Biodegradable food packaging composition containing Akba derivative-reinforced Gelrit-Gellan rubber composites

Abstract

Biodegradable food packaging composition comprising Gelrit gellan gum composites reinforced with an AKBA derivative (SK-C5), the composition comprising: a) Gelrit gellan gum in an amount of 1% w / v, b) Glycerol in an amount of 0.5% w / v, c) (1-(4-Methoxyphenyl)-1h-1,2,3-triazol-4-yl)methyl)carbamoyl) 3α-acetyloxy-11-oxo-urs-12-en-24-oate (sk-c5) in an amount of 0.1 wt. / vol, d) distilled water in an amount that balances to 100%, the composition having improved mechanical properties, antioxidant activity and hydrophobicity, making it suitable for sustainable packaging applications.

Description

[0001] The present invention relates to biodegradable packaging compositions, in particular Gelrit gellan gum composites reinforced with an AKBA derivative (SK-C5). It relates to the development of sustainable, bioactive films with improved mechanical, optical, and antioxidant properties. These compositions are intended for food packaging and other environmentally friendly applications.

[0002] Food packaging plays a crucial role in ensuring the safety, hygiene, and longevity of food by preventing contamination, spoilage, and physical damage. However, the widespread use of conventional plastic packaging has raised serious environmental concerns, as it is non-biodegradable and contributes to global plastic waste. As a result, there is a growing demand for sustainable and biodegradable alternatives that provide the necessary protective features while reducing environmental impact. Natural polymers, or biopolymers, have emerged as promising replacements for petroleum-based plastics because they are biodegradable, renewable, and safe for food-contact applications.However, their practical use is often limited by weak mechanical strength, poor barrier properties and insufficient antimicrobial activity, so further modifications are required to improve their functional performance.

[0003] Gellan gum, a polysaccharide obtained through microbial fermentation, is one such biopolymer that has been extensively researched for food packaging applications. Gellan gum is classified as safe by the U.S. Food and Drug Administration (FDA) and exhibits excellent biocompatibility, solubility, and biodegradability, making it an attractive candidate for environmentally friendly packaging solutions. However, pure gellan gum films have structural limitations, including brittleness, low tensile strength, and insufficient resistance to moisture and microbial contamination.

[0004] To address these challenges, researchers have investigated composite formulations containing plasticizers, reinforcing agents, and bioactive compounds to improve the mechanical and functional properties of gellan gum-based films. One promising approach is the incorporation of active compounds such as antioxidants and antimicrobials, which can improve the barrier properties of packaging films while providing additional benefits such as food preservation and extended shelf life.

[0005] In this context, boswellic acids, natural pentacyclic triterpenes derived from the gum resin of Boswellia sacra, offer significant potential as bioactive additives in biodegradable films. Among these, 3-O-acetyl-11-keto-β-boswellic acid (AKBA) has demonstrated promising pharmacological effects, including antioxidant and antimicrobial properties. By incorporating AKBA into Gelrit-gellan composite films, it is possible to develop an advanced biodegradable packaging material with increased mechanical integrity, improved barrier properties, and functional bioactivity.

[0006] Some of the objects of the present disclosure, which at least one embodiment fulfills herein, are as follows.

[0007] An object of the present disclosure is the produced film which is environmentally friendly and decomposes naturally, thereby reducing plastic waste.

[0008] Another object of the present disclosure is the incorporation of SK-C5, which improves tensile strength and flexibility.

[0009] Another objective of the present disclosure is that the AKBA derivative (SK-C5) improves the film's ability to protect packaged products from oxidation. Another objective of the present disclosure is that the SK-C5-loaded film exhibits hydrophobic properties to improve the shelf life of the package.

[0010] Another object of the present disclosure is the developed film that enables uniform transparency for aesthetic and functional packaging requirements.

[0011] Another object of the present disclosure is to produce a biopolymer and natural bioactive compounds that ensure the safety of food packaging.

[0012] Another object of the present disclosure is the formulation that supports easy film casting and processing at ambient conditions.

