Ethyl vanillin incorporated chitosan/poly(vinyl alcohol) active films for food packaging applications

Liposome/chitosan coating film bioplastic packaging for Litchi fruit preservation

Chitosan is an ideal coating film for food preservation, but the performance of a single chitosan coating film is not good. Herein, the liposome was prepared by embedding copper nanoparticles (CuNPs) and thyme essential oil (TEO) in the hydrophilic and hydrophobic double-domain structure formed by phospholipids, and combining with chitosan to obtain a chitosan-based coating film for litchi preservation. The liposome was well-dispersed and stable with an average particle size of about 190 nm. The liposome showed excellent controllable release properties, and the cumulative release rate of TEO was 65.17 % and that of CuNPs was 15.17 % after 7 days. Furthermore, the oxygen and water vapor barrier properties of the coating film were greatly improved. Importantly, the film possessed effective antioxidant, antibacterial activity and excellent safety, which presents a better fresh-keeping effect on litchi. This study provides insights into the design and manufacture of food packaging for controllable and long-lasting preservation.

Fabrication and characterization of electrospun core-shell nanofibers of bilayer zein/pullulan emulsions crosslinked by genipin

In this study, the electrospun core-shell nanofibers of zein/pullulan stabilized bilayer emulsions before and after genipin crosslinking were fabricated. The experimental results indicated that the addition of pullulan increased the apparent viscosity and elastic modulus of the bilayer emulsions, which was further increased after the chemical crosslinking of genipin. The nanofiber diameter increased from 102.9 nm to 169.9 nm with the increasing ratio of pullulan, but increased significantly to a range of 405.6-708.0 nm after genipin crosslinking. The electrospun nanofiber films of crosslinked emulsions had higher thermal stability and stronger water stability. The FTIR result proved the existence of hydrogen bond interaction between the zein, pullulan, and genipin molecules. In addition, before and after crosslinking, the encapsulation efficiency of electrospun fiber films for camellia oil was >77.68 %, and the maximum encapsulation efficiency could reach 87.94 %, and there was no significant change during the 7-day storage period, showing good stability. These research results can provide a theoretical basis for the encapsulation of hydrophobic active substances in zein-based emulsion electrospun core-shell nanofibers.

Water-resistant and barrier properties of poly(vinyl alcohol)/nanocellulose films enhanced by metal ion crosslinking

Polyvinyl alcohol (PVA) is a promising alternative to non-biodegradable flexible packaging materials, and nanocellulose is often used to enhance the properties of PVA films, but the composite films still have poor water resistance and barrier properties. To address this issue, iron ions (Fe3+) were introduced into PVA/cellulose nanofibrils (CNF) films, and Fe3+ formed coordination bonds with carboxyl and hydroxyl groups on the surface of CNF and PVA chains. Therefore, constructing a strong coordination crosslinking network within the film and improving the interfacial interaction between PVA and CNF. The water resistance, mechanical and barrier properties of the crosslinked films were significantly improved. Compared with the un-crosslinked film, the oxygen transmission rate (OTR) was decreased by up to 67 %, and the water swelling ratio was significantly reduced from 1085 % to 352 %. The tensile strength of the film with 1.5 wt% Fe3+ reached 41.93 MPa, which was 62 % higher than that of the un-crosslinked film. Furthermore, the composite film demonstrated good recyclability, almost recovering its original mechanical properties in two recycling tests. This simple and effective method for preparing water resistance and barrier films shows potential applications in flexible packaging areas.

A synergistic influence of gallic acid/ZnO NPs to strengthen the multifunctional properties of methylcellulose: A conservative approach for tomato preservation

Biodegradable and sustainable food preservation materials have gained immense global importance to mitigate plastic pollution and environmental impact. Biopolymers like cellulose offer significant advantages for food preservation, including biodegradability and the ability to extend shelf life. Therefore, the present study aims to prepare gallic acid (GA) and zinc oxide nanoparticles (ZnO NPs) incorporated methylcellulose (MC) composite films by employing a solvent casting technique. The homogeneous SEM micrographs and FTIR spectra evidenced high compatibility among MC and GA/ZnO NPs. The UV barrier capacity, mechanical properties and surface hydrophobicity are remarkably enhanced by GA/ZnO NPs. However, the water vapour permeability and oxygen permeability of MGZ films were reduced by 49.19 % and 57.75 % respectively. Moreover, the MGZ films demonstrated exceptional antioxidant efficacy (∼94.48 %) and inhibition against food-borne pathogens such as B. subtilis, S. aureus (Gram-positive), E. coli, P. aeruginosa (Gram-negative), and C. albicans fungi. Furthermore, the GA/ZnO NPs extended the shelf life of MGZ coated tomato samples up to 27 days and exhibited controlled microbial growth after the preservation study. These results support the application of MGZ films as suitable and effective coating materials for food packaging applications.

Vanillin-based flame retardant enables polylactic acid high-efficiency fireproof, anti-UV and oxygen barrier for food packaging

Polylactic acid (PLA) is widely known for its biocompatibility, biodegradability, and high transparency. However, it still has varied limitations such as flammability, UV sensitivity, and poor oxygen barrier properties. To address these issues, a bio-based compound, hexasubstituted cyclotriphosphazene (HVP), was synthesized by using vanillin and hexachlorocyclotriphosphazene to enhance the overall performance of PLA. The resulting PLA/HVP composites demonstrated improved mechanical strength and UV resistance. Specifically, PLA/3HVP, with a 3 wt% HVP loading, achieved a UL-94 V-0 rating and a high limiting oxygen index of 26.5 %. Cone calorimeter tests revealed that PLA/3HVP possessed a significantly longer ignition time and a lower peak heat release rate compared to pure PLA. These burning testing results indicated the enhanced fire resistance. Additionally, the oxygen transmission rate of PLA/3HVP was reduced by 81.1 % compared to pure PLA. When used as food packaging, the weight loss of mangoes covered with PLA/3HVP film was 2.2 % after 7 days, compared to 2.5 % with pure PLA film, highlighting its potential for food preservation applications.

