Biodegradable biopolymer film composition for active food packaging

Abstract

Biodegradable biopolymer film composition for packaging active foods, including: a) 2% (w / v) polyvinyl alcohol (PVA) as a film-forming matrix; b) 0.4% w / v essential oil of cumin (Cuminum cyminum) and 0.4% w / v essential oil of coriander (Coriandrum sativum) as active agents for improved antioxidant properties; c) 0.5% (w / v) glycerin as a plasticizer to improve flexibility and mechanical properties; d) 0.8% (w / v) Tween 80 as a surfactant to promote the uniform dispersion of the essential oils in the polymer matrix; e) wherein the film has a thickness in the range of 0.08 mm to 0.14 mm, an increase in turbidity of up to 14.05%, an increase in radical scavenging activity of up to 30.77% and an improved water contact angle of up to 46.12°, thereby providing improved mechanical strength, hydrophobicity and opacity suitable for food packaging applications.

Description

[0001] The present invention relates to a biodegradable biopolymer film composition intended for the packaging of active foods. It contains a polyvinyl alcohol (PVA) composition with a binary combination of cumin and coriander essential oils, glycerin as a plasticizer, and Tween 80 as a surfactant. This film improves food preservation through antioxidant, antimicrobial, and moisture-resistant properties.

[0002] The growing reliance on plastic-based packaging materials has led to serious environmental problems, including plastic pollution, which threatens ecosystems, marine life, and public health. While conventional plastic packaging preserves the quality of food, it contributes significantly to waste generation due to its lack of biodegradability. Given the increasing global awareness of sustainability issues, there is an urgent need to develop alternative packaging materials that are biodegradable, environmentally friendly, and can preserve food freshness. Biopolymer-based films derived from renewable sources offer a promising solution, as they decompose naturally without leaving harmful residues.However, many biopolymers lack the necessary mechanical strength and barrier properties required for effective food packaging, necessitating further improvement through material modifications.

[0003] Active packaging has proven to be a viable approach to improving food preservation by incorporating functional additives that extend shelf life and maintain product quality. Essential oils (EOs), known for their antimicrobial and antioxidant properties, have gained attention as natural preservatives for use in bio-based packaging. However, individual essential oils often have limitations regarding stability, efficacy, or compatibility with polymer matrices. Combining multiple essential oils in a single formulation has the potential to overcome these challenges by enhancing synergistic effects, improving antimicrobial efficacy, and optimizing the functional properties of biopolymer films.In particular, the essential oils of coriander and cumin have been extensively studied for their strong antimicrobial and antioxidant properties, making them ideal candidates for incorporation into biodegradable films.

[0004] This invention focuses on the development of an advanced biopolymer-based packaging film by integrating poly(vinyl alcohol) (PVA) with a binary combination of coriander and cumin essential oils. PVA is a widely used polymer due to its excellent film-forming ability, water solubility, and non-toxicity, making it an ideal matrix for active packaging applications. Through the addition of coriander and cumin essential oils, this novel film is expected to improve the water barrier properties, antioxidant activity, and overall functionality of the packaging material. This innovation not only addresses the problem of plastic pollution but also provides an effective, sustainable, and biodegradable packaging alternative that meets modern consumer demands for safer and environmentally friendly food packaging solutions.

[0005] Some of the objects of the present disclosure, which are met by at least one embodiment, are the following.

[0006] An object of the present disclosure is to produce a biodegradable biopolymer film containing a binary combination of essential oils of cumin and coriander for the packaging of active foods.

[0007] Another object of the present disclosure is to improve food preservation by providing antioxidant properties.

[0008] Another object of the present disclosure is to provide a biodegradable and environmentally friendly alternative to synthetic packaging.

[0009] Another objective of the present disclosure is to improve mechanical strength and flexibility for better durability.

[0010] Another object of the present disclosure is to improve the surface properties of the films produced and to make them more hydrophobic.

[0011] Another object of the present disclosure is to produce a biodegradable, environmentally friendly packaging material that reduces food spoilage and extends its shelf life.

[0012] Another object of the present disclosure is to provide a safer packaging solution by minimizing synthetic additives.

[0013] Another objective of the present disclosure is to improve visual appeal through improved optical and color properties.

[0014] Another objective of this disclosure is compatibility with various foods due to their natural composition.

