Pectin-based Films Research Articles

Design and Evaluation of pH-Sensitive Pectin Films Infused with Anthocyanin-Rich Extracts from Australian Native Fruits for Intelligent Food Packaging Applications

This study investigates the incorporation of anthocyanin-rich extracts from Mountain Pepper Berry (MPB) and Queen Garnet Plum (QGP) into pectin-based films to develop pH-sensitive indicators. Using glycerol as an extraction solvent, significant differences in anthocyanin composition were identified: MPB extracts contained a diverse range of anthocyanin species, with a total content of 267.13 ± 5.21 mg L⁻¹, compared to the predominantly cyanidin-based QGP extracts, with 222.14 ± 1.61 mg L⁻¹. Differences in anthocyanin structures were elucidated using UPLC-Q-ToF-MS/MS analysis. FTIR and UV-Vis spectroscopy were used to assess the compatibility of the extracts with pectin and the homogeneity of anthocyanins within the film structure. Mechanical testing revealed that MPB films exhibited superior tensile strength (8.53 ± 0.51 MPa), stiffness (2274 ± 158.64 gmm− 1), and energy to failure (141.7 ± 16.23 J m− 3) compared to QGP films, which had lower tensile strength (7.74 ± 0.32 MPa), stiffness (1947 ± 125.82 gmm− 1), and energy to failure (115 ± 18.81 J m− 3). Both film types displayed similar moisture content (MPB: 48.89%, QGP: 48.13%) and water vapour permeability, indicating comparable barrier properties. When exposed to volatile ammonia, QGP films showed a more pronounced colour change, attributed to their anthocyanin profile, with a notable shift from red to brown. This research highlights the potential of glycerol-extracted anthocyanins from Australian native fruits as functional additives in pectin films, offering promising applications for intelligent packaging with enhanced mechanical performance and responsive colour-changing properties.Graphical

Enhanced functional pectin films incorporated with olive fruit extracts prepared by deep eutectic solvents

The effect of olive extracts extracted with deep eutectic solvent (DES: choline chloride/glycerol, dl-malic acid/sucrose/glycerol, and citric acid/glycerol, respectively) on the structure, physical properties, and functional activities of pectin films, using DES both as a plasticizer and an extraction medium were explored. The findings revealed the integration of DES as a plasticizer was observed to increase film’s water vapor permeability and elongation at break, while concurrently diminishing its opacity. Furthermore, the incorporation of DES-olive extracts significantly enhanced the tensile strength, moisture barrier property, and opacity of the film, as well as improved its antioxidant and antibacterial activities. The structural analysis indicated the interaction among DES, olive extracts, and pectin facilitated the development of more ordered structures within the films, thereby improving the thermal stability of the pectin-based films. In conclusion, pectin active films using DES as a solvent and plasticizer have the potential to be used to improve antimicrobial and antioxidant packaging materials along with acceptable water resistance.

Multifunctional pectin-based films containing schiff base triggered by pH microenvironment for freshness monitoring and preservation of fresh-cut papayas

Smart packaging materials display prospect to delay the deterioration of fresh agricultural products. In this study, pectin-based composite films were prepared with synthesized Schiff base compounds (GS) by γ-aminobutyric acid (GABA) and syringaldehyde (SA). The scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) showed the cross-linking structures and good compatibility between GS and pectin in the composite films. The films incorporating GS had excellent texture density, water resistance, shielding ability of UV light and partial visible light, as well the ABTS and DPPH radical scavenging activity achieved 90.19% and 85.37%, respectively. The films displayed inhibition of E. coli, S. aureus, and B. cinerea, and were sensitive to color changes with different pH conditions. The GSP films monitored the freshness of fresh-cut papayas with color changes and effectively delayed the ripening of papaya. Therefore, the intelligent and active films triggered by pH microenvironment showed potential application in fruit preservation as packaging materials.

