A functional polysaccharide film forming by pectin, chitosan, and tea polyphenols

Effect of different zein/tea polyphenol/apple pectin coating on nutritional, physicochemical properties of fresh walnut kernel preservation

In this study, zein/apple pectin/tea polyphenol layer-by-layer assembled cling film prepared by solution casting was characterized, and the preservation effect of composite coatings, double, triple, and quadruple multilayer layer-by-layer assembly coatings on fresh walnut kernels at 4 °C was evaluated. As the number of assembly layers increased, the water vapor barrier increased, and the lower the film's UV transmittance. The assembled film's antioxidant and antibacterial activities were significantly higher than composite film. The moisture, color, and texture of the fresh walnut kernels treated with the assembled coatings were less different from 0 d fresh walnut kernels after 40 d of storage at 4 °C. The acid value, peroxide value, and total number of bacterial colonies of the fresh walnut kernels with 4-layer assembled coatings were significantly lower than those of the composite coatings. Overall, zein/apple pectin/tea polyphenol layer-by-layer assembled coating is an effective way to the fresh walnut kernel preservation.

Pectin-Cellulose Nanofiber Composites: Biodegradable Materials for Modified Atmosphere Packaging

Pectin blended with cellulose nanofiber (CNF) sourced from wood pulp has excellent potential for modified atmosphere packaging (MAP), as demonstrated with refrigerated or sliced fruits enclosed in parchment coated with pectin-CNF composites. Addition of sodium borate (NaB) augments the antioxidant capacity of the composite, most likely through the generation of unsaturated pectic acid units. Packaging materials coated with pectin-CNF-NaB composites demonstrate better humidity regulation in refrigerated spaces over a 3-week period relative to uncoated controls (50% less variation), with improved preservation of strawberries as well as a reduction in the oxidative browning of sliced apples. Pectin-CNF films are both biorenewable and biodegradable as confirmed by their extensive decomposition in soil over several weeks, establishing their potential as a sustainable MAP material. Lastly, self-standing films are mechanically robust at 80% RH with tensile strength and toughness as high as 150 MPa and 8.5 MJ/m2 respectively. These values are on par with other bioplastic composites and support the practical utility of pectin-CNF composites in functional packaging applications.

Nacre-like structural carboxymethyl cellulose dual-layered film with a combination of high strength, elongation, and UV-blocking for food packaging

Carboxymethyl cellulose (CMC) holds great potential for food preservation applications, provided its mechanical properties and UV-blocking performance are significantly enhanced. Considering this, the study focuses on developing a novel dual-layered film using the layer-by-layer casting method. The resulting film exhibits a compact dual-layered structure, with a nacre-like upper layer (chitosan/montmorillonite/tea polyphenols) and a dense bottom layer (CMC/sodium alginate/nano-hydroxyapatite/tea polyphenols). This design enhances tensile strength through hydrogen bonding interactions among nanoparticles, active substances, and polymers, while the nacre-like and layered structures contribute to improve elongation. Furthermore, the incorporation of tea polyphenols significantly enhances the UV-blocking performance of the film. Compared to the single-layer film, the dual-layered film exhibits improved tensile strength (from 45.19 MPa to 63.58 MPa), elongation (from 52.56 % to 82.45 %), and UV-blocking capability (from 99 % to 100 %). Additionally, the dual-layered film presents excellent water resistance (moisture content: 13.64 %, water solubility: 6.26 %), oxygen permeability (1.841 × 10-3 g/m2 s) and antioxidant activity (scavenging capability for DPPH: 67.25 %). When employed as packaging film, the dual-layered film effectively reduces tomatoes weight loss from 9.04 % to 7.52 % and extends shelf life. This study offers an innovative approach to promote the development of CMC for food preservation applications.

Preparation of polysaccharide-based films synergistically reinforced by tea polyphenols and graphene oxide

In this study, pectin (PE) composite films containing tea polyphenol (TP) and graphene oxide (GO) were developed. The effects of TP and GO on the appearance, structure, mechanical properties, barrier properties, hydrophobicity, and antioxidant properties of pure PE films were investigated. The results demonstrated that the addition of 1 % w/w TP and 1 % w/w GO increased the tensile strength (TS) and elongation at break (EB) of the composite films to 20.22 MPa and 34.18 %, respectively. Additionally, the water vapor permeability (WVP) was reduced to 0.67 ± 0.17 (×10-10 g-1s-1Pa-1), and both the moisture content and water contact angle were significantly decreased. Furthermore, the incorporation of TP enhanced the antioxidant properties of the composite films and demonstrated the slow-release capability of TP. Blueberry fruits packaged in PE-TP-GO film maintained an optimal appearance after eight days of storage at 25 °C, with a reduction in shrinkage index of approximately 29.4 % compared to those packaged in the PE film.

Emerging chitosan systems incorporated with polyphenols: Their applications in intelligent packaging, active packaging, and nutraceutical systems - A comprehensive review

Chitosan, a biodegradable anionic polysaccharide, has been increasingly investigated for food packaging and nutraceutical applications. In recent years, chitosan has been combined with polyphenols, a group of health promoting bioactive compounds, to enhance their physicochemical, functional, and biological properties. The synergistic functional attributes of chitosan and polyphenols have led to the development of several novel food packaging materials and nutraceuticals. Despite, several investigations being conducted on chitosan-polyphenol materials (e.g., films, coating, nanoparticles, complexes, emulsion gels), currently there is a lack of studies that comprehensively evaluate the combined effect of chitosan and polyphenol in development of both food packaging materials and nutraceuticals. Therefore, in this review, novel packaging materials and nutraceuticals developed employing chitosan-polyphenol in recent years (2018-2024) are thoroughly investigated. This review initiates with the source, production strategies, and techniques employed to improve the functionality of chitosan. Secondly, the findings associated with important intelligent packaging materials, including pH indicator, time-temperature indicator, and freshness indicator, developed using chitosan-polyphenol is investigated. Following that, the applications of chitosan-polyphenol materials in active food packaging (i.e., antimicrobial, antioxidant, oxygen scavenger, ethylene scavenger, and moisture scavenger) are explored. Notably, chitosan-based delivery systems that are employed to improve the chemical stability, bioaccessibility, and biological properties of polyphenols for nutraceutical applications are summarized. Finally, the challenges associated with the industrial application of chitosan-polyphenol materials are addressed. Overall, this review would benefit a wide range of scientists from food packaging to ingredient sectors by providing the current knowledge associated with chitosan-polyphenol materials.

