Biopolymer Food Packaging Films Incorporated with Essential Oils

pH-responsive starch-based bilayer film functionalized with alliin loaded MIL-101 (Fe) for active food packaging

Food packaging films containing antimicrobial reagents play a crucial role in preventing bacterial-induced fruit decay. This study proposes a bilayer film consisting of an internal amino-modified starch hydrophilic layer and an external amino-modified polyvinyl alcohol/polylactic acid hydrophobic layer, embedding alliin@MIL-101(Fe) as an antibacterial agent, utilizing the pH reduction of fruit decay sites to achieve pH-responsive release, enhancing antibacterial performance. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analyses confirm successful crosslinking between amino and aldehyde groups, resulting in the formation of imine bonds and a mesh-like structure conducive to adsorption. Under acidic conditions, the cumulative release rate of alliin reached 74 % within 36 h. Compared to a simple mixture, the tensile strength of the alliin@MIL/NST-NPVA/PLA film reached 34.771 MPa, and transmittance in the wavelength range of 200-370 nm decreased to 0. The scavenging rate of DPPH free radicals in the film can reach 83 %. In addition, the water vapor permeability and oxygen permeability of the film are approximately 7.62 × 10-16 [g/ (m2‧24 h‧0.1 mm)] and 6.83 (m2‧24 h‧0.1 MPa), respectively; moisture content and water solubility decreased to 10.99 % and 20.77 %. This composite film extended the shelf life of strawberries from 2 to 7 days, significantly enhancing freshness.

Application of chitosan/Nano-TiO₂/Daisy essential oil composite film for the preservation of Actinidia arguta: Inhibition of spoilage microorganisms and induction of resistance

This study explores the inhibitory effects of a chitosan/nano-TiO₂/Daisy Essential Oil (CSTD) composite film on spoilage microorganisms affecting Actinidia arguta. Owing to its high nutritional value and water content, Actinidia arguta is highly susceptible to microbial spoilage, leading to a significantly shortened shelf life. Traditional chemical preservation methods are ineffective against microbial spoilage and raise concerns about safety and environmental sustainability, highlighting the demand for natural, effective alternatives. Chitosan, a natural polysaccharide, shows promise due to its biocompatibility and biodegradability. However, its mechanical, antimicrobial, and antioxidant properties require enhancement. To address these limitations, this study incorporates nano-TiO₂ and Daisy Essential Oil into chitosan to develop a composite film. Key spoilage microorganisms of Actinidia arguta were isolated and identified, with Rhizopus stolonifera reported for the first time as one of the spoilage organisms. The composite film demonstrated significant inhibitory effects against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Bacillus amyloliquefaciens, Aspergillus niger, Neopestalotiopsis clavispora, Aspergillus piperis, and Rhizopus stolonifera. Resistance induction experiments further revealed that CSTD effectively delayed oxidative stress and enzymatic degradation linked to fruit spoilage, significantly extending the shelf life of Actinidia arguta. These findings provide theoretical support for developing effective preservation techniques for Actinidia arguta.

Fabrication of sustainable and multifunctional gelatin/dialdehyde pectin composite film incorporating lignin-containing nanocellulose stabilized Pickering emulsion for active food packaging

In response to growing concerns over plastic pollution and food safety, this study aims to develop functional and biodegradable packaging materials from food processing by-products. We prepared eco-friendly active packaging films by integrating pomelo peel essential oils (PEOs)-loaded lignin-containing nanocellulose-stabilized Pickering emulsion (PEOs-PE) into a matrix of fish scale gelatin (FSG) and pomelo peel dialdehyde pectin (DAP). The addition of 30 wt% PEOs-PE significantly improved the mechanical performance of the FSG/DAP composite film, evidenced by a 55.61 % increase in tensile strength (TS) and a 4.09-fold increase in elongation at break (EB). Concurrently, it reduced water solubility, water vapor, and oxygen permeability, while improving thermal stability. At a PEOs-PE content of 40 wt%, the antibacterial activities of the FSG/DAP/PEOs-PE film against S. aureus and E. coli reached 96.59 % and 90.18 %, respectively, while the scavenging rates against DPPH and ABTS radicals were 84.11 % and 94.45 %, respectively. Moreover, the composite film exhibited sustained release of PEOs into food simulants, along with biodegradability and biosafety. Additionally, the FSG/DAP/PEOs-PE composite film effectively safeguarded strawberries against microbial contamination, prolonging their shelf-life to 7 days at ambient temperature. This study offers a promising and sustainable strategy for the development of active food packaging materials.

