Nanocomposite Materials for Food Packaging Applications: Characterization and Safety Evaluation

Advancement in Fabrication and Characterization Techniques of Nanocomposites

Advancements in the field of materials research have unveiled numerous unparalleled features, such as mechanical properties, clinical advances, interfacial strengthening, and porosities, providing a wide range of applications. The employment of any material begins with fabrication and characterization, demanding expertise for the effective execution of the investigation. This review encompasses the details of the working principles of some significant and frequently used fabrication and characterization techniques for various material categories, including pellets and coatings. The discussion begins with techniques for fabricating materials for various applications. A brief overview of coating synthesis methods can provide intriguing information for researchers in the field of coating fabrication. The report highlights the portrayal of morphological and physiochemical analysis techniques, followed by the estimation of the elastic modulus using nanoindentation and dynamic modulus mapping testing for the materials. Additionally, the review covers theoretical models for observing the elastic moduli of the materials. The review depicts tribological investigations of the materials, aiming to provide insight into fretting wear, pin-on-disc, and microscratch testing. The fundamentals of electrochemical characterization are presented, including the appraisal of linear polarization and potentiodynamic polarization as well as electrochemical impedance spectroscopy. Furthermore, the magnetic behavior was examined by using a vibrating sample magnetometer (VSM), and the estimation of magnetic domains in the materials was conducted through magnetic force microscopy. Thus, the report suggests that readers, especially beginners, can gain a comprehensive understanding of the extensive prospects associated with the fundamental principles of material synthesis and characterization.

Effect of Calcium Oxide on Stress Crack Resistance and Light Transmittance in PET Containers for Packaging Carbonated Beverages

For polyethylene terephthalate (PET) bottles, a material used for food packaging, light transmission and mechanical performance, particularly environmental stress cracking (ESC), are essential characteristics. For this purpose, following extrusion of PET/CaO granules, preforms were manufactured using the injection technique, and bottles were produced by a stretch-blow-molding process. With incorporation of calcium oxide (CaO), light transmittance increased by around 25%, and ESC went from 0.3 to 11 min. In addition, whereas acetaldehyde (AA) and carboxylic acid (COOH) decomposition values rose with increasing CaO content, diethylene glycol and isophthalic acid values did not significantly change. Moreover, the maximum crystallization temperature and crystallinity both exhibited an upward trend with the CaO content.

A Review of Chitosan and Chitosan Nanofiber: Preparation, Characterization, and Its Potential Applications

Chitosan is produced by deacetylating the abundant natural chitin polymer. It has been employed in a variety of applications due to its unique solubility as well as its chemical and biological properties. In addition to being biodegradable and biocompatible, it also possesses a lot of reactive amino side groups that allow for chemical modification and the creation of a wide range of useful derivatives. The physical and chemical characteristics of chitosan, as well as how it is used in the food, environmental, and medical industries, have all been covered in a number of academic publications. Chitosan offers a wide range of possibilities in environmentally friendly textile processes because of its superior absorption and biological characteristics. Chitosan has the ability to give textile fibers and fabrics antibacterial, antiviral, anti-odor, and other biological functions. One of the most well-known and frequently used methods to create nanofibers is electrospinning. This technique is adaptable and effective for creating continuous nanofibers. In the field of biomaterials, new materials include nanofibers made of chitosan. Numerous medications, including antibiotics, chemotherapeutic agents, proteins, and analgesics for inflammatory pain, have been successfully loaded onto electro-spun nanofibers, according to recent investigations. Chitosan nanofibers have several exceptional qualities that make them ideal for use in important pharmaceutical applications, such as tissue engineering, drug delivery systems, wound dressing, and enzyme immobilization. The preparation of chitosan nanofibers, followed by a discussion of the biocompatibility and degradation of chitosan nanofibers, followed by a description of how to load the drug into the nanofibers, are the first issues highlighted by this review of chitosan nanofibers in drug delivery applications. The main uses of chitosan nanofibers in drug delivery systems will be discussed last.