Development of Edible Coatings Based on Pineapple Peel (Ananas Comosus L.) and Yam Starch (Dioscorea alata) for Application in Acerola (Malpighia emarginata DC)

Acerola fruit has great nutritional and economic relevance; however, its rapid degradation hinders commercialization. The use of coatings reduces post-harvest biochemical modifications and provides physical and biological protection for vegetables such as acerola. This study developed and characterized an edible coating made from pearl pineapple peel flour (PPPF) and yam starch (YS) to preserve the quality standards of acerola fruits during storage at room temperature and under refrigeration. The edible coating, composed of 4 g of PPPF, 3 g of starch, and 10% glycerol, presented excellent moisture content (11%), light tone (L* 83.68), and opacity (45%), resistance to traction of 27.77 Mpa, elastic modulus of 1.38 Mpa, and elongation percentage of 20%. The total phenolic content of the coating was 278.68 ± 0.45 mg GAE/g and the antioxidant activity by DPPH was 28.85 ± 0.27%. The quality parameters of acerolas were evaluated with three treatments: T1-uncoated fruits; T2-fruits coated with 1% glycerol; and T3-fruits coated with PPPF-YS. The T3 treatment reduced the weight loss of stored acerolas, maintaining the light and bright color of the fruits, and delayed the decrease in soluble solids, especially in refrigerated fruits. Therefore, edible coatings based on pineapple flour and yam starch are effective technologies for controlling the physical and physicochemical parameters of acerolas during storage, benefiting the post-harvest quality of this fruit.

A chitosan-based hydrogel loaded with fenofibrate for diabetic wound healing

Diabetic wounds represent a common chronic condition, posing significant challenges in the treatment process due to bacterial infections, increased generation of reactive oxygen species (ROS) and exacerbated inflammation. Fenofibrate (FEN) is a clinical medication used for lipid regulation. In this study, it was utilized for the first time as an effective component of wound dressings for treating diabetic ulcers, exploring its novel applications further. Therefore, we prepared a polyvinyl alcohol/chitosan/FEN (PCF) hydrogel using a freeze-thaw method and conducted physicochemical characterization of the PCF hydrogel to further elucidate its biological functions. In vitro studies demonstrated that the PCF hydrogel exhibits excellent biocompatibility along with significant antimicrobial, pro-angiogenic, ROS-scavenging, and anti-inflammatory properties. Subsequent animal experiments indicated that the PCF hydrogel has the ability to promote blood vessel formation and collagen deposition. Additionally, the PCF hydrogel showed a significant inhibitory effect on the inflammatory response, as evidenced by the reductions in the levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). These compelling findings accentuate the promising application of the PCF hydrogel in the treatment of diabetic wounds.

Preparation and Keep-Refreshing Effect of Chitosan/Sea Buckthorn Polysaccharide Composite Film on the Preservation of Yellow Cherry Tomatoes

In this study, sea buckthorn polysaccharides (SBP) were added as functional substances to chitosan (CS), and chitosan/sea buckthorn polysaccharide (SCS) composite films were prepared using the casting method. The effects of SBP addition on the optical properties, physical properties, mechanical properties, structure, antioxidant activity, and antibacterial activity of the SCS composite films were studied, and the prepared SCS composite films were used to preserve yellow cherry tomatoes. The results showed that SCS composite films exhibited good UV resistance, water solubility, and antioxidant activity, but its apparent structure, hydrophobicity, and mechanical properties needed further improvement. Meanwhile, SBP has inhibitory effects on all 8 experimental strains. In addition, the SCS composite film with the addition of 200 mg/L SBP could reduce the weight loss rate of yellow cherry tomatoes, maintain hardness, delay the decrease of total soluble solids, titratable acid, and Vitamin C content, and inhibit the accumulation of malondialdehyde. SCS composite films are beneficial for enhancing the quality of yellow cherry tomatoes during storage, and their application in fruit and vegetable preservation has development prospects.

Preparation of chitosan photodynamic antibacterial film loaded with VK3 complex in the preservation of chilled mutton

To effectively utilize the photodynamic antibacterial ability of vitamin K3 (VK3), by solving the photothermal instability of VK3, it was combined with natural polymers to apply the preservation of chilled mutton. We encapsulated VK3 in the (2-Hydroxypropyl)-β-cyclodextrin (HP-β-CD) to construct VK3-HP-β-CD complex and then introduced the complex to chitosan (CS) and polyvinyl alcohol (PVA) to fabricate an antibacterial film (CS/PVA-VK3-HP-β-CD film). Through the packaging performance test of the film, the content of VK3-HP-β-CD was an important factor determining the properties of film including tensile strength, elongation at break, water vapor permeability, water content and water contact angle. Meanwhile, CS/PVA-VK3-HP-β-CD films could continuously release ROS under light and suspended in dark, thus realizing >99 % antibacterial rate for Escherichia coli and Staphylococcus aureus. In the application experiment of chilled mutton, CS/PVA-VK3-1-HP-β-CD film could significantly inhibit the increase of total viable count (TVC), pH value (pH) and total volatile base nitrogen (TVB-N) of chilled mutton, and extended its shelf life for at least 12 days. These results indicated that the CS/PVA film with the VK3-HP-β-CD complex might have promising potential as an antibacterial material for packaging and preserving food.

Heat-sealable, transparent, and degradable arabinogalactan/polyvinyl alcohol films with UV-shielding, antibacterial, and antioxidant properties

Petroleum-based packaging materials are nondegradable and unsustainable and thus are harmful to the environment. Renewable packaging films prepared from bio-based raw materials are promising alternatives to petroleum-based packaging materials. In this study, colorless and transparent bio-based films were successfully cast using a solution containing a mixture of arabinogalactan (AG) and poly (vinyl alcohol) (PVA). Vanillin was incorporated into the mixture to endow the films with UV-shielding, antioxidant, and antibacterial properties. The morphological, physical, antioxidant, and antibacterial properties of the blend films were then characterized. At an AG:PVA weight ratio of 1:3, and the vanillin content was 0.15 %, the tensile strength of the AG/PVA/Vanillin (APV) films reached ~28 MPa, while their elongation at break reached ~475 %. The addition of vanillin significantly affected the antioxidant and antibacterial properties of the blend films, which exhibited superb UV barrier capacity. The APV films exhibited extremely low oxygen transmittance, delaying the onset of mold/rot in strawberries and reducing their weight loss. Because of the heat sealability of the blend films, they can be used for encapsulating various substances, such as concentrated laundry liquid. Moreover, the blend films were recyclable and biodegradable. Thus, these films have great potential for applications that require sustainable packaging.

Recent advancements in chitosan-based intelligent food freshness indicators: Categorization, advantages, and applications

With an increasing emphasis on food safety and public health, there is an ongoing effort to develop reliable, non-invasive methods to assess the freshness of diverse food products. Chitosan-based food freshness indicators, leveraging properties such as biocompatibility, biodegradability, non-toxicity, and high stability, offer an innovative approach for real-time monitoring of food quality during storage and transportation. This review introduces intelligent food freshness indicators, specifically those utilizing pH-sensitive dyes like anthocyanins, curcumin, alizarin, shikonin, and betacyanin. It highlights the benefits of chitosan-based intelligent food freshness indicators, emphasizing improvements in barrier and mechanical properties, antibacterial activity, and composite film solubility. The application of these indicators in the food industry is then explored, alongside a concise overview of chitosan's limitations. The paper concludes by discussing the challenges and potential areas for future research in the development of intelligent food freshness indicators using chitosan. Thus, chitosan-based smart food preservation indicators represent an innovative approach to providing real-time data for monitoring food quality, offering valuable insights to both customers and retailers, and playing a pivotal role in advancing the food industry.