Biobased Food Packaging Systems Functionalized with Essential Oil via Pickering Emulsion: Advantages, Challenges, and Current Applications

The development of innovative active food packaging is a promising strategy to mitigate food loss and waste while enhancing food safety, extending shelf life, and maintaining overall quality. In this review, Pickering emulsions with essential oils are critically evaluated as active additives for sustainable food packaging films, focusing on their antimicrobial and antioxidant properties, stabilization mechanisms, and physicochemical performances. A bibliometric approach was used to contextualize the current research landscape and new trends. Data were collected from the Web of Science and Scopus databases to find studies published between 2020 and 2024. The analysis of 51 articles shows that cinnamon, clove, and oregano are the most used essential oils, while cellulose and chitosan are the predominant polymer matrices. Pickering emulsions as stabilizers in food science represent a step forward in sustainable emulsion technology. The incorporation of essential oils into biobased films via Pickering emulsions can improve the mechanical and barrier properties, antimicrobial and antioxidant activities, and shelf life of foods. This approach offers a natural, environmentally friendly alternative to conventional materials and is in line with the 2030 Agenda goals for sustainability and responsible consumption. Recent advances show that composite particles combining polysaccharides and proteins have higher stability and functionality compared to single particles due to their optimized interactions at the interfaces. Future research should focus on developing scalable, cost-effective production methods and conducting comprehensive environmental testing and regulatory compliance, particularly for nanotechnology-based packaging. These efforts will be crucial to drive the development of safe and effective biobased active food packaging.

Chitosan-Lemongrass Essential Oil on Paperboard for Active Food Packaging Applications

An active film-forming solution of chitosan and lemongrass essential oil was applied as a coating on paperboard, forming an alternative and sustainable packaging material for food applications. The active paper-film systems were characterized by color parameters, thermogravimetric analyses, contact angles, Fourier transform infrared spectroscopy, X-ray diffraction, mechanical properties, and cytotoxicity. The active coated paperboard was homogeneous and yellowish in appearance. The tensile strength (transverse and longitudinal directions) was directly influenced by increasing the number of layers of the chitosan-lemongrass active coating. The oil concentration significantly affected the Taber stiffness (transverse direction). The active coatings with higher concentrations of lemongrass essential oil altered the thermal stability of the coated paperboard. The contact angle values were characteristic of hydrophobic materials. The coated systems presented three characteristic peaks in the X-ray diffraction analysis-2θ = 16.5°, 22.9°, and 29.8°-and an amorphous halo at 18.9°. The cytotoxicity analysis of the active material (1:40:5) indicated potential reductions in the lemongrass essential oil content to maintain cell viability while ensuring insecticidal efficacy, supporting its safe use as food-contact active packaging. In this way, the active packaging system based on a chitosan coating containing lemongrass essential oil on paperboard could be a type of efficient active material packaging which is safe in contact with food and sustainable for the environment.

Polymers Derived from Agro-Industrial Waste in the Development of Bioactive Films in Food

This review explores the potential of biopolymers as sustainable alternatives to conventional plastics in food packaging. Biopolymers derived from plant or animal sources are crucial in extending food shelf life, minimizing degradation, and protecting against oxidative and microbial agents. Their physical and chemical properties, influenced by the raw materials used, determine their suitability for specific applications. Biopolymers have been successfully used in fruits, vegetables, meats, and dairy products, offering antimicrobial and antioxidant benefits. Consequently, they represent a functional and eco-friendly solution for the packaging industry, contributing to sustainability while maintaining product quality.

Active biodegradable bacterial cellulose films with potential to minimize the plastic pollution: Preparation, antibacterial application, and mechanism

Petroleum-based films have triggered a serious global pollution crisis because they are difficult to recycle, degrade, and reuse. Developing alternative sustainable active films represents a powerful strategy to address these issues. Here, a multifunctional biodegradable bacterial cellulose (BC) film incorporated with guanidine-based polymer (PHGH)/gallic acid (GA) was constructed (termed OBC-PHGH/GA). The resulting OBC-PHGH/GA film exhibited a highly interweaved nanofiber network structure with excellent tensile strength and ductility. The OBC-PHGH/GA film showed an excellent antibacterial effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) with inhibition efficiencies of ∼99.99 % compared with the OBC film. Moreover, the as-prepared film showed excellent UV-shielding, antioxidant, and antifungal activities, showing great potential in food packaging. More importantly, the OBC-PHGH/GA film can be degraded into safe and reusable sugars, demonstrating outstanding environmental friendliness and sustainability. This work provides a promising and unique strategy for designing and fabricating green active packaging materials.

Zein/chitosan Janus film incorporated with tannic acid and cinnamon essential oil co-loaded Pickering emulsion for sustained controlled release and pork preservation

The development of active packaging offers a promising approach to reducing food waste. However, challenges remain, particularly in achieving efficient release dynamics of active compounds and balancing the barrier properties. Herein, a Janus structure zein/chitosan film is custom designed by layer-by-layer casting method to achieve sustainable and unidirectional release performance of antimicrobial agent, which comprises an inner loading layer of tannic acid (TA) and cinnamon essential oil (CEO) co-loaded Pickering emulsion incorporated with chitosan and an outer barrier layer of zein. The good interfacial compatibility between the entities of Pickering emulsion/chitosan loading layer and zein barrier layer had be confirmed via physicochemical structure characterization. The lower swelling rate of Pickering emulsion/chitosan film (47.61 %-51.71 %) indicated the sustained and stable release rate of substances from the inner loading layer, while the zein barrier layer restricted the diffusion of active molecules due to the high swelling rate (162.52 %). In addition, the films showed excellent antimicrobial activity (>99 % against key foodborne pathogens) and radical scavenging activity (2.5-fold enhancement). Moreover, the film loading layer showed predominantly controlled by a quasi-Fickian diffusion, and prolonged the shelf life of pork by 6 days under the unidirectional sustained release. Our work presents a promising fabrication strategy of antimicrobial packaging film with sustainable release performance for food preservation.