Biomolecules from Macroalgae-Nutritional Profile and Bioactives for Novel Food Product Development

Seaweed is in the spotlight as a promising source of nutrition for humans as the search for sustainable food production systems continues. Seaweed has a well-documented rich nutritional profile containing compounds such as polyphenols, carotenoids and polysaccharides as well as proteins, fatty acids and minerals. Seaweed processing for the extraction of functional ingredients such as alginate, agar, and carrageenan is well-established. Novel pretreatments such as ultrasound assisted extraction or high-pressure processing can be incorporated to more efficiently extract these targeted ingredients. The scope of products that can be created using seaweed are wide ranging: from bread and noodles to yoghurt and milk and even as an ingredient to enhance the nutritional profile and stability of meat products. There are opportunities for food producers in this area to develop novel food products using seaweed. This review paper discusses the unique properties of seaweed as a food, the processes involved in seaweed aquaculture, and the products that can be developed from this marine biomass. Challenges facing the industry such as consumer hesitation around seaweed products, the safety of seaweed, and processing hurdles will also be discussed.

The Green Era of Food Packaging: General Considerations and New Trends

Recently, academic research and industries have gained awareness about the economic, environmental, and social impacts of conventional plastic packaging and its disposal. This consciousness has oriented efforts towards more sustainable materials such as biopolymers, paving the way for the “green era” of food packaging. This review provides a schematic overview about polymers and blends of them, which are emerging as promising alternatives to conventional plastics. Focus was dedicated to biopolymers from renewable sources and their applications to produce sustainable, active packaging with antimicrobial and antioxidant properties. In particular, the incorporation of plant extracts, food-waste derivatives, and nano-sized materials to produce bio-based active packaging with enhanced technical performances was investigated. According to recent studies, bio-based active packaging enriched with natural-based compounds has the potential to replace petroleum-derived materials. Based on molecular composition, the natural compounds can diversely interact with the native structure of the packaging materials, modulating their barriers, optical and mechanical performances, and conferring them antioxidant and antimicrobial properties. Overall, the recent academic findings could lead to a breakthrough in the field of food packaging, opening the gates to a new generation of packaging solutions which will be sustainable, customised, and green.

Applications and Prospects of Nanotechnology in Food and Cosmetics Preservation

Cosmetic and food products containing water are prone to contamination during the production, storage, and transit process, leading to product spoilage and degraded organoleptic characteristics. The efficient preservation of food and cosmetics is one of the most important issues the industry is facing today. The use of nanotechnology in food and cosmetics for preservation purposes offers the possibility to boost the activity of antimicrobial agents and/or promote their safer distribution into the end product upon incorporation into packaging or film constructions. In this review, current preservation strategies are discussed and the most recent studies in nanostructures used for preservation purposes are categorized and analyzed in a way that hopefully provides the most promising strategies for both the improvement of product safety and shelf-life extension. Packaging materials are also included since the container plays a major role in the preservation of such products. It is conclusively revealed that most of the applications refer to the nanocomposites as part of the packaging, mainly due to the various possibilities that nanoscience offers to this field. Apart from that, the route of exposure being either skin or the gastrointestinal system involves safety concerns, and since migration of nanoparticles (NPs) from their container can be measured, concerns can be minimized. Conclusion: Nanomaterial science has already made a significant contribution to food and cosmetics preservation, and rapid developments in the last years reinforce the belief that in the future much of the preservation strategies to be pursued by the two industries will be based on NPs and their nanocomposites.

Global Research Trends on the Use of Nanotechnology to Boost Meat Production: A Scientometric Analysis

Meat production plays a vital socioeconomic role for sustainable development and for promoting food security in most countries. However, not much is known about research agendas done globally and the advancement of knowledge-generating networks in this area of study. The present study aims to reveal and analyze scientific research outputs on meat production linked with recent nanotechnology research work done till date. A compilation of research advancement and development within the sphere was realized through a scientometric study to comprehend the trend of research outputs, scientific impacts, authors' involvement, collaboration networks, and the advancement of knowledge gaps for future research endeavors on the current subject matter. Scholarly published articles were retrieved from the web of science (WOS) and Scopus databases from 1985 to 2020 and they were merged together using bibliometric package in R studio. All duplicated articles (438) from both data bases were excluded. A combination of terms (nano* AND (livestock* OR meat* OR beef* OR mutton* OR pork* OR chevon* OR chicken* OR turkey*)), and conversely analyzed for scientometric indices. A collection of 656 peer-reviewed, research articles were retrieved for the study period and authored by 2,133 researchers with a collaboration index of 3.31. The research outputs were highest in the year 2020 with total research outputs of 140 articles. The topmost three authors' keywords commonly used by authors were nanoparticles, meat, and chitosan with a respective frequency of 75, 62, and 57. China, Iran, and India ranked top in terms of meat production research outputs linked to nanotechnology and total citation with respective article productivity (total citations) of 160 (3,193), 111 (1,765), and 37 (552). Our findings revealed an increasing trend in research (with an annual growth rate of 25.18%) tending toward advancing meat production with the use of nanotechnology. Likewise, there is an increasing pointer to the fact that research work on nanotechnology and meat production has the prospect to influence positively, decision-making on research direction, and collaborations, hereby increasing the production of meat and its products in the future.