Noni (Morinda citrifolia) leaf extract incorporated methylcellulose active films: A sustainable strategy for browning inhibition in apple slice packaging

Methylcellulose, a prominent polysaccharide prevalent in the food sector, was considered to fabricate the active films with glutaraldehyde as a crosslinker and Noni (Morinda citrifolia) Leaf Extract (NLE) as an active agent. FTIR analysis confirms the intermolecular -OH bonding, and SEM micrograms demonstrate methylcellulose active films' homogeneous, dense morphologic appearance. Due to the crosslinking effect of glutaraldehyde and noni leaf extract, tensile strength (41.83 ± 0.134 MPa) and crystallinity (62.91 %) of methylcellulose films were improved. Methylcellulose active films suppress water and moisture uptake at various relative humidities. The inhibition capability against foodborne pathogens and the excellent antioxidant activity [DPPH (93.191 ± 1.384 %) and ABTS (90.523 ± 1.412 %)] of NLE incorporation suggested that food packed in methylcellulose active films were effective against pathogenic and oxidative attacks. During preservation, to ensure the apple slices' nutritional values, they are covered with physiochemically enhanced methylcellulose active films for up to 120 h. The minimum reduction in vitamin C, reducing sugar content, percentage weight loss, pH, and total phenolic content of apple slices preserved in MGN active films at room temperature suggests it is an affordable and efficient replacement to traditional single-use plastic packaging in the cut fruit industry.

Vanillin/fungal-derived carboxy methyl chitosan/polyvinyl alcohol hydrogels prepared by freeze-thawing for wound dressing applications

In this study, we developed hydrogels using polyvinyl alcohol (PVA), vanillin (V), and a fungus-derived carboxymethyl chitosan (FC) using a freeze-thaw-based method. These hydrogels were strengthened by bonding, including Schiff's base bonding between V and FC and hydrogen bonding between PVA, FC, and V. The physiological properties of these PFCV hydrogels were characterized by FTIR, TGA, compressive mechanical testing, and rheology and water contact angle measurements. FTIR spectra confirmed the effective integration of FC and V into the PVA network. TGA results showed that FC and V enhanced the thermal stability of PFCV hydrogels. Mechanical tests showed increasing the amount of V reduced mechanical properties but did not alter the elastic character of hydrogels. SEM images displayed a well-interconnected porous structure with excellent swelling capacity. In addition, we examined biological properties using cell-based in vitro studies and performed antibacterial assessments to assess suitability for potential wound dressing applications. Prestoblue™ and live/dead cell analysis strongly supported skin fibroblast attachment and viability, DPPH assays indicated substantial antioxidant activity, and PFCV hydrogels showed enhanced antibacterial effects against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). In summary, incorporating V and FC into PVA hydrogels appears to be attractive for wound dressing applications.

A comprehensive review of eclectic approaches to the biological synthesis of vanillin and their application towards the food sector

Vanillin, a highly regarded flavor compound, has earned widespread recognition for its natural and aromatic qualities, piquing substantial interest in the scientific community. This comprehensive review delves deeply into the intricate world of vanillin synthesis, encompassing a wide spectrum of methodologies, including enzymatic, microbial, and immobilized systems. This investigation provides a thorough analysis of the precursors of vanillin and also offers a comprehensive overview of its transformation through these diverse processes, making it an invaluable resource for researchers and enthusiasts alike. The elucidation of different substrates such as ferulic acid, eugenol, veratraldehyde, vanillic acid, glucovanillin, and C6-C3 phenylpropanoids adds a layer of depth and insight to the understanding of vanillin synthesis. Moreover, this comprehensive review explores the multifaceted applications of vanillin within the food industry. While commonly known as a flavoring agent, vanillin transcends this role by finding extensive use in food preservation and food packaging. The review meticulously examines the remarkable preservative properties of vanillin, providing a profound understanding of its crucial role in the culinary and food science sectors, thus making it an indispensable reference for professionals and researchers in these domains.

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Design and fabrication of polysaccharide based excellent chemical resistant and UV barrier ternary blend films for green packaging applications

The development of green materials for active packaging applications is a research hotspot due to setbacks of petrochemical derived plastics. Thus, the present study aims to develop ternary blend films by doping different wt% of Tragacanth gum (TG) to Poly(vinyl alcohol)/Chitosan (PC) blend using solvent evaporation technique. Further, their various physicochemical properties were evaluated systematically. Differential scanning calorimetry studies revealed excellent compatibility and thermal stability of PC blend was significantly reinforced with 15 wt% of TG. UV-visible spectroscopy study demonstrated the excellent shielding efficacy of UV radiation by ternary blend films. Moreover, overall migration results confirmed the limited release of film constituents into food simulants and swelling ratio analysis indicated the good swelling resistance at higher wt% of TG. The ternary films exhibited tremendous chemical resistance against extreme acidic and basic environments and these green biofilms could be considered for active packaging applications.

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Progress on green crosslinking of polysaccharide hydrogels for drug delivery and tissue engineering applications

Natural polysaccharides are being studied for their biocompatibility, biodegradability, low toxicity, and low cost in the fabrication of various hydrogel devices. However, due to their insufficient physicochemical and mechanical qualities, polysaccharide hydrogels alone are not acceptable for biological applications. Various synthetic crosslinkers have been tested to overcome the drawbacks of standalone polysaccharide hydrogels; however, the presence of toxic residual crosslinkers, the generation of toxic by-products following biodegradation, and the requirement of toxic organic solvents for processing pose challenges in achieving the desired non-toxic biomaterials. Natural crosslinkers such as citric acid, tannic acid, vanillin, gallic acid, ferulic acid, proanthocyanidins, phytic acid, squaric acid, and epigallocatechin have been used to generate polysaccharide-based hydrogels in recent years. Various polysaccharides, including cellulose, alginate, pectin, hyaluronic acid, and chitosan, have been hydrogelized and investigated for their potential in drug delivery and tissue engineering applications using natural crosslinkers. We attempted to provide an overview of the synthesis of polysaccharide-based hydrogel systems (films, complex nanoparticles, microspheres, and porous scaffolds) based on green crosslinkers, as well as a description of the mechanism of crosslinking and properties with a special emphasis on drug delivery, and tissue engineering applications.

