Polymeric Antimicrobial Food Packaging and Its Applications

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

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

Future foods: Alternative proteins, food architecture, sustainable packaging, and precision nutrition

There are numerous challenges facing the modern food and agriculture industry that urgently need to be addressed, including feeding a growing global population, mitigating and adapting to climate change, decreasing pollution, waste, and biodiversity loss, and ensuring that people remain healthy. At the same time, foods should be safe, affordable, convenient, and delicious. The latest developments in science and technology are being deployed to address these issues. Some of the most important elements within this modern food design approach are encapsulated by the MATCHING model: Meat-reduced; Automation; Technology-driven; Consumer-centric; Healthy; Intelligent; Novel; and Globalization. In this review article, we focus on four key aspects that will be important for the creation of a new generation of healthier and more sustainable foods: emerging raw materials; structural design principles for creating innovative products; developments in eco-friendly packaging; and precision nutrition and customized production of foods. We also highlight some of the most important new developments in science and technology that are being used to create future foods, including food architecture, synthetic biology, nanoscience, and sensory perception.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2033683.

Antimicrobial and indicator properties of edible film containing clove bud oil-loaded chitosan capsules and red cabbage for fish preservation

For safe preservation and consumption of fish, freshness monitoring and antimicrobial control is crucial. Edible films comprising natural antimicrobial and spoilage indicator agents represent a convenient method for such preservation. Edible chitosan-based films were prepared using red cabbage (RC) and clove bud oil (CBO)-loaded chitosan/carrageenan capsules as spoilage indicator and antimicrobial agents, respectively. CBO-loaded capsules were prepared by the ionic gelation of chitosan and carrageenan. Films containing CBO capsules exhibited significantly higher antimicrobial activity than films containing non-encapsulated free CBO, as confirmed by minimum inhibitory concentration and time-kill assays. The highest antimicrobial activity was observed in the largest capsules (1.7 μm). After incubation for 48 h, the pH of fish peptone agar containing Pseudomonas fluorescens increased from approximately 6.0 to 9.0, and a color change from purple to deep blue was clearly observed during the growth of fish-spoiling bacteria. Thus, our results suggested that edible films containing CBO-loaded capsules and RC showed the potential to inhibit microbial growth in fish and to visibly indicate fish freshness.

Development of Inclusion Complexes With Relative Humidity Responsive Capacity as Novel Antifungal Agents for Active Food Packaging

Background: Allyl isothiocyanate is an excellent antimicrobial compound that has been applied in the development of active food packaging materials in the last years. However, the high volatility of this compound could prevent a lasting effect over time. In order to avoid this problem, cyclodextrin inclusion complexes have been proposed as an alternative, being beta-cyclodextrin (β-CD) as the main candidate. In addition, β-CD could act as a relative humidity-responsive nanoparticle. In this regard, the aim of this study was to develop inclusion complexes based on β-CD and AITC as relative humidity-responsive agents, which can be used in the design of active food packaging materials. Methods: Two different β-CD:AITC inclusion complexes (2:1 and 1:1 molar ratios) were obtained by the co-precipitation method. Entrapment efficiency was determined by gas chromatography, while inclusion complexes were characterized through thermal, structural, and physicochemical techniques. Antifungal capacity of inclusion complexes was determined in a headspace system. Furthermore, the AITC release from inclusion complexes to headspace at different percentages of relative humidity was evaluated by gas chromatography, and this behavior was related with molecular dynamic studies. Key Findings and Conclusions: The entrapment efficiency of inclusion complexes was over to 60%. Two coexisting structures were proposed for inclusion complexes through spectroscopic analyses and molecular dynamic simulation. The water sorption capacity of inclusion complexes depended on relative humidity, and they exhibited a strong fungicide activity against Botrytis cinerea. Furthermore, the AITC release to headspace occurred in three stages, which were related with changes in β-CD conformational structure by water sorption and the presence of the different coexisting structures. In addition, a strong influence of relative humidity on AITC release was evidenced. These findings demonstrate that β-CD:AITC inclusion complexes could be used as potential antifungal agents for the design of food packaging materials, whose activity would be able to respond to relative humidity changes.

Influence of polyamide composite casings with silver-zinc crystals on the quality of beef and chicken sausages during their storage

The influence of polyamide 6 composite casings with silver-zinc crystals powder on some of the physicochemicalphysical-chemical, microbiological and sensory indicators of beef and chicken sausages during their storage was evaluated. Beef and chicken sausages were elaborated by using the conventional technology for sausage meat thin pasta; in each case, it was maintained a control batch to compare changes during the storage (4 and 12 °C, 75%-85% RH). To estimate the shelf life was considered sensory evaluation as a criterion for rejection. The results were processed as failure incomplete data via the Weibull distribution and it was admitted 5% of deteriorated units. It did not find a significant effect (p ≤ 0.05) due to the addition of silver-zinc crystals on the values of pH, aw, color, texture and sensory attributes of sausages, but did influence TBARS results, with lower values compared to control products. It reduced the counts of aerobic mesophilic microorganisms and lactic acid bacteria during the storage. The shelf life of chicken sausage was not affected at any storage temperature; while for the beef sausage stored at 4 °C, its shelf life increased in 9 days, although at 12 °C did not exist difference among treatments.