Multifunctional pectin and lignin-containing cellulose nanofiber films with improved UV resistance and mechanical properties

This study aimed to study the real-time interaction of apple pectin and LCNF using Quartz crystal microbalance with dissipation monitoring (QCM-D) to understand the compositional factors that influence their film formation and assess the impact of varying polymer ratios (0–100%) on the UV resistance, hydrophobicity, and mechanical properties of resulting composite films. Results revealed that apple pectin forms partially irreversible interaction with LCNF, evidenced by a frequency change of 14.9 Hz after the final rinsing stage. This finding was supported by FTIR of the composite films, demonstrated by a shift of the broader –OH stretching vibration at 3325 cm−1 to 3302 cm−1 due to the formation of strong hydrogen bonding. LCNF-based films (LCNF >50%) were less soluble in water compared to pectin-based films (pectin >50%) due to less permeable structure and hydrophobic lignin which interferes in hydrogen bonding with water. Pectin-based films displayed high transparency (%Transmittance >89% at 650 nm) and lower hydrophobicity. Due to the presence of lignin chromophores, the UV shielding property was the highest for LCNF-based films as it almost completely shielded the UV spectrum (%T ∼0 at 320 nm). The reinforcement provided by LCNF significantly enhanced the mechanical properties of the films. Consequently, this study offers valuable insights into the real-time interaction dynamics between apple pectin and LCNF, facilitating the development of biocomposite films with versatile properties that hold significant promise for a wide range of applications.

Sustainable pectin-based film for carrying phenolic compounds and essential oil from Citrus sinensis peel waste

Currently, food science faces the challenge of finding methods to deliver functional and nutritional compounds in ready-to-eat products. Biopolymeric films enriched with essential oils are an emerging strategy for incorporating valuable components into edible carrier matrices. This study investigated the wastewater from orange peel hydrodistillation as a source of phenolic compounds and an innovative ingredient to develop bioactive limonene-loaded pectin-based films, addressing waste disposal challenges by developing a multi-functional packaging material. The objective was to evaluate the effects of formulation synergies, particularly pectin-phenolic interactions, on the physicochemical, rheological properties, and essential oil retention capacity of film-forming emulsions, and then assess the effects on the physicochemical and mechanical properties of the films. Films were analyzed for morphology, water vapor permeability, light transmittance, mechanical, chemical, and physical properties, and encapsulation efficiency. Three formulations were evaluated: pectin control (PC), pectin with Tween-80 surfactant (PT), and pectin with phenolic-rich wastewater (PPW). PPW emulsions displayed higher viscosity, consistency, kinetic stability, and essential oil retention compared to PC. The resulting environmentally-friendly films exhibited increased thickness, improved oil droplet distribution, a more crystalline structure, lower clarity, better flexibility, and increased water vapor permeability. Altered FTIR spectrum bands suggested potential pectin-phenolic interactions, influencing film physicochemical properties through mechanisms such as enhanced crosslinking. The PT film-forming emulsion demonstrated lower kinetic stability and less homogeneity than PC and PPW, showing that the use of the commercial surfactant (0.1g/100 g of film-forming emulsion) led to less favorable performance in terms of emulsion stability and film properties compared to PPW and PC. Conclusively, utilizing orange residue for bioactive pectin-based films offers valuable insights for promoting shelf life, reducing the need for formulation surfactants, and adding nutritional value in food applications, while simultaneously repurposing underutilized waste. This research also contributes to insights into the development of more stable emulsions for creating uniform films.

Apple pectin-based active films to preserve oil: Effects of naturally branched phytoglycogen-curcumin host

Pectin has excellent film-forming properties, but its functional properties need to be enhanced. Therefore, we constructed naturally branched phytoglycogen (PG) nanoparticles to solubilize curcumin (CCM) and further enhance the properties of apple pectin-based active films. The size of the PG spherical particles ranged from 30 to 100 nm with some aggregates. The branch density of the PG was 6.02 %. These PG nanoparticles increased the solubility of CCM nearly 1742-fold and a nanosized phytoglycogen-curcumin (PG-CCM) host was formed via hydrogen bonding and hydrophobic interaction. This host promoted the formation of pectin-based films with a dense structure and increased their tensile strength to 23.51 MPa. The coefficient to water vapor permeability, oxygen permeability and carbon dioxide permeability were all decreased indicating their barrier performance were improved. Among them, the oxygen permeability coefficient decreased most, from 1.14 × 10−7 g·m−1·s−1 to 0.8 × 10−7 g·m−1·s−1. Also, the transmittance of the active film at 280 nm and 660 nm decreased to 0.65 % and 72.10 %. Antioxidant and antibacterial properties were significantly enhanced (P < 0.05). And the results showed this film was an excellent oil packaging material. The active film incorporating PG-CCM host can replace heat-sealed plastic bags/pouch made from polyethylene and polypropylene synthetic plastics, and solve the problem that plastic packaging is difficult to degrade and cannot be squeezed clean. This provides a new conceptual framework for developing pectin-based active films by incorporating of PG and CCM.