Pectin/Gellan Gum Hydrogels Loaded with Crocus sativus Tepal Extract for In Situ Modulation of Pro-Inflammatory Pathways Affecting Wound Healing

Tepals of the Crocus sativus flower constitute the most abundant floral residue during saffron production (350 kg tepals/kg stigmas). Being a natural source of polyphenols with antioxidant properties, they can be reused to create potentially valuable products for pharmaceutical applications, generating a new income source while reducing agricultural bio-waste. In this work, composite hydrogels based on blends of pectin and gellan gum containing Crocus sativus tepal extract (CSE) have been proposed for the regeneration and healing of cutaneous wounds, exploiting the antioxidant properties of CSE. Various physico-chemical and mechanical characterizations were performed. The skin permeation of CSE was investigated using Franz cell diffusion system. The composite films were cytocompatible and able to counteract the increase in ROS, restore the production of matrix proteins, and favor wound closure. To conclude, CSE-loaded composite films represent a promising strategy to promote the body's natural healing process. In addition, by reusing saffron tepals, not only can we develop new, sustainable treatments for skin diseases, but we can also reduce agricultural waste.

Investigation of the interaction mechanism of citrus pectin-polyphenol-protein complex

Citrus pectin is an anionic polysaccharide in citrus, which may improve the stability of citrus juices. This study investigated the influence of citrus pectin on the stability of protein-polyphenol complexes in the citrus juice model system and its interaction mechanism by multispectral and molecular dynamics (MD) simulations. Dynamic light scattering (DLS) and differential scanning calorimetry (DSC) showed that the citrus pectin-proanthocyanidin-zein complex improved the model citrus juices' cloud and thermal stability. Molecular dynamics (MD) simulations suggested that both pectin and proanthocyanidin bound to the U-shaped cavity of the zein molecules. Electrostatic and van der Waals forces were predominant in citrus pectin-zein. In contrast, van der Waals forces predominantly drove in proanthocyanidin-zein. This study indicated that citrus pectin could stabilize juice by delaying the onset of protein-polyphenol haze formation, which may provide new strategies for improving the quality, stability, and nutritional profile of fruit juice systems.

A dual-drive strategy for enhanced protein crystallization with sodium alginate/hyaluronic acid film: Protein adsorption and supersaturation regulation

Protein crystallization is essential for determining the three-dimensional structures of biomacromolecules and advancing biopharmaceutical development, yet it remains a major challenge in structural biology due to common issues like slow nucleation rates and inconsistent crystal quality. Herein, a dual-drive crystallization (DDC) strategy, relying on a composite film of sodium alginate (SA) and hyaluronic acid (HA), is reported to synergistically regulate both protein adsorption and solution supersaturation. Driven by the electrostatic interactions of SA and the water absorption properties of HA, the SA/HA film achieves enhanced crystallization efficiency and controlled crystal quality mainly. It significantly reduces lysozyme nucleation time by over 66.0 % and better controls crystal size distribution. Molecular simulations further reveal a strong electrostatic interaction energy of -17.0 kcal·mol-1 between protein and SA, which enhances protein adsorption and then promotes cluster formation, nucleation, and crystal growth. Additionally, the DDC strategy efficiently promotes the crystallization of both thaumatin and proteinase K, enhancing the crystallization success rate for proteins with opposite charges. These results highlight the advantages and promising potential of SA/HA film-assisted protein crystallization for effectively producing protein crystals suitable for diverse applications.

Polysaccharide-Based Packaging Coatings and Films with Phenolic Compounds in Preservation of Fruits and Vegetables-A Review

Considerable interest has emerged in developing biodegradable food packaging materials derived from polysaccharides. Phenolic compounds serve as natural bioactive substances with a range of functional properties. Various phenolic compounds have been incorporated into polysaccharide-based films and coatings for food packaging, thereby enhancing product shelf life by mitigating quality degradation due to oxidation and microbial growth. This review offers a comprehensive overview of the current state of polysaccharide-based active films and coatings enriched with phenolic compounds for preserving fruits and vegetables. The different approaches for the addition of phenols to polysaccharides-based packaging materials are discussed. The modifications in film properties resulting from incorporating polyphenols are systematically characterized. Then, the application of these composite materials as protectants and intelligent packaging in fruit and vegetables preservation is highlighted. In future, several points, such as the preservative mechanism, safety evaluation, and combination with other techniques along the whole supply chain could be considered to design polyphenol-polysaccharides packaging more in line with actual production needs.

Fabrication of antimicrobial packaging based on polyaminopropyl biguanide incorporated pectin/polyvinyl alcohol films for fruit preservation

Pectin (PEC)/polyvinyl alcohol (PVA), plasticizers, and polyaminopropyl biguanide (Pb) (0.125%-1%) were used to prepare the film solution. The results demonstrated significantly enhanced tensile strength and elongation at break of PEC/PVA/Pb 0.25% film than PEC/PVA film. Scanning electron microscopy was carried out to investigate the continuous and dense structure of the PEC/PVA/ Pb0.25% film. FTIR, XPS, and XRD revealed that Pb addition to the PEC/PVA film matrix changed its physicochemical properties by forming new hydrogen and CN bonds. Moreover, the composite films exhibited strong antimicrobial activity against food-borne microorganisms (E. coli and S. aureus), and post-harvest pathogens (P. italicum and F. proliferatum) in vitro. The composite film effectively inhibited P. italicum growth during citrus experiments, while maintaining nutritional components (vitamin C, total flavonoid, and total polyphenol content). Overall, the antimicrobial composite film presented promising applicability in food packaging.

A comprehensive review of chitosan-based functional materials: From history to specific applications

Chitosan (CTS), a natural biopolymer derived from chitin, has garnered significant attention owing to its potential chemical, biological, and physical properties, such as biocompatibility, bioactivity, and biosafety. This comprehensive review traces the historical development of CTS-based materials and delves into their specific applications across various fields. The study highlights the evolution of CTS from its initial discovery to its current state, emphasizing key milestones and technological advancements that have expanded its utility. Despite the extensive research, the synthesis and functionalization of CTS to achieve desired properties for targeted applications remain a challenge. This review addresses current problems such as the scalability of production, consistency in quality, and the environmental impact of extraction and modification processes. Additionally, it explores the novel applications of CTS-based materials in biomedicine, agriculture, environmental protection, and food industry, showcasing innovative solutions and future potentials. By providing a detailed analysis of the current state of CTS research and identifying gaps in knowledge, this review offers a valuable resource for researchers and industry professionals. The novelty of this work lies in its holistic approach, combining historical context with a forward-looking perspective on emerging trends and potential breakthroughs in the field of CTS-based functional materials. Therefore, this review will be helpful for readers by summarizing recent advances and discussing prospects in CTS-based functional materials.