Preparation and characterization of gelatin/chitosan nanocomposite reinforced by NiO nanoparticles as an active food packaging

Food packaging with antibacterial properties has attracted much attention recently. In this study, nickel oxide nanoparticles (NiONPs) were synthesized by co-precipitation and then gelatin/chitosan polymer films (GEL/CS) with different percentages of NiONPs, bio-nanocomposites, were prepared by casting. Morphology, crystal microstructure, molecular interactions and thermal stabilities of the NPs and the composite films were characterized by FESEM, XRD, FTIR and TGA, respectively. The bio-nanocomposite films exhibited excellent barrier, thermal and mechanical properties by addition of an optimized content of NPs. For example, the tensile strength (TS) of the GEL/CS film without NPs was 23.83 MPa and increased to 30.13 MPa by incorporation of 1% NPs. The antibacterial properties and toxicity of the films were investigated. These films show good antibacterial behavior against Gram-positive (Staphylococcus aureus) bacteria compared to Gram-negative (Escherichia coli) bacteria. Furthermore, the films were found to be non-toxic to fibroblast cells that came into contact with the films, with a survival rate of more than 88%. Therefore, these films can be applied for food packaging due to their excellent mechanical, barrier, and antibacterial properties.

Vanillin loaded-physically crosslinked PVA/chitosan/itaconic membranes for topical wound healing applications

Vanillin loaded-physically crosslinked hydrogel membranes made of PVA/chitosan/itaconic acid (PVA-CS-IA) were prepared using freezing-thawing (F-T) cycle method. To ensure the entanglement of PVA-CS-IA chains, three F-T cycles were repeated. The polymeric chains entanglements were confirmed and characterized by different instrumental characterizations. Physicochemical properties for example, swelling ratio, mechanical characteristics, gel fraction percentage (GF%), hydrolytic degradation, and thermal stability of PVA-CS-IA membrane were discussed in detail. The findings showed that the swelling ratio, mechanical characteristics, and hydrolytic degradation of the crosslinked membranes enhanced with increasing CS-IA contents in membranes composition; however, GF% gradually declined with CS-IA content. Additionally, cell viability test using HFB-4 cell line and antimicrobial activity against Staphylococcus aureus and Escherichia coli were evaluated using MTT assay and the bacterium growth inhibition percentage method; respectively. Notably, with varying incubation durations and membrane concentrations, all examined constructed hydrogels showed significant cell survival percentages. The findings supported the notion that produced hydrogel membranes might be used in a professional setting as antibacterial dressings or biomaterials for quick wound healing rate.

Preparation, physicochemical and biological evaluation of chitosan Pleurotus ostreatus polysaccharides active films for food packaging

The aim of this study was to create CS-POP composite films by blending Pleurotus ostreatus stalk polysaccharides (POP) and chitosan (CS). The effects of adding different concentrations (0 %, 0.25 %, 0.5 %, 0.75 %, and 1 %) of POP on the mechanical, barrier, and optical properties of the CS films were investigated. When the POP content is at 0.5 %, the tensile strength of the composite film reaches its maximum value at 13.691 MPa, showing a significant improvement compared to the tensile strength of the pure CS film. The structure of the CS and CS-POP composite films was characterized by FT-IR spectroscopy, XRD, TGA and SEM. The results indicate that due to the interaction between the two types of CS and POP, the formation of Schiff base, and the intermolecular hydrogen bonds between CS and POP, the addition of POP to CS films can result in a smoother and more stable crystalline structure in the composite film. The CS-POP composite films exhibited enhanced antioxidant and antibacterial activity compared to the CS films alone, with the highest DPPH scavenging activity of 72.43 %. The composite films also showed significant inhibitory effects on the growth of E. coli.

Multifunctional composite films based on polyvinyl alcohol, quaternary ammonium salt modified cellulose nanofibers and tannic acid-iron ion coordination complexes for food packaging

The development of sustainable and well-performing food packaging materials takes on critical significance, whereas it is still challenging. To overcome the shortcomings of polyvinyl alcohol (PVA) as a degradable packaging material, in this work, hydrophobic quaternary ammonium salt (QAS) modified cellulose nanofibers (CNF) and tannic acid‑iron ion coordination complexes (TA-Fe) were adopted for the preparation of functional PVA films. The modified CNF (CNF-QAS) not only improved the mechanical properties and water resistance of PVA, but also endowed it with antibacterial ability. In addition, the synergistic antibacterial capability with CNF-QAS was achieved using TA-Fe with photothermal therapy. As a result, the modulus, elongation at break, tensile strength, and water contact angle of the prepared PVA films were examined as 88 MPa, 200 %, 11.7 MPa, and 94.8°, respectively. Furthermore, with the assistance of CNF-QAS and TA-Fe, the films inhibited the growth of E. coli and S. aureus by 99.8 % and 99.7 %, respectively, and they exhibited high cell viability of 90.5 % for L929 fibroblasts. Based on the above encouraging properties, the functional PVA films could significantly extend the shelf life of oranges for over two weeks, proving the excellent application prospects in the food packaging field.

Physicochemical and antioxidant properties of tannic acid crosslinked cationic starch/chitosan based active films for ladyfinger packaging application

In the present study, cationic starch (CS)/chitosan (CH) incorporated with tannic acid (TA)(CSCT) eco-friendly films were prepared by employing an inexpensive solvent casting technique. Influence of TA on the physicochemical and antimicrobial properties of CS/CH polymer matrix were studied. The FTIR findings and homogeneous, dense SEM micrographs confirms the effective interaction of TA with CS/CH polymer matrix. CSCT-3 active film displayed tensile strength of 26.99±1.91 MPa, which is more substantial than commercially available polyethylene (PE) (12-16 MPa) films. The active films exhibited excellent barrier properties against moisture and water, supported by increased water contact angle values (86.97±0.29°). Overall migration rate of active films was found to be below the permitted limit of 10mg/dm2. The active films showed around 56% of degradation in soil within 15 days. Besides, the active films showed concurring impact against food borne pathogens like E. coli, S. aureus and C. albicans. The CSCT-3 active film presented 90.83% of antioxidant capacity, demonstrating the effective prevention of food oxidation related deterioration. Ladyfinger packaging was inspected to examine the ability of active films as packaging material resulted in effectively resisting deterioration and extending shelf life in comparison with traditional PE packaging.