Advanced pectin-based films: Enhancing antioxidant, antibacterial, UV barrier, and physicochemical properties upon oligomeric limonene derivative incorporation

In the field of active packaging, the utility of limonene (LIM) as an antioxidant, antibacterial agent, and UV blocker has long been recognized. However, its high volatility and limited stability have constrained its full potential. Thus, this research proposes the use of an oligomer derivative, poly (limonene) (PLM), as an alternative functional component in citrus pectin-based films. Percentages of 10% and 20% (w/w of pectin) of PLM and LIM were incorporated leading to films with enhanced antioxidant activity (84% higher than the control sample) and UV light barrier effect (particularly in the UV-A and UV-B range) when 10% of PLM was used. Notably, the introduction of PLM into the films imparted effective antibacterial properties against Staphylococcus aureus. Additionally, it enhanced tensile strength by 35% and elongation at break by 85%. Although the mechanical properties were statistically similar to the films with LIM, its derived oligomer showed superior performance regarding functional properties, probably related to its non-volatility. These findings underscore the potential of PLM as a groundbreaking and non-volatile functional additive for the active packaging field.

Tuning the mechanical properties of pectin films with polyphenol-rich plant extracts

The mechanical properties of pectin films enhanced with polyphenol-rich fruit extracts were investigated. The scavenging and reducing activity of plant extracts incorporated into the pectin films were determined using bench assays, and their antioxidant activity was correlated with a high presence of polyphenols, which were predominantly comprised of flavonoids and anthocyanins. The pectin films generated from the extracts exhibited a range of mechanical properties; tensile strength (4.99 MPa – 6.91 MPa), elongation at break (45.8 % - 52.3 %), and stiffness (1835 g mm−1 - 2765 g mm−1). To investigate the underlying relationships between plant extract composition and mechanical properties, Projection to Latent Structures (PLS) models were developed. The PLS models revealed that extracts containing high sugar and polyphenol content increase the tensile strength and moisture content of films. The elongation at break of the films was improved or diminished depending on the profile of sugar, acids, and polyphenols in the fruit extracts. Furthermore, the structures and concentration of anthocyanins and flavonoids were identified to strongly influenced the elongation at break differences. By modifying the concentration of sugars, organic acids, and polyphenols, the mechanical properties of pectin-based films can be tuned for tailored applications as food packaging materials.

Development of pH-responsive intelligent and active films based on pectin incorporating Schiff base (Phenylalanine/syringaldehyde) for monitoring and preservation of fruits

This study aimed to develop pectin-based films by incorporating Schiff base compounds (SPS) synthesized by phenylalanine and syringaldehyde. The SEM images showed good compatibility between SPS and pectin matrix. The interaction of SPS and pectin matrix was analyzed by FTIR and XRD. Results indicated that the cross-linking effects between SPS and pectin matrix improved the thermal stability, water resistance and light shielding ability of the films. The incorporation of SPS in the films scavenged more than 80% of DPPH and ABTS free radicals, exhibited sustained antimicrobial ability against S. aureus, E. coli and B. cinerea, and showed significant color changes as pH-responsive films. Especially, the intelligent active coating/films inhibited the quality deterioration of cherry tomatoes and fresh-cut mangoes, and monitored the freshness of fresh-cut mangoes during storage. Therefore, the SPS/PE films have a potential application in maintaining fruit quality and monitoring the freshness of fresh-cut fruit.