[0013] Another objective of the present disclosure is that the bioactive-loaded film provides functional benefits beyond protection, such as extended shelf life.

[0014] 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.

[0015] The present invention relates to the development of a biodegradable packaging film using Gelrit gellan gum as the primary polymer matrix.

[0016] Another embodiment of the present invention is the polymer matrix with (1-(4-methoxyphenyl)-1H-1,2,3-triazol-4-yl)methyl)carbamoyl) 3α-acetyloxy-11-oxo-urs-12-en-24-oate (SK-C5) derived from AKBA.

[0017] Another embodiment of the present invention is the introduction of glycerin as a plasticizer to improve flexibility and reduce brittleness.

[0018] Another embodiment of the present invention is the film-forming solution prepared by a casting process and dried at controlled temperature and humidity.

[0019] In a further embodiment of the present invention, the prepared solution is poured into Petri dishes and dried under controlled temperature conditions to achieve uniform film formation.

[0020] In another embodiment of the present invention, the films are dried at 25°C for 48 hours to ensure good structure and easy removability.

[0021] Another embodiment of the present invention is the incorporation of SK-C5, which contributes to increased water resistance, making the films suitable for packaging applications.

[0022] Another embodiment of the present invention is that the composition is designed to be biodegradable and to provide an environmentally friendly alternative to synthetic packaging materials.

[0023] The present invention relates to the development of biodegradable packaging films using Gelrit gellan gum composites reinforced with a boswellic acid derivative, namely (1-(4-methoxyphenyl)-1H-1,2,3-triazol-4-yl)methyl)carbamoyl) 3α-acetyloxy-11-oxo-urs-12-en-24-oate (SK-C5). The films were prepared by a casting process, using glycerin as a plasticizer to improve flexibility and mechanical properties. The composition contains Gelrit gellan gum as a biopolymer matrix, which provides structural integrity and film-forming properties. SK-C5, a bioactive compound derived from β-AKBA, was incorporated into the film matrix to impart additional functional properties. The films were dried under controlled conditions to ensure uniform formation and easy release from the cast surface.

[0024] The invention aims to create a sustainable and functional alternative to conventional plastic packaging by integrating natural biopolymers with bioactive reinforcing agents. The formulation is designed to strike a balance between mechanical strength, flexibility, transparency, and water resistance, while also incorporating bioactive properties for potential antioxidant effects. The developed films are intended for food packaging and offer a biodegradable, safe, and environmentally friendly solution. EXAMPLE 1: COMPOSITION

[0025] A biodegradable food packaging composition comprising Gelrit gellan gum composites reinforced with (1-(4-methoxyphenyl)-1H-1,2,3-triazol-4-yl)methyl)carbamoyl) 3α-acetyloxy-11-oxo-urs-12-en-24-oate (SK-C5), the composition comprising: a) Gelrit gellan gum in an amount of 1% w / v, b) Glycerin in an amount of 0.5% w / v, c) (1-(4-Methoxyphenyl)-1H-1,2,3-triazol-4-yl)methyl)carbamoyl) 3α-acetyloxy-11-oxo-urs-12-en-24-oate (SK-C5) in an amount of 0.1% w / v, d) Distilled water in an amount of 100%, the composition exhibiting improved mechanical properties, antioxidant activity and hydrophobicity, making it suitable for sustainable packaging applications. EXAMPLE 2: Synthesis of (Prop-2-yn-1-ylcarbamoyl) 3α-Acetyloxy-11-oxo-urs-12-en-24-oate (3)

