Biopolymer hybrid materials: Development, characterization, and food packaging applications

Polysaccharide- and protein-based edible films combined with microwave technology for meat preservation

To reduce food-borne bacterial infection caused by food spoilage, developing highly efficient food packing film is still an urgent need for food preservation. Herein, microwave-assisted antibacterial nanocomposite films CaO2@PVP/EA/CMC-Na (CP/EC) were synthesized using waste eggshell as precursor, egg albumen (EA) and sodium carboxymethylcellulose (CMCNa) as matrix by casting method. The size of CaO2@PVP (CP) nanoparticles with monodisperse spherical structures was 100-240 nm. When microwave and CP nanoparticles (0.05 mg/mL) were treated for 5 min, the mortality of E. coli and S. aureus could reach >97 %. Under microwave irradiation (6 min), the bactericidal rate of 2.5 % CP/EC film against E. coli and S. aureus reached 98.6 % and 97.2 %, respectively. After adding CP nanoparticles, the highest tensile strength (TS) and elongation at break (EB) of CP/EC film reached 19.59 MPa and 583.43 %, respectively. At 18 °C, the proliferation of bacterial colonies on meat can be significantly inhibited by 2.5 % CP/EC film. Detailed characterization showed that the excellent meat preservation activity was due to the synergistic effect of dynamic effect generated by ROS and thermal effect of microwave. This study provides a promising approach for the packaging application of polysaccharide- and protein-based biomass nanocomposite antibacterial edible films.

Pedalium murex plant-based bioplasticizer reinforced polylactic acid films: A promising approach for biodegradable fruit packaging applications

The most likely materials for use in packaging are plastics. A lot of synthetic polymers are harming the environment. A plasticizer is required for all polymers to improve their characteristics and workability. The plasticizers come in liquid form and are also derived from fossil fuels, which are harmful to the environment. Producing functional and affordable biopolymer for packaging applications is a difficult task nowadays. The preparation of biofilm for packaging using biopolymer and bioplasticizer is the main aim of this work. The biopolymer poly L-lactic acid (PLA) is used, and the bio plasticizer is extracted from Pedalium murex plant. Chemical and mechanical methods are used to extract the plasticizer. Plasticization of polylactic acid biopolymer was done using the extracted plasticizer at additions of 1 %, 2 %, 3 %, 4 %, and 5 %. FT-IR spectroscopy, X-ray diffraction spectroscopy, and surface roughness values are used to characterise the prepared biofilms. Scanning electron spectroscopy pictures are utilised to evaluate the morphological orientation of the biofilms. Strawberries packed with biofilms are used to evaluate the barrier properties of biofilms using UV spectroscopy analysis. Thermal degradation behaviour is investigated using thermo gravimetric analysis. We examined the mechanical characteristics, such as tensile strength, elongation modulus, and elongation break percentage. The plasticizing effect of the plasticizer raises the elongation break percentage while decreasing the tensile strength and modulus. For 2 % plasticizer addition the elongation break increases and the tensile not much affected. To demonstrate biodegradability and microbial resistance, the soil degradation behaviour and antimicrobial activities were examined.

Effect of Drying Conditions and Jojoba Oil Incorporation on the Selected Physical Properties of Hydrogel Whey Protein-Based Edible Films

Edible hydrogel coatings or films in comparison to conventional food packaging materials are characterized as thin layers obtained from biopolymers that can be applied or enveloped onto the surface of food products. The use of lipid-containing hydrogel packaging materials, primarily as edible protective coatings for food applications, is recognized for their excellent barrier capacity against water vapor during storage. With the high brittleness of waxes and the oxidation of different fats or oils, highly stable agents are desirable. Jojoba oil obtained from the jojoba shrub is an ester of long-chain fatty acids and monovalent, long-chain alcohols, which contains natural oxidants α, β, and δ tocopherols; therefore, it is resistant to oxidation and shows high thermal stability. The production of hydrogel films and coatings involves solvent evaporation, which may occur in ambient or controlled drying conditions. The study aimed to determine the effect of drying conditions (temperature from 20 to 70 °C and relative humidity from 30 to 70%) and jojoba oil addition at the concentrations of 0, 0.5, 1.0, 1.5, and 2.0% on the selected physical properties of hydrogel edible films based on whey protein isolate. Homogenization resulted in stable, film-forming emulsions with bimodal lipid droplet distribution and a particle size close to 3 and 45 µm. When higher drying temperatures were used, the drying time was much shorter (minimum 2 h for temperature of 70 °C and relative humidity of 30%) and a more compact structure, lower water content (12.00-13.68%), and better mechanical resistance (3.48-3.93 MPa) of hydrogel whey protein films were observed. The optimal conditions for drying hydrogel whey protein films are a temperature of 50 °C and an air humidity of 30% over 3 h. Increasing the content of jojoba oil caused noticeable color changes (total color difference increased from 2.00 to 2.43 at 20 °C and from 2.58 to 3.04 at 70 °C), improved mechanical elasticity (the highest at 60 °C from 48.4 to 101.1%), and reduced water vapor permeability (the highest at 70 °C from 9.00·10-10 to 6.35·10-10 g/m·s·Pa) of the analyzed films. The observations of scanning electron micrographs showed the heterogeneity of the film surface and irregular distribution of lipid droplets in the film matrix.

