Biodegradable film composition for food packaging

Abstract

Biodegradable film composition for food packaging, comprising the following a) 1% w / v carboxymethyl cellulose as polymer matrix, b) Microemulsions encapsulated in 1 wt% acacia gum, wherein the microemulsions contain 5 wt% Roman chamomile oil, 3 wt% Tween 80 as surfactant and 2 wt% polyethylene glycol as co-surfactant, c) 0.5% (w / v) glycerin as a plasticizer, and d) distilled water as a solvent, wherein the microemulsions improve the antioxidant properties, mechanical flexibility and optical properties of the film while maintaining biodegradability.

Description

[0001] The present invention relates to the composition of microemulsions encapsulated in acacia gum and containing an extract of Roman chamomile (Chamaemelum nobile) for environmentally friendly packaging films. It focuses on the development of sustainable materials with improved biodegradability and functional properties.

[0002] The increasing use of plastic packaging in the food industry has led to significant environmental problems due to its slow decomposition rate and low recycling efficiency. Although plastics offer excellent functional properties such as thermal stability, microwave suitability, and flexibility in shaping, their accumulation in landfills and the marine environment contributes to long-term environmental damage. Since only 21% of plastic waste is recycled or incinerated, the majority remains as persistent pollutants, making the development of sustainable alternatives urgently necessary.

[0003] Biopolymers offer a viable solution to this problem, providing biodegradable and environmentally friendly alternatives for food packaging. Gum arabic (GA), a natural exudate from acacia trees, exhibits exceptional film-forming properties, biocompatibility, and biodegradability, making it an ideal candidate for sustainable packaging applications. Carboxymethylcellulose (CMC), a water-soluble cellulose derivative, has also demonstrated promising barrier properties against oxygen and lipids, while simultaneously exhibiting good mechanical strength and transparency. By utilizing these natural biopolymers, packaging materials can be developed that reduce environmental impact while ensuring food safety.

[0004] To enhance the functional properties of biopolymer-based films, the incorporation of microemulsions offers an innovative approach. Microemulsions are thermodynamically stable colloidal systems that improve film homogeneity, mechanical strength, and barrier properties. In this study, microemulsions encapsulating an extract of Roman chamomile (Chamaemelum nobile) were integrated into CMC-based films to develop sustainable, high-performance food packaging materials. This novel composition aims to improve the durability, biodegradability, and protective properties of biopolymer films, providing an environmentally friendly alternative to conventional plastic packaging.

[0005] One objective of this disclosure is the development of a biodegradable packaging film as an environmentally friendly alternative to conventional plastics.

[0006] Another objective of this disclosure is to improve the antioxidant properties of the film by incorporating microemulsions of Roman chamomile oil.

[0007] Another objective of this disclosure is to improve barrier properties by reducing oxygen and lipid permeability for longer food preservation.

[0008] Another objective of the present disclosure is to ensure the safety of the packaging through the use of natural biopolymers and plant-based ingredients.

[0009] Another objective of this disclosure is to obtain a flexible, transparent and mechanically stable film suitable for food packaging.

[0010] Another objective of the present disclosure is to establish a simple and cost-effective manufacturing process using the casting process with generally available materials.

[0011] Another objective of the present disclosure is to enable individual adaptation of the film formulation for different packaging requirements and food products.

[0012] Another objective of this disclosure is to promote sustainability in the packaging industry through the use of renewable resources and the reduction of plastic waste.

[0013] Further objectives and advantages of the present disclosure will become apparent from the following description, which is not intended to limit the scope of the present disclosure. The present invention relates to the composition of biodegradable food packaging films formulated using carboxymethylcellulose (CMC) as a base material.

[0014] Another embodiment of the present invention is the production of the film composition by the casting process, wherein glycerin serves as a plasticizer to improve flexibility and processability.

[0015] Another embodiment of the present invention is the evaluation of the film composition by microscopic imaging methods for investigating the surface morphology and the microemulsion dispersion.

[0016] Another embodiment of the present invention is the evaluation of the functional properties of the composition, including light transmission, turbidity, tensile strength and elongation at break.

[0017] Another embodiment of the present invention is the measurement of the film thickness of the composition with a digital caliper, while the color parameters were analyzed with a chroma meter.