Development of antioxidant arabinoxylan-tea polyphenol composite films for enhanced preservation of fresh grapes

In this study, arabinoxylan (AX) was used as a substrate, and tea polyphenol (TP) as a functional additive to create degradable, non-polluting, and antioxidant packaging materials. The effects of different TP concentrations on light transmittance and antioxidant activity of the AX-TP composite films were analyzed. The colors of the films gradually deepened with increasing TP content. The maximum scavenging rate of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals using the AX-TP composite film solution of 59.13 ± 2.19 % was achieved at the TP concentration of 2.0 %. AX-TP composite films with different TP concentrations were applied to the surfaces of grapes, and the sensory quality, shriveling and decay rates, titratable acid, and weight loss rate of grapes during storage were evaluated using data from different experimental groups. The AX-TP composite films coated on grapes reduced the transpiration of water in the fruit and delayed grape spoilage, demonstrating an excellent preservation effect. These results show that AX-TP composite films increase the shelf life of fresh grapes.

Preparation, structural characterization, and antioxidant activity of polysaccharide chitosan films from Porphyra haitanensis

Porphyra haitanensis polysaccharide-chitosan (PHP-CS) films were prepared by combining PHP and CS used the casting method with CaCl2; the structure, and physical and chemical properties of the film were studied by rheometry, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), light transmittance, scanning electron microscopy (SEM) and other means. The results indicated that the tensile strength of the PHP-CS film after formation was 5.63 ± 0.11 MPa, which was due to the interaction between the negative group in PHP and the positive group of CS under the action of hydrogen bonding and van der Waals forces. XRD and SEM results showed that there was a crystal structure in PHP-CS films, which was due to the combination of sulfuric acid group, amino group of CS and CaCl2 in PHP. Importantly, PHP-CS films had strong UV-blocking properties and high thermal stability. In addition, PHP-CS films had stronger oxidation resistance than PHP and CS. Therefore, PHP-CS film has wide application potential in food preservation and packaging.

Development of apple pectin/chitosan-based active films integrated with apple polyphenol/hydroxypropyl-β-cyclodextrin inclusion complex for pork preservation

Sustainable bio-based active films are promising alternative materials that can alleviate the growing environmental problems. Apple processing generates a large number of by-products rich in pectin and polyphenols. Herein, we extracted apple pectin (Apec) from apple pomace, developed a multifunctional bilayer film based on Apec and chitosan by incorporating inclusion complex of apple polyphenol and hydroxypropyl-β-cyclodextrin (ICAH). The results showed that the incorporation of ICAH remarkably improved the mechanical strength, barrier properties, and the thermal stability of the films. Meanwhile, the composite films loaded with ICAH exhibited potent antioxidant and antibacterial activities in vitro. Furthermore, a 7-day shelf-life analysis on fresh pork verified that the films were effective in maintaining the pH level (below 6.0), reducing the thiobarbituric acid reactive substance (from 1.18 to 0.63 mg MDA/kg) and total volatile basic nitrogen (from 23.27 to 14.03 mg/100 g), and inhibiting the microbial growth (from 6.83 to 3.74 log CFU/g), thereby obtaining a satisfactory sensory evaluation. The pork wrapped with the films can significantly extend the period of freshness from 4 days to 7 days under refrigeration at 4 °C. The results suggest that the prepared composite films hold promise as an active packaging material for application in pork preservation.

Properties of Guar Gum/Pullulan/Loquat Leaf Extract Green Composite Packaging in Enhancing the Preservation of Chinese Water Chestnut Fresh-Cut Fruit

Loquat leaf extract (LLE) was added to guar gum and pullulan as an environmentally friendly packaging film (GPE) to preserve Chinese water chestnuts (CWCs). The effect of the amount of LLE on the guar gum/pullulan composite film was investigated. The optimal amount of LLE was 4% (GPE4), with lower water vapor permeability (WVP) and greater mechanical strength, antioxidant, and comparable antibacterial performance than many pullulan-based films. Upon packing the CWCs for 4 days, the weight loss rate of GPE4 was only 1.80 ± 0.05%. For GPE4, the POD activity, the soluble solid content, and the vitamin C (Vc) content of the CWCs were 21.61%, 36.16%, and 26.22% higher than those of the control sample, respectively. More importantly, GPE4 was effective in preserving the quality of CWCs after 4 days of storage, better or at least comparable to non-biodegradable plastic wrapping (PE). Therefore, it can be concluded that GPE films hold significant promise as a sustainable alternative packaging material for preserving fruit-based foods like CWCs, potentially replacing PE in the future.

A water-resistant egg white/chitosan/pectin blending film with spherical-linear molecular interpenetrating network strengthened by multifunctional tannin-nisin nanoparticles

Edible films are effective alternatives to plastic packaging, however, the hydrophilicity of edible films based on protein and polysaccharide limits the application. Therefore, we fabricated a water-stable hybrid film with a linear-spherical interpenetrating molecular topology network using egg white (EW), chitosan (CS), and pectin. Meanwhile, the nisin-tannin acid self-assembly complex nanoparticles were employed as a multifunctional cross-linker, antibacterial and antioxidant agent to improve the performance of films. The FTIR, XRD, and SEM analysis revealed that the conformation and crystalline structure rearrangement of chitosan induced by the alkaline environment provided by egg white enhanced the network structure of films, effectively avoided the addition of modifying reagents. The proposed hybrid films exhibited excellent properties, with EW/TNPCS3 showing the best overall performance. The water contact angle (WCA) increased to 105.27 ± 1.62°, and its dissolution and swelling rates were significantly lower than pure egg white and pure chitosan films. Moreover, tannin-nisin (TN) nanoparticles endowed the films with excellent antimicrobial activity against the common Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Thus, the prepared blending films have great application potential in food preservation, especially to maintain stable performance in high humidity environment.

