Antimicrobial bio-nanocomposites and their potential applications in food packaging

Tannic acid as a multifunctional additive in polysaccharide and protein-based films for enhanced food preservation: A comprehensive review

Fossil-based polymers continue to dominate the market for single-use food packaging, despite increasing concerns about their sustainability. In response, natural and renewable polymers, such as proteins and polysaccharides, are gaining attention as potential alternatives due to their biodegradability and biocompatibility. However, their broader adoption is hindered by the need to improve their mechanical, barrier, and thermal properties. Tannic acid (TA) has emerged as a particularly effective additive for biopolymer-based films, offering strong antioxidant and antimicrobial properties. It also enhances mechanical and barrier characteristics through physical and/or covalent crosslinking. As a result, TA shows great potential as an additive for bioplastics, improving food packaging performance and extending product shelf life, while benefiting both the environment and the food industry. Despite the promising applications of TA, comprehensive reviews that focus on recent developments in its performance and bioactive properties remain limited. This review aims to highlight the effectiveness of TA as both an active ingredient and a crosslinking agent in various biopolymer films, offering valuable insights into its role in sustainable food packaging solutions by critically examining the latest advancements.

Antibacterial Activity of GO-Based Composites Enhanced by Phosphonate-Functionalized Ionic Liquids and Silver

The development of antibiotic-independent antimicrobial materials is critical for addressing bacterial resistance to conventional antibiotics. Currently, there is a lack of comprehensive understanding of ionic liquid-modified composites in antimicrobial applications. Here, we innovatively prepared GO-based composites modified with phosphonate ionic liquids via a series of surface functionalizations. The resulting antibacterial composites exhibit significant broad-spectrum activity against both Gram-negative and Gram-positive bacteria, including drug-resistant strains, with stronger efficacy against Gram-negative species. Additionally, the material features excellent long-term reusability and the ability to inhibit/destroy biofilms, which is vital for combating persistent infections. Mechanistic studies reveal its antibacterial effects through multiple pathways: disrupting bacterial membranes, inducing ROS, and inactivating intracellular substances-mechanisms less likely to promote resistance. Overall, these phosphonate ionic liquid-modified polycationic materials demonstrate substantial potential in treating bacterial infections, offering a promising strategy to tackle antibiotic resistance challenges.

Release kinetics of eugenol and α-tocopherol from carrageenan films for meat preservation

This paper introduces a novel active carrageenan film designed for meat preservation, featuring the release of antioxidants eugenol (Eu) and α-tocopherol (Tp). The film is composed of semi-refined carrageenan, plasticized with 0.9 % glycerol, and reinforced with 10 % cellulose nanofibers derived from waste biomass. Lipid oxidation was measured through TBARS and percent metmyoglobin to evaluate the film's effectiveness in extending the shelf-life and maintaining the quality of meat. The film containing 0.4 % Tp demonstrates superior mechanical properties and thermal stability, achieving a tensile strength of 66.79 MPa and an elongation at break of 46.54 %. Notably, it exhibits a significant antioxidant release rate over 25 days, with TBARS and percent metmyoglobin values of 0.652 and 35.98 %, respectively. These results suggest that this biodegradable packaging solution not only prolongs meat shelf-life but also aligns with sustainable practices in food preservation. The release profiles of Eu and Tp follow a first-order kinetic model, indicating a controlled and sustained release mechanism. Overall, these findings highlight the potential of active films in enhancing food packaging solutions while promoting eco-friendliness.

Solvent induced method for preparation of multi-advantage carrageenan films

Carrageenan has good film-forming characteristics, but it is difficult to simultaneously improve its multiple performances, such as water-resistance, light transmittance and thermal stability. In this study, multi-advantage composite films were prepared by iota-carrageenan and quaternary ammonium surfactants according to solvent induced method. The weight change, FTIR and thermogravimetric analyses of the films before and after solvent inducement indicated that the inorganic counterions of iota-carrageenan were replaced by quaternary ammonium ions. By increasing surfactant content, the charge interaction with iota-carrageenan was enhanced and a new sharp peak appeared in the X-ray diffraction plots. Physical properties such as film thickness, water-resistance, water vapor transmission rate, and mechanical strength in various states were all related to the content of surfactants. In actual application, composite film with the highest waterproof property was able to maintain original state in water at 95 °C for >1.5 h. Meanwhile, composite films can be a water-induced generator with excellent self-charging and stable power output properties. A comparative study of the film transparency in terms of components and surface morphology was carried out. High light transmission, coupled with lower degradation rate in soil, suggests that these films are suitable for use as agricultural greenhouses and mulch films.

Nanotechnology in the manufacturing of sustainable food packaging: a review

At present, there is an escalating concern among consumers regarding the spoilage and safety of food items. Furthermore, the packaging materials used within the packaging industry are typically unsustainable food packaging. To confront this significant challenge, nanotechnology may offer a feasible alternative to standard packaging practices. Several naturally derived polymers are capable of substituting petrochemical-based polymers. The application of biopolymers has demonstrated an ability to prolong the shelf life of food items. However, these materials frequently exhibit limited functionality. The incorporation of nanomaterials can significantly enhance the capabilities of these films. Furthermore, the fields of nanotechnology and food packaging are trending areas of research that hold promise for addressing various challenges within the packaging sector. Integrating nanomaterials into food packaging materials yields significant advantages relative to traditional packaging approaches. It contributes to enhanced food quality and safety, provides consumers with insights into their dietary practices, enables the repair of packaging tears, and increases the longevity of food storage. Incorporating various nanomaterials into biobased films has gained prominence in sustainable food packaging. This review explores the general overview of the historical perspective of nanotechnology. In addition, we addressed the various kinds of nanomaterials involved in food packaging. The functions of nanomaterials in food packaging applications are briefly reviewed. The compilation and discussion highlight the nanotechnology for safe, sustainable, and satisfiable food packaging. Finally, the toxicity, safety, and future trends of the nanomaterials in sustainable food packaging were briefly summarized. This review underscores the necessity of nanotechnology in sustainable food packaging.

