Physico-chemical and antimicrobial characteristics of novel biodegradable films based on gellan and carboxymethyl cellulose containing rosemary essential oil

Eco-friendly carboxymethyl cellulose films incorporated with phenolic compounds from hydrodistillation wastewater of rosemary essential oil

The food packaging industry seeks innovative materials that enhance food preservation while promoting sustainability. This study investigated the development of carboxymethyl cellulose (CMC) films incorporating both rosemary essential oil (EO) and phenolic compounds extracted from the hydrodistillation wastewater of rosemary. The aqueous extract (AE), rich in rosmarinic acid, caffeic acid, chlorogenic acid, vanillic acid, luteolin, rosmanol, and carnosic acid, was used to improve the bioactive properties of the films. Four formulations were produced: CMC (control), CMC/EO (with essential oil), CMC/AE (with aqueous extract), and CMC/EO/AE (with both EO and AE). The incorporation of EO and AE increased the film thickness and altered microstructural properties, with EO-containing films exhibiting larger voids due to oil droplet coalescence. Films with AE showed a significantly higher yellowing index and superior UV barrier properties, which could protect light-sensitive foods. FTIR and XRD analyses confirmed successful incorporation of bioactive compounds, while solubility tests revealed that EO-containing films were fully soluble, whereas AE-containing films exhibited reduced solubility (∼50 %), enhancing their potential for moisture-sensitive food applications. EO increased film flexibility, whereas AE-containing films demonstrated improved antioxidant activity, with FRAP and TEAC values approximately 300 % and 700 % higher, respectively, compared to the control. These films have potential for food packaging applications, particularly for lipid-rich foods prone to oxidative degradation (e.g., nuts, dairy, processed meats) and fresh produce susceptible to photodegradation. By utilizing a by-product of the essential oil industry, this study contributes to the development of sustainable and functional food packaging solutions.

Preparation, characterization, and antibacterial properties of a soybean protein isolate/gelatin composite film containing rosemary-modified bentonite and application of fresh lemon slices

To address the rapid deterioration of fruit slices, soy protein isolate (SPI) and gelatin (GEL) composite films were optimized for food packaging using rosemary-modified bentonite (RB) as an active ingredient and glycerol as a plasticizer to enhance flexibility. Composite films with RB demonstrated superior ultraviolet-visible (UV-Vis) light barrier properties, increased opacity, and enhanced mechanical performance, achieving a tensile strength of 2.27 MPa. Barrier properties were significantly improved, with reduced water vapor transmission rate (1.85 × 10-3 g·m-2·s-1) and oxygen permeability (6.69 × 10-3 g·m-2·s-1), alongside elevated hydrophobicity, antibacterial activity, and antioxidant capacity (DPPH scavenging activity: 54.74 %; ABTS scavenging activity: 53.89 %). In preservation trials with fresh lemon slices, RB/SPI/GEL-2 films reduced weight loss to 37.89 %, maintained firmness at 0.99 N, stabilized pH at 3.14, and extended freshness lifetime by delaying mold formation. These results confirm that RB/SPI/GEL films effectively preserve freshness and minimize nutritional loss in lemon slices, demonstrating their feasibility for fruit preservation applications.

Effect of coatings containing 1-methylcyclopropane or mandarin peel extract on the freshness and metabolic profiles of cold stored strawberry

The application of coatings is a strategy for maintaining the freshness of highly perishable fruits. This research aimed to evaluate the quality indices of strawberries (Amaou) coated with new coatings based on the sodium carboxymethyl cellulose (CMC) and cellulose nanofibres (CNF) with incorporated mandarin peel extract (ME) or 1-methylcyclopropene (1-MCP) during storage at 20days at 5 °C and 85% relative humidity (RH). Dissolving the coating solution containing ME in 1-MCP maintained its colour for up to 50 days. Coatings enhanced with ME and/or 1-MCP maintained fresh strawberries more effectively than the control, reducing weight loss and maintaining firmness, total soluble solids (TSS), citric acid, colour, and total phenolic content. The CCM2-2 coating solution showed superior effects on the weight loss and relative percentages of strawberry metabolites compared to the other coatings, as confirmed by the different components.

Composite film based on carboxymethyl cellulose and gellan gum with honokiol-β-cyclodextrin inclusion complex: Characterization and application in strawberry preservation

The aim of this study is to fabricate a biodegradable film based on carboxymethyl cellulose and gellan gum (CMC/GG) with the honokiol/β-cyclodextrin inclusion complex (HNK/β-CD). The HNK/β-CD was prepared by freeze-drying and its physicochemical properties were investigated. Then HNK/β-CD was added to CMC/GG solution to form CMC/GG honokiol inclusion complex (HIC) composite film by the casting method. The physicochemical properties, antioxidant and antibacterial effects, and strawberry preservation function were investigated. The composite film with 0.18 % inclusion complex (CMC/GG/0.18 % HIC) was found to be the optimal formulation. The film had a tensile strength of 8.20 MPa and an elongation at break of 115.17 % with water vapor permeability of 0.48 g·mm·(cm2·h·KPa)-1. The increase of HNK/β-CD content yielded lower optical transmittance and water content of CMC/GG/HIC composite film, while improved the hydrophilicity value. The 2,2-diphenyl-1-picrylhydrazyl radical and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) scavenging capacities of CMC/GG/0.18 % HIC composite film were 80.83 % and 53.10 % respectively. CMC/GG/HIC composite film was bacteriostatic against Staphylococcus aureus and Candida albicans but not against Escherichia coli and Aspergillus niger. Packing strawberries with the optimized composite film can retain the appearance, titratable acidity and vitamin C content of strawberries, which was better than the commercially fresh-keeping film control group. The CMC/GG/HIC composite film overcame the shortcomings of a single material, and gained importance in food packaging applications.