Improving the antibacterial properties of polyethylene food packaging films with Ajwain essential oil adsorbed on chitosan particles

The aim of this research is to develop a composite antibacterial film for food packaging using low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyethylene-graft-maleic anhydride (PE-g-MA), and incorporating chitosan (CS) particles onto which ajwan essential oil (AEO) is adsorbed. The films were characterized using various techniques, including Fourier-transform infrared spectroscopy (FTIR), Gas chromatography/mass spectroscopy (GC-MS), X-ray diffraction (XRD), tensile testing, oxygen transmission rate (OTR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and antibacterial assays. FTIR results confirmed the presence of CS and/or AEO in the films. Mechanical testing indicated a decrease in tensile strength and an increase in elongation at break with the addition of AEO, while CS reduced elongation. In the sample containing only 7.5% chitosan (PE-7.5-0), the oxygen permeability was reduced to 910 cm2/m2·day·bar due to the presence of CS. However, the inclusion of AEO in the sample (PE-0-10) increased the oxygen permeability to 2200 cm2/m2·day·bar, which is higher than that of the control sample (PE-0-0) with an oxygen permeability of 1680 cm2/m2·day·bar. The antibacterial activity results demonstrated a synergistic inhibitory effect of CS and AEO. Data from GC-MS and inhibition zone (IZ) tests indicated that while chitosan alone does not exhibit significant antibacterial activity due to its incorporation in the bulk of the film, its combination with AEO enhances antibacterial efficacy. This enhancement occurs as the oil is adsorbed and protected from evaporation during the film formation process. Overall, the findings from this research suggest that the composite film PE-7.5-10, which possesses suitable mechanical properties and significant antibacterial activity, could be an effective candidate for food packaging applications.

Peroxyl Radical Trapping Antioxidant Activity of Essential Oils and Their Phenolic Components

Essential oils (EOs) are gaining importance as sustainable food antioxidants, but kinetic data on peroxyl radical trapping are missing. Thirteen EOs from 11 botanical species were studied in the inhibited autoxidation of cumene by oxygen-uptake kinetics. EOs of Juniperus oxycedrus, Syzygium aromaticum, Thymus vulgaris, Thymbra capitata, Betula alba, Pimenta racemosa, and Satureja montana, containing 23-86% phenolic components by gas chromatography/mass spectrometry (GC-MS) analysis, afforded inhibition rate constants kinh in the order of 104 M-1 s-1 at 30 °C similar to reference butylhydroxytoluene (2,6-di-tert-butyl-4-methylphenol) (BHT). They matched or outperformed BHT in the protection of olive oil. The EOs Daucus carota and Cedrus atlantica with <1% phenols and those of Apium graveolens and Tagetes minuta with no phenolics had no chain-breaking activity. Key components carvacrol, thymol, eugenol, dihydroeugenol, umbelliferone, conyferyl alcohol, o-cresol, m-cresol, p-cresol, 4-allylphenol, 2,3-xylenol, 2,4-xylenol, and phenol had kinh in the range of 103-104 M-1 s-1 and, along with EOs containing them, could potentially replace BHT in the protection of food products.

Poly (lactic acid)/ amine grafted mesoporous silica-based composite for food packaging application

The present study focuses on the development of environmentally friendly bio-composite films using poly(lactic acid) (PLA) as a biopolymer matrix. This is achieved by incorporating amine functionalized green mesoporous silica (GMS) and employing a solution casting method for film fabrication. The motivation behind the work is to improve the compatibility between PLA and green mesoporous silica sourced from rice husk by functionalizing GMS with APTES (3-Aminopropyltriethoxy silane). The primary objective is to explore how the inclusion of GMS influences both the physicochemical attributes and the efficacy of active food packaging in PLA. The introduction of GMS to the PLA matrix not only improves the flexibility of PLA/GMS composite films but also enhances their overall performance. The reinforcement of GMS in the PLA matrix has also significantly contributed towards the reduction in oxygen transmittance rate and provided an anti-bacterial effect towards pathogen i.e. S. aureus and E. coli. The PLA/GMS composite films exhibit antioxidant activity acting as potential scavengers with around 78 % efficacy against DPPH (2,2-diphenyl-1-picrylhydrazyl). Consequently, the PLA/GMS composite formulation proposed in this study shows promising outcomes in terms of strength, flexibility, antioxidant properties, and antibacterial characteristics. Also, the PLA/GMS films extended the shelf life of cut apple samples for seven days.