Chitosan-casein blended with condensed tannin and carnauba wax for the fabrication of antibacterial and antioxidant food packing films

In this study, various chitosan-based films such as chitosan (C), chitosan-condensed tannin (CT), chitosan-casein (CC), and chitosan-casein-condensed tannin (CCT) films were prepared for the purpose of food packaging. In order to improve the hydrophobicity of these films, carnauba wax was blended into CCT to produce CCTW film. Properties such as morphology, UV resistance, water solubility, barrier performance, tensile strength, antioxidant, antibacterial and its performance as food packaging were evaluated. Compared with other chitosan-based films, CCTW films exhibited higher UV resistance, tensile strength, thermal stability and hydrophobicity. The addition of both condensed tannin and carnauba wax has significantly decreased the water vapor and oxygen permeability of the CCTW films. The CCTW films were proved capable of repelling most daily consuming liquids. Besides, CCTW films displayed outstanding free radical scavenging rate and antibacterial properties. Meanwhile, bananas wrapped with CCTW films remained fresh for seven days without any mold growth and outperformed other types of films. Apart from that, the CCTW films also showed biodegradable characteristics after exposure to Penicillium sp. These distinguished characteristics made the CCTW films a promising packaging material for long-term food storage.

Eco-friendly biodegradable film based on kombucha mushroom/corn starch/parsley extract: Physicochemical and antioxidant/antibacterial properties

The main purpose of this study was to produce biodegradable film based on kombucha mushroom (KM), so kombucha mushroom was grown and used to prepare biodegradable film. Glycerol (Gl), corn starch (St), and parsley extract (PE) were used to improve the characteristics of the kombucha mushroom-based film. The physicochemical, thermal, and antibacterial properties of the films were investigated using different techniques. The obtained results showed that starch significantly increased the tensile strength of the film (3 Mpa) and glycerol improved the flexibility of the film (70%). Starch increased the film's resistance to dissolution in water, and parsley extract and starch improved water vapor permeability. The pure film of kombucha mushroom had good antioxidant (40% ± 2%) and antibacterial properties, and parsley extract significantly increased these properties of the film, so that the prepared film can be considered as an active film. Starch had no significant effect on antioxidant and antibacterial properties. The pure kombucha mushroom film had cracks on the surface, and the addition of starch removed these cracks and made the structure of the film more homogeneous. Electrostatic interactions between kombucha mushroom, glycerol, starch, and parsley extract were confirmed by Fourier transform infrared spectroscopy (FTIR) results. The pure film of kombucha mushroom was a completely amorphous film, which glycerol, parsley extract, and starch improved the crystallinity of the film. Glycerol and parsley extract decreased the thermal resistance of the film, but starch increased this property significantly (about 40°C), so that the kombucha mushroom/glycerol/starch/parsley extract composite film had the highest thermal resistance. In addition to having acceptable mechanical, thermal, and structural properties, the film based on kombucha mushroom can be used as an active film in the packaging of food products sensitive to microbial and oxidative spoilage due to having suitable antioxidant and antimicrobial properties.

Research progress on natural preservatives of meat and meat products: classifications, mechanisms and applications

Meat and meat products are highly susceptible to contamination by microorganisms and foodborne pathogens, which cause serious economic losses and health hazards. The large consumption and waste of meat and meat products means that there is a need for safe and effective preservation methods. Furthermore, toxicological aspects of chemical preservation techniques related to major health problems have sparked controversies and have prompted consumers and producers to turn to natural preservatives. Consequently, natural preservatives are being increasingly used to ensure the safety and quality of meat products as a result of customer preferences and biological efficacy. However, information on the current status of these preservatives is scattered and a comprehensive review is lacking. Here, we review current knowledge on the classification, mechanisms of natural preservatives and their applications in the preservation of meat and meat products, and also discuss the potential of natural preservatives to improve the safety of meat and meat products. The current status and the current research gaps in the extraction, application and controlled-release of natural antibacterial agents for meat preservation are also discussed in detail. This review may be useful to the development of efficient food preservation techniques in the meat industry. © 2024 Society of Chemical Industry.

Novel films of pectin extracted from ambarella fruit peel and jackfruit seed slimy sheath: Effect of ionic crosslinking on the properties of pectin film

Here, we prepared ionically crosslinked films using pectin extracted from agro-wastes, specifically ambarella peels (AFP) and jackfruit seed slimy sheath (JFS). Physiochemical properties of pectins, including moisture content, molecular weight (Mw), degree of esterification (DE), and galacturonic acid (GA), were analyzed. Optimal extraction was determined, i.e., citric acid concentration 0.3 M, time 60 min, solid/liquid ratio 1:25, and temperature 90 °C for AFP or 85 °C for JFS. Pectin yields under these conditions were 29.67 % ± 0.35 % and 29.93 ± 0.49 %, respectively. AFP pectin revealed Mw, DE, and GA values of 533.20 kDa, 67.08 % ± 0.68 %, and 75.39 ± 0.82 %, while JFS pectin exhibited values of 859.94 kDa, 63.04 % ± 0.47 %, and 78.63 % ± 0.71 %, respectively. The pectin films crosslinked with Ca2+, Cu2+, Fe3+, or Zn2+ exhibited enhanced tensile strength and Young's modulus, along with reduced elongation at break, moisture content, water solubility, water vapor permeability, and oxygen permeability. Structural analyses indicated metal ions were effectively crosslinked with carboxyl groups of pectin. Notably, the Cu2+-crosslinked film demonstrated superior water resistance, mechanical properties, and exhibited the highest antioxidant and antibacterial activities among all tested films. Therefore, the pectin films represent a promising avenue to produce eco-friendly food packaging materials with excellent properties.

Polyvinyl alcohol/kappa-carrageenan-based package film with simultaneous incorporation of ferric ion and polyphenols from Capsicum annuum leaves for fruit shelf-life extension

Bio-based food packaging materials have elicited growing interests due to their great degradability, high safety and active biofunctions. In this work, by simultaneously introducing the polyphenolic extracts from Capsicum annuum leaves and ferric ion (Fe3+) into the Polyvinyl alcohol/kappa-carrageenan (PVA/κ-carrageenan)-based film-forming matrix, an active package film was developed, with the purpose to improve the food shelf life. The experimental results indicated that the existence of Fe3+ can not only improve the mechanical properties owing to the multiple dynamic coordinated interactions, but also endow the composite films with excellent fire-retardancy. Moreover, the composite films could display excellent UV resistant performance, water vapor/oxygen gas barrier properties and antioxidant activities with the corporation of polyphenols. In particular, the highest DPPH and ABTS radical scavenging capacities for composite film (PC-PLP7 sample) were evaluated to be 82.5 % and 91.1 %, respectively. Higher polyphenol concentration is favorable to the bio-functions of the materials. Benefitting from these features, this novel kind of films with a dense and steady micro-structure could be further applicated in fruit preservations, where the ripening bananas were ensured with the high storage quality. This integration as a prospective food packaging material provides an economic and eco-friendly approach to excavate the high added-values of biomass.