Development and characterization of sodium alginate and β-cyclodextrin nanoemulsions encapsulating betel leaf (Piper betle L.) extract for enhanced antimicrobial efficacy against foodborne pathogen

This study aims to investigate the physical stability, droplet size, zeta potential, and antimicrobial properties of nanoemulsions formulated with betel leaf extract using β-cyclodextrin (CD) and sodium alginate (SA) biopolymers. Nanoemulsions with β-cyclodextrin exhibit superior stability at lower temperatures, with limited droplet size, and strong electrostatic repulsion. Morphological images demonstrate the successful encapsulation of betel leaf extract within both biopolymers, highlighting their potential for antimicrobial applications. Both CD and SA nanoemulsions display inhibitory effects on bacterial strains (E. coli, P. aeruginosa, L. monocytogenes, S. aureus, and B. cereus) and fungal growth (A. brasiliensis, R. stolonifer, F. oxysporum, and C. albicans). SA nanoemulsions show higher antimicrobial activity due to H+ ion release, particularly against A. brasiliensis and C. albicans. These findings underscore the potential of betel leaf extract nanoemulsions, especially those with SA, for various antimicrobial applications for sustainable food packaging, highlighting their significance in addressing microbial challenges.

Recent Advances in Cellulose Nanofiber Modification and Characterization and Cellulose Nanofiber-Based Films for Eco-Friendly Active Food Packaging

There is growing interest in the use of bio-based materials as viable alternatives to petrochemical-based packaging. However, the practical application of bio-based films is often hampered by their poor barrier and poor mechanical properties. In this context, cellulose nanofibers (CNFs) have attracted considerable attention owing to their exceptional biodegradability, high aspect ratio, and large surface area. The extraction of CNFs from agricultural waste or non-food biomass represents a sustainable approach that can effectively balance cost and environmental impacts. The functionalization of CNFs improves the economics of raw materials and production processes while expanding their applications. This paper reviews recent advances in cellulose nanofibers, including their sources, surface modification, and characterization techniques. Furthermore, we systematically discuss the interactions of CNFs with different composites in the development of functional food films. Finally, we highlight the application of cellulose nanofiber films in food preservation. Due to their environmentally friendly properties, CNFs are a promising alternative to petroleum-based plastics. The aim of this paper is to present the latest discoveries and advances in CNFs while exploring the future prospects for edible food films, thereby encouraging further research and application of CNFs in the field of active food packaging.

Effect of silver nanoparticles in polyethylene packaging on physicochemical, microbiological, and textural properties of oil cake

This study investigated silver nanoparticle (SNP)/titanium dioxide polyethylene films as chemical preservative substitutes to increase the shelf life of oil cake. The research examined three types of packaging films: standard low-density polyethylene (LDPE), LDPE with 3% SNP, and LDPE with 5% SNP, and assessed their impact on oil cake shelf life. Analysis of packaging films included scanning and transmission electron microscopy (SEM and TEM), and Fourier-transform infrared spectroscopy. The study evaluated the effects of SNP on chemical and microbial stability on oil cakes in different storage days (1st, 15th, 30th, and 37th days) at 25 °C. Parameters such as moisture content, water vapor permeability, water activity, peroxide, fat acidity, texture, and microorganisms were studied. The results demonstrated that SNP-containing films can extend the shelf life of oil cake up to 37 days, marked by a significant decrease in microbial growth, particularly mold, compared to conventional packaging films. Notably, films with 5% SNP concentrations exhibited the highest efficacy in preserving the quality of the oil cake. Higher concentrations of SNP led to an increased reduction in microbial load and enhanced mold control while maintaining favorable quality assessment indices throughout the storage period from day 1 to day 30. Remarkably, oil cake packaged with a 5% SNP polymer film displayed the most promising outcomes, extending shelf life up to 30 days at 25 °C.

Poly (lactic acid)/ amine grafted mesoporous silica-based composite for food packaging application

The present study focuses on the development of environmentally friendly bio-composite films using poly(lactic acid) (PLA) as a biopolymer matrix. This is achieved by incorporating amine functionalized green mesoporous silica (GMS) and employing a solution casting method for film fabrication. The motivation behind the work is to improve the compatibility between PLA and green mesoporous silica sourced from rice husk by functionalizing GMS with APTES (3-Aminopropyltriethoxy silane). The primary objective is to explore how the inclusion of GMS influences both the physicochemical attributes and the efficacy of active food packaging in PLA. The introduction of GMS to the PLA matrix not only improves the flexibility of PLA/GMS composite films but also enhances their overall performance. The reinforcement of GMS in the PLA matrix has also significantly contributed towards the reduction in oxygen transmittance rate and provided an anti-bacterial effect towards pathogen i.e. S. aureus and E. coli. The PLA/GMS composite films exhibit antioxidant activity acting as potential scavengers with around 78 % efficacy against DPPH (2,2-diphenyl-1-picrylhydrazyl). Consequently, the PLA/GMS composite formulation proposed in this study shows promising outcomes in terms of strength, flexibility, antioxidant properties, and antibacterial characteristics. Also, the PLA/GMS films extended the shelf life of cut apple samples for seven days.

Anti-Helicobacter pylori activity of nanocomposites from chitosan/broccoli mucilage/selenium nanoparticles

Helicobacter pylori can infect most people worldwide to cause hazardous consequences to health; the bacteria could not easily be controlled or disinfected. Toward exploring of innovative biocidal nanoformulations to control H. pylori, broccoli seeds (Brassica oleracea var. italica) mucilage (MBS) was employed for biosynthesizing selenium nanoparticles (MBS/SeNPs), which was intermingled with chitosan nanoparticles (NCT) to generate bioactive nanocomposites for suppressing H. pylori. The MBS could effectually generate and stabilize SeNPs with 13.61 nm mean diameter, where NCT had 338.52 nm mean diameter and positively charged (+ 39.62 mV). The cross-linkages between NCT-MBS-SeNPs were verified via infrared analysis and the nanocomposites from NCT:MBS/SeNPs at 1:2 (T1), 1:1 (T2) and 2:1 (T3) ratios had mean diameters of 204, 132 and 159 nm, respectively. The entire nanomaterials/composites exhibited potent anti- H. pylori activities using various assaying methods; the T2 nanocomposite was the utmost bactericidal agent with 0.08-0.10 mg/L minimal concentration and 25.9-27.3 mm inhibition zones. The scanning microscopy displayed the ability of nanocomposite to attach the bacterial cells, disrupt their membranes, and completely lyse them within 10 h. The NCT/MBS/SeNPs nanocomposites provided effectual innovative approach to control H. pylori.

The preparation, resources, applications, and future trends of nanofibers in active food packaging: a review

Active packaging is a novel strategy for maintaining the shelf life of products and ensuring their safety, freshness, and integrity that has emerged with the consumer demand for safer, healthier, and higher quality food. Nanofibers have received a lot of attention for the application in active food packaging due to their high specific surface area, high porosity, and high loading capacity of active substances. Three common methods (electrospinning, solution blow spinning, and centrifugal spinning) for the preparation of nanofibers in active food packaging and their influencing parameters are presented, and advantages and disadvantages between these methods are compared. The main natural and synthetic polymeric substrate materials for the nanofiber preparation are discussed; and the application of nanofibers in active packaging is elaborated. The current limitations and future trends are also discussed. There have been many studies on the preparation of nanofibers using substrate materials from different sources for active food packaging. However, most of these studies are still in the laboratory research stage. Solving the issues of preparation efficiency and cost of nanofibers is the key to their application in commercial food packaging.