[0018] Another embodiment of the present invention is the determination of the antioxidant potential of the films loaded with the microemulsion by the ABTS radical scavenger test.

[0019] Another embodiment of the present invention is the evaluation of the developed biopolymer composite film as a sustainable and environmentally friendly alternative to conventional plastic packaging for food.

[0020] The present invention relates to the composition of biodegradable food packaging films using carboxymethylcellulose (CMC) as the primary biopolymer matrix, reinforced with microemulsions of Roman chamomile oil encapsulated in gum arabic (GA). This composition contains glycerin as a plasticizer to improve flexibility and mechanical properties. The films are produced by a casting method in which a homogeneous film-forming solution is prepared, poured into Petri dishes, and dried under controlled conditions. The incorporation of microemulsions into the composition is intended to improve the functional properties of the films, including structural integrity and antioxidant potential.

[0021] Within the scope of the invention, the morphological, mechanical, optical, and functional properties of the developed composition are further investigated to evaluate its suitability for food packaging applications. Various characterization techniques, including gas chromatography-mass spectrometry (GC-MS), microscopy, tensile strength analysis, and antioxidant tests, are employed to evaluate the composition and properties of the films. The integration of microemulsions is expected to influence the film's thickness, transparency, color properties, and flexibility, while simultaneously enhancing its protective functions. This innovative composition offers a sustainable and environmentally friendly alternative to conventional plastic packaging, addressing concerns regarding pollution and food preservation. EXAMPLE 1: Composition

[0022] Biodegradable film composition for food packaging, comprehensive a) 1% (w / v) carboxymethyl cellulose as polymer matrix, b) Microemulsions encapsulated in 1% w / v acacia gum, wherein the microemulsions contain 5% w / v Roman chamomile oil, 3% w / v Tween 80 as a surfactant and 2% w / v polyethylene glycol (Peg 400) as a co-surfactant, c) 0.5% (w / v) glycerin as a plasticizer, and d) distilled water as a solvent, wherein the microemulsions improve the antioxidant properties, mechanical flexibility and optical properties of the film while maintaining biodegradability. EXAMPLE 2: Production of microemulsions

[0023] Microemulsions were prepared using the oil-in-water method. The oil phase was first formulated by mixing 5 ml of Roman chamomile oil, 3 ml of Tween 80 (surfactant), and 2 ml of PEG 400 (co-surfactant) in a small beaker with continuous stirring at moderate heat. Simultaneously, the aqueous phase was prepared by dissolving 1 gram of gum arabic (GA) in 100 ml of distilled water at 30 °C to obtain a 1% (w / v) solution. Once the gum arabic solution was completely homogenized, the oil phase was added dropwise with continuous stirring until a uniform microemulsion suspension was obtained. EXAMPLE 3; Filmmaking

[0024] Microemulsion-loaded CMC-based biopolymer films were prepared using a casting method with glycerol as a plasticizer. First, a 1% w / v solution was prepared by dissolving 1 gram of CMC in 100 ml of distilled water at 30°C and stirring until complete homogenization. The microemulsions were then incorporated into the solution, which was divided between two beakers. One beaker contained only the CMC solution with 0.5% glycerol (as a plasticizer) and was designated GA1 (control), while the other formulations contained both plasticizers and microemulsions. After thorough mixing, 20 ml of each film-forming solution were poured into labeled plastic Petri dishes (90 × 15 mm) and dried for 48 hours at 25°C. After drying, the films were carefully peeled from the Petri dishes and subjected to further analysis. EXAMPLE 4: Gas Chromatography

[0025] Gas chromatography-mass spectrometry (GCMS) analysis was performed using a gas chromatograph-mass spectrometer. A 1 µl sample was injected at a split ratio of 1:115, and the column temperature was initially set to 50 °C for 2 minutes, then increased to 210 °C at a rate of 3 °C per minute, followed by a further increase to 280 °C at 6 °C per minute. Helium was used as the carrier gas at a flow rate of 1.0 mL / min, while the injector and ion source temperatures were maintained at 260 °C and 220 °C, respectively. The bioactive compounds were identified by comparing the retention indices and retention times (RT) with true reference standards.