Antimicrobial polysaccharide hydrogels embedded with methyl-β-cyclodextrin/thyme oil inclusion complexes for exceptional mechanical performance and chilled chicken breast preservation

While hydrogels have potential for food packaging, limited research on hydrogels with excellent mechanical performance and antibacterial activity for preserving chicken breasts. Herein, we created antibacterial hydrogels by embedding methyl-β-cyclodextrin/thyme oil inclusion complexes (MCD/TO-ICs) into a polyvinyl alcohol matrix containing dendrobium polysaccharides and guar gum in varying ratios using freeze-thaw cycling method. The resulting hydrogels exhibited a more compact structure than those without MCD/TO-ICs, enhancing thermal stability and increasing glass transition temperature due to additional intermolecular interactions between polymer chains that inhibited chain movement. XRD analysis showed no significant changes in crystalline phase, enabling formation of a 3D network through abundant hydrogen bonding. Moreover, the hydrogel demonstrated exceptional durability, with a toughness of 350 ± 25 kJ/m3 and adequate tearing resistance of 340 ± 30 J/m2, capable of lifting 3 kg weight, 1200 times greater than the hydrogel itself. Additionally, the hydrogels displayed excellent antimicrobial activity and antioxidant properties. Importantly, the hydrogels effectively maintained TVB-N levels and microbial counts within acceptable ranges, preserving sensory properties and extending the shelf life of chilled chicken breasts by four days. This study highlights the potential of MCD/TO-IC-incorporated polysaccharide hydrogels as safe and effective active packaging solutions for preserving chilled chicken in food industry.

Enhancing Adhesion of Fibrin-Based Hydrogel to Polythioether Polymer Surfaces

The development of stable (bio)hybrid constructs composed of scaffolds and (bio)matrices is a major challenge in the field of tissue engineering. In the present work, the adhesion of fibrin-based hydrogels to the surface of polythioether-based polymers relevant to the 3D printing of polymer scaffolds produced by thiol-ene click chemistry was investigated. Adhesion properties were characterized by single-lap tensile shear testing. Both the sample preparation and the test method were optimized for the analysis of fibrin gel bonding to the polythioether surface. Our experimental results show that even without further modification, an adhesion between the fibrin hydrogel and polythioether is substantial, with an adhesion strength of 4.9 ± 1.0 kPa. To further improve the bonding, linear functional poly(N-vinylpyrrolidone-co-glycidyl methacrylate) (PVP-co-GMA) copolymers were used that are known for covalently binding to fibrin. The maximum adhesion strength in our study was found to be 18.4 ± 3.4 kPa. The pure PVP-co-GMA copolymers also demonstrate covalent binding to the thiol-ene-based polymers with a maximum adhesion strength of 32.2 ± 2.7 kPa. Therefore, compared to pure fibrin, the presence of copolymer coating both on the polythioether surface and in the fibrin gel led to a significant increase of the adhesion strength by a factor of 1.6.

Hybrid Materials: A Metareview

The field of hybrid materials has grown so wildly in the last 30 years that writing a comprehensive review has turned into an impossible mission. Yet, the need for a general view of the field remains, and it would be certainly useful to draw a scientific and technological map connecting the dots of the very different subfields of hybrid materials, a map which could relate the essential common characteristics of these fascinating materials while providing an overview of the very different combinations, synthetic approaches, and final applications formulated in this field, which has become a whole world. That is why we decided to write this metareview, that is, a review of reviews that could provide an eagle's eye view of a complex and varied landscape of materials which nevertheless share a common driving force: the power of hybridization.

Developing a Prolamin-Based Gel for Food Packaging: In-Vitro Assessment of Cytocompatibility

Growing environmental concerns drive efforts to reduce packaging waste by adopting biodegradable polymers, coatings, and films. However, biodegradable materials used in packaging face challenges related to barrier properties, mechanical strength, and processing compatibility. A composite gel was developed using biodegradable compounds (prolamin, d-mannose, citric acid), as a coating to increase the oxygen barrier of food packaging materials. To improve gel stability and mechanical properties, the gels were physically cross-linked with particles synthesized from tetraethyl orthosilicate and tetramethyl orthosilicate precursors. Additionally, biocompatibility assessments were performed on human keratinocytes and fibroblasts, demonstrating the safety of the gels for consumer contact. The gel properties were characterized, including molecular structure, morphology, and topography. Biocompatibility of the gels was assessed using bioluminescent ATP assay to detect cell viability, lactate dehydrogenase assay to determine cell cytotoxicity, and a leukocyte stimulation test to detect inflammatory potential. A composite gel with strong oxygen barrier properties in low-humidity environments was prepared. Increasing the silane precursor to 50 wt% during gel preparation slowed degradation in water. The addition of citric acid decreased gel solubility. However, higher precursor amounts increased surface roughness, making the gel more brittle yet mechanically resistant. The increase of precursor in the gel also increased gel viscosity. Importantly, the gels showed no cytotoxicity on human keratinocytes or fibroblasts and had no inflammatory effects on leukocytes. This composite gel holds promise for oxygen barrier food packaging and is safe for consumer contact. Further research should focus on optimizing the stability of the oxygen barrier in humid environments and investigate the potential sensitizing effects of biodegradable materials on consumers.

