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Metallic-based micro and nanocomposites in food contact materials and active food packaging *
... The major challenges faced in food processing include surface dehydration, oxidation, contamination via processing environment as well as processing equipment like cutting boards, knives, working surfaces, etc. These factors put forth a need for the robust packaging system which not only plays a primary role of wrapping and transportation but also helps in extending the usable life and ensuring traceability of the products (Duncan, 2011;Llorens et al., 2012;Luo et al., 2021;Weiskopf et al., 2020). With these points in consideration, the application of nanotechnology in the food industry is slowly but steadily attracting research interest. ...
... The commonly used metal oxide nanoparticles in food packaging are TiO2, ZnO, Al2O3 and silica while common metals used include copper and silver. They have a potential to perform multiple functions including photocatalysis, antimicrobial actions, ethylene scavenging, imparting greater mechanical strength and barrier properties (Bumbudsanpharoke et al., 2015;Llorens et al., 2012). In this review, we have reviewed these materials. ...
... Therefore, NPs are being actively used in developing advanced intelligent packaging materials. Integrating NPs into polymeric matrix endows numerous benefits such as it makes packing composite much stronger, lighter and less permeable (Llorens et al., 2012;Videira-Quintela et al., 2021). Further, NPs having inherent antimicrobial activities if incorporated into the polymer helps in preserving food by harmful and spoilage bacteria, fungi and viruses and hence contribute to extend shelf life of food. ...
Packaging is an important feature of our everyday life and it has a vital role to play in food industry. A lot of work is being done for diversifying the role of packaging including use of packaging for increasing the storage time of food items. In this review, we have discussed the role of commonly used metals and metal oxide nanoparticles based antimicrobial agents as a component of packaging material. Though “nano” is a magic word used these days, in this article the potential health hazards on the probable leaching of packaging nanomaterial into food have been discussed. Besides, the safety regulations of various economies have also been covered.
... In some reviews, the use of zeolites has been discussed in polymeric membranes for applications in water purification, catalysis, and gas separation; nevertheless, specific outcomes can also be helpful in understanding the behavior of zeolites in packaging films [87][88][89]. Furthermore, overviews on innovative (including active and nanostructured) additives for conventional and biodegradable polymeric packaging films were presented in other papers, although without providing specific insights on zeolites, cited among other additives [90][91][92][93]. Finally, other reviews focused exclusively on zeolite additives, particularly for packaging applications, but either they are outdated and do not include recent trends in biodegradable polymers or they discuss zeolites as active additives without a detailed study of mechanical, barrier, and thermal properties as well [94][95][96]. ...
... additives for conventional and biodegradable polymeric packaging films were presented in other papers, although without providing specific insights on zeolites, cited among other additives [90][91][92][93]. Finally, other reviews focused exclusively on zeolite additives, particularly for packaging applications, but either they are outdated and do not include recent trends in biodegradable polymers or they discuss zeolites as active additives without a detailed study of mechanical, barrier, and thermal properties as well [94][95][96]. ...
Zeolites are interesting inorganic additives that could be employed for plastic packaging applications. Polyethylene (PE) and polypropylene (PP) are intensively used for packaging as they provide great performance at low cost, even though they have poor environmental sustainability and may be more valorized. Biodegradable polymers may therefore represent a more eco-friendly alternative, but still, they have limited applications due to their generally inferior properties. Therefore, this review focuses on the use of zeolites as additives for flexible packaging applications to mainly improve the mechanical and barrier properties of PE, PP, and some biodegradable polymers, possibly with antimicrobial and scavenging activities, by exploiting zeolites’ cation exchange ability and adsorption properties. Film preparation and characterization have been investigated. The obtained enhancements regard generally higher gas barriers, elastic moduli, and strengths, along with thermal stability. Elongation at break decreased for all PE composites and tended to increase for other matrices. The use of zeolites as additives for polymer films is promising (mainly for biodegradable polymers); still, it requires overcoming some limiting drawbacks associated with the additive concentration and dispersion mainly due to matrix–additive incompatibility.
... This is perhaps the most common application of nanotechnology in food and food-related industries. [15] A number of nanocomposites, polymers containing nanoparticles, are used by the food industry for food packaging and food contact materials [16]. The use of ZnO and MgO nanoparticles for food packaging has been reported. ...
TA nanoparticle is a small particle whose size ranges between 1 to 100 nanometres at least in one dimension. Undetectable by the human eye, nanoparticles can exhibit significantly different physical and chemical properties compared to their larger material counterparts. This is due to a very large surface area to volume ratio when compared to bulk material. When the particle size goes to nanometer range quantum mechanical effects such as quantum confinement dominate the material properties. This feature enables nanoparticles to possess unexpected optical, physical and chemical properties. Due to these unexpected properties, nanoparticles find enormous applications in various fields such as medicine, agriculture, food, energy storage, electronics, pharmaceuticals etc. In this article we concentrate on applications of nanoparticles in food industry.
... Responsive active packaging could be any packaging that generates a therapeutic or informative response in response to a particular trigger or alteration in the external environment, the food product, or the food packaging headspace (Brockgreitens & Abbas, 2016;Vilela et al., 2018). Responsive active packaging offered numerous substantial benefits compared to conventional passive packaging (Llorens et al., 2012). The following aspects are the primary manifestation of these advantages: The shelf life of food can be extended more efficiently and actively by responsive active packaging, which can dynamically interact with the environmental conditions inside and outside the food package. ...
Cereals are the cornerstone of human nutrition, providing a staple source of carbohydrates, proteins, and essential nutrients that are vital for the sustenance of global populations. However, microbial contamination and lipid oxidation of cereal products have caused great losses to human beings, and even threaten human health. The food safety and shelf life of cereal products were related to the field of food packaging. Unlike traditional packaging, which primarily serves as a protective barrier, active packaging could interact with the environment inside the package to extend the shelf life of cereal products. This paper reviewed the classification of responsive active packaging, including temperature, light, pH, humidity, oxygen, and enzyme response, and briefly analyzed some of the mechanisms. And then, the application and prospects of responsive active packaging in cereals and their products were specifically discussed, in order to provide some feasible schemes for improving the safety and quality of cereal products.
Graphical Abstract
... 1,2 In recent years, the importance of antimicrobial and sustainable packaging systems has increased tremendously due to their high food preservation, environmentally friendly, and nontoxic properties. 1,[3][4][5][6][7][8] Polymer nanocomposites are one of the most researched antimicrobial food packaging materials, combined with the importance of both flexibility and antimicrobial properties. [9][10][11][12][13] Such antimicrobial polymer composites as food packaging systems prohibit microbial growth and delay the spoilage hours of food, thereby effortlessly replacing the traditional packaging system. ...
This paper introduces an innovative strategy for preparing sustainable food packaging composite material comprising water‐soluble PVA and varied content of antimicrobial ZnO paper ash (0, 1, 5, and 10) wt.%. Following the sustainable approach, the ZnO nanoparticles are synthesized using waste papers in a simple and efficient process. Among the synthesized composites, the PVA/ZnO paper ash (5 wt.%) composite achieved significant antimicrobial efficacy, with inhibition zones of 40 ± 0.01 mm for gram‐positive and 37 ± 0.02 mm for gram‐negative bacteria. Such an antimicrobial performance surpasses many conventional PVA/ZnO composites. Additionally, the PVA/ZnO paper ash (5 wt.%) composite biodegraded within 40 days and showed excellent renewable properties. The food packaging application of fruit and vegetables was evaluated by monitoring the variation in physical appearance, weight loss rate, and pH conditions. Also, the antifungal test was assessed through the packaging of bread. The packaging tests revealed that while polyethylene (PE) films allowed quick spoilage due to pathogens, the composite packets maintained food freshness, underscoring its superior antimicrobial properties. Therefore, its improved antimicrobial and food preservation properties indicate that the PVA/ZnO paper ash composite is a promising and practical solution for sustainable and antimicrobial food packaging applications.
Highlights
Novel PVA/ZnO paper ash composite.
Easy, ecofriendly synthesis of the antimicrobial film by using waste paper as a functional material.
High antimicrobial property of PVA/ZnO paper ash.
PVA/ZnO paper ash composite as an effective food packaging system.
Superior antifungal activity of PVA/ZnO paper ash composite.
... CEO is a natural oil with strong antimicrobial properties against foodborne pathogens and fungi. However, CEO tends to decompose at relatively low temperatures (< 60°C), generating benzaldehyde [194,195]. Consequently, to enhance the antibacterial properties of packaging materials with CEO, it is important to avoid exposing it to high temperatures. Cinnamaldehydes have been demonstrated to be the primary active ingredient in CEO. ...
Food packaging plays a crucial role in preserving food and extending shelf life. Traditionally, packaging materials have been derived from petroleum-based polymers. However, growing concerns regarding the environmental impact and health risks of synthetic materials have underscored the need for sustainable, biodegradable and renewable alternatives. Edible films, made from naturally sourced biopolymers such as polysaccharides and proteins, offer a promising solution to replace synthetic plastics. Extensive research has been conducted to explore the full potential of edible films, particularly focusing on their integration with bioactive polymers and essential oils as antimicrobial agents. This review synthesizes the findings of previous studies, examining the properties, applications and benefits of these bioactive films in food packaging. It further discusses the antibacterial and antifungal properties of essential oils, their role in enhancing the functionality of edible films and the future challenges and prospects of this emerging field. This article aims to provide valuable insights for researchers working on the development of sustainable food packaging solutions.
... Silver, silver ions and silver compounds were analyzed for antibacterial and antiviral effects. Using bioactive substances such as chitosan, lysozyme and nanosilver might extend the spectrum of their activity to other food species of bacteria (Liorens et al., 2012). This study aimed to determine the antimicrobial ability of chitosan, lysozyme and nanosilver to serve as a scientific basis for developing a beef preservation process using chitosan, lysozyme and nanosilver. ...
