Production and Characterization of Polyvinyl Alcohol-Chitosan-Carrageenan Biocomposite Films Containing St. John's Wort (Hypericum perforatum) Oil

Preparation and application of bio-based degradable films loaded with Litsea Cubeba essential oil microcapsules for the preservation of refrigerated sea bass (Lateolabrax maculatus).

This study developed Litsea cubeba essential oil (LCEO) microcapsules (LWM) incorporated into chitosan/polyvinyl alcohol (CP) films to create active composite packaging (CPM), with their physicochemical properties and preservative effects on refrigerated sea bass systematically evaluated. SEM confirmed that LCEO was effectively encapsulated within whey protein isolate-maltodextrin (WPI-MD) wall materials, forming stable microcapsule structures. Furthermore, incorporating 0.8% LWM significantly enhanced film performance, increasing tensile strength by 101.2% and reducing oxygen transmission rate by 58.4%, while providing superior sustained-release properties with a 35.7% lower LCEO release rate than the control. Moreover, CPM films exhibited strong antioxidant and antibacterial activities, along with excellent biodegradability. Preservation experiments proved that the CPM composite film successfully increased the first-grade freshness by 3 d and the shelf-life by 6 d. Therefore, this work provides a promising approach for developing bio-based active packaging to maintain the quality and extend the shelf-life of perishable seafood.

Development and characterization of bioactive citric acid-crosslinked chitosan films functionalized with sorghum extracts.

While chitosan has emerged as a leading biodegradable alternative to petroleum-based plastics, its high moisture sensitivity and limited active functionality often compromise its barrier performance and shelf-life extension capabilities in food-packaging applications. In this study, citric acid-crosslinked chitosan films plasticized with glycerol and functionalized with sorghum glume extracts were developed and characterized. Film thickness remained uniform (0.046-0.056 mm), indicating good casting reproducibility, with reduced water sensitivity, resulting in moderate water solubility (16.8-19.5%), and low water vapour permeability (0.533-0.605 × 10-9 g·m-1·s-1·Pa-1). Increasing glycerol content enhanced film flexibility, with EAB reaching up to 53.47%. Sorghum extracts improved the functional performance of the films, reducing transparency and increasing UV-light shielding while enhancing antioxidant activity. The highest antioxidant performance was observed in films containing 10% extract. SEM analysis revealed smooth, homogeneous, and defect-free surfaces, whereas FTIR and DSC analyses suggest strong intermolecular interactions leading to improved thermal stability and matrix cohesion. The immobilized 3-deoxyanthocyanidins exhibited pH-dependent color responses across a pH range of 1-12 and maintained their coloration under alkaline conditions, reflecting their inherent stability. However, the gradual color transitions indicate greater suitability for active antioxidant packaging than intelligent pH-indicator applications. Moreover, 10% extract-loaded films represent the most promising candidates due to their superior functional performance. The incorporation of sorghum glume extract transformed chitosan films into active bio-based systems with enhanced antioxidant protection, improved light barrier properties, and maintained physicochemical stability.

Fabrication of chitosan composite films reinforced with fish scale gelatin-hydroxyapatite and syringaldehyde for beef preservation.

Fish scale waste was valorized to develop a biodegradable active film with enhanced preservation performance. Gelatin and hydroxyapatite were extracted and combined with chitosan, while syringaldehyde was incorporated as a natural crosslinker and antibacterial agent to construct a dual-network structure. The combination of HAP reinforcement and SA-induced crosslinking promoted the formation of a denser organic-inorganic network structure, thereby improving the physical performance and functional properties of the films. Compared with the blank GC film, the incorporation of HAP and SA led to the formation of GCHS films with overall enhanced physical performance and functionality. Especially, the optimized GCHS3 film exhibited improved elongation at break (51.7%), UV-blocking ability (blocking >99% of UV passage), DPPH radical scavenging activity (82.3%), and antibacterial effects against Escherichia coli and Staphylococcus aureus (with inhibition zone diameters of 14.09 mm and 24.00 mm, respectively). During cold storage of beef samples, the GCHS3 film efficiently inhibited microbial growth, delayed the accumulation of total volatile basic nitrogen, and retarded pH increase, while maintaining the original color characteristics of beef. Consequently, the shelf life was extended to 9 days, which is superior to PE packaging. This study provides a novel strategy to incorporate fish scale-derived inorganic fillers and natural crosslinkers into protein-polysaccharide systems. The GCHS3 film exhibits great potential as a sustainable alternative for active food packaging, especially for fresh meat preservation.

Enhancing the Mechanical and Barrier Properties of Seaweed-Cassava Starch Bioplastics with Natural Additives for Sustainable Food Packaging

The growing accumulation of petroleum-based plastic waste has intensified the search for biodegradable alternatives from renewable resources. This study investigated the effect of clove essential oil (CEO) on the mechanical and barrier properties of composite bioplastic films from semi-refined carrageenan and cassava starch (30:70) with 30% glycerol. Unlike previous studies using purified biopolymers or focusing solely on antimicrobial effects, this work uniquely evaluates CEO as a dual-function agent plasticizer and hydrophobic barrier enhancer within a low-cost carrageenan–starch matrix to identify the optimal loading for balanced packaging performance. Films were prepared by solution-casting with CEO at 0, 0.5, 1.0, 1.5, and 2.0% (w/w). Increasing CEO content decreased tensile strength (18.2 to 12.1 MPa) and Young's modulus (612 to 365 MPa), while elongation increased (22.4% to 41.6%). WVP and oxygen permeability decreased by 39% and 43%, respectively, alongside an increase in contact angle (68.4° to 89.6°), indicating enhanced hydrophobicity. FTIR confirmed physical dispersion without new covalent bonding. Films remained biodegradable, though higher CEO slowed degradation. The 1.0–1.5% CEO formulation offered the most balanced combination of flexibility, barrier performance, and degradability for sustainable food packaging.

Enhancing the Mechanical, Barrier, and Biodegradability Properties of KGM/Agar/Pullulan Composite Films Through Controlled Deacetylation for Sustainable Packaging

This study investigates the controlled deacetylation of konjac glucomannan (KGM) and its incorporation into agar (AGAR) and pullulan (PUL) to fabricate composite films (DKAP) for sustainable packaging applications. The effects of varying deacetylation degrees on the physicochemical and functional properties of KGM and the resulting films were systematically evaluated. FTIR analysis confirmed effective acetyl removal with an increase in deacetylation degree, which was accompanied by reduced viscosity. Moderate deacetylation improved intermolecular interactions, leading to enhanced mechanical strength, water vapor barrier properties, and hydrophobicity. The D 4 KAP film, with optimal deacetylation, exhibited the best overall performance, with a tensile strength of 85.47 ± 4.21 MPa and a water vapor permeability of 0.98 ± 0.06 × 10 −6  g·m −1 ·h −1 ·Pa −1 . Additionally, the D 4 KAP film showed reduced swelling and solubility compared to other films. Excessive deacetylation (above 35%) caused aggregation, structural defects, and reduced performance. All films remained biodegradable in natural soil, and fruit preservation tests (bananas and strawberries) showed that D 4 KAP effectively reduced water loss and preserved fruit quality, demonstrating its potential as an eco‐friendly packaging material. These results provide new insights into the optimization of biodegradable films for food packaging, highlighting the significance of controlled deacetylation in improving film performance and sustainability.

Smart Multifunctional Biocomposite Films from Tamarind Seed Starch/Cotton Waste Fibre, and Butterfly Pea (Clitoria ternatea) for Sustainable Food Packaging