Eco-Design of Polymer Matrix Composite Parts: A Review

This research presents a series of analyses related to the eco-design of polymer matrix composite parts, addressing various aspects of it. The main objective was to clarify the definition of ecological design, the benefits of its implementation and its importance in all stages of obtaining a product (design, manufacturing, recycling). Global environmental issues are presented, emphasizing the importance of adopting sustainable approaches in product design and manufacturing. Special attention is paid to the analysis of waste recycling technologies for polymer matrix composite materials. The analysis carried out identifies specific ecological design principles applicable to these materials and presents recent trends in the field. Relevant case studies are highlighted, demonstrating the benefits of ecological design in order to obtain sustainable products. Additionally, the conducted research allowed for finding answers to the questions "what", "why", "when" and "how" it is necessary to apply the principles of eco-design in the case of composite materials with a polymer matrix. In general, the research promotes eco-design as an indispensable strategy for sustainable and responsible production, inspiring companies to adopt these principles for the benefit of the environment and their business performance.

Effect of the combined addition of ultrasonicated kraft lignin and montmorillonite on hydroxypropyl methylcellulose bionanocomposites

Although hydroxypropyl methylcellulose (HPMC) has been proposed as renewable substitute for traditional plastic, its barrier and active properties need to be improved. Thus, the combination of an organic residue such as kraft lignin (0-10% w/w) and a natural clay such as montmorillonite (3% w/w) by application of ultrasound can significantly improve HPMC properties. This is most likely due to the close interaction between lignin and montmorillonite, which leads to delamination of the clay and improves its dispersion within the HPMC matrix. Specifically, the addition of kraft lignin to the bionanocomposite films provided them with UV-shielding, antioxidant capacity and antibacterial activity. The incorporation of 3% montmorillonite resulted in reductions of 65.8% and 11.4% in oxygen (OP) and water vapor permeabilities (WVP), respectively. Moreover, a reduction of 43.8% in WVP was achieved when both lignin (1%) and montmorillonite (3%) were incorporated, observing a synergistic effect. Thus, the HPMC bionanocomposite with 1% lignin and 3% montmorillonite, presented good thermal stability and mechanical strength with significantly improved gas barrier permeability, as well as UV-shielding (maintaining a good transparency), antioxidant and antibacterial activities.

Plant Antimicrobials for Food Quality and Safety: Recent Views and Future Challenges

The increasing demand for natural, safe, and sustainable food preservation methods drove research towards the use of plant antimicrobials as an alternative to synthetic preservatives. This review article comprehensively discussed the potential applications of plant extracts, essential oils, and their compounds as antimicrobial agents in the food industry. The antimicrobial properties of several plant-derived substances against foodborne pathogens and spoilage microorganisms, along with their modes of action, factors affecting their efficacy, and potential negative sensory impacts, were presented. The review highlighted the synergistic or additive effects displayed by combinations of plant antimicrobials, as well as the successful integration of plant extracts with food technologies ensuring an improved hurdle effect, which can enhance food safety and shelf life. The review likewise emphasized the need for further research in fields such as mode of action, optimized formulations, sensory properties, safety assessment, regulatory aspects, eco-friendly production methods, and consumer education. By addressing these gaps, plant antimicrobials can pave the way for more effective, safe, and sustainable food preservation strategies in the future.

Cross-linked CMC/Gelatin bio-nanocomposite films with organoclay, red cabbage anthocyanins and pistacia leaves extract as active intelligent food packaging: colorimetric pH indication, antimicrobial/antioxidant properties, and shrimp spoilage tests

Multifunctional food packaging films were produced from crosslinked carboxymethyl cellulose/gelatin (CMC/Ge) bio-nanocomposites incorporated with Ge-montmorillonite (OM) nanofiller, anthocyanins (ATH) from red cabbage as colorimetric pH-indicator, and pistacia leaves extract (PE) as active agent. The influence of additives on the structural, physical, and functional properties of the films was investigated. The results showed that ATH and PE caused color alteration and reduced transparency. However, they improved the UV light barrier ability by 98 %, with less impact from OM, despite its well-dispersed state in the matrix. Increasing PE content in the bio-nanocomposite films caused an increase in compactness and surface roughness, reduction in moisture content (15.10-12.33 %), swelling index (354.55-264.58 %), surface wettability (contact angle 80.1-92.49°), water vapor permeability (7.37-5.69 × 10¹⁰ g m^-1s^-1Pa^-1), and nano-indentation mechanical parameters, without affecting the thermal stability. ATH-included films demonstrated color pH-sensitivity with improved ATH color stability through the ATH-Al³⁺ chelates formation. PE-added films exhibited effective antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, reaching 93 % of inhibition, and antimicrobial properties with biocidal effects for PE-rich film. The shrimp spoilage test showed that the T-1.5PE film offered the strongest active intelligent response. The CMC/Ge-based bio-nanocomposite films endowed with antioxidant/antimicrobial properties and colorimetric pH-sensitivity have promising potential for food packaging application.

