Development of antioxidant chitosan film with banana peels extract and its application as coating in maintaining the storage quality of apple

Chitosan-metal and metal oxide nanocomposites for active and intelligent food packaging; a comprehensive review of emerging trends and associated challenges

In recent years, significant advancements in biopolymer-based packaging have emerged as a response to the environmental challenges posed by traditional petroleum-based materials. The drive for sustainable, renewable, and degradable alternatives to fossil-based components in the packaging industry has led to an increased focus on chitosan, the second most abundant biopolymer after cellulose. Chitosan offers intrinsic properties such as biodegradability, biocompatibility, antimicrobial activity, excellent barrier and film-forming capabilities, positioning it as an ideal candidate for food packaging applications. However, limitations including inferior mechanical, thermal, barrier properties, and brittleness compared to conventional plastics have limiting its widespread adoption in the food packaging industry. Chitosan has been extensively utilized in various forms, particularly as nanocomposites incorporating metal nanoparticles, leading to chitosan-based nanocomposite films/coatings that synergistically combine the advantageous properties of both chitosan and metal nanoparticles. Through an in-depth analysis of the current research (primarily the last 5 years), this review delves into the physicochemical, mechanical, sensing, and antimicrobial properties of chitosan nanocomposite as an innovative food packaging material. This review will provide insights into the potential toxicity and environmental impact of nanoparticle migration, as well as the prospects and challenges associated with chitosan-metal/metal oxide nanocomposite films in the development of sustainable packaging solutions.

Self-healing packaging films/coatings for food applications; an emerging strategy

Food packaging (FP) plays a crucial role in maintaining food quality, and the integrity of FP is directly linked to its barrier properties, which ultimately affects the preservation ability of FP materials. Therefore, incorporation of self-healing (SH) properties has emerged as an intriguing approach to enhance the performance of FP materials. Materials possessing SH properties can sustain their integrity through dynamic covalent bonds and/or non-covalent interactions, thereby continuously preserving the barrier properties of FP materials. In this study, our focus lies in exploring SH materials for FP films/coatings. We provide a summary of the mechanisms underlying biopolymeric SH materials, discuss the preparation methods for biopolymeric SH FP films/coatings, and present the latest advancements in their application for food preservation. Finally, we outline the future opportunities and challenges associated with the application of SH materials in FP.

A review of bio-based dialdehyde polysaccharides as multifunctional building blocks for biomedical and food science applications

Food science and biomedical engineering are key disciplines related to human health, with the development of functional materials being an important research direction in both fields. In recent years, dialdehyde polysaccharides (DAPs), as green biopolymers, have become increasingly important in functional materials within food science and biomedical engineering. This work systematically summarizes the sources and properties of various DAPs, introduces their preparation methods and common DAP-based functional biomaterials, including hydrogels, scaffolds, films, coatings, nanoparticles, and nanofibers. Importantly, this work also reviews DAP applications in functional materials for food science and biomedical engineering, such as drug delivery, wound dressings, tissue engineering, food packaging films/edible coatings, food emulsions, antibacterial nanoparticles, and enzyme immobilization. Finally, the work briefly discusses the biosafety of DAPs. To conclude, this study provides a toolkit for developing functional materials in these fields and offers important reference value regarding the broad application of DAPs.

Preparation of polysaccharide-based films synergistically reinforced by tea polyphenols and graphene oxide

In this study, pectin (PE) composite films containing tea polyphenol (TP) and graphene oxide (GO) were developed. The effects of TP and GO on the appearance, structure, mechanical properties, barrier properties, hydrophobicity, and antioxidant properties of pure PE films were investigated. The results demonstrated that the addition of 1 % w/w TP and 1 % w/w GO increased the tensile strength (TS) and elongation at break (EB) of the composite films to 20.22 MPa and 34.18 %, respectively. Additionally, the water vapor permeability (WVP) was reduced to 0.67 ± 0.17 (×10-10 g-1s-1Pa-1), and both the moisture content and water contact angle were significantly decreased. Furthermore, the incorporation of TP enhanced the antioxidant properties of the composite films and demonstrated the slow-release capability of TP. Blueberry fruits packaged in PE-TP-GO film maintained an optimal appearance after eight days of storage at 25 °C, with a reduction in shrinkage index of approximately 29.4 % compared to those packaged in the PE film.

Effects of keto acid crosslinking on the structure and properties of chitosan based casted and hot-pressed films

Crosslinking is one of the most effective ways to enhance the performance of bio-based films, and suitable crosslinking agents are crucial for the enhancement. In this study, four α-ketoacids, namely glyoxylate, pyruvate, oxaloacetate, and α-ketoglutarate were used to crosslink chitosan at room temperature. The effects of crosslinking on the structure and properties of chitosan films were studied, and the reaction mechanism was explored. Fourier Transform Infrared spectroscopy and X-ray Photoelectron Spectroscopy indicated that ion attraction and Schiff base reactions occurred between keto acids and chitosan. Glyoxylate developed the most effective covalent crosslinking with chitosan, whereas α-ketoglutarate had the highest ionic crosslinking ratio. Keto acid crosslinking reduced the orderliness of chitosan, improved the uniformity of the film matrix and increased its UV-blocking capacity. Glyoxylate-crosslinked chitosan film demonstrated excellent tensile strength (160 MPa), water stability (water solubility about 11.71 %), and extremely low oxygen permeability (2.65 × 10-16 cm3·cm/cm-2·s-1· Pa-1). Despite the weakened thermal stability and water barrier property, glyoxylate crosslinking shows great potential for the preparation of high-strength and high‑oxygen-resistance chitosan films. Furthermore, the glyoxylate-crosslinked chitosan film could be produced by hot pressing and performed satisfactorily.

Development of eco-friendly chitosan films incorporated with pomelo peel (Citrus Paradisi cv. Changshanhuyou) extract and application to prolong the shelf life of grapes

Active packaging is an innovative technology that employs active materials to interact with the product and its environment, extending food shelf life. The aim of research was to develop a multifunctional film using pomelo (Citrus Paradisi cv. Changshanhuyou) peel extract (PPE) at concentrations of 5 %, 10 %, and 15 % as the active component, with chitosan (CS) serving as the primary carrier. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy confirmed the successful integration of PPE into the CS matrix. The effects of PPE on the anti-oxidant properties of the edible-films were evaluated to determine the optimal concentration for film production. Results showed that the 5 % PPE content enhanced film properties, including antioxidant and antibacterial activity. A subsequent study assessed the preservation effect of the films on grapes compared to untreated controls. Notably, the CSE2 film (5 % PPE) significantly reduced grape decay while maintaining pH, color, texture, and moisture within acceptable ranges over 16 days of storage at room temperature (26 °C ± 1). Findings showed that the potential of CSE2 film as an eco-friendly solution to reduce environmental pollution, minimize post-harvest losses, and extend grapes shelf life. Further research is needed to explore PPE effects on various foods and enhance composite edible films.

Emerging chitosan systems incorporated with polyphenols: Their applications in intelligent packaging, active packaging, and nutraceutical systems - A comprehensive review

Chitosan, a biodegradable anionic polysaccharide, has been increasingly investigated for food packaging and nutraceutical applications. In recent years, chitosan has been combined with polyphenols, a group of health promoting bioactive compounds, to enhance their physicochemical, functional, and biological properties. The synergistic functional attributes of chitosan and polyphenols have led to the development of several novel food packaging materials and nutraceuticals. Despite, several investigations being conducted on chitosan-polyphenol materials (e.g., films, coating, nanoparticles, complexes, emulsion gels), currently there is a lack of studies that comprehensively evaluate the combined effect of chitosan and polyphenol in development of both food packaging materials and nutraceuticals. Therefore, in this review, novel packaging materials and nutraceuticals developed employing chitosan-polyphenol in recent years (2018-2024) are thoroughly investigated. This review initiates with the source, production strategies, and techniques employed to improve the functionality of chitosan. Secondly, the findings associated with important intelligent packaging materials, including pH indicator, time-temperature indicator, and freshness indicator, developed using chitosan-polyphenol is investigated. Following that, the applications of chitosan-polyphenol materials in active food packaging (i.e., antimicrobial, antioxidant, oxygen scavenger, ethylene scavenger, and moisture scavenger) are explored. Notably, chitosan-based delivery systems that are employed to improve the chemical stability, bioaccessibility, and biological properties of polyphenols for nutraceutical applications are summarized. Finally, the challenges associated with the industrial application of chitosan-polyphenol materials are addressed. Overall, this review would benefit a wide range of scientists from food packaging to ingredient sectors by providing the current knowledge associated with chitosan-polyphenol materials.