Algae bioprocess to deal with cosmetic chemical pollutants in natural ecosystems: A comprehensive review

Elevated demand and extensive exploitation of cosmetics in day-to-day life have hiked up its industrial productions worldwide. Organic and inorganic chemicals like parabens, phthalates, sulfates, and so forth are being applied as constituents towards the formulations, which tend to be the mainspring ecological complication due to their enduring nature and accumulation properties in various sections of the ecosystem. These cosmetic chemicals get accrued into the terrestrial and aquatic systems on account of various anthropogenic activities involving agricultural runoff, industrial discharge, and domestic effluents. Recently, the use of microbes for remediating persistent cosmetic chemicals has gained immense interest. Among different forms of the microbial community being applied as an environmental beneficiary, algae play a vital role in both terrestrial and aquatic ecosystems by their biologically beneficial metabolites and molecules, resulting in the biobenign and efficacious consequences. The use of various bacterial, fungal, and higher plant species has been studied intensely for their bioremediation elements. The bioremediating property of the algal cells through biosorption, bioassimilation, biotransformation, and biodegradation has made it favorable for the removal of persistent and toxic pollutants from the environment. However, the research investigation concerned with the bioremediation potential of the algal kingdom is limited. This review summarizes and provides updated and comprehensive insights into the potential remediation capabilities of algal species against ecologically hazardous pollutants concerning cosmetic chemicals.

Antibacterial Polymers Based on Poly(2-hydroxyethyl methacrylate) and Thiazolium Groups with Hydrolytically Labile Linkages Leading to Inactive and Low Cytotoxic Compounds

Herein, we develop a well-defined antibacterial polymer based on poly(2-hydroxyethyl methacrylate) (PHEMA) and a derivative of vitamin B1, easily degradable into inactive and biocompatible compounds. Hence, thiazole moiety was attached to HEMA monomer through a carbonate pH-sensitive linkage and the resulting monomer was polymerized via reversible addition-fragmentation chain transfer (RAFT) polymerization. N-alkylation reaction of the thiazole groups leads to cationic polymer with thiazolium groups. This polymer exhibits excellent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) with an MIC value of 78 µg mL-1, whereas its degradation product, thiazolium small molecule, was found to be inactive. Hemotoxicity studies confirm the negligible cytotoxicity of the degradation product in comparison with the original antibacterial polymer. The degradation of the polymer at physiological pH was found to be progressive and slow, thus the cationic polymer is expected to maintain its antibacterial characteristics at physiological conditions for a relative long period of time before its degradation. This degradation minimizes antimicrobial pollution in the environment and side effects in the body after eradicating bacterial infection.

Trends and challenges of biopolymer-based nanocomposites in food packaging

The ultimate goal of new food packaging technologies, in addition to maintaining the quality and safety of food for the consumer, is to consider environmental concerns and reduce its impacts. In this regard, one of the solutions is to use eco-friendly biopolymers instead of conventional petroleum-based polymers. However, the challenges of using biopolymers in the food packaging industry should be carefully evaluated, and techniques to eliminate or minimize their disadvantages should be investigated. Many studies have been conducted to improve the properties of biopolymer-based packaging materials to produce a favorable product for the food industry. This article reviews the structure of biopolymer-based materials and discusses the trends and challenges of using these materials in food packaging technologies with the focus on nanotechnology and based on recent studies.

Recombinant production and characterisation of two chitinases from Rasamsonia emersonii, and assessment of their potential industrial applicability

Rasamsonia emersonii (previously Talaromyces emersonii) is a thermophilic filamentous fungus displaying optimum growth at 45 °C. It has a history of use in commercial food enzyme production. Its unfractionated chitinolytic secretome was partially characterised in the early 1990s; however, no individual chitinase from this source has been described in literature previously. This study describes two GH18 chitinases originating from the R. emersonii genome, expressed in the methylotrophic yeast P. pastoris. Chit1 comprises of a GH18 catalytic domain and Chit2 comprises of a GH18 catalytic domain and a chitin-binding motif at the C-terminal. The chitinases were expressed as glycoproteins. The apparent molecular weight of Chit1 was 35.8-42.1 kDa with a smearing tail associated with glyco-sidechains visible up to 72.2 kDa. This became two bands of 30.8 and 29.0 kDa upon de-glycosylation. The apparent molecular weight of Chit2 was 50.4 kDa, reducing to 48.2 kDa upon de-glycosylation. Both chitinases displayed endo-chitinase and chitobiosidase activity, temperature optima of 50-55 °C and low pH optima (pH 4.5 or lower); Chit1 displayed a pH optimum of 3.5, retaining > 60% maximum activity at pH 2.2, a pH range lower than most enzymes of fungal origin. Chit2 displayed the highest chitin-degrading ability at 3456 µmol/mg on 4-NP-triacetylchitotriose, but lost activity faster than Chit1, which displayed 403 µmol/mg on the same substrate. The predicted D values (time required to reduce the enzyme activity to 10% of its original value at 50 °C) were 19.2 and 2.3 days for Chit1 and Chit2, respectively. Thus, Chit1 can be considered one of few hyperthermostable chitinase enzymes described in literature to date. Their physicochemical properties render these chitinases likely suitable for shrimp chitin processing including one-step chitin hydrolysis and alternative sustainable protein processing and the attractive emerging application of mushroom food waste valorisation.Key points• Two GH18 chitinases originating from the industrially relevant thermophilic fungus R. emersonii were cloned and expressed in P. pastoris.• The purified recombinant chitinases showed low pH and high temperature optima and appreciable thermostability at industrially relevant temperatures.• The chitinases displayed characteristics that indicate their likely suitability to several industrial applications including sustainable alternative protein processing, food waste valorisation of commercial mushroom production and one-step shrimp chitin processing.