State-of-the-Art Insights and Potential Applications of Cellulose-Based Hydrogels in Food Packaging: Advances towards Sustainable Trends

Leveraging sustainable packaging resources in the circular economy framework has gained significant attention in recent years as a means of minimizing waste and mitigating the negative environmental impact of packaging materials. In line with this progression, bio-based hydrogels are being explored for their potential application in a variety of fields including food packaging. Hydrogels are three-dimensional, hydrophilic networks composed of a variety of polymeric materials linked by chemical (covalent bonds) or physical (non-covalent interactions) cross-linking. The unique hydrophilic nature of hydrogels provides a promising solution for food packaging systems, specifically in regulating moisture levels and serving as carriers for bioactive substances, which can greatly affect the shelf life of food products. In essence, the synthesis of cellulose-based hydrogels (CBHs) from cellulose and its derivatives has resulted in hydrogels with several appealing features such as flexibility, water absorption, swelling capacity, biocompatibility, biodegradability, stimuli sensitivity, and cost-effectiveness. Therefore, this review provides an overview of the most recent trends and applications of CBHs in the food packaging sector including CBH sources, processing methods, and crosslinking methods for developing hydrogels through physical, chemical, and polymerization. Finally, the recent advancements in CBHs, which are being utilized as hydrogel films, coatings, and indicators for food packaging applications, are discussed in detail. These developments have great potential in creating sustainable packaging systems.

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

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

Approaches in Sustainable, Biobased Multilayer Packaging Solutions

The depletion of fossil resources and the growing demand for plastic waste reduction has put industries and academic researchers under pressure to develop increasingly sustainable packaging solutions that are both functional and circularly designed. In this review, we provide an overview of the fundamentals and recent advances in biobased packaging materials, including new materials and techniques for their modification as well as their end-of-life scenarios. We also discuss the composition and modification of biobased films and multilayer structures, with particular attention to readily available drop-in solutions, as well as coating techniques. Moreover, we discuss end-of-life factors, including sorting systems, detection methods, composting options, and recycling and upcycling possibilities. Finally, regulatory aspects are pointed out for each application scenario and end-of-life option. Moreover, we discuss the human factor in terms of consumer perception and acceptance of upcycling.

Adsorption of cationic surfactant as a probe of the montmorillonite surface reactivity in the alginate hydrogel composites

Adsorption of a cationic surfactant allowed to probe the surface reactivity of montmorillonite encapsulated in a composite of alginate hydrogels (A-MMT). Dodecylbenzyldimethylammonium chloride (BAC-12) was the surfactant used for these studies. BAC-12 is part of the widely used surfactant mixture known as benzalkonium chloride. XRD showed that up to three different types of basal spacing (d 001) were present within the composite indicating that as the concentration of adsorbed BAC-12 increases, populations with different adsorption conformational arrangements are present, even unexpanded clay remains. From the SEM-EDS spectra it is observed that the clay is distributed in the whole composite. In addition, the effect of the presence of cationic and anionic biocides on BAC-12 adsorption was studied. Cationic biocides such as tetradecyllbenzyldimethylammonium chlorides (BAC-14) and paraquat (PQ) show a competitive behavior for the clay adsorption sites at BAC-12 low concentration indicating an electrostatic adsorption mechanism. However, the presence of anionic contaminants such as 2,4-D and metsulfuron methyl do not affect surfactant adsorption. In all scenarios is observed an abrupt increase of BAC-12 adsorbed amount reaching values higher than the clay CEC suggesting strong tail-tail interactions. This occurs at concentrations 10 times lower than the CMC of BAC-12 promoted by clay encapsulation in the composite. In these composites the alginate does not affect the surface reactivity of the clay, but the formation of the hydrogel allows it to be easily extracted from aqueous media which makes it an interesting material with a potential use in water remediation.

Effect of Chemical Treatment of Sugar Palm Fibre on Rheological and Thermal Properties of the PLA Composites Filament for FDM 3D Printing

The thermal and rheological properties of bio-composite filament materials are crucial characteristics in the development of a bio-composite Fused Deposition Modeling (FDM) filament since the printing mechanism of FDM strongly depends on the heating and extrusion process. The effect of chemical treatment on the thermal and rheological properties was investigated to develop composite filaments for FDM using natural fibres such as sugar palm fibre (SPF). SPF underwent alkaline and silane treatment processes before being reinforced with PLA for improving adhesion and removing impurities. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetric (DSC), and Melt Flow Index (MFI) analyses were conducted to identify the differences in thermal properties. Meanwhile, a rheological test was conducted to investigate the shear stress and its viscosity. The TGA test shows that the SPF/PLA composite treated with NaOH and silane showed good thermal stability at 789.5 °C with 0.4% final residue. The DSC results indicate that the melting temperature of all samples is slightly the same at 155 °C (in the range of 1 °C), showing that the treatment does not interfere with the melting temperature of the SPF/PLA composite. Thus, the untreated SPF/PLA composite showed the highest degradation temperature, which was 383.2 °C. The SPF/PLA composite treated with NaOH and silane demonstrated the highest melt flow index of 17.6 g/min. In conclusion, these findings offer a reference point for determining the filament extrusion and printability of SPF/PLA composite filaments.