Cassia Seed Gum Films Incorporated with Partridge Tea Extract as an Edible Antioxidant Food Packaging Film for Preservation of Chicken Jerky

The use of edible packaging films to delay food spoilage has attracted widespread attention. In this study, partridge tea extract (PTE) was added to cassia gum (CG) to prepare CG/PTE films. The microstructure, optical, mechanical, barrier, and antioxidant properties of CG/PTE films were investigated, and the effect of PTE on CG films was shown. The films had high transparency and smooth surface structure. Additionally, PTE significantly improved the elongation at break and antioxidant activity of films. At 2.5% of PTE, the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging rate of the film was 46.88% after diluting 50 times, indicating excellent antioxidant property, which could be applied to food preservation. After 9 days of storage, the thiobarbituric acid reactive substances values (TBARS) of chicken jerk packaged with films containing 0% and 2.5% PTE increased from 0.12% to 1.04% and 0.11% to 0.40%, respectively. This study suggests that CG/PTE films can be used to preserve cooked meat.

Incorporation of cellulose nanocrystals to improve the physicochemical and bioactive properties of pectin-konjac glucomannan composite films containing clove essential oil

This study aimed to investigate the effectiveness of cellulose nanocrystals (CNC) isolated from cotton in augmenting pectin (PEC)/konjac glucomannan (KGM) composite films containing clove essential oil (CEO) for food packaging application. The effects of CNC dosage on film properties were examined by analyzing the rheology of film-forming solutions and the mechanical, barrier, antimicrobial, and CEO-release properties of the films. Rheological and FTIR analysis revealed the enhanced interactions among the film components after CNC incorporation due to its high aspect ratio and abundant hydroxyl groups, which can also prevent CEO droplet aggregation, contributing to form a compact microstructure as confirmed by SEM and 3D surface topography observations. Consequently, the addition of CNC reinforced the polysaccharide matrix, increasing the tensile strength of the films and improving their barrier properties to water vapor. More importantly, antibacterial, controlled release and kinetic simulation experiments proved that the addition of CNC could further slow down the release rate of CEO, prolonging the antimicrobial properties of the films. PEC/KGM/CEO composite films with 15 wt% CNC was found to have relatively best comprehensive properties, which was also most effective in delaying deterioration of grape quality during the storage of 9 days at 25 °C.

Exploring the potential of jujube seed powder in polysaccharide based functional film: Characterization, properties and application in fruit preservation

In this study, we fabricated a novel biodegradable functional film using natural polysaccharides by adding jujube seed powder as an active ingredient. Scanning electron microscopy analysis showed agglomerate formation in the film with increasing concentration of seed powder. Fourier transform-infrared spectroscopy study demonstrated an electrostatic interaction between pectin and chitosan. The water solubility and swelling degree significantly decreased from 55.5 to 47.7 % and 66.0 to 41.9 %, respectively, depicting the film's water resistance properties. Higher opacity and lower transmittance value of the film indicated its protective effect towards light-induced oxidation of food. It was observed that the fabricated active film biodegraded to 82.33 % in 6 days. The DPPH radical scavenging activity of 98.02 % was observed for the functional film. The film showed antifungal activity against B. cinerea and P. chrysogenum. The highest zone of inhibition was obtained against food spoiling bacteria B. subtilis followed by S. aureus, P. aeruginosa and E. coli. Genotoxicity studies with the fabricated film showed a mitotic index of 8 % compared to 3 % in the control film. We used the fabricated film to preserve grapefruits, and the result showed that it could preserve grapes for ten days with an increase in antioxidant activity and polyphenolic content.

Design and preparation of novel antioxidant and antibacterial films containing procyanidins and phycocyanin for food packaging

The purpose of this study was to design a novel antioxidant and antibacterial film for food packaging using food-grade raw materials. The films were designed and fabricated based on carboxymethyl chitosan and pectin incorporated with procyanidins (PCs) and phycocyanin (Phy) by the tape casting method. The effects of different proportions of PCs and Phy on the properties and functions of the prepared films were studied. The results showed that the thickness of films could range from 55 to 70 μm, with dense network structure and uniform distribution of elements. Compared with C-Film group, the film loaded with PCs and Phy had lower water solubility and swelling rate, and higher tensile strength and elongation at break. FITR and XRD spectra revealed the molecular interaction mechanism among carboxymethyl chitosan, pectin, PCs and Phy, which could effectively endow the films with ultraviolet barrier properties. Moreover, the addition of PCs and Phy could effectively improve the antioxidant capacity and antibacterial effect of films, for example, the free radical scavenging abilities of most films were above 80% when the concentration of PCs was 40 μg mL-1. In view of these functional properties, the prepared film containing PCs and Phy have been successfully used in food packaging, which was proved by the preservation experiment of grapes. This study can provide theoretical and technical guidance for the preparation of biodegradable antibacterial films, and their application in the food packaging field.

Interaction mechanisms of edible film ingredients and their effects on food quality

Traditional food packaging has problems such as nondegradable and poor food safety. Edible films play an important role in food packaging, transportation and storage, having become a focus of research due to their low cost, renewable, degradable, safe and non-toxic characteristics. According to the different materials of edible films substrate, edible films are usually categorized into proteins, polysaccharides and composite edible films. Functional properties of edible films prepared from different substrate materials also vary, single substrate edible films are defective in some aspects. Functional ingredients such as proteins, polysaccharides, essential oils, natural products, nanomaterials, emulsifiers, and so on are commonly added to edible films to improve their functional properties, extend the shelf life of foods, improve the preservation of sensory properties of foods, and make them widely used in the field of food preservation. This paper introduced the classification, characteristics, and modification methods of common edible films, discussed the interactions among the substrate ingredients of composite edible films, the influence of functional ingredients on the properties of edible films, and the effects of modified edible films on the quality of food, aiming to provide new research ideas for the wide application and further study of edible films.