Beef contains many nutrients such as water, protein, lipids, vitamins, and minerals and is especially rich in irreplaceable amino acids. Currently, in Vietnam as well as around the world, beef is mainly preserved cold and frozen. This study aimed to determine the antimicrobial ability of chitosan, lysozyme and nanosilver to serve as a scientific basis for developing a beef preservation process when using chitosan, lysozyme and nanosilver. The increasing concentration of chitosan in the membrane with the addition of cellulose also greatly reduces the growth of Escherichia coli. Lysozyme which is a component of the hydrosol protective layer can be effective against Gram-negative bacteria when the outer membrane of bacteria is interrupted or is not covered with chitosan. The total number of bacteria in the reference sample of beef after 9 days of storage was 8 log CFU/ g, but the same sample sprayed with variant no. 9 biocomposite hydrosol resulted in the inhibition of microorganisms about 2.5 log CFU/g. When 1% of chitosan was added to the beef patties and stored at 4°C for 10 days, a 1 to 2-log CFU/g reduction of the bacterial count was observed.
... Metal nanoparticles and metal oxide nanoparticles have different properties because the metallic material is always separated from nanoscale particles. [1] Metal oxide nanoparticles and metal nanoparticles are exercised in various ways, for instance, reactant, [2] medication delivery, [3] augmenting amazing agents, [4] smart food packaging materials, [5] elements indicating nano-biosensor development, [6] transposition system, and nanoelectronic elements. [7] Metal nanoparticles are also used in the identification of microorganisms and pestilence and extended to application in germicides, antibiotics, and disinfectants. ...
To attain the required therapeutic concentration of the drug at the target site with minimal exposure to normal cells, a targeted strategy is essential in cancer treatment. Because of its various advantages, a ligand-tagged bioactive medication is the ideal option. The use of natural therapeutic substances payload in the metallic nanoparticles conjugated with ligands is highlighted in the review. The most intriguing delivery system for these naturally occurring oncological medications is a nanoparticle-based drug delivery system because of its selectivity and specificity. Making a nanoparticle with metals enhances these benefits because of the synergistic profile in potential applications.
... Furthermore, food packaging uses silica and metal oxide nanoparticles like zinc oxide, aluminum oxide, and titanium dioxide. In addition to being employed as photocatalysts with antibacterial and ethylene-scavenging capabilities, these nanoparticles can enhance the nanocomposite's tensile strength, gas barrier, and UV barrier qualities (Bumbudsanpharoke and Ko, 2015;Llorens et al, 2012). ...
Nanotechnology has certainly become a phenomenon that is of great significance in many regions such as the pharmaceutical, cosmetic and in particular the food sector, over the years. This is because nanotechnology overlaps with pharmaceutical sciences which involve the structural modification of materials to the nano level, increasing the dissolution rate, stability, and functionality of a variety of food safety and quality applications. The novel food supply frameworks enable firms within the food sector to emerge sustainability focused innovations, which tackle safety and nutrition deficiencies within the food industry. Narrowing down on the supply chain, this review seeks to highlight nanotechnology applications across food supply chains, stressing the importance of advancements in bioavailability, nutrition, and safety. In aid of nutrient delivery, overcoming shelf life and packaging issues – development in nanoencapsulation technology and new packaging materials have enhanced mechanical properties, antibacterial properties. Moreover, nanodevice-based smart packaging is considered as valuable tools for real-time monitoring of food safety and quality. Despite these benefits, degenerative concerns about nanoparticles health risks underscore the importance of sound regulatory approaches. While nanotechnology shows considerable potential for enhancing food sustainability and quality, the study ultimately finds that comprehensive regulation and increased public awareness of potential risks are necessary first steps. Continued research and global collaboration may be vital to really unlock the potential of nanotechnology in food systems while safeguarding public health.
... ZnO-NPs have been employed as functional coatings/films in various packaged meat items to reduce the antibacterial activity of S. aureus and Pseudomonas aeruginosa. ZnO-NPs are also cost effective, low in toxicity and have additional UVblocking properties (Llorens et al., 2012) (Arakha et al., 2015) which tend to make them a desirable option. ...
... But, with the emergence of engineered nanomaterials in food packaging, active and intelligent attributes have been added. The major advantage of using engineered nanoparticles to develop packaging materials is to enhance their mechanical, thermal, and antimicrobial properties [88]. Further, in vivo human toxicity studies have also shown that engineered nanoparticles were clinically safe if taken orally [89]. ...
Nanomaterials play a pivotal role in food preservation and its safety, offering ingenious solutions for sustainable food packaging. Nanomaterials enable the creation of packaging materials having unique functional properties. It not only extends the shelf life of the foods by releasing preservatives but also enhances food safety by preventing microbial contamination or food spoilage. In this review, we aim to provide an overview of the various applications of nanotechnology in food packaging, highlighting its key advantages. We also delve into the safety considerations and regulatory issues involved in developing nanotechnology-based food packaging materials. Additionally, advancements in the field of nanotechnology-based packaging have the potential to create safer, more sustainable, and high-quality packaging with greater functionality that delivers essential benefits to manufacturers and consumers.
... Among these developments, copper based nanoparticles e.g. Cu NPs or CuO NPs, have become widely used due to its antimicrobial activity 1-4 and prospective applications in the biomedical field, including drug delivery 5,6 and diagnostics 7 , as well as in agricultural and other commercial applications [8][9][10][11] . However, the widespread use of nanoparticles (NPs) has raised concerns about their potential impact on the environment 12-15 , particularly in the aquatic environment, where waste ultimately accumulates 16 . ...
The same elements can yield disparate nanoproducts that may elicit different harmful effects in cells and organisms. This study aimed to compare the effects of copper (Cu NPs) and copper oxide (CuO NPs) nanoparticles and Cu²⁺ (from CuSO4) on the physico-biochemical variables of rainbow trout spermatozoa. The cell death assay, along with the activation of caspases 8 and 9, the level of reactive oxygen species (ROS), and the percentage of cells exhibiting a high mitochondrial membrane potential (MMP) were quantified over 24-hour incubation. Interestingly, during exposure, all copper products induced cell apoptosis. However, Cu NPs had a stronger effect than CuO NPs, while the impact of the Cu in ionic form was found to be between the other two compounds. The extrinsic and intrinsic apoptotic pathways were activated, as evidenced by the activation of caspases 8 and 9. Initially, caspase activation increased without a corresponding decrease in MMPs but prolonged exposure resulted in a significant decrease in MMP levels. In all treated cells, the ROS levels increased over time. Further studies are needed to confirm the lower CuO NPs’ toxicity compared to Cu NPs because their effect on cells also depends on many other parameters such as size or shape.
... For example, the mechanical and barrier properties, and thermal stabilities of collagen fiber films were improved by the addition of HAP . Moreover, HAP is known to successfully encapsulate various antimicrobial substances within its structure, forming active food packaging systems (Llorens et al., 2012). ...
An active chitosan (CS) film containing a nano-hydroxyapatite–tea polyphenol (HAP-TP) complex was designed and prepared. The effects of HAP-TP loading on the structural and physicochemical properties of the CS-based film were evaluated. The mechanical and thermal properties of the film were significantly improved by the resulting intermolecular interactions and formation of hydrogen bonds between HAP-TP and CS, which reduced the water vapor and oxygen permeabilities of the film by 29.78 and 35.59 %, respectively. The CS-HAP-TP film exhibited excellent slow-release behavior and antioxidant activity, with a cumulative release rate at 700 h 6.79 % lower than that of CS-TP films. The CS-HAP-TP film significantly inhibited the deterioration of semi-dried golden pompano, and thus helped to retain the taste of umami and sweet amino acids in fish samples, while reducing off-flavor generation. The film therefore shows considerable potential as an active packaging material for the preservation of semi-dried fish products.
... Nanomaterials exhibit remarkable strength, barrier capabilities, and interactions that extend beyond those found in conventional packaging materials [3,4]. Through the fusion of food science, material engineering, and nanotechnology, this paper embarks on a comprehensive exploration of the study of food locking and packaging by nanomaterials [5,6]. By elucidating the intricate interplay between nanomaterials and food preservation, we strive to unlock the full potential of these innovations and their impact on the global food landscape. ...
Food preservation and packaging are crucial for maintaining the quality, safety, and shelf life of consumable products. In recent years, the integration of nanomaterials into food packaging has emerged as a promising approach to address challenges associated with food spoilage, contamination, and quality degradation. This study delves into the innovative application of nanomaterials in food packaging, exploring their potential to revolutionize the food industry. Through a comprehensive analysis of various nanomaterials, their properties, and their impact on food preservation, this study aims to shed light on the transformative role of nanotechnology in enhancing food locking and packaging. By examining the barriers, antimicrobial effects, and nano-enabled smart packaging solutions, this research provides insights into the mechanisms that underpin the success of nanomaterials in maintaining food freshness and extending shelf life. Furthermore, this paper discusses safety considerations and regulatory frameworks surrounding the utilization of nanomaterials in food packaging, ensuring that the benefits of these innovations are realized without compromising consumer health.
... Nonthermal processing using UV, ozone, other emerging technologies assure safety while preserving nutrition [136]. Active packaging solutions dynamically regulate internal atmosphere for freshness retention [137]. Radio frequency identification (RFID) sensors and blockchain platforms enhance supply chain transparency from farm to consumers [138,139]. ...
