Active Packaging Applications Research Articles

Active biopackaging produced from by-products and waste from food and marine industries.

The agro‐food industry cannot today do without packaging to preserve and above all market its products. Plastic materials coming mainly from petrochemicals have taken a predominant place in the food packaging sector. They have become indispensable in many sectors, from fresh to frozen products, from meat and dairy products to fruit and vegetables or almost‐ready meals. Plastics are cheap, their lightness reduces transport costs, and their convenience is fundamental for out‐of‐home catering. However, plastics pose serious end‐of‐life issues. The development of materials that are more respectful of the consumer and the environment has become a major issue. In addition, the agro‐food industries generate significant quantities of waste or by‐products that are poorly or not at all recovered. However, these contain constituents that can be extracted or transformed to be compatible with packaging uses. Many molecules from waste materials are of particular interest for the development of active packaging such as biopolymers, bioactive agents, inorganic compounds, fibers, or nano‐ and micro‐objects. Providing bioactive functions such as antioxidants or antimicrobials can extend the shelf life of food while reducing the sophistication of plastic materials and thus improving their recycling. This article summarizes the main materials and constituents that can be recovered from waste and illustrates through several examples what could be the applications of such new, sustainable, and active packaging.

PLLA‐ZIF‐8 metal organic framework composites for potential use in food applications: Production, characterization and migration studies

PLLA‐15% ZIF‐8 MOF composites were fabricated by melt compounding followed by injection molding for active packaging applications. The injection‐molded discs were then converted into films by compression molding. The samples were morphological and thermally characterized. Migration studies using Atomic Absorption Spectrometry were conducted on the successful produced PLLA and PLLA‐15% MOF films incubated at 40°C for 240 h with two simulants, Simulant A: aqueous and acidic foods with 10% ethanol, and Simulant B: low and high alcoholic foods with 50% ethanol as per the U.S. Food and Drug Administration guidelines for packaging application testing. After 240 h Zn2+ ion concentrations in Simulants A and B were 354 and 166 mg L−1, respectively. Higher Zn2+ ion migration observed in Simulant A can be ascribed to the decomposition of the ZIF‐8 MOF under acidic environment. Thermo‐gravimetric studies indicated that the thermal stability of PLLA dropped from 338°C to 207°C with the addition of ZIF‐8 MOF, which may be credited to the catalytic depolymerization effect of the MOF. Due to high migration, the studied composite films are not suitable for direct food contact applications in their present form. Future work must be directed to explore how to engineer these composites for food contact applications.

Development of anacardic acid incorporated biopolymeric film for active packaging applications

Biodegradable films with functional characteristics are finding several applications in the active packaging of foods and fresh-cut horticultural produce in particular, as effective alternatives to single-use plastics. In this study, anacardic acid (AA) was extracted from cashew nut shell liquid oil (CNSL) and characterized using GC–MS and HPLC. Further, the extract showed anti-microbial activity against foodborne pathogens such as Escherichia coli, Listeria monocytogenes, Streptococcus faecalis, Salmonella typhi, and Shigella boydii, apart from potent anti-oxidant behavior. With the hypothesis to exploit its food preservation capabilities, packaging films of AA-chitosan blends were prepared; these showed remarkable anti-browning effects on fresh-cut apple slices, superior to chitosan alone. The physical properties of these films were evaluated and the developed film showed around 60 % biodegradability in 30 days. This study highlights a unique application scope for underutilized CNSL.

Physicochemical properties of chitosan/ graphene oxide composite films and their effects on storage stability of palm-oil based margarine

This study investigated the application of active packaging from chitosan (CS) incorporated with graphene oxide (GO) to maintain the quality and extend the storage life of palm-oil based margarine. Composite films containing various concentrations of CS (1.5 and 2.0%w/v) and GO (0, 0.5, 1.0, and 2.0%w/w CS) were produced using the solution casting method and were characterized regarding their mechanical, barrier, and antioxidant properties. For both concentrations of CS, the composite films with 2.0% GO exhibited significantly (p < 0.05) lower water vapor permeability and oxygen permeability by ~43 and ~55%, respectively. The transmittance of UV light was virtually undetectable in CSGO composites. In addition, the radical scavenging activity increased (p < 0.05) with the increasing GO concentration, as demonstrated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The changes in the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) of the margarine samples were monitored for 30 d at 4 °C. The margarine sample that was wrapped with the CS1.5 GO2.0 film sample showed lower (p < 0.05) PV and TBARS values in comparison to the samples wrapped with CS1.5 and low-density polyethylene (LDPE) films. In conclusion, the CSGO composite film in this study shows great potential as an antioxidant food packaging material.