[0015] Further objects 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

[0016] The present invention relates to the composition of a biodegradable biopolymer film consisting of polyvinyl alcohol (PVA), glycerin, Tween 80 and a binary combination of essential oils of cumin and coriander.

[0017] A further embodiment of the present invention is that the film is intended for food packaging and has improved antioxidant properties to extend the shelf life of perishable foods.

[0018] Another embodiment of the present invention is the incorporation of cumin and coriander oils, which improves the functional properties of the film by introducing bioactive compounds with natural preservative capabilities.

[0019] Another embodiment of the present invention is that the film has improved tensile strength while maintaining sufficient flexibility, making it suitable for various packaging applications.

[0020] Another embodiment of the present invention is the addition of essential oils, which increases the hydrophobicity of the film, reduces moisture absorption and improves its barrier properties.

[0021] Another embodiment of the present invention is that the film has reduced light transmission and increased haze, which helps protect packaged food from light-induced spoilage.

[0022] A further embodiment of the present invention is the presence of essential oils, which significantly increase the radical scavenging activity of the film and thus contribute to better preservation of the food.

[0023] Another embodiment of the present invention is that the film is biodegradable and environmentally friendly and represents a viable alternative to conventional plastic packaging materials.

[0024] The present invention relates to the development of a biodegradable biopolymer film composition for active food packaging containing a binary combination of caraway and coriander essential oils in a polyvinyl alcohol (PVA) matrix. The film is produced by a casting process, with glycerin serving as a plasticizer and Tween 80 as a surfactant. This innovative composition improves the flexibility, durability, and functional properties of the film, making it suitable for sustainable food packaging.

[0025] The addition of essential oils not only improves the film's mechanical strength and water resistance, but also provides antioxidant protection. As an environmentally friendly alternative to conventional plastic packaging, this biopolymer film composition reduces environmental impact while preserving food freshness and safety. Its biodegradability and improved barrier properties make it a promising material for extending the shelf life of perishable foods. EXAMPLE 1: COMPOSITION

[0026] Biodegradable biopolymer film composition for active packaging of food, comprising: a) 2% (w / v) polyvinyl alcohol (PVA) as film-forming matrix; b) 0.4% (w / v) essential oil of cumin (Cuminum cyminum) and 0.4% (w / v) essential oil of coriander (Coriandrum sativum) as active agents for enhanced antioxidant properties; c) 0.5% (w / v) glycerin as a plasticizer to improve flexibility and mechanical properties; d) 0.8% (w / v) Tween 80 as a surfactant to promote the uniform dispersion of the essential oils in the polymer matrix. EXAMPLE 2: Production of films

[0027] The casting method was used to prepare polyvinyl alcohol loaded with a binary combination of cumin and coriander oil, with glycerin as a plasticizer and Tween 80 as a surfactant in biocomposite film samples. First, a 2% (w / v) solution was prepared by dissolving 2 grams of PVA in 100 ml of distilled water at 30°C. After complete homogenization of the PVA in the distilled water, the essential oils were mixed. The homogeneous solution was then divided into two beakers. The beaker containing only the PVA solution without the addition of essential oils was designated PB1 (control) and contained 0.5% glycerin (as a plasticizer), while the other formulations were loaded with plasticizer and 0.4% cumin and 0.4% coriander oil, along with 0.8% Tween 80.After mixing the film-forming solutions, 20 ml of solution from each baker was poured into labeled plastic Petri plates (90 × 15 mm) and dried at 25 °C for 48 hours. After film formation, the films were carefully removed from the Petri dishes and subjected to further analysis. EXAMPLE 3: Gas Chromatography-Mass Spectrometry (GC-MS)

[0028] The composition of cumin and coriander essential oils was analyzed using a GCMS-QP-2010 Plus gas chromatograph-mass spectrometer. For cumin oil, 1 µL was injected with a split ratio of 1:115, and the temperature program was set from 50°C (held for 2 minutes) to 210°C (at 3°C / min) and then further increased to 280°C (at 6°C / min). Helium was used as the carrier gas at a constant flow rate of 1.0 mL / min. The injector and ion source temperatures were maintained at 260°C and 220°C, respectively. Bioactive compounds were identified by comparing retention times (RT) and indices with reference standards, and the same method was applied for the analysis of coriander oil.