Fabrication of Schiff-base crosslinked films modified dialdehyde starch with excellent UV-blocking and antibacterial properties for fruit preservation

Starch-based films have received considerable attention, owing to their commendable biocompatible and biodegradable properties; however, their poor ultraviolet (UV)-blocking and antibacterial performances limit their application in fruit preservation. Herein, bio-based bifunctional benzoxazine (Bi-BOZ) compounds with different carbon chain lengths were synthesized, and the influence of chain lengths on the antibacterial effect was explored. Benzoxazine with 1,12-dodecanediamine as the amine source (BOZ-DDA) exhibited excellent antibacterial and antibiofilm activities, with minimum inhibitory concentrations of 21.7 ± 2.2 and 23.3 ± 2.6 μg/mL against Escherichia coli and Staphylococcus aureus, respectively, mainly because the electrostatic attraction and hydrophobic effect of BOZ-DDA, effectively disrupted the bacterial integrity. DS/DDA films with hydrophobic, antibacterial, and UV-resistant abilities were prepared by the Schiff-base reaction between BOZ-DDA and dialdehyde starch (DS). The interactions between the films increased with BOZ-DDA content, enhanced mechanical and barrier properties. DS/DDA films exhibited acid-responsive antibacterial activity attributed to the acid hydrolysis of Schiff bases, released of BOZ-DDA from the films, and the protonation of BOZ-DDA. DS/DDA films exhibited commendable antibacterial and anti-ultraviolet characteristics compared to commercially available films, allowing them to prevent the degradation of mangoes and grapes. As sustainable antibacterial materials, the multifunctional DS/DDA films manifest promising prospects in fruit preservation packaging applications.

Fluorescence and pectinase double-triggered chitosan/pectin/calcium propionate/curcumin-β-cyclodextrin complex film for pork freshness monitoring and maintenance

An intelligent and active food packaging film based on chitosan (CS), pectin (P), calcium propionate (CP), and curcumin-β-cyclodextrin complex (Cur-β-CD) was prepared. The CS/P/CP/Cur-β-CD film exhibited improved hydrophobicity (74.78 ± 0.53°), water vapor (4.55 ± 0.16 × 10-11 g·(m·s·Pa)-1), and oxygen (1.50 ± 0.06 × 10-12 g·(m·s·Pa)-1) barrier properties, as well as antioxidant (72.34 ± 3.79 % for DPPH and 86.05 ± 0.14 % for ABTS) and antibacterial (79.41 ± 2.89 % for E. coli and 83.82 ± 3.96 % for S. aureus) activities. The release of CP and Cur could be triggered by pectinase, with their cumulative release reaching 92.62 ± 1.20 % and 42.24 ± 1.15 %, respectively. The CS/P/CP/Cur-β-CD film showed delayed alterations in surface color, pH value, total volatile bases nitrogen, total viable counts, thiobarbituric acid reactive substance, hardness, and springiness of pork. Additionally, the fluorescence intensity of the film gradually decreased. In conclusion, we have developed a pH-responsive film with pectinase-triggered release function, providing a new concept for the design of multi-signal responsive intelligent food packaging.

Effect of tea polyphenols on chitosan packaging for food preservation: Physicochemical properties, bioactivity, and nutrition

Chitosan packaging has been widely studied for food preservation, the application of which is expanded by the incorporation of tea polyphenols. This paper reviews the influence of tea polyphenols incorporation on chitosan-based packaging from the perspectives of physicochemical properties, bioactivity used for food preservation, and nutritional value. The physicochemical properties included optical properties, mechanical properties, water solubility, moisture content, and water vapor barrier property, concluding that the addition of tea polyphenols improved the opacity, water solubility, and water vapor barrier property of chitosan packaging, and the mechanical properties and water content were decreased. The bioactivity used for food preservation, that is antioxidant and antimicrobial properties, is enhanced by tea polyphenols, improving the preservation of food like meat, fruits, and vegetables. In the future, efforts will be needed to improve the mechanical properties of composite film and adjust the formula of tea polyphenols/chitosan composite film to apply to different foods. Besides, the identification and development of high nutritional value tea polyphenol/chitosan composite film is a valuable but challenging task. This review is expected to scientifically guide the application of tea polyphenols in chitosan packaging.

Preparation, physicochemical and biological evaluation of chitosan Pleurotus ostreatus polysaccharides active films for food packaging

The aim of this study was to create CS-POP composite films by blending Pleurotus ostreatus stalk polysaccharides (POP) and chitosan (CS). The effects of adding different concentrations (0 %, 0.25 %, 0.5 %, 0.75 %, and 1 %) of POP on the mechanical, barrier, and optical properties of the CS films were investigated. When the POP content is at 0.5 %, the tensile strength of the composite film reaches its maximum value at 13.691 MPa, showing a significant improvement compared to the tensile strength of the pure CS film. The structure of the CS and CS-POP composite films was characterized by FT-IR spectroscopy, XRD, TGA and SEM. The results indicate that due to the interaction between the two types of CS and POP, the formation of Schiff base, and the intermolecular hydrogen bonds between CS and POP, the addition of POP to CS films can result in a smoother and more stable crystalline structure in the composite film. The CS-POP composite films exhibited enhanced antioxidant and antibacterial activity compared to the CS films alone, with the highest DPPH scavenging activity of 72.43 %. The composite films also showed significant inhibitory effects on the growth of E. coli.

Physicochemical, antibacterial and food preservation properties of active packaging films based on chitosan/ε-polylysine-grafted bacterial cellulose

To address the environmental and food contamination issues caused by plastics and microorganisms, antimicrobial films using natural polymers has attracted enormous attention. In this work, we proposed a green, convenient and fast approach to prepare antimicrobial films from chitosan (CS), bacterial cellulose (BC) and ε-polylysine (ε-PL). The effects of different concentrations of ε-PL (0 %, 0.25 %, 0.5 %, 0.75 %, 1 %, w/v) on the physicochemical properties and antibacterial activity of composite films (CS-DABC-x%PL) were systematically investigated. Furthermore, a comprehensive comparison with purely physically mixed CS-BC-x%PL films provides a deeper understanding of the subject matter. Characterization tests of the films were conducted using scanning electron microscope (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results suggested that the incorporation of 0.5 % ε-PL reduced the water solubility of the composite film by 19.82 %, along with improved the tensile strength and thermal stability by 37.31 % and 28.54 %. As ε-PL concentration increased to 1 %, the antibacterial performance of the films gradually enhanced. Additionally, the CS-DABC-0.5%PL film demonstrated effectiveness in delaying the deterioration of tilapia. These findings imply that this novel green packaging material holds significant potential in food preservation due to its promising antibacterial properties.