Advancements in Gellan Gum-Based Films and Coatings for Active and Intelligent Packaging

Gellan gum (GG) is a natural polysaccharide with a wide range of industrial applications. This review aims to investigate the potential of GG-based films and coatings to act as environmentally friendly substitutes for traditional petrochemical plastics in food packaging. GG-based films and coatings exhibit versatile properties that can be tailored through the incorporation of various substances, such as plant extracts, microorganisms, and nanoparticles. These functional additives enhance properties like the light barrier, antioxidant activity, and antimicrobial capabilities, all of which are essential for extending the shelf-life of perishable food items. The ability to control the release of active compounds, along with the adaptability of GG-based films and coatings to different food products, highlights their effectiveness in preserving quality and inhibiting microbial growth. Furthermore, GG-based composites that incorporate natural pigments can serve as visual indicators for monitoring food freshness. Overall, GG-based composites present a promising avenue for the development of sustainable and innovative food packaging solutions.

Incorporation of essential oils in polymeric films for biomedical applications

Natural and synthetic biodegradable polymers are widely used to obtain more sustainable films with biological, physicochemical, and mechanical properties for biomedical purposes. The incorporation of essential oils (EOs) in polymeric films can optimize the biological activities of these EOs, protect them from degradation, and serve as a prototype for new biotechnological products. This article aims to discuss updates over the last 10 years on incorporating EOs into natural and synthetic biodegradable polymer films for biomedical applications. Chitosan, alginates, cellulose, and proteins such as gelatine, silk, and zein are among the natural polymers most commonly used to prepare biodegradable films for release EOs. In addition to these, the most cited synthetic biodegradable polymers are poly(L-lactide) (PLA), poly(vinyl alcohol) (PVA), and poly(ε-caprolactone) (PCL). The EOs of clove, cinnamon, tea tree, eucalyptus, frankincense, lavender, thyme and oregano incorporated into polymeric films have been the most studied EOs in recent years in the biomedical field. Biomedical applications include antimicrobial activity against pathogenic bacteria and fungi, anticancer activity, potential for tissue engineering and regeneration with scaffolds and wound healing as dressings. Thus, this article reports on the importance of incorporating EOs into biodegradable polymer films, making these systems especially attractive for various biomedical applications.

Fenugreek seed mucilage-based active edible films for extending fresh fruit shelf life: Antimicrobial and physicochemical properties

Trigonella foenum-graecum, known as fenugreek, belongs to the leguminous family of wild growth in Western Asia, Europe, the Mediterranean, and Asia; its ripe seeds contain a pool of bioactive substances with great potential in the food industry and medicine. In this study, fenugreek seed mucilage (FSM) was extracted and characterized in its structural properties by X-ray diffraction, nuclear magnetic resonance, and high-performance liquid chromatography. Then, the applicability of FSM as an antimicrobial agent was demonstrated via the development of novel, active, edible FSM-based biofilms containing carboxymethyl cellulose and rosemary essential oil (REO). Incorporating REO in the biofilms brought about specific changes in Fourier-transform infrared spectra, affecting thermal degradation behavior. Scanning electron microscopy and atomic force microscopy morphography showed an even distribution of REO and smoother surfaces in the loaded films. Besides, the solubility tests evidenced a reduction in water solubility with increasing REO concentration from 1 to 3 wt%. The biological assay evidenced the antimicrobial activity of REO-loaded biofilms against Staphylococcus aureus and Escherichia coli. Finally, whole apples were dip-coated with FSM-based solutions to showcase future edible systems. The REO-loaded biofilms extended the shelf life of apples to 30 days, demonstrating their potential for sustainable and active coatings.

Fabrication and characterization of emulsion-based edible film containing cinnamon essential oil using chia seed mucilage

Chia seed mucilage (CSM) film incorporated with 2, 4, and 6 % (w/w) nanoemulsion of cinnamon essential oil (CSM-2, CSM-4, CSM-6) were developed, and their physicochemical, mechanical, antioxidant, and antimicrobial properties were determined. According to the results, cinnamon EO nanoemulsion (CEN) had droplet size 196.07 ± 1.39 nm with PDI 0.47 ± 0.04. Moreover, CSM film had higher water solubility (99.37 ± 0.05 %) and WVP (8.55 ± 1.10 g/kPa h m2) than reinforced CSM films with CENCEN. The lowest water solubility (98.02 ± 0.01 %) and WVP (3.75 ± 0.80 g/kPa h m2) was observed in CSM-6 film. Moreover, the addition of CEN improved the homogeneity and density of films and the smoothness of the surface, being observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The Fourier transform infrared (FTIR) spectroscopy also confirmed the incorporation of CEN within the film matrix. The CSM films' antioxidant (DPPH radical scavenging power) and antimicrobial (against Escherichia coli and Staphylococcus aureus) properties of CSM films were notably enhanced with the inclusion of CEN in a dose-dependent manner. The mechanical (tensile strength and elongation at break) of CSM films also was affected by the addition of CEN, TS decreased, and EAB increased (p < 0.05). The lowest TS (20.63 ± 1.39 MPa) and highest EAB (3.36 ± 0.61 %) was observed in CSM-4 film. However, CSM film was relatively dark with low opacity, and adding CEN slightly increased lightness (L*) and yellowness (b*) parameters. The superior antioxidant and barrier characteristics of the CSM edible film incorporated with CEN make it a potential candidate for product packaging and shelf-life extension.