Characterization of active films based on chitosan/polyvinyl alcohol integrated with ginger essential oil-loaded bacterial cellulose and application in sea bass (Lateolabrax japonicas) packaging

Preparation, characterization, and application of chitosan preservation film doped with polyphenol-nanohydroxyapatite

Effective packaging is crucial for maintaining food quality, safety, and nutritional value. Chitosan (CS) films retard food oxidation by blocking oxygen and water vapor but lack sufficient antioxidant properties for long-term storage. To address this issue, this study investigated the properties of composite films prepared using CS and nanohydroxyapatite (nHAP) loaded with polyphenolic compounds (curcumin, epigallocatechin gallate [EGCG], and quercetin), and their impact on semi-dried golden pomfret (Trachinotus ovatus) freshness. The incorporation of nHAP substantially enhanced the mechanical strength, thermal stability, barrier properties, and oil adsorption capacity of the films. Fourier Transform Infrared Spectroscopy (FTIR) revealed that the incorporation of nHAP or polyphenol-nHAP carriers did not form a substantial number of new chemical bonds or intermolecular crosslinks. Instead, the carriers were continuously dispersed within the CS matrix. Electron microscopy further confirmed the good compatibility between the polyphenol-nHAP carrier and CS matrix. Furthermore, the in vitro drug release profile demonstrated that nHAP effectively controlled polyphenol release, minimizing loss. The composite film significantly reduced the total volatile base nitrogen (TVB-N) of semi-dried golden pomfret fish flesh, delayed protein and lipid oxidation, inhibited microbes, and maintained muscle water-holding capacity. In summary, CS-polyphenol-nHAP films offer a novel method for preserving aquatic products.

A konjac glucomannan/ gelatin film integrated with rosemary essential oil and ginger essential oil-loaded bacterial cellulose: Preparation, characterization, and application in sea bass (Lateolabrax maculatus) packaging

In this study, a konjac glucomannan (KGM)/ gelatin (GEL)-based film integrated with ginger essential oil (GEO) and rosemary essence oil (REO)-loaded bacterial cellulose was prepared. The synergistic effects of GEO and REO were evaluated. The physicochemical, mechanical, optical, morphological, antibacterial, antioxidant properties, thermal stability and preservation effects of the composite films were characterized. Results demonstrated that GEO and REO exhibited synergistic antibacterial activity when combined in a 3:1 ratio. FT-IR analysis, scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed good compatibility among the components of the film. Furthermore, the incorporation of EOs enhanced various properties of the active film including mechanical strength, barrier performance, hydrophobicity as well as its antibacterial and antioxidant capabilities while also improving thermal stability. Additionally, the active film containing 0.8 % (w/v) composite essential oils (KGB-0.8) effectively maintained the quality of refrigerated sea bass and extended the shelf-life for another 6 days.

Characterization of γ-CD-MOF-stabilized thymol Pickering emulsion films with enhanced preservation properties for Basa (Pangasius) fish

Maintaining the freshness of perishable foods, especially seafood, is a major challenge due to rapid spoilage. This study developed active packaging films by incorporating thymol-loaded Pickering emulsions stabilized by γ-cyclodextrin metal-organic framework (γ-CD-MOF) into polyvinyl alcohol (PVA). The films were characterized for their physical, mechanical, and barrier properties. FTIR, XRD, and thermal analysis confirmed successful incorporation and good stability. The films exhibited antimicrobial activity against foodborne bacteria. When applied to Basa fish fillets at 4 °C, the films reduced bacterial counts from 9.87 to 6.1 log CFU/g over 18 days and extended shelf life by 6 days. Chemical stability improvements were observed through changes in pH, TBARS, and TVB-N levels. This research offers a promising approach to addressing food spoilage challenges and provides a potential solution for extending the shelf life of highly perishable seafood products through advanced active packaging technology.

Characterizations of two physically modified sodium alginate composite films doped with gallic acid and their preservation of refrigerated sea bass (Lateolabrax maculatus)

In order to reduce the environmental pressure caused by polyethylene packaging, the study developed gallic acid (GA) containing active films by blending and cross-linking, characterized the effect of different GA contents on the two films, and explored the preservation effect of sea bass wrapped in films containing 2 mg/mL GA and refrigerated at 4 °C for 15 days. The characterization results showed that CF (cross-linked film) had better mechanical and barrier properties than BF (blended film). The microstructure showed that CF had a denser structure than BF. The GA-containing membrane showed complete shielding against UV of about 300 nm. Both membranes showed free radical scavenging of up to 80 % DPPH. The shelf-life of fish wrapped with BF and CF was extended by 6 days compared to the control. Thus, gallium-containing BF and CF are used as renewable films for active packaging to protect products from UV, oxygen and microorganism.