Pectin-based cinnamon essential oil Pickering emulsion film with two-sided differential wettability: A major role in the spatial distribution of microdroplets

Pickering emulsions have attracted much attention as a novel emulsifying technology. This research to explore Zein-Citrus pectin nanoparticles stabilized cinnamon essential oil (CEO) Pickering emulsion (ZCCPEs) for constructing Pickering emulsion edible film (PEF). Unlike traditional research, which focuses on antibacterial and antioxidant activities, our research examined the physical properties of PEF, specifically changes in wettability. The results show that PEF has better transparency and tensile strength than the pectin alone direct emulsion film (PAEF), and the spatial distribution of Pickering emulsion droplets gives different wettability on both sides of PEF. The partially hydrophobic upside has important application value in food packaging. At the same time, the PEF is biodegradable and environmentally non-polluting. The edible film loaded with essential oils, developed based on the Pickering stabilization mechanism in this study, possesses several desirable characteristics for potential used as bioactive packaging films in food applications.

Integrated supercritical fluid extraction of essential oils

Supercritical fluid extraction (SFE) stands out as an incredibly efficient, environmentally conscious, and fast method for obtaining essential oils (EOs) from plants. These EOs are abundant in aromatic compounds that play a crucial role in various industries such as food, fragrances, cosmetics, perfumery, pharmaceuticals, and healthcare. While there is a wealth of existing literature on using supercritical fluids for extracting plant essential oils, there's still much to explore in terms of combining different techniques to enhance the SFE process. This comprehensive review presents a sophisticated framework that merges SFE with EO extraction methods. This inclusive categorization encompasses a range of methods, including the integration of pressurized liquid processes, ultrasound assistance, steam distillation integration, microfluidic techniques, enzyme integration, adsorbent facilitation, supercritical antisolvent treatments, molecular distillation, microwave assistance, milling process and mechanical pressing integration. Throughout this in-depth exploration, we not only elucidate these combined techniques but also engage in a thoughtful discussion about the challenges they entail and the array of opportunities they offer within the realm of SFE for EOs. By dissecting these complexities, our objective is to tackle the current challenges associated with enhancing SFE for commercial purposes. This endeavor will not only streamline the production of premium-grade essential oils with improved safety measures but also pave the way for novel applications in various fields.

Alginate composite films incorporated with Zn-based inorganic antimicrobials for food packaging: Effects of morphology

Biopolymers-based food packaging materials have drawn attention as potential candidates for substitution of petroleum-based materials. In this study, composite alginate films were developed by incorporating Zn-based antimicrobials to overcome the intrinsic disadvantages of alginates that hinder their wide applications. Antimicrobials with different morphologies (nanoplatelets, nanorods, and nanospheres) were employed to investigate the effects of antimicrobials' morphology on antibacterial, thermal, mechanical, and barrier performance of composite alginate films. Meanwhile, morphological and structural characterizations were carried out to explore the interactions between antimicrobials and alginate matrix. Results indicated that films with nanospheres exhibited superior antibacterial property, while those with one-dimensional nanorods possessed better mechanical and barrier performance. Besides, preliminary test on fresh-cut potatoes and chicken breasts indicated that the composite films showed potential in extending shelf life of foods. By incorporating antimicrobials with three different morphologies, this study provides particular insights into improving properties of composite packaging materials.

A comprehensive review on starch-based sustainable edible films loaded with bioactive components for food packaging

Biopolymers like starch, a renewable and widely available resource, are increasingly being used to fabricate the films for eco-friendly packaging solutions. Starch-based edible films offer significant advantages for food packaging, including biodegradability and the ability to extend shelf life. However, they also present challenges such as moisture sensitivity and limited barrier properties compared to synthetic materials. These limitations can be mitigated by incorporating bioactive components, such as antimicrobial agents or antioxidants, which enhance the film's resistance to moisture and improve its barrier properties, making it a more viable option for food packaging. This review explores the emerging field of starch-based sustainable edible films enhanced with bioactive components for food packaging applications. It delves into fabrication techniques, structural properties, and functional attributes, highlighting the potential of these innovative films to reduce environmental impact and preserve food quality. Key topics discussed include sustainability issues, processing methods, performance characteristics, and potential applications in the food industry. The review provides a comprehensive overview of current research and developments in starch-based edible films, presenting them as promising alternatives to conventional food packaging that can help reduce plastic waste and environmental impact.

One-step spraying of protein-anchored chitosan oligosaccharide antimicrobial coating for food preservation

The persistent global issues of unsafe food and food waste continue to exist. Microbial contamination stands out as a major cause of losses in perishable foods like vegetables and fruits. Herein, we report a self-assembling coating based on disulfide bond cleavage-induced bovine serum albumin (BSA), where the antimicrobial activity of chitosan oligosaccharide (COS) is stably anchored in the coating by electrostatic interactions during the unfolding-aggregation phase of BSA. The intrinsic antimicrobial activity of COS, combined with the positively charged and hydrophobic regions enriched on the BSA coating, significantly disrupts the integrity of bacterial structures. Furthermore, the BSA@COS coating can easily adhere in situ to the grooves on the surface of strawberries through a simple one-step spraying process, extending the shelf life of strawberries and bananas by nearly three times. This makes it a potential economic alternative to current commercial antimicrobial coatings, offering a solution to the rampant global issue of food waste.