Horticulture plays a vital role in global food and nutritional security. This review covers recent advances and emerging trends across various facets of horticultural production and management. Key focus areas include protected cultivation, precision agriculture, new cultivar development, innovations in propagation and breeding, micro irrigation systems, nanotechnology applications, and integrated pest management. The potential of advanced technologies like automation, robotics, artificial intelligence, and genetics in transforming horticulture is discussed. Challenges for sustainable intensification of horticultural systems are examined. The review highlights how cutting-edge sciences, digital integration, and ecological approaches will shape the future of horticulture with more productive, efficient, and climate-resilient production.
... Nonthermal processing using UV, ozone, other emerging technologies assure safety while preserving nutrition [136]. Active packaging solutions dynamically regulate internal atmosphere for freshness retention [137]. Radio frequency identification (RFID) sensors and blockchain platforms enhance supply chain transparency from farm to consumers [138,139]. ...
Horticulture plays a vital role in global food and nutritional security. This review covers recent advances and emerging trends across various facets of horticultural production and management. Key focus areas include protected cultivation, precision agriculture, new cultivar development, innovations in propagation and breeding, micro irrigation systems, nanotechnology applications, and integrated pest management. The potential of advanced technologies like automation, robotics, artificial intelligence, and genetics in transforming horticulture is discussed. Challenges for sustainable intensification of horticultural systems are examined. The review highlights how cutting-edge sciences, digital integration, and ecological approaches will shape the future of horticulture with more productive, efficient, and climate-resilient production.
... Solutions that can kill microbes or make it harder for them to adhere to surfaces have been studied extensively to prevent germs spread and the formation of biofilms. These surface-bound active antimicrobials and biocidal coatings are produced using chemically altered substances, nanomaterials, and/or micro-and nanostructuring (Llorens et al. 2012), or passive pathogen-repellent surface (Imani et al. 2019). ...
... These metal oxide nanoparticles also exhibit antimicrobial properties, making them efficient against bacteria, fungus, and viruses. Due to its lower reduction potential, copper nanomaterial oxidizes fast, creating copper ions with high mobility to interact with the cytoplasmic membrane (Conte et al. 2013;Llorens et al. 2012). These nanoparticles are also employed as water disinfectants, semiconductors, solar cells, and other uses in pharmaceuticals, chemical-engineering, and food industries. ...
Innovations in the development of nanotechnology have led to new opportunities in the food processing and packaging sectors. Engineered nanomaterials provide substantial advantages, such as: improving the barrier and physicomechanical characteristics of packaging materials; provide cost-effective packaging materials with better functionality, shelf-life, portability, and biodegradability. Nanoclay, silver, zinc oxide and titanium-based nanoparticles are often used in the packaging applications. In the synthesis of nanomaterials, bottom-up and top-down techniques are applied. Nanotechnology-based active and smart packaging materials release or absorb components into/from the food, thus providing information on the status of the food inside the package. With the introduction of nanotechnology in food packaging, a gap in understanding of nanoparticle behavior in food and environmental systems has arisen. The migration of nanoparticles from packaging materials into food, and the health hazards linked with it, are also major concerns. Hence, it is imperative to understand the toxicity, bioaccumulation, and long-term implications of engineered nanomaterials to the environment and public health. Common techniques for the assessment of engineered nanomaterials include: spectroscopy, microscopy, light scattering, chromatography, and electrophoretic techniques. The existing assessment techniques are challenged by particle size heterogeneity and aggregation, as well as nanoparticles (NPs) bio-uptake by different species. Research need be strengthened to develop standardized approaches for assessing nanoparticles in the complex media. The state-of-the-art in the synthesis of nanomaterials, safety issues and assessment approaches has been presented in this chapter.
... Metal and metal oxide NPs have been increasingly studied as antimicrobial agents due to their unique properties that can provide advantages over traditional antibiotics. Some of the benefits of MNPs include broad-spectrum activity, resistant to resistance development (different mode of action than traditional antibiotics), biocompatibility, environmentally friendly and cost-effective (Llorens et al., 2012a). However, the size and shape of MNPs hold significant importance concerning safety considerations and their applicability in the food industry (Moreno et al., 2019). ...
Eliminating microbial growth and preventing food degradation from excess moisture is an important technological advance in packaging. This article describes the development of a novel antimicrobial superabsorbent pad for food packaging, which uses carboxy methyl cellulose (CMC) as a polymer matrix and biogenic vaterite calcium carbonate microspheres loaded with AgNPs (CaCO3–Ag). The spherical vaterite CaCO3–Ag hybrid was obtained by precipitating CaCO3 from discarded eggshells in silver colloid. The vaterite CaCO3–Ag microspheres were incorporated into the CMC matrix, which underwent physical cross-linking initially and was further chemically cross-linked during film surface treatment. The resulting three-layer film exhibits improved hardness and modulus of 0.09 and 3.30 GPa, respectively. The crystallinity was enhanced, and water absorption capacity attained was 13.87 times of film weight. The antimicrobial activity with inhibition zones of 6 and 14 mm against Escherichia coli and minced pork bacteria, makes it suitable for use as an antimicrobial superabsorbent pad in meat packaging applications.
Food waste and packaging disposal have become a problem throughout the ecosphere because more than 90% of wasted food is discarded into landfills. Paper, wood fiber and cellulose nanoparticles are all biologically based materials that have been found in response to the growing demand for environmentally friendly packing. These tend to be more environmentally friendly with more extraordinary shelf life. There are still requirements to be effective solutions applied, however to augment performance in packing. Recent novelties have led to food safety-improving films of nanoparticles and bio-based bioplastics. Active packaging solutions comprise antimicrobial agents and antioxidant-rich inorganic nanoparticles that improve the oxygen and moisture barrier properties and prevent microbial contamination. Due to their capability to extend shelf life without affecting food safety, antimicrobial bio-nanocomposites are acquiring more popularity. Since it delivers long-term costs and energy savings and decreases reliance on fossil fuels, the economic viability of bio-based packaging is a critical consideration.
The field of nanotechnology has brought about a remarkable transformation in the food industry, introducing new technological advancements that have the potential to revolutionize the Agrifood sector. Nanoparticles, in particular, have become a viable resource for enhancing global agricultural production, enhancing nutritional value, and ensuring food safety and quality. One of the many varieties of nanoparticles is Silver nanoparticles (AgNPs),, which are widely utilized for their potent antibacterial and bactericidal properties and their wide range of antibacterial effects. The nanoparticles are typically produced by utilising three distinct methods, including chemical, physical, and green synthesis (biological techniques). The green synthesis strategy is the most commonly used, since it is affordable and environmentally beneficial. AgNPs have a wide range of uses in the food and agricultural industries, including Nanofertilizers, Plant Growth Aid, Pesticide Remediation, Plant Disease Management, Crop Protection, Food Processing, Food Packaging, Safety Enhancement, Quality Monitoring of food, Nano-sized Additives, Nutraceuticals, etc. Nanoparticles continue to drive innovation in the food and agricultural industry, from innovative packaging solutions to advanced sensing technologies and novel processing techniques. Nanotechnology has become an indispensable tool for addressing existing difficulties associated with packaging materials, positively impacting the quality, safety, and security of foods, and being advantageous to producers and consumers.
The field of nanotechnology has brought about a remarkable transformation in the food industry,
introducing new technological advancements that have the potential to revolutionize the Agrifood
sector. Nanoparticles, in particular, have become a viable resource for enhancing global agricultural
production, enhancing nutritional value, and ensuring food safety and quality. One of the many
varieties of nanoparticles is Silver nanoparticles (AgNPs),, which are widely utilized for their potent anti
bacterial and bactericidal properties and their wide range of antibacterial effects. The nanoparticles
are typically produced by utilising three distinct methods, including chemical, physical, and green
synthesis (biological techniques). The green synthesis strategy is the most commonly used, since it is
affordable and environmentally beneficial. AgNPs have a wide range of uses in the food and agricultural
industries, including Nanofertilizers, Plant Growth Aid, Pesticide Remediation, Plant Disease
Management, Crop Protection, Food Processing, Food Packaging, Safety Enhancement, Quality
Monitoring of food, Nano-sized Additives, Nutraceuticals, etc. Nanoparticles continue to drive
innovation in the food and agricultural industry, from innovative packaging solutions to advanced
sensing technologies and novel processing techniques. Nanotechnology has become an indispensable
tool for addressing existing difficulties associated with packaging materials, positively impacting the
quality, safety, and security of foods, and being advantageous to producers and consumers.
Keywords: Antimicrobial, Food industry, Nano fertilizers, Nutraceuticals, Pesticide remediation
Long-lasting food freshness in packaging materials is a highly desirable quality. Incorporating nanoscale fillers into the polymer matrix has the latent to mend the functional properties of the packaging material and may address certain problems. The melting point and glass transition temperatures of polymers containing nanocomposites are altered, along with their surface wettability, hydrophobicity, and improved barrier. Additionally, inorganic nanoparticles may assist to slow down the proliferation of germs within the packing. By using nano-sized components in biopolymer-based packaging materials, waste spawned during the packing procedure might be minimized. In food packaging, inorganic nanoparticles such as titanium oxide, zinc oxide, copper oxide, silver, and gold are most commonly used. These packaging materials may improve the physicochemical and functional characteristics of food systems. Researchers are investigating a number of applications for metals and metal oxide nanoparticles in food films in an attempt to enhance food packaging films and may prolong the shelf life of food itens.
