The development of sustainable active packaging materials is essential to reduce reliance on petroleum-based plastics while improving food preservation. Herein, we report the development of multifunctional biocomposite films based on poly(butylene adipate-co-terephthalate) (PBAT) by partially substituting it with acetylated thermoplastic starch (A-TPS) and incorporating tannic acid (TA) through a scalable twin-screw extrusion process for packaging applications. A-TPS incorporation provided a renewable starch-based component that enhanced the sustainability of the packaging material and decreased PBAT usage. Structural and morphological analyses indicated improved interfacial compatibility between PBAT, A-TPS, and TA, resulting in a compact polymer network. Consequently, PBAT/A-TPS–TA films exhibited improved tensile strength, enhanced UV-shielding capability, substantially reduced oxygen permeability, and concentration-dependent changes in water vapor permeability. The films showed notable antioxidant activity, demonstrated by enhanced DPPH and ABTS radical scavenging abilities, along with antibacterial effects against E. coli and S. aureus. Moreover, pork loin packaging tests at 4 °C showed that the PBAT/A-TPS–TA 1.0% film inhibited microbial growth and lipid oxidation while better maintaining color and pH during 12 days of storage. This study offers a novel active packaging approach designed to enhance quality and shelf life while facilitating cost-effective and sustainable materials for food packaging applications.
Because fruits and vegetables are highly perishable, their postharvest preservation remains a persistent challenge. Biopolymer-based packaging films are promising sustainable preservation materials, but their functional properties require enhancement through specific modification strategies. This review comprehensively discusses how physical, enzymatic, and chemical cross-linking regulate biopolymer network structures and thereby improve film functional properties. The preservation performance of different biopolymer-based cross-linking films for postharvest preservation of fruits and vegetables is also summarized. Cross-linking forms covalent bonds and ionic bridges, and strengthens noncovalent interactions, thereby altering functional-group availability and reorganizing biopolymer networks. These changes generally restrict polymer-chain mobility and produce denser and more continuous film structures, thereby improving mechanical properties, barrier performance, water resistance, and the sustained release of active ingredients. In particular, pH-responsive dissociation of reversible imine bonds and metal-phenol coordination can trigger release of active ingredients. Moreover, excessive cross-linking may impair film performance. Through improved water and gas regulation, mechanical integrity, and sustained release of active ingredients, cross-linking films can effectively reduce water loss and softening, regulate respiration and ripening, alleviate oxidative damage, and suppress microbial spoilage in fruits and vegetables. Notably, recent studies have increasingly focused on the development of milder and safer cross-linking strategies, together with the integration of multiple functionalities. Overall, cross-linking-induced network reorganization is central to the regulation of film functional properties and preservation performance. By elucidating the relationships among cross-linked network structure, functional properties, and preservation performance, this review provides new insights and theoretical guidance for the rational design of high-performance biopolymer-based films for fruit and vegetable preservation.
Active fruit packaging must retain functional compounds during mild storage yet release them when the package microenvironment becomes warm and humid. Here, we developed a feedback-gated gelatin/carboxymethyl cellulose hydrogel liner (CCE@Cu) by incorporating copper-coordinated epigallocatechin-3-gallate (EGCG)–arginine adducts (EA) into a covalently crosslinked protein–polysaccharide network. In this design, reversible humidity- and temperature-induced network relaxation serves as the gate controlling swelling and active-component release. Spectroscopic, chromatographic, and high-resolution mass-spectrometric analyses supported EA formation, including an ion at m/z 631.1877 ([M−H]⁻) consistent with a 1:1 EGCG–arginine species. Increasing relative humidity from 40 to 60–95% enlarged the mean pore diameter from 1.39 ± 0.58–16.39 ± 5.72 μm, while heating enhanced swelling and the release of EA and trace total copper. CCE@Cu recovered 87.43 ± 9.71%–94.38 ± 0.24% of its storage modulus after repeated 1%/500% step-strain cycles and dissipated 41.98 ± 0.23%–49.76 ± 6.44% of the loading energy over 50 compression cycles. The liner also showed sustained 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity and predominantly bacteriostatic effects, reducing viable Escherichia coli by 0.63 log and Staphylococcus aureus by > 3.21 log under the tested conditions. In closed-package storage, CCE@Cu reduced banana weight loss and browning over 24 d and delayed strawberry weight loss, softening, and decay over 12 d, retaining strawberry firmness at 469.60 ± 54.31 kPa and limiting decay to approximately 3%. These findings establish CCE@Cu as a microenvironment-responsive active liner that integrates gated delivery, mechanical cushioning, and fruit-quality preservation.