[0026] The results show that GC-MS analysis of Roman chamomile oil identified 31 bioactive compounds, each with different retention times and molecular weights, contributing to its characteristic aroma and potential therapeutic properties. The most abundant compound was diethyl phthalate (36.43%), followed by bis(2-ethylhexyl) phthalate (18.79%), linalool (6.52%), and phenylmethyl acetic acid (7.69%). Other important constituents included benzene, 1-methoxy-4-(1-propenyl)-(Z) (5.99%), α-terpineol (4.56%), dipropylene glycol (isomer 2) (1.63%), and cinnamaldehyde, α-pentyl- (1.22%), all of which contribute to the oil's fragrance and potential biological activity. EXAMPLE 5: Characterizations

[0027] The results of the visual appearance analysis of the produced films show that the control film sample (CM1) was sticky and difficult to peel, but exhibited a smooth, transparent, and uniform texture with a glossy appearance. In contrast, the microemulsion-loaded CM2 film samples were easier to peel and had a smoother, more uniform, and more flexible texture than the control sample. Overall, the incorporation of microemulsions resulted in significant differences in surface morphology between the modified films and the control samples.

[0028] Morphological characteristics: The images were acquired using an AmScope MU1803 microscope digital camera, which was connected to a compatible computer via USB 3.0 for data acquisition. The camera's advanced ultra-fine color engine delivered high-resolution images with improved color accuracy and vibrancy.

[0029] The results show that microscopic images of the film samples at 40x magnification reveal a heterogeneous structure with dispersed microemulsions uniformly embedded in the polymer matrix. The droplets retained their round shape, indicating the preservation of structural integrity during film formation, which is crucial for the controlled release and functionality of bioactive compounds. However, the slight aggregation observed in certain areas suggests local phase separation, which may be influenced by factors such as polymer concentration, drying conditions, or the composition of the microemulsion.

[0030] Layer thickness: The thickness of the developed film samples was measured using a digital caliper. Each film sample was measured at four different points, and the average thickness was calculated and expressed in millimeters.

[0031] The results show that the incorporation of microemulsions significantly increases the film thickness from 0.11 mm in the control sample to 0.34 mm. This increase is likely due to the higher solids content remaining in the film-forming solution after dehydration, as well as the more porous microstructure of the microemulsion-coated films.

[0032] Light transmission and haze value: The light transmission of the produced film samples was evaluated using a YH1200 haze meter. Three measurements were taken on different sections of each film sample, and the average value was calculated.

[0033] Transmittance measures the proportion of light that passes through a polymer, while opacity refers to the percentage of scattered transmitted light. Lower opacity values ​​improve packaging clarity and enhance product visibility. The results show that adding microemulsions to the film matrix reduces transmittance and increases opacity. The CM1 control film had a transmittance of 92.23% and an opacity of 34.87%, while the CM2 film with microemulsions exhibited a lower transmittance of 88.98% and a significantly higher opacity of 88.41%.

[0034] Mechanical properties: The tensile properties of the films were analyzed using a texture analyzer equipped with a 10 kg load cell. The tensile test was performed according to ASTM D882, and Exponent Connect software was used to extract the results, including the tensile strength (TS) in megapascals (MPa) and the percentage of elongation at break (EAB) from the stress-strain curves.

[0035] The results show that the tensile strength of the biopolymer films did not decrease significantly from 0.01 MPa in the control sample (CM1) to 0.004 MPa with the incorporation of the microemulsions. The elongation at break (EAB), which measures the ductility of a film, also decreased. The control sample exhibited an EAB of 104.16%, while the films loaded with microemulsions showed a reduced value of 87.04%. This reduction in tensile strength and EAB can be attributed to the higher plasticizer content in the microemulsion-loaded films.

[0036] Color properties of the films: The color properties of the films were evaluated using a Chroma Meter (CR-410) from Konica Minolta, Inc., Japan. The analysis included measuring the brightness (L), the green-red (a), and the blue-yellow (b) values ​​to assess the color properties of the films. ΔE=ΔL2+Δa2+Δb2 ΔL*, Δa* and Δb* represent color differences between the film samples and the standard (L* = 95.9, a* = -0.09, b* = 0.1).