Film Properties of Pectin Obtained from Various Fruits’ (Lemon, Pomelo, Pitaya) Peels

Food by-products, as sources of high-value compounds, have shown great promise for formulating novel food packaging and edible films for food preservation. This work focused on extracting pectin from lemon, pomelo, and pitaya peels using an ethanol precipitation method. The degree of esterification and the monosaccharide composition of the extracted pectin were determined, and the antioxidant activity of the pectin was assessed. Subsequently, pectin-based films were prepared using the casting method, employing pectin from various sources. These films’ physical and mechanical properties (tensile strength and elongation at break) were assessed, and their microstructure and intermolecular interactions were examined using scanning electron microscopy and Fourier transform infrared spectroscopy analysis. The results of this study demonstrate variations in the degree of esterification among the three pectin samples, with pomelo peel and lemon peel pectins exhibiting higher degrees of methylation compared to pectin from pitaya peel, which had a lower degree of methylation. However, no significant differences were observed regarding the films’ moisture content and water vapor permeability. Notably, the films made from pitaya peel pectin exhibited superior tensile strength and elongation at break to those derived from pomelo peel and lemon peel pectins. The pectin recovered from these fruit peels had great film properties and thus could be utilized for food packaging and edible films.

Characterization of antifungal citrus pectin-based films for potential agricultural application

In this study, pectin-based films blended with alginate and crosslinked with copper ions for potential application in agriculture were investigated. Copper was selected as crosslinking agent, due to its key role as a plant micronutrient, antifungal ability, and focal activity in the pectin crosslinking process. FTIR analysis confirmed the interactions between pectin, alginate and copper salt. The inclusion of alginate in film improved the binding activity of copper ions, providing denser 3d network with enhanced physical-chemical properties. The crosslinked film containing 60 wt% of pectin and 40 wt% of alginate had the highest tensile strength (59.8 MPa), highest UV barrier (transmission of light=0%), and the lowest swelling degree (121%) and water vapor permeability (0.320 ng/ m s Pa). Moreover, the release of copper ions from this formulation after 28 days of immersion in water and soil was 9 and 13 ppm, respectively. The biodegradation rate after 28 days of exposure in the soil was 54%. Nevertheless, all crosslinked pectin-alginate films inhibited the growth of the Fusarium and Aspergillus phytopathogens and demonstrated non-phytotoxicity on germination and growth of wheat. Hence, the system developed in this work can potentially be used as novel, bio-active, tunable plant protective biodegradable foliar spray in agriculture sector.

Edible coatings based on plant components for active packaging of fresh/fresh-cut fruits

Edible coatings based on plant components – citrus pectin and oregano essential oil were developed for an active fresh/fresh-cut fruits packaging. Films having relatively homogeneous microstructures were prepared with variations in porosity depending on oil concentration. The increase in oil content did not reduce the water vapor permeability of films, but the water contact angle indicated a greater hydrophobicity of the film's surface with the addition of 0.5% and 1% essential oil. The antioxidant activity of pectin-based films significantly increased with increasing in oil content, while films with 0.5% and 1% oil showed great inhibition against all tested bacterial and fungal strains. Fresh-cut apples coated with pectin-oil formulations remained fresher compared to the uncoated ones during storage. The slices with coatings containing 0.05% and 0.1% oregano oil showed the best retention of freshness and color. Results indicated great potential of coatings based on pectin and oregano oil as components from plants to be used as an edible active packaging material for fresh/fresh-cut fruits.

Characterization of ionically crosslinked mango peel pectin-based films: Effect of different cations on the improved properties of film

Mango peels are often dumped as waste, producing severe environmental issues. This study investigated the physicochemical properties of mango peel pectin and its based films prepared by crosslinking with cations. The results showed that pectin obtained from mango peel is high-methoxy pectin and consists of aggregates of linear homogalacturonan. Thin films were prepared with the extracted mango peel pectin crosslinked with Ca2+, Zn2+, and Cu2+, respectively, and were characterized. The crosslinking improved the properties of the pectin-based film, including tensile strength, hydrophobic properties, and thermal stability. Fourier transform infrared spectroscopy techniques and X-ray diffraction exhibited the nature of inter-molecular interactions between ions and pectin in films, while scanning electron microscope showed the observable differences in the microstructure. These results showed that the crosslinking of pectin with cations would provide new insight for preparing a pectin-based film with excellent properties.