Effect of steam explosion on the morphological, textural, and compositional characteristics of betel nut

To reduce the adverse physical effects on the oral mucosa caused by excessive hardness of betel nut fibers, steam explosion was used to soften betel nuts. The effect of three operating parameters (pressure holding time, explosion pressure, and initial moisture content) on the morphology, texture, and chemical composition of the betel nuts was investigated. The fiber hardness and Shore hardness decreased by 56.17%-89.28% and 7.03%-34.29%, respectively, and the transverse tensile strength and fiber tensile strength also decreased by up to 60.72% and 24.62%, respectively. Moreover, the coefficient of static friction and moisture content increased. After steam explosion, the betel nut increased in transverse diameter, became darker and more yellow-red in color, and showed a damaged microstructure. The contents of free phenol and alkaloids decreased after steam explosion treatment, with free phenols and total alkaloids decreasing from 34.32 mg(GAE)/g and 7.84 mg/g to 21.58 mg(GAE)/g and 6.50 mg/g, respectively, after the A-50 s treatment condition. The steam explosion increased the quantity of phenols, alkaloids, and soluble solids released from the betel nut under the same simulated release conditions of the texture analyzer. The research also showed that increased pressure holding time and explosion pressure enhanced the explosion efficiency, while the initial moisture content was reduced the explosion efficiency. Therefore, steam explosion is an effective pretreatment approach to soften betel nut and facilitate healthy development of the betel nut industry.

Recent advances in edible coatings and their application in food packaging

The food packaging industries are facing the challenge of food waste generation. This can be addressed through the use of edible coating materials. These coatings aid in extending the shelf life of food products, reducing waste. The key components of these coatings include food-grade binding agents, solvents, and fillers. The integration of polysaccharide, protein, lipids, bioactive and composite-based materials with edible coating matrix aids to combat substantial post-harvest loss of highly perishable commodities and elevates the quality of minimally processed food. The aim of this review is to introduce the concept of edible coatings and discuss the different coating materials used in the food industry, along with their properties. Additionally, this review aims to classify the coating types based on characteristic features and explore their application in various food processing industries. This review provides a comprehensive overview of edible coatings, including the integration of polysaccharides, proteins, lipids, bioactive, and composite-based materials into the coating matrix. This review also addresses the significant post-harvest loss of highly perishable commodities and emphasizes the enhancement of quality in minimally processed food. Furthermore, the antimicrobial, anti-corrosive, and edible characteristics are highlighted, showcasing their potential applications in different food packaging industries. Moreover, it also discusses the challenges, safety and regulatory aspects, current trends, and future perspectives, aiming to shed light on the commercialization and future investigation of edible coatings.

Extraction Methods, Properties, Functions, and Interactions with Other Nutrients of Lotus Procyanidins: A Review

Lotus procyanidins, natural polyphenolic compounds isolated from the lotus plant family, are widely recognized as potent antioxidants that scavenge free radicals in the human body and exhibit various pharmacological effects, such as anti-inflammatory, anticancer, antiobesity, and hypoglycemic. With promising applications in food and healthcare, lotus procyanidins have attracted extensive attention in recent years. This review provides a comprehensive summary of current research on lotus procyanidins, including extraction methods, properties, functions, and interactions with other nutrient components. Furthermore, this review offers an outlook on future research directions, providing ideas and references for the exploitation and utilization of lotus.

Enzyme-Assisted Extraction of Ulvan from the Green Macroalgae Ulva fenestrata

Ulvan is a sulfated polysaccharide extracted from green macroalgae with unique structural and compositional properties. Due to its biocompatibility, biodegradability, and film-forming properties, as well as high stability, ulvan has shown promising potential as an ingredient of biopolymer films such as sustainable and readily biodegradable biomaterials that could replace petroleum-based plastics in diverse applications such as packaging. This work investigates the potential of Ulva fenestrata as a source of ulvan. Enzyme-assisted extraction with commercial cellulases (Viscozyme L and Cellulysin) and proteases (Neutrase 0.8L and Flavourzyme) was used for cell wall disruption, and the effect of the extraction time (3, 6, 17, and 20 h) on the ulvan yield and its main characteristics (molecular weight, functional groups, purity, and antioxidant capacity) were investigated. Furthermore, a combined process based on enzymatic and ultrasound extraction was performed. Results showed that higher extraction times led to higher ulvan yields, reaching a maximum of 14.1% dw with Cellulysin after 20 h. The combination of enzymatic and ultrasound-assisted extraction resulted in the highest ulvan extraction (17.9% dw). The relatively high protein content in U. fenestrata (19.8% dw) makes the residual biomass, after ulvan extraction, a potential protein source in food and feed applications.

Health benefits, mechanisms of interaction with food components, and delivery of tea polyphenols: a review

Tea polyphenols (TPs) are the most important active component of tea and have become a research focus among natural products, thanks to their antioxidant, lipid-lowering, liver-protecting, anti-tumor, and other biological activities. Polyphenols can interact with other food components, such as protein, polysaccharides, lipids, and metal ions to further improve the texture, flavor, and sensory quality of food, and are widely used in food fields, such as food preservatives, antibacterial agents and food packaging. However, the instability of TPs under conditions such as light or heat and their low bioavailability in the gastrointestinal environment also hinder their application in food. In this review, we summarized the health benefits of TPs. In order to better use TPs in food, we analyzed the form and mechanism of interaction between TPs and main food components, such as polysaccharides and proteins. Moreover, we reviewed research into optimizing the applications of TPs in food by bio-based delivery systems, such as liposomes, nanoemulsions, and nanoparticles, so as to improve the stability and bioactivity of TPs in food application. As an effective active ingredient, TPs have great potential to be applied in functional food to produce benefits for human health.

A novel film based on gluten, pectin, and polyphenols and its potential application in high-fat food

BACKGROUND

A novel film based on some natural ingredients (wheat gluten, pectin, and polyphenols) was used to improve the quality and storage stability of high-fat food due to their good sustainable, mechanical, and edible properties.

RESULTS

With the addition of polyphenols from Cedrus deodara (in the form of pine-needle extract (PNE)), the physicochemical properties (thickness, moisture content, and color), mechanical properties (tensile strength and elongation), barrier properties (water vapor, oil, and oxygen permeability, transmittance), and thermal stability of the composite film were improved. According to the analysis of infrared spectroscopy and molecular docking, the main compounds of PNE interacted with wheat gluten by hydrogen bonds and hydrophobic forces to form a compact and stable structure. In addition, the composite film showed a remarkable antioxidant capability to scavenge free radicals, and the film matrix could effectively protect the antioxidant activity of PNE. Furthermore, using cured meat as a model, the composite film exhibited a fine packaging performance in high-fat food during storage, which could obviously inhibit the excessive oxidation of fat and protein of cured meat and was beneficial in forming its special flavor.

CONCLUSION

Our results suggest that the composite film possessed good properties and had potential for packing of high-fat foods, which could improve the quality and safety of food during processing and storage. © 2023 Society of Chemical Industry.