The transition toward sustainable active packaging demands eco-friendly and non-toxic biomaterials with high functional performance. Natural biopolymer-based films are often limited by the inherent hydrophilicity and insufficient functional activity of their constituent materials, while the tendency of plant proteins to aggregate may further compromise the structural and functional properties of protein-polysaccharide films. A bioactive sodium alginate (SA)-based composite film was fabricated by incorporating modified rice residue protein (RRP) (MP1: single pH-shifted RRP, MP2: ultrasound-assisted pH-shifted RRP), and its application potential in the postharvest preservation of blueberries was further evaluated. The optimized SA/MP2 film exhibited excellent surface hydrophobicity with a water contact angle of 102.10° (pure SA: 69.6°), 8.9% reduced water vapor permeability, augmented thermal stability, and enhanced mechanical properties, as well as improved UV–vis barrier characteristics. Additionally, the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging capacity of the SA/MP2 film was determined to be 32.89% compared with 20.13% observed for the neat SA film. Afterward, the SA/MP2–5% film effectively extended the shelf life of blueberries by reducing the weight loss and decay rate, while maintaining fruit hardness and soluble solids content. The microflora analysis revealed that beneficial epiphytic yeast genera within the blueberry fungal community under MP2 intervention were predominantly Kondoa (16%), Symmetrospora (8%), and Aureobasidium (2%). These findings indicated that the developed multifunctional active film has great application potential for sustainable food packaging, and provides a promising strategy for high-value utilization of agricultural waste.
A highly effective UV-blocking ZnO nanocomposite (NC) coating was developed to enhance the shelf life of polyunsaturated fatty acid-rich oils. Three variants of ZnO nanoparticles (NPs), ZnO-A, ZnO-X, and ZnO-Y, were synthesized via a greener sonochemical route using zinc acetylacetonate hydrate [Zn(acac)2⋅H2O] and varying NaOH concentrations. A mixture (1:1:1 ratio by weight) of these ZnO NPs was utilized to exploit the UV and blue-light blocking capabilities of each variant. The mixed ZnO NPs were incorporated into methylcellulose (MC) biopolymer solution (1.0, 3.0, and 5.0 wt% of MC) and coated onto glass vials using a dip coater. The MC/5.0 wt% ZnO NC coating achieved ∼98.67% UVA and ∼99.08% UVB blocking, comparable to amber glass. Groundnut and flaxseed oils were stored in coated, uncoated, or amber glass vials and exposed to sunlight or kept in a photostability chamber as per ICH Q1B guidelines. After 16 days of sunlight exposure, MC/5.0 wt% ZnO NC-coated glass vials exhibited peroxide values (PVs) of ∼4.91 meq O2 kg−1 (groundnut oil) and ∼10.26 meq O2 kg−1 (flaxseed oil) compared to ∼18.09 meq O2 kg−1 and ∼76.15 meq O2 kg−1, respectively, for oils stored in uncoated glass. In the photostability chamber, PVs were ∼2.66 meq O2 kg−1 (groundnut oil) and ∼7.96 meq O2 kg−1 (flaxseed oil) for MC/5.0 wt% ZnO NC-coated glass vials upon exposure to 1.2 million lux hours and 200 Wh m−2, compared to ∼10.39 meq O2 kg−1 and ∼17.83 meq O2 kg−1, respectively, for those stored in uncoated glass. A lower carotenoid loss was observed for both oils stored in MC/5.0 wt% ZnO NC-coated vials compared to oils stored in uncoated glass vials, demonstrating the coating’s potential to improve their shelf life without compromising visual appeal.