Plasma-treated polyethylene coated with polysaccharide and protein containing cinnamaldehyde for active packaging films and applications on tilapia (Orechromis niloticus) fillet preservation

This study aimed to develop an antimicrobial active packaging using carboxymethyl cellulose (CMC) or collagen (COL) as carriers of cinnamaldehyde (CNMA) coating on plasma-treated low density polyethylene (LDPE) for application on tilapia fillet packaging. COL carriers exhibited stronger antimicrobial and antioxidant activities than no carrier and CMC. The films also showed good physical and mechanical properties after coating. The results on tilapia preservation analysis showed that the COL with 6% CNMA slowed the total plate count and growth of Vibrio parahaemolyticus by about 1.82 log colony-forming units (CFU)/g and 1.76 log CFU/g compared to the control at day 14. All active films were better than Control in delaying the production of volatile basic nitrogen and thiobarbituric acid during storage whilst simultaneously maintaining organoleptic properties. Based on results, the antimicrobial active films significantly prolonged the shelf life of tilapia fillets to 3 days compared with the Control group. The COL with 6% CNMA may potentially play an effective role in maintaining and preserving the microbial qualities of tilapia fillets.

Characterization of Ecofriendly Poly (Vinyl Alcohol) and Green Banana Peel Filler (GBPF) Reinforced Bio-Films

With an intention to replace the synthetic non-biodegradable films in packaging applications, the polyvinyl alcohol (PVA) blended with green banana peel filler (GBPF), the biodegradable films were prepared by solution casting method with varying the concentrations of GBPF (5–25 wt%) in PVA matrix. The bio films were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermo gravimetric analysis, transmissibility, FESEM, tensile test, film solubility and water absorption, water vapour transmission (WVT), soil burial test. Based on results obtained, the changes evidenced in the FTIR spectrum of this PVA/GBPF biofilms suggest that strong hydrogen bonding is taking place due to interfacial exchanges of GBPF in PVA matrix. The XRD results showed that crystallinity of bio films are greater than PVA. Thermo gravimetric analyses predicted that PVA/GBPF bio films are thermally stable up to 300 °C. The light is 45% for transmittance in the visible light region for the PVA/GBPF (25 wt%) bio film. The FESEM micrographs of biofilms palpable that formation of good physical interaction and compatibility between polymer matrix and GBPF up to 20 wt% of GBPF in PVA Matrix. FESEM results also confirmed that higher loading of GBPF (25 wt%) in PVA matrix, observed voids and agglomerations in film surface. The PVA/GBPF bio films with 20% of GBPF gave the highest tensile strength and young’s modulus 44.5 MPa and 66.7 GPA respectively compared to other samples. The elongation at break decreases with increases the GBPF in PVA Matrix up to 20 wt%.The slight decrease in mechanical properties perceived due to higher loading of GBPF (25 wt%) with PVA matrix. The solubility, water absorption and WVT of the PVA/GBPF bio films increased upon increasing the GBPF content. The biodegradation test results discovered that he highest weight loss at 42.3% (25 wt% of GBPF) probably due to the hydrophilic nature of GBPF in PVA matrix. On the whole, the present investigation confirmed that the PVA/GBPF bio films potential for possible utilization in active packaging applications attributable to its better mechanical, thermal, optical, water absorption and biodegradation properties.

Development of Poly(L-Lactic Acid)/Chitosan/Basil Oil Active Packaging Films via a Melt-Extrusion Process Using Novel Chitosan/Basil Oil Blends

Following the global trend toward a cyclic economy, the development of a fully biodegradable active packaging film is the target of this work. An innovative process to improve the mechanical, antioxidant, and barrier properties of Poly(L-Lactic Acid)/Chitosan films is presented using essential basil oil extract. A Chitosan/Basil oil blend was prepared via a green evaporation/adsorption method as a precursor for the development of the Poly(L-Lactic Acid)/Chitosan/Basil Oil active packaging film. This Chitosan/Basil Oil blend was incorporated directly in the Poly(L-Lactic Acid) matrix with various concentrations. Modification of the chitosan with the Basil Oil improves the blending with the Poly(L-Lactic Acid) matrix via a melt-extrusion process. The obtained Poly(L-Lactic Acid)/Chitosan/Basil Oil composite films exhibited advanced food packaging properties compared to those of the Poly(L-Lactic Acid)/Chitosan films without Basil Oil addition. The films with 5%wt and 10%wt Chitosan/Basil Oil loadings exhibited better thermal, mechanical, and barrier behavior and significant antioxidant activity. Thus, PLLA/CS/BO5 and PLLA/CS/BO10 are the most promising films to potentially be used for active packaging applications.

