Preparation and characterization of konjac glucomannan-based bionanocomposite film for active food packaging

pH-responsive composite konjac glucomannan/xanthan gum film incorporated lysozyme fibril for the monitoring of chicken breast freshness

A pH responsive composite film was developed by incorporating cyanidin (CY) and egg white lysozyme fibril into konjac glucomannan (KGM) and xanthan gum (XG) matrix to monitor the chicken breast freshness in this work. The physicochemical properties of the films, especially pH sensitivity, evaluated by color difference and visual color change under different pH values, were first explored. The freshness changes of chicken breast sealed with the composite films were also analyzed. Hydrogen bonding and electrostatic interaction formed between the components of the composite film. Moreover, the characterizations of pH responsiveness, thermal stability, and barrier property indicated the benefits of incorporating CY and lysozyme fibril into KGM/XG films. The KGM/XG/lysozyme fibril/CY (KXLCY) film showed superior biodegradability in soil. KXLCY composite film reduced the weight loss and delayed the spoilage and fat oxidation rate of chicken breast. In addition, the color of KXLCY film changed from purple red to purple and then to blue during the storage of the packaged chicken breast, indicating a real-time freshness monitoring effect. This work provided a solid scientific foundation for the development of active pH intelligent colorimetric films and their application in food freshness evaluation.

Nanoencapsulation of active compounds in chitosan by ionic gelation: Physicochemical, active properties and application in packaging

The ionic gelation technique using chitosan to encapsulate active compounds has received lots of attention in the literature due to its ease-of-use and known biodegradability, biocompatibility and antimicrobial properties of the polymer. In this review, main studies from the last five years involving encapsulation of active compounds (natural and commercial/synthetic) are brought together in order to understand the encapsulation mechanisms of components with chitosan as well as the physical, chemical and morphological properties of the resulting particles. The application of these nanostructures in polymeric films was then investigated, since additives for packaging are an attractive premise and have only recently started being studied in the literature. Herein, comparisons are made between free and encapsulated bioactive compounds in different film matrices, as well as the effect of this activation on structure. Finally, this work details the mechanisms involved in the production of chitosan nanoparticles with active compounds and encourages new studies to focus on their application in packaging.

The amyloid fibril-stabilized Pickering emulsion significantly enhances the mechanical and barrier properties of Konjac Glucomannan active films for cherry preservation

Konjac glucomannan (KGM), a natural polymer, is an excellent candidate for use in food packaging due to its desirable film-forming characteristics. However, the limited barrier, antioxidant, and antimicrobial properties of pure KGM films restrict their practical applications. To reinforce the barrier and functional properties of KGM-based films, tea tree oil (TTO) Pickering emulsions stabilized by chitosan-modified soy protein derivative-amyloid fibril (AFS) were prepared and incorporated into KGM matrices. The effects of these Pickering emulsions on the structural and functional properties of KGM films were systematically investigated. The results indicated a favorable compatibility between Pickering emulsions and KGM. The strong interactions among KGM, AFS, and TTO lead to a denser and more compact film structure, improving barrier properties. Specifically, the water vapor and oxygen permeability values of the Pickering emulsion films (group E4C1) were reduced to 0.326 g·mm/(m2·day·KPa) and 4.63 g/m·s·Kpa, respectively. The tensile strength and elongation at the break of the film were increased respectively to 35.02 MPa and 71.8 %. The incorporation of TTO markedly enhanced water resistance, with the total antioxidant capacity of group E5C1 being 9.92 times greater than that of pure KGM films, as well as improving the antimicrobial activity of the KGM-based films. Furthermore, the emulsion film demonstrated effective preservation of cherries, extending their shelf life by approximately 10 days. In conclusion, this study successfully developed a film with enhanced barrier properties and antimicrobial activity, presenting promising applications in food preservation and packaging.

Enhancing Strawberry Freshness: Multifunction Sustainable Films Utilizing Two Types of Modified Carbon Nanotubes for Photothermal Food Packaging

Currently, antimicrobial films with stable and efficient antibacterial activities are receiving considerable attention in the food packaging industry. Herein, a chemically/physically linked konjac glucomannan-sodium alginate (KGM-SA)@carbon nanotubes (CNTs)/Fe3+ composite film with outstanding resistance to ultraviolet radiation, oxidation, and bacteria, as well as excellent photothermal effects and mechanical properties, was successfully prepared using a solvent flow method. Tannic acid-modified carboxyl-functionalized CNTs (TCCNTs), l-cysteine-modified carboxyl-functionalized CNTs (LCCNTs), and Fe3+ were incorporated into the prepared film. The film structure of KGM-SA@CNTs/Fe3+ was characterized using various methods, confirming the formation of a dual-cross-linked network through metal-coordination bonds and hydrogen bonding. This unique structure endowed the film with excellent water vapor permeability (3.58 g mm/m2 day kPa), water resistance (water contact angle = 93.66°), and thermal stability. Further, the film exhibited outstanding photothermal conversion efficiency and stability under near-infrared irradiation (300 mW/cm2) as well as excellent bactericidal properties against Staphylococcus aureus and Escherichia coli, achieving a bacterial inhibition rate of >99%. In a strawberry preservation experiment, the KGM-SA@CNTs/Fe3+ composite film exhibited remarkable preservation effects, extending the shelf life of strawberries by 4-6 d. Thus, this photothermal antibacterial film offers a new approach for the application of CNTs in food packaging.