[0029] GC-MS analysis of cumin oil identified a total of 57 bioactive compounds, highlighting its complex chemical composition. The most abundant compound was benzaldehyde, 4-(1-methylethyl), which accounted for 38.19% of the total composition, followed by γ-terpinene (18.19%), o-cymene (16%), and β-pinene (14.02%). Additionally, minor components such as α-pinene (2.99%), β-myrcene (1.50%), and (-)-myrtenol (1.08%) contributed to the overall aroma and potential biological activity of the oil.

[0030] Similarly, GC-MS analysis of coriander oil identified 40 different compounds, including monoterpenes, sesquiterpenes, and oxygenated compounds. The most important component was diethyl phthalate, which accounted for 76.51% of the total composition, followed by linalool (13.61%) and bicyclo[2.2.1]heptan-2-one, 1,7,7-trimethyl-, (1S)- (2.29%). Other minor compounds such as 3-carene (0.62%), o-cymene (0.31%), and d-limonene (0.20%) contributed to the characteristic aroma and biological activity of the oil. EXAMPLE 4: Characterizations

[0031] Visual analysis of the film samples after peeling revealed a homogeneous and uniform structure across all formulations. The control sample (PB1) exhibited better visual properties compared to the PB2 film sample; however, the PB2 films were easier to peel from the Petri plates. Furthermore, PB2 exhibited greater stiffness, flexibility, brittleness, and rigidity, while PB1 was significantly more sticky. The incorporation of a binary combination of essential oils into the PB2 film matrix contributed to increased fragility and distinguished it from the other formulations. Layer thickness

[0032] The thickness of the developed films was measured using a Deguqmnt digital display caliper. Each film sample was measured at four different locations, and the average value was recorded in millimeters.

[0033] The thickness results of the PB film samples showed a significant increase, with PB1 measuring 0.08 mm and PB2 measuring 0.14 mm. This thickness variation is likely due to the accumulation of essential oil droplets in the film matrix. Light transmittance and haze value

[0034] The optical properties of the films, including transmittance and haze, were evaluated using a YH1200 Haze Meter. Three readings were taken from different sections of each film sample, and the average values ​​were calculated.

[0035] The results show that the transmittance of the PB biocomposite films decreased significantly from 93.18% (PB1) to 92.00% (PB2), while the haze value increased significantly from 0.38% to 14.05%. The incorporation of essential oils resulted in increased light scattering within the film network. A higher concentration of oil droplets contributed to lower light transmittance and increased turbidity. The extent of these changes depended on the size and distribution of the particles of the dispersed phase. Similar trends were observed in previous studies with the addition of phenols, lipids, or essential oils. Mechanical properties

[0036] Tensile strength (TS) and elongation at break (EAB) were measured using a Texture Analyzer TA.XT plus C with a 10 kg load cell according to ASTM D882. Exponent Connect software was used to extract stress-strain curve data, allowing direct measurements of the mechanical properties.

[0037] The results show that the tensile strength (TS) of the PB biocomposite films increased significantly from 0.007 MPa to 0.015 MPa with the addition of essential oils. The elongation at break (EAB) decreased significantly from 361.9% to 98.4%, with PB1 films exhibiting greater flexibility than PB2 films. Compared to PB1, the PB2 samples exhibited higher tensile strength and lower elongation at break. The PB1 films exhibited lower tensile strength and higher elongation at break, indicating greater flexibility and extensibility. Color properties of the films

[0038] The color properties of the films, including brightness (L*), green-red (a*), and blue-yellow (b*), were analyzed using a chroma meter (CR-410, Konica Minolta, Japan). The total color difference (ΔE) was calculated using the following formula: ΔE=(ΔL2+Δa2+Δb2) where ΔL*, Δa* and Δb* represent the color differences between the film samples and the standard reference (L* = 95.9, a* = -0.09, b* = 0.1).

[0039] The results show that the L value of PB1 films was higher (0.94) than that of PB2 films (0.62), indicating greater brightness and transparency for PB1. Both films exhibited negative a* values, with PB1 (-0.11) and PB2 (-0.34) indicating a slightly greenish hue. The b* value was positive for both, with PB2 (1.42) appearing more yellow than PB1 (0.16). The overall color difference (ΔE) was higher for PB2 (1.58) than for PB1 (0.97), indicating a significant color shift. These differences were attributed to the incorporation of the essential oils into the film matrix. Antioxidant rating

[0040] The antioxidant activity of the films was determined using the ABTS cation scavenging assay. The ability to scavenge ABTS radicals was assessed by measuring absorbance changes at 734 nm over a period of six minutes. A 10 mg film sample was mixed with 1.9 ml of a 7 mmol / L ABTS radical scavenging solution, and the percent inhibition was calculated using the following formula: Ac Percent inhibition (%) = (AC−At)AC×100 where Ac is the absorbance of the control solution and At is the absorbance of the sample solution.