Characterization of antimicrobial multilayer film based on ethylcellulose-pectin incorporated with nanoemulsions of trans-cinnamaldehyde essential oil

In this study, polymer solution casting was utilized to fabricate a multilayer film with ethylcellulose (EC) as the outer layers and trans-cinnamaldehyde-loaded pectin as the inner layer. A significant increase in whiteness and UV-visible light blocking capability and a remarkable decrease in total color difference and yellowness of the films were seen via increasing the thickness of EC outer layers. Scanning electronic microscopy observation showed that the inner and outer layers had a smooth and uniform surfaces with clear boundary. The thicker film has better stretchability and strength, but is less flexible than thinner film. Glass transition temperature did not change remarkably with increasing thickness of EC outer layers, but thermal stability was slightly improved. FTIR-ATR spectra revealed the formation of hydrogen bonds between the two adjacent layers. The multilayer films exhibited excellent antimicrobial efficacy against Gram-positive and Gram-negative foodborne pathogens. The results suggested that this multilayer film has potential applications in active food packaging.

Nano-enabled smart and functional materials toward human well-being and sustainable developments

Fabrication and operation on increasingly smaller dimensions have been highly integrated with the development of smart and functional materials, which are key to many technological innovations to meet economic and societal needs. Along with researchers worldwide, the Waterloo Institute for Nanotechnology (WIN) has long realized the synergetic interplays between nanotechnology and functional materials and designated 'Smart & Functional Materials' as one of its four major research themes. Thus far, WIN researchers have utilized the properties of smart polymers, nanoparticles, and nanocomposites to develop active materials, membranes, films, adhesives, coatings, and devices with novel and improved properties and capabilities. In this review article, we aim to highlight some of the recent developments on the subject, including our own research and key research literature, in the context of the UN Sustainability development goals.

Recent progress on Pickering emulsion stabilized essential oil added biopolymer-based film for food packaging applications: A review

Nowadays food safety and protection are a growing concern for food producers and food industry. The stability of food-grade materials is key in food processing and shelf life. Pickering emulsions (PEs) have gained significant attention in food regimes owing to their stability enhancement of food specimens. PE can be developed by high and low-energy methods. The use of PE in the food sector is completely safe as it uses solid biodegradable particles to stabilize the oil in water and it also acts as an excellent carrier of essential oils (EOs). EOs are useful functional ingredients, the inclusion of EOs in the packaging film or coating formulation significantly helps in the improvement of the shelf life of the packed food item. The highly volatile nature, limited solubility and ease of oxidation in light of EOs restricts their direct use in packaging. In this context, the use of PEs of EOs is suitable to overcome most of the challenges, Therefore, recently there have been many papers published on PEs of EOs including active packaging film and coatings and the obtained results are promising. The current review amalgamates these studies to inform about the chemistry of PEs followed by types of stabilizers, factors affecting the stability and different high and low-energy manufacturing methods. Finally, the review summarizes the recent advancement in PEs-added packaging film and their application in the enhancement of shelf life of food.

Valorization of edible films based on chitosan/hydroxyethyl cellulose/olive leaf extract and TiO2-NPs for preserving sour cream

Biodegradable edible films for sour cream packaging were developed based on chitosan (CS), hydroxyethyl cellulose (HEC), Olive leaf extract (OE), and titanium dioxide nanoparticles (TiO2-NPs). The prepared CS/HEC/TiO2-OE bionanocomposite films were evaluated for their antimicrobial and antioxidant activities as well as using FT-IR, mechanical, permeability, and contact angle. The effect of developed films on the lipid oxidation, microbiological load, and chemical properties of sour cream was investigated. The fabricated films had an antimicrobial impact against all tested strains. The film containing 8 % OE showed effective protection against fat oxidation, with a peroxide value of 3.21 meq O2/kg, a para-anisidine value 5.40, and free fatty acids of 0.82 mg KOH/kg. The films with OE 4 % and 8 % have a good effect on the microbiological load of sour cream for 90 days. These films did not influence the chemical composition of sour cream and therefore can be used in this sort of dairy product.

Green synthesis of nanocellulose supported cu-bionanocomposites and their profound applicability in the synthesis of amide derivatives and controlling of food-borne pathogens

Copper bionanocomposites (CBNCS) were synthesized using Ipomoea carnea- sourced nanocellulose as support via an eco-friendly and cost-effective method. X-ray Diffractometer (XRD) pattern of CBNCS confirmed the octahedral structure of Cu2O, the face-centered cubic (FCC) crystal structure of Cu(0). XRD also revealed the crystal lattice of cellulose II. Surface Electron Microscope (SEM) and Transmission Electron Microscope (TEM) revealed the uniform distribution of copper nanoparticles (Cu NPs) with an average size of 10 nm due to the presence of nanocellulose. X-ray photoelectron spectroscopy (XPS) provided information about the electronic, chemical state and elemental composition of CBNCS. Thermogravimetric Analysis (TGA) showed the thermal stability of CBNCS. CBNCS catalyzed the rearrangement of oximes to primary amides in a very mild condition with a high yield of up to 92 %. CBNCS effectively inhibited the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with lower minimum inhibitory concentration MIC values. Antioxidant activity and electrical conductivity of CBNCS were also determined.

A data mining approach to analyze the role of biomacromolecules-based nanocomposites in sustainable packaging

Recent decades have witnessed a surge in research interest in bio-nanocomposite-based packaging materials, but still, a lack of systematic analysis exists in this domain. Bio-based packaging materials pose a sustainable alternative to petroleum-based packaging materials. The current work employs bibliometric analysis to deliver a comprehensive outline on the role of bio nanocomposites in packaging. India, Iran, and China were revealed to be the top three nations actively engaged in this domain in total publications. Islamic Azad University in Iran and Universiti Putra Malaysia in Malaysia are among the world's best institutions in active research and publications in this field. The extensive collaboration between nations and institutions highlights the significance of a holistic approach towards bio-nanocomposite. The National Natural Science Foundation of China is the leading funding body in this field of research. Among authors, Jong whan Rhim secured the topmost citations (2234) in this domain (13 publications). Among journals, Carbohydrate Polymers secured the maximum citation count (4629) from 36 articles; the initial one was published in 2011. Bio nanocomposite is the most frequently used keyword. Researchers and policymakers focussing on sustainable packaging solutions will gain crucial insights on the current research status on packaging solutions using bio-nanocomposites from the conclusions.