Effects of bacterial cellulose/thyme essential oil emulsion coating on the shelf life of chilled chicken meat

BACKGROUND

Bacterial cellulose (BC) is a fiber substance produced by microbial fermentation. It is widely used in the food preservation industry because of its extremely pure texture, high crystallinity and high biocompatibility. In the present study, bacterial cellulose/thyme essential oil (BC/TEO-E) with antibacterial and fresh-keeping functions was prepared by ultrasonic treatment of modified bacterial cellulose for encapsulation of thyme essential oil, which effectively inhibited the spoilage of chilled chicken.

RESULTS

The purified BC, produced by Acetobacter xylinum ATCC 53524, was ultrasonically treated wih different times (0, 30, 60 and 90 min). Transmission electron microscopy, scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and zeta potential were used to characterize the structure of BC after ultrasound, showing that BC, treated for 30 min, had the optimal fiber structure, crystallinity (85.8%), thermal stability (347.77 °C) and solution stability (-26.63 ± 1.96 mV). BC/TEO-E was prepared by a homogenizer for the preservation of chilled chicken. Optical microscopy indicated that the BC/TEO-E prepared by 0.5% BC had optimal dispersion and stability, and even no delamination was observed in the emulsion. Compared with other groups (control, 0.5% BC and Tween-E), the total number of colonies and coliforms in chilled chicken treated with 0.5% BC/TEO-E was the lowest during the whole storage period (12 days), indicating that it can effectively inhibit bacterial growth. In addition, total volatile base nitrogen (TVB-N), thiobarbituric acid reactive substances, pH and drip loss results showed that 0.5% BC/TEO-E could effectively inhibit the spoilage of chilled chicken compared to the other treatment groups.

CONCLUSION

All of the results acquired in the present study indicate that BC/TEO-E has a potential application in chilled chicken preservation. © 2024 Society of Chemical Industry.

Preparation of edible antibacterial films based on corn starch /carbon nanodots for bioactive food packaging

Packaging plays an important role in protecting food from environmental impacts. However, traditional petroleum-based packaging has difficulty in meeting the antimicrobial and antioxidant requirements of prepared foods. This study introduced carbon dots (CDs), prepared by using carrot as a precursor, into corn starch (CS) to construct a bio-friendly composite film with high freshness retention properties. The scavenging of DPPH radicals reached 92.77 % at a CDs concentration of 512 µg/mL, and the antimicrobial activity of CS/5% CDs against Escherichia coli and Staphylococcus aureus was increased to 99.9 %. Notably, the homogeneous doping of CDs creates a dense surface and high carbon content inside the film, which promotes the elasticity and thermal stability of the composite film. Finally, we encapsulated deep-fried meatballs in CS-CDs films. The results showed that the CS-CDs films effectively protected the quality of deep-fried meatballs, and have excellent potential for application in food preservation.

Green synthesis of Poria cocos polysaccharides-silver nanoparticles and their applications in food packaging

To reduce pollution caused by traditional plastic packaging and preparation of silver nanoparticles (AgNPs), this work aims to develop biological macromolecular packaging films with green synthesized AgNPs. In this study, a novel P. cocos polysaccharide (PCP) with a unique monosaccharide composition was extracted from Poria cocos (Schw.) Wolf. Then, this polysaccharide containing 24.68 % rhamnose was used as a stabilizer for the green synthesis of PCP-AgNPs for the first time. PCP-AgNPs exhibited excellent antibacterial activity against P. aeruginosa, E. coli, and S. aureus, with the highest antibacterial activity against E. coli (inhibition zone diameter = 11.14 ± 0.79 mm). Subsequently, PCP-AgNPs/chitosan (CS) film was successfully prepared by incorporating PCP-AgNPs into the CS film solution. Several experiments demonstrated that the addition of this nanomaterial promoted the formation of noncovalent interactions between CS and PCP-AgNPs, resulting in a more regular and denser film. Compared to the CS film and control group, the PCP-AgNPs/CS film significantly maintained the quality indexes of strawberries. Therefore, this composite film successfully extended the shelf life of strawberries. Regarding safety, these packaging films were not cytotoxic toward RAW264.7 cells. In conclusion, the environmentally friendly PCP-AgNPs/CS film has the potential to replace some traditional food packaging materials.

