QMAFAM, coliforms, yeast and mold in experimental cheese sa mples. Our research has shown that during the cheese storage in thermostat at 35 ± 1 °C for 7 days, CuO nanoparticles migrated to the product from the film. Nevertheless, it is worth noting that the maximum change in the concentration of copper in the experimental samples was only 0.12 µg/mg, which is not a toxic concentration. In general, the small value of migration of CuO nanoparticles confirms the high stability of the developed preparation. Our results indicated that the CuO nanoparticles stabilized with gelatin have a high potential for use in food packaging – both as an independent nanofilm and as part of other packaging materials.

Recent advances in biobased and biodegradable polymer nanocomposites, nanoparticles, and natural antioxidants for antibacterial and antioxidant food packaging applications

Inorganic nanoparticles (NPs) and natural antioxidant compounds are an emerging trend in the food industry. Incorporating these substances in biobased and biodegradable matrices as polysaccharides (e.g., starch, cellulose, and chitosan) and proteins has highlighted the potential in active food packaging applications due to more significant antimicrobial, antioxidant, UV blocking, oxygen scavenging, water vapor permeability effects, and low environmental impact. In recent years, the migration of metal NPs and metal oxides in food contact packaging and their toxicological potential have raised concerns about the safety of the nanomaterials. In this review, we provide a comprehensive overview of the main biobased and biodegradable polymer nanocomposites, inorganic NPs, natural antioxidants, and their potential use in active food packaging. The intrinsic properties of NPs and natural antioxidant actives in packaging materials are evaluated to extend shelf-life, safety, and food quality. Toxicological and safety aspects of inorganic NPs are highlighted to understand the current controversy on applying some nanomaterials in food packaging. The synergism of inorganic NPs and plant-derived natural antioxidant actives (e.g., vitamins, polyphenols, and carotenoids) and essential oils (EOs) potentiated the antibacterial and antioxidant properties of biodegradable nanocomposite films. Biodegradable packaging films based on green NPs-this is biosynthesized from plant extracts-showed suitable mechanical and barrier properties and had a lower environmental impact and offered efficient food protection. Furthermore, AgNPs and TiO₂ NPs released metal ions from packaging into contents insufficiently to cause harm to human cells, which could be helpful to understanding critical gaps and provide progress in the packaging field.

The antioxidant and antibacterial properties of chitosan encapsulated with the bee pollen and the apple cider vinegar

In this study, the chitosan, a polysaccharide, was encapsulated with the bee pollen and the apple cider vinegar. The freeze-drying method was used in the encapsulation process. The freeze cooling temperature was determined as -80 °C. The obtained encapsulated chitosan compounds were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and their molecular weights were determined by the cryoscopy method. The total amount of the phenol compounds and % the antioxidant activity of the synthesized compounds were measured by UV spectrophotometer and, the loading capacity of the polyphenol compounds in encapsulation was determined. The success of encapsulation was calculated based on the % encapsulation efficiency (%EE) calculation. The antibacterial and the surface activity properties of the obtained CSx and CSy compounds were analyzed against Listeria monocytogenes, Staphylococcus aureus, E. coli and Salmonella bacteria using the well diffusion method and the Zeiss microscope.

Antioxidant and cell-friendly Fe2TiO5 nanoparticles for food packaging application

An emerging technology of active packaging enables prolongation of food shelf life by limiting the oxygen transfer and the reactivity of free radicals, which both destruct food freshness. In this work, Fe₂TiO₅ nanoparticles were synthesized using a modified sol-gel method and evaluated as an enforcement of alginate food packaging film. Pure phase Fe₂TiO₅ nanoparticles had an average particle size of 44 nm and rhombohedral morphology. Fe₂TiO₅ nanoparticles induce no cell damage of human Caco-2 epithelial cells and show no inhibitory effect towards growth of a panel of bacterial strains, suggesting good biocompatibility. Films obtained by incorporation of Fe₂TiO₅ nanoparticles into alginate using the solvent casting method show no migration of iron or titanium ions from films to food simulants again suggesting their safety as a packaging material. Fe₂TiO₅ nanoparticles also showed strong antioxidant efficiency as determined using the DPPḢ assay, and confirmed further in a preservation test on fresh fruit.