Edible packaging as sustainable alternative to synthetic plastic: a comprehensive review

The choice of an appropriate packaging materials enhances the shelf life and improves quality of food during transportation, storage, and distribution. Development and innovations in food packaging systems have become essential in the food industry. Most widely used packaging materials are non-biodegradable plastics and are harmful to environment and human health. Thus, food industry is replacing non-biodegradable plastics with biodegradable plastics to reduce environmental pollution, health hazards, and food waste. Edible packaging may reduce food waste and keep perishables fresh. This review article compares edible packaging materials to synthetic ones and discusses their pollution-reducing effects. The several types of food packaging discussed in the review include those produced from polysaccharides, proteins, lipids, and composite films. The various characteristics of edible packaging are reviewed, including its barrier qualities, carrier properties, mechanical capabilities, and edibility. The carrier properties describe the capacity to transport and manage the release of active substances, and the edibility indicates acceptance of these items by the customers. Plasticizers, antimicrobials, antioxidants, and emulsifiers were included in the edible packaging to enhance the characteristics of the film. The development and implementation of edible packaging on food products from the laboratory to large-scale industrial levels, as well as their potential industrial applications in the dairy, meat, confectionary, poultry, fish, fruit, and vegetable processing sectors are addressed.

Unlocking sustainable solutions: Nanocellulose innovations for enhancing the shelf life of fruits and vegetables - A comprehensive review

Regarding food security and waste reduction, preserving fruits and vegetables is a vital problem. This comprehensive study examines the innovative potential of coatings and packaging made of nanocellulose to extend the shelf life of perishable foods. The distinctive merits of nanocellulose, which is prepared from renewable sources, include exceptional gas barrier performance, moisture retention, and antibacterial activity. As a result of these merits, it is a good option for reducing food spoilage factors such as oxidation, desiccation, and microbiological contamination. Nanocellulose not only enhances food preservation but also complies with industry-wide environmental objectives. This review explores the many facets of nanocellulose technology, from its essential characteristics to its use in the preservation of fruits and vegetables. Furthermore, it deals with vital issues including scalability, cost-effectiveness, and regulatory constraints. While the use of nanocellulose in food preservation offers fascinating potential, it also wants to be cautiously careful to assure affordability, effectiveness, and safety. To fully use the potential of nanocellulose and advance the sustainability plan in the food business, collaboration between scientists, regulatory bodies, and industry stakeholders is important as we stand on the cusp of a revolutionary era in food preservation.

Sulfonated cellulose nanocrystal modified with ammonium salt as reinforcement in poly(lactic acid) composite films

Poly(lactic acid) (PLA) composites reinforced with cellulose nanocrystals (CNCs) are promising biodegradable materials. However, the poor compatibility and dispersion of CNCs in the PLA matrix remain a significant obstacle to improving the properties of composites. In this study, the modified CNC (CNC-D) was prepared through sulfonation treatment, followed by modification with didecyl dimethyl ammonium chloride (DDAC). Then, CNC-D was mixed with PLA to prepare composite films (PLA-CNC-D). The results revealed that the PLA-CNC-D had higher tensile strength and elongation at break than PLA-CNC at 3 wt% nanofiller content, increasing by 41.53 and 22.18 %, respectively. SEM and DSC analysis indicated that surface modification improved the compatibility and dispersion of CNC-D in the PLA matrix. The sulfonation process increased the anion content on the surface of CNC-D, enabling the CNC-D surface to adsorb more cationic DDAC, consequently sharply reducing the hydrophilicity of CNC-D. Moreover, the PLA-CNC-D exhibited excellent antibacterial activity against S. aureus and E. coli. In summary, this study provides a novel CNC modification approach to enhance the physical properties and antibacterial activity of PLA composite films, enlarging the application of degradable PLA composites.

Synthesis of Novel Nanocomposite Materials with Enhanced Antimicrobial Activity based on Poly(Ethylene Glycol Methacrylate)s with Ag, TiO2 or ZnO Nanoparticles

The aim of this investigation was to prepare novel hybrid materials with enhanced antimicrobial properties to be used in food preservation and packaging applications. Therefore, nanocomposite materials were synthesized based on two stimuli-responsive oligo(ethylene glycol methacrylate)s, namely PEGMA and PEGMEMA, the first bearing hydroxyl side groups with three different metal nanoparticles, i.e., Ag, TiO2 and ZnO. The in situ radical polymerization technique was employed to ensure good dispersion of the nanoparticles in the polymer matrix. FTIR spectra identified the successful preparation of the corresponding polymers and XRD scans revealed the presence of the nanoparticles in the polymer matrix. In the polymer bearing hydroxyl groups, the presence of Ag-NPs led to slightly lower thermal stability as measured by TGA, whereas both ZnO and TiO2 led to nanomaterials with better thermal stability. The antimicrobial activity of all materials was determined against the Gram-negative bacteria E. coli and the Gram-positive S. aureus, B. subtilis and B. cereus. PEGMEMA nanocomposites had much better antimicrobial activity compared to PEGMA. Ag NPs exhibited the best inhibition of microbial growth in both polymers with all four bacteria. Nanocomposites with TiO2 showed a very good inhibition percentage when used in PEGMEMA-based materials, while in PEGMA material, high antimicrobial activity was observed only against E. coli and B. subtilis, with moderate activity against B. cereus and almost absent activity against S. aureus. The presence of ZnO showed antimicrobial activity only in the case of PEGMEMA-based materials. Differences observed in the antibacterial activity of the polymers with the different nanoparticles could be attributed to the different structure of the polymers and possibly the more efficient release of the NPs.

Formation and detection of biocoronas in the food industry and their fate in the human body

The rapid advancement of nanotechnology has opened up new avenues for applications in all stages of the food industry. Over the past decade, extensive research has emphasized that when nanoparticles (NPs) enter organisms, they spontaneously adsorbed biomolecules, leading to the formation of biocorona. This paper provided a detailed review of the process of biocorona formation in the food industry, including their classification and influencing factors. Additionally, various characterization methods to investigated the morphology and structure of biocoronas were introduced. As a real state of food industry nanoparticles in biological environments, the biocorona causes structural transformations of biomolecules bound to NPs, thus affecting their fate in the body. It can either promote or inhibit enzyme activity in the human environment, and may also positively or negatively affect the cellular uptake and toxicity of NPs. Since NPs present in the food industry will inevitably enter the human body, further investigations on biocoronas will offer valuable insights and perspectives on the safety of incorporating more NPs into the food industry.