Engineered Bioactive Polymeric Surfaces by Radiation Induced Graft Copolymerization: Strategies and Applications

The interest in developing antimicrobial surfaces is currently surging with the rise in global infectious disease events. Radiation-induced graft copolymerization (RIGC) is a powerful technique enabling permanent tunable and desired surface modifications imparting antimicrobial properties to polymer substrates to prevent disease transmission and provide safer biomaterials and healthcare products. This review aims to provide a broader perspective of the progress taking place in strategies for designing various antimicrobial polymeric surfaces using RIGC methods and their applications in medical devices, healthcare, textile, tissue engineering and food packing. Particularly, the use of UV, plasma, electron beam (EB) and γ-rays for biocides covalent immobilization to various polymers surfaces including nonwoven fabrics, films, nanofibers, nanocomposites, catheters, sutures, wound dressing patches and contact lenses is reviewed. The different strategies to enhance the grafted antimicrobial properties are discussed with an emphasis on the emerging approach of in-situ formation of metal nanoparticles (NPs) in radiation grafted substrates. The current applications of the polymers with antimicrobial surfaces are discussed together with their future research directions. It is expected that this review would attract attention of researchers and scientists to realize the merits of RIGC in developing timely, necessary antimicrobial materials to mitigate the fast-growing microbial activities and promote hygienic lifestyles.

Advances in bio food packaging - An overview

In recent years, there has been an increase in demand for bioactive techniques in the food packaging industry. Although edible packaging is popular, it has yet to be effectively implemented into the market. Packaging made of plastics and chemicals is widely employed in the market today, posing a threat to the environment and living creatures. This research attempts to show current breakthroughs and progress in the field of biodegradable packaging. When compared to ancient packaging materials, bio-based packaging materials are safer. Sustainable biodegradable packaging materials can be made from edible films, coatings, and other bio food packaging techniques made from various biological resources. This paper discusses the important qualities and advantages of several bio-based packing materials. It is highlighted the advantages of bio-based packaging materials over synthetic packaging materials. It has been debated the importance of employing bio-based packaging to mitigate the environmental risks associated with traditional packaging technologies. Many researchers may be prompted by this study to focus on packaging reformulation options. Thus, we can attain food packing materials by considering customer's economic and sustainability aspects.

Detection of bacteria using antimicrobial polymer derived via ring-opening metathesis (romp) pathway

There is growing interest in the detection of bacteria in consumables, for example, in the food and water sectors. In this study, the aim was to produce a polymer-based bacteria biosensor via ROMP (ring opening metathesis polymerization). In the first part of the study, block and random copolymers were synthesized, and their biocidal activities were tested on the glass surface. Interdigitated electrode arrays coated with the polymers possessing the highest activity were used to screen the affinity towards different bacterial strains by monitoring impedance variations in real-time. The polymer-coated electrode could detect gram-positive and gram-negative bacteria strains at a concentration of 107 cfu/mL. The results show that ROMP-based polymer offers bacterial detection and can be used in developing biosensor devices for efficiently detecting pathogenic bacteria.

Current Trends of Food Analysis, Safety, and Packaging

Food is a basic necessity for life, growth, survival, and maintaining a proper body function. Rising food demand leads both producers and consumers to search for alternative food sources with high nutritional value. However, food products may never be completely safe. The oxidation reaction may alter both the physicochemical and immunological properties of food products. Maillard and caramelization nonenzymatic browning reactions can play a pivotal role in food acceptance through the ways they influence quality factors such as flavor, color, texture, nutritional value, protein functionality, and digestibility. There is a multitude of adulterated foods that portray adverse risks to the human condition. To maintain food safety, the packaging material is used to preserve the quality and freshness of food products. Food safety is jeopardized by plenty of pathogens by the consumption of adulterated food resulting in multiple foodborne illnesses. Though different analytical tools are used in the analysis of food products, yet, adulterated food has repercussions for the community and is a growing issue that adversely impairs human health and well-being. Thus, pathogenic agents' rapid and effective identification is vital for food safety and security to avoid foodborne illness. This review highlights the various analytical techniques used in the analysis of food products, food structure, and quality of food along with chemical reactions in food processing. Moreover, we have also discussed the effect on health due to the consumption of adulterated food and focused on the importance of food safety, including the biodegradable packaging material.

Targeted Gold Nanohybrids Functionalized with Folate-Hydrophobic-Quaternized Pullulan Delivering Camptothecin for Enhancing Hydrophobic Anticancer Drug Efficacy

This study presented a green, facile and efficient approach for a new combination of targeted gold nanohybrids functionalized with folate-hydrophobic-quaternized pullulan delivering hydrophobic camptothecin (CPT-GNHs@FHQ-PUL) to enhance the efficacy, selectivity, and safety of these systems. New formulations of spherical CPT-GNHs@FHQ-PUL obtained by bio-inspired strategy were fully characterized by TEM, EDS, DLS, zeta-potential, UV-vis, XRD, and ATR-FTIR analyses, showing a homogeneous particles size with an average size of approximately 10.97 ± 2.29 nm. CPT was successfully loaded on multifunctional GNHs@FHQ-PUL via intermolecular interactions. Moreover, pH-responsive CPT release from newly formulated-CPT-GNHs@FHQ-PUL exhibited a faster release rate under acidic conditions. The intelligent CPT-GNHs@FHQ-PUL (IC50 = 6.2 μM) displayed a 2.82-time higher cytotoxicity against human lung cancer cells (Chago-k1) than CPT alone (IC50 = 2.2 μM), while simultaneously exhibiting less toxicity toward normal human lung cells (Wi-38). These systems also showed specific uptake by folate receptor-mediated endocytosis, exhibited excellent anticancer activity, induced the death of cells by increasing apoptosis pathway (13.97%), and arrested the cell cycle at the G0-G1 phase. The results of this study showed that the delivery of CPT by smart GNHs@FHQ-PUL systems proved to be a promising strategy for increasing its chemotherapeutic effects.