Tailoring structural and mechanical properties of konjac glucomannan/curdlan composite hydrogels by freeze-thaw treatment

To improve the gelling properties of konjac glucomannan/curdlan (KGM/CUD) composite hydrogels, KGM/CUD composite hydrogels were treated by freeze-thawing. Herein, we focus on the effects of freeze-thaw cycles, freezing temperature, and freezing time on the structural and mechanical properties of KGM/CUD composite hydrogels. SEM and SAXS results showed that ice crystals generated by freezing extruded the molecular chains and increased the cross-linking density between molecular chains, which resulted in a denser gel microstructure. Among them, the freeze-thaw treatment at -20 °C for 12 h can effectively reduce the correlation length (ξ). According to mechanical testing, freeze-thawed gels for 48 h reached 408-, 826-, and 840-fold of the hardness, gumminess and chewiness of unfrozen, respectively. After freeze-thaw treatment, the energy storage modulus (G') of the gel increased to 9872 Pa, the residual mass after heating was up to 27.9 %, the water holding capacity (WHC) was reduced to 80.85 %. In addition, low-field nuclear magnetic resonance results confirmed that the freeze-thaw treatment promoted the formation of ice crystals from water molecules, which realized the transition of the water state, thus reducing the water mobility of the gel. This study provides a facile and efficient strategy for designing hydrogels products with exceptional texture and sensory characteristics.

The Use of Novel Colorimetric Films to Monitor the Freshness of Pork, Utilizing Konjac Glucomannan With Curcumin/Alizarin

In this study, different proportions of curcumin (CUR) and alizarin (ALI) were added to konjac glucomannan (KG)/ polyvinyl alcohol (PVA) to prepare an active intelligent packaging film and evaluate its potential to indicate pork freshness. The mixed indicator had a richer color hierarchy in the buffer solution with pH = 2-12. The surface of the KG-2C2A and KG-1C3A films is smoother and has fewer cross-section faults. With the increase of CUR content in the film, the crystal structure becomes more prominent, leading to poor compatibility with KG. The WAC of KG-3C1A and KG-1C3A films was significantly higher than that of the other groups, and they had better hydrophobicity. With the increase of CUR content in the films, the thermal stability of the films was enhanced, and the KG-C films showed the highest thermal stability. Among them, the KG-2A2C and KG-1C3A films showed the most significant color change during pork spoiling and could be used to monitor the freshness of pork. As a pH colorimetric indicator, CUR and ALI-coated KG films might be of great potential in fresh meat monitoring.

Improving the performance of kraft paper by cinnamon essential oil/soybean protein isolate microcapsules and konjac glucomannan for citrus preservation

In order to reduce the quality loss of citrus and extend its storage time after harvest, it is essential to develop coated kraft papers with antibacterial and fresh-keeping properties. In this study, cinnamon essential oil (CEO)/soybean protein isolate (SPI) microcapsules were prepared by the coagulation method, and their properties were optimized. Then, the microcapsules were added to konjac glucomannan (KGM) as a coating solution to enhance the physical, and chemical properties of kraft paper by a coating method. The release behavior of CEO, tensile properties, antibacterial properties and preservation effects of the paper were investigated. The results show that when the ratio of wall to core was 7:3, the highest encapsulation rate was 92.20 ± 0.43 %. The coating treatment significantly reduced the oxygen and water vapor transmission rates of kraft paper. The shelf life of citrus treated with coated Kraft was extended by >10 days. Thus, the CEO/SPI microencapsulation and KGM coating could improve the properties of kraft paper and have the potential for citrus preservation.

pH-responsive IPN beads of carboxymethyl konjac glucomannan and sodium carboxymethyl cellulose as a controlled release carrier for ibuprofen

The convergence of polymer and pharmaceutical sciences has advanced drug delivery systems significantly. Carbohydrate polymers, especially carboxymethylated ones, offer versatile benefits for pharmaceuticals. Interpenetrating polymer networks (IPNs) combine synthetic and natural polymers to enhance drug delivery. The study aims to develop IPN beads using sodium carboxymethyl cellulose (SCMC) and carboxymethyl konjac glucomannan (CMKGM) for controlled release of ibuprofen (IB) after oral administration. Objectives include formulation optimization, characterization of physicochemical properties, evaluation of pH-dependent swelling and drug release behaviors to advance biocompatible and efficient oral drug delivery systems. The beads were analyzed using SEM, FTIR, DSC, and XRD techniques. Different ratio of polymers (CMKGM:SCMS) and crosslinker concentrations (2&4 %w/v) were used, significantly impacting bead size, swelling, drug encapsulation, and release characteristics. DSC results indicated higher thermal stability in IPN beads compared to native polymers. XRD revealed IB dispersion within the polymer matrix. IPN beads size ranged from 580 ± 0.56 to 324 ± 0.27 μm, with a nearly spherical shape. IPN beads exhibited continuous release in alkaline conditions (pH 7.4) and minimal release in acidic media (pH 1.2). These findings suggest that the formulated IPN beads can modulate drug release in both acidic and alkaline environments, potentially mitigating the gastric adverse effects often associated with oral administration of IB.