Development of curcumin-containing polyvinyl alcohol/chitosan active/intelligent films for preservation and monitoring of Schizothorax prenanti fillets freshness

Active/intelligent films for the preservation and monitoring of Schizothorax prenanti fillets freshness were prepared by combining curcumin (CUR) with polyvinyl alcohol/chitosan (PVA/CS) matrix. SEM images showed that the CUR with a maximum content of 1.5 % (w/w) was evenly distributed in the composite matrix. The addition of CUR did not affect the chemical structure of PVA/CS matrix, as confirmed by FTIR investigation. When 1.5 % (w/w) CUR was added, the water vapor barrier property, tensile strength and antioxidant activity of the composite film were the best, which were 5.38 ± 0.25 × 10-11 g/m·s·Pa, 62.05 ± 1.68 MPa and 85.50 ± 3.63 %, respectively. Water solubility of PVA/CS/CUR-1.5 % film was reduced by approximately 27 % compared to PVA/CS film. After adding CUR, the antibacterial properties of the composite film increased significantly. Although the addition of CUR reduced the biodegradability of PVA/CS film, the PVA/CS/CUR-1.5 % film degraded >60 % within 5 weeks. By measuring pH, weight loss, total volatile base‑nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and total viable counts (TVC), the preservation effect of the composite films on the fish freshness was evaluated. The fish shelf life treated by PVA/CS/CUR-1.5 % film expanded from 3-6 days to 12-15 days at 4 °C. In addition, when PVA/CS/CUR-1.5 % film was used to monitor the fish freshness, it exhibited clear color fluctuations, from yellow to orange and to red, corresponding to first-grade freshness, second-grade freshness, and rottenness of the fish, respectively. As a result, the films can be successfully used for Schizothorax prenanti fillets preservation and deterioration monitoring.

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

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

Innovations in Food Packaging for a Sustainable and Circular Economy

Packaging is fundamental to maintaining the quality of food, but its contribution with a negative footprint to the environment must be completely changed worldwide to reduce pollution and climate change. Innovative and sustainable packaging and new strategies of reutilization are necessary to reduce plastic waste accumulation, maintain food quality and safety, and reduce food losses and waste. The purpose of this chapter is to present innovations in food packaging for a sustainable and circular economy. First, to present the eco-design packaging approach as well as new strategies for recycled or recyclable materials in food packaging. Second, to show current trends in new packaging materials developed from the use of agro-industrial wastes as well as new methods of production, including 3D/4D printing, electrostatic spinning, and the use of nanomaterials.

Self-assembled carboxymethyl chitosan/zinc alginate composite film with excellent water resistant and antimicrobial properties for chilled meat preservation

A major way to reduce meat waste is to extend the shelf life of chilled meat with appropriate packaging. However, most of the packaging film cannot keep meat fresh because of its poor antibacterial and water resistance performance. In this paper, a composite film for chilled meat packaging was synthesized by simple self-assembly of zinc ions with chelating carboxyl groups. Introducing zinc ions into the composite system endows excellent water resistance and antibacterial properties to the film, which are demonstrated by the water vapor permeability and Escherichia coli and Staphylococcus aureus antibacterial tests. The as-prepared composite film also showed enhanced mechanical properties due to the formation of chelation bonds between zinc ions and carboxyl groups. Moreover, the chilled meat preservation test demonstrated the as-prepared composite film can significantly extend the shelf life of pork by five days, indicating its outstanding freshness preservation property. This work demonstrated a facile method to synthesize water-resistant and antimicrobial composite film, which can appear as an effective packaging material for chilled meat and offer a new idea to solve its short shelf-life problem.

Characterization and bio-functional performance of chitosan/poly (vinyl alcohol)/trans-cinnamaldehyde ternary biopolymeric films

Bioactive films of chitosan (CS)/polyvinyl alcohol (PVA)/trans-cinnamaldehyde (CIN) were prepared by co-blending, and the impact of varying concentrations (0.5, 1.0 and 1.5 %) of CIN on the physicochemical properties of the ternary films was investigated. The ATR/FT-IR analysis revealed that the bioactive film is modulated by Schiff base (C=N) and hydrogen-bond interactions of CS, PVA, and CIN. Inclusion of CIN into the film improved mechanical properties with tensile strength increased from 0.5 % (68.52 MPa) to 1.5 % (76.95 MPa). The presence of CIN within the CS/PVA film also remarkably affected oxygen permeability and improved light transmittance. Additionally, the water barrier and contact angle properties were improved with increasing CIN content. The morphology of the CIN-containing films appeared non-stratified and dense when observed by SEM and AFM. Moreover, spore germination and in vitro assays confirmed strong antifungal activity of the CIN-containing film against P. italicum (~90 %) and B. cinerea (~85 %). The ternary films also exhibited excellent antioxidant activity, as evidenced by DPPH radical scavenging activity (31.43 %) and ferric reducing power (OD700 nm = 0.172) at the highest CIN concentration tested. Thus, this bioactive CIN films are proposed as a versatile packaging material for the food industry.

Preparation of chitosan/Enoki mushroom foot polysaccharide composite cling film and its application in blueberry preservation

In this study, the composite cling film was prepared by solution casting method using chitosan and golden mushroom foot polysaccharide as substrates, and the structure and physicochemical indexes of the composite cling film were characterized by Fourier infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results showed that compared with single chitosan film, the composite cling film has better mechanical properties and antioxidant properties, and the barrier of UV light and water vapor is also stronger. Due to its high nutritional value, blueberry has a short shelf life due to its thin skin and poor storage resistance. Therefore, in this study, blueberry was used as the object of freshness preservation, and the single chitosan film group and the uncovered group were used as controls, and the weight loss, total bacterial colony, decay rate, respiration intensity, malondialdehyde content, hardness, soluble solids, titratable acid, anthocyanin content, and VC content of blueberry were used as freshness preservation indexes for experiments. The comprehensive results showed that the freshness preservation effect of the composite film group was significantly higher than that of the control group, with better antibacterial properties, antioxidant properties, etc., which could effectively delay fruit decay and deterioration, thus prolonging the shelf life, and thus the chitosan/Enoki mushroom foot polysaccharide composite preservation film has a high potential as a new freshness preservation material for blueberry.

Chitosan-pullulan films enriched with Artemisia annua essential oil: Characterization and application in grape preservation

Composite films were prepared using a flow casting method, with chitosan and pullulan as film-forming agents and Artemisia annua essential oil as the UV absorber. The utility of the composite films for preserving grape berries was assessed. The effect of the added Artemisia annua essential oil on the physicochemical properties of the composite film was investigated to determine the optimal amount of essential oil that should be added to the composite film. When the Artemisia annua essential oil content was 0.8 %, the elongation at break of the composite film increased to 71.25 ± 2.87 % and the water vapor transmission rate decreased to 0.378 ± 0.007 g‧mm/(m²‧h‧kpa). The transmittance of the composite film was almost 0 % in the UV region (200-280 nm) and <30 % in the visible light region (380-800 nm), reflecting the UV absorption by the composite film. Additionally, the composite film extended the storage time of the grape berries. Therefore, the composite film containing Artemisia annua essential oil may be a promising fruit packaging material.