Harvesting of Antimicrobial Peptides from Insect (Hermetia illucens) and Its Applications in the Food Packaging

About one-third of the total food produced is wasted, rising the concern to adopt proper management. Simultaneously with the increase in population, demand for food is increasing which may lead to scarcity. Adequate packaging is one of the ways to avoid deterioration of food and prevent wastage. In recent years, active packaging has attained interest due to its commendable results in food preservation. Several studies proved that the embodiment of antimicrobial components into the packaging material has the ability to prevent microbial contamination. Antimicrobial peptides (AMP) are newly discovered antimicrobial agents for impregnation into packaging material. Among various sources for AMP, insects have shown great resistivity against a wide spectrum of microorganisms. Insects feed on substances consisting of a varying range of contaminations, which often results in infections. Insects synthesise AMPs to fight such infections and survive in that atmosphere. The disease-causing agents in humans are the same as those found in insects. Hence, AMPs extracted from insects have the potential to fight the microorganisms that act as hazards to human health. This review highlights the harvesting and synthesis of AMPs from Hermetia illucens, which is a promising source for AMP and its applications in the food packaging industry.

Prevention and Treatment of Fungal Skin Infections Using Cationic Polymeric Films

Dermatophytosis is a fungal infection of skin, nails and hair. Treatments can be long and infections are often recurrent, and novel treatments are desirable. Here we tested the use of polymeric films that can be sprayed on the skin for the prevention and treatment of dermatophytosis. The two polymers selected were ABIL T Quat 60 and Eudragit E100, which were tested ex vivo using a porcine skin model, and in vitro using microbiological and microscopy techniques. Acceptability of the polymeric films was tested on the skin of healthy volunteers. The results showed that ABIL and Eudragit films prevented and treated fungal skin infections. Whilst polymer films may provide a physical barrier that prevents fungal colonization, it was shown that both polymers are active antifungals ex vivo and in vitro and have intrinsic antifungal activity. For ABIL, we also established that this polymer binds essential nutrients such as metal ions and sugars, thereby restricting the growth of fungi. When applied to healthy subjects’ skin, the polymeric films neither modified the skin color nor increased trans-epidermal water loss, suggesting a low potential for skin irritation, and the approach was generally found to be acceptable for use by the volunteers. In conclusion, we developed a novel strategy for the potential prevention and treatment of dermatophytosis.

Towards a Bioactive Food Packaging: Poly(Lactic Acid) Surface Functionalized by Chitosan Coating Embedding Clove and Argan Oils

Here we introduce a new method aiming the immobilization of bioactive principles onto polymeric substrates, combining a surface activation and emulsion entrapment approach. Natural products with antimicrobial/antioxidant properties (essential oil from Syzygium aromaticum-clove and vegetal oil from Argania spinosa L-argan) were stabilized in emulsions with chitosan, a natural biodegradable polymer that has antimicrobial activity. The emulsions were laid on poly(lactic acid) (PLA), a synthetic biodegradable plastic from renewable resources, which was previously activated by plasma treatment. Bioactive materials were obtained, with low permeability for oxygen, high radical scavenging activity and strong inhibition of growth for Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli bacteria. Clove oil was better dispersed in a more stable emulsion (no separation after six months) compared with argan oil. This leads to a compact and finely structured coating, with better overall properties. While both clove and argan oils are highly hydrophobic, the coatings showed increased hydrophilicity, especially for argan, due to preferential interactions with different functional groups in chitosan. The PLA films coated with oil-loaded chitosan showed promising results in retarding the food spoilage of meat, and especially cheese. Argan, and in particular, clove oil offered good UV protection, suitable for sterilization purposes. Therefore, using the emulsion stabilization of bioactive principles and immobilization onto plasma activated polymeric surfaces we obtained a bioactive material that combines the physical properties and the biodegradability of PLA with the antibacterial activity of chitosan and the antioxidant function of vegetal oils. This prevents microbial growth and food oxidation and could open new perspectives in the field of food packaging materials.

pH and light-responsive polycaprolactone/curcumin@zif-8 composite films with enhanced antibacterial activity

Food packaging materials, especially biodegradable polymer composites incorporated with natural antimicrobial agents with excellent antibacterial activities, are in high demand and attracted immense attention. Herein, a polycaprolactone/curcumin@zeolitic imidazolate framework-8 (PCL/Cur@ZIF-8) composite film with enhanced antibacterial activity was developed. Curcumin, a natural photosensitizer, was loaded in the highly porous nanocrystals ZIF-8 to improve its poor water solubility and stability. The integral structure of Cur@ZIF-8 was maintained well in the PCL matrix even at the highest loading of 35% (w/w), and all composite films had good light transmittance at 420-430 nm. The PCL/Cur@ZIF-8 composite films responded to the acidic growth environment of bacteria by releasing zinc ions and curcumin molecules. Furthermore, upon blue light irradiation (420-430 nm, 2.2 mW/cm² ), curcumin molecules generated singlet oxygen. With the synergistic effects of zinc ions and singlet oxygen, the composite films exhibited a 99.9% reduction of Escherichia coli and Staphylococcus aureus strains when the amount of Cur@ZIF-8 loading was more than 15% (w/w), as well as a strong anti-adhesion effect on bacteria. Moreover, bacterial resuscitation tests indicated that the composite films exhibited 99.9% reduction in the adhered bacteria population through treatment with photodynamic sterilization. This is the first study presenting that the incorporated curcumin ZIF-8 nanoparticles in the matrix of polymer are pH and light responsive for anti-adhesion of bacteria, which is of great potential application as antibacterial packaging material for the food industry. PRACTICAL APPLICATION: A novel, biodegradable, pH, and light-responsive composite film was developed for antibacterial activity. Natural photosensitizer curcumin was encapsulated in ZIF-8 nanocrystals (Cur@ZIF-8) as the antimicrobial agent. With the synergistic effects of Zn²⁺ and singlet oxygen, the composite film exhibited a 99.9% reduction of Escherichia coli and Staphylococcus aureus strains, and a strong anti-adhesion property toward bacteria. This composite film is of great potential application as an antibacterial packaging material that enhances the shelf life of fruits, meat, and so on.