[0026] A solution of β-AKBA (1) (1.0 equiv.) mixed with HATU (1.2 equiv.) in anhydrous DMF was combined with propargylamine (2) (1.1 equiv.) and DIPEA (2.5 equiv.). This mixture was stirred at room temperature for 10 to 12 hours, with the reaction progress monitored by TLC. After completion of the reaction, it was extracted with ethyl acetate, dried over MgSO4, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using n-hexane / ethyl acetate (85:15 v / v) as eluent. Recrystallization from methanol afforded the final compound 3 as light green crystals in 94% yield and a melting point of 196 to 198 °C. Structural characterization was confirmed by spectroscopic analyses, including 1 H NMR, 13 C NMR and HRMS, confirming the molecular formula C 35 H 32 NO4 with a molecular ion peak at m / z 550.39124 ([M+H] + ) confirmed. BEISPIEL 3: Synthese von (1-(4-Methoxyphenyl)-1H-1,2,3-triazol-4-yl) methyl) carbamoyl) 3α-acetyloxy-11-oxo-urs-12-en-24-oat (5) (SK-C5)

[0027] A solution containing compound 3 (1.0 equiv.) and 4-methoxyphenyl azide (4) (1.2 equiv.) was prepared in 10 mL of acetonitrile. Subsequently, copper(I) iodide (2.0 equiv.) and triethylamine (3.0 equiv.) were added. The mixture was stirred at room temperature for 3 hours, while the reaction progress was monitored by thin-layer chromatography (TLC). Once the reaction was complete, ethyl acetate (30 mL) was added, followed by a saturated aqueous solution of ammonium chloride (15 mL). The aqueous layer was extracted with ethyl acetate (3 × 30 mL), and the combined organic extracts were washed with brine (20 mL). After drying with anhydrous magnesium sulfate, the solution was filtered and concentrated under reduced pressure. The crude product was purified by flash column chromatography using an n-hexane / ethyl acetate mixture (75:25).The result was the 1H-1,2,3-triazole analogue of β-AKBA (5), obtained as a gummy white solid in 96% yield. Its structure was confirmed by spectroscopic methods, including . 1 H NMR, 13 C NMR and HRMS, which confirmed the molecular formula C42H59N4O5 and a [M+H] + -Peak at 699.44668 (calculated 699.44682) identified

[0028] The synthesis process begins with β-AKBA (1), a natural compound derived from Boswellia sacra gum resin and possessing a free carboxylic acid group at C-24. This compound is coupled with propargylamine (2) using HATU as the coupling agent, yielding intermediate 3 with a high efficiency of 94%. Compound 3 is then reacted with 4-methoxyphenyl azide (4) in the presence of copper iodide (CuI) and triethylamine (Et3N) as the base, using acetonitrile as the solvent. The reaction proceeds at room temperature for 3 hours and leads to the formation of the desired 1H-1,2,3-triazole analogue of β-AKBA (5) in an excellent yield of 96%. EXAMPLE 4: Making a film

[0029] SK-C5-loaded Gelrit gellan gum biopolymer films were prepared using a casting method, with glycerol serving as the plasticizer. A 1% w / v solution was prepared by dissolving 1 gram of Gelrit gellan gum in 100 ml of distilled water at 30°C, ensuring complete homogenization before adding SK-C5. The solution was then divided into two beakers: one containing only Gelrite gellan gum with 0.5% glycerol (GA1 control) and the other containing the plasticizer along with 0.1% SK-C5. After mixing, 20 ml of each formulation was poured into labeled plastic Petri plates (90 × 15 mm) and dried at 25°C for 48 hours. The formed films were carefully peeled off for further analysis. EXAMPLE 5: Characterizations

[0030] Visual analysis of the film samples after peeling revealed a homogeneous and uniform structure across all formulations. The control sample GA1 exhibited a transparent, smooth, and glossy surface, whereas the GA2 film appeared cloudy and opaque due to the addition of SK-C5. In particular, the GA2 films were easier to peel from the Petri plates compared to GA1 and exhibited higher stiffness, flexibility, brittleness, and rigidity. In contrast, GA1 was stickier than GA2, which exhibited better mechanical properties. Furthermore, the incorporation of a binary oil combination into the GA2 film matrix contributed to increased fragility compared to other formulations. Measurement of layer thickness

[0031] The thickness of the developed films was measured using a Deguqmnt caliper with a digital display. Four separate measurements were taken for each film, and the average value was calculated and expressed in millimeters.