This chapter explores the growing field of emerging nonthermal technologies and biotechnologies focusing on how they can be used in combination with antimicrobial packaging to extend the shelf life of beverages while preserving their nutritional and sensory quality. High pressure processing (HPP), Ultra-high pressure homogenization (UHPH), pulsed electric fields (PEF), pulsed light (PL), and cold plasma (CP) are some of the key technologies explored. The mechanism of antimicrobial action of each technology, the operational parameters and their impact on packaging materials are discussed. Moreover, the relevance of performing compatibility tests between the processing technology and the packaging material to assess the potential migration of certain compounds into the beverage is emphasized. Natural antimicrobials, such as essential oils, bacteriocins and organic acids, are also presented as a safe and effective alternative to ensure the microbiological stability of beverages, as they can be incorporated into packaging materials or used in conjunction with nonthermal technologies to achieve a synergistic effect. Finally, bioprotection is also addressed as a promising and sustainable tool that uses microorganisms such as yeasts and bacteria to control pathogenic and spoilage bacteria, while reducing the need for chemical preservatives. How bioprotective microorganisms such as Lachancea thermotolerans and Metschnikowia pulcherrima can be used to increase shelf life and at the same time improve the overall quality of beverages is detailed.
The food packaging business is rapidly expanding, necessitating careful attention to the problem of sustainability when substituting plastic products with biodegradable packaging. The functional features of biobased packaging, such as mechanical and barrier qualities, are significant challenges. The same package with varying functionality may be created using different nanomaterials as fillers in packaging composites. This chapter focuses on applying bio-nanocomposites in food packaging for active, intelligent, and smart functioning. These Bio-nanocomposites can be made from natural or synthetic polymers with biodegradable characteristics. The development of bio-nanocomposites in food packaging is covered, along with a detailed analysis of several forms of nanomaterials used in food packaging. Bio-nanocomposites are presently employed in food packaging research to build packages with various functions such as oxygen scavenging, time temperature indication, controlled release of nutraceuticals and bioactive substances, antibacterial properties, and sensing capabilities. Because the toxicological impact of using nanoparticles has minimal scientific validity, these biobased nanocomposite packages have limited interaction with food products. As a result, additional experimental work on this intriguing subject is required.
Biomaterials engineering approaches for treating bone defects involve utilizing a combination of potent bioactive molecules to stimulate cell proliferation, fostering a conducive environment and scaffold for the regeneration process. Due to the aging global population, there is an urgent need for research in bone regeneration and wound healing. Hydroxyapatite (HAP) is a major mineral component of bone tissue with high biocompatibility and bioactivity. Agar and carboxymethyl cellulose (CMC) both exhibit the essential characteristics of biomaterials, either separately or in combination. Hence, this present study aimed to prepare HAP nanoparticles loaded Agar/CMC composite film for enhanced bone regenerative applications. The crystal structure, morphology, phase composition, thermal stability, and chemical state of the film composites were characterized using XRD, SEM, TGA, and FTIR. Cytotoxicity evaluation on rat fibroblasts cells indicated over 90% biocompatibility for the film composites. Moreover, in wound healing assays, the nanocomposite film-treated group (98.14 ± 0.15%) exhibited a 35% higher wound closure rate compared to the negative control group (62.08 ± 1.87%). Alizarin Red Staining assay revealed a 20.89 ± 6.9% increase in calcium deposition in treated MC3T3-E1 cells compared to the negative control, affirming their osteogenic potential. These results demonstrate that the developed nanocomposite film is a promising therapeutic platform for effectively addressing complex bone-related ailments.
This chapter investigates the critical aspects of safety and regulatory concerns associated with organic nanomaterials, a burgeoning field with immense potential in various applications ranging from medicine to environmental protection. As these materials find broader usage, understanding their impact on health and the environment becomes paramount. The chapter outlines the current knowledge on the toxicological effects of organic nanomaterials, shedding light on their interaction with biological systems. It also reviews existing regulatory frameworks globally, highlighting the challenges and gaps in adequately addressing the unique properties of nanoscale materials. Furthermore, it discusses the development of standardized methods for risk assessment and the need for harmonized regulations to ensure safety without stifacing innovation. This comprehensive overview aims to guide researchers, policymakers, and industry stakeholders in navigating the complexities of safely integrating organic nanomaterials into societal applications.
In the past few years, rise in the concentrations of inorganic and organic pollutants has become a major concern for environment. Addressing the elimination of these harmful pollutants from the environment is complex and necessitates the utilization of physical, chemical, and biological methods. One approach that shows great promise is the combination of bioremediation and nanotechnology, known as nano-bioremediation. Extensive research has demonstrated the remarkable properties of nanomaterials, including enhanced catalysis, adsorption capabilities, and high reactivity, which have generated significant interest. A notable trend in this field is the use of fungal, bacterial, and algal cultures, as well as their extracts, components, or biomolecules, as catalysts for sustainable nanomaterial synthesis. Understanding the intricate relationship between pollutants, microorganisms, and nanoparticles is important for advancing our knowledge of their interactions. This chapter focuses on the elimination of toxic pollutants by the synergistic effects of nanoparticles and microbial technologies and exploring their applications in different fields. The resulting nanoparticles possess environmentally friendly traits, sensitivity, and biocompatibility making them highly suitable for applications in consumer industries, environmental remediation, and biomedical sciences. Moreover, we emphasize the importance of this innovative nano-bioremediation technique and its contribution to sustainability endeavors. By leveraging the combined potential of nanomaterials and microbial systems, we can pave the way for effective and environmentally friendly solutions to address pollutant remediation.
The preservation of food products using packaging with antimicrobial properties is a major challenge. Using a simple dipping procedure, we propose to functionalize the surface of commercial polypropylene (PP) films with various hybrid components based on biopolymers with silver nanoparticles (AgNPs) that are known for their bactericidal properties. The chosen biopolymers are polysaccharides in solid form such as cellulose nanocrystals (CNC) and chitin nanocrystals (ChiNC), as well as hydrosoluble molecules such as alginate and chitosan for which some OH groups serve as nucleation points for AgNPs. The successful coating was demonstrated via the presence of biopolymers on the PP film surface using electron and fluorescence microscopies. The effective presence of AgNPs on the PP film was then confirmed by atomic absorption spectroscopy measurements. Migration tests performed over 10 days made it possible to track the kinetic release of Ag⁺ in a food simulant. A persistent and increasing release over time was observed, especially for hybrids in solid form (i.e., CNC/AgNP, ChiNC/AgNP), bearing the smaller AgNPs (20 nm). The maximum value of Ag + released was ~0.30 mg Ag/kg, which is significantly lower than the value authorized by international organizations.
The creation of smart packaging, nanosensors, nano pesticides, and nano fertilisers, in particular, has been made possible by the tremendous advancement of nanotechnology. For enhancing safety and quality of food, agricultural development, and environmental sensing, numerous new nanomaterials have been produced. The most prominent developments in nanotechnology are highlighted in this overview, along with the exciting prospects in the agricultural and food industries, as shown by a few recent studies. Nanoparticles, nanofibres, nanoemulsions, and nanocapsules are just a few of the novel instruments that nanobiotechnology provides to alter and improve crop output. A platform for delivering agrochemicals and other macromolecules needed to improve plant development and stress resistance is provided by nanomaterials. The bioavailability, flavour, texture, and consistency of food are all improved by applications of nanotechnologies by altering the element proportions, probable group formation, and surface charge of food nanomaterials. Use of nanotechnology can boost crop yield by increasing the efficiency of agricultural inputs like fertilisers and insecticides that decrease crop loss. Nanomaterials enable site-specific release of agricultural nutrients for crop protection and growth by acting as transporters.
The rapid development of nanotechnology in recent years has impacted a number of elements of food science, including production, packaging, preservation, transportation, functioning, and safety. For example, nanotechnology is more effective than traditional food processing methods with regard to extending the storage life of food items, reducing contaminants, and enhancing product quality. Moreover, nanoparticles may enhance the sensory qualities of food products by introducing innovative structure, color, and appearance. Numerous studies have demonstrated the prospective use of nanoparticles for improving the qualities of packaging and edible coatings owing to their antibacterial activity, higher specific surface area, and high physiochemical resilience. Nanoparticles assist not only in the destruction of pathogens but dangerous fungi and viruses as well. Nano-emulsions and nano-encapsulation of bioactive food components are examples of developing nanotechnology uses in the food industry. The present study focuses on the practical applications of antimicrobial nanoparticles primarily in food packaging and production for a variety of food items, in addition to the advantages and hazards connected with their use.
Packaging is a technology and art that has been developed to enclose and protect a variety of objects for use in trade, storage, and circulation. Creating concepts for active and intelligent packaging has improved the superiority of food products and produced a wealth of new outcomes for postponing the deterioration of packaged food. Unquestionably, one of the best advancements in packaging technology is active packaging. Active packaging, such as modified active packaging (MAP) systems, improves appearance and delays ripening while also extending the shelf life of fresh items, providing a high-quality food product and lowering economic losses. To maintain the freshness of packed food products like fresh fruits, vegetables, dairy, and meat products, there are several different packaging solutions available. By incorporating components like antimicrobial agents, antioxidants, carbon dioxide absorbers, etc. in the built-in packaging systems, such as the packaging films, sachets, or an absorbent pad, that either release or absorb active chemicals into the packaged goods or adjoining environment, aids in extending the stability of packed food products and improves the performance of the packaging. These elements can surround the food, preventing food deterioration and extending the shelf life of the product. This extensive analysis examines the cutting-edge active food packaging technologies that have recently been developed with the aim of preserving or extending the shelf life and quality of food products.