Electrospinning of Chitosan for Antibacterial Applications—Current Trends

Chitosan is a natural biopolymer that can be suitable for a wide range of applications due to its biocompatibility, rigid structure, and biodegradability. Moreover, it has been proven to have an antibacterial effect against several bacteria strains by incorporating the advantages of the electrospinning technique, with which tailored nanofibrous scaffolds can be produced. A literature search is conducted in this review regarding the antibacterial effectiveness of chitosan-based nanofibers in the filtration, biomedicine, and food protection industries. The results are promising in terms of research into sustainable materials. This review focuses on the electrospinning of chitosan for antibacterial applications and shows current trends in this field. In addition, various aspects such as the parameters affecting the antibacterial properties of chitosan are presented, and the application areas of electrospun chitosan nanofibers in the fields of air and water filtration, food storage, wound treatment, and tissue engineering are discussed in more detail.

Novel Bio-Based Materials and Applications in Antimicrobial Food Packaging: Recent Advances and Future Trends

Food microbial contamination not only poses the problems of food insecurity and economic loss, but also contributes to food waste, which is another global environmental problem. Therefore, effective packaging is a compelling obstacle for shielding food items from outside contaminants and maintaining its quality. Traditionally, food is packaged with plastic that is rarely recyclable, negatively impacting the environment. Bio-based materials have attracted widespread attention for food packaging applications since they are biodegradable, renewable, and have a low carbon footprint. They provide a great opportunity to reduce the extensive use of fossil fuels and develop food packaging materials with good properties, addressing environmental problems and contributing significantly to sustainable development. Presently, the developments in food chemistry, technology, and biotechnology have allowed us to fine-tune new methodologies useful for addressing major safety and environmental concerns regarding packaging materials. This review presents a comprehensive overview of the development and potential for application of new bio-based materials from different sources in antimicrobial food packaging, including carbohydrate (polysaccharide)-based materials, protein-based materials, lipid-based materials, antibacterial agents, and bio-based composites, which can solve the issues of both environmental impact and prevent foodborne pathogens and spoilage microorganisms. In addition, future trends are discussed, as well as the antimicrobial compounds incorporated in packaging materials such as nanoparticles (NPs), nanofillers (NFs), and bio-nanocomposites.

Metal-based nanoparticles, sensors, and their multifaceted application in food packaging

Due to the global rise of the human population, one of the top-most challenges for poor and developing nations is to use the food produces safely and sustainably. In this regard, the storage of surplus food (and derived products) without loss of freshness, nutrient stability, shelf life, and their parallel efficient utilization will surely boost the food production sector. One of the best technologies that have emerged within the last twenty years with applications in the packaging of food and industrial materials is the use of green mode-based synthesized nanoparticles (NPs). These NPs are stable, advantageous as well as eco-friendly. Over the several years, numerous publications have confirmed that these NPs exert antibacterial, antioxidant, and antifungal activity against a plethora of pathogens. The storage in metal-based NPs (M-NPs) does not hamper the food properties and packaging efficiency. Additionally, these M-NPs help in the improvement of properties including freshness indicators, mechanical properties, antibacterial and water vapor permeability during food packaging. As a result, the nano-technological application facilitates a simple, alternate, interactive as well as reliable technology. It even provides positive feedback to food industries and packaging markets. Taken together, the current review paper is an attempt to highlight the M-NPs for prominent applications of antimicrobial properties, nanosensors, and food packaging of food items. Additionally, some comparative reports associated with M-NPs mechanism of action, risks, toxicity, and overall future perspectives have also been made.