[0037] The results show that the incorporation of microemulsions altered the optical properties of the films. The CM1 sample had a higher brightness (L* = 0.15) than the CM2 sample (-2.08), likely due to light-absorbing components in the microemulsion matrix. Both samples exhibited negative a* values, but CM2 (-0.26) was more negative than CM1 (-0.01), giving it a greener tint. A significant increase in the b* value was observed, with CM2 (0.40) appearing more yellow than CM1 (0.02). The total color difference (ΔE) was significantly higher for CM2 (2.14) than for CM1 (0.22), confirming that the microemulsions substantially influence the overall color properties of the films. EXAMPLE 6: Assessment of the antioxidant effect

[0038] The antioxidant activity of the film samples was evaluated using the ABTS cation scavenger assay. The ABTS radical neutralization potential was determined by measuring the absorption shift at 734 nm after a six-minute integration time. For the analysis, 10 mg of the film sample was mixed with 1.9 mL of a 7 mmol / L ABTS radical solution, and the results were expressed as the percentage of ABTS radical inhibition. The percentage of inhibition was calculated using standard formulas.

[0039] The results show that the ABTS radical scavenging activity of the film samples increased significantly from 12.57% in the control group (CM1) to 31.97% in the microemulsion-loaded films (CM2). The lower antioxidant activity in CM1 was due to the absence of bioactive compounds, while the higher activity in CM2 was likely attributable to the antioxidant properties of the Roman chamomile oil encapsulated in the microemulsions.

[0040] Statistical analysis: Means and standard errors were derived from three independent experiments. A one-sided ANOVA followed by a Duncan multi-range test at a significance level of 5% was performed to identify significant differences between the means. Examples

[0041] 1. Biodegradable film composition for food packaging, comprising the following a) 1% w / v carboxymethyl cellulose as polymer matrix, b) Microemulsions encapsulated in 1 wt% acacia gum, wherein the microemulsions contain 5 wt% Roman chamomile oil, 3 wt% Tween 80 as surfactant and 2 wt% polyethylene glycol as co-surfactant, c) 0.5% (w / v) glycerin as a plasticizer, and d) distilled water as a solvent, wherein the microemulsions improve the antioxidant properties, mechanical flexibility and optical properties of the film while maintaining biodegradability.

Claims

[1] Biodegradable film composition for food packaging, comprising a) 1% w / v carboxymethyl cellulose as polymer matrix, b) microemulsions encapsulated in 1 wt% acacia gum, the microemulsions containing 5 wt% Roman chamomile oil, 3 wt% Tween 80 as surfactant and 2 wt% polyethylene glycol as co-surfactant, c) 0.5% (w / v) glycerin as a plasticizer, and d) distilled water as a solvent, whereby the microemulsions improve the antioxidant properties, mechanical flexibility and optical properties of the film while maintaining biodegradability. [2] Biodegradable film composition for food packaging according to claim 1, wherein the microemulsions are uniformly dispersed in the carboxymethylcellulose matrix at a concentration of 20% v / v to improve the homogeneity of the film. [3] The biodegradable film composition for food packaging according to claim 1, wherein the microemulsions reduce the film permeability from 92.23% to 88.98% and increase the haze value from 34.87% to 88.41%. [4] A biodegradable film composition for food packaging according to claim 1, wherein the incorporation of microemulsions reduces the tensile strength of the film from 0.01 MPa to 0.004 MPa while maintaining an elongation at break of 87.04%. [5] Biodegradable film composition for food packaging according to claim 1, wherein the film thickness increases from 0.11 mm in the control sample to 0.34 mm by the addition of microemulsions. [6] The biodegradable film composition for food packaging according to claim 1, wherein the antioxidant activity, as measured by ABTS radical scavenging activity, increases from 12.57% in the control sample to 31.97% in the microemulsion-loaded film. [7] A biodegradable film composition for food packaging according to claim 1, wherein the color parameters of the film change with L* decreasing from 0.15 to -2.08, a* becoming more negative from -0.01 to -0.26, and b* increasing from 0.02 to 0.

40. [8] A biodegradable film composition for food packaging according to claim 1, wherein the film is suitable for food packaging applications due to its improved barrier properties, mechanical flexibility and increased antioxidant activity.