This comprehensive review investigates a variety of creative approaches in the field of sustainable food packaging biomaterials in response to growing environmental concerns and the negative effects of traditional plastic packaging. The study carefully looks at new developments in biomaterials, such as biodegradable polymers, ceramics, composites, and metal alloys, in response to the growing need for environmentally suitable substitutes. It highlights how they might replace conventional plastic packaging and lessen environmental damage. Moreover, the incorporation of nanotechnology into packaging is closely examined due to its crucial function in J o u r n a l P r e-p r o o f improving barrier qualities, introducing antimicrobial properties, and introducing smart packaging features. The investigation includes edible coatings and films made of biodegradable polymers that offer new sensory experiences in addition to prolonging the shelf life of products. The review emphasizes the use of biomaterials derived from food processing and agricultural waste, supporting environmentally responsible methods of producing materials while simultaneously using less resources and waste. As a strong defense against plastic pollution, the report highlights the food industry's increasing use of recyclable and biodegradable packaging, which is in line with the concepts of the circular economy. A movement in consumer tastes and regulatory pressures toward sustainable food packaging is evident in global market patterns. Notwithstanding these encouraging trends, there are still issues to be resolved, including cost-effectiveness, technological constraints, and the scalability of biomaterial production. This thorough analysis concludes by highlighting the critical role biomaterials have played in guiding the food industry toward sustainability and emphasizing the need for ongoing research and development to adequately address environmental issues on a worldwide scale and satisfy the growing demand for environmentally friendly packaging options. Biomaterials show great promise as catalysts for the food industry's transition to a sustainable future.
This research deals with the synthesis of nanosized copper as colloidal solution and its application to cotton fabric. Copper nano colloids were prepared by chemical reduction of copper salt using sodium borohydride as reducing agent in presence of tri-sodium citrate. The size and size distribution of the particles were examined by particle size analyzer and the morphology of the synthesized particles was examined by SEM and AFM techniques. X-ray fluorescence spectroscopy detected the presence of copper in the treated fabric. The results of particle size analysis showed that the average particle size varied from 60 nm to 100 nm. The nano copper treated cotton was subjected to soil burial test for the assessment of its resistance towards microbial attack. SEM images of treated fabric indicate copper nano particles are well dispersed on the surface of the specimens. The treatments of nano copper colloidal solution on cotton not only improve its antimicrobial efficiency but also influenced the tensile strength of the fabric sample positively. The treatment was found to enhance the color depth and fastness properties of direct dyed cotton fabric samples. INTRODUCTION The fundamentals of nanotechnology lie in the fact that properties of substrates dramatically change when their size is reduced to the nanometer range. Moreover, a small amount of nanosize species can interfere with matrix polymer that is usually in similar size range, bringing up the performance of resultant system to an unprecedented level.
A series of titania nanoparticles was successfully synthesized via sol gel method using titanium tetraisopropoxide as a precursor. In this paper, data concerning the effect of pH towards the development of TiO2 nanoparticles is reported. The samples were characterised by x-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). XRD results showed the existence of nanocrystalline anatase phases with crystallite size ranging from 7-14 nm. Surface morphological studies obtain from SEM micrograph showed the particles with rodlike shape are rutile while the spherical shapes are anatase in nature. It was also found the pH of the solution affect the agglomeration of the particles. Results of photocatalytic studies exhibits that titania powder prepared at pH 9 has an excellent photocatalytic activity with degradation 74.7% within 60 minutes.
The effects of a novel nano-ZnO coated PVC film on physicochemical quality and microbiological changes of fresh-cut ‘Fuji’ apple were evaluated. Fruit decay were efficiently reduced in nano-packing samples. The content of ascorbic acid and total phenolic dropped to 0.2 g•kg-1, 1.2 g•kg-1 in nano-packing samples and 0.02 g•kg-1, 0.6 g•kg-1 in control on day 12. In addition, the nano-ZnO coated PVC film not only inhibited the growth of total aerobic psychrophilic microorganisms, the count of which did not exceed 5 log cfu g−1 FW, but also suppressed the increasing of yeast and mould, the maximum growth of which reached only 3.6 log cfu g−1 in the nano-packing but 6 log cfu g−1 in control.
Composite materials of the alumino silicate minerals, kaolinite and halloysite, with silver nanoparticles have been successfully synthesised. This was achieved by a layer-by-layer deposition process in which kaolinite or halloysite was dispersed in successive solutions of the cationic polymeric linker polydiallyldimethylammonium chloride and anionic polymethacrylic acid capped silver nanoparticles. The optical properties of the metallic nanoparticles were retained in the composites and attractively coloured powders were produced. Electron microscopy revealed the silver to be nanospheres, ranging in diameter from 5–40 nm depending on the method of preparation. The chemical and physical characterisation of the resultant composites, particularly the mode of bonding between the nanoparticles and clays, was undertaken through X-ray diffraction, X-ray photoelectron spectroscopy and solid state NMR. The composites showed effective anti-microbial activity against Staphylococcus aureus bacteria.
An artificial nanocomposite medium made by embedding copper nanoparticles covered by copper oxide in a high-pressure polyethylene
matrix is studied. Pioneering experiments are reported aimed at finding the temperature dependences of its insulating properties,
dielectric relaxation time, and activation energy for polarization relaxation. The measurements are taken at a variable signal
applied to the composite.
Heterogeneous catalysts that accelerate the photolytic destruction of organic contaminants in water are a potentially inexpensive and highly effective way to remove both trace-level and saturated harmful compounds from industrial waste streams and drinking water. Porous photocatalytic materials can have the combined qualities of high surface area and relatively large particle sizes, as compared with nanoparticulate catalyst powders like titanium dioxide . The larger particle sizes of the porous materials facilitate catalyst removal from a solution, after purification has taken place.
We have synthesized new kinds of photocatalytic porous oxide materials that can be used to purify contaminated water by accelerating the photodegradation of any kind of organic pollutant. The new materials have very large open pore structures that facilitate the diffusion, the surface contact of contaminants, and solvent flow through the catalyst. These qualities enhance surface reactions important to the process. The new catalysts have shown robust physical and chemical properties that make them candidates for real applications in polluted water decontamination.
In this paper, we describe the preparation and characterization of colloidal Cu nanoparticles/chitosan composite film (composite
film) by solution-casting technique with microwave heating. Effects of the incorporation of colloidal Cu nanoparticles on
structure, thermal behavior, surface, barrier properties and light transmission of composite film were investigated. The antimicrobial
activity of films against Staphylococcus aureus and Salmonella enterica serovar Typhimurium, were also tested. Incorporation of colloidal Cu nanoparticles on chitosan matrix improved the barrier
properties of films, decreasing the oxygen permeability as well as water vapor permeability and increasing the protection
against UV light. The composite film was effective in alteration of cell wall and reduction of microbial concentration in
the liquid culture for both bacteria tested.
Nanosilver has become one of the most widely used nanomaterials in consumer products because of its antimicrobial properties. Public concern over the potential adverse effects of nanosilver's environmental release has prompted discussion of federal regulation. In this paper, we assess several classes of consumer products for their silver content and potential to release nanosilver into water, air, or soil. Silver was quantified in a shirt, a medical mask and cloth, toothpaste, shampoo, detergent, a towel, a toy teddy bear, and two humidifiers. Silver concentrations ranged from 1.4 to 270,000 microg Ag g product(-1). Products were washed in 500 mL of tap water to assess the potential release of silver into aqueous environmental matrices (wastewater, surface water, saliva, etc.). Silver was released in quantities up to 45 microg Ag g product(-1), and size fractions were both larger and smaller than 100 nm. Scanning electron microscopy confirmed the presence of nanoparticle silver in most products as well as in the wash water samples. Four products were subjected to a toxicity characterization leaching procedure to assess the release of silver in a landfill. The medical cloth released an amount of silver comparable to the toxicity characterization limit. This paper presents methodologies that can be used to quantify and characterize silver and other nanomaterials in consumer products. The quantities of silver in consumer products can in turn be used to estimate real-world human and environmental exposure levels.
Silver-based antibacterial hybrid materials have been developed by in situ reduction of silver nitrate (1%) adsorbed on cellulose fibers by thermal and UV treatments. Microscopy revealed that the silver nanoparticles were dispersed and regular in shape. Migrated silver ions achieved 60 ppm in beef meat exudates. The ability of the silver-loaded absorbent pads to lower microbial contamination of exuded fluids was studied during storage of beef meat in modified atmosphere packaging. Cellulose-silver hybrid materials reduced the levels of the major microbial groups (total aerobic bacteria, lactic acid bacteria, Pseudomonas spp., and Enterobacteriaceae) present in the absorbent pads by an average of 1 log CFU/g during the entire storage period. The levels of total aerobic bacteria and Pseudomonas spp. were significantly reduced in the presence of silver ions, whereas lactic acid bacteria were less sensitive and not significantly affected. Enterobacteriaceae levels remained under the detection limit when silver was present. Neither the color of the meat nor the microbial loads were markedly affected by the presence of the silver-based antimicrobial hybrid materials.
Silver-montmorillonite (Ag-MMT) antimicrobial nanoparticles were obtained by allowing silver ions from nitrate solutions to replace the Na(+) of natural montmorillonite and to be reduced by thermal treatment. The Ag-MMT nanoparticles were embedded in agar, zein, and poly(ε-caprolactone) polymer matrices. These nanocomposites were tested in vitro with a three-strain cocktail of Pseudomonas spp. to assess antimicrobial effectiveness. The results indicate that Ag-MMT nanoparticles embedded into agar may have antimicrobial activity against selected spoilage microorganisms. No antimicrobial effects were recorded with active zein and poly(ε-caprolactone). The water content of the polymeric matrix was the key parameter associated with antimicrobial effectiveness of this active system intended for food packaging applications.