Fabrication and characterization of polyvinyl alcohol/sodium alginate/zein/ chitosan bilayer film for dynamic visualization of pork quality

The development of real-time and convenient meat freshness indication technology is crucial to ensure food safety. A novel antibacterial visualized intelligent film was designed based on polyvinyl alcohol (PA), sodium alginate (SA), zein (ZN), chitosan (CS), alizarin (AL) and vanillin (VA) using layer-by-layer assembly (LBL) method for real-time and in situ monitoring of pork freshness. The fabricated film had various advantageous properties, including an excellent hydrophobicity with a water contact angle (WCA) of 91.59°, improved color stability, excellent water barrier properties and increased mechanical performance (TS = 42.86 MPa). The fabricated film also demonstrated effective antibacterial properties with a bacteriostatic circle diameter of 13.6 mm for Escherichia coli. Moreover, the film can perceive and visualize the antibacterial effect through color changes, enabling dynamic visual monitoring of the antibacterial effect. A good correlation (R² = 0.9188) between the color changes (ΔE) and total viable count (TVC) of pork was documented. Conclusively, fabricated multifunctional film improves the accuracy and versatility of freshness indication and had great potential for food preservation and freshness monitoring. The outcomes of this research provides a new perspective for the design and development of multifunctional intelligent films.

Recent trends in nanocomposite packaging films utilising waste generated biopolymers: Industrial symbiosis and its implication in sustainability

Uncontrolled waste generation and management difficulties are causing chaos in the ecosystem. Although it is vital to ease environmental pressures, right now there is no such practical strategy available for the treatment or utilisation of waste material. Because the Earth's resources are limited, a long-term, sustainable, and sensible solution is necessary. Currently waste material has drawn a lot of attention as a renewable resource. Utilisation of residual biomass leftovers appears as a green and sustainable approach to lessen the waste burden on Earth while meeting the demand for bio-based goods. Several biopolymers are available from renewable waste sources that have the potential to be used in a variety of industries for a wide range of applications. Natural and synthetic biopolymers have significant advantages over petroleum-based polymers in terms of cost-effectiveness, environmental friendliness, and user-friendliness. Using waste as a raw material through industrial symbiosis should be taken into account as one of the strategies to achieve more economic and environmental value through inter-firm collaboration on the path to a near-zero waste society. This review extensively explores the different biopolymers which can be extracted from several waste material sources and that further have potential applications in food packaging industries to enhance the shelf life of perishables. This review-based study also provides key insights into the different strategies and techniques that have been developed recently to extract biopolymers from different waste byproducts and their feasibility in practical applications for the food packaging business.

Hydrophobic, Sustainable, High-Barrier Regenerated Cellulose Film via a Simple One-Step Silylation Reaction

With the increasing importance of environmental protection, high-performance biopolymer films have received considerable attention as effective alternatives to petroleum-based polymer films. In this study, we developed hydrophobic regenerated cellulose (RC) films with good barrier properties through a simple gas-solid reaction via the chemical vapor deposition of alkyltrichlorosilane. RC films were employed to construct a biodegradable, free-standing substrate matrix, and methyltrichlorosilane (MTS) was used as a hydrophobic coating material to control the wettability and improve the barrier properties of the final films. MTS readily coupled with hydroxyl groups on the RC surface through a condensation reaction. We demonstrated that the MTS-modified RC (MTS/RC) films were optically transparent, mechanically strong, and hydrophobic. In particular, the obtained MTS/RC films exhibited a low oxygen transmission rate of 3 cm³/m² per day and a low water vapor transmission rate of 41 g/m² per day, which are superior to those of other hydrophobic biopolymer films.

Lignin-induced sacrificial conjoined-network enabled strong and tough chitosan membrane for food preservation

As a natural green polymer, chitosan is a promising material for plastic replacement. However, the mutually exclusive strength and toughness severely limit its commercial application, and the improved strength of chitosan-based materials is typically achieved at the expense of elongation or toughness. Herein, inspired by the existed multiple non-covalent interactions in biosynthesized fibers, we successfully fabricated a high-performance lignin/chitosan composite film by constructing sacrificial conjoined-network (hydrogen bonds, electrostatic interaction, etc.), which results in an impressive enhancement in tensile strength (50.2 MPa), elongation (73.6 %), and toughness (2.7 MJ/m³) simultaneously, much superior to the pure chitosan film. In addition, the composite film also demonstrates excellent UV resistance, thermal stability, low oxygen permeability (3.9 cm³/(m²·24h‧0.1 MPa)) and food preservation (with no negligible change for grape, apple, and cherry tomato after 5-10 days). Such developed lignin/chitosan with both components from biomass represents a promising alternative for plastic replacement.

Fabrication and characterization of waste fish scale-derived gelatin/sodium alginate/carvacrol loaded ZIF-8 nanoparticles composite films with sustained antibacterial activity for active food packaging

An environmental-friendly composite films containing waste fish scale-derived gelatin (FSG), sodium alginate (SA) and carvacrol loaded ZIF-8 (CV@ZIF-8) nanoparticles were designed and fabricated to develop active food packaging materials capable of sustained antibacterial activity. The microstructure and physicochemical properties of the FSG/SA/CV@ZIF-8 composite films were investigated. The incorporation of CV@ZIF-8 into FSG/SA matrix significantly enhanced the UV-light blocking and the elongation at break, improved water resistance and reduced water vapor permeability, and improved the thermal stability of composite film. The FSG/SA/CV@ZIF-8 film not only exhibited strong antioxidant activity with DPPH radical scavenging rate of 92.35 %, but also showed the satisfactory and long-acting antibacterial ability against E. coli and S. aureus due to slow release of CV from composite film. Strawberry preservation experiment revealed that FSG/SA/CV@ZIF-8 film decelerated the texture deterioration and retarded the growth of spoilage microorganism, resulting in the prolonged shelf-life of 8 days under ambient condition, indicating its promising application prospect in food preservation packaging.

Improved hydrophobicity, antibacterial and mechanical properties of polyvinyl alcohol/quaternary chitosan composite films for antibacterial packaging

Polyvinyl alcohol (PVA) and chitosan (CS) are attractive polymeric feedstocks for developing eco-environmental materials. In this work, a biodegradable and antibacterial film was developed based on PVA blending with different long-chain alkyl and different contents of quaternary chitosan through solution casting, in which quaternary chitosan not only acted as an antibacterial agent but also improved hydrophobicity and mechanical properties. A novel peak appeared at 1470 cm^-1 in Transform Infrared Spectroscopy (FTIR) and a new CCl bond spectral peak at 200 eV in X-ray photoelectron spectroscopy (XPS) spectra suggested that CS was successfully modified by quaternary. Besides, the modified films have better antibacterial effects against Escherichia (E. coli) and Staphylococcus (S. aureus) and present stronger antioxidant properties. Optical properties demonstrated that the light transmittance on both UV and visible light showed a decreasing trend with the increase of the quaternary chitosan contents. Whereas the composite films have enhanced hydrophobicity than PVA film. Furthermore, the composite films had higher mechanical properties, in which Young's modulus, tensile strength, and elongation at break were 344.99 MPa, 39.12 MPa, and 507.09 %, respectively. This research demonstrated that the modified composite films could extend the shelf of life on antibacterial packaging.