Roles of polysaccharides-based nanomaterials in food preservation and extension of shelf-life of food products: A review

In food production sectors, food spoilage and contamination are major issues that threaten and negatively influence food standards and safety. Several physical, chemical, and biological methods are used to extend the shelf-life of food products, but they have their limitations. Henceforth, researchers and scientists resort to novel methods to resolve these existing issues. Nanomaterials-based extension of food shelf life has broad scope rendering a broad spectrum of activity including high antioxidant and antimicrobial activity. Numerous research investigations have been made to identify the possible roles of nanoparticles in food preservation. A wide range of nanomaterials via different approaches is ultimately applied for food preservation. Among them, chemically synthesized methods have several limitations, unlike biological synthesis. However, biological synthesis protocols are quite expensive and laborious. Predominant studies demonstrated that nanoparticles can protect fruits and vegetables by preventing microbial contamination. Though several nanomaterials designated for food preservation are available, detailed knowledge of the mechanism remains unclear. Hence, this review aims to highlight the various nanomaterials and their roles in increasing the shelf life of food products. Adding to the novel market trends, nano-packaging will open new frontiers and prospects for ensuring food safety and quality.

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.

Performance analysis and structural characterization of flaxseed gum/chitosan/cinnamaldehyde composite films

The low mechanical strength, water deficiency, and oxidative protection of organic membranes impede their use as food-grade packaging materials. Cinnamaldehyde (CIN) tends to lose its activity owing to its instability. In this study, CIN was added to flaxseed gum (FG)/chitosan (CS) films prepared in a "sandwich" structure. The influence of CIN dosage on the properties of the composite films was studied, and the film formation mechanism of the membrane was explored. The elongation at break, water vapor permeability, oxygen permeability, and light transmittance of the composite film with 1.5% CIN were lower than those of the FG/CS/FG film. Supplementation of the composite membrane with CIN generated new hydrogen bonds, electrostatic interactions, and C-O-C bonds, which converted the structure of the composite film into a sheet and increased its crystallinity without markedly affecting its thermal stability. Therefore, CIN is an extremely useful additive for improving the applicability of flaxseed gum/CS membranes as food-grade packaging films.

Obtention and Study of Polyurethane-Based Active Packaging with Curcumin and/or Chitosan Additives for Fruits and Vegetables-Part I: Analysis of Morphological, Mechanical, Barrier, and Migration Properties

Several polyurethane-formulated films with curcumin and/or chitosan additives for food packaging have been previously obtained. The study examines the effect of the additives on the film's morphological, mechanical, barrier, and migration properties. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), water contact angle, thermogravimetric and differential thermal analysis (TGA and DTGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), oxygen transmission rate (OTR), water vapor transmission rate (WVTR), and the overall and specific migration tests were conducted. The results show that the presence of chitosan significantly increased the overall migration and mechanical properties, such as the elongation at break, tensile strength, and Young's modulus of most polyurethane formulations, while curcumin had a minor influence on the mechanical performance. Based on the results, formulations with curcumin but without chitosan are suitable for food packaging.

Edible Coatings and Future Trends in Active Food Packaging-Fruits' and Traditional Sausages' Shelf Life Increasing

The global food production industry faces environmental concerns exacerbated by substantial food waste. European countries are striving to reduce food waste towards a circular bioeconomy and sustainable development. To address environmental issues and reduce plastic waste, researchers are developing sustainable active packaging systems, including edible packaging made from industry residues. These innovations aim to increase food safety and quality, extend shelf life, and reduce plastic and food waste. Particularly important in the context of the growing demand for fresh and minimally processed fruits, edible coatings have emerged as a potential solution that offers numerous advantages in maintaining fruit quality. In addition to fruit, edible coatings have also been investigated for animal-based foods to meet the demand for high-quality, chemical-free food and extended shelf life. These products globally consumed can be susceptible to the growth of harmful microorganisms and spoilage. One of the main advantages of using edible coatings is their ability to preserve meat quality and freshness by reducing undesirable physicochemical changes, such as color, texture, and moisture loss. Furthermore, edible coatings also contribute to the development of a circular bioeconomy, promoting sustainability in the food industry. This paper reviews the antimicrobial edible coatings investigated in recent years in minimally processed fruits and traditional sausages. It also approaches bionanocomposites as a recently emerged technology with potential application in food quality and safety.

Electrospun Nanofibers for Functional Food Packaging Application

With the strengthening of the public awareness of food safety and environmental protection, functional food packaging materials have received widespread attention. Nanofibers are considered as promising packaging materials due to their unique one-dimensional structure (high aspect ratio, large specific surface area) and functional advantages. Electrospinning, as a commonly used simple and efficient method for preparing nanofibers, can obtain nanofibers with different structures such as aligned, core-shell, and porous structures by modifying the devices and adjusting the process parameters. The selection of raw materials and structural design of nanofibers can endow food packaging with different functions, including antimicrobial activity, antioxidation, ultraviolet protection, and response to pH. This paper aims to provide a comprehensive review of the application of electrospun nanofibers in functional food packaging. Advances in electrospinning technology and electrospun materials used for food packaging are introduced. Moreover, the progress and development prospects of electrospun nanofibers in functional food packaging are highlighted. Meanwhile, the application of functional packaging based on nanofibers in different foods is discussed in detail.

Active Cellulose Acetate/Chitosan Composite Films Prepared Using Solution Blow Spinning: Structure and Electrokinetic Properties

Cellulose acetate (CA), a very promising derivative of cellulose, has come into the focus of research due to its highly desired good film-forming ability for food packaging applications. Frequently, this derivative is used in combination with other compounds (polymers, nanoparticles) in order to obtain active materials. Here, we report the preparation of thin films made of cellulose acetate loaded with chitosan (CS) using the solution blow spinning (SBS) method. Films are prepared by SBS processing of the polymers mixture solution, considering the following variables: (i) the concentration of cellulose acetate and chitosan in the solution and (ii) the solvent system consisting of acetic or formic acid. The prepared materials are characterized in terms of physical properties, roughness (optical profilometer), porosity, wettability (contact angle measurements), chemical structure (Fourier transform infrared spectrometry), and electrokinetic properties (zeta potential). SBS enables the preparation of CA/CS films with high water vapor permeability, high porosity, and also higher water contact angle compared with pure CA films. The electrokinetic properties of composites are influenced by the inclusion of chitosan, which causes a shift of the isoelectric point (IEP) towards higher pH values, but the magnitude of the shift is not in correlation with chitosan concentration. Adsorption kinetic studies using bovine serum albumin (BSA) as a model protein reveal that chitosan modified cellulose acetate films manifest low affinity towards proteins that suggests prevention of biofilm formation on its surface.