[0032] The results show that the thickness of the produced films increased significantly from 0.07 mm to 0.10 mm. The GA1 film sample had a lower thickness of 0.07 mm, while the GA2 film sample had a higher thickness of 0.10 mm. This increase in thickness for the GA2 films can be attributed to the incorporation of the boswellic acid derivative into the polymer film matrix. Mechanical properties

[0033] The tensile properties of the films were evaluated using a texture analyzer equipped with a 10 kg load cell. The tensile test was conducted according to ASTM D882, and the obtained results, including the tensile strength (TS) in megapascals (MPa) and the percentage elongation at break (EAB), were immediately extracted using Exponent Connect software.

[0034] The results show that the GA1 film exhibited a slightly higher tensile strength of 0.03 MPa than the GA2 film, which had a TS of 0.02 MPa. In contrast, GA2 exhibited a slightly higher elongation at break (97.25%) compared to GA1 (95.45%). However, no significant differences in TS or EAB were observed between the control and SK-C5-loaded films, suggesting that the addition of SK-C5 had minimal impact on the mechanical properties. Light transmittance and haze value

[0035] The optical properties of the developed film samples were determined using a YH1200 Haze Meter. Three measurements were taken on different sections of each film sample, and the average value was calculated to evaluate transmittance and haze.

[0036] The haze value of the GA film samples increased significantly from 19.02% for GA1 to 48.24% for GA2. Conversely, the light transmittance decreased, with GA1 exhibiting the highest light transmittance at 92.1%, indicating a more homogeneous and less dense polymer matrix. The GA2 film exhibited a lower transmittance value of 88.14%, suggesting that the addition of the boswellic acid derivative increased light scattering and reduced transparency. Color properties of the films

[0037] The color properties of the films, including brightness (L), green-red (a), and blue-yellow (b), were evaluated using a chroma meter (CR-410). The measurements were conducted to analyze the influence of the SK-C5 admixture on the color properties of the film. ΔE=ΔL2+Δa2+Δb2 ΔL*, Δa* and Ab* represent color differences between the film samples and the standard (L* = 95.9, a* = -0.09, b* = 0.1).

[0038] The color properties of the GA biopolymer films were evaluated based on the L, a*, b*, and ΔE values. The results show that the L value, which represents brightness, was significantly higher for GA1 (1.70) than for GA2 (1.05), indicating lower transparency for GA2 due to the addition of the boswellic acid derivative. The a* value, which indicates the red-green spectrum, was negative for both samples, indicating a red tint; however, GA1 (-0.11) exhibited a slightly higher value than GA2 (-0.12), indicating that GA2 had a more pronounced green tint. The b* value, which represents the yellow-blue dimension, was positive for both GA1 (0.24) and GA2 (0.43) and indicates a bluish hue, with GA2 showing a significantly stronger blue tint due to the boswellic acid derivative.Furthermore, the ΔE value, which measures the overall color change, decreased significantly in GA2 (1.14) compared to GA1 (1.72), indicating a less noticeable color difference in the GA2 films. EXAMPLE 6: Antioxidant Assessment

[0039] The antioxidant potential of the film samples was determined using the ABTS cation scavenging assay. The ability to neutralize ABTS radicals was determined by measuring the absorption shift at 734 nm after a six-minute integration time. For this purpose, 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 a percentage reduction in ABTS cation radicals. where Ac = absorbance of the control solution and At = absorbance of the sample solution.

[0040] The results show that a significant increase in ABTS radical scavenging activity was observed in GA biopolymer films, from 14.46% in GA1 to 33.50% in GA2. The increased antioxidant activity in GA2 is likely due to the presence of the boswellic acid derivative in the film matrix. In contrast, GA1, which lacks this bioactive compound, exhibited lower antioxidant activity, suggesting that Gelrit gellan gum and glycerin alone do not possess strong antioxidant properties. EXAMPLE 7: Water contact angle

[0041] The hydrophobicity of the edible film was evaluated using a contact angle analyzer. A 2 × 2 cm film sample was cut and placed on the sample platform, and a syringe filled with water was positioned for analysis. A drop of distilled water (1.0 µl) was placed on the film surface, and the contact angle was measured in triplicate using dpiMAX software. A high-resolution camera (1044 × 1080) was used to capture images of the water droplet on the film surface for precise measurement.