Nanoemulsion-Based Multilayer Films for Ground Beef Preservation: Antimicrobial Activity and Physicochemical Properties

This study aimed to improve the physical, mechanical, and biological properties of a monolayer pectin (P) film containing nanoemulsified trans-Cinnamaldehyde (TC) by incorporating it between inner and outer layers of ethylcellulose (EC). The nanoemulsion had an average size of 103.93 nm and a zeta potential of -46 mV. The addition of the nanoemulsion increased the opacity of the film, reduced its moisture absorption capacity, and improved its antimicrobial activity. However, the tensile strength and elongation at break of the pectin films decreased after the incorporation of nanoemulsions. Multilayer films (EC/P/EC) showed a higher resistance to breaking and better extensibility compared to monolayer films. The antimicrobial activity of both mono and multilayer films was effective in inhibiting the growth of foodborne bacteria during storage of ground beef patties at 8 °C for 10 days. This study suggests that biodegradable antimicrobial multilayer packaging films can be effectively designed and applied in the food packaging industry.

Chitosan Based Biodegradable Composite for Antibacterial Food Packaging Application

A recent focus on the development of biobased polymer packaging films has come about in response to the environmental hazards caused by petroleum-based, nonbiodegradable packaging materials. Among biopolymers, chitosan is one of the most popular due to its biocompatibility, biodegradability, antibacterial properties, and ease of use. Due to its ability to inhibit gram-negative and gram-positive bacteria, yeast, and foodborne filamentous fungi, chitosan is a suitable biopolymer for developing food packaging. However, more than the chitosan is required for active packaging. In this review, we summarize chitosan composites which show active packaging and improves food storage condition and extends its shelf life. Active compounds such as essential oils and phenolic compounds with chitosan are reviewed. Moreover, composites with polysaccharides and various nanoparticles are also summarized. This review provides valuable information for selecting a composite that enhances shelf life and other functional qualities when embedding chitosan. Furthermore, this report will provide directions for the development of novel biodegradable food packaging materials.

Insights into the Edible and Biodegradable Ulvan-Based Films and Coatings for Food Packaging

Recently, edible films or coatings that are made from algal polysaccharides have become promising candidates for replacing plastic-based packaging materials for food storage due to their non-toxic, biodegradable, biocompatible, and bioactive characteristics. Ulvan, a significant biopolymer with unique functional properties derived from marine green algae, has been extensively used in various sectors. However, there are fewer commercial applications of this sugar in the food packaging industry compared to many other algae-derived polysaccharides, such as alginates, carrageenan, and agar. This article aims to review the unparalleled chemical composition/structure and physiochemical properties of ulvan and the latest developments in ulvan-based edible films and coatings, thus highlighting their potential applications in the food packaging industry.

Caseinate-reinforced pectin hydrogels: Efficient encapsulation, desirable release, and chemical stabilization of (-)-epigallocatechin

(-)-Epigallocatechin (EGC) has good health benefits, but its chemical stability is low. Pectin hydrogels have potential for the encapsulation and delivery of EGC, but they are limited by porous networks and poor mechanical properties. In this study, protein (whey protein isolate and caseinate)-reinforced pectin hydrogel beads (HB_PEC-WPI and HB_PEC-CAS) were developed to overcome these limitations. The results showed that HB_PEC-CAS was a superior delivery system for EGC. HB_PEC-CAS had a compact network structure, mainly because of the hydrogen bonds that formed between caseinate and pectin. Moreover, the EGC encapsulation efficiency of HB_{PEC-CAS (2.4%)} reached 92.23 %; HB_{PEC-CAS (2.4%)} could also delay the release of EGC in an aqueous environment, while ensuring its sufficient release in a simulated gastrointestinal environment. Notably, EGC was chemically stabilized in HB_{PEC-CAS (2.4%)} during a 6-day storage period at 37 °C through the inhibition of its epimerization, oxidation, dimerization, and trimerization. The numerous hydroxyl groups in EGC readily interacted with the exposed amino acid residues in caseinate and created more protective sites. This study developed a strategy for protein-reinforced pectin hydrogel development and approaches for the protection of tea polyphenols; the findings offer useful insights for the tea-based food and beverage industry.

Potato Starch-Based Film Incorporated with Tea Polyphenols and Its Application in Fruit Packaging

Effects of tea polyphenols (TP) on the physical properties, barrier properties and functionality of potato starch-based film were determined, while the interaction mechanism between TP and starch in film and the application of this film in fruit packaging were further evaluated. TP exhibited different effects on the physical properties of potato starch-based film, including thickness (0.083 to 0.087 mm), moisture content (9.27% to 9.68%), color (ΔE value: 5.41 to 10.55), light transmittance (51% to 62%), tensile properties and thermal properties, and improved its barrier properties, including water vapor permeability (9.68 to 11.84 × 10-11 g m-1 s-1 Pa-1),oxygen permeability (1.25 to 2.78 × 10-16 g m-1 s-1 Pa-1) and antioxidant activity. According to the determination of wide-angle X-ray diffraction, Fourier transform infrared and scanning electron microscope, TP could interact with starch chains via hydrogen bonds to form non-crystal complexes, thus affecting the cross-linking among starch chains and further changing the microstructure of film. Furthermore, film incorporated with TP could improve the storage quality (including weight and texture) of blueberries, and inhibit the enzymatic browning of fresh-cut bananas during storage. All present results suggested that tea polyphenols had potential to enhance the properties and function of potato starch-based film, and the film exhibited the application prospect in fruit packaging and preservation.

Ultrasound-assisted development and characterization of novel polyphenol-loaded pullulan/trehalose composite films for fruit preservation

A novel food packaging film was developed by incorporating a tea polyphenols-loaded pullulan/trehalose (TP@Pul/Tre) into a composite film with ultrasound-assisted treatment of dual-frequency (20/35 kHz, 40 W/L) for 15 min to assess the physicochemical and mechanical properties of a composite film. The optimized ultrasound-assisted significantly increases elongation at break, tensile strength, and improves the composite film's UV/water/oxygen barrier properties. Structure analysis using attenuated total reflectance-Fourier transform infrared, X-ray diffraction and thermal stability revealed that these improvements were achieved through ultrasound-enhanced H-bonds, more ordered molecular arrangements, and good intermolecular compatibility. Besides, the ultrasound-assisted TP@Pul/Tre film has proven to have good antibacterial performance against Escherichia coli and Staphylococcus aureus, with approximately 100 % lethality at 4 h and 8 h, respectively. Moreover, the ultrasound-assisted TP@Pul/Tre film effectively delayed moisture loss, oxidative browning, decay, and deterioration in fresh-cut apples and pears, thereby extending their shelf life. Thus, ultrasound has proved to be an effective tool for improving the quality of food packaging films, with a wide range of applications.