Chitosan: A versatile polymer for enhancing plant bioactive accumulation, managing plant diseases, and advancing food preservation technologies

Chitosan is a versatile biopolymer composed of N-acetyl D-glucosamine and D-glucosamine units linked by β-(1→4) glycosidic bonds. It is known for its diverse biological applications, which include antimicrobial, antioxidant, antitumor, immunomodulatory, immunoadjuvant, and metal ion chelating abilities. Despite these benefits, the complexity of chitosan's structure limits its use in specific applications, particularly in scalability, solubility, and formulation stability. This review examines chitosan's role in food technology, agriculture, and tissue culture, focusing on its potential to enhance the accumulation of secondary metabolites and its applications in nanotechnology. A comprehensive search of databases, including PubMed, Scopus, and Google Scholar, was conducted to gather relevant literature. Chitosan is used in food technology to preserve seafood and meat, package them, and monitor degradation. Its role in improving crop productivity and plant disease management and promoting growth in both ex-vitro and in-vitro conditions has been discussed, as have chitosan-based nanoformulations as plant growth promoters and biocides. Further research could unlock chitosan's potential to enhance food security, environmental sustainability, and sustainable agriculture. Future research should be directed toward enabling chitosan's broader applications beyond food technology and agriculture. An integrated effort among academic institutions, research centres, and regulatory bodies is needed to bridge the gap between innovation and practical implementation. These efforts include joint research initiatives, policy framework development, capacity building, public-private partnerships, harmonization of standards, and fostering collaboration between industries and regulatory agencies. These efforts aim to validate new technologies, establish shared databases, streamline approval processes, and ensure research outcomes are translatable into regulatory and commercial frameworks.

Chitosan/water caltrop pericarp extract reinforced active edible film and its efficacy as strawberry coating for prolonging shelf life

This study focuses on developing and characterizing active and sustainable packaging films made from chitosan (CS), enriched with a novel bioactive extract sourced from water caltrop (Trapa bispinosa Roxb.) pericarp (WCPE). In this study, chitosan (1 % w/v) based biocomposite films were produced using varying concentrations of bioactive extracts (0,5,10,15 and 20 % w/w of CS) from water caltrop pericarp, obtained through ultrasound-assisted extraction. WCPE extract possess excellent antioxidant (89 ± 1.41 %), higher phenolics (120.48 ± 4.67 mg GAE g-1) and antimicrobial property. Similarly, developed biocomposite demonstrated superior UV barrier (OP600nm ∼4.30), lower swelling (21.43 ± 2.61 %), lower moisture content (17.15 ± 1.82 %), minimum water vapor permeability (1.28 ± 0.06 g m-1 day-1 Pa-1 (×10-10)), excellent antioxidant capacity (60.41 ± 1.52 % for DPPH and 70.80 ± 2.36 % for ABTS), greater phenolics content (168 ± 4.16 mg GAE/100 g) and good antimicrobial property. Additionally, all formulated coating solutions demonstrated biocompatibility (>85 % cell viability) with BHK-21 fibroblast cells. Finally, the CS-WCPE20 solution was evaluated for its practical use as an edible coating to preserve strawberry, under storage conditions of 20 ± 5 °C and 75 ± 5 % relative humidity. Developed coating successfully preserved quality attribute such as lower weight loss (∼17 %), higher texture (∼2.18 N), optimum TSS (∼8.44 % Brix), maximum antioxidant quality (∼50 % DPPH scavenging activity) and higher color and visual attribute upto 8 days at ambient temperature. Thus, the optimized formulation demonstrates significant potential for use as an active and intelligent packaging solution, effectively extending the shelf life of fruits and vegetables.

Chemically modified chitosan as a functional biomaterial for drug delivery system

Chitosan is a natural polymer that can degrade in the environment and support green chemistry. It displays superior biocompatibility, easy access, and easy modification due to the reactive amino groups to transform or improve the physical and chemical properties. Chitosan can be chemically modified to enhance its properties, such as water solubility and biological activity. Modified chitosan is the most effective functional biomaterial that can be used to deliver the drugs to the targeted site. With diverse and versatile characteristics, it can be fabricated into various drug delivery systems such as membranes, beads, fibers, microparticles, composites, and scaffolds, for different drug delivery methods. Integrating nanotechnology with modified chitosan enhanced the delivery attributes of antibacterial, antifungal, antiviral, anticancer, anti-inflammatory, protein/peptides, and nucleic acids for intended use toward desired therapeutic outcomes. The review brings out an overview of the research regarding drug delivery systems utilizing modifying chitosan detailing the properties, functionality, and applications.

Enhancing fruit preservation with sodium alginate films incorporating propolis extract and graphene oxide

In this work, sodium alginate (SA) composite films containing propolis extract (PRO) and graphene oxide (GO) were developed. Subsequently, the effects of PRO and GO on different properties of SA composite films were studied, and the films were characterized by scanning electron microscopy, fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. The PRO release properties and fruit preservation performance of the developed composite films were also investigated. The results showed that the incorporation of PRO resulted in a 51.16% increase in tensile strength. The simultaneous incorporation of PRO and GO reduced water vapor permeability (WVP) by 22.56% compared to the SA film. The temperatures at which the SA/GO/PRO film lost 5% of its weight were 8.0°C higher than those of the SA film. The incorporation of GO into the SA/PRO composite film also modulates the release of PRO. Furthermore, the incorporation of PRO and GO improved the tensile strength of the SA film, as reflected in the microstructure of the films. The reduced WVP of the SA composite film allowed the packaged blueberries to exhibit less weight loss and shrinkage, thereby prolonging their shelf life.

Exploring the Potential of Chitosan-Phytochemical Composites in Preventing the Contamination of Antibiotic-Resistant Bacteria on Food Surfaces: A Review

The escalating presence of antibiotic-resistant bacteria (ARB) in food systems presents a pressing challenge, particularly in preventing contamination and ensuring food safety. Traditional sanitation methods, such as cooking and chemical disinfectants, provide effective means to reduce ARB, yet there is a growing need for additional preventive measures directly on food surfaces. This review explores the potential of chitosan-phytochemical composites (CPCs) as surface coatings to prevent the initial contamination of food by ARB, thereby offering a novel complementary approach to conventional food safety practices. Chitosan, combined with active plant-derived metabolites (phytochemicals), forms composites with notable antibacterial and antioxidant properties that enhance its protective effects. We examine CPC synthesis methodologies, including chemical modifications, free radical-induced grafting, and enzyme-mediated techniques, which enhance the stability and activity of CPCs against ARB. Highlighting recent findings on CPCs' antibacterial efficacy through minimum inhibitory concentrations (MIC) and zones of inhibition, this review underscores its potential to reduce ARB contamination risks on food surfaces, particularly in seafood, meat, and postharvest products. The insights provided here aim to encourage future strategies leveraging CPCs as a preventative surface treatment to mitigate ARB in food production and processing environments.

Recent functionality developments of carboxymethyl chitosan as an active food packaging film material

In recent years, environmental concerns regarding the persistence of petroleum-based plastic food packaging have increased, prompting the exploration of biopolymer alternatives. Carboxymethyl chitosan (CMCS), a derivative of chitosan, exhibits superior water-soluble film properties, making it an ideal material for degradable food packaging applications. This study comprehensively examines the synthesis methods and properties of CMCS, with a particular emphasis on recent advancements in CMCS-based food packaging films. Various functionalized CMCS-based food packaging films, including coblended, nanoparticle composite, plant extract composite, and cross-linked films, were reviewed. The practical applications of CMCS-based food packaging films and edible coatings in food preservation are also showcased. This study emphasizes that the notable compatibility of CMCC with a range of polymers and additives has facilitated the development of multifunctional packaging films. These innovations, including antibacterial, antioxidant, and smart-indicating variants, have demonstrated remarkable efficacy in preserving fruits, aquatic products, poultry, and other perishable goods.