Double-Layered Films Based on Furcellaran, Chitosan, and Gelatin Hydrolysates Enriched with AgNPs in Yerba Mate Extract, Montmorillonite, and Curcumin with Rosemary Essential Oil

Double-layered active films based on furcellaran (1st layer—FUR), chitosan, and gelatin hydrolysates (2nd layer—CHIT+HGEL) were successfully prepared. Bioactive ingredients were added to the 1st film layer: AgNPs, which were synthesized in situ with yerba mate extract; montmorillonite clay (MMT); and different loads of ethanolic curcumin (CUR) extract enriched with rosemary essential oil (REO). SEM images confirmed the presence of AgNPs with a size distribution of 94.96 ± 3.33 nm throughout the films, and AFM and SEM photos indicated that the higher substance concentrations had rougher and more porous film microstructures. However, the water vapor transmission rate was reduced only at the lowest load of this ingredient. Despite the tensile strength of the films having decreased, the incorporation of the compounds showed a tendency towards reducing the modulus of elasticity, resulting in a lower stiffness of the composites. The addition of CUR and AgNPs improved the UV light barrier properties of the materials. The presented films showed quick reactions to changes in the pH value (from orange to red along with an increase in pH from 2 to 10), which indicates their potential use as indicators for monitoring the freshness of food products. Composite No. 2 showed the highest antimicrobial potential, while none of the presented films showed an antifungal effect. Finally, the antioxidant activities of the films increased dramatically at higher AgNP and CUR loads, suggesting an outstanding potential for active food packaging applications.

Marine polysaccharide laminarin embedded ZnO nanoparticles and their based chitosan capped ZnO nanocomposites: Synthesis, characterization and in vitro and in vivo toxicity assessment

In the current scenario where more and more products containing nanomaterials are on the technological or pharmaceutical market, it is crucial to have a thorough knowledge of their toxicity before proposing possible applications. A proper analysis of the toxicity of the nanoproducts should include both in vitro and in vivo biological approaches and should consider that the synthesis and purification methods of nanomaterials may affect such toxicity. In the current work, the green synthesis of laminarin embedded ZnO nanoparticles (Lm-ZnO NPs) and their based chitosan capped ZnO nanocomposites (Ch-Lm-ZnO NCmps) is described for the first time. Furthermore, the evaluation of their in vitro cytotoxicity, phytotoxicity, and in vivo (Zebrafish embryo) toxicity was described. First, the green synthesized Lm-ZnO NPs and Ch-Lm-ZnO NCmps were fully physicochemically characterized. Lm-ZnO NPs were greatly agglomerated and had a spindle morphology ranging from 100 to 350 nm, while Ch-Lm-ZnO NCmps had irregular rod shape with flake-like structure clusters randomly aggregated with diverse sizes ranging from 20 to 250 nm. The in vitro cytotoxicity assessment of the green synthesized Lm-ZnO NPs and Ch-Lm-ZnO NCmps was carried out in normal human dermal fibroblasts (HDF) cells and human colon cancer (HT-29) cells by MTT assay. Lm-ZnO NPs and Ch-Lm-ZnO NCmps (0.1-500 μg/mL), significantly inhibited the viability of both cell lines, revealing dose-dependent cytotoxicity. Besides, the Lm-ZnO NPs and Ch-Lm-ZnO NCmps significantly affected seed germination and roots and shoots length of mung (Vigna radiata). Moreover, the zebrafish embryo toxicity of Lm-ZnO NPs and Ch-Lm-ZnO NCmps among the various concentrations used (0.1-500 μg/mL) caused deformities, increased mortality and decreased the survival rate of zebrafish embryo dose-dependently.

Development of curcumin incorporated composite films based on chitin and glucan complexes extracted from Agaricus bisporus for active packaging of chicken breast meat

Composite films were prepared by combining different concentrations of curcumin with chitin and glucan complexes (CGCs) extracted from Agaricus bisporus via a solution casting method. The developed curcumin doped CGC (CGC/Cu) films were characterized in terms of surface, optical, structural, barrier, mechanical, antioxidant, and antimicrobial properties. The biodegradability of CGC/Cu films was determined in soil for 14 days. The incorporation of curcumin significantly affected the surface morphology and improved light barrier properties, radical scavenging activity, and total phenolic content of the films. The CGC/Cu films containing different concentrations of curcumin showed antibacterial activity against Escherichia coli, while antibacterial activity against Staphylococcus aureus was not observed with the developed films. Afterward, the microbial properties of the fresh chicken breast were examined during refrigerated storage for 10 days. The shelf-life of chicken samples wrapped in the developed film was extended at least 40 % compared to the control sample. In conclusion, curcumin incorporated CGC based films can serve as a promising biodegradable active packaging material to improve the shelf-life of meat products.