Paper-based food contact materials (FCMs) are increasingly adopted as plastic alternatives, yet concerns persist regarding per- and polyfluoroalkyl substances (PFAS) intentionally or incidentally present in coatings and additives. Here, a high-resolution mass spectrometry (HRMS)-based non-targeted strategy was applied to characterize PFAS in paper-based FCMs. This workflow comprised two key steps: (1) prioritizing candidate PFAS features using suspect screening and Kendrick mass defect (KMD) filtering, and (2) compound identification with reference standards, spectral database matching, and in silico prediction. In total, 28 PFAS were identified in FCM extracts, including six not previously reported in paper-based FCMs, expanding the chemical space of interest for packaging safety. Targeted quantification and semi-quantification revealed wide, product-specific concentration ranges dominated by short-chain PFAS and selected fluorotelomer species, with sporadic occurrences of long-chain PFAS. To translate material burdens into consumer relevance, the migration test with aqueous and fatty food simulants (10% and 50% ethanol, v/v) was performed. Twelve of the 28 PFAS exhibited measurable migration in at least one simulant. Estimated daily intakes (EDI) were calculated using consumption factors and food-type distribution factors (adult scenario: 100 g/day; 70-kg body weight). The results indicate that hazard quotients were below 1, suggesting limited risk under the tested scenarios. This integrated pipeline provides actionable evidence for packaging selection, safer material substitution, and surveillance of emerging PFAS in paper-based FCMs.
While Ethyl Lauroyl Arginate (LAE) has traditionally been incorporated into polymers intended for antimicrobial packaging, its application onto polymers remains limited and its incorporation into/application onto polymers using large-scale manufacturing procedures is even more scarce. This study aimed to develop a combined plasma-induced surface activation and salt-assisted stabilization method to create an antimicrobial coating made of LAE for polyethylene terephthalate (PET) and likely other polymers. After determining the minimum inhibitory and bactericidal concentrations of LAE for Escherichia coli and Listeria innocua, active PET sheets with LAE were produced by first evaluating plasma parameters able to increase surface energy (pressure, air flow, and time) and then various aqueous salts as a top layer for the LAE coated on the plasma-treated PET. The active sheets were characterized for coating chemical structure, morphology, adhesion, LAE release, and validated for antimicrobial activity. The results showed that the LAE coating was attached to plasma-treated PET with a high cohesive force (a breaking strength σ > 234.4 kPa) when disodium phosphate (DSP) in aqueous solution was layered on top of the LAE coating. As demonstrated by the changes in the FTIR absorption bars, this is due to a combination of hydrogen bounding, ionic bounding, and van der Waals forces between DSP, LAE and PET. The coating reduced 5–8 logs of E. coli and L. innocua, and fully detached from the PET in aqueous food simulants (∼20–40 ppm of LAE). Our research shows promising results for the scalable development of antimicrobial LAE-coated PET sheets, which could reduce food deterioration, thereby promoting increased food safety.
The excessive use of non-biodegradable plastic food packaging has led to severe environmental pollution, highlighting the urgent need for eco-friendly materials that are biodegradable, environmentally sustainable, and effective in food preservation. This work discusses the feasibility of preparing multifunctional paper packaging materials coated by poly(vinyl alcohol) (PVA) and natural thymol (THY), a poor water solubility naturally derived phenolic compound with antimicrobial activity. An emulsion was prepared using octenyl succinic anhydride (OSA) as the solvent for THY, xanthan gum as the emulsifier, and this emulsion was applied as a functional additive into PVA coating. OSA also served as a crosslinking agent for PVA, enhancing the coating density and improving the barrier properties of the coated paper. The results demonstrated that OSA did not reduce the antibacterial efficacy of THY, confirming the compatibility between OSA and THY. When the emulsion concentration was 3.0%, the water vapor permeability of the coated paper decreased from 4.75 × 10⁻¹ ³ to 3.02 × 10⁻¹ ³ kg·m/(m²·s·Pa) compared with PVA coated paper, and its oil resistance Kit rating reached 12. The THY/OSA/PVA coated paper extended the shelf life of strawberries to 8 days without visible spoilage. This work provides a promising strategy for the fabrication of multifunctional packaging material, offering a convenient method to integrate water insoluble solid functional components into bio-based degradable materials without traditional organic solvents. It advances the technology of environmentally friendly food packaging, provides insights for the development of active packaging and biodegradable materials, and lays a foundation for the future optimization and industrialization of such materials.