Truxillic calcium supramolecular skeleton fortified pH responsive and biodegradable alginate hydrogel films promoting fruit preservation

This work presented a unique alginate hydrogel film fortified by truxillic calcium skeleton with notable physicochemical and mechanical properties, as well as the promising application in fruit preservation. A series of truxillic‑calcium-alginate (CBDA-Ca/SA) films were prepared. It was found that CBDA-10-Ca/SA can block over 50 % of UV-visible light. The maximum breaking strengths of (6 % CBDA-1-Ca)/SA and (2 % CBDA-10-Ca)/SA are 82 MPa and 79 MPa, about twice that of Ca/SA. CBDA-11-Ca/SA showed the highest WVP of 2.18 × 10-10 g ∙ m-1 ∙ s-1 ∙ Pa-1 and CBDA-10-Ca showed the best performance in reducing the OTR of the films by 4.1× 10-5 cm3 ⸱cm ⸱ m-2 ⸱ 24 h-1 ⸱ Pa-1. With water absorption ranging from 3480 % in an acidic environment to 9520 % in an alkaline environment, the CBDA-10-Ca/SA film demonstrated exceptional pH responsiveness. The degradation rate of all films was around 70 % after four weeks of burial under the soil. The above studies indicate that polyphenols can not only act as "hooks" to grasp Ca2+ to form supramolecular skeleton structure improving the mechanical strength of SA-based films, but also act as active components to endure the functional properties of SA-based films with antibacterial and antioxidant properties.

Edible Coating for Fresh-Cut Fruit and Vegetable Preservation: Biomaterials, Functional Ingredients, and Joint Non-Thermal Technology

This paper reviews recent advances in fresh-cut fruit and vegetable preservation from the perspective of biomacromolecule-based edible coating. Biomaterials include proteins, polysaccharides, and their complexes. Compared to a single material, the better preservation effect was presented by complexes. The functional ingredients applied in the edible coating are essential oils/other plant extracts, metals/metal oxides, and organic acids, the purposes of the addition of which are the improvement of antioxidant and antimicrobial activities and/or the mechanical properties of the coating. The application of edible coating with other preservation technologies is an emerging method, mainly including pulsed light, short-wave ultraviolet, modified atmosphere packaging, ozonation, and γ-irradiation. In the future, it is crucial to design coating formulations based on preservation goals and sensory characteristics. The combination of non-thermal preservation technology and edible coating needs to be strengthened in research on food preservation. The application of AI tools for edible coating-based preservation should also be focused on. In conclusion, edible coating-based preservation is promising for the development of fresh-cut fruits and vegetables.

Improving properties of chitosan/polyvinyl alcohol films using cashew nut testa extract: potential applications in food packaging

Cashew nut testa, a by-product of cashew nut processing, is abundant in phenolic compounds and exhibits strong antioxidant properties, making it a potential additive for enhancing the antioxidant properties of biodegradable films used in food packaging. This study explores the fabrication of biodegradable chitosan/polyvinyl alcohol films incorporating varying concentrations of cashew nut testa extract (CNTE; 0, 1, 2 and 3% v/v) and evaluates their physical, structural, mechanical, optical and antioxidant properties. The results demonstrate that increasing extract concentration generally increased the thickness, tensile strength, Young's modulus, thermal stability and antioxidant capacity of the films, while reducing the moisture content, swelling degree, elongation at break, and light transmittance. Specifically, the film with 3% extract showed approximately 11% lower moisture content and 31% lower swelling degree compared with the plain film. It also displayed the highest tensile strength and Young's modulus at 28.63 and 147.35 MPa, respectively. Microstructural analysis revealed that the incorporation of CNTE resulted in a smoother and slightly denser film structure. Antioxidant activity, determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, was not detected in the plain film but increased with increasing extract concentration. The film with 3% CNTE exhibited the highest antioxidant activity of 58.93 µmol Trolox equivalents (TE) g-1 film. This study highlights the potential of CNTE as an effective edible additive for developing antioxidant and ultraviolet barrier films with improved mechanical strength and water resistance for food packaging applications.

A novel ε-polylysine-reinforced pullulan/curdlan-active film for an efficient preservation of fresh-cut fruit and vegetable

In this study, a novel active film was developed by employing ε-polylysine (ε-PL) as a filler in pullulan/curdlan (P/CD) composite film (P/CD/ε-PL). The results showed that the structure of P/CD films was more uniform and denser compared to pullulan films, due to the good compatibility and intermolecular interaction between them. Among P/CD films, P/CD 6:1 film showed improved hydrophobicity, mechanical and barrier properties, and thermal stability, thereby selecting it for further use. Thereafter, the addition of ε-PL further enhanced the structural and physicochemical properties of prepared P/CD/ε-PL composite films, especially for P/CD/2.5%ε-PL composite film. It exhibited improved ultraviolet barrier (about 80% at 200-400 nm), antibacterial activity (>90% against Staphylococcus aureus and Escherichia coli), and anti-fog properties (clearly visible and transparent background). Furthermore, P/CD/2.5%ε-PL composite film exerted its preservation effect on fresh-cut peppers and kiwis during storage, delaying the softening, consumption of soluble solids, and deterioration. Therefore, the developed P/CD/2.5%ε-PL composite film provided promising applications of active packing film. Practical Application: Fresh-cut fruits and vegetables are prone to deteriorate during storage, and active packaging films play a crucial role in retaining their quality. This study was conducted to prepare a composite film by blending pullulan, curdlan, and ε-PL and explore its structural, physicochemical, and functional properties, further verifying the preservation effect on fresh-cut peppers and kiwis. Compared to polyethylene film, the P/CD/2.5%ε-PL composite film delayed the softening, consumption of soluble solids, and deterioration of fresh-cut peppers and kiwis during storage. It provides a new perspective on the preservation of fresh-cut fruits and vegetables.

Myrrh Oleo-Gum Resin as a Functional Additive in Pectin and κ-Carrageenan Composite Films for Food Packaging

Myrrh oleo-gum-resin (MOGR) is a natural substance that has a rich history of medicinal use due to its anti-inflammatory, antimicrobial, and antioxidant properties. The present study reports on the fabrication and assessment of pectin and K-carrageenan composite films infused with varying proportions (0.3%, 0.5%, and 0.7%) of MOGR. Morphological analysis of the film samples was conducted using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The results indicated that the introduction of MOGR led to a notable increase in surface roughness. The SEM micrographs of the films showed that the MOGR addition had an important effect on the microstructure of the film. The surface hydrophobicity of the MOGR-loaded films increased, as confirmed by the rise in the contact angle. Moreover, there was an increase in the thickness (0.062 ± 0.004-0.095 ± 0.006 mm) and opacity (1.24 ± 0.07-9.41 ± 0.24) of the films with the addition of MOGR; however, tensile strength (7.30 ± 0.50-4.92 ± 0.34 MPa), elongation at break (32.41% ± 1.0%-29.70% ± 0.24%), and barrier properties decreased. Additionally, a rise in MOGR concentration corresponded to a rise in overall color difference ΔE (0.77 ± 0.03-5.09 ± 0.49) of the films. Notably, the incorporation of MOGR led to an increase in the antioxidant activity of the composite films, indicating potential applications in functional packaging materials.

Preparation and characterization of polyvinyl alcohol/pullulan/ZnO-Nps composite film and its effect on the postharvest quality of Allium mongolicum Regel

Allium mongolicum Regel is prone to rapid senescence and quality deterioration during postharvest storage. Herein, polyvinyl alcohol/pullulan/ZnO nanoparticles (PVA/PUL/ZnO-Nps) composite films were prepared via solution casting and studied to analyze the effects of ZnO-Nps on the PVA/PUL film matrix. Results revealed that the incorporation of suitable ZnO-Nps effectively reduced the light transmittance, improved water contact angle, water vapor permeability, and mechanical properties of the composite films, as well as enhanced their antimicrobial activity. The composite films were used for the postharvest preservation of A. mongolicum Regel. Results revealed that the PVA/PUL/ZnO-Nps film effectively reduced malondialdehyde accumulation content, superoxide radical generation rate, hydrogen peroxide content, improve the activity of related enzymes, and extend the storage time compared with that of polyethylene films. Therefore, the PVA/PUL/ZnO-Nps film can be used as a novel packaging material for the postharvest preservation of A. mongolicum Regel.