Antimicrobial Food Packaging with Biodegradable Polymers and Bacteriocins

Innovations in food and drink packaging result mainly from the needs and requirements of consumers, which are influenced by changing global trends. Antimicrobial and active packaging are at the forefront of current research and development for food packaging. One of the few natural polymers on the market with antimicrobial properties is biodegradable and biocompatible chitosan. It is formed as a result of chitin deacetylation. Due to these properties, the production of chitosan alone or a composite film based on chitosan is of great interest to scientists and industrialists from various fields. Chitosan films have the potential to be used as a packaging material to maintain the quality and microbiological safety of food. In addition, chitosan is widely used in antimicrobial films against a wide range of pathogenic and food spoilage microbes. Polylactic acid (PLA) is considered one of the most promising and environmentally friendly polymers due to its physical and chemical properties, including renewable, biodegradability, biocompatibility, and is considered safe (GRAS). There is great interest among scientists in the study of PLA as an alternative food packaging film with improved properties to increase its usability for food packaging applications. The aim of this review article is to draw attention to the existing possibilities of using various components in combination with chitosan, PLA, or bacteriocins to improve the properties of packaging in new food packaging technologies. Consequently, they can be a promising solution to improve the quality, delay the spoilage of packaged food, as well as increase the safety and shelf life of food.

Antimicrobial materials produced by incorporating copper acetate into ethylene-vinyl alcohol copolymer for its use in personal care and cosmetic packaging

Currently, there is a great demand for functional materials with effective pathogen-killing properties. In this research, we describe the use of green technology “reactive extrusion” for the synthesis of potent antimicrobial materials based on Ethylene-vinyl alcohol copolymer (EVOH). Herein, the antimicrobial agent, copper (II) acetate was used without pretreatment and introduced into the EVOH matrices at high temperatures. The thermal reaction of copper (II) acetate within the EVOH matrices and their effect on the thermal and thermomechanical properties of the polymer were investigated in regards to their concentration. The physicochemical, thermal, and rheological features, as well as, metal salt release kinetics were reported. The antimicrobial agent had significant effects on the properties of the matrix. Results showed a reduction in the glass transition temperatures and storage modulus of the materials in response to the incorporation of copper (II) acetate. Finally, the antimicrobial activity of the products was studied and demonstrated a possibility to create antimicrobial materials in a one-step, solvent-free extrusion process.

Thermal and Thermo-Mechanical Properties of Poly(L-lactic Acid) Biocomposites Containing β-Cyclodextrin/d-Limonene Inclusion Complex

Bio-based composites made of poly(L-lactic acid) (PLLA) and β-cyclodextrin/d-limonene inclusion complex (CD-Lim) were prepared by melt extrusion. Encapsulation of volatile d-limonene molecules within β-cyclodextrin cages was proven to be a successful strategy to prevent evaporation during high-temperature processing. However, small amounts of limonene were released upon processing, resulting in the plasticization of the polymeric matrix. Morphological analysis revealed good dispersion of the filler, which acted as a nucleating agent, favoring the growth of PLLA crystals. The composites′ lowered glass transition temperature upon the addition of CD-Lim was also proved by thermomechanical analysis (DMA). Moreover, DMA revealed constant stiffness of modified materials at room temperature, which is crucial in PLLA-based formulations.

The fabrication of a novel film based on polycaprolactone incorporated with chitosan and rutin: potential as an antibacterial carrier for rainbow trout packaging

ABSTRACT

Rutin and chitosan could be utilized in the food industry owing to their antioxidant and antibacterial properties. This study was carried out to fabricate novel films using polycaprolactone (PCL-sole), PCL and chitosan (PCL-CS), PCL and rutin (PCL-R), and PCL, chitosan, and rutin (PCL-CS-R) through electros pinning method. Physical properties, in vitro antibacterial and antioxidant properties of the films, and their antibacterial activity on rainbow trout were further investigated. The PCL-CS, PCL-R, and PCL-CS-R had smaller fiber diameter and film thickness and lower viscosity while they showed higher surface tension, water contact angle, and conductivity and better antibacterial and antioxidant properties compared with PCL-sole film (P < 0.05). The PCL-CS-R film respectively decreased 17.45%, 19.27%, and 18.39% more populations of L. monocytogenes, S. aureus, and E. coli compared to PCL-sole film in the fish samples. Therefore, the PCL-CS-R film can be potentially used in active packaging because of its antioxidant and antibacterial activities.

GRAPHIC ABSTRACT

Recent Developments in Smart Food Packaging Focused on Biobased and Biodegradable Polymers

Food packaging has a crucial function in the modern food industry. New food packaging technologies seek to meet consumers and industrial's demands. Changes related to food production, sale practices and consumers' lifestyles, along with environmental awareness and the advance in new areas of knowledge (such as nanotechnology or biotechnology), act as driving forces to develop smart packages that can extend food shelf-life, keeping and supervising their innocuousness and quality and also taking care of the environment. This review describes the main concepts and types of active and intelligent food packaging, focusing on recent progress and new trends using biodegradable and biobased polymers. Numerous studies show the great possibilities of these materials. Future research needs to focus on some important aspects such as possibilities to scale-up, costs, regulatory aspects, and consumers' acceptance, to make these systems commercially viable.