Traditional homogeneous films are often unable to simultaneously maintain a high-humidity microenvironment and buffer relative humidity (RH) fluctuations during fresh-produce storage. Herein, a zein-based asymmetric active packaging film was developed by integrating a ligand-regulated Zein@Metal Azolate Framework 47 (Zein@MAF47) humidity-buffering layer with a dense Zein/humic acid (Zein/HA) barrier layer. MAF47 was grown in situ on electrospun zein fibers through a layer-by-layer assembly strategy, and the 2-methylimidazole/3-methyl-1H-1,2,4-triazole (Hmim/Hmtz) ligand ratio was tuned to regulate water adsorption–desorption behavior. Among the investigated samples, Zein@MAF47 with an Hmim/Hmtz ratio of 3:1 exhibited high-humidity-responsive S-shaped sorption behavior, a water uptake of 0.42 g/g at 90% RH, and stable cycling performance. Meanwhile, the Zein/HA layer formed a compact hydrocolloid network through electrostatic interactions and hydrogen bonding, resulting in a low water vapor permeability of (1.89 ± 0.06) × 10−11 g·m/(m2·s·Pa). The resulting Zein@MAF47 −Zein/HA bilayer film showed directional water vapor transport and rapidly stabilized the RH at (80 −82)% in a model humidity-regulation system. In preservation experiments, this packaging maintained the internal RH above 97%, thereby reducing the weight loss of Agaricus bisporus to 8.96% under refrigerated conditions and 4.10% at room temperature. These results indicate that coupling a humidity-responsive porous layer with a compact moisture-barrier layer is a promising strategy for developing active packaging films for humidity-stabilized fresh-produce preservation.
This study integrated molecular networking (MN) with non-targeted analytical method for rapidly identification of unknown migrants from disposable aluminum food container coatings as prepared dishes package under high-temperature conditions. MN clustered and annotated migrants based on spectral similarity and common fragments, while reducing data redundancy and false-positive assignments. Using this workflow, 31 migrants were rapidly characterized classified into two groups: bisphenol A diglycidyl ether (BADGE)-based epoxy resin oligomers and p-tert-butylphenolic resin oligomers. As some unknown migrants were derivatives of oligomers, their identification was refined using feature fragment observed in the MS/MS spectra. Structural elucidation was further confirmed by collision cross-section (CCS) values, which exhibited consistent trend lines within the same type of oligomers and their derivatives. Quantitative analysis indicated that high temperature promotes the migration of substances and the generation of derivatives. A preliminary risk assessment based on the threshold of toxicological concern (TTC) revealed that the estimated exposure levels of 15 compounds exceeded their corresponding TTC thresholds, highlighting an urgent need for further toxicological data and risk assessment focused on these oligomers.
The global transportation of fruits demands packaging systems that integrate preservation functionality, mechanical robustness, and environmental sustainability. In this work, a rigidity-affinity mechanism was proposed to construct starch/poly(butylene adipate-co-terephthalate) (PBAT) composite films. By tailoring the processing routes, tannic acid (TA), serving as an interfacial regulator, was directed to preferentially anchor onto rigid silicate fillers (diatomite and zeolite) through multidentate hydrogen bonding. The resulting TA–silicate assemblies established dynamic non-covalent interactions between starch and PBAT phases, enhancing interfacial compatibility. The obtained blown-extrusion films achieved superior tensile strength (15.93 MPa), Young’s modulus (254.90 MPa), UV-shielding capability, and moisture resistance. Gas permeability selectivity was tunable via processing history, enabling regulation of the CO2/O2 permeability ratio from 1.00 to 8.20. The films effectively extended the shelf life of both climacteric (banana) and non-climacteric (strawberry) fruits. After disposal, the films exhibited favorable environmental compatibility and safety. These findings demonstrate that the processing-mediated rigidity-affinity mechanism provides a scalable pathway for designing mechanically robust, gas-regulating, and environmentally sustainable biodegradable food packaging materials.