The antibacterial efficiency of Ag- and Zn-zeolites and the bactericidal action of Ag-zeolite-kneaded polyethylene films were examined in terms of their zeolite type (amorphous or crystalline zeolite Y and A). The MIC values of Ag- and Zn-zeolite (Sievelite) against Staphylococcus aureus showed that the antibacterial efficiency of Ag-zeolite is superior to those of Zn- and Cu-zeolite, and zeolite Y is more effective than zeolite A as an anti-bacterial zeolite. In the case of Ag-zeolite-kneaded polyethylene films without a dispersing agent, the bactericidal activity of the film increased proportionally with the increase of the amount of silver ion exchanged in zeolite particles though small amounts of silver ion were eluted. The kinetic analysis of the bactericidal action of the films showed that the decrease of the living cells were in line with first-order kinetics with regard to the amount of silver ions exchanged. In the experiments of time course changes in living cells, the bactericidal activity of the films was enhanced during the incubation of the films and the living cells of S. aureus in phosphate buffer. Thus the bactericidal efficiency appeared to increase due to the active species (possibly active oxygen species) eluted from inside the film.
Absorption kinetics of three different forms of the same iron-based oxygen scavenger were studied. Oxygen scavengers were used as pellet, sheet, and film materials. Two scavenger concentrations were used for sheet and film forms. Scavenger samples were analyzed at 75 or 100% relative humidities and stored at 5, 15, and 25°C. Oxygen concentration in the headspace was measured as a function of time. Absorption kinetics was best described by the Chapman-Richards empirical growth model rather than by a first-order reaction. Arrhenius behavior was observed for variations in the final absorption rate with temperature. Absorption capacities, final absorption rates, and activation energies were evaluated and discussed. Scavenger concentration, relative humidity, and temperature effects on kinetic parameters were studied for each experimental condition. Temperature was the most important factor that affected kinetic parameters. At the relative humidity levels studied, any important effect on kinetic parameters was not observed, except on absorption capacities.
In the present study, untreated and silver exchanged natural zeolite–polypropylene (PP) composites were prepared and characterized by means of different techniques (TGA, DSC, mechanical tests, density measurements, optical microscopy and colorometer). The effects of zeolite loading and silver concentration on the composite properties were investigated. The thermal characterization studies showed that the addition of the zeolite increased the crystallinity of the composites acting as a nucleating agent in PP crystallization and retarded the degradation of PP. At low silver concentrations, the zeolite behaved as a decelerating agent in PP degradation, however at higher silver concentrations, the composites degraded at a faster rate than pure PP. The experimental densities of the composites were found to be lower than the theoretical densities. When the tensile tested samples are considered, the densities were even lower indicating porous structure of the films. From the optical micrographs of the tensile tested films, it was clearly seen that the stretching along the machine direction caused hole formation around the particles. The optimum conditions obtained in this study for the PP–silver zeolite composite film production are in the range of 2–4wt% zeolite treated with 4.36mg Ag+/g zeolite. At higher zeolite loadings, the film becomes brittle and at higher Ag+ concentrations, the film produced was discolored.
Silver nanoparticles have recently gained increasing interests due to their antimicrobial activities in food processing applications. The aim of this study was to evaluate the effect of silver nanoparticles-PVP coating on weight loss, ascorbic acid, total chlorophyll, crude fiber, color, firmness and microbial qualities of asparagus spears stored at 2 and 10°C. Asparagus samples were first sanitized with 100mgl−1 sodium hypochloride solution for 15min. They were then immersed in coating solution containing silver nanoparticles for 3min at room temperature. During 25-day storage at 2 or 10°C, the coated asparagus demonstrated lower weight loss, greener color and tender texture compared with the control samples. The growth of microorganism was significantly hindered by the coating. Based on comprehensive comparison and evaluation, asparagus spears coated by silver nanoparticles could be kept in good quality for 25 days at 2°C and for 20 days at 10°C.
Since the market for minimally processed foods is broadening, packaging is being implemented in strategies that actively contribute to the food preservation and transformation concepts. One opportunity is given by the incorporation of biocatalysts, usually in prefabricated carriers, where they can fully retain their activity. These biocatalysts can be repeatedly reused within the packaging or, under controlled conditions, migrate to the product. The potential use of packages composed of classic polymers with functional surfaces or highly swellable biopolymers is being successfully tested, showing good perspectives for the controlled release when directly used in contact with the product or as part of combined strategies. Moreover, new nanostructured materials (modified clays, LBL assemblies, electrospun fibres) are being implemented as part of more innovative solutions. This review summarizes the most recent developments and upcoming possibilities to incorporate biocatalysts in polymers traditionally used in food packaging applications and in some recently introduced biopolymers.
Modification of the rheological properties of cellulose acetate phthalate in 2-methoxyethanol/
acetone/water, at different compositions of solvent mixtures, allowed the identification
of optimal composition of solvent mixtures for obtaining fibers with controlled diameters.
Changing the solvent content in the casting solutions favors modification of the morphological
aspects of cellulose acetate phthalate (CAP) films, as observed from atomic force
microscopy images. Silver nitrate was incorporated into CAP, as a dispersion medium,
and the silver-containing polymer (Ag-CAP) films thus obtained were studied for obtaining
information on antimicrobial activity, using Escherichia coli ATCC 10536 and Staphylococcus
aureus ATCCC 6538 microorganisms. The results were compared with the antibacterial
activity of nano-silver-containing cellulose acetate (Ag-CA) films. The different
inhibiting effects of CA or Ag-CA and of CAP or Ag-CAP on the tested Escherichia coli
and Staphylococcus aureus bacteria are due to a different antimicrobial activity of the polymers
and to the antiseptic character of nano-silver.
Abstract: In this article, an instrument is presented to diagnose microbial safety control activities in a food safety management system. The need of such a tool is derived from the importance of microbial safety control and the need for improvement of existing control systems. Careful diagnosis of these systems provides the basis for their improvement. The diagnostic instrument provides a comprehensive checklist of crucial control activities, addressing major technology-dependent and managerial activities in design and operation of preventive measures, intervention processes, and monitoring systems. Secondly, it provides detailed grids describing three levels of execution for each safety control activity to enable a differentiated assessment of ones food safety control system situation. The basic assumption underlying the diagnostic instrument is that activities on a higher level are more predictable and better able to achieve a desired safety outcome, due to more insight in underlying mechanisms and more accurate information. Finally, we discuss that using the instrument may contribute in finding effective types and levels of control activities within given contextual dependencies.
With palladium chloride supported on active charcoal, ethylene was catalytically oxidized by oxygen to acetaldehyde in the vapor phase. Selectivity and activity were very high. Steam was essential for the formation of acetaldehyde and the rate increased markedly with rise in steam concentration but decreased with rise in temperature, providing an apparent activation energy of -18 kcal/mol. Small ratios of butenes and carbon dioxide were formed but the selectivity of acetaldehyde was about 99% under the determined optimum condition. The kinetics suggest that the catalysis of the reaction consisted of the reduction of palladium salt by ethylene and water to give acetaldehyde and reduced palladium and reoxidation of reduced palladium by oxygen with the catalysis of active charcoal. Reduction of palladium chloride by ethylene and water, which gives acetaldehyde, is considered to proceed along a path that is substantially the same as that of liquid homogeneous systems. Oxidation of reduced palladium is considered to take place by dissociatively adsorbed oxygen on active charcoal. Reaction of other olefins was also studied; the main products were methyl ketones. Reactivity was in the following order: ethylene > propylene > 1-butene ≃ cis-2-butene > trans-2-butene.
Nanoscale particles of metallic copper clusters have been prepared by two methods, namely the thermal reduction and sonochemical reduction of copper(II) hydrazine carboxylate Cu(N2H3COO)2·2H2O complex in an aqueous medium. Both reduction processes take place under an argon atmosphere over a period of 2−3 h. The FT-IR, powder X-ray diffraction, and UV−visible studies support the reduction products of Cu2+ ions as metallic copper nanocrystallites. The powder X-ray analysis of the thermally derived products show the formation of pure metallic copper, while the sonochemical method yields a mixture of metallic copper and copper oxide (Cu2O). The formation of Cu2O along with the copper nanoparticles in the sonochemical process can be attributed to the partial oxidation of copper by in situ generated H2O2 under the sonochemical conditions. However, the presence of a mixture of an argon/hydrogen (95:5) atmosphere yields pure copper metallic nanoparticles, which could be due to the scavenging action of the hydrogen towards the OH• radicals that are produced in solution during ultrasonic irradiation. The synthesized copper nanoparticles exhibit a distinct absorption peak in the region of 550−650 nm. The transmission electron microscopy studies of the thermally derived copper show the presence of irregularly shaped particles (200−250 nm) having sharp edges and facets. On the other hand, the sonochemically derived copper powder shows the presence of porous aggregates (50−70 nm) that contain an irregular network of small nanoparticles. The copper nanoparticles are catalytically active toward an “Ullmann reaction”that is, the condensation of aryl halides to an extent of 80−90% conversion. The time course of catalysis was studied for condensation of iodobenzene at 200 °C for a period of 1−5 h. The catalytic ability of copper nanoparticles produced by the thermal and sonochemical methods was compared with that of commercial copper powders.
The optical absorption of the colloidal nanoparticles is investigated, formed by the UV illumination of aqueous solutions containing AgClO4 ((1−4) × 10-4 M), acetone (2 × 10-2 M), 2-propanol (1 M), and various polymer stabilizers. The 7 nm particles, which are produced in the presence of polyethyleneimine, possess an unusally narrow plasmon absorption band. The wavelength and shape of this band are affected by various adsorbed solutes; adsorption phenomena can therefore be studied spectrophotometrically. The changes in band shape that occur in the presence of oxygen and of carbon tetrachloride are attributed to a partial oxidation of the silver particles by these solutes. During the oxidation, the Fermi level in the nanoparticles shifts to a more positive potential, until the oxidation comes to a halt. Chemisorbed metal cations (Cd2+, Ni2+, Ag+, Hg2+) affect the plasmon absorption band of the silver nanoparticles more strongly the more electropositive is the metal. The effect is interpreted in terms of the donation of electron density from the silver particles to the adsorbed cations. In the case of Hg2+ ions, the electron donation leads to partial Ag oxidation and amalgam formation. UV illumination of a sol that contains Cd2+ ions produces Cd metal on the surface of the silver particles.