A Comprehensive Review on the Isolation, Bioactivities, and Structure-Activity Relationship of Hawthorn Pectin and Its Derived Oligosaccharides

Hawthorn (Crataegus pinnatifida Bunge) has been highlighted as an excellent source of a variety of bioactive polymers, which has attracted increasing research interest. Pectin, as a kind of soluble dietary fiber in hawthorn, is mainly extracted by hot water extraction and ultrasonic or enzymatic hydrolysis and is then extensively used in food, pharmaceutical, and nutraceutical industries. Numerous studies have shown that hawthorn pectin and its derived oligosaccharides exhibit a wide range of biological activities, such as antioxidant activity, hypolipidemic and cholesterol-reducing effects, antimicrobial activity, and intestinal function modulatory activity. As discovered, the bioactivities of hawthorn pectin and its derived oligosaccharides were mainly contributed by structural features and chemical compositions and were highly associated with the extraction methods. Additionally, hawthorn pectin is a potential resource for the development of emulsifiers and gelling agents, food packaging films, novel foods, and traditional medicines. This review provides a comprehensive summary of current research for readers on the extraction techniques, functional characteristics, structure-activity relationship, and applications in order to provide ideas and references for the investigation and utilization of hawthorn pectin and its derived oligosaccharides. Further research and development efforts are imperative to fully explore and harness the potential of hawthorn pectin-derived oligosaccharides in the food and medicine fields.

Organic nanoparticles incorporated starch/carboxymethylcellulose multifunctional coating film for efficient preservation of perishable products

Most of postharvest agricultural produces are perishable due to microorganisms infections and physiological change. Herein, one kind of multifunctional coating film of SC-ECCNPs was developed by incorporating organic nanoparticles of ECCNPs into starch/carboxymethylcellulose (SC) to prolong shelf life of food with excellent performances. The SC-ECCNPs coating was prepared with starch and sodium carboxymethylcellulose as film substrate (SC) to incorporate with organic nanoparticles of ECCNPs formed by integrating epigallocatechin-3-gallate (EGCG), cysteine (Cys), and cinnamaldehyde (CA). The incorporation of ECCNPs improves the UV-resistance and physical properties of SC-ECCNPs coating and also endows it with excellent antioxidative and broad-spectrum antibacterial activity. The application possibilities of SC-ECCNPs coating were explored with strawberries and oranges as samples, validating that the SC-ECCNPs coating can prolong the shelf life of fruits at room temperature. The biosafety of the coating was further confirmed with hemolysis and MTT experiments. The SC-ECCNPs coating film was prepared with natural substrates via a simple and green method. The investigation provides an instructive way for developing advanced packaging materials with high performances.

Improved physicochemical properties and in vitro digestion of walnut oil microcapsules with soy protein isolate and highly oxidized konjac glucomannan as wall materials

This study investigated the effect of the oxidation degrees of oxidized konjac glucomannan (OKGM) on the encapsulation efficiency (EE), physicochemical and in vitro digestive properties of soy protein isolate (SPI)-based microcapsules walnut oil using experimental and computational approaches. Microcapsules had the highest EE when the ratio of OKGM and SPI to oil was 2.5:1. With increasing the oxidation degree of OKGM, the EE of microcapsules was increased and the hygroscopicity was decreased. Molecular dynamics simulation results showed that SPI/oil/highly OKGM had relatively low binding energy (-4.03 × 106 kJ/mol) and strong electrostatic interactions, which may contribute to a higher EE and lower hygroscopicity of microcapsules, respectively. The oxidative stability of the oil was markedly improved by SPI and OKGM, and microcapsules prepared with SPI and highly OKGM had the highest in vitro digestion. This study provided theoretical support for broadening the application of microcapsules prepared with SPI and OKGM.

Electrospun Photodynamic Antibacterial Konjac Glucomannan/Polyvinylpyrrolidone Nanofibers Incorporated with Lignin-Zinc Oxide Nanoparticles and Curcumin for Food Packaging

Due to the growing concerns surrounding microbial contamination and food safety, there has been a surge of interest in fabricating novel food packaging with highly efficient antibacterial activity. Herein, we describe novel photodynamic antibacterial konjac glucomannan (KGM)/polyvinylpyrrolidone (PVP) nanofibers incorporated with lignin-zinc oxide composite nanoparticles (L-ZnONPs) and curcumin (Cur) via electrospinning technology. The resulting KGM/PVP/Cur/L-ZnONPs nanofibers exhibited favorable hydrophobic properties (water contact angle: 118.1°), thermal stability, and flexibility (elongation at break: 241.9%). Notably, the inclusion of L-ZnONPs and Cur endowed the nanofibers with remarkable antioxidant (ABTS radical scavenging activity: 98.1%) and photodynamic antimicrobial properties, demonstrating enhanced inhibitory effect against both Staphylococcus aureus (inhibition: 12.4 mm) and Escherichia coli (12.1 mm). As a proof-of-concept study, we evaluated the feasibility of applying nanofibers to fresh strawberries, and the findings demonstrated that our nanofibers could delay strawberry spoilage and inhibit microbial growth. This photodynamic antimicrobial approach holds promise for design of highly efficient antibacterial food packaging, thereby contributing to enhanced food safety and quality assurance.