The Effect of Modified Lysozyme Treatment on the Microflora, Physicochemical and Sensory Characteristics of Pork Packaged in Preservative Gas Atmospheres

The aim of the study was to investigate the effect of modified lysozyme on the microflora, physicochemical and sensory characteristics of pork loin packaged in modified atmospheres and stored at 4 ± 1 °C. Different gas compositions (M1 65:25:10 O2:CO2:N2; M2 50:40:10 O2:CO2:N2; M3 80:20 O2:CO2) were used. The microbiological parameters (APC, Enterobacteriaceae, Pseudomonas spp., lactic acid bacteria), physicochemical indexes (pH, colour) as well as a sensory attribute, i.e., aroma were analysed. Meat samples were tested after five, 12, 19, 23, and 28 days of storage. Changes in the qualities of pork were determined throughout the storage. The proportions of polymeric forms, hydrolytic activity and hydrophobicity were determined in the lysozyme preparation. Modified lysozyme exhibited higher hydrophobicity and lower hydrolytic activity than lysozyme monomer. The colour parameters L* and a* were not considerably affected by the addition of modified lysozyme. The sample with the modified lysozyme was given the highest score for aroma. In comparison with the monomer, the modified lysozyme exhibited greater antibacterial effect, especially against Pseudomonas and Enterobacteriaceae. Microbial growth rates in the sample with modified lysozyme, packaged in an atmosphere with the highest content of CO2 (total plate count 4.59 log CFU/cm2; moulds and yeasts 2.17 log CFU/cm2) were lower than those observed in the sample without lysozyme packed under M1 and M3 (20−25% CO2). The use of an atmosphere with gas composition and modified lysozyme considerably extended the shelf life of pork. The combination of the atmosphere with the highest content of carbon dioxide (50% O2, 40% CO2, 10% N2) and modified lysozyme resulted in the best effect. This strategy extended the shelf-life by more than 20%, as compared with the control sample without lysozyme, packaged in an atmosphere of 50:40:10 O2:CO2:N2.

Green Design of Novel Starch-Based Packaging Materials Sustaining Human and Environmental Health

A critical overview of current approaches to the development of starch-containing packaging, integrating the principles of green chemistry (GC), green technology (GT) and green nanotechnology (GN) with those of green packaging (GP) to produce materials important for both us and the planet is given. First, as a relationship between GP and GC, the benefits of natural bioactive compounds are analyzed and the state-of-the-art is updated in terms of the starch packaging incorporating green chemicals that normally help us to maintain health, are environmentally friendly and are obtained via GC. Newer approaches are identified, such as the incorporation of vitamins or minerals into films and coatings. Second, the relationship between GP and GT is assessed by analyzing the influence on starch films of green physical treatments such as UV, electron beam or gamma irradiation, and plasma; emerging research areas are proposed, such as the use of cold atmospheric plasma for the production of films. Thirdly, the approaches on how GN can be used successfully to improve the mechanical properties and bioactivity of packaging are summarized; current trends are identified, such as a green synthesis of bionanocomposites containing phytosynthesized metal nanoparticles. Last but not least, bioinspiration ideas for the design of the future green packaging containing starch are presented.

Antimicrobial activities of chitosan/titanium dioxide composites as a biological nanolayer for food preservation: A review

Packaging is an integral part of food industry that preserves the properties of food during storage. Food spoilage caused by foodborne microorganisms is a public health problem that imposes a significant burden on the healthcare systems. Moreover, packaging based on artificial and chemical materials such as plastic is destructive to the environment. Chitosan can be categorized as an active food packaging material because of its inherent antimicrobial properties and capacity to carry various active components. Combining chitosan and metallic nanoparticles can be used as a practical approach in antimicrobial packaging systems. This strategy has advantages of thermal stability, barrier properties, antioxidant and antimicrobial packaging. Titanium dioxide is one of these nanoparticles that plays a photocatalytic role by releasing reactive oxygen species, thereby leading to the destruction of microorganisms' cell wall and extension of food shelf life. This review elaborates on the antimicrobial applications of chitosan/titanium dioxide nanoparticles films in food packaging systems.

Inorganic Nanocarriers for Encapsulation of Natural Antimicrobial Compounds for Potential Food Packaging Application: A Comparative Study

Design and development of novel inorganic nanocarriers for encapsulation of natural antimicrobial substances for food packaging applications have received great interest during the last years. Natural nanoclays are the most investigated nanocarriers and recently interest has also grown in the synthetically produced porous silica particles. However, these different carrier matrices have not been compared in terms of their loading capability and subsequent release. In this study, the feasibility of porous silica particles (with different pore structures and/or surface functionalities) and commercially available nanoclays were evaluated as encapsulation matrices. Two well-studied antimicrobial substances, thymol and curcumin, were chosen as volatile and non-volatile model compounds, respectively. The encapsulation efficiency, and the subsequent dispersibility and release, of these substances differed significantly among the nanocarriers. Encapsulation of the volatile compound highly depends on the inner surface area, i.e., the protective pore environment, and an optimal nanocarrier can protect the encapsulated thymol from volatilization. For the non-volatile compound, only the release rate and dispersibility are affected by the pore structure. Further, water-activated release of the volatile compound was demonstrated and exhibited good antimicrobial efficacy in the vapor phase against Staphylococcus aureus. This comparative study can provide a base for selecting the right nanocarrier aimed at a specific food packaging application. No nanocarrier can be considered as a universally applicable one.