Pectin-nanolignin composite films with water resistance, UV resistance, and antibacterial activity

In this work, pectin-lignin nanoparticle (LNP) composite films were prepared, the physical, antioxidant and antibacterial properties of the films systematically evaluated. The LNP were compatible with the pectin matrix, and the tensile strength (TS) and water contact angle (WCA) of the pectin-based films were enhanced by 164% and 56% at the optimum LNP loading of 3.0% (w/w). The results of dynamic WCA demonstrate the hydrophobic stability of pectin-LNP composite films. Even trace amounts of LNP (1.0%, w/w) were found to significantly improve the mechanical properties (TS improved 67.33%), hydrophobicity (WCA improved 48.83), and water barrier properties (the water vapor permeability decreased by 25.30%) of the pectin-based films. The tight entanglement and strong positive interaction between pectin and LNP promote the formation of dense structures, which is beneficial to the film properties. In addition, all pectin-LNP composite films almost completely shield the UVB (320-275 nm) and UVC (275-200 nm) spectrum, along with most of the UVA (400–320 nm) spectrum, which demonstrates their strong anti-ultraviolet performance. In terms of bioactivity, the addition of LNP significantly enhanced the DPPH radical scavenging ability (maximum boost is 6.33 times) and antibacterial ability (maximum inhibition rate was 78.79 for S.aureus and 47.80% for E.coli) of the pectin film. These results suggest that the pectin-LNP composite film are promising active packaging materials for food preservation/packaging applications.

Recent progress in pectin extraction and their applications in developing films and coatings for sustainable food packaging: A review

Perishable foods like fruits and vegetables, meat, fish, and dairy products have short shelf-life that causes significant postharvest losses, which poses a major challenge for food supply chains. Biopolymers have been extensively studied as sustainable alternatives to synthetic plastics, and pectin is one such biopolymer that has been used for packaging and preservation of foods. Pectin is obtained from abundantly available low-cost sources such as agricultural or food processing wastes and by products. This review is a complete account of pectin extraction from agro-wastes, development of pectin-based composite films and coatings, their characterizations, and their applications in food packaging and preservation. Compared to conventional chemical extraction, supercritical water, ultrasound, and microwave assisted extractions are a few examples of modern and more efficient pectin extraction processes that generate almost no hazardous effluents, and thus, such extraction techniques are more environment friendly. Pectin-based films and coatings can be functionalized with natural active agents such as essential oils and other phytochemicals to improve their moisture barrier, antimicrobial and antioxidant properties. Application of pectin-based active films and coatings effectively improved shelf-life of fresh cut-fruits, vegetables, meat, fish, poultry, milk, and other food perishable products.

Pectin-based films with thyme essential oil: production, characterization, antimicrobial activity, and biodegradability

Pectin-based films with thyme essential oil: production, characterization, antimicrobial activity, and biodegradability

Fabrication, characterization and biological properties of pectin and/or chitosan-based films incorporated with noni (Morinda citrifolia) fruit extract

Noni ( Morinda citrifolia ) fruit is a natural food source rich in antioxidant and antimicrobial compounds. In this study, the phytochemicals of noni fruit extract (NFE) were identified by using HPLC-ESI-qTOF/MS method. Subsequently, casting method was adopted to prepare pectin and/or chitosan (CH)-based films incorporated with NFE. The influence of NFE addition on the physicochemical, microstructure, and biological properties of pectin and/or CH-based films was evaluated. Results confirmed that incorporation of NFE into pectin and/or CH-based films increased the tensile properties, water vapor permeability (WVP) and opacity of the films, but declined the thickness, moisture content and water solubility slightly. However, pectin-based films showed higher water solubility than CH-based films followed by pectin/CH-based films. In addition, the addition of NFE slightly decreased the film's thermal stability, and CH-based films showed better thermal stability compared to pectin or pectin/CH-based films. Regardless of the NFE addition, no significant morphological changes of pectin and pectin/CH-based films were observed using scanning electron microscopy (SEM). Compared with the control films, the average roughness of CH-based film surface was evidently increased. FTIR results showed that the addition of NFE had no remarkably influences on chemical structures of the films. More importantly, the addition of NFE effectively improved the antioxidant and antibacterial activities of the pectin and/or CH-based films, which was due to phenolic compounds existed in NFE. In short, pectin and/or CH-based films incorporated with NFE is characterized with eco-friendliness, reliability and multiplex bio-activities, which is expected to be a promising alternative for the plastics food packaging film. • Phenolic compositions of noni fruit extract (NFE) were identified by LC-MS/MS. • Pectin and/or chitosan-based edible films incorporated with NFE were fabricated. • Physicochemical properties of the prepared films were investigated and compared. • Incorporated with NFE improved the tensile strength and opacity of the films. • Incorporated with NFE slightly decreased the film's thermal stability. • Incorporated with NFE enhanced antioxidant and antibacterial activities of the films.