Structural and Physiochemical Properties of Polyvinyl Alcohol-Succinoglycan Biodegradable Films

Polyvinyl alcohol (PVA)-bacterial succinoglycan (SG) biodegradable films were developed through a solvent-casting method. Effects of the PVA/SG ratio on the thickness, transmittance, water holding capacity, and structural and mechanical properties were investigated by various analytical methods. All the prepared films were transparent and uniform, and XRD and FTIR analyses confirmed that PVA was successfully incorporated into SG. The films also showed excellent UV-blocking ability: up to close to 80% with increasing SG concentration. The formation of effective intermolecular interactions between these polymers was evidenced by their high tensile strength and moisture transport capacity. By measuring the biodegradation rate, it was confirmed that films with high SG content showed the fastest biodegradation rate over 5 days. These results confirm that PVA/SG films are eco-friendly, with both excellent biodegradability and effective UV-blocking ability, suggesting the possibility of industrial applications as a packaging material in various fields in the future.

The present state and future outlook of pectin-based nanoparticles in the stabilization of Pickering emulsions

The stabilization of Pickering emulsions using micro/nanoparticles has gained significant attention due to their wide range of potential applications in industries such as cosmetics, food, catalysis, tissue engineering, and drug delivery. There is a growing demand for the development of environmentally friendly micro/nanoparticles to create stable Pickering emulsions. Naturally occurring polysaccharides like pectin offer promising options as they can assemble at oil/water interfaces. This polysaccharide is considered a green candidate because of its biodegradability and renewable nature. The physicochemical properties of micro/nanoparticles, influenced by fabrication methods and post-modification techniques, greatly impact the characteristics and applications of the resulting Pickering emulsions. This review focuses on recent advancements in Pickering emulsions stabilized by pectin-based micro/nanoparticles, as well as the application of functional materials in delivery systems, bio-based films and 3D printing using these emulsions as templates. The effects of micro/nanoparticle properties on the characteristics of Pickering emulsions and their applications are discussed. Additionally, the obstacles that currently hinder the practical implementation of pectin-based micro/nanoparticles and Pickering emulsions, along with future prospects for their development, are addressed.

Konjac glucomannan films incorporated pectin-stabilized Mandarin oil emulsions: Structure, properties, and application in fruit preservation

To enhance the water-resistance and antibacterial properties of KGM films, mandarin oil (MO), was directly emulsified by pectin and then dispersed to the KGM matrix. The effect of MO concentration (0, 0.5, 1.0, 1.5, and 2 wt%) on the performance of the film-forming emulsions as well as the emulsion films was investigated. The results revealed that pectin could encapsulate and protect MO, and KGM as film matrix could further contributed to the high stability of the film-forming emulsions. The FT-IR, XRD, and SEM suggested that MO stabilized by pectin was uniformly distributed in the KGM matrix. The compatibility and good interaction between KGM and pectin contributed to highly dense and compact structure. Furthermore, increasing the concentration of MO effectively improved water-resistance, oxygen barrier, and antimicrobial activity of the KGM based films. The 1.5 wt% MO loaded KGM film had the highest tensile strength (72.22 MPa) and water contact angle (θ = 95.73°), reduced the WVP and oxygen permeability by about 25.8 % and 32.8 times, respectively, prolonged the shelf life of strawberries for 8 days. As demonstrated, the 1.5 wt% MO-loaded KGM film has considerable potential for high-performance natural biodegradable active films to ensure food safety and reduce environmental impacts.

Edible film preparation by anthocyanin extract addition into acetylated cassava starch/sodium carboxymethyl cellulose matrix for oxidation inhibition of pumpkin seeds

In this study, an edible film was fabricated by incorporating anthocyanin extract from black rice (AEBR) into acetylated cassava starch (ACS)/carboxymethyl-cellulose (CMC) to enhance the shelf life of pumpkin seeds. The effects of AEBR on the rheological properties of film-forming solutions, as well as the structural characterization and physicochemical properties of the film, were evaluated. Rheological properties of solutions revealed that AEBR was evenly dispersed into polymer matrix and bound by hydrogen bonds, as confirmed by Fourier transform infrared spectroscopy analysis. The appropriate AEBR addition could be compatible with polymer matrix and formed a compact film structure, improving the mechanical properties, barrier properties, and opacity. However, with further addition of AEBR, the tensile strength and water vapor permeability decreased and the tight structure was destroyed. After being stored separately under thermal and UV light accelerated conditions for 20 days, the peroxide value and acid value of roasted pumpkin seeds coated with the AEBR film showed a significant reduction. Moreover, the storage stability of AEBR was improved through the embedding of ACS/CMC biopolymers. These results indicated that AEBR film could effectively delay pumpkin seeds oxidation and prolong their shelf life as an antioxidant material.