Application of tea tree oil nanoemulsion pads in Lateolabrax japonicas fillets

Abstract

To improve the efficiency of biological preservatives, a novel slow-release system was constructed. The oil-in-water (O/W) nanoemulsions were prepared with tea tree essential oil (TTO) and its main components, 1,8-cineole (CN) and terpinen-4-oil (T4O) as core materials, and with tea saponin as surfactant. The preservation properties of the pad containing nanoemulsion slow-release system on Lateolabrax japonicus fillets were measured. The results showed that the nanoemulsion had good stability and can delay the release of essential oil, and the cumulative release percentage of TTO was as high as 81 % at 72 h. The establishment of nanoemulsions slow-release system effectively improved the preservation properties of the pad, and TTO nanoemulsion pad (TTO-NE-P) had the optimal preservation properties due to the synergistic effect of preservative ingredients and the sustained release system of the nanoemulsion. This study can provide technical support for the combined application of biological preservative agent and aquatic product pads.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01812-9.

Chitosan/collagen films loaded with Pleurotus ostreatus polysaccharide-epigallocatechin gallate conjugates with excellent antioxidant and antibacterial activities for pork preservation

The purpose of this study was to develop a multifunctional active food packaging composite films to solve the environmental and health problems of traditional petroleum-based plastic packaging and for food preservation. The chitosan (CS) based-functional films were prepared by blending collagen (Clg), Pleurotus ostreatus polysaccharide-Epigallocatechin gallate conjugates (POP-EGCG) and ε-Polylysine (ε-PL, PL). The mechanical, physical and chemical properties, antioxidant, antibacterial activity and application in pork preservation were studied. The results showed strong intermolecular hydrogen bond interactions among Clg, POP-EGCG, and ε-PL led to denser, more uniform film surfaces and cross-sections, which significantly enhanced the thermal stability, crystallinity, tensile strength (221.73 %), and elongation at break (21.33 %) of the CS/Clg/POP-EGCG/PL film (P < 0.05). The CS/Clg/POP-EGCG/PL films exhibited excellent water resistance, oxygen barrier properties, UV blocking, slow-release capability, and biosafety. They also demonstrated strong antioxidant (DPPH: 93.10 ± 0.51 %; ABTS: 94.13 ± 0.57 %) and antibacterial effects, thus effectively delaying pork lipid oxidation and microbial growth during refrigeration and extending shelf life by 5 days. This study offers a novel active packaging strategy to extend fresh pork shelf life, facilitating practical applications of CS/CO/POP-EGCG/PL films in food packaging.

Incorporation of co-encapsulated extracts of saffron petal and Stachys schtschegleevii into chitosan/basil seed gum/graphene oxide bionanocomposite: Effects on physical, mechanical, antioxidant, and antibacterial properties

The effects of encapsulation order and concentration (25 % & 50 %) of saffron petal (SPE) and Stachys schtschegleevii (SSE) extracts on the properties of bionanocomposites (BNCs) composed of basil seed gum (BSG), chitosan (CH), and graphene oxide (GO) were evaluated. Two encapsulation approaches were employed: in the first, SPE was encapsulated via complex coacervation using CH and gum Arabic, then mixed with SSE, maltodextrin, BSG, and GO (0.1-0.2 %) before spray drying; in the second, the encapsulation order of SPE and SSE was reversed. Encapsulation order and GO concentration significantly increased thickness (by 20 %), water vapor permeability (by 50 %), and solubility (by 45 %). Thermal stability improved by 10 % in bionanocomposites containing 50 % co-encapsulated extracts. Fourier transform infrared spectroscopy confirmed the successful incorporation of co-encapsulated extracts, while microscopic analysis revealed small cracks with micro- and nano-sized particles (219 nm to 8.3 μm) in BNCs with spray-dried coacervates. Co-encapsulation enhanced antibacterial and antioxidant activity, while encapsulation order regulated the sequential release of bioactive compounds, enabling controlled antimicrobial or antioxidant release based on food deterioration patterns. These findings highlight the potential of co-encapsulated extracts in developing advanced BNCs for active food packaging, where controlled release of bioactive compounds is essential for preserving food quality.

