ABSTRACT The low hydrophobicity and antibacterial activity of carboxymethyl cellulose (CMC) film limit its application in food packaging. This study added casein nanoparticles loaded with Litsea cubeba essential oil and polylactic acid to CMC, and assembled a composite CMC film (LC/C‐P) by forming an emulsion system. The tensile strength, elongation at break, hydrophobicity and antibacterial activity of LC/C‐P films are significantly higher than those of CMC films. The incorporation of PLA into the CMC matrix increased the essential oil loading capacity and facilitated more controlled release compared with the CMC film without PLA. Meanwhile, compared with the layered assembled CMC polylactic acid bilayer film (LC/C‐PL), the LC/C‐P film formed by the emulsion system has better mechanical properties and hydrophobicity, and the preparation method is simpler. The application experiment results show that LC/C‐P film can significantly inhibit the growth of various foodborne pathogenic bacteria in fresh meat, and effectively extend its shelf life to 7 days, with excellent potential for food packaging applications.
ABSTRACT Essential oils are promising active agents for food packaging, but their volatility and limited thermal tolerance hinder incorporation into melt‐processed films. Herein, oregano essential oil (OEO)/β‐cyclodextrin (β‐CD) inclusion complexes (CD‐O) were fabricated to improve the handling and thermal retention of OEO during melt processing. The synthesized CD‐O was blended with poly(butylene adipate‐co‐terephthalate) (PBAT) via extrusion blow moulding to prepare biodegradable active packaging films. The resultant CD‐O achieved 61.0% encapsulation efficiency and an inhibition‐zone diameter of 22.60 ± 1.31 mm against Penicillium digitatum . Its dispersion at 10.0 mg/mL exhibited a DPPH radical scavenging rate of 75.6%. The release behaviour of OEO from CD‐O in n ‐hexane followed the Higuchi model ( R 2 = 0.9961), consistent with sustained release under the tested conditions. Thermogravimetric characterization validated that the initial volatilization temperature of OEO in CD‐O increased to 150°C, representing greatly enhanced thermal stability. CD‐O mitigated the loss of tensile strength and the increase in water vapour permeability associated with β‐CD addition. At 15% CD‐O loading, oxygen transmission rate was not significantly different from that of neat PBAT. For P. digitatum ‐inoculated Bingtang oranges, CD‐O/PBAT composite film delayed the onset of disease symptoms by 2 days. For fresh oranges, the composite film suppressed fruit respiration intensity and weight loss and maintained high levels of ascorbic acid and total phenols throughout storage. This work supports the feasibility of melt‐processed CD‐O/PBAT films for active citrus packaging, which possess great potential for fruit preservation.
Postharvest spoilage of fruits and vegetables is accompanied by high humidity and acidification in the microenvironment, whereas conventional packaging materials fail to respond to these complex environmental signals. Herein, an innovative synergistic covalent-noncovalent locking strategy was proposed to fabricate a pH- and humidity-dual-responsive biodegradable composite film. Unlike conventional single-responsive controlled-release systems, citral (CIT) was immobilized in the film matrix in two forms: via covalent anchoring through dynamic imine bonds and via noncovalent encapsulation by hydroxypropyl-beta-cyclodextrin (HP beta CD). This structure enables the coordinated on-demand release of active ingredients, rather than relying on passive diffusion. The release results of the film indicated that under pH 7 and 43% RH, the cumulative release percentage of CIT was controlled below 7.88% +/- 0.19%. In contrast, significant CIT release was observed in an acidic and high-humidity environment (pH 4, 98% RH) that simulated actual fruit rotting. The pH-triggered cleavage of imine bonds and humidity-induced network swelling jointly endow the film with environment-adaptive release performance, offering a new design strategy for intelligent recognition of complex biological microenvironments. Practical preservation tests demonstrated that the optimized CCPH15 film extended the shelf life of cherry tomatoes by 4-10 days. The film presented high antibacterial efficacy, with inhibition rates of 99.97% against E. coli and S. aureus. Moreover, the material attained a soil degradation rate of 42.37% +/- 1.76% within 10 days. This study provides a novel theoretical basis and technical route for next-generation smart packaging capable of precise targeted intervention in postharvest food preservation.
Starch/poly(butylene adipate-co-terephthalate) (PBAT) composite films containing dual silicate fillers were fabricated by extrusion blowing for biodegradable modified-atmosphere packaging (MAP). The combination of diatomite, kaolin and zeolite was associated with a filler-mediated interfacial network that enhanced mechanical strength, flexibility and transparency while regulating gas-transport pathways. A steady-state analysis suggested that the internal CO2/O2 equilibrium depends on the coupling between fruit respiration and film gas selectivity. Among all formulations, the diatomite-zeolite film (D-Z) exhibited balanced O2/CO2 permeability, low humidity sensitivity and superior structural uniformity, enabling the formation of a stable atmosphere with low O2 (1.1%) and moderate CO2 (14.3%) levels. When applied to cherry preservation, the D-Z film effectively delayed spoilage and maintained fruit quality. This work provides a feasible strategy for designing sustainable, humidity-tolerant and atmosphere-regulating bioplastic films for fresh produce packaging.
ABSTRACT In this study, 2‐hydroxy‐5‐octanoylbenzoic acid (HOBA) was successfully intercalated into Zn–Al layered double hydroxide (LDH) via ion‐exchange to form HOBA‐LDH with simultaneously enhanced thermal stability, enhanced UV absorption, hydrophobicity, antioxidant activity, and antimicrobial performance. HOBA‐LDH exhibited remarkable antibacterial activity against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) with both inhibition rates exceeding 99.9%. Multifunctional composite films were fabricated by melt‐casting HOBA‐LDH with polyethylene (PE). Compared with pure PE, the composite films showed enhanced tensile strength, higher elongation at break, reduced oxygen and water vapour transmission rates, superior UV‐barrier properties, and effective antimicrobial activity against E. coli and S. aureus with inhibition rates of 94.0% and 78.9%, respectively. Application tests demonstrated that composite films effectively preserved Red Globe grapes, reducing weight loss, suppressing respiration intensity, preventing microbial spoilage, while maintaining fruit firmness, sweetness and prolonging sensory quality for up to 30 days. The results clearly show that HOBA‐intercalated LDH fillers enhance the overall performance of the composite films. Composite films exhibit strengthened mechanical properties, reduced water and oxygen permeability, and improved antibacterial activity. In conclusion, these improvements indicate the strong promise of active food packaging materials.