Copper and nickel nanoparticles were synthesized in the insoluble microcrystalline cellulose support by reduction of metal ions with several reducers in various media resulting in cellulose-metal nanocomposites. Wide-angle X-ray scattering results showed that supramolecular structure of cellulose did not change. Crystalline Cu2O and Cu0 nanoparticles were prepared with reducers NaBH4 and N2H4 · H2SO4, CuO nanoparticles – with cellulose itself as a reducer. Crystalline Ni0 nanoparticles were synthesized with N2H4 · 2HCl and NaBH4; Ni0 nanoparticles in amorphous form were prepared with KH2PO2 · H2O. SEM revealed large agglomerates of metal particles on the fibre surface. ASAXS and TEM have shown the nanoparticles to be in the range 5–55 nm.
The effectiveness of Ag+-based antimicrobial film in inhibiting the growth of an Alicyclobacillus acidoterrestris strain was assessed. The proposed active film was obtained by depositing via plasma an Ag-containing polyethylenoxide-like coating on a polyethylene layer. Tests were conducted at 44 °C, monitoring the viable cell concentration of the investigated microorganism into 2 different media: acidified malt extract broth and apple juice. Results indicate that the investigated active film successfully inhibited the growth of A. acidoterrestris in both media. Results also indicate that the effectiveness of the film depends on the type of medium tested.
In this study, antibacterial properties were induced in polyurethane (PU) films by the incorporation of Ag+-loaded zeolites as fillers. The mechanical and thermal properties of the prepared composites were also investigated. For this purpose, two different types of zeolite microparticles, high-silica zeolite beta crystals and low-silica zeolite A crystals, were synthesized. Ag+ was added by ion exchange, and these particles were incorporated into the PU prepolymer, which was prepared from its main components of toluene diisocyanate and polypropylene ethylene glycol (medical purity). Microbiological tests revealed that both types of composites, prepared by the addition of Ag+-containing zeolite beta or zeolite A to the PU matrix, had antibacterial properties. It was demonstrated for the first time that a high-silica zeolite (zeolite beta) and its composite film could be effectively employed as antibacterial materials. Furthermore, mechanical and thermal characterization of the composites showed that the zeolites enhanced the mechanical properties of the polymer and did not cause any deterioration in its thermal properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
In this work, the effects of two different amounts of zinc oxide (ZnO) nanoparticles on the antimicrobial activities of poly (vinyl chloride)-based films to inactivate food pathogens were investigated. Results showed that the ZnO-coated film exhibited a good inhibition effect on the growth of Escherichia coli and Staphylococcus aureus and its ability was attributed to the ZnO nanoparticles. The ZnO-coated films exhibited more effective antibacterial activity for S. aureus. However, antifungal activity of the ZnO-coated films (20 mm × 25 mm) against Aspergillus flavus and Penicillium citrinum was not observed. It is likely due to the complexity of the fungal cell wall and the ZnO nanoparticles without UV light irradiated or the insufficient amount of nanoparticles. Our findings reveal that ZnO nanoparticles have a good potential to be coated on a plastic film to make antimicrobial packaging against bacteria such as E. coli and S. aureus.
This work describes the release of copper(II) ions from cellulose fibers, which have been chemically modified by periodate-induced oxidation of cellulose, followed by covalent attachment of biopolymer chitosan. The release of copper(II) ions has been investigated in physiological fluid (PF) and protein solution (PS) both at 37°C. Fibers have demonstrated excellent antibacterial activity against E. coli. Finally, their borohydride-induced reduction has yielded copper nanoparticle-loaded fibers, with average diameter of particles, nearly 28.94 nm. The formation of copper nanoparticles has been established by surface plasmon resonance and FTIR spectroscopy. These fibers also show fair biocidal action against E. coli. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Nanocomposite materials obtained by TiO2 incorporation into ethylene–vinyl alcohol copolymers, extensively used in food packaging, are prepared via a straightforward melting process. The structural characteristics of the nanocomposites are examined using wide and small angle X-ray scattering (WAXS/SAXS), and vibrational infrared and Raman spectroscopies. A microscopy (SEM/TEM) study shows that the materials obtained are highly homogeneous at the nanometric scale, exhibiting an intimate contact between both the organic and inorganic components. TiO2 incorporation into this polymer matrix renders self-sterilized nanocomposite materials upon light excitation, which are tested against nine micro-organisms (gram-positive and gram-negative bacteria, cocci, and yeasts) typically involved in food contamination and/or degradation. Overall, the nanocomposites display an impressive performance in the killing of all micro-organisms with a maximum for an oxide content between 2–5 wt %. The measurement of the physico-chemical properties together with the structural characterization of the materials provide conclusive evidence that the nanocomposites biocidal capability born of the nanometric organo-inorganic interface and rationalize the existence of a maximum as a function of the TiO2 content.
It was found for the first time that polymer nanofibers containing Ag nanoparticles on their surface could be produced by UV irradiation of polymer nanofibers electrospun with small amounts of silver nitrate (AgNO3). When the cellulose acetate (CA) nanofibers electrospun from CA solutions with 0.5 wt% of AgNO3 were irradiated with UV light at 245 nm, Ag nanoparticles were predominantly generated on the surface of the CA nanofibers. The number and size of the Ag nanoparticles were continuously increased up to 240 min. The Ag+ ions and Ag clusters diffused and aggregated on the surface of the CA nanofibers during the UV irradiation. The Ag nanoparticles with an average size of 21 nm exhibited strong antimicrobial activity.
Semitransparent composite films were pre-pared made from TiO 2 nanotubes in chitosan (CS) matrix. Hydrothermally synthesized titanium nanotubes (TiNTs) were dispersed in chitosan matrix in order to produce film-forming solutions at 0.05 and 0.10% w/v. Structural, topo-logical, optical and thermal properties of these films were evaluated. The antimicrobial activity of films against Salmo-nella enterica serovar Typhimurium, Escherichia coli (Gram-negatives) and Staphylococcus aureus (Gram-positive) was also investigated. Fourier transform infrared (FTIR) spectra showed effective site-selective interactions between chito-san and TiNTs. TiNTs prevented the degradation of films, avoiding the oxidization of the glucosamine ring. Charac-terizing techniques such as, Scanning electron microscopy– energy dispersive spectroscopy (SEM-EDS) line profile and atomic force microscopy (AFM) were used to examine the TiNTs dispersion within the film. The morphological analy-sis indicated that the TiNTs were well dispersed and became clustered proportionally to the weight percentage of TiNTs used in the composites. The UV-Vis spectra showed that TiNTs increased the film absorption in the UV region and the light barrier properties of films remained stable over the storage period. Photoacoustic spectroscopy (PAS) was used to study these films, nondestructively for their thermal effu-sivity (e). The films were effective in reducing the microbial concentration in the liquid culture for all bacteria tested. The effectiveness was found to dependent on the bacterial strain and TiNTs content. V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 3503–3515, 2010
Outbreaks of food-borne pathogens, such as Escherichia coli O157:H7 and Salmonella, continue to draw public attention to food safety. Several reports have demonstrated the efficacy of using natural ingredients to control the growth of food-borne pathogens. The objective of this study was to investigate antimicrobial effects of lactic acid and copper, alone and in combination, on the survival and growth of Salmonella spp. and E. coli O157:H7 in laboratory medium and carrot juice. Survival and growth of 38 Salmonella spp. and six E. coli O157:H7 strains were compared when grown in brain heart infusion (BHI) broth and carrot juice under conditions including either lactic acid (0.2%) alone, copper sulfate (50ppm) alone or the combination of the two. The growth inhibition was negligible when copper sulfate was added to BHI broth and carrot juice. Lactic acid (0.2%) retarded the growth of bacterial strains. However, the growth of bacterial strains was significantly inhibited when both lactic acid and copper were in BHI broth and carrot juice within the time frame of this study. These findings indicated that lactic acid, in combination with copper sulfate, could be used to inhibit the growth of pathogens. Natural ingredients, such as lactic acid and low dose of copper ions, can be used to improve the safety of food products.
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A new in situ infusion method was used to incorporate small amounts (∼1 wt %) of metal and metal oxide particles into a polymer matrix. Nanosized particles were observed by both transmission electron microscopy and atomic force microscopy. Oxygen (O2) and carbon dioxide (CO2) transport properties of the infused materials were investigated using a dynamic diffusion approach in which both testing and purge gases can be controlled. It was discovered that trace amounts (∼2%) of hydrogen (H2) in the purge gas were sufficient to considerably reduce the O2 flux of FEP films infused with palladium (Pd) nanoparticles, up to a 200-fold decrease. In contrast, H2 essentially had no effect on the transport of CO2. The generality of the remarkable reduction in oxygen flux was also demonstrated with films of PP, LLDPE, PET, and nylon 6,6 infused with Pd nanoparticles. This oxygen-scavenging effect became more pronounced at lower oxygen concentrations. The catalytic role of Pd in the reaction of O2 and H2 and the enormous surface area provided by the dispersed nanoparticles were responsible for this highly efficient oxygen-scavenging effect. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 749–756, 2004
The effect of a novel nano-packing material on preservation quality of Chinese jujube (Ziziphus jujuba Mill. var. inermis (Bunge) Rehd) during room temperature storage was investigated. The nano-packing material with lower relative humidity, oxygen transmission rate and high longitudinal strength (2.05 g/m2 24 h, 12.56 cm3/m2 24 h 0.1 MPa and 40.16 MPa, respectively) was synthesized by blending polyethylene with nano-powder (nano-Ag, kaolin, anatase TiO2, rutile TiO2). The results showed that the nano-packing material had a quite beneficial effect on physicochemical and sensory quality compared with normal packing material. After 12-day storage, fruit softening, weight loss, browning and climatic evolution of nano-packing were significantly inhibited. Meanwhile, the contents of titrable acid and ascorbic acid were decreased to 0.21%, 251 mg/100 g, for nano-packing and 0.15%, 198 mg/100 g, for normal packing; The contents of total soluble sugar, reducing sugar, total soluble solids and malondialdehyde were increased to 28.4%, 5.2%, 19.5% and 98.9 μmol/g for nano-packing and 30.0%, 6.3%, 23.1% and 149 μmol/g for normal packing. Therefore, the nano-packing could be applied for preservation of Chinese jujube to expand its shelf life and improve preservation quality.