Innovations in nanoscience for the sustainable development of food and agriculture with implications on health and environment

A rapid increase in world population is leading to the rise in global demand of food and agriculture (agri) products. Nanotechnology and its applications have emerged as one of the most pioneering and promising technology for transforming conventional food and agri industries, with the aim of sustainable farming, improving the food security, quality and safety which could revolutionize the food and agri industries. Current developments in nanotechnology have led to the new paths progressively and bringing the radical changes the way food is perceived throughout the farming, transportation, processing, packaging, storage, monitoring and consumption. This review brings the current updates on novel nanomaterials in food and agri industries. Emphasis is given on the importance of nanotechnological applications, offering complete food solutions from farm to fork; including nutraceutical and functional foods, improving bioavailability, efficiency, nutritional status, nano-additives, food texture, color, taste and packaging. Agricultural sector also witnessed several nano-based products, such as nano-fertilizer, nano-pesticide, nano growth promoters and many more for the development of sustainable farming and crop improvement. Despite of numerous advantages of nanotechnology, there are still toxicity challenges, safety concerns, which needs to be addressed and demands transformations in regulatory policies. Rapid development is projected to transform several foods and agri sectors, with rapid increase in market stake and investment. Government agencies, private research centers as well as academicians are also coming together to explore the benefits of nanotechnology to improve food scarcity in the coming years.

Effect of Organic Modifier Types on the Physical-Mechanical Properties and Overall Migration of Post-Consumer Polypropylene/Clay Nanocomposites for Food Packaging

The deterioration of the physical-mechanical properties and loss of the chemical safety of plastics after consumption are topics of concern for food packaging applications. Incorporating nanoclays is an alternative to improve the performance of recycled plastics. However, properties and overall migration from polymer/clay nanocomposites to food require to be evaluated case-by-case. This work aimed to investigate the effect of organic modifier types of clays on the structural, thermal and mechanical properties and the overall migration of nanocomposites based on 50/50 virgin and recycled post-consumer polypropylene blend (VPP/RPP) and organoclays for food packaging applications. The clay with the most hydrophobic organic modifier caused higher thermal stability of the nanocomposites and greater intercalation of polypropylene between clay mineral layers but increased the overall migration to a fatty food simulant. This migration value was higher from the 50/50 VPP/RPP film than from VPP. Nonetheless, clays reduced the migration and even more when the clay had greater hydrophilicity because of lower interactions between the nanocomposite and the fatty simulant. Conversely, nanocomposites and VPP/RPP control films exhibited low migration values in the acid and non-acid food simulants. Regarding tensile parameters, elongation at break values of PP film significantly increased with RPP addition, but the incorporation of organoclays reduced its ductility to values closer to the VPP.

Recent Developments in Chitosan-Based Micro/Nanofibers for Sustainable Food Packaging, Smart Textiles, Cosmeceuticals, and Biomedical Applications

Chitosan has many useful intrinsic properties (e.g., non-toxicity, antibacterial properties, and biodegradability) and can be processed into high-surface-area nanofiber constructs for a broad range of sustainable research and commercial applications. These nanofibers can be further functionalized with bioactive agents. In the food industry, for example, edible films can be formed from chitosan-based composite fibers filled with nanoparticles, exhibiting excellent antioxidant and antimicrobial properties for a variety of products. Processing 'pure' chitosan into nanofibers can be challenging due to its cationic nature and high crystallinity; therefore, chitosan is often modified or blended with other materials to improve its processability and tailor its performance to specific needs. Chitosan can be blended with a variety of natural and synthetic polymers and processed into fibers while maintaining many of its intrinsic properties that are important for textile, cosmeceutical, and biomedical applications. The abundance of amine groups in the chemical structure of chitosan allows for facile modification (e.g., into soluble derivatives) and the binding of negatively charged domains. In particular, high-surface-area chitosan nanofibers are effective in binding negatively charged biomolecules. Recent developments of chitosan-based nanofibers with biological activities for various applications in biomedical, food packaging, and textiles are discussed herein.