Graphene Nanocomposites as Innovative Materials for Energy Storage and Conversion-Design and Headways

This review mainly addresses applications of polymer/graphene nanocomposites in certain significant energy storage and conversion devices such as supercapacitors, Li-ion batteries, and fuel cells. Graphene has achieved an indispensable position among carbon nanomaterials owing to its inimitable structure and features. Graphene and its nanocomposites have been recognized for providing a high surface area, electron conductivity, capacitance, energy density, charge-discharge, cyclic stability, power conversion efficiency, and other advanced features in efficient energy devices. Furthermore, graphene-containing nanocomposites have superior microstructure, mechanical robustness, and heat constancy characteristics. Thus, this state-of-the-art article offers comprehensive coverage on designing, processing, and applying graphene-based nanoarchitectures in high-performance energy storage and conversion devices. Despite the essential features of graphene-derived nanocomposites, several challenges need to be overcome to attain advanced device performance.

Control of release in active packaging/coating for food products; approaches, mechanisms, profiles, and modeling

Antimicrobial or antioxidant active packaging (AP) is an emerging technology in which a bioactive antimicrobial or antioxidant agent is incorporated into the packaging material to protect the contained product during its shelf life from deterioration. The important issue in AP is making a balance between the deterioration rate of the food product and the controlled release of the bioactive agent. So, the AP fabrication should be designed in such a way that fulfills this goal. Modeling the controlled release is an effective way to avoid trial and error and time-consuming experimental runs and predict the release behavior of bioactive agents in different polymeric matrices and food/food simulants. To review the release of bioactive compounds from AP, in the first part of this review we present an introductory explanation regarding the release controlling approaches in AP. Then the release mechanisms are explained which are very important in defining the appropriate modeling approach and also the interpretation of the modeling results. Different release profiles that might be observed in different packaging systems are also introduced. Finally, different modeling approaches including empirical and mechanistic techniques are covered and the recent literature regarding the utilization of such approaches to help design new AP is thoroughly studied.

Synthesis, characterization and antifungal potential of titanium dioxide nanoparticles against fungal disease (Ustilago tritici) of wheat (Triticum aestivum L.)

Nanoparticles (NPs) preparation using a green as well as environmentally acceptable processes has achieved a lot of attention in recent decade. The current study compared the synthesis of titania (TiO₂) nanoparticles synthesized from leaf extracts of two plant species (Trianthema portulacastrum, Chenopodium quinoa) and traditional approach by chemical preparation. The effects of no calcination on the physical characteristics of TiO₂ NPs as well as their antifungal effects were examined and compared with the already reported calcinated TiO₂ NPs. The produced TiO₂ NPs were evaluated using high-tech techniques such as X-ray diffraction (XRD), scanning electron microscope, energy dispersive spectroscopy (EDX), and elemental mapping. TiO₂ NPs prepared by sol-gel technique (T1) and prepared from extractions from leaves of T. portulacastrum (T2), and C. quinoa (T3) were either calcinated or non calcinated and tested against fungal disease (Ustilago tritici) of wheat for antifungal efficacy. The -peak (2θ) at 25.3 was confirmed by XRD to be connected with the anatase (101) form in both cases but before calcination, NPs were lacking the rutile and brookite peaks. The results showed that all types of TiO₂ NPs examined had good antifungal activity against U. tritici, but those made from C. quinoa plant extract have good antifungal activity against disease. TiO₂ NPs which are produced by the green methods (T2, T3) have the highest antifungal activity (58%, 57% respectively), while minimal activity (19%) was recorded when NPs were synthesized using the sol-gel method (T1) with 25 μl/mL. Non calcinated TiO₂ NPs have less antifungal potential than calcined TiO₂ NPs. It can be concluded that calcination may be preferred for efficient antifungal activity when using titania nanoparticles. The green technology may be used on a larger scale with less damaging TiO₂ NP production and can be utilized against fungal disease on wheat crop to reduce crop losses worldwide.

Gelatin Improves the Performance of Oregano Essential Oil Nanoparticle Composite Films-Application to the Preservation of Mullet

In this study, the addition of oregano oil chitosan nanoparticles (OEO-CSNPs) was conducted to enhance the comprehensive properties of gelatin films (GA), and the optimal addition ratio of nanoparticles was determined for its application in the preservation of mullet. Oregano oil chitosan nanoparticles were organically combined with gelatin at different concentrations (0%, 2%, 4%, 6% and 8%) to obtain oregano oil-chitosan nanoparticle-GA-based composite films (G/OEO-CSNPs), and thereafter G/OEO-CSNPs were characterized and investigated for their preservative effects on mullet. Subsequent analysis revealed that OEO-CSNPs were uniformly dispersed in the GA matrix, and that G/OEO-CSNPs had significantly improved mechanical ability, UV-visible light blocking performance and thermal stability. Furthermore, the nanoparticles exhibited excellent antioxidant and antibacterial properties, and they improved the films' suitability as edible packaging. The attributes of the G/OEO-CSNPs were optimized, the films had the strongest radical scavenging and lowest water solubility, and electron microscopy also showed nanoparticle penetration into the polymer when the concentration of OEO-CSNPs was 6% (thickness = 0.092 ± 0.001, TS = 47.62 ± 0.37, E = 4.06 ± 0.17, water solubility = 48.00 ± 1.11). Furthermore, the GA-based composite film containing 6% OEO-CSNPs was able to inhibit microbial growth, slow fat decomposition and protein oxidation, reduce endogenous enzyme activity, and delay the spoilage of mullet during the refrigeration process, all of which indicate its excellent potential for meat preservation application.

Wood Cellulose Nanofibers Grafted with Poly(ε-caprolactone) Catalyzed by ZnEu-MOF for Functionalization and Surface Modification of PCL Films

Renewable cellulose nanofiber (CNF)-reinforced biodegradable polymers (such as polycaprolactone (PCL)) are used in agriculture, food packaging, and sustained drug release. However, the interfacial incompatibility between hydrophilic CNFs and hydrophobic PCL has limited further application as high-performance biomaterials. In this work, using a novel ZnEu-MOF as the catalyst, graft copolymers (GCL) with CNFs were grafted with poly(ε-caprolactone) (ε-CL) via homogeneous ring-opening polymerization (ROP), and used as strengthening/toughening nanofillers for PCL to fabricate light composite films (LCFs). The results showed that the ZnEu-MOF ([ZnEu(L)₂(HL)(H₂O)_0.39(CH₃OH)_0.61]·H₂O, H₂L is 5-(1H-imidazol-1-yl)-1,3-benzenedicarboxylic acids) was an efficient catalyst, with low toxicity, good stability, and fluorescence emissions, and the GCL could efficiently promote the dispersion of CNFs and improve the compatibility of the CNFs and PCL. Due to the synergistic effect of the ZnEu-MOF and CNFs, considerable improvements in the mechanical properties and high-intensity fluorescence were obtained in the LCFs. The 4 wt% GCL provided the LCF with the highest strength and elastic modulus, which increased by 247.75% and 109.94% compared to CNF/PCL, respectively, showing the best elongation at break of 917%, which was 33-fold higher than CNF/PCL. Therefore, the ZnEu-MOF represented a novel bifunctional material for ROP reactions and offered a promising modification strategy for preparing high-performance polymer composites for agriculture and biomedical applications.