Intelligent labels manufactured by thermo-compression using starch and natural biohybrid based

This work aims to develop intelligent labels based on cassava starch and biohybrid pigments by thermo-compression. The biohybrid pigment (BH) was developed by the adsorption of anthocyanins (ACNs) extracted from the jambolan fruit (Syzygium cumini L.) into montmorillonite (Mt) in order to improve its stability. The effect of the addition of biohybrid on the physicochemical properties of the thermo-pressed starch labels was evaluated. ACNs from jambolan extract show a visible pH-dependent color-changing ability at pH 1 - 12, and the adsorption did not modify the color property. The intelligent labels presented a homogeneous surface, and the BH was well dispersed in the starch matrix. The presence of BH increased the solubility in the water of starch labels. Chemical structure characterization revealed that the BH interacted with starch matrices through hydrogen bonds. Furthermore, the thermal stability of starch labels increased with the presence of BH. Hence, the purple color of intelligent labels was preserved at high temperatures. Finally, labels containing BH show visible changes from purple to a blue color when exposed to ammonia vapor, which simulates the degradation of meat products. Thus, the label content jambolan pigments will be used to control meat deterioration.

Proton-Conducting Biopolymer Electrolytes Based on Carboxymethyl Cellulose Doped with Ammonium Formate

In this work, CMC-AFT biopolymer electrolytes system was developed using Carboxymethyl cellulose (CMC) doped with varied amount (10-50 wt.%) of ammonium formate (AFT) in order to study the effect of AFT on the biopolymer-salt system. The chemical structure of the biopolymer was studied using Fourier-Transform infrared (FTIR) and X-ray diffraction (XRD). The interaction between the COO^- of CMC and the weakly-bound H⁺ of NH₄⁺ AFT occurred at 1573 cm^-1 as seen in FTIR analysis and the amorphous phase was found to increase with the addition of AFT as seen from XRD pattern. Both FTIR and XRD testing indicates that the AFT had disrupted the CMC crystalline structure. The ionic conductivity of the CMC-AFT biopolymer electrolytes increases and achieved the highest value of 1.47 × 10^-4 S·cm^-1 with the addition of AFT. The impedance measurement showed that the capacitive and resistive behavior inside the biopolymer diminished when 50 wt.% of AFT was added. Dielectric analysis confirmed the increased number of charge carriers is due to the increase in AFT composition. Further dielectric analysis showed the occurrence of conductivity relaxation peak thus affirmed the charge carriers' ability to travel further to a longer distances when AFT composition increases from 10 to 50 wt.%. The dielectric properties confirmed the non-Debye behavior of the CMC-AFT biopolymer electrolytes.

Preparation and Enhanced Antimicrobial Activity of Thymol Immobilized on Different Silica Nanoparticles with Application in Apple Juice

In order to diminish the application limitations of essential oils (EOs) as natural antimicrobial components in the food industry, novel antimicrobial materials were designed and prepared by immobilization of thymol derivatives on silica particles with different morphologies (hollow mesoporous silica nanoparticles, MCM-41, amorphous silica). The structural characteristics of antimicrobial materials were estimated by FESEM, FT-IR, TGA, N2 adsorption-desorption, and small-angle XRD, and the results revealed that both mesoporous silica nanoparticles maintained the orderly structures and had good immobilization yield. Furthermore, the antibacterial performance tests showed that mesoporous silica nanoparticles greatly enhanced the antimicrobial activity of thymol against two representative foodborne bacteria (Escherichia coli and Staphylococcus aureus), and the application of the antimicrobial support was tested in apple juices inoculated with E. coli. The MBC of functionalized mesoporous silica supports was established to be below 0.1 mg/mL against E. coli and S. aureus, which is much lower than that of free thymol (0.3 mg/mL and 0.5 mg/mL against E. coli and S. aureus, respectively). In addition, at a range from 0.05 mg/mL to 0.2 mg/mL, immobilized hollow mesoporous silica nanoparticles (HMSNs) can inhibit the growth of E. coli in apple juice and maintain good sensory properties during 7 days of storage.

A green approach to develop zeolite-thymol antimicrobial composites: analytical characterization and antimicrobial activity evaluation

In this work, the development, analytical characterization and bioactivity of zeolite-thymol composites, obtained using wet, semi-dry and dry processes, were carried out in order to obtain sustainable and powerful antimicrobial additives. FT-IR, XRD, DSC, TGA, SEM and B.E.T. analyses were carried out to gain comprehensive information on the chemical-physical, thermal, and morphological features of the composites. GC-MS analyses allowed quantifying the active molecule loaded in the zeolite, released by the functionalized composites and its stability over time. Among the three procedures, the dry approach allowed to reach the highest thymol loading content and efficiency (49.8 ± 1.6% and 99.6 ± 1.2%, respectively), as well as the highest composite specific surface area value, feature which promises the best interaction between the surface of the composite and the bacterial population. Therefore, the bioactive surface of composites obtained by this solvent-free method was assayed for its antimicrobial activity against four microbial strains belonging to Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans species. The higher antimicrobial activity produced by the solvent-free composite in comparison with that of pure thymol, at the same thymol concentration, was ascribed to the large interfacial contact between the composite and the bacterial target. This feature, together with its enhanced storage stability, suggested that this composite could be employed as effective additives for the development of antimicrobial biointerfaces for food, home and personal care applications.