Adsorptive removal of enrofloxacin with magnetic functionalized graphene oxide@ metal-organic frameworks employing D-optimal mixture design

A novel sorbent based on a mixture of magnetic functionalized graphene oxide and MOFs was developed to remove enrofloxacin (EFX) from water samples. The prepared sorbent was characterized using Fourier transform infrared spectra, scanning electron microscope images, and X-ray powder diffraction pattern. The sorbent compositions were optimized by the mixture experimental design. Under the optimal condition, the percentages of each sorbent component, including triethylene tetramine-functionalized graphene oxide (FGO), Fe₃ O₄ , and MOF-5, were 40%, 21%, and 39%, respectively. Besides, the intraparticle diffusion and pseudo-second-order kinetic models can describe the EFX adsorption procedure because of two adsorption mechanisms of EFX on FGO and MOF-5. A positive standard enthalpy of 49.80 kJ/mol indicated the EFX adsorption is endothermic with a chemisorption process. The negative values of ΔG^o obtained in the range of -8.979 to -3.431 kJ/mol at all studied temperatures showed that the adsorption process was also spontaneous. The Langmuir and Freundlich isotherm models were analyzed with the partition coefficient to reduce bias in the isotherm model evaluation. The maximum adsorption capacity of 344.83 mg/g and a high partition coefficient of 17.42 g/L in an initial EFX concentration of 10 mg/L were obtained for the EFX removal. PRACTITIONER POINTS: Magnetic functionalized graphene oxide @MOF-5 as a sorbent for the enrofloxacin removal is synthesized. The percentage amount of each component of the sorbent is optimized using the D-optimal mixture design. Adsorption mechanisms of enrofloxacin on magnetic functionalized graphene oxide @MOF-5 are discussed. Thermodynamic parameters for the enrofloxacin adsorption with the sorbents are determined. Isotherm model for the enrofloxacin removal with the sorbent is investigated.

Optimization of antibacterial and mechanical properties of an active LDPE/starch/nanoclay nanocomposite film incorporated with date palm seed extract using D-optimal mixture design approach

A novel active LDPE/TPS nanocomposite films containing date palm seed extracts (Kabkab variety) were developed using D-optimal mixture design. 20 different blends of components including LDPE, TPS, Cloisite 20A, PE-g-MA, EDTA and date palm seed extracts in different proportions were prepared. Using trace and counter plots the effects of each component on the mechanical and antibacterial properties of the composites were studied. The results showed that the films containing a mixture of date seed extract and EDTA had notable antibacterial activity against E. coli and S. aureus; however, these components weakened the mechanical properties of the prepared films. At the same time Cloisite 20A nanoparticles strengthened the films mechanical properties. The optimized formulation for the overall best antibacterial and mechanical properties was 67.5 wt% for LDPE, 4.1 wt% for date seed extract, 2.8 wt% for Cloisite 20A and 2.5 wt% for EDTA. The studied properties of the manufactured film samples were close to the values predicted by the model.

Food packaging and nanotechnology: safeguarding consumer health and safety

Purpose

Nanotechnology as an emerging area if adequately harnessed could revolutionise food packaging and food processing industry worldwide. Although several benefits of nano-materials or particles in food packaging have been suggested, potential risks and health hazards of nano-materials or particles are possible as a result of migration of their particles into food materials. The purpose of this review therefore assessed nanotechnology and its applications in food packaging, consumer acceptability of nano-packaged foods and potential hazards and safety issues in nano-packaged foods.

Design/methodology/approach

This review takes a critical assessment of previous literature on nanotechnology and its impact on food packaging, consumer health and safety.

Findings

Applications of nanotechnology in food packaging could be divided into three main divisions: improved packaging, which involves mixing nano-materials into polymers matrix to improve temperature, humidity and gas barrier resistance of the packaging materials. Active packaging deals with direct interaction between nano-materials used for packaging and the food to protect it as anti-microbial or oxygen or ultra violet scavengers. Smart packaging could be used to sense biochemical or microbial changes in foods, as well as a tracker for food safety, to prevent food counterfeit and adulteration. The review also discussed bio-based food packaging which is biodegradable. Bio-based packaging could serve as veritable alternative to conventional packaging which is non-degradable plastic polymers which are not environmental friendly and could pose a threat to the environment. However, bio-based packaging could reduce material waste, elongate shelf life and enhance food quality. However, several challenges are envisaged in the use of nano-materials in food packaging due to knowledge gaps, possible interaction with food products and possible health risks that could result from the nano-materials used for food packaging.