Effect of Kaolin clay and Ficus carica mediated silver nanoparticles on chitosan food packaging film for fresh apple slice preservation

In this work, a novel antioxidant, antibacterial, and biodegradable food packaging film was elaborated, by incorporating natural kaolin clay (KC) and Ficus carica mediated silver nanoparticles (AgNPs) into Chitosan (Cht). A comparison of the physico-chemical and functional characteristics of the Cht/KC/AgNPs film was performed with those of Cht, Cht/KC, and Cht/AgNPs. SEM analysis showed a rough surface in the composite films containing KC particles because of their large diameter (50-120 μm) compared to AgNPs (20-80 nm). The FTIR analysis suggested that the interactions between Cht and AgNPs were stronger than those between Cht and KC. The tensile strength of Cht film increased from 16 MPa to ∼24 MPa in Cht/KC/AgNPs film. The introduction of KC and/or AgNPs considerably improved the light and moisture barrier capacity of the Cht film. The UV light transmittance decreased by 50 % for Cht film when incorporated by KC and AgNPs. Moreover, Cht/AgNPs was better in terms of antioxidant, antibacterial, and mechanical compared to Cht/KC, which was superior in biodegradability and water vapor barrier capacity. In particular, the Cht/KC/AgNPs film presented good barrier, antioxidants, antibacterial, mechanical, and biodegradable properties, owing to the synergistic effect between KC and AgNPs. For the packaging properties, all the films were tested for their ability to keep the freshness of apple slices as wrapping material. The films exhibited good results, and the Cht/KC/AgNPs showed promising performance regarding the moisture loss, browning index, total phenolic compound, and antioxidant activity of the apple slices. Moreover, the Cht/KC/AgNPs film exhibited a migration of silver meeting the standards set by EFSA and ECHA, which makes this film safe for food packaging.

Nanoemulsion-Based Multilayer Films for Ground Beef Preservation: Antimicrobial Activity and Physicochemical Properties

This study aimed to improve the physical, mechanical, and biological properties of a monolayer pectin (P) film containing nanoemulsified trans-Cinnamaldehyde (TC) by incorporating it between inner and outer layers of ethylcellulose (EC). The nanoemulsion had an average size of 103.93 nm and a zeta potential of -46 mV. The addition of the nanoemulsion increased the opacity of the film, reduced its moisture absorption capacity, and improved its antimicrobial activity. However, the tensile strength and elongation at break of the pectin films decreased after the incorporation of nanoemulsions. Multilayer films (EC/P/EC) showed a higher resistance to breaking and better extensibility compared to monolayer films. The antimicrobial activity of both mono and multilayer films was effective in inhibiting the growth of foodborne bacteria during storage of ground beef patties at 8 °C for 10 days. This study suggests that biodegradable antimicrobial multilayer packaging films can be effectively designed and applied in the food packaging industry.

Current Applications of Bionanocomposites in Food Processing and Packaging

Nanotechnology advances are rapidly spreading through the food science field; however, their major application has been focused on the development of novel packaging materials reinforced with nanoparticles. Bionanocomposites are formed with a bio-based polymeric material incorporated with components at a nanoscale size. These bionanocomposites can also be applied to preparing an encapsulation system aimed at the controlled release of active compounds, which is more related to the development of novel ingredients in the food science and technology field. The fast development of this knowledge is driven by consumer demand for more natural and environmentally friendly products, which explains the preference for biodegradable materials and additives obtained from natural sources. In this review, the latest developments of bionanocomposites for food processing (encapsulation technology) and food packaging applications are gathered.

Fortification of polysaccharide-based packaging films and coatings with essential oils: A review of their preparation and use in meat preservation

As the demand for botanical food additives and eco-friendly food packaging materials grows, the use of essential oils, edible biodegradable films and coatings are becoming more popular in packaging. In this review, we discussed the recent research trends in the use of natural essential oils, as well as polysaccharide-based coatings and films: from the composition of the substrates to preparing formulations for the production of film-forming technologies. Our review emphasized the functional properties of polysaccharide-based edible films that contain plant essential oils. The interactions between essential oils and other ingredients in edible films and coatings including polysaccharides, lipids, and proteins were discussed along with effects on film physical properties, essential oil release, their active role in meat preservation. We presented the opportunities and challenges related to edible films and coatings including essential oils to increase their industrial value and inform the development of edible biodegradable packaging, bio-based functional materials, and innovative food preservation technologies.

Silver contamination and its toxicity and risk management in terrestrial and aquatic ecosystems

Silver (Ag), a naturally occurring, rare and precious metal, is found in major minerals such as cerargyrite (AgCl), pyrargyrite (Ag₃SbS₃), proustite (Ag₃AsS₃), and stephanite (Ag₅SbS₄). From these minerals, Ag is released into soil and water through the weathering of rocks and mining activities. Silver also enters the environment by manufacturing and using Ag compounds in electroplating and photography, catalysts, medical devices, and batteries. With >400 t of Ag NPs produced yearly, Ag NPs have become a rapidly growing source of anthropogenic Ag input in the environment. In soils and natural waters, most Ag is sorbed to soil particles and sediments and precipitated as oxides, carbonates, sulphides, chlorides and hydroxides. Silver and its compounds are toxic, and humans and other animals are exposed to Ag through inhalation of air and the consumption of Ag-contaminated food and drinking water. Remediation of Ag-contaminated soil and water sources can be achieved through immobilization and mobilization processes. Immobilization of Ag in soil and groundwater reduces the bioavailability and mobility of Ag, while mobilization of Ag in the soil can facilitate its removal. This review provides an overview of the current understanding of the sources, geochemistry, health hazards, remediation practices and regulatory mandates of Ag contamination in complex environmental settings, including soil and aquatic ecosystems. Knowledge gaps and future research priorities in the sustainable management of Ag contamination in these settings are also discussed.