Strong, tough self-healing multi-functional sodium alginate-based edible composite coating for banana preservation

Edible coatings are a new green technology for preventing the rotting of fruits and extending their shelf lives. However, during storage, respiratory processes can generate large amounts of water, causing the dissolution of these coating. Furthermore, these coating can be mechanically damaged. Therefore, the development of strong, tough, waterproof and self-healing edible coatings is highly desirable. Herein, gluconolactone was slowly oxidized to generate gluconic acid, which was further used to protonate amino groups in wheat gluten (WG), forming strong electrostatic interactions, hydrogen bonds and ester bonds between soy hull nanocellulose (SHNC) and sodium alginate (SA). The introduction of WG and SHNC improved the mechanical strength, hydrophobicity and water retention of the composite film from 28 MPa, 33.2° ± 1.18° and 19.43° ± 0.83° to 60 MPa, 45.13° ± 1.53° and 41.47° ± 0.96°, respectively. Further, the composite film exhibited excellent self-healing, UV resistance and gas-barrier properties. Banana preservation experiments showed that at 25 °C and 50 % RH, the composite coating effectively slowed the mass loss and softening of bananas, delayed the browning of banana peels and ripening of fruit pulp, and extended the shelf life of bananas to 7 days. Therefore, this study provides a new perspective for the preparation of a new, strong, tough, waterproof and self-healing multi-functional edible coating with high potential for the preservation of perishable fruits.

Effect of film-forming solution pH on the mechanical, barrier, and biological characteristics of chitosan/Piper betel L. leaf extract coating film for mango preservation

The present work aimed to investigate the effect of film-forming solution pH on characteristics of chitosan (CH) - Piper betel L. leaf extract (PBe) coating films and their potential applications in mango preservation. The coating films were fabricated from CH-PBe solutions in the pH range of 3-5 using a solvent evaporation technique. The analysis results (DSC and FTIR) demonstrate higher miscibility, better compatibility, and tighter intermolecular interactions between CH and active compounds in the film matrix prepared at low pH. The mechanical and barrier properties of the CH-PBe film significantly decreased with increasing pH value. Varying the film-forming pH insignificantly affected the antioxidant activity and antibacterial inhibition against Staphylococcus aureus (Gram-positive) of the resultant films. However, Escherichia coli (Gram-negative) was less vulnerable to the blend film prepared at the higher pH medium. The coating solution at pH 4 proved suitable for preserving 'Tu Quy' mangoes, according to the observation of color changes, accumulated decay rate, respiration rate, ripening index, and other related factors. The findings of this work reveal the importance of pH control in producing CH-PBe coating films for mango preservation and provide more insights into pH-affected interactions between CH matrix and polyphenols in PBe.

A comprehensive review of chitosan-based functional materials: From history to specific applications

Chitosan (CTS), a natural biopolymer derived from chitin, has garnered significant attention owing to its potential chemical, biological, and physical properties, such as biocompatibility, bioactivity, and biosafety. This comprehensive review traces the historical development of CTS-based materials and delves into their specific applications across various fields. The study highlights the evolution of CTS from its initial discovery to its current state, emphasizing key milestones and technological advancements that have expanded its utility. Despite the extensive research, the synthesis and functionalization of CTS to achieve desired properties for targeted applications remain a challenge. This review addresses current problems such as the scalability of production, consistency in quality, and the environmental impact of extraction and modification processes. Additionally, it explores the novel applications of CTS-based materials in biomedicine, agriculture, environmental protection, and food industry, showcasing innovative solutions and future potentials. By providing a detailed analysis of the current state of CTS research and identifying gaps in knowledge, this review offers a valuable resource for researchers and industry professionals. The novelty of this work lies in its holistic approach, combining historical context with a forward-looking perspective on emerging trends and potential breakthroughs in the field of CTS-based functional materials. Therefore, this review will be helpful for readers by summarizing recent advances and discussing prospects in CTS-based functional materials.

Gelatin-chitosan interactions in edible films and coatings doped with plant extracts for biopreservation of fresh tuna fish products: A review

The preservation of tuna fish products, which are extremely perishable seafood items, is a substantial challenge due to their instantaneous spoilage caused by microbial development and oxidative degradation. The current review explores the potential of employing chitosan-gelatin-based edible films and coatings, which are enriched with plant extracts, as a sustainable method to prolong the shelf life of tuna fish products. The article provides a comprehensive overview of the physicochemical properties of chitosan and gelatin, emphasizing the molecular interactions that underpin the formation and functionality of these biopolymer-based films and coatings. The synergistic effects of combining chitosan and gelatin are explored, particularly in terms of improving the mechanical strength, barrier properties, and bioactivity of the films. Furthermore, the application of botanical extracts, which include high levels of antioxidants and antibacterial compounds, is being investigated in terms of their capacity to augment the protective characteristics of the films. The study also emphasizes current advancements in utilizing these composite films and coatings for tuna fish products, with a specific focus on their effectiveness in preventing microbiological spoilage, decreasing lipid oxidation, and maintaining sensory qualities throughout storage. Moreover, the current investigation explores the molecular interactions associated with chitosan-gelatin packaging systems enriched with plant extracts, offering valuable insights for improving the design of edible films and coatings and suggesting future research directions to enhance their effectiveness in seafood preservation. Ultimately, the review underscores the potential of chitosan-gelatin-based films and coatings as a promising, eco-friendly alternative to conventional packaging methods, contributing to the sustainability of the seafood industry.

Transforming Agro-Industrial Waste into Bioplastic Coating Films

Addressing the environmental impact of agro-industrial waste, this study explores the transformation of banana, potato, and orange peels into bioplastics suitable for thin coating films. We prepared six extracts at 100 g/L, encompassing individual (banana peel, BP; orange peel, OP; and potato peel, PP) and combined [BP/OP, BP/PP, and BP/OP/PP] formulations, with yeast mold (YM) medium serving as the control. Utilizing the spin-coating method, we applied 1 mL of each sample at 1000 rpm for 1 min to create the films. Notably, the OP extract demonstrated a twofold increase in bioplastic yield (860.33 mg/L) compared to the yields of BP (391.43 mg/L), PP (357.67 mg/L), BP/OP (469.40 mg/L), BP/PP (382.50 mg/L), BP/OP/PP (272.67 mg/L), and YM (416.33 mg/L) extracts. Atomic force microscopy analysis of the film surfaces revealed a roughness under 8 nm, with the OP extract recording the highest at 7.0275 nm, whereas the BP/OP mixture exhibited the lowest roughness at 0.2067 nm and also formed the thinnest film at 6.5 nm. With R2 trend values exceeding 0.9950, the films exhibited water vapor permeability values ranging from 3.05 × 10-3 to 4.44 × 10-3, with the OP film being the least permeable and the BP/PP films the most permeable. The OP film demonstrated the lowest solubility in both water and ethanol with values of 64.71 and 1.05%, respectively. The solubilities of all films were above 60% in water and below 4% in ethanol. Furthermore, the films exhibited antimicrobial efficacy against both Gram-positive and Gram-negative bacteria. Our findings confirm the potential of utilizing banana, orange, and potato peels as viable substrates for eco-friendly bioplastics in thin-film applications.