Originality/value

The increase in growth and utilisation of nanotechnology signifies wide use of nano-materials especially in the food sector with arrays of potential benefits in the areas of food safety and quality, micronutrients and bioactive ingredients delivery, food processing and in packaging Active studies are being carried out to develop innovative packages such as smart, intelligent and active food packaging to enhance effective and efficient packaging, as well as balanced environmental issues. This review looks at the future of nano-packaged foodsvis-à-visthe roles played by stakeholders such as governments, regulatory agencies and manufacturers in looking into consumer health and safety issues related to the application of nano-materials in food packaging.

Influence of Nanocellulose Additive on the Film Properties of Native Rice Starch-based Edible Films for Food Packaging

BACKGROUND & OBJECTIVE

Starch-based edible films, which are transparent, odourless, biodegradable, tasteless, and semi-permeable to gases and food additives, have attracted the attention of the research community as the alternative food packaging materials to synthetic plastics. However, they pose poor water resistance and mechanical strength that should be improved for food packaging application. Few relevant patents to the topic have been reviewed and cited.

METHODS

Inclusion of nanoadditives in starch films can not only improve their mechanical and barrier properties but also can act as antimicrobial agent, oxygen scavenger, and biosensor. The present investigation is focussed on the effects of nanocellulose extracted from banana pseudostems on the film properties of rice starch-based edible films. Nanocellulose was extracted from dried banana pseudostems through isolation of cellulose and acid hydrolysis. Rice starch-based edible films were prepared through solution casting by adding nanocellulose of varying concentrations (0%, 2%, 4%, 6%, 8% & 10%).

RESULTS

The film properties, such as Water Vapour Permeability (WVP), mechanical strength (tensile strength, Young's modulus and percentage of elongation), film solubility in water and film colour, were determined. The test results were discussed and the effects of nanocellulose additives were studied.

CONCLUSION

From the results, it was clear that the addition of nanocellulose had improved the film properties, making the rice starch-based edible films a promising choice for food packaging applications.

Polymeric Nanocomposites and Nanocoatings for Food Packaging: A Review

Special properties of the polymeric nanomaterials (nanoscale size, large surface area to mass ratio and high reactivity individualize them in food packaging materials. They can be processed in precisely engineered materials with multifunctional and bioactive activity. This review offers a general view on polymeric nanocomposites and nanocoatings including classification, preparation methods, properties and short methodology of characterization, applications, selected types of them used in food packaging field and their antimicrobial, antioxidant, biological, biocatalyst and so forth, functions.

The Pros and Cons of the Use of Laser Ablation Synthesis for the Production of Silver Nano-Antimicrobials

Silver nanoparticles (AgNPs) are well-known for their antimicrobial effects and several groups are proposing them as active agents to fight antimicrobial resistance. A wide variety of methods is available for nanoparticle synthesis, affording a broad spectrum of chemical and physical properties. In this work, we report on AgNPs produced by laser ablation synthesis in solution (LASiS), discussing the major features of this approach. Laser ablation synthesis is one of the best candidates, as compared to wet-chemical syntheses, for preparing Ag nano-antimicrobials. In fact, this method allows the preparation of stable Ag colloids in pure solvents without using either capping and stabilizing agents or reductants. LASiS produces AgNPs, which can be more suitable for medical and food-related applications where it is important to use non-toxic chemicals and materials for humans. In addition, laser ablation allows for achieving nanoparticles with different properties according to experimental laser parameters, thus influencing antibacterial mechanisms. However, the concentration obtained by laser-generated AgNP colloids is often low, and it is hard to implement them on an industrial scale. To obtain interesting concentrations for final applications, it is necessary to exploit high-energy lasers, which are quite expensive. In this review, we discuss the pros and cons of the use of laser ablation synthesis for the production of Ag antimicrobial colloids, taking into account applications in the food packaging field.

Metal Oxide Nanostructures in Food Applications: Quality Control and Packaging

Metal oxide materials have been applied in different fields due to their excellent functional properties. Metal oxides nanostructuration, preparation with the various morphologies, and their coupling with other structures enhance the unique properties of the materials and open new perspectives for their application in the food industry. Chemical gas sensors that are based on semiconducting metal oxide materials can detect the presence of toxins and volatile organic compounds that are produced in food products due to their spoilage and hazardous processes that may take place during the food aging and transportation. Metal oxide nanomaterials can be used in food processing, packaging, and the preservation industry as well. Moreover, the metal oxide-based nanocomposite structures can provide many advantageous features to the final food packaging material, such as antimicrobial activity, enzyme immobilization, oxygen scavenging, mechanical strength, increasing the stability and the shelf life of food, and securing the food against humidity, temperature, and other physiological factors. In this paper, we review the most recent achievements on the synthesis of metal oxide-based nanostructures and their applications in food quality monitoring and active and intelligent packaging.