Fungal spoilage in packaged foods results in substantial economic losses and poses a threat to global food safety. This study presents, for the first time, the application of marine-derived antifungal additives, laminarin and fucoidan, for the development of active poly(lactic acid) (PLA) composites using conventional melt processing. Natural antifungal additives are typically heat-labile and frequently degrade during the melt processing of polymeric composites. This work introduces a strategy to improve their thermal stability by intercalating laminarin and fucoidan into magnesium aluminium layer double hydroxide (Mg-Al LDH), with their properties compared to those of commercial nystatin. Intercalation of antifungal agents at various concentrations was confirmed by X-ray diffraction (XRD), and thermogravimetric analysis (TGA) demonstrated approximately 50% greater thermal stability for intercalated agents compared to virgin samples. Antifungal assays against three Candida species indicated enhanced activity for both virgin and intercalated samples. PLA composites containing both virgin and best performing intercalated antifungal agents (T10, L6 and F3) were fabricated and characterised using scanning electron microscopy (SEM), TGA, differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), XRD, water contact angle (WCA), water vapour transmission rate (WVTR), mechanical testing, and assessments of antioxidant and antifungal activity. The composites exhibited a threefold reduction in water vapour permeability; however, they displayed decreased tensile strength and thermal stability. Antifungal efficacy, evaluated using disc diffusion and contact-dependent assays, demonstrated that the PLA composites possess antifungal activity through a contact-dependent mechanism.
Chemical migration from food packaging materials poses significant challenges to product safety, shelf-life, and consumer health. Nylon-6:polyethylene multilayer films are widely used for packaging fat-rich products such as ghee in India. This study evaluated packaging safety through efficient extraction of intentionally added substances (IAS) and non-intentionally added substances (NIAS) from 35 retail ghee packaging films using focused ultrasound liquid-solid extraction (FULSE) coupled with GC-MS profiling. A total of 87 extractables including UV stabilisers, antioxidants, hydrocarbons, plasticizer-related compounds, breakdown products, and NIAS, were tentatively identified. Of these, only 19 substances were listed under Commission Regulation (EU) No. 10/2011, as amended by Commission Regulation (EU) No. 2023/1442. Subsequently, a modified unsaponifiable matter-based extraction coupled with low-temperature purification was developed and validated for simultaneous determination of ten selected packaging-derived compounds in 22 commercially packaged ghee samples using gas chromatography–tandem mass spectrometry (GC-MS/MS). The method exhibited excellent recoveries (91.02–105.34%), low relative standard deviation (0.67–9.01%), and negligible matrix interferences. Acetyl tributyl citrate (ATBC) was detected at highest concentrations (0.67–7.28 mg kg−1), followed by Irgafos®168 and 13-docosenamide. Concentrations of all quantified compounds remained below their applicable specific migration limits (SMLs), indicating compliance with their prescribed regulatory thresholds. Nevertheless, comprehensive safety evaluation requires consideration of unidentified NIAS and cumulative dietary exposure. Overall, the developed workflow provides rapid and reliable approach for extractables screening and targeted determination of packaging-derived compounds in commercially packaged ghee, supporting systematic monitoring of contaminants in high-fat dairy products.
Vegetable oils are stored and transported in high-density polyethylene (HDPE) packaging, yet the temperature dependence of triacylglycerol sorption and diffusion into HDPE remains insufficiently quantified. Here, rapeseed oil uptake into HDPE sheets was measured gravimetrically between 30 and 90 °C and interpreted using a one-dimensional plane-sheet diffusion model including finite interfacial mass-transfer resistance. The interfacial mass-transfer coefficient was estimated from a stagnant-fluid correlation. Equilibrium oil uptake was measured at 70 °C and above and extrapolated to lower temperatures, and the apparent diffusion coefficient was obtained by fitting uptake kinetics. Equilibrium oil uptake increased from 0.024 kg·kg−1 at 70 °C to 0.030 kg·kg−1 at 90 °C. The apparent Flory-Huggins interaction parameter decreased from about 2.5 at 30 °C to about 2.0 at 90 °C, indicating limited but increasing affinity of rapeseed oil for the amorphous HDPE phase. The fitted apparent diffusion coefficient increased strongly with temperature, from about 1.9·10−15 m²·s−1 at 30 °C to about 2.0·10−12 m²·s−1 at 90 °C, with an activation energy close to 102 kJ·mol−1. The calculated mass-transfer Biot numbers remained below commonly used thresholds for negligible external resistance, showing that interfacial mass transfer can influence the apparent uptake kinetics at elevated temperature. One-sided simulations of package-wall exposure predicted negligible through-thickness penetration at ambient temperature over shelf-life durations, whereas moderate temperature elevation accelerated oil ingress. These results provide temperature-dependent apparent transport and sorption parameters for rapeseed oil in HDPE and highlight the importance of accounting for solubility, diffusion, and finite interfacial resistance when predicting oil-polymer interactions under storage.