Antimicrobial guar gum films optimized with Pickering emulsions of zein-gum arabic nanoparticle-stabilized composite essential oil for food preservation

In this study, composite essential oil Pickering emulsion stabilized with zein-gum arabic (GA) nanoparticles (ZGCEO) was prepared to improve the characteristics of guar gum (GG) films. ZGCEO exhibited commendable stability and compatibility with GG, while leading to a noticeable improvement in the light barrier (from 3.98 A mm-1 to 17.09 A mm-1) and water vapor barrier characteristics of GG films, concomitantly mitigating their hydrophilic nature, with decreasing moisture content (from 17.70 % to 10.50 %), water solubility (from 84.41 % to 71.79 %), water vapor permeability (from 5.64 × 10-11 g (m s Pa)-1 to 4.97 × 10-11 g (m s Pa)-1), and an increasing water contact angle (from 69.8° to 94.2°). The addition of 2 % ZGCEO yielded a notable increase in the tensile strength of the GG-ZGCEO films, but the elongation at break decreased with increasing ZGCEO concentration. Moreover, the incorporated ZGCEO demonstrated outstanding antioxidant and antimicrobial characteristics, featuring a slow-release behavior of essential oil. The GG-ZGCEO coating also showed an excellent preservation effect in pork and "Huangguan" pears during storage. Collectively, we substantiated the efficacy of ZGCEO in augmenting the functional attributes of GG films, thereby establishing their potential utility as antimicrobial packaging materials conducive to food preservation.

Preparation of multi-barrier and multi-functional paper-based materials by chitosan, ethyl cellulose and green walnut husk biorefinery products for sustainable food packaging

The growing interest in paper-based materials for packaging is driven by their renewable and eco-friendly characteristics. However, their poor barrier performance against water, oil, and gas limits their application in the food packaging industry. In this study, we developed a simple dual-layer coating method to create water- and oil-repellent, gas barrier, antioxidant, and antibacterial paper-based materials using naturally-derived materials, including chitosan (CS), ethyl cellulose (EC), and cascade biorefinery products from green walnut husk (GWHE and CNC). The bottom CS/CNC oil-resistant coating and the top EC/GWHE water-resistant coating were applied to the paper surface. The synergistic effect of these coatings enhances the gas barrier and imparts functional properties to the paper. Compared to uncoated paper, the dual-layer-coated paper demonstrated a 239.1 % increase in tensile index, a higher kit rating value of 12/12, a lower Cobb 60 value of 3.21 mg/m2, a 44.0 % decrease in water vapor permeability (WVP), and a 90.7 % reduction in air permeability (AP). Additionally, this coated paper exhibited good antioxidant and antibacterial properties and favorable biodegradability. This study provides novel insights into the valorization of GWH waste and presents a sustainable strategy for producing high-performance paper-based materials for food packaging applications.

Effect of metal cation crosslinking on the mechanical properties and shrimp freshness monitoring sensitivity of pectin/carboxymethyl cellulose sodium/anthocyanin intelligent films

Although many preparation methods have been reported so far, it is still a great challenge for intelligent packaging films with both excellent mechanical properties and very high sensitivity. Herein, we report a facile method to prepare performance-enhanced pectin (PC)/carboxymethyl cellulose sodium (CMC)/anthocyanins (ACNs)/metal ion films by crosslinking with metal ions (Zn2+, Mg2+ and Ca2+). Cross-linking reaction between PC/CMC and metal ions significantly improved water resistance and mechanical properties of composite films (P < 0.05). Even at high relative humidity (RH = 84 %), cross-linking of Ca2+, Mg2+, and Zn2+ significantly increased the tensile index of the films by 1.37, 1.41, and 1.52 times (P < 0.05), respectively. Moreover, the complexation of metal ions/polysaccharides with ACNs reduced the decomposition rate of ACNs, improved the storage stability and antioxidant capacity of ACNs, and also increased the sensitivity of the colorimetric response of the indicator films in monitoring shrimp freshness. Thus, with this high sensitivity, the Red, Green and Blue (RGB) values of the films can be determined using a mobile phone application to monitor shrimp safety in real time. These results suggest that ACNs-metal cation-polysaccharide composite films have great potential for smart packaging applications.

Application of seed mucilage as functional biopolymer in meat product processing and preservation

Meat products consumption is rising globally, but concerns about sustainability, fat content, and shelf life. Synthetic additives and preservatives used for extending the shelf life of meat often carry health and environmental drawbacks. Seed mucilage, natural polysaccharides, possesses unique functional properties like water holding, emulsifying, and film forming, offering potential alternatives in meat processing and preservation. This study explores the application of seed mucilage from diverse sources (e.g., flaxseed, psyllium, basil) in various meat and meat products processing and preservation. Mucilage's water-holding and emulsifying properties can potentially bind fat and decrease the overall lipid content in meat and meat-based products. Moreover, antimicrobial and film-forming properties of mucilage can potentially inhibit microbial growth and reduce oxidation, extending the shelf life. This review emphasizes the advantages of incorporating mucilage into processing and coating strategies for meat and seafood products.

Effect of different types of electrolyzed water on drying characteristics and quality of Spondias dulcis in oven drying

Due to its less adverse impact on the environment as well as human health, electrolyzed water, a non-thermal method, has been recognized to be a promising alternative as a new disinfectant for the food industry, which does not change odor, texture, and flavor of foods. Spondias dulcis fruit is rich in bioactive compounds, vitamins and minerals, which are known to have many beneficial effects on health. Fresh S. dulcis has a short shelf life and drying is an option to preserve the fruit. In this study, the effects of electrolyzed water treatment on the quality characteristics of dried S. dulcis were investigated. Slices of fruit treated with four different electrolyzed waters (Anolyte NaCl, Catholyte NaCl, Anolyte Na2CO3, and Catholyte Na2CO3) were dried in a conventional oven at 70 °C. Color, Browning index, antioxidant characteristics, texture profile, rehydration capacity, pH, and Fourier transform infrared spectroscopy analyzes of dried S. dulcis were performed. The samples treated with electrolyzed water prior to drying showed higher antioxidant activity (59.46 ± 0.09), total phenolic content (287.00 ± 1.76), and rehydration capacity (4.52 ± 0.05) compared to the control samples. The findings of the current study showed that electrolyzed water treatment could prevent the browning of dried S. dulcis fruits and preserve bioactive compounds as well as chemical properties.

Impact of Antioxidant-Enriched Edible Gel Coatings and Bio-Based Packaging on Cherry Tomato Preservation

This research investigates the effects of using edible gel coatings and bio-based packaging materials on extending the shelf life of cherry tomatoes. Two edible gel coatings (guar gum and guar gum +5% of a lemon (Citrus limon (L.) Osbeck pomace extract obtained in the research laboratory) were applied on cherry tomatoes, then they were packaged in bio-based materials (cellulose tray + PLA lid). Guar gum, glycerol, sorbitol, extra virgin olive oil, and tween 20 were used in coating formulation. Uncoated tomatoes packed in bio-based materials and conventional plastic (PET trays + lid) were tested as a control. Samples were stored for 45 days at 20 °C and their quality parameters were evaluated. Coated tomatoes maintained firmness and weight, and the enriched coated samples showed a significant increase in phenol content, derived from the antioxidant extract. Samples packed in PET showed a sensory unacceptability (<4.5) after 45 days correlated with a greater decline in firmness (from 10.51 to 5.96 N) and weight loss (from 7.06 to 11.02%). Therefore, edible gel coating and bio-based packaging proved to be effective in maintaining the overall quality of cherry tomatoes for 45 days, offering a promising approach to reduce plastic polymer use and food waste.

Tuning the Properties of Xylan/Chitosan-Based Films by Temperature and Citric Acid Crosslinking Agent

Petroleum-based food packaging causes environmental problems such as waste accumulation and microplastic generation. In this work, biobased films from stable polyelectrolyte complex suspensions (PECs) of xylan and chitosan (70 Xyl/30 Ch wt% mass ratio), at different concentrations of citric acid (CA) (0, 2.5, 5, 7.5 wt%), were prepared and characterized. Films were treated at two temperatures (135 °C, 155 °C) and times (30 min, 60 min) to promote covalent crosslinking. Esterification and amidation reactions were confirmed by Fourier Transform Infrared Spectroscopy and Confocal Raman Microscopy. Water resistance and dry and wet stress-strain results were markedly increased by thermal treatment, mainly at 155 °C. The presence of 5 wt% CA tended to increase dry and wet stress-strain values further, up to 88 MPa-10% (155 °C for 60 min), and 5.6 MPa-40% (155 °C for 30 min), respectively. The UV-blocking performance of the films was improved by all treatments, as was thermal stability (up to Tonset: 230 °C). Contact angle values were between 73 and 84°, indicating partly wettable surfaces. Thus, thermal treatment at low CA concentrations represents a good alternative for improving the performance of Xyl/Ch films.