Novel pectin-based nanocomposite film for active food packaging applications

Novel pectin-based films reinforced with crystalline nanocellulose (CNC) and activated with zinc oxide nanoparticles (ZnO NPs) were prepared by solvent-casting method. Film ingredients enhanced UV-blocking, thermal, and antibacterial properties of active films against well-known foodborne pathogens. Optimal active films exhibited higher mechanical, water vapor barrier properties compared to pristine pectin films. SEM confirmed the even distribution of CNC and ZnO NPs in pectin matrix and their interactions were proven using FTIR. Wrapping hard cheese samples artificially contaminated with Staphylococcus aureus and Salmonella enterica with the ternary nanocomposite film at 7 °C for 5 days significantly reduced the total population counts by at least 1.02 log CFU/g. Zn2+ migrating to wrapped cheese samples was below the specific limit (5 mg/kg), confirming their safety for food contact. Overall, ZnO/CNC/pectin nanocomposite films represent promising candidates for active food packaging as safe, eco-friendly alternatives for synthetic packaging materials.

Sustainable bioactive pectin-based films to improve fruit safety via a circular economy approach

This work reports on the valorisation of persimmon (Diospyros kaki Thunb.) for the development of food-grade antiviral coatings against major viral foodborne pathogens, human noroviruses (NoVs) and hepatitis A virus (HAV). Initially, the antiviral activity of polyphenol-rich pectin extracts with abundant non-covalent interactions (PPN), pectin extracts enriched with intact pectin-polyphenol ester and O-glycosyl bonds (PPC) and hydro-ethanolic polyphenol-rich extracts (EPE) was compared. Higher viral reductions were found for the pectin extracts rich in polyphenols, mainly in those containing covalent pectin-polyphenol interactions. This specific extract was mixed with commercial citrus pectin (CP) to develop active edible films. Dry films were analysed in terms of their optical, morphological, mechanical and barrier properties. Addition of the bioactive pectin persimmon extract resulted in more coloured films with lower transparency. The presence of covalently-linked polyphenols gave rise to stiffer films, with lower sorption capacity and more hydrophobic nature. The infectivity of MNV and HAV on fresh blueberries after the coating treatments was reduced by approximately 4.28 and 2.38 log, respectively, after overnight incubation, as compared to the controls, when 10% PPC was incorporated into the film. Higher amounts of PPC did not significantly improve the antiviral activity and a complete inactivation for both viruses was observed after 4 days of storage at 25 °C. This paper highlights the potential of persimmon discards as a cheap source of food-grade antiviral coatings with improved physicochemical properties as compared to commercial citrus pectin.

Properties of pectin-based films from white-fleshed pitaya (Hylocereus undatus) peel waste as affected by montmorillonite

In this study, pectin was prepared from white-fleshed pitaya (Hylocereus undatus) peel waste to develop a novel biodegradable film, and the reinforcement effect of montmorillonite (MMT) on the films was investigated. The presence of MMT could lower the moisture sensitivity, which was reflected in the lowered moisture uptake capacity and water vapor permeability. The incorporation of MMT into the white-fleshed pitaya (Hylocereus undatus) peel pectin (WPPP) film improved the light-barrier property of WPPP films with the transmittance of ultraviolet and visible light reduced. The WPPP/MMT composite film might have a more compact structure and lower chain mobility, resulting in the improved tensile strength and decreased elongation at break when the content of MMT was 1–5 wt%. In addition, WPPP/MMT composite films demonstrated a higher thermal stability compared with the plain WPPP films. It was found that approximately 90% of the WPPP and WPPP/MMT films were degraded on the 15th days, suggesting their great biodegradability. The present study might demonstrate that pitaya peel waste pectin could become a novel film-forming polymer for edible or packaging films, and the incorporation of MMT was effective in improving the overall performance of films, as reflected by the enhanced tensile strength, thermal stability, and barrier properties to water vapor and ultraviolet as well as visible light, which might assist in the sustainable valorization of pitaya by-products.