Hydrogel networks based on N-isopropylacrylamide (NIPAM) and sodium acrylate (SA) were prepared by redox-polymerization in the presence of N,N′-methylenebisacrylamide (MBA). Highly stable and uniformly distributed silver nanoparticles have been prepared using these hydrogel networks as a carrier via in situ reduction of silver nitrate in the presence of sodium borohydride as a reducing agent. It has been demonstrated that the hydrogel hybrid with different sizes of silver nanoparticles can be effectively employed as antibacterial material.
Antimicrobial materials based on hydroxyapatite are potentially attractive in a wide variety of medical applications. The synthesis of copper and zinc-doped hydroxyapatite was done by neutralization method. This method consists of dissolving CuO or ZnO in solution of H3PO4, and the slow addition to suspension of Ca(OH)2 for obtaining monophasic product. Characterization studies from XRD, SEM, TEM and FTIR spectra showed that particles of all samples are of nano size and they do not contain any discernible crystalline impurity. The quantitative elemental analysis showed that the copper and zinc ions fully incorporated into the hydroxyapatite. The antimicrobial effects of doped hydroxyapatite powders against pathogen bacterial strains Escherichia coli, Staphylococcus aureus and pathogen yeast Candida albicans were tested in solid and liquid media. Quantitative test in liquid media clearly showed that copper and zinc-doped samples had viable cells reduction ability for all tested strains.
Montmorillonite sol was passed through a column charged with the cation exchange resin supported by Ag+ to convert into Ag+-exchanged montmorillonite sol. The thin film and fine particles were prepared from the resulting Ag+-exchanged montmorillonite sol of which the Ag content was about 10 wt%. These specimens exhibited strong antimicrobial activity to both Staphylococcus aureus and Escherichia coli, and antifungal activity to Aspergillus niger. Fine silver particles were deposited more abundantly with increasing the heating temperature to 800°C, leading to a lowering of antimicrobial activity.
Silver nanoparticles have been formed in fluff pulp and nanostructured Lyocell fibres by immersion in silver nitrate, and a subsequent transformation of the adsorbed silver ions into elementary silver nanoparticles by physical (thermal/UV) or chemical (sodium borohydride) methods. Microscopy revealed that nanoparticles generated by physical methods were regular in shape and efficiently dispersed, while the chemical reduction produced highly aggregated nanoparticles. Nanoparticle size has been found relevant to guarantee high antimicrobial activity, being the samples with big aggregated silver nanoparticles almost inefficient. Indeed a satisfactory correlation between silver ion release and the antimicrobial efficiency against Escherichia coli and Staphylococcus aureus could be confirmed, and furthermore, the highest concentrations tested were efficient to reduce the microbial load in poultry exudates. This work demonstrates that especially designed absorbent materials could be optimised to preserve aseptic conditions during manipulation, leading to feasible applications of a silver based nanotechnology in food technology.
Research and development of antimicrobial materials for food applications such as packaging and other food contact surfaces is expected to grow in the next decade with the advent of new polymer materials and antimicrobials. This article reviews the different types of antimicrobial polymers developed for food contact, commercial applications, testing methods, regulations and future trends. Special emphasis will be on the advantages/disadvantages of each technology.
A well-adherent surface of titanium oxide nanoparticles was produced on cellulose fibers at low temperature from an aqueous titania sol that was obtained via hydrolysis and condensation reactions of titanium isopropoxide in water. SEM investigations of the formed titania films revealed a semi-spherical particle morphology with grain size about 10 nm in diameter. The coated substrates showed substantial bactericidal properties under UV radiation, ambient fluorescent white light and dark conditions. The possible mechanisms for the antibacterial activity are discussed. The stability of the titania coatings was investigated by comparing the UV transmission profiles of coated fibers before and after repeated washing.
The fabrication of silver nanoparticles was accomplished by γ-ray irradiation reduction of silver nitrate in a chitosan solution. The obtained nanoparticles were stable in the solution for more than six months, and showed the characteristic surface plasmon band at 411 nm as well as a positively charged surface with 40.4 ± 2.0 mV. The silver nanoparticles presented a spherical shape with an average size of 20–25 nm, as observed by TEM. Minimum inhibitory concentration (MIC) against E. coli, S. aureus and B. cereus of the silver nanoparticles dispersed in the γ-ray irradiated chitosan solution was 5.64 µg/mL. The silver nanoparticle-loaded chitosan–starch based films were prepared by a solution casting method. The incorporation of silver nanoparticles led to a slight improvement of the tensile and oxygen gas barrier properties of the polysaccharide-based films, with diminished water vapor/moisture barrier properties. In addition, silver nanoparticle-loaded films exhibited enhanced antimicrobial activity against E. coli, S. aureus and B. cereus. The results suggest that silver nanoparticle-loaded chitosan–starch based films can be feasibly used as antimicrobial materials for food packaging and/or biomedical applications.
Escherichia coli expressing recombinant green fluorescent protein was used to test the bactericidal efficacy of a newly synthesized chitosan–Ag-nanoparticle composite. The composite was found to have significantly higher antimicrobial activity than its components at their respective concentrations. The one-pot synthesis method led to the formation of small Ag nanoparticles attached to the polymer which can be dispersed in media of pH ≤ 6.3. The presence of a small percentage (2.15%, w/w) of metal nanoparticles in the composite was enough to significantly enhance inactivation of E. coli as compared with unaltered chitosan. Fluorescence spectroscopy indicated that bacterial growth stopped immediately after exposure of E. coli to the composite, with release of cellular green fluorescent protein into the medium at a faster rate than with chitosan. Fluorescence confocal laser scanning and scanning electron microscopy showed attachment of the bacteria to the composite and their subsequent fragmentation. Native protein gel electrophoresis experiments indicated no effect of the composite on bacterial proteins.
Nanocomposite LDPE films containing Ag and ZnO nanoparticles were prepared by melt mixing in a twin-screw extruder. Packages prepared from the films were then filled with fresh orange juice and stored at 4 °C. Microbial stability, ascorbic acid (AA) content, browning index, color value, and sensory attributes of them were evaluated after 7, 28, and 56 days of storage. Packages containing the nanomaterials, expect 1% nano-ZnO, kept the microbial load of fresh juice below the limit of microbial shelf life (6 log cfu/ml) up to 28 days The least degradation of AA (80.50 mg/100 g), development of brown pigments (OD = 0.23) and losing of color (∆E = 6.0) were observed in pouches containing 0.25% nano-ZnO, after the same time. Sensory attributes were also ranked highest for the juice thus packed in the recent packages after 28 days (p < 0.05). Packages containing nanosilver increased shelf life of fresh juice although part of its sensory attributes were lost.Industrial relevanceCompared with pure packaging materials, antimicrobial nanocomposite packages containing Ag and ZnO as an alternative non-thermal technology can extend the shelf life of fresh orange juice up to 28 days. However, a certain concentration of nano-ZnO in the packages showed less adverse effects on sensory characteristics.
The paper focuses on the synthesis of chitosan nanoparticles (CSN) by ionic gelation with sodium tripolyphosphate and subsequently its loading with silver ions to produce silver loaded chitosan nanoparticles (Ag-CSN). The aim was to enhance the antibacterial property of chitosan in the nanoparticle form and thus improve its bactericidal efficacy when applied on polyester fabrics. The average particle size of CSN and Ag-CSN was 115 nm and 165 nm, respectively. The structure of CSN and Ag-CSN was studied by XRD, FTIR, DSC, TGA and TEM analysis. The minimum inhibitory concentration of both the CSN and Ag-CSN against Staphylococcus aureus bacteria was found to be 50 and 500 times less, respectively, as compared to bulk chitosan. Silver loading on the synthesized CSN showed synergistic antimicrobial effect against S. aureus bacteria. The release of Ag+ from Ag-CSN finished polyester fabric is substantiated by antibacterial testing which shows a clear zone of inhibition.
The objective of this work was to evaluate the effectiveness of an antimicrobial packaging system containing active nanoparticles on the quality deterioration of Fior di Latte cheese. To this aim, 3 concentrations of silver montmorillonite embedded in agar were used. The cell loads of spoilage and useful microorganisms were monitored during a refrigerated storage period. Moreover, cheese sensory quality (i.e., odor, color, consistency, and overall quality) was evaluated by means of a panel test. Results showed that the active packaging system markedly increased the shelf life of Fior di Latte cheese, due to the ability of silver cations to control microbial proliferation, without affecting the functional dairy microbiota and the sensory characteristics of the product. The active packaging system developed in this work could be used to prolong the shelf life of Fior di Latte and boost its distribution beyond local market borders.