The dual function of calcium ion in fruit edible coating: Regulating polymer internal crosslinking state and improving fruit postharvest quality

The edible coating is proved to be a convenient approach for fruit preservation. Among these published explorations, naturally sourced macromolecules and green crosslinking strategies gain attention. This work centers on edible coatings containing Ca2+ as crosslinker for the first time, delving into crosslinking mechanisms, include alginate, chitosan, Aloe vera gel, gums, etc. Additionally, the crucial functions of Ca2+ in fruit's quality control are also elaborated in-depth, involving cell wall, calmodulin, antioxidant, etc. Through a comprehensive review, it becomes evident that Ca2+ plays a dual role in fruit edible coating. Specifically, Ca2+ constructs a three-dimensional dense network structure with polymers through ionic bonding. Moreover, Ca2+ acts directly with cell wall to maintain fruit firmness and serve as a second messenger to participate secondary physiological metabolism. In brief, coatings containing Ca2+ present remarkable effects in preserving fruit and this work may provide guidance for Ca2+ related fruit preservation coatings.

A review of starch/polyvinyl alcohol (PVA) blend film: A potential replacement for traditional plastic-based food packaging film

In recent years, the development of environmentally friendly packaging materials using biodegradable polymers has emerged as a key challenge for scientists and consumers in response to resource depletion and environmental issues caused by plastic packaging materials. Starch and polyvinyl alcohol (PVA) are being recognized as excellent candidates for producing biodegradable food packaging films. Polymer blending has emerged as a practical approach to overcome the limitations of biopolymer films by developing films with unique properties and enhancing overall performance. This review briefly introduces the molecular structure and properties of starch and PVA, summarizes the common preparation methods and properties of starch/PVA blend films, and focuses on different strategies used to enhance starch/PVA blend films, including nanoparticles, plant extracts, and cross-linking agents. Additionally, this study summarizes the application of starch/PVA blend films as active and smart packaging in food preservation systems. This study demonstrates that starch and PVA blends have potential in manufacturing biodegradable food films with excellent properties due to their excellent compatibility and intermolecular interactions, and can be used as packaging films for a variety of foods to extend their shelf life.

Investigation of interactions between Jiuzao glutelin with resveratrol, quercetin, curcumin, and azelaic and potential improvement on physicochemical properties and antioxidant activities

The interactions among small molecular functional components (FCTs) within a food matrix have become a focal point for enhancing their stability and bioactivities. Jiuzao glutelin (JG) is a mixed plant protein within Jiuzao (a protein-rich baijiu distillation by-product). This study aimed to explore the interactions between JG and selected FCTs, including resveratrol (RES), quercetin (QUE), curcumin (CUR), and azelaic acid (AZA), and the consequential impact on stability and antioxidant activity of the complexes. The findings conclusively demonstrated that the interactions between JG and the FCTs significantly enhanced the storage stability of the complexes. Moreover, the antioxidant activity of the complexes exhibited improvement compared to their individual counterparts. This study underscores the notion that JG and FCTs mutually reinforce, exerting positive effects on stability and antioxidant activity. This symbiotic relationship can be strategically employed to augment the quality of proteins and enhance the functional properties of bioactive components through these interactions.

Advances in sustainable food packaging applications of chitosan/polyvinyl alcohol blend films

Researchers are addressing environmental concerns related to petroleum-based plastic packaging by exploring biopolymers from natural sources, chemical synthesis, and microbial fermentation. Despite the potential of individual biopolymers, they often exhibit limitations like low water resistance and poor mechanical properties. Blending polymers emerges as a promising strategy to overcome these challenges, creating films with enhanced performance. This review focuses on recent advancements in chitosan/polyvinyl alcohol (PVA) blend food packaging films. It covers molecular structure, properties, strategies for performance improvement, and applications in food preservation. The blend's excellent compatibility and intermolecular interactions make it a promising candidate for biodegradable films. Future research should explore large-scale thermoplastic technologies and investigate the incorporation of additives like natural extracts and nanoparticles to enhance film properties. Chitosan/PVA blend films offer a sustainable alternative to petroleum-based plastic packaging, with potential applications in practical food preservation.

Characterization of chitosan film incorporated pine bark extract and application in carp slices packaging

Active films based on chitosan incorporated with pine bark extract (PBE) were prepared and characterized. Subsequently, these films were utilized for packaging carp slices in refrigerated storage at 4 ± 1 °C. Analysis of the physicochemical properties and biological activity of the active films revealed that, except for water content, all assessed indices showed an increasing trend with an increase in the amount of supplemental PBE. As this trend progresses, scanning electron microscopy (SEM) analysis revealed deposition on the film surface accompanied by transverse lines and fractures, while the color of the film gradually changed from light yellow to reddish-brown. Fourier transform infrared spectroscopy (FTIR) indicated that the phenolic hydroxyl groups in PBE interacted with the hydrogen in the amino groups of chitosan molecules to form non-covalent bonds. X-ray diffraction analysis (XRD) showed that the reaction between PBE and chitosan altered the crystalline structure of chitosan molecules. Moreover, the analysis of the effects of active films on the pH, water-holding capacity, thiobarbituric acid values, and the total bacterial counts of carp slices revealed that in terms of preservation, films containing 30 % PBE were the most effective, using which the shelf life of carp slices could be extended by 50 %.

Stretchable, antifatigue, and intelligent nanocellulose hydrogel colorimetric film for real-time visual detection of beef freshness

The use of biopolymers as matrices and anthocyanins as pH-sensing indicators has generated increasing interest in freshness detection. Nevertheless, the weak mechanical properties and color stability of biopolymer-based smart packaging systems restrict their practicality. In this study, a nanocellulose hydrogel colorimetric film with enhanced stretchability, antifatigue properties, and color stability was prepared using soy hull nanocellulose (SHNC), polyvinyl alcohol (PVA), sodium alginate (SA), and anthocyanin (Anth) as raw materials. This hydrogel colorimetric film was used to detect beef freshness. The structure and properties (e.g., mechanical, thermal stability and hydrophobicity) of these hydrogel colorimetric films were characterized using different techniques. Fourier-transform infrared spectroscopy revealed the presence of hydrogen and ester bonds in the hydrogel colorimetric films, whereas scanning electron microscopy revealed the fish scale-like and honeycomb network structure of the hydrogel colorimetric films. Mechanical testing demonstrated that the SHNC/PVA/SA/Anth-2 hydrogel colorimetric film exhibited excellent tensile properties (elongation = 261 %), viscoelasticity (storage modulus of 11.25 kPa), and mechanical strength (tensile strength = 154 kPa), and the hydrogel colorimetric film exhibited excellent mechanical properties after repeated tensile tests. Moreover, the hydrogel colorimetric film had high transparency, excellent anti-UV linearity, thermal stability and hydrophobicity, and had displayed visually discernible color response to pH buffer solution and volatile NH3 by naked eyes, which was highly correlated with the TVB-N and pH values. Notably, the release of anthocyanin in distilled water decreased from 81.23 % to 19.87 %. The designed SHNC/PVA/SA/Anth hydrogel colorimetric films exhibited potential application as smart packaging film or gas-sensing labels in monitoring the freshness of meat products.