Melt-Processed Bioactive EVOH Films Incorporated with Ferulic Acid.

In this work, antimicrobial and antioxidant films based on ethylene vinyl alcohol (EVOH) copolymer containing low amounts of ferulic acid (FA) were successfully developed by melt extrusion. Optically transparent films were obtained, and the presence of FA provided some UV blocking effect. The characterization of the thermal and barrier properties of the developed films showed that the addition of FA improved the thermal stability, decreased the glass transition temperature (Tg) and increased the water vapor and oxygen transmission rates when ferulic acid was loaded above 0.5 wt.%, associated with its plasticizing effect. Mechanical characterization confirmed the plasticizing effect by an increase in the elongation at break values while no significant differences were observed in Young’s modulus and tensile strength. Significant antioxidant activity of all active films exposed to two food simulants, 10% ethanol and 95% ethanol, was also confirmed using the 2,2-diphenyl-1-pricylhydrazyl (DPPH) free radical scavenging method, indicating that FA conserved its well-known antioxidant properties after melt-processing. Finally, EVOH-FA samples presented antibacterial activity in vitro against Escherichia coli and Staphylococcus aureus, thus showing the potential of ferulic acid as bioactive compound to be used in extrusion processing for active packaging applications.

Ultrasound in the deproteinization process for chitin and chitosan production

Recently, chitin and chitosan are widely investigated for food preservation and active packaging applications. Chemical, as well as biological methods, are usually adopted for the production of these biopolymers. In this study, modification to a chemical method of chitin synthesis from shrimp shells has been proposed through the application of high-frequency ultrasound. The impact of sonication time on the deproteinization step of chitin and chitosan preparation was examined. The chemical identities of chitin and chitosan were verified using infrared spectroscopy. The influence of ultrasound on the deacetylation degree, molecular weight and particle size of the biopolymer products was analysed. The microscopic characteristics, crystallinity and the colour characteristics of the as-obtained biopolymers were investigated. Application of ultrasound for the production of biopolymers reduced the protein content as well as the particle size of chitin. Chitosan of high deacetylation degree and medium molecular weight was produced through ultrasound assistance. Finally, the as-derived chitosan was applied for beef preservation. High values of luminosity, chromatid and chrome were noted for the beef samples preserved using chitosan films, which were obtained by employing biopolymer subjected to sonication for 15, 25 and 40 min. Notably; these characteristics were maintained even after ten days of packaging. The molecular weight of these samples are 73.61 KDa, 86.82 KDa and 55.66 KDa, while the deacetylation degree are 80.60%, 92.86% and 94.03%, respectively; in the same order, the particle size of chitosan are 35.70 μm, 25.51 μm and 20.10 μm.

Enhancing barrier properties of biodegradable film by reinforcing with 2D heterostructure

Flexible polymeric films are regularly used as packaging materials, but the key challenge is to improve the barrier properties in order to maintain freshness of the food. In this report, we have developed a 2D/2D g-C3N4@CuSe heterostructure based biodegradable film with active intriguing properties, which can hold high potential for intelligent packaging. Excellent barrier properties (1.57 times enhancement) and exceptional mechanical properties (>2 compared to pristine form) of the film have been achieved due to reinforcement of layered structure within the polymer matrix attributing torturous path in gas/water penetration. Further, optimized properties of the developed 2D/2D heterostructure film help in minimizing the defects that promote permeation, resulting in active and outstanding barrier performance which can be used to cover varied types of food packaging. The developed film exhibits integrated functional properties with prominent antimicrobial properties against foodborne pathogens and easy biodegradability to serve as a potential candidate for active sustainable packaging applications.