Food packaging composite film based on chitosan, natural kaolinite clay, and Ficus. carica leaves extract for fresh-cut apple slices preservation

The problem of environmental plastic contamination is one of the most serious issues facing our world today. The majority of the packaging materials used to preserve food are made of plastic which is considered an environmental issue. Natural kaolinite clay (KC) and Ficus leaf extract (FLE) were combined with chitosan in this work to create a novel antioxidant and biodegradable food packaging film. Chitosan/KC/FLE film was compared to chitosan film, Chitosan/KC, and Chitosan/FLE films in terms of structural, physical, and functional aspects. The addition of FLE and/or KC significantly improved the light and moisture barrier characteristics, mechanical properties, and antioxidant capabilities of chitosan film. Moreover, KC addition had a remarkable impact on the water vapor permeability and the biodegradability of the chitosan film. Because of the synergistic action of FLE and KC, the Chitosan/KC/FLE film delivered strong barrier and antioxidant capabilities. Furthermore, Chitosan/KC/FLE film was tested as packaging material on fresh-cut apple slices and demonstrated good food preservation regarding the weight loss, browning index, and total phenolic content of the fruit. According to our findings, Chitosan/KC/FLE film might be employed as a possible food packaging material in the food industry.

Application of cellulose- and chitosan-based edible coatings for quality and safety of deep-fried foods

Excessive oil uptake and formation of carcinogens, such as acrylamide (AA), heterocyclic amines (HCAs), and polycyclic aromatic hydrocarbons (PAHs), during deep-frying are a potential threat for food quality and safety. Cellulose- and chitosan-based edible coatings have been widely applied to deep-fried foods for reduction of oil uptake because of their barrier property to limit oil ingress, and their apparent inhibition of AA formation. Cellulose- and chitosan-based edible coatings have low negative impacts on sensory attributes of fried foods and are low cost, nontoxic, and nonallergenic. They also show great potential for reducing HCAs and PAHs in fried foods. The incorporation of nanoparticles improves mechanical and barrier properties of cellulose and chitosan coatings, which may also contribute to reducing carcinogens derived from deep-frying. Considering the potential for positive health outcomes, cellulose- and chitosan-based edible coatings could be a valuable method for the food industry to improve the quality and safety of deep-fried foods.

Pseudomonas fragi biofilm on stainless steel (at low temperatures) affects the survival of Campylobacter jejuni and Listeria monocytogenes and their control by a polymer molybdenum oxide nanocomposite coating

Pseudomonas spp. are widely distributed bacteria on surfaces in the food production and processing environment, where they form extracellular polymeric substance rich biofilms that interact with other bacteria. In this study, the influence of biofilm of Pseudomonas fragi ATCC 4973 on Listeria monocytogenes ATCC 19115 and Campylobacter jejuni NCTC 11168 was investigated at 5 °C and 15 °C on stainless steel in broth and food homogenates (fish or chicken meat). Stainless steel was then coated with PVDF-HFP/PVP/MoO₃ nanocomposite and examined for surface changes (scanning electron microscope, static contact angle, Vickers hardness and elastic modulus). The effect of the prepared nanocomposite coating on P. fragi and on L. monocytogenes and C. jejuni was evaluated in mono- and co-culture. P. fragi produced more biofilm at 15 °C than at 5 °C, especially when food homogenates were used as growth media. Co-cultivation with pathogens did not affect biofilm production by P. fragi, but significant changes were observed in L. monocytogenes and C. jejuni, resulting in a decrease and increase, respectively, in the determined number of culturable biofilm cells. The first change was probably due to competition for the surface, and the second to the oxygen gradient. Stainless steel was then coated with a PVDF-HFP/PVP/MoO₃ nanocomposite, which was characterised by lower roughness and higher wettability, but lower hardness compared to uncoated stainless steel. The prepared nanocoating showed bactericidal activity when tested in phosphate buffered saline. When used in food homogenates, a reduction of over 95 % in bacterial counts was observed. An abundant biofilm of P. fragi proved protective to L. monocytogenes and C. jejuni against the functionalised nanocomposite surface when tested in food homogenates. The control of spoilage Pseudomonas spp., which are common in the food production and processing environment, is important for reducing the contamination of food with spoilage bacteria and with pathogens such as L. monocytogenes and C. jejuni, which may be present in the same environment. The PVDF-HFP/PVP/MoO₃ nanocomposite showed good potential for use as a coating for food contact surfaces, but possible migration of nanoparticles from the nanocomposite coating to food should be evaluated before its commercial use.

Recent advances of antibacterial starch-based materials

Starch has attracted a lot of attention because it is biodegradable, renewable, nontoxic and low cost. By adding antibacterial substances to starch, starch-based materials have antibacterial properties. The composite with other materials can improve the comprehensive performance of starch-based materials, thus broadening the application field of the material. In this paper, we focus on antibacterial starch-based materials and review their preparation and applications. It was found that antibacterial starch-based materials were most widely used in packaging, followed by medicine, and the research on smart starch-based materials was relatively less. This review may provide some reference value for subsequent studies of starch-based materials.

Green synthesis of nanostructures from rice straw food waste to improve the antimicrobial efficiency: New insight

Applications for nanotechnology, which is constantly gaining prominence, have been found in a variety of industrial applications. Due to the multiple benefits associated with it, including an eco-friendly, pollution-free, cost-effective, and non-toxic synthesis method, the green way to synthesize nanostructures utilizing waste biomasses has become one of the key focuses of the current researches globally. Additionally, lignocellulasic biomass (LCB), which is a waste of the food crops, can be used as one of the potential substrates for the synthesis of a variety of nanostructures. Among different types of LCB, rice straw is a potential food waste biomass and can be efficiently employed during the synthesis of different types of nanostructures for a range of technological applications. Here, diverse phenolic compounds found in rice straw as well as reducing sugars can be used as natural reducing and capping agents to prepare a range of nanostructures. Based on the aforementioned facts, the objective of this review is to investigate the viability of using rice straw to produce nanostructured materials using rice straw as a renewable biosource following an environmentally friendly method. Additionally, it is noted that various organic compounds present on the surface of nanostructures produced using rice straw extract/hydrolyzate through a green approach may be more successful in terms of antibacterial efficacy, which might be of considerable interest for a variety of biomedical applications. Based on the possibility of enhancing the antimicrobial activity of developed nanostructures, the review also provides overview on the feasibility, characteristics, and availability of using rice straw extract in the synthesis of nanostructures. Additionally, the constraints of the present and potential futures of the green synthesis methods using rice straw wastes have been explored.