Development of a Halochromic, Antimicrobial, and Antioxidant Starch-Based Film Containing Phenolic Extract from Jaboticaba Peel

In this study, the antioxidant, antimicrobial, mechanical, optical, and barrier attributes of Solanum lycocarpum starch bio-based edible films incorporated with a phenolic extract from jaboticaba peel were investigated. Aiming to determine the effect of the polymers and the phenolic extract on the properties of the films, a three-factor simplex-lattice design was employed, and the formulation optimization was based on the produced films' antioxidant potential. The optimized formulation of the starch-PEJP film showed a reddish-pink color with no cracks or bubbles and 91% antioxidant activity against DPPH radical. The optimized starch-PEJP film showed good transparency properties and a potent UV-blocking action, presenting color variation as a function of the pH values. The optimized film was also considerably resistant and highly flexible, showing a water vapor permeability of 3.28 × 10-6 g m-1 h-1 Pa-1. The microbial permeation test and antimicrobial evaluation demonstrated that the optimized starch-PEJP film avoided microbial contamination and was potent in reducing the growth of Escherichia coli, Staphylococcus aureus, and Salmonella spp. In summary, the active starch-PEJP film showed great potential as an environmentally friendly and halochromic material, presenting antioxidant and antimicrobial properties and high UV-protecting activity.

Characterization and antioxidant properties of chitosan/ethyl-vanillin edible films produced via Schiff-base reaction

In this paper, chitosan/ethyl-vanillin (CS-EV) Schiff-base edible films with CS and EV at different concentrations and ratios were successfully prepared. The optical barrier properties, water contact angle, mechanical performance, water vapor transmission, antioxidant properties, thermal properties, and morphological structure of the films were compared. The results suggested that the tensile strength (TS) attained a maximum value of 64.63 MPa at a concentration of 4% EV. Moreover, water diffusion was prevented through the compact structure of the CS-EV edible film. Additionally, the two sides of the CS-EV film show different textures due to their different hydrophilicity/hydrophobicity. In particular, the films of CS possessed superior thermal stability, while those of CS-EV exhibited higher antioxidant activity.

Bio-separation of value-added products from Kraft lignin: A promising two-stage lignin biorefinery via microbial electrochemical technology

The most ubiquitous aromatic biopolymer in nature, lignin offers a promising foundation for the development of bio-based chemicals with wide-ranging industrial uses attributable to its aromatic structure. Lignin must first be depolymerized into smaller oligomeric and monomeric units at the initial stage of lignin bioconversion, followed by separation to recover valuable products. This study demonstrates an integrative biorefinery idea based on in-situ depolymerization of the lignin via microbial electro-Fenton reaction in a microbial peroxide-producing cell and recovery of the identified products i.e., phenolic or aromatic monomers by one step high throughput chromatography. The yield percentage of acetovanillone, ethylvanillin, and ferulic acid recovered from the depolymerized lignin using the integrative biorefinery strategy were 2.1 %, 9.1 %, and 9.04 %, respectively. These products have diverse industrial usage and can be employed as platform chemicals. The development of a novel system for efficient simultaneous lignin depolymerization and subsequent quality separation are demonstrated in this study.

Basella alba stem extract integrated poly (vinyl alcohol)/chitosan composite films: A promising bio-material for wound healing

Natural extract-based bio-composite material for wound healing is gaining much attention due to risk of infection and high cost of commercial wound dressing film causes serious problem on the human well-being. Herein, the study outlines the preparation of Poly (vinyl alcohol)/Chitosan/Basella alba stem extract (BAE) based bio-composite film through solvent casting technique and well characterized for wound healing application. Incorporation of BAE into Poly (vinyl alcohol)/Chitosan matrix has shown existence of secondary interactions confirmed by FT-IR analysis. Good morphology, thermal stability and significant improvement in flexibility (∼63.38 %) of the films were confirmed by SEM, TGA and Mechanical test results, respectively. Hydrophilic property (∼9.04 %), water vapor transmission rate (∼70.07 %), swelling ability (∼14.7 %) and degradation rate (∼14.04 %) were enhanced with increase in BAE content. In-vitro studies have shown good antibacterial activity against foremost infectious bacterial strains S. aureus and E. coli. Additionally, BAE integrated Poly (vinyl alcohol)/Chitosan film has amplified anti-inflammatory (∼79.38 %) property, hemocompatibility and excellent biocompatibility (94.9 %) was displayed by cytotoxicity results. Moreover, in-vitro scratch assay and cell adhesion test results illustrated prominent wound healing (96.5 %) and adhesion. Overall results of the present work proclaim that developed bio-composite film could be utilized as a biomaterial in wound care applications.

Effect of Plasticization on Stretching Stability of Poly(Vinyl Alcohol) Films: A Case Study Using Glycerol and Water

Adding small molecular plasticizers is the most common route to tailor the stretchability of poly(vinyl alcohol) (PVA). However, how the plasticization along with the nature of the plasticizer governs the structural homogeneity during stretching remains an open question to answer. Herein, two representative plasticizers, glycerol (GLY) and water, are chosen to endow the PVA films with ductility. It is found that large strain cavitations cause obvious stress whitening in the PVA/H₂ O films; on the contrary, most of the PVA/GLY films maintain transparent undergoing tensile deformation. Through a combination of experimental inspections and molecular dynamic simulation, it is revealed that partial water molecules that behave as free water will aggregate into microdomains, which serve as mechanical defects responsible for yielding voids. Whereas, the GLY plasticizer homogeneously disperses at a molecular level and interacts with PVA chains through strong hydrogen bonds. More interestingly, it is illustrated that the dispersion and bound states of plasticizers are closely related to the mechanical character of the plasticized PVA films. These findings offer new insight into the working mechanism of plasticization on the structural stability during stretching, and guide the design of PVA/plasticizer system to obtain excellent comprehensive mechanics.

Active Food Packaging Made of Biopolymer-Based Composites

Food packaging plays a vital role in protecting food products from environmental damage and preventing contamination from microorganisms. Conventional food packaging made of plastics produced from unrenewable fossil resources is hard to degrade and poses a negative impact on environmental sustainability. Natural biopolymers are attracting interest for reducing environmental problems to achieve a sustainable society, because of their abundance, biocompatibility, biodegradability, chemical stability, and non-toxicity. Active packaging systems composed of these biopolymers and biopolymer-based composites go beyond simply acting as a barrier to maintain food quality. This review provides a comprehensive overview of natural biopolymer materials used as matrices for food packaging. The antioxidant, water barrier, and oxygen barrier properties of these composites are compared and discussed. Furthermore, biopolymer-based composites integrated with antimicrobial agents-such as inorganic nanostructures and natural products-are reviewed, and the related mechanisms are discussed in terms of antimicrobial function. In summary, composites used for active food packaging systems can inhibit microbial growth and maintain food quality.