Structure and properties of edible packaging film prepared by soy protein isolate-eggshell membrane conjugates loaded with Eugenol

Abstract In this study, we reported a facile and economical strategy for producing a functional protein-based composite film that was based on soybean protein isolate (SPI), eggshell membrane (ESM) and eugenol (Eu). The composite films were also characterized by mechanical, water vapor permeability (WVP), UV barrier, water resistance, hydrophobicity, antioxidant and antimicrobial activity. The results suggested the appropriate content of ESM could significantly enhance the mechanical, barrier, water resistance and hydrophobicity performances of the film. The addition of Eu into the SPI/ESM film could improve not only these properties, but also antimicrobial and antioxidant properties. The intermolecular interaction between SPI, ESM and Eu was mainly hydrogen bond confirmed by the Fourier-transform infrared spectroscopy (FTIR). The scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicated a good compatibility existed between SPI and ESM, and the Eu could be well emulsified and dispersed into the SPI/ESM film matrices network. Such edible films carried potentially developed in active packaging applications.

Curcumin Incorporated Poly(Butylene Adipate-co-Terephthalate) Film with Improved Water Vapor Barrier and Antioxidant Properties.

Curcumin incorporated poly(butylene adipate-co-terephthalate) (PBAT) based film was fabricated. Curcumin has uniformly distributed in the PBAT matrix to form a bright yellow PBAT/curcumin film. The PBAT/curcumin film has slightly reduced tensile strength and flexibility than the neat PBAT film, while the thermal stability of the film has not changed significantly. The blending of curcumin significantly decreased the water vapor permeability of the PBAT film. Additionally, the PBAT/curcumin film showed potent antioxidant activity with some antimicrobial activity. The PBAT/curcumin films with improved water vapor barrier and additional functions can be used for active packaging applications.

Activated release of ethyl formate vapor from its precursor encapsulated in ethyl Cellulose/Poly(Ethylene oxide) electrospun nonwovens intended for active packaging of fresh produce

Ethyl formate (EF) is a naturally occurring insecticidal and antimicrobial volatile compound promising as an alternative to synthetic fumigants. In this work, an EF precursor (EFP) was encapsulated in free-surface electrospun ethylcellulose/poly (ethylene oxide) (EC-PEO) nonwovens and the release of EF from the precursor was evaluated using gas chromatography. The effect of EFP (up to 100% w/w, polymer content basis) on EC-PEO solution parameters and fiber morphology was studied. Scanning electron microscopy revealed that EFP particles were entrapped within the electrospun EC-PEO fibers. Fourier transform infrared spectroscopy did not reveal any specific interaction between EFP and the polymers in the nonwovens. When exposed to 0.1 N citric acid (CA) solution for 2 h at 25 °C, the nonwoven loaded with 10% EFP (w/w) released 0.037 mg EF/mg nonwoven (96% of the theoretical release). The EF release decreased significantly (p < 0.05) with decreasing either the CA concentration or the temperature. Preliminary studies showed that the release of EF from the EFP-loaded nonwovens delayed the growth of spoilage microorganisms on strawberries for up to 10 days at 5 °C, suggesting the feasibility of the EFP-loaded nonwoven for active packaging applications.

Application of Active Packaging in Refrigerated Rainbow Trout (Oncorhynchus mykiss) Fillets Treated with UV-C Radiation

This study investigated the effects of oxygen-scavenger packaging and UV-C radiation at two doses, alone or in combination, on lipid oxidation (malondialdehyde levels), protein oxidation (carbonyl content), instrumental color and texture parameters in rainbow trout fillets stored at 4 ± 1 °C for 9 days. The treatments were AP (air packaging), OSP (oxygen-scavenger packaging), AUV1 (air packaging + UV-C at 0.102 J/cm2), OSUV1 (oxygen-scavenger packaging + UV-C at 0.102 J/cm2), AUV3 (air packaging + UV-C at 0.301 J/cm2), and OSUV3 (oxygen-scavenger packaging + UV-C at 0.301 J/cm2). Lipid oxidation, protein oxidation, lightness and yellowness increased, while redness, hardness and chewiness decreased during storage in all treatments (p &lt; 0.05). OSP, OSUV1 and OSUV3 exhibited lower yellowness, total color difference (ΔE), lipid and protein oxidation, and higher redness, hardness and chewiness than air packaging (AP; p &lt; 0.05), being similar to each other concerning these parameters throughout storage (p &gt; 0.05). AUV3 showed higher lipid oxidation, protein oxidation, yellowness, ΔE, and lower redness, hardness and chewiness followed by AUV1 than AP (p &lt; 0.05). UV-C at these doses was not adequate for refrigerated trout fillets by inducing oxidative degradation. O2 scavenger was effective in preventing the adverse effects from storage period and UV-C, independently of the dose, and could be a simple and powerful alternative to make feasible the industrial application of UV-C at 0.102 and 0.301 J/cm2 in refrigerated rainbow trout fillets, which has proven antimicrobial effect and it is a promising non-thermal technology for the fish production chain.