Supramolecular Assembly of Multifunctional Collagen Nanocomposite Film via Polyphenol-Coordinated Clay Nanoplatelets

Functional bionanocomposites have evoked immense research interests in many fields including biomedicine, food packaging, and environmental applications. Supramolecular self-assembled bionanocomposite materials fabricated by biopolymers and two-dimensional (2D) nanomaterials have particularly emerged as a compelling material due to their biodegradable nature, hierarchical structures, and designable multifunctions. However, construction of these materials with tunable properties has been still challenging. Here, we report a self-assembled, flexible, and antioxidative collagen nanocomposite film (CNF) via regulating supramolecular interactions of type I collagen and tannic acid (TA)-functionalized 2D synthetic clay nanoplatelets Laponite (LAP). Specifically, TA-coordinated LAP (LAP-TA) complexes were obtained via chelation and hydrogen bonding between TA and LAP clay nanoplatelets and further used to stabilize the triple-helical confirmation and fibrillar structure of the collagen via hydrogen bonding and electrostatic interactions, forming a hierarchical microstructure. The obtained transparent CNF not only exhibited the reinforced thermal stability, enzymatic resistance, tensile strength, and hydrophobicity but also good water vapor permeability and antioxidation. For example, the tensile strength was improved by over 2000%, and the antioxidant property was improved by 71%. Together with the simple fabrication process, we envision that the resulting CNF provides greater opportunities for versatile bionanocomposites design and fabrication serving as a promising candidate for emerging applications, especially food packaging and smart wearable devices.

Composite Films of Nanofibrillated Cellulose with Sepiolite: Effect of Preparation Strategy

Cellulose nanofibrils (CNFs) are nanomaterials with promising properties to be used in food packaging and printed electronics, thus being logical substitutes to petroleum-based polymers, specifically plastics. CNFs can be combined with other materials, such as clay minerals, to form composites, which are environmentally friendly materials, with acceptable costs and without compromising the final properties of the composite material. To produce composite films, two strategies can be used: solvent casting and filtration followed by hot pressing. The first approach is the simplest way to produce films, but the obtained films may present some limitations. In the present work, CNFs produced using enzymatic or TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) oxidation pretreatments, followed by high-pressure homogenization, or only by mechanical treatment (homogenization), were used to produce films by both the available procedures. The films obtained by filtration + hot pressing presented higher tensile strength and Young’s modulus compared with those obtained by solvent casting. In general, a decrease in the values of these mechanical properties of the films and a decrease in elongation at break, with the addition of sepiolite, were also observed. However, for the TEMPO CNF-based films, an improvement in tensile strength could be observed for 10% of the sepiolite content. Furthermore, the time necessary to produce films was largely reduced by employing the filtration procedure. Finally, the water vapour barrier properties of the films obtained by filtration are comparable to the literature values of net CNF films. Thus, this technique demonstrates to be the most suitable to produce CNF-based composite films in a fast way and with improved mechanical properties and suitable gas barrier properties.

Tailoring Poly(lactic acid) (PLA) Properties: Effect of the Impact Modifiers EE-g-GMA and POE-g-GMA

Poly(ethylene-octene) grafted with glycidyl methacrylate (POE-g-GMA) and ethylene elastomeric grafted with glycidyl methacrylate (EE-g-GMA) were used as impact modifiers, aiming for tailoring poly(lactic acid) (PLA) properties. POE-g-GMA and EE-g-GMA was used in a proportion of 5; 7.5 and 10%, considering a good balance of properties for PLA. The PLA/POE-g-GMA and PLA/EE-g-GMA blends were processed in a twin-screw extruder and injection molded. The FTIR spectra indicated interactions between the PLA and the modifiers. The 10% addition of EE-g-GMA and POE-g-GMA promoted significant increases in impact strength, with gains of 108% and 140%, respectively. These acted as heterogeneous nucleating agents in the PLA matrix, generating a higher crystallinity degree for the blends. This impacted to keep the thermal deflection temperature (HDT) and Shore D hardness at the same level as PLA. By thermogravimetry (TG), the blends showed increased thermal stability, suggesting a stabilizing effect of the modifiers POE-g-GMA and EE-g-GMA on the PLA matrix. Scanning electron microscopy (SEM) showed dispersed POE-g-GMA and EE-g-GMA particles, as well as the presence of ligand reinforcing the systems interaction. The PLA properties can be tailored and improved by adding small concentrations of POE-g-GMA and EE-g-GMA. In light of this, new environmentally friendly and semi-biodegradable materials can be manufactured for application in the packaging industry.