Pickering nanoemulsion loaded with eugenol contributed to the improvement of konjac glucomannan film performance

Konjac glucomannan (KGM) is becoming a very potential food packaging material due to its good film-forming properties and stability. However, KGM film has several shortcomings such as low mechanical strength, strong water absorption, and poor self-antibacterial performance, which limits its application. Therefore, in order to enhance the mechanical and functional properties of KGM film, this study prepared Pickering nanoemulsion loaded with eugenol and added it to the KGM matrix to explore the improvement effect of Pickering nanoemulsion on KGM film properties. Compared to pure KGM film and eugenol directly added film, the mechanical strength of Pickering-KGM film was significantly improved due to the establishment of ample hydrogen bonding interactions between the β-cyclodextrin inclusion complex system and KGM. Pickering-KGM film had significant antioxidant capacity than pure KGM film and eugenol directly added KGM film (eugenol-KGM film) (~3.21 times better than KGM film, ~0.51 times better than eugenol-KGM film). In terms of antibacterial activity, Pickering-KGM film had good inhibitory effect on Escherichia coli, Staphylococcus aureus, and Candida albicans, and raspberry preservation experiment showed that the shelf life of the Pickering-KGM film could be extended to about 6 days. To sum up, this study developed a novel means to improve the film performance and provide a new insight for the development and application of food packaging film.

Influence of chitin nanofibers and gallic acid on physical-chemical and biological performances of chitosan-based films

In this work, chitosan films loaded with gallic acid and different content of chitin nanofibers were prepared and subjected to different characterization techniques. The results showed that the inclusion of gallic acid to chitosan films caused moderate decrease in water vapor permeability (by 29 %) and increased tensile strength of films (by 169 %) in comparison to the neat chitosan films. Furthermore, it was found that the addition of chitin nanofibers up to 30 % into chitosan/gallic acid films additionally improved tensile strength (by 474 %) and reduced plasticity of films (by 171 %), when compared to the chitosan/gallic acid films. Increased concentration of chitin nanofibers in films reduced the overall water vapor permeability of films by 51 %. In addition, gallic acid and chitin nanofibers had synergic effect on high chitosan film's antioxidant and antifungal activity toward Botrytis cinerea (both above 95 %). Finally, chitosan/gallic acid/chitin nanofibers films reduced decay incidence of strawberries, increased total soluble solid content, and promoted high production of some polyphenols during cold storage, in comparison to the control chitosan films and uncoated strawberry samples. Hence, these results suggest that chitosan/gallic acid/chitin nanofibers can present eco-sustainable approach for preservation of strawberries, giving them additional nutritional value.

Antibacterial Micelles-Loaded Carboxymethyl Chitosan/Oxidized Konjac Glucomannan Composite Hydrogels for Enhanced Wound Repairing

Antibacterial hydrogels have emerged as a promising approach for effective wound treatment. However, despite extensive research on the fabrication of antibacterial hydrogels, it remains challenging to develop injectable, biocompatible, transparent, and mass-producible hydrogels with antibacterial properties. In this study, we successfully fabricated an antibacterial drug-loaded composite hydrogel, named CC45/OKG40/HS, through a Schiff base reaction between carboxymethyl chitosan (CC) and oxidized konjac glucomannan (OKG), followed by the encapsulation of stevioside-stabilized honokiol (HS) micelles. The CC45/OKG40/HS hydrogel exhibited several favorable properties, including a short gel time (<10 min), high water content (>92%), injectability, good adhesiveness, self-healing ability, and high transparency. In vitro experiments confirmed its excellent antibacterial properties, antioxidant activities, and high biocompatibility (no cytotoxicity, hemolysis ratio <5%). Furthermore, in vivo evaluation demonstrated that the CC45/OKG40/HS0.5 hydrogel accelerated wound healing by relieving inflammatory responses and enhancing re-epithelization. Given its feasibility for mass production, the findings showed that the CC45/OKG40/HS hydrogel has the potential as an advanced antibacterial wound dressing for commercial use.

Advances in the construction and application of konjac glucomannan-based delivery systems

Konjac glucomannan (KGM) has been widely used to deliver bioactive components due to its naturalness, non-toxicity, excellent biodegradability, biocompatibility, and other characteristics. This review presents an overview of konjac glucomannan as a matrix, and the types of konjac glucomannan-based delivery systems (such as hydrogels, food packaging films, microencapsulation, emulsions, nanomicelles) and their construction methods are introduced in detail. Furthermore, taking polyphenol compounds, probiotics, flavor substances, fatty acids, and other components as representatives, the applied research progress of konjac glucomannan-based delivery systems in food are summarized. Finally, the prospects for research directions in konjac glucomannan-based delivery systems are examined, thereby providing a theoretical basis for expanding the application of konjac glucomannan in other industries, such as food and medicine.

Fabrication of jamun seed starch/tamarind kernel xyloglucan bio-nanocomposite films incorporated with chitosan nanoparticles and their application on sapota (Manilkara zapota) fruits

The present work develops bio-nanocomposite packaging films by valorizing agricultural byproducts jamun seed starch (JaSS) and tamarind kernel xyloglucan (XG), and adding varying concentrations of chitosan nanoparticles (ChNPs). The blending of JaSS and XG promotes a dense polymer network in the composite films with enhanced packaging attributes. However, ChNPs incorporation significantly reduced the viscosity and dynamic moduli of the JaSS/XG film-forming solutions. The FTIR and XRD results reveal improved intermolecular interactions and crystallinity. The DSC and TGA thermograms showed improved thermal stability in the ChNP-loaded JaSS/XG films. The addition of 3 % w/w ChNPs significantly enhanced the tensile strength (20.42 MPa), elastic modulus (0.8 GPa), and contact angle (89°), along with reduced water vapor transmission rate (13.26 g/h.m2) of the JaSS/XG films. The films exhibited strong antimicrobial activity against Bacillus cereus and Escherichia coli. More interestingly, the JaSS/XG/ChNPs coating on the sapota fruits retarded the weight loss and color change up to 12 days of storage. Overall, the JaSS/XG/ChNP bio-nanocomposites are promising packaging materials.