Thermoplastic polyurethane (TPU) hydration packs are widely used for fluid storage in demanding scenarios such as outdoor endurance sports and military operations, where repeated use and prolonged contact with water are common. However, limited information is available on the chemical stability of TPU materials and their behaviour under realistic usage conditions.This study investigates the migration of volatile and non-volatile compounds from commercial and used TPU pouches under conditions simulating real use. Advanced analytical techniques (SPME-GC-MS and UPLC-QTOF) were applied to characterize migrants across different food simulants (10% ethanol, 3% acetic acid, tap water, and mineral water), temperatures (40 and 60 °C), contact times (6 and 24 h), and repeated use cycles.Results revealed a complex migration profile, with 28 non-volatile and nearly 200 volatile compounds identified. The occurrence of compounds such as isophorone, tetrahydrofuran (THF) oligomers, and triphenylphosphine oxide (TPPO) suggests that both material composition and degradation processes contribute to chemical release. Repeated use and elevated temperatures were found to influence migration patterns, indicating changes in material stability over time.These findings provide new insights into the behaviour of TPU-based hydration systems under realistic conditions and highlight the importance of considering repeated-use scenarios when evaluating the suitability of polymeric materials for food and beverage contact applications.
This study investigates how processing conditions, particularly temperature, affect wax adhesion on glass wine bottlenecks and the related long-term barrier properties of the sealing system. First, the surface properties of both glass and liquid wax were characterized at temperatures corresponding to the classical coating process conditions. While the total surface tension of glass (25°C to 70°C) and wax (100°C to 120°C) remained stable, the balance between polar and dispersive components shifted slightly with temperature, with the dispersive component becoming predominant at higher temperatures. Second, extraction force tests and oxygen permeability measurements revealed that the temperature of the bottleneck during wax application critically determines the final barrier performance. When wax was deposited on glass heated between 25°C and 50°C, oxygen transfer was highly heterogeneous, with OTR values ranging from low (<0.1 mg·year⁻¹) to very high (>30 mg·year⁻¹). This also correlated with weaker extraction forces from the wax to the bottleneck, around 50 N. However, applying wax to bottlenecks preheated to temperatures between 60°C and 70°C consistently led to stronger adhesion, evidenced by higher extraction forces and low, homogeneous OTR values (<0.1 mg·year⁻¹), similar to the intrinsic barrier properties of the wax. These results demonstrate that higher bottleneck temperatures (>60°C) during wax application improve adhesion between wax and glass and effectively limit oxygen ingress through the wax–glass interface. Overall, this work identifies bottleneck preheating as a critical processing parameter that governs wax adhesion and, in turn, long-term oxygen protection.
The ageing of cork stoppers is a critical issue for the oenology industry. This study employed a repeated loading method to characterise the evolution of the compressive behaviour of aged cork-based stoppers, addressing the lack of reliable mechanical indicators of ageing. First, natural and agglomerated cork stoppers, as well as polyurethane binder, were subjected to a 200-day ageing period at 50°C either in contact with water (liquid phase) or with ethanol (vapour or liquid phase). In addition to sorption, imbibition and swelling phenomena were observed. After the ageing period, the volume filled by water was estimated at 52% for natural, and of 75% for agglomerated cork. Higher values were estimated for ethanol, with 84% for the cork-based samples and 97% for the polyurethane binder. Second, after vacuum treatment to remove water and ethanol, the aged samples underwent 8 compression cycles at 43% Hencky strain. The tangent modulus was calculated to assess the instantaneous mechanical response, whereas the dissipated energy was calculated to characterise the evolution of the compressive behaviour over cycle repetitions. The results suggest that water and ethanol can interact with the components of a cork-based stopper and thus play a key role in altering their mechanical behaviour during ageing.