Bio-based films from wheat bran feruloylated arabinoxylan: Effect of extraction technique, acetylation and feruloylation

This study demonstrates the potential of feruloylated arabinoxylan (AX) from wheat bran for the preparation of bioactive barrier films with antioxidant properties. We have comprehensively evaluated the influence of the structural features and chemical acetylation of feruloylated AX extracted by subcritical water on their film properties, in comparison with alkaline extracted AX and a reference wheat endosperm AX. The degree of substitution (DS) of AX had a large influence on film formation, higher DS yielded better thermal and mechanical properties. The barrier properties of AX films were significantly enhanced by external plasticization by sorbitol. Chemical acetylation significantly improved the thermal stability but not the mechanical or barrier properties of the films. The presence of bound ferulic acid in feruloylated AX films resulted in higher antioxidant activity compared to external addition of free ferulic acid, which demonstrates their potential use in active packaging applications for the preservation of oxygen-sensitive foodstuff.

Study of bioactive volatile compounds from different parts of Pistacia lentiscus L. extracts and their antioxidant and antibacterial activities for new active packaging application

Macerates of fruits and leaves of Pistacia lentiscus L. were prepared and analysed with the aim of applying them for active packaging. The profile of forty-four different bioactive volatile compounds was obtained by means of gas chromatography-mass spectrometry and solid-phase microextraction gas chromatography-mass spectrometry. Antioxidant capacity was evaluated by three different methods (2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid and reducing power) which confirmed stronger antioxidant properties in case of leaves macerate. Total phenolic and flavonoids content was determined and showed that macerate leaves presented 15 times more phenolic compounds and 20 times more flavonoids than macerate fruit. Moreover, the analysis of antimicrobial properties of macerate leaves in comparison with macerate fruits revealed very strong antimicrobial properties. Finally, macerate leaves extract was incorporated in an adhesive and a new active multilayer packaging was designed, and its antioxidant capacity as free radical scavenger was confirmed by a method based on in situ hydroxyl radicals generator.

Active packaging applications in fresh chicken meat

Tavuk eti yüksek protein ve nem içeriği nedeniyle hem mikrobiyal hem de biyokimyasal bozulmalara oldukça açık olmasından dolayı raf ömrü kısa olan bir gıdadır. Ayrıca gerek gıdanın doğası gerek işleme koşulları nedeniyle patojen mikroorganizmalarla kontamine olma ihtimalinden dolayı taze tavuk etinin güvenilir bir şekilde üretimini arttırmak ve son tüketiciye ulaşana kadar israf olmasını önlemek amacıyla mikrobiyal güvenilirliğini sağlamak oldukça önemlidir. Taze tavuk etlerinde koruyucu katkı maddeleri ilavesi, ısıl işlem uygulamaları ve/veya dondurma vb. gıda muhafaza yöntemleri kullanılmadığından üründe gerçekleşebilecek biyokimyasal değişimler ve mikrobiyal bozulmaları önlemek için ambalajlama teknolojilerinden yararlanılması işlenmiş gıda ürünlerine göre daha da önem kazanmaktadır. Yenilikçi ambalajlama teknolojileri ile taze tavuk etlerinin kalitesi arttırılıp raf ömrü uzatılabilir ve böylece güvenilirliği de daha iyi sağlanabilir. Bu bağlamda aktif ambalajlama teknolojilerinden yararlanılabilir. Bu amaçla ambalaj malzemesine ya da ambalaj ortamına eklenen antimikrobiyal maddeler, antioksidan maddeler, CO2, etanoL vs. gibi aktif maddelerin etkisiyle gıdanın özellikleri ambalajlandıktan sonra da iyi bir şekilde muhafaza edilebilmektedir. Son yıllarda taze tavuk etlerinin aktif ambalajlama teknolojisi ile ilgili olarak yapılan çalışmalarda; antimikrobiyal ya da antioksidan özelliklerde esansiyel yağlar ile doğal bitki ya da gıda sanayii atıklarından elde edilen ekstraktlar kullanılarak hazırlanan sentetik ve/veya biyobozunur polimerler kullanılmaya başlanmıştır. Bu teknoloji ile ambalajlanmış taze tavuk etlerinde bozulma yapan mikroorganizmaların üreme hızlarının yavaşlatıldığı, patojen mikroorganizmaların üremesinin engellendiği ve/veya lipid oksidasyon hızının azaltıldığına yönelik sonuçlar bulunmaktadır. Bu derleme makalesinde aktif ambalajlama uygulamalarının son yıllarda gerçekleştirilen bilimsel çalışmalar temelinde taze tavuk etlerinin kalitesi, güvenilirliği ve raf ömrü açısından etkileri incelenmiştir.