High-strength, antifogging and antibacterial ZnO/carboxymethyl starch/chitosan film with unique "Steel Wire Mesh" structure for strawberry preservation

In this work, a multifunctional preservative film of ZnO/carboxymethyl starch/chitosan (ZnO/CMS/CS) with the unique "Steel Wire Mesh" structure is fabricated by the chemical crosslinked of ZnO NPs, CMS and CS. Unlike traditional nano-filled polymer film, the formation of the "Steel Wire Mesh" structure of ZnO/CMS/CS film is based on the synergistic effect of ZnO NPs filled CMS/CS and the coordination crosslinked between CMS/CS and Zn2+ derived from ZnO NPs. Thanks to the "Steel Wire Mesh" structure, the tensile strength and water vapor barrier of 2.5ZnO/10CMS/CS film are 2.47 and 1.73 times than that of CS film, respectively. Furthermore, the transmittance of 2.5ZnO/10CMS/CS film during antifogging test is close to 89 %, confirming its excellent antifogging effects. And the 2.5ZnO/10CMS/CS film also exhibits excellent long-acting antibacterial activity (up to 202 h), so it can maintain the freshness and appearance of strawberries at least 5 days. More importantly, the 2.5ZnO/10CMS/CS film is sensitive to humidity changes, which achieves real-time humidity monitoring of the fruit storage environment. Note that the preparation method of the film is safe, simple and environmentally friendly, and its excellent degradation performance will not bring any problems of food safety and environmental pollution.

Preparation and Characterization of Soluble Dietary Fiber Edible Packaging Films Reinforced by Nanocellulose from Navel Orange Peel Pomace

The packaging problem with petroleum-based synthetic polymers prompts the development of edible packaging films. The high value-added reuse of navel orange peel pomace, which is rich in bioactive compounds, merited more considerations. Herein, nanocellulose (ONCC) and soluble dietary fiber (OSDF) from navel orange peel pomace are firstly used to prepare dietary fiber-based edible packaging films using a simple physical blend method, and the impact of ONCC on the film's properties is analyzed. Adopting three methods in a step-by-step approach to find the best formula for edible packaging films. The results show that dietary-fiber-based edible packaging films with 4 wt.% ONCC form a network structure, and their crystallinity, maximum pyrolysis temperature, and melting temperature are improved. What's more, dietary-fiber-based edible packaging films have a wide range of potential uses in edible packaging.

Photodynamic antibacterial application of TiO2/curcumin/hydroxypropyl-cyclodextrin and its konjac glucomannan composite films

Although photodynamic therapy (PDT) has great advantages for the treatment of bacterial infections, photosensitizers (PSs) often have many disadvantages that limit their application. Improving the shortcomings of PSs and developing efficient PDT antimicrobial materials remain serious challenges. In this study, a nanocomposite drug (TiO2/curcumin/hydroxypropyl-cyclodextrin, TiO2/Cur/HPCD) was constructed and combined with konjac glucomannan to form composite films (TiO2/Cur/HPCD films, KTCHD films). The stabilities of TiO2 and Cur were improved in the presence of HPCD. The particle size of TiO2/Cur/HPCD was approximately 33.9 nm, and the addition of TiO2/Cur/HPCD enhanced the mechanical properties of the films. Furthermore, TiO2/Cur/HPCD and KTCHD films exhibited good biocompatibility and PDT antibacterial effects. The antibacterial rate of TiO2/Cur/HPCD was 74.46 % against MRSA at 500 μg/mL and 99.998 % against E. coli at 400 μg/mL, while it was adsorbed on the surface of bacteria to improve the effectiveness of the treatment. In addition, studies in mice confirmed that TiO2/Cur/HPCD and KTCHD films can treat bacterial infections and promote wound healing, with a highest wound healing rate of 84.6 % in the KTCHD-10 films + Light group on day 12. Overall, TiO2/Cur/HPCD is a promising nano-antibacterial agent and KTCHD films have the potential to be employed as antibacterial and environment-friendly trauma dressings.

Intelligent food tag: A starch-anthocyanin-based pH-sensitive electrospun nanofiber mat for real-time food freshness monitoring

A starch-based nanofiber mat was prepared for real-time monitoring of food freshness for the first time. UV-vis results showed that roselle anthocyanins (RS) conferred a wide pH sensing range on the nanofiber mat. The prepared nanofiber mats demonstrated good color visibility (total color difference value (ΔE) increased to 56.4 ± 0.7) and a reversible response (within 120 s). Scanning electron microscopy and Fourier transform infrared spectroscopy results suggested that the nanofibers had smooth surfaces without beaded fibers and that RS was well embedded into the nanofibers. The introduction of RS improved the thermal stability of the nanofibers. Color stability tests revealed that the nanofibers exhibited excellent color stability (maximum change ΔE = 1.57 ± 0.03) after 14 days of storage. Pork and shrimp freshness tests verified that the nanofibers could effectively reflect the dynamic freshness of pork and shrimp. Nontoxic, degradable and responsive characteristics make the pH-sensitive nanofiber mat a smart food label with great application potential.