[0041] Free radical scavenging activity increased with the incorporation of essential oils into the film matrix. PB1 films showed the lowest activity (17.72%) due to the lack of antioxidant compounds, while PB2 films exhibited significantly higher activity (30.77%). This increase was attributed to the presence of bioactive compounds in cumin and coriander oil. The essential oils contributed phenols, flavonoids, and terpenes, enhancing the antioxidant properties. Water contact angle

[0042] The hydrophobicity of the films was analyzed using an OCA11 contact angle analyzer (DataPhysics Instruments GmbH, Germany). A 2 × 2 cm film sample was placed on the platform, and a 1.0 µl drop of distilled water was carefully applied. The contact angle was measured in triplicate using dpiMAX software, and images of the water droplet on the film surface were captured with a high-resolution camera (1044 × 1080).

[0043] The results show that the water contact angle of PB1 films was significantly lower at 37.05° (left) and 34.13° (right) than that of PB2 films at 46.12° (left) and 45.12° (right). This suggests that the PB1 films are inherently hydrophilic, which may be due to the hydrophilic nature of PVA. The incorporation of essential oils into PB2 films increased the water contact angle, thereby improving their water resistance. This improvement is beneficial for food packaging that requires moisture barriers. Statistical analysis

[0044] All experiments were performed in triplicate, and results were expressed as mean ± standard error. Statistical differences between means were determined using a one-way ANOVA followed by Duncan's multiple-range test at a significance level of 5%. Examples 1. A biodegradable biopolymer film composition for packaging active foods, comprising: a) 2% (w / v) polyvinyl alcohol (PVA) as film-forming matrix; b) 0.4% (w / v) essential oil of cumin (Cuminum cyminum) and 0.4% (w / v) essential oil of coriander (Coriandrum sativum) as active agents for enhanced antioxidant properties; c) 0.5% (w / v) glycerin as a plasticizer to improve flexibility and mechanical properties; d) 0.8% (w / v) Tween 80 as a surfactant to promote the uniform dispersion of the essential oils in the polymer matrix; e) wherein the film has a thickness in the range of 0.08 mm to 0.14 mm, an increase in haze value of up to 14.05%, an increase in radical scavenging activity of up to 30.77% and an improved water contact angle of up to 46.12°, thereby providing improved mechanical strength, hydrophobicity and opacity suitable for food packaging applications.

Claims

[1] Biodegradable biopolymer film composition for packaging active foods, comprising: a) 2% (w / v) polyvinyl alcohol (PVA) as film-forming matrix; b) 0.4% (w / v) essential oil of cumin (Cuminum cyminum) and 0.4% (w / v) essential oil of coriander (Coriandrum sativum) as active agents for enhanced antioxidant properties; c) 0.5% (w / v) glycerin as a plasticizer to improve flexibility and mechanical properties; d) 0.8% (w / v) Tween 80 as a surfactant to promote the uniform dispersion of the essential oils in the polymer matrix; e) wherein the film has a thickness in the range of 0.08 mm to 0.14 mm, an increase in haze value of up to 14.05%, an increase in radical scavenging activity of up to 30.77% and an improved water contact angle of up to 46.12°, thereby providing improved mechanical strength, hydrophobicity and opacity suitable for food packaging applications. [2] The biodegradable biopolymer film composition according to claim 1, wherein the essential oils are uniformly dispersed in the polymer matrix due to the presence of Tween 80 as a surfactant. [3] The biodegradable biopolymer film composition of claim 1, wherein the increased thickness is due to the accumulation of droplets of essential oils within the film structure. [4] The biodegradable biopolymer film composition according to claim 1, wherein the opacity of the film is increased due to the light scattering caused by the dispersed essential oil droplets, which improves the UV protection for packaged food products. [5] The biodegradable biopolymer film composition according to claim 1, wherein the radical scavenging activity is due to the phenolic and flavonoid compounds present in the essential oils of cumin and coriander. [6] The biodegradable biopolymer film composition of claim 1, wherein the increased water contact angle enhances the hydrophobic properties of the film, making it suitable for packaging applications requiring reduced water permeability.