The Antimicrobial and Antioxidant Effects of Bilayer Films Based on Polylactic Acid (PLA)/Chitosan: Starch Containing Bitter Orange Essential Oil on the Fresh Rainbow Trout (Onchorhynchus mykiss) Fillet

This study investigated the antibacterial properties of polylactic acid (PLA)/chitosan: starch films incorporated with bitter orange essential oil (BOEO) for preserving rainbow trout fillets. Three BOEO concentrations (0.7%, 1.4%, and 2.1% w/w) were incorporated via casting. Increased BOEO concentration enhanced film hydrophobicity and thermal resistance, but reduced tensile strength while increasing elongation. Atomic force microscopy revealed altered surface roughness. Antibacterial testing showed optimal activity against both Gram-positive and Gram-negative bacteria at 1.2% BOEO. Films containing 1.2% BOEO were applied to rainbow trout fillets, significantly reducing spoilage bacteria (total bacterial count, psychrotrophic, lactic acid bacteria, and Enterobacteriaceae), slowing chemical spoilage (pH and TBA values), and minimizing weight loss during 16 days of refrigerated storage (4°C). These results demonstrate the potential of BOEO-incorporated PLA/chitosan: starch films for extending the shelf life of rainbow trout.

Chitosan-pullulan edible coating loaded with dihydromyricetin: Enhanced antioxidant activity and barrier properties to prolong Cantonese sausages' shelf-life

Cantonese sausages are susceptible to oxidative deterioration during storage. Compared with synthetic antioxidants, dihydromyricetin (DMY) is a natural active substance with various functions such as antioxidant and antimicrobial. In this study, edible coating solutions loaded with DMY were prepared based on chitosan (CS) and pullulan (PUL) to prolong the shelf-life of Cantonese sausages. FT-IR and XRD results showed good compatibility between DMY and CS-PUL. It was found that 8 % DMY was physically cross-linked with CS and PUL mainly through hydrogen bonding, which enhanced the barrier and mechanical properties of the films. Meanwhile, the antioxidant property, antimicrobial efficiency and thermal stability of the films were also significantly improved (p < 0.05). The results of storage experiments of Cantonese sausages showed that the 8 % DMY-CP coating solution could effectively retard the lipid oxidation of Cantonese sausages at 25 °C, and maintain the appearance and flavour of products at storage on the 28th d. This study proved DMY's potential as a natural alternative to synthetic additives in polysaccharide-based edible coatings, providing a green and sustainable solution to combat lipid oxidation in meat products.

New advances in biological preservation technology for aquatic products

Aquatic products, characterized by their high moisture content, abundant nutrients, and neutral pH, create an optimal environment for the rapid proliferation of spoilage organisms, lipid oxidation, and autolytic degradation. These factors collectively expedite the spoilage and deterioration of aquatic products during storage and transportation within the supply chain. To maintain the quality and extend the shelf-life of aquatic products, appropriate preservation methods must be implemented. The growing consumer preference for bio-preservatives, is primarily driven by consumer demands for naturalness and concerns about environmental sustainability. The present review discusses commonly employed bio-preservatives derived from plants, animals, and microorganisms and their utilization in the preservation of aquatic products. Moreover, the preservation mechanisms of bio-preservatives, including antioxidant activity, inhibition of spoilage bacteria and enzyme activity, and the formation of protective films are reviewed. Integration of bio-preservation techniques with other methods, such as nanotechnology, ozone technology, and coating technology that enhance the fresh-keeping effect are discussed. Importantly, the principal issues in the application of bio-preservation technology for aquatic products and their countermeasures are presented. Further studies and the identification of new bio-preservatives that preserve the safety and quality of aquatic products should continue.

An Antibacterial and Antioxidant Food Packaging Film Based on Amphiphilic Polypeptides-Resveratrol-Chitosan

Antimicrobial and antioxidant packaging films play a crucial role in extending food shelf life, maintaining quality, and enhancing safety by inhibiting microbial growth and slowing oxidation processes. However, most commercial preservative films suffer from limited antimicrobial and antioxidant properties. Moreover, these films are made from petroleum-based materials that degrade into microplastics, resulting in environmental contamination and potential health risks for humans. Herein, an antibacterial and antioxidant food packaging film (CS-SAP@R) is developed by integrating star-shaped amphiphilic polypeptides (SAP) and resveratrol (R) into the chitosan (CS) matrix. The incorporation of SAP not only effectively addresses the existing compatibility issues between the highly hydrophobic resveratrol and water-soluble CS film, but also significantly enhances the antimicrobial properties of CS. Additionally, the well-integrated resveratrol molecules endow the film with superior antioxidant properties. Furthermore, CS-SAP@R has achieved bacterial killing rates of 97.31% against E. coli and 99.05% against S. aureus. The enhanced characteristics of the CS-SAP@R film contribute to its exceptional preservation performance, effectively extending the shelf life of perishable products by ≈3 days when stored at 4 °C. These remarkable attributes underscore the benefits of polypeptide-based biopolymers and demonstrate the potential applicability of the CS-SAP@R film in effectively safeguarding perishable products.