Development of smart colorimetric indicators for tracking kimchi freshness by loading aronia extract in agar, κ-carrageenan, and cellulose nanofiber films

Color indicator films incorporating aronia extract powder (AEP) and biopolymers like agar, carrageenan, and cellulose nanofiber (CNF) were developed to monitor kimchi freshness. AEP-containing films showed strong UV-barrier properties, and reduced light transmittance by 99.12 % for agar, 98.86 % for carrageenan, and 98.67 % for CNF-based films. All AEP-films exhibited high sensitivity to pH changes and vapor exposure to ammonia and acetic acid. Color change notably influenced by the polymer type, particularly evident with ammonia vapor exposure, especially in the AEP/carrageenan film. The chemical structure and thermal stability of the biopolymers remained unchanged after AEP-addition. Tensile strength increased by 24.2 % for AEP/CNF but decreased by 19.4 % for AEP/agar and 24.3 % for AEP/carrageenan films. AEP-containing films displayed strong antioxidant activity, with 99 % free radical scavenging in ABTS and ~ 80 % in DPPH assays. Alkalized AEP-indicator films were more effective in detecting color changes during kimchi packaging tests. Among the labels, alkalized AEP/agar film showed the most obvious color change from green-gray (fresh kimchi, pH 5.5, acidity 0.48 %) to pale brown (optimal fermentation, pH 4.6, acidity 0.70 %), and pale violet-brown (over-fermented, pH 3.80, acidity 1.35 %). Alkalized AEP-indicator films offer promising real-time detection of packed fermented foods like kimchi.

Efficient Fresh Lamp Light-Harvesting Films with the Self-Activating Continuous and Recyclable Bactericidal Ability for Ultrapersistent Freshness of Perishable Muscle Food

A large quantity of perishable muscle food is being wasted due to harmful bacteria infestation during the sales and circulation each year and facing challenges. In this study, a self-activated bactericidal active film (PLA/g-C3N4@PCN-224) responsive to fresh lamp light was prepared, which showed excellent hydrophobicity, water vapor resistance, and thermal stability. Due to the synergistic effect between light-induced reactive oxygen species and the high specific surface area of g-C3N4@PCN-224, this film still maintains 99.99% bactericidal efficacy against Escherichia coli and Staphylococcus aureus after 10 days of continuous bactericidal activity test. The results of cell and hemolysis experiments indicated that the film was safe and nontoxic and can effectively preserve fresh pork for 7 days. Moreover, the film also exhibited a recyclable and efficient killing activity. A strategy for achieving ultrapersistent freshness of perishable muscle food was provided.

Thermal-Driven Curcumin Release Film with Dual-Mode Synergistic Antibacterial Behavior for Efficient Tangerine Preservation

Antimicrobial packing showed great potential in extending the shelf life of food. However, developing a new biocomposite film with an intelligent and efficient antimicrobial performance is still desirable. Herein, a Fe-MoOx encapsulated with curcumin (Cur) filled chitosan-based composite film (CCF films) was prepared by solvent casting method. The total color differences of the CCF films were less than 30%, and satisfactory surface color, transparency, hydrophobicity, and thermal stability were also obtained. Besides, the UV-light/water/oxygen barrier capability and mechanical properties were enhanced with the incorporation of Cur@Fe-MoOx. Moreover, CCF films showed photothermal performance and thermal-controlled curcumin release ability, which endowed the CCF0.15 film with excellent antibacterial capability toward E. coli (≥99.95%) and S. aureus (≥99.96%) due to the synergistic antibacterial effect. Fe-MoOx exhibited high cell viability and less than 5% hemolysis even under the concentration of 500 μg mL-1. Based on those unique characteristics, the CCF0.15 film was chosen for tangerine preservation. The CCF0.15 film could prolong the shelf life of tangerine by at least 9 days compared with the unpacking group, and the tangerines could maintain the freshness characteristics over a 24 day storage period. Such thermal-mediated antibacterial film proposed by our work showed promising potential in food packaging.

Enhancing Gas Transmission Rate of PBS/PBAT Composite Films: A Study on Microperforated Film Solutions for Mango Storage

This study focused on improving the mechanical properties of the poly(butylene succinate) (PBS) film by incorporation of poly(butyrate adipate terephthalate) (PBAT). At 20 wt % PBAT, elongation in the transverse direction improved by 373% while maintaining high tensile strength (27 MPa) and Young's modulus (262 MPa). The PBS80/PBAT20 composite film exhibited optimized mechanical properties. The absorbance coefficient of microperforated film at 980/cm for the 80PBS/20PBAT mix, corresponding to the 10.2 μm CO2 laser wavelength, was 65/cm, indicating high film capability to absorb energy from the CO2 laser. The introduction of microholes enhanced the gas permeability of the PBS/PBAT film. As fluences increased from 187 to 370 J/cm2, there was a notable increase in microhole area in 80PBS/20PBAT film from 19,375 to 46,421 μm2. Concurrently, the gas transmission rate for a singular hole increased from 45 to 210 cm3/d for the oxygen transmission rate (OTR) and from 115 to 220 cm3/d for the CO2 transmission rate (CO2TR). For mango packed in microperforated 80PBS/20PBAT films, the O2 levels inside the package gradually dropped and remained at 14.2% in PBS80/PBAT20-MP1 (OTR ∼ 68,900 cm3/m2·d) and 16.7% in PBS80/PBAT20-MP2 (OTR ∼ 131,900 cm3/m2·d), while CO2 content increased to 6% for PBS80/PBAT20-MP1 and 4% for PBS80/PBAT20-MP2 throughout 33 days. On day 2 of storage in the nonperforated package, O2 content dropped to 2% while CO2 content rose to 22%. Mango packed in the 80PBS/20PBAT film package exhibited an unsatisfactory freshness quality due to the detection of a fermentative odor on day 5 of the storage period. Total soluble solids, color, and weight loss of mango remained stable during storage in all microperforated films. Results demonstrated that the mango shelf life was significantly extended by 35 days using 80PBS/20PBAT-MP1. Laser perforation offered a practical method for improving gas transmission rates (OTR and CO2TR) of 80PBS/20PBAT film for mango packaging.