Furoic acid-mediated konjac glucomannan/flaxseed gum based green biodegradable antibacterial film for Shine-Muscat grape preservation

Considering the growing threats to the environment and human health, such as plastic pollution and food spoilage, the development of naturally antibacterial food packaging materials with biodegradable capabilities has recently attracted considerable attention. This work applies the concept of green environmental protection to packaging technology, and a new type of green edible antibacterial packaging film was developed. The basic idea is to incorporate furoic acid (FA), which possesses excellent antibacterial activity, into the flaxseed gum and konjac glucomannan matrix (FK) as a filler to obtain a series of FK-FA bioactive films. This incorporation simultaneously improves the hydrophobicity and UV-barrier ability by 12.28 % and 42.87 %, respectively. Meanwhile, the diameters of the antibacterial zone of the FK-FA0.4% films (composite FK films containing 0.4 % FA) against E. coli and S. aureus increased to 38.98 mm and 36.29 mm from 24.00 mm of pure FK film, respectively. As a consequence, the grape sample sealed with FK-FA0.4% film remained edible on the 18th day of storage, while those packaged with commercial PE film and pure FK were seriously rotted and lost edible value on the 12th day, further confirming the enhanced preservation capacity. Finally, the as-prepared films were established to be biodegradable and were almost completely degraded within 25 days under simulated environmental conditions. Overall, these promising results show the potential of FK-FA films for replacing plastic packaging materials as eco-friendly edible films with prolonged shelf life for active packaging.

Pulp waste extracted reinforced powder incorporated biodegradable chitosan composite film for enhancing red grape shelf-life

Chitosan (CS) is widely used as a natural biopolymer due to its semi-crystalline structure, good film-forming properties, and easy availability. CS-based composite films are widely used in industry, particularly in the food sector as active food packaging. Despite all of these advantages, their wide range of applications are constrained by poor mechanical properties. Therefore, this work introduced refined bamboo cellulose powder (RBCP), a reinforcing material that is extracted from waste bamboo pulp and applied to CS composite films to enhance their mechanical and physicochemical properties. The chemical composition and crystallinity properties of CS composite films with RBCP addition were observed by ATR-FTIR and XRD. The homogeneous and heterogeneous surfaces of the RBCP incorporated films before biodegradation and after biodegradation (20 days) were observed by scanning electron microscopy (SEM). The increase in reinforcing RBCP materials from 0.00 to 5.00 % resulted in an increase in tensile strength for CS/RBCP films from 2.9 to 8.3 MPa. The application of the CS/RBCP/5 composite film as red grapefruit storage was also investigated, which performed much better than commercial plastic and control CS films with 92.8 and 88.6 % viability of S. aureus and E. coli bacteria. Overall achieved properties demonstrated strong potential for usage as active packaging materials to preserve and lengthen the shelf life of red grapefruits.

Etamsylate loaded oxidized Konjac glucomannan-ε-polylysine injectable hydrogels for rapid hemostasis and wound healing

Uncontrollable bleeding is a crucial factor that can lead to fatality. Therefore, the development of hemostatic dressings that enable rapid hemostasis is of utmost importance. Hydrogels with injectability, self-healing ability, and adhesiveness hold significant potential as effective hemostatic dressings. Herein, a composite hydrogel was fabricated by the oxidized Konjac glucomannan and ε-polylysine. After the encapsulation of a hemostatic drug, etamsylate, an oxidized Konjac glucomannan/ε-polylysine/etamsylate (OKGM/PL/E) composite hydrogel that possesses favorable properties including injectability, self-healing ability, tissue adhesiveness, hemocompatibility and cytocompatibility was fabricated. The OKGM/PL/E hydrogel demonstrated the ability to effectively adhere red blood cells and seal wounds, enabling rapid control of hemorrhaging. In vivo wound healing experiments confirmed the hemostatic and wound healing efficacy of the OKGM/PL/E hydrogel, highlighting its potential as a valuable hemostatic dressing.

Exopolysaccharide riclin and anthocyanin-based composite colorimetric indicator film for food freshness monitoring

Food freshness monitoring is vital to ensure food safety. Recently, packaging materials incorporating pH-sensitive films have been employed to monitor the freshness of food products in real time. The film-forming matrix of the pH-sensitive film is essential to maintain the desired physicochemical functions of the packaging. Conventional film-forming matrices, such as polyvinyl alcohol (PVA), have drawbacks of low water resistance, poor mechanical properties, and weak antioxidant ability. In this study, we successfully synthesise PVA/riclin (P/R) biodegradable polymer films to overcome these limitations. The films feature riclin, an agrobacterium-derived exopolysaccharide. The uniformly dispersed riclin conferred outstanding antioxidant activity to the PVA film and significantly improved its tensile strength and barrier properties by forming hydrogen bonds. Purple sweet potato anthocyanin (PSPA) was used as a pH indicator. The intelligent film with added PSPA provided robust surveillance of volatile ammonia and changed its color within 30 s in the pH range of 2-12. This multifunctional colorimetric film also engendered discernible color changes when the quality of shrimp deteriorated, demonstrating its great potential as an intelligent packaging material to monitor food freshness.