Research Progress Regarding Psychrotrophic Pseudomonas in Aquatic Products: Psychrophilic Characteristics, Spoilage Mechanisms, Detection Methods, and Control Strategies

Aquatic products are an important part of the human diet, but they are easily contaminated by Pseudomonas spp., which leads to food deterioration and economic loss. In this paper, the main characteristics of psychrotrophic Pseudomonas in aquatic products are reviewed, including its growth adaptation mechanism and biofilm formation ability at low temperatures, and the key role of psychrotrophic Pseudomonas in aquatic product spoilage is emphasized. Studies have shown that psychrotrophic Pseudomonas can produce a variety of volatile compounds by decomposing proteins and amino acids, affecting the sensory quality and safety of aquatic products. A variety of control strategies to extend the shelf life of aquatic products have been explored, including physical, chemical, and biological methods, particularly biofilm-specific inhibition techniques such as inhibition of quorum sensing and the application of natural antimicrobials. Future research should prioritize the development of novel anti-biofilm products to address the growing problem of psychrotrophic Pseudomonas contamination in the aquatic product industry to ensure food safety and public health.

Preparation of chitosan/polyvinyl alcohol antibacterial indicator composite film loaded with AgNPs and purple sweet potato anthocyanins and its application in strawberry preservation

This study incorporated purple sweet potato anthocyanin (PSPA) and silver-nanoparticles (AgNPs) into the chitosan/polyvinyl alcohol film matrix (PVA/CS) to successfully prepare a composite film, which effectively inhibited bacterial growth and indicated product freshness. The addition of AgNPs and PSPA led to a dense structure of the film, which effectively enhanced its physical properties, barrier properties and functional properties. The incorporation of PSPA made the composite film highly pH-sensitive, which exhibited distinct color changes in varying pH solutions. The PVA/CS-AgNPs-PSPA10 composite film with PSPA and AgNPs resulted the shelf life of strawberries to 13 days at 4 °C, which effectively reduced strawberry breathing during storage. Additionally, such composite film changed color from purple to yellow-purple, indicating the deterioration of strawberries. It also showed an antibacterial indication through its excellent antibacterial property and freshness indication performance, which demonstrated its significance in developing antibacterial indicator composite packaging materials for fruits and vegetables preservation.

Production of Oncorhynchus mykiss biosensor based on polyvinyl alcohol/chitosan nanocomposite using phycocyanin during refrigerated storage

Smart packaging, also known as intelligent packaging, is responsive to external stimuli, moisture, light, oxygen, heat, pH, and bacterial growth. In this study, polyvinyl alcohol/nanochitosan/phycocyanin nanocomposite (PVA/NCH/PC-NC) for fish fillets of Oncorhynchus mykiss rainbow trout coating was prepared. Five treatments were prepared over a period of 14 days (0, 1, 7 and 14 days) under treatments of T1: fish coated with PVA/NCH-NC without PC; T2, T3, T4 and T5 fish coated with PVA/NCH/PC-NC (0.5, 1, 1.5 and 2% PC respectively). Moreover, the results showed that higher concentrations of PC in PVA/NCH polymer matrix resulted in a net-like morphology on the film's surface. Also, after 21 days of storage, the T4 treatment had the lowest levels of mesophilic, psychrophilic, and Enterobacteriaceae bacteria (8.17 ± 0.02, 7.90 ± 0.04, and 60.67 ± 0.02 log cfu/g, respectively). Additionally, it was seen that PVA/NCH/PC-NC improved the Sensory evaluation of fish fillet samples during 14 days of storage (p < 0.05). Overall, the results showed that the prepared PVA/NCH/PC-NC (2% PC) film function as an intelligent packaging solution in food preservation and freshness monitoring applications of Oncorhynchus mykiss fillet in terms of mechanical, microbial and sensorial evaluation.