Polyvinyl alcohol/kappa-carrageenan-based package film with simultaneous incorporation of ferric ion and polyphenols from Capsicum annuum leaves for fruit shelf-life extension

Bio-based food packaging materials have elicited growing interests due to their great degradability, high safety and active biofunctions. In this work, by simultaneously introducing the polyphenolic extracts from Capsicum annuum leaves and ferric ion (Fe3+) into the Polyvinyl alcohol/kappa-carrageenan (PVA/κ-carrageenan)-based film-forming matrix, an active package film was developed, with the purpose to improve the food shelf life. The experimental results indicated that the existence of Fe3+ can not only improve the mechanical properties owing to the multiple dynamic coordinated interactions, but also endow the composite films with excellent fire-retardancy. Moreover, the composite films could display excellent UV resistant performance, water vapor/oxygen gas barrier properties and antioxidant activities with the corporation of polyphenols. In particular, the highest DPPH and ABTS radical scavenging capacities for composite film (PC-PLP7 sample) were evaluated to be 82.5 % and 91.1 %, respectively. Higher polyphenol concentration is favorable to the bio-functions of the materials. Benefitting from these features, this novel kind of films with a dense and steady micro-structure could be further applicated in fruit preservations, where the ripening bananas were ensured with the high storage quality. This integration as a prospective food packaging material provides an economic and eco-friendly approach to excavate the high added-values of biomass.

Sustainable strategies for using natural extracts in smart food packaging

The growing demand for sustainable and eco-friendly food packaging has prompted research on innovative solutions to environmental and consumer health issues. To enhance the properties of smart packaging, the incorporation of bioactive compounds derived from various natural sources has attracted considerable interest because of their functional properties, including antioxidant and antimicrobial effects. However, extracting these compounds from natural sources poses challenges because of their complex chemical structures and low concentrations. Traditional extraction methods are often environmentally harmful, expensive and time-consuming. Thus, green extraction techniques have emerged as promising alternatives, offering sustainable and eco-friendly approaches that minimise the use of hazardous solvents and reduce environmental impact. This review explores cutting-edge research on the green extraction of bioactive compounds and their incorporation into smart packaging systems in the last 10 years. Then, an overview of bioactive compounds, green extraction techniques, integrated techniques, green extraction solvents and their application in smart packaging was provided, and the impact of bioactive compounds incorporated in smart packaging on the shelf lives of food products was explored. Furthermore, it highlights the challenges and opportunities within this field and presents recommendations for future research, aiming to contribute to the advancement of sustainable and efficient smart packaging solutions.

Effect of Chitosan and Hyperbranched Poly-L-Lysine Treatment on Quality of Cucumber (Cucumis sativus L.) during Storage

To enhance the storage time of cucumbers, this research investigated the impact of chitosan (CS) and hyperbranched poly-L-lysine (HBPL) on the quality and nutritional attributes of cucumbers when stored at a temperature of 25 °C. The results demonstrated that sensory evaluation scores for cucumbers treated with a CS-HBPL combination were significantly higher than the control (CK), CS, and HBPL groups. On the 18th day of storage, cucumbers in the CK group exhibited significant decay and softening; however, there was a decrease in hardness observed in the CS-HBPL group and no decay or noticeable sour taste was detected. Furthermore, compared to the CK group, treatment with CS-HBPL effectively delayed cucumber decay and weight loss rate while significantly inhibiting decreases in cucumber hardness and growth of surface microorganisms. Additionally, it substantially reduced losses of soluble protein content as well as vitamin C (Vc), reducing sugars, and total phenolic compounds within cucumbers, which were 4.7 mg/g, 4.7 mg/g, 0.94 mg/g, and 0.52 mg/kg, respectively. Moreover, compared to the CK group, combined treatment with CS-HBPL significantly inhibited malondialdehyde (MDA) accumulation and reducing relative electrolyte permeability within cucumbers, which were 1.45 μmol·g-1FW and 29.82%. Furthermore, it notably enhanced activities of superoxide dismutase (SOD) and catalase (CAT), while exerting a significant inhibitory effect on polyphenol oxidase (PPO). In summary, the combined CS-HBPL treatment successfully prolonged cucumber shelf life at room temperature, enabling new possibilities for extending cucumber shelf life.

Strong, tough, high-release, and antibacterial nanocellulose hydrogel for refrigerated chicken preservation

Enormous amounts of food resources are annually wasted because of microbial contamination, highlighting the critical role of effective food packaging in preventing such losses. However, traditional food packaging faces several limitations, such as low mechanical strength, poor fatigue resistance, and low water retention. In this study, we aimed to prepare nanocellulose hydrogels with enhanced stretchability, fatigue resistance, high water retention, and antibacterial properties using soy hull nanocellulose (SHNC), polyvinyl alcohol (PVA), sodium alginate (SA), and tannic acid (TA) as raw materials. These hydrogels were applied in food packaging to extend the shelf life of refrigerated chicken. The structure and properties (e.g., mechanical, antibacterial, and barrier properties) of these hydrogels were characterized using different techniques. Fourier-transform infrared spectroscopy revealed the presence of hydrogen and ester bonds in the hydrogels, whereas scanning electron microscopy revealed the three-dimensional network structure of the hydrogels. Mechanical testing demonstrated that the SHNC/PVA/SA/TA-2 hydrogel exhibited excellent tensile properties (elongation = 160 %), viscoelasticity (storage modulus of 1000 Pa), and mechanical strength (compressive strength = 10 kPa; tensile strength = 0.35 MPa). Moreover, under weak acidic and alkaline conditions, the ester bonds of the hydrogel broke down with an increase in pH, improving its swelling and release properties. The SHNC/PVA/SA/TA-2 hydrogel displayed an equilibrium swelling ratio exceeding 300 %, with a release rate of >80 % for the bioactive substance TA. Notably, antibacterial testing showed that the SHNC/PVA/SA/TA-2 hydrogel effectively deactivated Staphylococcus aureus and Escherichia coli, prolonging the shelf life of refrigerated chicken to 10 d. Therefore, the SHNC/PVA/SA/TA hydrogels can be used in food packaging to extend the shelf life of refrigerated meat products. Their cost-effectiveness and simple preparation make them suitable for various applications in the food industry.

Unlocking sustainable solutions: Nanocellulose innovations for enhancing the shelf life of fruits and vegetables - A comprehensive review

Regarding food security and waste reduction, preserving fruits and vegetables is a vital problem. This comprehensive study examines the innovative potential of coatings and packaging made of nanocellulose to extend the shelf life of perishable foods. The distinctive merits of nanocellulose, which is prepared from renewable sources, include exceptional gas barrier performance, moisture retention, and antibacterial activity. As a result of these merits, it is a good option for reducing food spoilage factors such as oxidation, desiccation, and microbiological contamination. Nanocellulose not only enhances food preservation but also complies with industry-wide environmental objectives. This review explores the many facets of nanocellulose technology, from its essential characteristics to its use in the preservation of fruits and vegetables. Furthermore, it deals with vital issues including scalability, cost-effectiveness, and regulatory constraints. While the use of nanocellulose in food preservation offers fascinating potential, it also wants to be cautiously careful to assure affordability, effectiveness, and safety. To fully use the potential of nanocellulose and advance the sustainability plan in the food business, collaboration between scientists, regulatory bodies, and industry stakeholders is important as we stand on the cusp of a revolutionary era in food preservation.

Multicomponent chitosan complex/polyvinyl alcohol blended film with full-band UV-shielding performance and excellent antioxidant property for active food packaging

Utilizing renewable natural resources to construct multifunctional packaging materials is critical to achieving sustainable development in the food packaging industry. In this study, we crafted transparent films with comprehensive UV-shielding and antioxidant properties by blending a multicomponent chitosan complex with polyvinyl alcohol (PVA), subsequently applied to preserve peanut butter. The multicomponent chitosan complex, synthesized from chitosan, ferulic acid (FA), and 5-oxo-3,5-dihydro-2H-thiazolo [3,2-a] pyridine-7-carboxylic acid (TPCA) through direct heating in water, served as the foundation. This chitosan complex was seamlessly blended with PVA, resulting in the creation of a transparent film through the solvent casting method. A meticulous investigation into the chemical structure and physicochemical properties of the blended films was conducted. The FA and TPCA components exhibited robust ultraviolet absorption properties, conferring virtually complete full-band ultraviolet shielding ability to the blend film. Additionally, FA endowed the blended film with significant antioxidant activity. The effectiveness of the chitosan complex/PVA blended film in preserving peanut butter from oxidative spoilage was demonstrated, showcasing its robustness in food preservation. Our research underscores the significance of creating advanced packaging materials from sustainable sources.