Preparation and characterization of polyaniline/sodium alginate-doped TiO2 nanoparticles with promising mechanical and electrical properties and antimicrobial activity for food packaging applications

Polymer nanocomposite (PNC) films based on sodium alginate and polyaniline (SA/PANi) and TiO2 as nanoceramic were synthesized by solution casting method. XRD displayed that the average size crystalline of the TiO2 NPs is 19 nm, and the amorphuos degree of the SA/PANi blend decreased due to the addition of TiO2 NPs. The interaction between the TiO2 NPs and the SA/PANi blend was confirmed by FT-IR spectroscopy, due to vibrational changes that occurred after the addition of TiO2 dopant in the polymer blend. The UV–Visible spectrum was used to calculate optical energy band gaps (direct and indirect). Both of the Egdi and Egind were reduced with the rise in TiO2 content. Thermogravimetric showed that the thermal stability of the nanocomposite was higher than the pure SA/PANi. With the increase in TiO2 NPs concentrations and frequency, the electrical properties such as dielectric and ac conductivity of pure blend improved and displayed maximum electrical properties (dielectric and conductivity) at 1 wt% loading. Additionally, the doping of TiO2 NPs in the polymer matrix proved that the nanocomposites exhibited excellent antimicrobial activity against all the bacteria taken for the test. It is obvious from the results that the nanocomposites have the potential for use in active packaging applications.

Efficient Gas Barrier and Antibacterial Properties of Poly(lactic acid) Nanocomposites: Functionalization with Phytic Acid-Cu(II) Loaded Layered Clay.

Poly(lactic acid) (PLA) represents one of the most promising and attractive bio-based polymers for green packaging. However, toughness, gas barrier and antibacterial properties of pure PLA films cannot compete with those of traditional petroleum-based active packaging plastics. To fill this gap, utilization of excellent chelating properties of phytic acid (PA), functionalized layered double hydroxides (LDHs@PA-Cu(II)) was firstly synthetized via facile deposition and chelation of one-step assembled PA-Cu(II) coordination compounds on the surface of layered clay. Furthermore, LDHs@PA-Cu(II)/PLA nanocomposites were prepared by blending LDHs@PA-Cu(II) and pure PLA via solution casting evaporation process. After adding only 1 wt % LDHs@PA-Cu(II), elongation at break and tensile strength increase by 53.0% and 18.9%, respectively, and the oxygen relative permeability decreases by 28.0%. Due to the strong interface interaction and heterogenous nucleation, the reinforcement effect of LDHs@PA-Cu(II) at low loadings is remarkable. Meanwhile, owing to the antibacterial activity of PA-Cu(II) coatings, the antibacterial rate (against Escherichia coli) of LDHs@PA-Cu(II) exceeds 99.99%. Furthermore, the corresponding LDHs@PA-Cu(II)/PLA nanocomposites also show outstanding antibacterial properties, which will be a promising candidate for active packaging application.

Plasticized poly(lactic acid) reinforced with antioxidant covalent organic frameworks (COFs) as novel nanofillers designed for non-migrating active packaging applications

A 2D Covalent Organic Framework (named [HC≡C]0.5-TPB-DMTP-COF) was synthesized and post synthetically functionalized with dopamine via Copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction (COFDOPA) to obtain 2D nanoparticles with antioxidant activity. COFDOPA nanoparticles were exfoliated into nanosheets (COFDOPA-e) and incorporated into plasticized poly(lactic acid) (PLA) matrix with 15 wt% of acetyl trybutyl citrate (ATBC) to develop non-migratory sustainable packaging. The effect of COFDOPA and exfoliated COFDOPA-e (in 0.5, 1 and 3 wt%) on the structural, thermal and mechanical properties of PLA-ATBC was studied. The bionanocomposites loaded with low amounts of COFDOPA-e (0.5 wt% and 1 wt%) resulted optically transparent and showed good interfacial adhesion, increased crystallinity, thermal and mechanical performance. Moreover, the overall migration level assayed in a fatty food simulant was below the migration limits required for food packaging materials and showed effective antioxidant activity. Thus, these bionanocomposites show great potential as non-migration antioxidant materials with interest in the sustainable food packaging field.