Design and Characterization of Polyvinyl Alcohol/Kappa-Carrageenan Pickering Emulsion Biocomposite Films for Potential Wound Care Applications

This study aimed to develop polyvinyl alcohol (PVA) and kappa-carrageenan (κCA) biocomposite films using a Pickering emulsion technique for wound care applications. Juniper essential oil and modified sepiolite were incorporated to enhance functionality, with films prepared via solvent casting and characterized for structural, thermal, and mechanical properties. The PCOS-2 film exhibited the highest mechanical performance, with Young's modulus of 6.25 ± 1.3 MPa, tensile strength of 5.65 ± 1.7 MPa, and elongation at break of 608.96% ± 72.8%. Antibacterial assays showed inhibition zones of 9 and 10 mm against Staphylococcus aureus and Escherichia coli, respectively, for the PCOS-2 film, while antioxidant activity reached 63% DPPH radical scavenging after 12 h. Additionally, porosity and hydrophilicity were enhanced, as indicated by contact angles of 55° for the control film and 71.2° for PCOS-2. These results underscore the potential of PVA/κCA biocomposite films as sustainable and bioactive wound dressings, combining mechanical resilience, bioactivity, and environmental compatibility, with future efforts focused on optimizing antibacterial efficacy against gram-negative bacteria and clinical validation.

Fabrication of antimicrobial packaging based on polyaminopropyl biguanide incorporated pectin/polyvinyl alcohol films for fruit preservation

Pectin (PEC)/polyvinyl alcohol (PVA), plasticizers, and polyaminopropyl biguanide (Pb) (0.125%-1%) were used to prepare the film solution. The results demonstrated significantly enhanced tensile strength and elongation at break of PEC/PVA/Pb 0.25% film than PEC/PVA film. Scanning electron microscopy was carried out to investigate the continuous and dense structure of the PEC/PVA/ Pb0.25% film. FTIR, XPS, and XRD revealed that Pb addition to the PEC/PVA film matrix changed its physicochemical properties by forming new hydrogen and CN bonds. Moreover, the composite films exhibited strong antimicrobial activity against food-borne microorganisms (E. coli and S. aureus), and post-harvest pathogens (P. italicum and F. proliferatum) in vitro. The composite film effectively inhibited P. italicum growth during citrus experiments, while maintaining nutritional components (vitamin C, total flavonoid, and total polyphenol content). Overall, the antimicrobial composite film presented promising applicability in food packaging.

Polyvinyl alcohol/soybean isolate protein composite pad with enhanced antioxidant and antimicrobial properties induced by novel ternary nanoparticles for fresh pork preservation

In this study, oregano essential oil (OEO)-loaded soluble soybean polysaccharide (SSPS) -nisin nanoparticles (ONSNPs) were formulated through electrostatic attraction-driven and hydrophobic interactions utilizing SSPS, nisin, and OEO as raw materials. ONSNPs were integrated into polyvinyl alcohol (PVA) and soybean protein isolate (SPI) matrices to create composite pads (PS-ONSNPs) by physically cross-linked using a simple freeze-thaw cycling process. The effects of ONSNPs content on the structure and physicochemical properties were evaluated. The results revealed that strong intermolecular interactions between ONSNPs and the PS matrices affected the crystallinity, microstructure, and thermal stability of the pads. Upon incorporating 5 % to 15 % ONSNPs, the structure of composite pads became denser, and the mechanical properties and water resistance were enhanced. Concurrently, the PS-ONSNPs pads facilitated the protection and controlled release of OEO. Furthermore, ONSNPs significantly improved the antioxidant activity of the pads and effectively inhibited the growth of Staphylococcus aureus and Escherichia coli. The prepared PS-ONSNPs 15 % pad was applied to storage experiments of fresh pork, which could extend the shelf life of meat to 10-12 days under 4 °C storage conditions. Therefore, the composite pad devised in this research holds promise as a viable option for intelligent active packaging of fresh meat.

PBAT/PLA food packaging film containing sodium dehydroacetate-loaded diatomite as an antibacterial agent: Fabrication, water-gas regulation and long-acting antimicrobial mechanism

Biodegradable food packaging films with good antimicrobial properties are highly sought after for prolonging the shelf-life of fruits and vegetables whilst minimizing waste streams originating from the food sector. In this work, a series of PBAT/PLA food packaging films containing sodium dehydroacetate-loaded diatomite (SD/D) as an antimicrobial agent were fabricated. Structural analyses showed that the sodium dehydroacetate was incorporated into the pores of the diatomite. A uniform dispersion of SD/D in the composite films effectively enhanced water and gas permeability, whilst also giving the films good mechanical properties. The slow release of SD endowed the composite films with long-acting antibacterial ability (>90 % bacteriostasis rate for E. coli and >85 % bacteriostasis rate for S. aureus). The composite films were able to effectively maintain the quality of banana fruits during storage at room temperature, encouraging their use in food applications where non-biodegradable petrochemical-derived packaging films have traditionally been used.