Polysaccharide-Based Active Coatings Incorporated with Bioactive Compounds for Reducing Postharvest Losses of Fresh Fruits

This review reports recently published research related to the application of polysaccharide-based biodegradable and edible coatings (BECs) fortified with bioactive compounds obtained from plant essential oils (EOs) and phenolic compounds of plant extracts. Combinations of polysaccharides such as starches, pectin, alginate, cellulose derivatives, and chitosan with active compounds obtained from clove, lemon, cinnamon, lavender, oregano, and peppermint have been documented as potential candidates for biologically active coating materials for retardation of quality changes in fresh fruits. Additionally, polysaccharide-based active coatings supplemented with plant extracts such as cashew leaves, pomegranate peel, red roselle, apple fiber, and green tea extracts rich in phenolic compounds and their derivatives have been reported to be excellent substituents to replace chemically formulated wax coatings. Moreover, EOs and plant polyphenolics including alcohols, aldehydes, ketones phenols, organic acids, terpenes, and esters contain hydroxyl functional groups that contribute bioactivity to BECs against oxidation and reduction of microbial load in fresh fruits. Therefore, BECs enriched with active compounds from EOs and plant extracts minimize physiological and microbial deterioration by reducing moisture loss, softening of flesh, ripening, and decay caused by pathogenic bacterial strains, mold, or yeast rots, respectively. As a result, shelf life of fresh fruits can be extended by employing active polysaccharide coatings supplemented with EOs and plant extracts prior to postharvest storage.

Study of Thermal, Mechanical and Barrier Properties of Biodegradable PLA/PBAT Films with Highly Oriented MMT

In order to improve the properties of biodegradable polylactide (PLA), mixtures with polybutylene adipate-co-terephthalate (PBAT) were prepared. PLA is a bio-based and renewable biodegradable material, made from starch. PBAT is a biodegradable polyester for compostable film. In order to improve the composite properties, two types of additives were implemented via melt mixing, a chain extender (CE) and montmorillonite (MMT). CE was used as an interfacial modifier to enhance the adhesion between components. Montmorillonite is a widely studied clay added to polymer nanocomposites. Due to the lamellar structure, it improves the barrier properties of materials. PLA/PBAT films were oriented in the extrusion process and the amounts of filler introduced into the PLA/PBAT nanocomposites were 1.0, 3.0, and 5.0%. The improvement in the PLA barrier properties by the addition of PBAT and 5% of MMT was confirmed as the oxygen permeability decreased almost by a factor of 3. The addition of the biodegradable polymer, chain extender, montmorillonite, and the implemented orientation process resulted in a decrease in composite viscosity and an increase in the PLA crystallinity percentage (up to 25%), and the wettability tests confirmed the synergic behavior of the selected polymer blend.

Rosmarinic Acid and Ulvan from Terrestrial and Marine Sources in Anti-Microbial Bionanosystems and Biomaterials

In order to increase their sustainability, antimicrobial renewable molecules are fundamental additions to consumer goods. Rosmarinic acid is extracted from several terrestrial plants and represents an effective anti-microbial agent. Ulvan, extracted from algae, is an anti-microbial polysaccharide. The present review is dedicated to discussing the sources and the extraction methodologies for obtaining rosmarinic acid and ulvan. Moreover, the preparation of bioanosystems, integrating the two molecules with organic or inorganic substrates, are reviewed as methodologies to increase their effectiveness and stability. Finally, the possibility of preparing functional biomaterials and anti-microbial final products is discussed, considering scientific literature. The performed analysis indicated that the production of both molecules is not yet performed with mature industrial technologies. Nevertheless, both molecules could potentially be used in the packaging, biomedical, pharmaceutical, cosmetic, sanitary and personal care sectors, despite some research being required for developing functional materials with specific properties to pave the way for many more applications.

Preparation of pectin/agar-based functional films integrated with zinc sulfide nano petals for active packaging applications

Here we report on the robust synthesis of zinc sulfide nanoparticles (ZnSNP) using a simple one-pot reaction. The prepared ZnSNP was characterized and confirmed to be a petal-shaped nanoparticle. The ZnSNP was added to fabricate the pectin/agar-based functional composite film. The integration of ZnSNP has greatly improved the physical properties of the film, such as mechanical and UV protection properties, without significantly changing the transparency of the film. The addition of the nanofillers did not affect the film's hydrophobicity, water vapor barrier, and thermal properties. Moreover, the composite film showed intense antibacterial activity against foodborne pathogenic bacteria, E. coli and L. monocytogenes. The functional bio-nanocomposite films based on pectin/agar have high potential in active packaging applications.

Cellulose Nanofibers from Olive Tree Pruning as Food Packaging Additive of a Biodegradable Film

A biodegradable packaging film containing cellulose nanofibers from olive tree pruning, a by-product of olives production, was obtained using a solvent casting method. Nanocellulose was added to polyvinyl alcohol (PVA) to enhance the technological properties of the composite film as food packaging material. Nanocellulose was obtained from unbleached and bleached pulp through a mechanical and TEMPO pretreatment. Crystalline and chemical structure, surface microstructure, UV and gas barrier, optical, mechanical and antioxidant properties, as well as thermal stability were evaluated. Regarding optical properties, the UV barrier was increased from 6% for the pure PVA film to 50% and 24% for unbleached and bleached nanocellulose, respectively. The antioxidant capacity increased significantly in unbleached mechanical nanocellulose-films (5.3%) compared to pure PVA film (1.7%). In terms of mechanical properties, the tensile strength of the 5% unbleached mechanical nanocellulose films was significantly improved compared to the pure PVA film. Similarly, the 5% nanocellulose films had increased the thermal stability and improved barrier properties, reducing water vapor permeability by 38–59% and presenting an oxygen barrier comparable to aluminum layer and plastic films. Our results support the use of the developed films as a green alternative material for food packaging.