Nanotechnology: An Untapped Resource for Food Packaging

Food commodities are packaged and hygienically transported to protect and preserve them from any un-acceptable alteration in quality, before reaching the end-consumer. Food packaging continues to evolve along-with the innovations in material science and technology, as well as in light of consumer's demand. Presently, the modern consumers of competitive economies demands for food with natural quality, assured safety, minimal processing, extended shelf-life and ready-to-eat concept. Innovative packaging systems, not only ascertains transit preservation and effective distribution, but also facilitates communication at the consumer levels. The technological advances in the domain of food packaging in twenty-first century are mainly chaired by nanotechnology, the science of nano-materials. Nanotechnology manipulates and creates nanometer scale materials, of commercial and scientific relevance. Introduction of nanotechnology in food packaging sector has significantly addressed the food quality, safety and stability concerns. Besides, nanotechnology based packaging intimate's consumers about the real time quality of food product. Additionally, nanotechnology has been explored for controlled release of preservatives/antimicrobials, extending the product shelf life within the package. The promising reports for nanotechnology interventions in food packaging have established this as an independent priority research area. Nanoparticles based food packages offer improved barrier and mechanical properties, along with food preservation and have gained welcoming response from market and end users. In contrary, recent advances and up-liftment in this area have raised various ethical, environmental and safety concerns. Policies and regulation regarding nanoparticles incorporation in food packaging are being reviewed. This review presents the existing knowledge, recent advances, concerns and future applications of nanotechnology in food packaging sector.

Nanocomposites Based on PCL and Halloysite Nanotubes Filled with Lysozyme: Effect of Draw Ratio on the Physical Properties and Release Analysis

Halloysite nanotubes (HNTs) were loaded with lsozyme, as antimicrobial molecule, at a HNTs/lysozyme ratio of 1:1. Such a nano-hybrid was incorporated into a poly (ε-caprolactone) (PCL) matrix at 10 wt % and films were obtained. The nano-composites were submitted to a cold drawn process at three different draw ratios, λ = 3, 4, and 5, where λ is l_{(final length)}/l_{0(initial length)}. Morphology, physical, and barrier properties of the starting nanocomposite and drawn samples were studied, and correlated to the release of the lysozyme molecule. It was demonstrated that with a simple mechanical treatment it is possible to obtain controlled release systems for specific active packaging requirements.

Nano selenium as antioxidant agent in a multilayer food packaging material

Selenium nanoparticles (SeNPs) were incorporated in a flexible multilayer plastic material using a water-base adhesive as vehicle for SeNPs. The antioxidant performance of the original solutions containing spherical SeNPs of 50-60 nm diameter, the adhesive containing these SeNPs, and the final multilayer plastic material to be used as food packaging were quantitatively measured. The radical scavenging capacity due to SeNPs was quantified by a free radical assay developed in the laboratory and by the diphenyl-1-picrylhydrazyl (DPPH) method. DPPH was not efficient to measure the scavenging capacity in the multilayer when the free radical scavenger is not in the surface in contact with it. Several multilayer laminated structures composed by [PET (20 m)-adhesive-LDPE (with variable thickness from 35 to 90 μm)] were prepared and measured, demonstrating for the first time that free radicals derived from oxygen (OH·, O2·, and O2H) cross the PE layer and arrive at the adhesive. SeNPs remain as such after manufacture and the final laminate is stable after 3 months of storage. The antioxidant multilayer is a non-migrating efficient free radical scavenger, able to protect the packaged product versus oxidation and extending the shelf life without being in direct contact with the product. Migration tests of both Se and SeNPs to simulants and hazelnuts demonstrated the non-migrating performance of this new active packaging. Graphical abstract ᅟ.

Novel polystyrene-based nanocomposites by phosphorene dispersion

Polystyrene-based phosphorene nanocomposites were prepared by a solvent blending procedure allowing the embedding of black phosphorus (BP) nanoflakes in the polymer matrix.