High performance compatible thiazole-based polymeric blend cellulose acetate membrane as selective CO2 absorbent and molecular sieve

Green blend membranes comprise of high thermal resistance ortho-linked thiazole-based polyimine (PM-4) including thioether linkage were fabricated in combination of glassy cellulose acetate (CA). The thermal stabilities of PMs were examined using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Morphological aspects and functional groups of the membranes were investigated via field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) analysis respectively. X-ray diffraction (XRD) and mechanical strength were determined as well. The effects of polyimine content, pressure and temperature were studied on CO₂ permeability (P) and selectivity. The pressure changes revealed exponentially increases on CO₂ permeability by plasticization, facilitated transfer and solution-diffusion mechanisms, but decreases on CH₄ and N₂ permeations. Remarkable permeation (P =  3000 Barrer) of CA/PM-4 (1:3 % w/w) and ideal selectivity ratios of CO₂/N₂ = 59, CO₂/CH₄ = 33.7 were obtained at 3 bar and 35 °C versus neat CA membrane.

Development of novel cocrystal-based active food packaging by a Quality by Design approach

A way to reduce food waste is related to the increase of the shelf-life of food as a result of improving the package type. An innovative active food packaging material based on cocrystallization of microbiologically active compounds present in essential oils i.e. carvacrol, thymol and cinnamaldehyde was developed following the Quality by Design principles. The selected active components were used to produce antimicrobial plastic films with solidified active ingredients on their surface characterized by antimicrobial properties against four bacterial strains involved in fruit and vegetable spoilage. The developed packaging prototypes exhibited good antimicrobial activity in vitro providing inhibition percentage of 69 (±15)% by contact and inhibition diameters of 32 (±6) mm in the gas phase, along with a prolonged release of the active components. Finally, the prolonged shelf-life of grape samples up to 7 days at room temperature was demonstrated.

Antifungal Activity of Gelatin-Tapioca Starch Film and Coating Containing Copper Nanoparticles against Colletotrichum gloeosporioides Causing Anthracnose

This study aimed to fabricate a nontoxic coating containing copper nanoparticles (CuNPs) to protect fruits from pathogenic Colletotrichum gloeosporioides causing anthracnose on several tropical fruits. We used a green approach, in which CuNPs were synthesized by reducing CuSO4 with ascorbic acid in the presence of gelatin and glycerol as the capping agents. The formation of CuNPs was confirmed by UV-vis absorption spectra of the reaction mixture, which showed a surface plasmon resonance peak at 578–594 nm. The x-ray diffraction spectrum of the CuNPs indicated the presence of mostly metallic copper with some minor impurities of Cu2O, CuO, and Cu(OH)2. Transmission electron microscopy (TEM) images and dynamic light scattering studies showed that the sizes of 90% of CuNPs were in 100–300 nm range. A 30–50 nm capping layer of gelatin surrounding CuNPs can be observed in the TEM images. Comparing FTIR spectra of the used reagents and CuNPs confirmed the depletion of ascorbic acid, as well as the gelatin layer protecting CuNPs. The synthesized CuNPs showed dose-dependent antifungal activity against C. gloeosporioides with 100% growth inhibition at 200 ppm copper. Gelatinized tapioca starch was then added to the CuNPs solution to obtain a film-forming mixture to produce stand-alone composite films on Petri dishes and coatings on mangoes. C. gloeosporioides could not grow on the surface of nutrient agar in contact with the films containing 245 ppm CuNPs, while they grew normally on control films without CuNPs. For the in vivo antifungal tests on mangoes, both the control and the CuNPs-containing coatings equally inhibit fungal growth, possibly due to the low oxygen permeability of the protein and starch components in the films. This study thus demonstrated the potential applications of composite coatings using biodegradable polymers that contain CuNPs in postharvest protecting fruits from phytopathogenic fungi.

MM, Aldalbahi AK, Thamer BM, Mahmoud YAG, El-Hamshary H. Biocidal Polymers: Synthesis, Characterization and Antimicrobial Activity of Bis-Quaternary Onium Salts of Poly(aspartate-co-succinimide)

Microbial multidrug resistance presents a real problem to human health. Therefore, water-soluble polymers based on poly(aspartate-co-succinimide) were synthesized via reaction of poly(aspartate-co-succinimide) with bis-quaternary ammonium or quaternary salts. The resultant copolymers were characterized by various techniques such as FTIR, TGA, ¹HNMR, ¹³CNMR and elemental microanalysis. Antimicrobial activities of the new onium salts were investigated against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhi, and the fungi; Candida albicans,Aspergillus niger, Cryptococcus neoformans and Aspergillus flavus by agar diffusion method. Antimicrobial activity was studied in terms of inhibition zone diameters, in addition to the estimation of minimal inhibitory concentration (MIC) of the prepared compounds. A. niger and E. coli were the most affected microorganisms among the tested microorganisms with an inhibition zone of 19-21 (mm) in case of biocides, (V) and (VII). The obtained results showed that the quaternary onium salts have higher activity compared to the aspartate copolymer with MIC concentrations of 25 mg/mL for (VII) and (V) and 50 mg/mL for (VI) and (IV).

Novel Biodegradable Starch Film for Food Packaging with Antimicrobial Chicory Root Extract and Phytic Acid as a Cross-Linking Agent

The aim of the study was to obtain and evaluate the properties of biodegradable starch film with the addition of phytic acid (0.05%) as a cross-linking agent and chicory root extract (1-5%) as an antimicrobial agent. To prepare biodegradable film, extracts from chicory root obtained with water or methanol were used. The content of bioactive compounds (sesquiterpene lactones and total polyphenols) was evaluated in chicory extracts. The antibacterial activity of the extracts was tested against Gram-negative bacteria (Pseudomonas fluorescens, Escherichia coli) and Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus) using the microculture method. The extracts acted as bacteriostatic agents, decreasing the growth rate (µ_max), and extending the lag phase (t_lag). The most sensitive bacterium in terms of film bacteriostatic activity was P. fluorescens; all extracts, irrespective of the solvent used, decreased its µ_max value. S. aureus was the least sensitive. The obtained films were tested for their properties as food packaging (color, thickness, permeability, mechanical strength). Phytic acid improved the tensile strength and barrier properties of the films. The antimicrobial activity of the films was studied by the disk diffusion method against Gram-negative (P. fluorescens, E. coli) and Gram-positive (B. subtilis, S. aureus) bacteria, as well as fungi (Candida albicans, Aspergillus niger). The growth-inhibiting activity of each obtained film was observed for all tested microorganisms, and the most beneficial effect was observed for films with the 5% level of added extracts obtained with water. The growth-inhibiting activity for fungi, in particular for the yeast C. albicans, was low.