Techno-functional properties of active film based on guar gum-propolis and its application for "Nanguo" pears preservation

Guar gum (GG) composite films, incorporating the ethanolic extract of propolis (EEP), were prepared and subjected to a comprehensive investigation of their functional characteristics. The addition of EEP resulted in a discernible enhancement in the opacity, moisture barrier capacity, and elongation at break. Incorporating EEP led to a noteworthy increase in the total phenolic and total flavonoid content of the films, resulting in superior antioxidant capacity upon GG-EEP films. Remarkably, the addition of 5 % EEP yielded noteworthy outcomes, manifesting in a DPPH radical scavenging rate of 47.60 % and the ABTS radical scavenging rate of 94.87 %, as well as FRAP and cupric reducing power of 331.98 mmol FeSO4-7H2O kg-1 and 56.95 μg TE mg-1, respectively. In addition, GG-EEP films demonstrated antifungal effect against Penicillium expansum and Aspergillus niger, along with a sustained antibacterial effect against Escherichia coli and Staphylococcus aureus. GG-EEP films had superior inhibitory ability against Gram-positive bacteria than Gram-negative bacteria. Crucially, GG-EEP composite films played a pivotal role in reducing both lesion diameter and depth, concurrently mitigating weight loss and firmness decline during the storage period of "Nanguo" pears. Therefore, GG-EEP composite films have the considerable potential to serve as advanced and effective active packaging materials for food preservation.

Improved sustained-release properties of ginger essential oil in a Pickering emulsion system incorporated in sodium alginate film and delayed postharvest senescence of mango fruits

The insufficient water vapor barrier and mechanical capacity of sodium alginate (SA) film limited its application in fruit preservation. Herein, cellulose nanocrystals (CNCs) were used to stabilize Pickering emulsion. Then, we prepared SA composite films. Ginger essential oil (GEO) was loaded as antimicrobials and antioxidants. Finally, the application on mangos were investigated. Compared to coarse emulsion, Pickering emulsion and its film-formation-solution showed more stable system and larger droplet size. The emulsion significantly changed the properties of SA film. Specifically, CNCs improved the thermal, tensile, and barrier properties of the film and GEO enhanced the ultraviolet-visible light barrier capacity. Additionally, the SA/CNC film possessed a homogeneous micromorphology which had a sustained-release effect on GEO, thus maintaining high postharvest quality and long-term bioavailability for mangos. In conclusion, the film prepared via Pickering emulsion showed satisfactory properties which had great potential in fruit preservation.

UV- shielding and antioxidant properties of chitosan film impregnated with Acacia catechu modified with calcium carbonate for food packaging

Acacia catechu contains polyphenolic compounds such as catechin and tannins, which exhibit antioxidant and antimicrobial properties that have the potential to be used in food packaging applications. In this study, chitosan-based (CH) antioxidant films were developed with the incorporation of calcium carbonate (CC) and Acacia catechu (CT). The films were fabricated by the solvent-casting method, and the effects of the different concentrations of Acacia catechu were analyzed. The physicomechanical, antioxidant, and UV shielding properties of the films were determined. The addition of Acacia catechu and calcium carbonate has significantly increased the tensile from 2.30 MPa to 4.95 MPa, respectively, for neat CH and CH/CC/CT-4 film. At the same time, there is a reduction in the elongation at break from 26.75 % in neat CH film to 12.11 % in CH/CC/CT-4 film. The CH/CC/CT-4 film has shown the highest ferric-reducing antioxidant power (FRAP) of 0.440 mg Trolox/g dried weight of the film and 2,2 diphenyl picrylhydrazyl (DPPH) radical scavenging activity of 93.05 %. The UV transmittance of CH/CC/CT-4 film was 0.46 %, the lowest compared to the rest of the fabricated films. These active properties depict that CH/CC/CT-4 film has the potential to be utilized for the packaging of light and oxygen-sensitive food products.

"Review of strategic methods for encapsulating essential oils into chitosan nanosystems and their applications"

Essential oils (EOs) are hydrophobic, concentrated extracts of botanical origin containing diverse bioactive molecules that have been used for their biomedical properties. On the other hand, the volatility, toxicity, and hydrophobicity limited their use in their pure form. Therefore, nano-encapsulation of EOs in a biodegradable polymeric platform showed a solution. Chitosan (CS) is a biodegradable polymer that has been intensively used for EOs encapsulation. Various approaches such as homogenization, probe sonication, electrospinning, and 3D printing have been utilized to integrate EOs in CS polymer. Different CS-based platforms were investigated for EOs encapsulation such as nanoparticles (NPs), nanofibers, films, nanoemulsions, 3D printed composites, and hydrogels. Biological applications of encapsulating EOs in CS include antioxidant, antimicrobial, and anticancer functions. This review explores the principles for nanoencapsulation strategies, and the available technologies are also reviewed, in addition to an in-depth overview of the current research and application of nano-encapsulated EOs.

Chitosan/konjac glucomannan bilayer films: Physical, structural, and thermal properties

To overcome the limitations of chitosan (CS) and konjac glucomannan (KGM), the bilayer films of CS and KGM were prepared by layer-by-layer (LBL) casting method, and the effects of different mass ratios (i.e., C5: K0, C4:K1, C3:K2, C1:K1, C2:K3, C1:K4, and C0:K5) on the microstructures and physicochemical properties of bilayer films were examined to evaluate their applicability in food packaging. The results revealed that the bilayer films had uniform microstructures. When compared with pure films, the bilayer films displayed lower swelling degrees and water vapor permeability. However, the tensile tests revealed a reduction in the mechanical properties of the bilayer films, which was nonetheless superior to that of the pure KGM film. In addition, the intermolecular interactions between the CS and KGM layers were observed through FTIR and XRD analyses. Finally, TGA and DSC analyses demonstrated a decrease in the thermal stability of the bilayer films. Our cumulative results verified that CS-KGM bilayer films may be a promising material for use in food packaging and further properties of the bilayer films can be supplemented in the future through layer-by-layer modification and the addition of active ingredients.

A novel film based on a cellulose/sodium alginate/gelatin composite activated with an ethanolic fraction of Boswellia sacra oleo gum resin

Boswellia sacra and its derivatives exhibit notable bioactive properties, which have been the subject of extensive scientific research; however, their potential applications in food packaging remain largely untapped. In the current study, cellulose, sodium alginate, and gelatin composite edible films were fabricated with the addition of different concentrations (0.2% and 0.3%) of the ethanolic fraction of Boswellia sacra oleo gum resin (BSOR). The resultant films were examined for their physical, chemical, mechanical, barrier, optical, and antioxidant properties. Moreover, the films were characterized using Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) to study the impact of incorporating BSOR on the morphological, crystalline, and chemical properties of the films. The addition of BSOR increased the film thickness (0.026-0.08 mm), water vapor permeability (0.210-0.619 (g.mm)/(m2.h.kPa), and the intensity of the yellow color (3.01-7.20) while reducing the values of both tensile strength (6.67-1.03 MPa) and elongation at break (83.50%-48.81%). SEM and FTIR analysis confirmed the interaction between the BSOR and film-forming components. The antioxidant properties of the edible films were significantly increased with the addition of BSOR. The comprehensive findings of the study demonstrated that BSOR possesses the potential to serve as an efficient natural antioxidant agent in the fabrication of edible films.

Preparation and Characterization of Soluble Dietary Fiber Edible Packaging Films Reinforced by Nanocellulose from Navel Orange Peel Pomace

The packaging problem with petroleum-based synthetic polymers prompts the development of edible packaging films. The high value-added reuse of navel orange peel pomace, which is rich in bioactive compounds, merited more considerations. Herein, nanocellulose (ONCC) and soluble dietary fiber (OSDF) from navel orange peel pomace are firstly used to prepare dietary fiber-based edible packaging films using a simple physical blend method, and the impact of ONCC on the film's properties is analyzed. Adopting three methods in a step-by-step approach to find the best formula for edible packaging films. The results show that dietary-fiber-based edible packaging films with 4 wt.% ONCC form a network structure, and their crystallinity, maximum pyrolysis temperature, and melting temperature are improved. What's more, dietary-fiber-based edible packaging films have a wide range of potential uses in edible packaging.