Nanoscale Pickering emulsion food preservative films/coatings: Compositions, preparations, influencing factors, and applications

Pickering emulsion (PE) technology effectively addresses the issues of poor compatibility and low retention of hydrophobic active ingredients in food packaging. Nonetheless, it is important to recognize that each stage of the preparation process for PE films/coatings (PEFCs) can significantly influence their functional properties. With the fundamental considerations of environmental friendliness and human safety, this review extensively explores the potential of raw materials for PEFC and introduces the preparation methods of nanoparticles, emulsification technology, and film-forming techniques. The critical factors that impact the performance of PEFC during the preparation process are analyzed to enhance food preservation effectiveness. Moreover, the latest advancements in PE packaging across diverse food applications are summarized, along with prospects for innovative food packaging materials. Finally, the preservation mechanism and application safety have been systematically elucidated. The study revealed that the PEFCs provide structural flexibility, where designable nanoparticles offer unique functional properties for intelligent control over active ingredient release. The selection of the dispersed and continuous phases, along with component proportions, can be customized for specific food characteristics and storage conditions. By employing suitable preparation and emulsification techniques, the stability of the emulsion can be improved, thereby enhancing the effectiveness of the films/coatings in preserving food. Including additional substances broadens the functionality of degradable materials. The PE packaging technology provides a safe and innovative solution for extending the shelf life and enhancing the quality of food products by protecting and releasing active components.

Animal derived biopolymers for food packaging applications: A review

It is essential to use environment-friendly, non-toxic, biodegradable and sustainable materials for various applications. Biopolymers are derived from renewable sources like plants, microorganisms, and agricultural wastes. Unlike conventional polymers, biopolymer has a lower carbon footprint and contributes less to greenhouse gas emission. All biopolymers are biodegradable, meaning natural processes can break them down into harmless products such as water and biomass. This property is of utmost importance for various sustainable applications. This review discusses different classifications of biopolymers based on origin, including plant-based, animal-based and micro-organism-based biopolymers. The review also discusses the desirable properties that are required in materials for their use as packaging material. It also discusses the different processes used in modifying the biopolymer to improve its properties. Finally, this review shows the recent developments taking place in using specifically animal origin-based biopolymer and its use in packaging material. It was observed that animal-origin-based biopolymers, although they possess unique properties however, are less explored than plant-origin biopolymers. The animal-origin-based biopolymers covered in this review are chitosan, gelatin, collagen, keratin, casein, whey, hyaluronic acid and silk fibroin. This review will help in renewing research interest in animal-origin biopolymers. In summary, biopolymer offers a sustainable and environment-friendly alternative to conventional polymers. Their versatility, biocompatibility will help create a more sustainable future.

Synthesis, optimization via response surface methodology, and structural properties of carboxymethylcellulose/curcumin/graphene oxide biocomposite films/coatings for the shelf-life extension of shrimp

In this study, carboxymethylcellulose (CMC), curcumin (Cur), and graphene oxide (GO) were used to prepare a novel biocomposite film (CMC-Cur-GO). A central composite design under response surface methodology was employed to optimize the films in terms of water vapor permeability (WVP) and swelling percentage (SP). Under the optimum conditions, which the rates of CMC, GO and curcumin were found to be 1350 mg, 29.99 mg, and 0.302 g, respectively, WVP and SP of CMC-Cur-GO were obtained 0.902 × 10-8 (g/m·h·Pa) and 13.62 %, respectively. The biocomposite films (CMC, CMC-Cur, CMC-GO and CMC-Cur-GO) were characterized by Fourier transform infrared spectroscopy, field-emission scanning electron microscope, thermal gravimetric analysis, X-ray diffraction analysis, ultraviolet-vis light transmittance, moisture content, and mechanical properties. Compared with pure CMC film, the tensile strength, elongation at break and Young's modulus of CMC-Cur-GO were significantly improved by up to 75 %, 41 % and 23 %, respectively (p < 0.05). Then, CMC-Cur-GO was applied as a coating solution for the shrimps. The coated shrimps with the CMC-Cur-GO significantly (p < 0.05) showed a noteworthy improvement in microbial quality (total and psychrotrophic bacterial count), chemical deterioration and lipid oxidation (pH and total volatile basic nitrogen, peroxide value and thiobarbituric acid) and physical characteristic (weight loss) as compared to other samples. The CMC-Cur-GO coating could increase the shelf life of shrimp under refrigerated storage.