Metallic Nanoparticle Integrated Ternary Polymer Blend of PVA/Starch/Glycerol: A Promising Antimicrobial Food Packaging Material

Advances in food processing and food packaging play a major role in keeping food safe, increasing the shelf life, and maintaining the food supply chain. Good packaging materials that enable the safe travel of food are often non-degradable and tend to persist in the environment, thereby posing a hazard. One alternative is to synthesize biodegradable polymers with an antimicrobial property while maintaining their mechanical and thermal properties. In the present study, biodegradable composites of PVA–starch–glycerol (PSG) incorporated with CuO and ZnO nanoparticles (NPs) were prepared as PSG, PSG–Cu, PSG–Zn, and PSG–CuZn films. Scanning electron microscopy, energy dispersive x-ray analysis, and thermogravimetric analysis were performed to study and characterize these films. The water barrier properties of the films improved significantly as the hydrophobicity of the PSG–CuZn film increased by 32.9% while the water absorptivity and solubility decreased by 51.49% and 60% compared to the PSG film. The Young’s modulus of the films incorporated with CuO and ZnO nanoparticles was lower than that reported for PVA, suggesting that the film possessed higher flexibility. The thermogravimetric analysis demonstrated high thermal stability for films. Biosynthesized CuO and ZnO nanoparticles exhibited antifungal activity against vegetable and fruit spoilage fungi, and hence the fabricated polymers incorporated with nanoparticles were anticipated to demonstrate an antifungal activity. The nanoparticle incorporated films exhibited fungicidal and bactericidal activity, suggesting their role in extending the shelf life of packaged food. The result of ICP-OES studies demonstrated the steady release of ions from the polymer films, however, EDX analysis demonstrated no leaching of CuO and ZnO nanoparticles from the films, thus ruling out the possibility of nanoparticles entering the packaged food. The strawberries wrapped with the fabricated films incorporated with nanoparticles demonstrated improved shelf life and retained the nutritional quality of the fruit. Among the four films, PSG–CuZn was the most promising for food wrapping since it exhibited better water-resistance, antimicrobial, thermal, and mechanical properties.

A Comprehensive Review of the Development of Carbohydrate Macromolecules and Copper Oxide Nanocomposite Films in Food Nanopackaging

Background. Food nanopackaging helps maintain food quality against physical, chemical, and storage instability factors. Copper oxide nanoparticles (CuONPs) can improve biopolymers’ mechanical features and barrier properties. This will lead to antimicrobial and antioxidant activities in food packaging to extend the shelf life. Scope and Approach. Edible coatings based on carbohydrate biopolymers have improved the quality of packaging. Several studies have addressed the role of carbohydrate biopolymers and incorporated nanoparticles to enhance food packets’ quality as active nanopackaging. Combined with nanoparticles, these biopolymers create film coatings with an excellent barrier property against transmissions of gases such as O2 and CO2. Key Findings and Conclusions. This review describes the CuO-biopolymer composites, including chitosan, agar, cellulose, carboxymethylcellulose, cellulose nanowhiskers, carrageenan, alginate, starch, and polylactic acid, as food packaging films. Here, we reviewed different fabrication techniques of CuO biocomposites and the impact of CuONPs on the physical, mechanical, barrier, thermal stability, antioxidant, and antimicrobial properties of carbohydrate-based films.

Antimicrobial starch/poly(butylene adipate-co-terephthalate) nanocomposite films loaded with a combination of silver and zinc oxide nanoparticles for food packaging

Antimicrobial starch/PBAT films with the combination of silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnONPs) were prepared by extrusion blowing. SEM demonstrated the relatively homogeneous distribution of nanoparticles on the fracture surfaces of the nanocomposite films. The incorporation of nanoparticles improved mechanical and barrier properties of the film. The UV-vis spectroscopy revealed that the SP-ZnO(1) film had the highest UV-absorbance. The inhibition effects of the nanocomposite films against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria were observed. The antimicrobial efficiency of SP-Ag(0.8)-ZnO(0.2) and SP-Ag(0.6)-ZnO(0.4) films reached more than 95% within 3 h of contact. The combination of AgNPs and ZnONPs into starch/PBAT blends showed synergistic effects on improving material properties and antimicrobial efficiency of the films. Furthermore, preliminary packaging studies on peaches and nectarines revealed that the antimicrobial films inhibited spoilage of fresh produce and extended their shelf life compared with commercial LDPE packaging films.

Metallic Nanoparticles in the Food Sector: A Mini-Review

Nanomaterials, and in particular metallic nanoparticles (MNPs), have significantly contributed to the production of healthier, safer, and higher-quality foods and food packaging with special properties, such as greater mechanical strength, improved gas barrier capacity, increased water repellency and ability to inhibit microbial contamination, ensuring higher quality and longer product shelf life. MNPs can also be incorporated into chemical and biological sensors, enabling the design of fast and sensitive monitoring devices to assess food quality, from freshness to detection of allergens, food-borne pathogens or toxins. This review summarizes recent developments in the use of MNPs in the field of food science and technology. Additionally, a brief overview of MNP synthesis and characterization techniques is provided, as well as of the toxicity, biosafety and regulatory issues of MNPs in the agricultural, feed and food sectors.