[0042] The water contact angle (WCA) increased significantly with the incorporation of the boswellic acid derivative into the film matrix, indicating increased hydrophobicity. The GA1 film sample exhibited lower WCA values ​​of 54.81° (left) and 55.95° (right), indicating a more hydrophilic nature that allows water droplets to spread more easily on the surface. This is likely due to the absence of the boswellic acid derivative, as Gelrit gellan gum and glycerin are naturally hydrophilic. In contrast, the GA2 film sample exhibited higher WCA values ​​of 74.3° (left) and 73.18° (right), demonstrating improved water resistance. This increased hydrophobicity of the GA2 films could be beneficial for water-resistant food packaging. Statistical analysis

[0043] Statistical analysis was performed using data from three independent experiments. Means and standard errors were calculated, and a one-way ANOVA was performed to determine significant differences between the means. Duncan's multiple-range test with a significance level of 5% was applied to determine statistically significant differences in the results. Examples

[0044] 1. A biodegradable food packaging composition comprising Gelrit gellan gum composites reinforced with an AKBA derivative (SK-C5), the composition comprising: a) Gelrit gellan gum in an amount of 1% w / v, b) Glycerin in an amount of 0.5% w / v, c) (1-(4-Methoxyphenyl)-1h-1,2,3-triazol-4-yl)methyl)carbamoyl) 3α-acetyloxy-11-oxo-urs-12-en-24-oate (sk-c5) in an amount of 0.1 wt. / vol, d) distilled water in an amount equal to 100%, the composition exhibiting improved mechanical properties, antioxidant activity and hydrophobicity, making it suitable for sustainable packaging applications.

Claims

[1] A biodegradable food packaging composition comprising Gelrit gellan gum composites reinforced with an AKBA derivative (SK-C5), the composition comprising: a) Gelrit gellan gum in an amount of 1% w / v, b) Glycerin in an amount of 0.5% w / v, c) (1-(4-Methoxyphenyl)-1h-1,2,3-triazol-4-yl)methyl)carbamoyl) 3α-acetyloxy-11-oxo-urs-12-en-24-oate (sk-c5) in an amount of 0.1 wt. / vol, d) distilled water in an amount equal to 100%, the composition exhibiting improved mechanical properties, antioxidant activity and hydrophobicity, making it suitable for sustainable packaging applications. [2] The biodegradable food packaging composition according to claim 1, wherein SK-C5 is synthesized from acetyl-11-keto-β-boswellic acid (AKBA) by a propargylamine and azide-alkyne cycloaddition reaction. [3] The biodegradable food packaging composition according to claim 1, wherein the glycerin acts as a plasticizer to improve flexibility, reduce brittleness and increase mechanical strength. [4] The biodegradable food packaging composition according to claim 1, wherein the film is prepared by a casting process and dried at 25°C for 48 hours to achieve a uniform thickness and structure. [5] The biodegradable food packaging composition according to claim 1, wherein the incorporation of SK-C5 increases the hydrophobicity, resulting in a water contact angle between 70° and 75° and making the film suitable for moisture-resistant packaging. [6] The biodegradable food packaging composition according to claim 1, wherein the presence of SK-C5 increases the antioxidant activity of the film, thereby achieving an ABTS radical scavenging activity of up to 33.50%. [7] The biodegradable food packaging composition according to claim 1, wherein the tensile strength of the film is at least 0.02 MPa and the elongation at break is at least 97%, which ensures durability during handling and storage. [8] The biodegradable food packaging composition of claim 1, wherein the film has a haze value of up to 48.24%, thereby reducing transparency while maintaining structural uniformity for improved barrier properties.