A green versatile packaging based on alginate and anthocyanin via incorporating bacterial cellulose nanocrystal-stabilized camellia oil Pickering emulsions

This study aims to develop a versatile intelligent packaging based on alginate (Alg) and anthocyanin (Ant) by incorporating bacterial cellulose nanocrystal-stabilized camellia oil Pickering emulsions. Firstly, bacterial cellulose nanocrystals (BCNs) matrix produced from kombucha was incorporated with camellia oil into via ultrasonic triggering, forming a stable and multifunctional camellia oil-bacterial cellulose nanocrystal Pickering nanoemulsions (CBPE). The microstructure and rheology results of the emulsion confirmed the stabilized preparation of CBPE. Subsequently, the CBPE was integrated into the three-dimensional network structure composed of alginate/anthocyanin. The composite film (Alg-Ant-CBPE) was designed through Ca2+ crosslinking, intermolecular hydrogen bonding and dehydration condensation. The fabricated color indicator films with different concentrations of CBPE (0.1 %-0.4 %), showed varying degree of improvement in hydrophobicity, UV shielding, mechanical strength, thermal stability, water vapor barrier properties and antioxidant capacities. When applied to yogurt, the Alg-Ant-CBPE4 exhibited more pronounced color changes compared to Alg-Ant, enabling visual detection of food freshness. In conclusion, the incorporation of Pickering nanoemulsion provides an effective and promising approach to enhance the performance of polysaccharide-based intelligent packaging.

Synergistic Antimicrobial Hybrid Bio-Surface Formed by Self-Assembled BSA Nanoarchitectures with Chitosan Oligosaccharide

Innovation in green, convenient, and sustainable antimicrobial packaging materials for food is an inevitable trend to address global food waste challenges caused by microbial contamination. In this study, we developed a biogenic, hydrophobic, and antimicrobial protein network coating for food packaging. Experimental results show that disulfide bond breakage can induce the self-assembly of bovine albumin (BSA) into protein networks driven by hydrophobic interactions, and chitosan oligosaccharide (COS) with antimicrobial activity can be stably bound in this network by electrostatic interactions. The inherent antimicrobial activity of COS and the numerous hydrophobic regions on the surface of the BSA-network give the BSA@COS-network significant in vitro antimicrobial ability. More importantly, the BSA@COS-network coating can prolong the onset of spoilage of strawberries in various packaging materials by nearly 3-fold in storage. This study shows how surface functionalization via protein self-assembly is integrated with the biological functioning of natural antibacterial activity for advanced food packaging applications.

Multi-functional konjac glucomannan/chitosan bilayer films reinforced with oregano essential oil loaded β-cyclodextrin and anthocyanins for cheese preservation

In this work, a multifunctional bilayer film was prepared by solvent casting method. Elderberry anthocyanins (EA) were incorporated into konjac glucomannan (KGM) film as the inner indicator layer (KEA). β-cyclodextrin (β-CD) loaded with oregano essential oil (OEO) inclusion complexes (β-CD@OEO) was prepared and incorporated into chitosan (CS) film as the outer hydrophobic and antibacterial layer (CS-β-CD@OEO). The impacts of β-CD@OEO on the morphological, mechanical, thermal, water vapor permeability and water resistance properties, pH sensitivity, antioxidant, and antibacterial activities of bilayer films were thoroughly evaluated. The incorporation of β-CD@OEO into bilayer films can significantly improve the mechanical properties (tensile strength (TS): 65.71 MPa and elongation at break (EB): 16.81 %), thermal stability, and water resistance (Water contact angle (WCA): 88.15°, water vapor permeability (WVP): 3.53 g mm/m² day kPa). In addition, the KEA/CS-β-CD@OEO bilayer films showed color variations in acid-base environments, which could be used as pH-responsive indicators. The KEA/CS-β-CD@OEO bilayer films also presented controlled release of OEO, good antioxidant, and antimicrobial activity, which exhibited good potential for the preservation of cheese. To sum up, KEA/CS-β-CD@OEO bilayer films have potential applications in the field of food packaging industry.

Electrochemistry Study of Bio-Based Composite Biopolymer Electrolyte-Starch/Cardol

The environmental problems generated by pollution due to polymers of petrochemical origin have led to the search for eco-friendly alternatives such as the development of biopolymers or bio-based polymers. The aim of this work was to evaluate the electrochemical behavior of a biopolymer composite made from cassava starch and cardol extracted from cashew nut shell liquid. The biopolymers were prepared using the thermochemical method, varying the synthesis pH and the cardol amounts. The biopolymers were synthesized in the form of films and characterized by cyclic voltamperometry and electrochemical impedance spectroscopy. The biopolymers showed a rich electroactivity, with three oxidation-reduction processes evidenced in the voltamperograms. On the other hand, the equivalent circuit corresponding to the impedance behavior of biopolymers integrated the processes of electron transfer resistance, electric double layer, redox reaction process, and resistance of the biopolymeric matrix. The results allowed us to conclude that the cardol content and the synthesis pH were factors that affect the electrochemical behavior of biopolymer composite films. Electrochemical processes in biopolymers were reversible and involved two-electron transfer and were diffusion-controlled processes.