Monomer conversion, biaxial flexural strength, apatite forming ability of experimental dual-cured and self-adhesive dental composites containing calcium phosphate and nisin

The aim was to develop dual-cured, self-adhesive composites containing monocalcium phosphate monohydrate (MCPM, 8 or 4 wt%) and nisin (6 or 3 wt%) with added adhesive monomer. The effect of additives on monomer conversion (MC), biaxial flexural strength (BFS), dentin shear bond strength (SBS), and surface apatite formation were examined. All experimental composites showed light-activated MC (70-75%) higher than the commercial self-adhesive composite (Vertise Flow; VF, 65%). The additives reduced BFS of the composites from 217 to 133 MPa. SBS of the experimental composites (2-6 MPa) was lower than that of VF (12 MPa). Rising MCPM level enabled apatite-like crystals precipitated on the surface of composites after immersion in simulated body fluid for 4 weeks. The additives showed negligible effect on MC and SBS. Rising level of additives reduced strength of the composites but the values were still higher than that required by the standard.

Fabrication of Functional Bioelastomer for Food Packaging from Aronia (Aronia melanocarpa) Juice Processing By-Products

Carbon-neutral and eco-friendly biomass-based processes are recognized as a frontier technology for sustainable development. In particular, biopolymers are expected to replace petrochemical-based films that are widely used in food packaging. In this study, the fabrication conditions of functional (antioxidant and antibacterial) bioelastomers were investigated using by-products from the juice processing (experimental group) and freeze-dried whole fruit (control group). Bioelastomer was fabricated by a casting method in which polydimethylsiloxane (PDMS) was mixed with 25 or 50 wt% aronia powder (juice processing by-products and freeze-dried whole fruit). The mechanical properties of the bioelastomers were measured based on tensile strength and Young's modulus. When the mixture contained 50 wt% aronia powder, the strength was not appropriate for the intended purpose. Next, the surface and chemical properties of the bioelastomer were analyzed; the addition of aronia powder did not significantly change these properties when compared to PDMS film (no aronia powder). However, the addition of aronia powder had a significant effect on antioxidant and antimicrobial activities and showed higher activity with 50 wt% than with 25 wt%. In particular, bioelastomers fabricated from aronia juice processing by-products exhibited approximately 1.4-fold lower and 1.5-fold higher antioxidant and antimicrobial activities, respectively, than the control group (bioelastomers fabricated from freeze-dried aronia powder).

Influence of the Ultrasonic Treatment on the Properties of Polybutylene Adipate Terephthalate, Modified by Antimicrobial Additive

Particular attention is paid to biodegradable materials from the environmental point of view and antimicrobial materials that ensure the microbiological safety of packaged products. The aim of the work was to study the properties of the composition, based on biodegradable polybutylene adipate terephthalate (PBAT) and the antimicrobial additive-birch bark extract (BBE). Test samples of materials were obtained on the laboratory extruder by extrusion with ultrasonic treatment of the melt. The concentration of the antimicrobial additive in the polymer matrix was 1 wt %. A complex research was carried out to study the structural, physico-mechanical characteristics, antimicrobial properties and biodegradability of the modified PBAT. Comparative assessment of the physico-mechanical characteristics of samples based on PBAT showed that the strength and elongation at break indices slightly decrease when the ultrasonic treatment of the melt is introduced. It was found out, that the antimicrobial additive in the composition of the polymer matrix at the concentration of 1 wt % has a static effect on the development of microorganisms on the surface of the studied modified films. Studies of the biodegradability of modified PBAT by composting for 4 months have shown that the decomposition period of modified materials increased, compared to pure PBAT. The developed modified polymer material can be recommended as an alternative replacement for materials based on polyethylene for food packaging.

Biodegradable Antimicrobial Food Packaging: Trends and Perspectives

This review presents a perspective on the research trends and solutions from recent years in the domain of antimicrobial packaging materials. The antibacterial, antifungal, and antioxidant activities can be induced by the main polymer used for packaging or by addition of various components from natural agents (bacteriocins, essential oils, natural extracts, etc.) to synthetic agents, both organic and inorganic (Ag, ZnO, TiO2 nanoparticles, synthetic antibiotics etc.). The general trend for the packaging evolution is from the inert and polluting plastic waste to the antimicrobial active, biodegradable or edible, biopolymer film packaging. Like in many domains this transition is an evolution rather than a revolution, and changes are coming in small steps. Changing the public perception and industry focus on the antimicrobial packaging solutions will enhance the shelf life and provide healthier food, thus diminishing the waste of agricultural resources, but will also reduce the plastic pollution generated by humankind as most new polymers used for packaging are from renewable sources and are biodegradable. Polysaccharides (like chitosan, cellulose and derivatives, starch etc.), lipids and proteins (from vegetal or animal origin), and some other specific biopolymers (like polylactic acid or polyvinyl alcohol) have been used as single component or in blends to obtain antimicrobial packaging materials. Where the package's antimicrobial and antioxidant activities need a larger spectrum or a boost, certain active substances are embedded, encapsulated, coated, grafted into or onto the polymeric film. This review tries to cover the latest updates on the antimicrobial packaging, edible or not, using as support traditional and new polymers, with emphasis on natural compounds.