Humidity-/Sweat-Sensitive Electronic Skin with Antibacterial, Antioxidation, and Ultraviolet-Proof Functions Constructed by a Cross-Linked Network

Most electronic skins (e-skins) show unique performance or possess sensory functions. The raw materials used for their preparation are potentially toxic or harmful, and there may be problems such as poor compatibility between the conductive fillers and polymers. In this paper, a silver-loaded nanocomposite film (PVA/CMS/vanillin/nanoAg) was prepared by the in situ reduction method in a greener route. The mechanical properties of this nanocomposite film had improved with a tensile strength of 30.95 MPa, an elongation at break of 101.9%, and a Young's modulus of 10.62 MPa. In the composite matrix, a cross-linked network was constructed based on the coordination and hydrogen bonds, which was conducive to the stability of the reduced AgNPs and AgNWs. When applied as an e-skin in humidity/sweat sensors and wearable electronics, the nanocomposite film responds to humidity within 60 s and records the electric signals of human joint movements and skin sweating with a response range of 0-140% to strain at 93% RH. This kind of e-skin has excellent antibacterial and antioxidant activities and shows an outstanding ultraviolet-proof performance, which provides a greener promising reference route for the design of wearable e-skins to monitor the health and movements of humans.

A novel conversion strategy for organic compounds in waste liquid crystal displays based on the near/supercritical methanol process

Waste liquid crystal displays (LCD) contain a large number of organic compounds such as cellulose triacetate (CTA), poly(vinyl alcohol) (PVA), triphenyl phosphate (TPP), and liquid crystal (LC). It is important to recover organic compounds from waste LCD due to their value and environmental toxicity. However, it is challenging to recover organic compounds from waste LCD because of the heterogeneous mixture of glass, organics and metals contained therein. In this study, an environment-friendly near/supercritical methanol (NSCM) process was developed as a closed cycle technology for the conversion of organic compounds from waste LCD. The acid-base catalytic activity and nonpolar property of the NSCM could efficiently promote the conversion of organic compounds from waste LCD. TPP could be extracted below 200 °C in the NSCM process. Below 250 °C, the conversion ratio of organic compounds from waste LCD ranged from 5 % to 68 % due to the extraction or decomposition of TPP, LC, and PVA. The main products obtained at 250 °C included long-chain alcohols and alkanes with a similar composition to industrial liquid paraffin, which could be widely used in other industrial processes. Under the optimal operation parameters (300 °C, 30 min, and 1:20 g/ml), the conversion ratio of organic compounds could reach 98 % due to the efficient decomposition of CTA. The main products obtained included ketones and esters chemicals, which could be further used as a chemical feedstock. No secondary pollutant was generated in the whole process. The low-boiling methanol could easily be recycled, which could make the NSCM a clean process for the production of high value-added organic products from waste LCD.

A review: Silver–zinc oxide nanoparticles – organoclay-reinforced chitosan bionanocomposites for food packaging

Research on bionanocomposites has been developed, while its application as food packaging is still being explored. They are usually made from natural polymers such as cellulose acetate, chitosan (CS), and polyvinyl alcohol. Bionanocomposite materials can replace traditional non-biodegradable plastic packaging materials, enabling them to use new, high-performance, lightweight, and environmentally friendly composite materials. However, this natural polymer has a weakness in mechanical properties. Therefore, a composite system is needed that will improve the properties of the biodegradable food packaging. The aim of this mini-review is to demonstrate recent progress in the synthesis, modification, characterization, and application of bionanocomposites reported by previous researchers. The focus is on the preparation and characterization of CS-based bionanocomposites. The mechanical properties of CS-based food packaging can be improved by adding reinforcement from inorganic materials such as organoclay. Meanwhile, the anti-bacterial properties of CS-based food packaging can be improved by adding nanoparticles such as Ag and ZnO.

Thermomechanical characterization of bioplastic films produced using a combination of polylactic acid and bionano calcium carbonate

The present study focuses on the thermomechanical investigation of bioplastic firms produced from a combination of polylactic acid (PLA) and nano-calcium carbonated (nano-CaCO₃) synthesized from the Achatina Fulica snail shell. The bioplastic films fabricated with nano-CaCO₃ content ranging from 1 to 5 wt% were prepared using a solvent casting method. Thermal stability and degradation with temperature-dependent mechanical properties such as stiffness, storage modulus, and loss modulus of the developed bioplastic films were determined. The conformation changes in the functional group of the developed bioplastic films after incorporating nano-CaCO₃ were also investigated. It was observed that incorporating nano-CaCO₃ improved the thermal stability and temperature-dependent mechanical properties of neat PLA, regardless of the percentage weight added. An 85.67% improvement in thermal stability was observed. The temperature-dependent stiffness increased by 84%, whereas the storage modulus improved by 240%. On the other hand, loss modulus improved by 50% due to nano-CaCO₃ incorporation into PLA. The FTIR curves of bioplastic films incorporated with nano-CaCO₃ present insignificant conformation changes in the functional group of the resulting bioplastic films. This is presumable due to the compatibility of the matrix and the reinforcement. As a result, the resulting materials' thermal and temperature-dependent mechanical properties improved significantly, demonstrating that the developed bioplastic films could be used for package applications.

Development of Pectin and Poly(vinyl alcohol)-Based Active Packaging Enriched with Itaconic Acid and Apple Pomace-Derived Antioxidants

The production of active and biodegradable packaging materials is an emerging and efficient alternative to plastic packaging materials. By combining poly(vinyl alcohol) (PVA), pectin, and itaconic acid (IA), biodegradable and water-soluble packaging materials can be obtained that can also increase the shelf-life and quality of foodstuff. In the present study, the generated film-forming solutions were enriched with organic or phenolic extracts from apple by-products (apple pomace). These extracts possess an efficient antioxidant activity of 9.70 ± 0.08, and 78.61 ± 0.24 μM Trolox/100 g fresh weight, respectively. Furthermore, the lyophilization of these by-products increased the extract’s organic and phenolic content and the antioxidant activity to 67.45 ± 0.28 and 166.69 ± 0.47 μM Trolox/100 g fresh weight, respectively. These extracts influence the physical-chemical properties of the biofilm solutions by facilitating the polymerization process and thus positively influencing their viscosity. The resulting biofilms presented low water vapor permeability and reduced solubility in water. Adding IA and organic/phenolic compounds facilitates the resistance against intrinsic and extrinsic factors; therefore, they might be applicable in the food industry.