Development of a multifunctional food packaging for meat products by incorporating carboxylated cellulose nanocrystal and beetroot extract into sodium alginate films

Consumers' pursuit for safe meat products is challenging to develop smart food packaging with proper mechanical properties and multifunctional properties. Therefore, this work attempted to introduce carboxylated cellulose nanocrystal (C-CNC) and beetroot extract (BTE) into sodium alginate (SA) matrix films to enhance their mechanical properties and endow them with antioxidant properties and pH-responsive capacity. The rheological results showed the C-CNC and BTE were consistently dispersed in the SA matrix. The incorporation of C-CNC made the surface and cross-section of the films rough but still dense, thus significantly improving the mechanical properties of the films. The integration of BTE provided antioxidant properties and pH responsiveness without significantly changing the thermal stability of the film. The highest tensile strength (55.74 ± 4.52 MPa) and strongest antioxidant capacities were achieved for the SA-based film with BTE and 10 wt% C-CNC. Additionally, the films possessed higher UV-light barrier properties after incorporating BTE and C-CNC. More notably, the pH-responsive films discolored when TVB-N value exceeded 18.0 mg/100 g during storage of pork at 4 °C and 20 °C, respectively. Therefore, the SA-based film with enhanced mechanical and functional properties has a high potential for quality detection in smart food packaging applications.

Multi-functional konjac glucomannan/chitosan bilayer films reinforced with oregano essential oil loaded β-cyclodextrin and anthocyanins for cheese preservation

In this work, a multifunctional bilayer film was prepared by solvent casting method. Elderberry anthocyanins (EA) were incorporated into konjac glucomannan (KGM) film as the inner indicator layer (KEA). β-cyclodextrin (β-CD) loaded with oregano essential oil (OEO) inclusion complexes (β-CD@OEO) was prepared and incorporated into chitosan (CS) film as the outer hydrophobic and antibacterial layer (CS-β-CD@OEO). The impacts of β-CD@OEO on the morphological, mechanical, thermal, water vapor permeability and water resistance properties, pH sensitivity, antioxidant, and antibacterial activities of bilayer films were thoroughly evaluated. The incorporation of β-CD@OEO into bilayer films can significantly improve the mechanical properties (tensile strength (TS): 65.71 MPa and elongation at break (EB): 16.81 %), thermal stability, and water resistance (Water contact angle (WCA): 88.15°, water vapor permeability (WVP): 3.53 g mm/m² day kPa). In addition, the KEA/CS-β-CD@OEO bilayer films showed color variations in acid-base environments, which could be used as pH-responsive indicators. The KEA/CS-β-CD@OEO bilayer films also presented controlled release of OEO, good antioxidant, and antimicrobial activity, which exhibited good potential for the preservation of cheese. To sum up, KEA/CS-β-CD@OEO bilayer films have potential applications in the field of food packaging industry.

Review of Konjac Glucomannan Structure, Properties, Gelation Mechanism, and Application in Medical Biology

Konjac glucomannan (KGM) is a naturally occurring macromolecular polysaccharide that exhibits remarkable film-forming and gel-forming properties, and a high degree of biocompatibility and biodegradability. The helical structure of KGM is maintained by the acetyl group, which plays a crucial role in preserving its structural integrity. Various degradation methods, including the topological structure, can enhance the stability of KGM and improve its biological activity. Recent research has focused on modifying KGM to enhance its properties, utilizing multi-scale simulation, mechanical experiments, and biosensor research. This review presents a comprehensive overview of the structure and properties of KGM, recent advancements in non-alkali thermally irreversible gel research, and its applications in biomedical materials and related areas of research. Additionally, this review outlines prospects for future KGM research, providing valuable research ideas for follow-up experiments.

Characterizations of konjac glucomannan/curdlan edible coatings and the preservation effect on cherry tomatoes

In this study, konjac glucomannan (KGM) and curdlan were used to fabricate composite coating (KC). The coating solutions were investigated using a rheological method, and the coatings were characterized by water solubility tests, water vapor permeability (WVP), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The preservation effect of KC coating on cherry tomatoes stored at room temperature was determined. Results indicated that the curdlan addition can adjust the hydrophilicity/hydrophobicity of KGM coatings. Curdlan addition enhanced intermolecular entanglement and film-forming property. Increasing curdlan content in KC coatings significantly decreased the moisture content, dissolution and swelling ratio, and WVP. The KGM-curdlan composites behaved as high-performance coatings with good compatibility and uniformity. The K₃C₂ coating showed the best uniformity, water barrier, and thermal stability. The application of K₃C₂ coating significantly reduced the weight loss, decay loss, and delayed the decreases of firmness, soluble solids, total acid, and VC contents of cherry tomatoes. The KGM/curdlan edible coatings have promising potential for prolonging the shelf life of cherry tomatoes and applications in fruits preservation in the future.

Structure, Merits, Gel Formation, Gel Preparation and Functions of Konjac Glucomannan and Its Application in Aquatic Food Preservation

Konjac glucomannan (KGM) is a natural polysaccharide extracted from konjac tubers that has a topological structure composed of glucose and mannose. KGM can be used as a gel carrier to load active molecules in food preservation. The three-dimensional gel network structure based on KGM provides good protection for the loaded active molecules and allows for sustained release, thus enhancing the antioxidant and antimicrobial activities of these molecules. KGM loaded with various active molecules has been used in aquatic foods preservation, with great potential for different food preservation applications. This review summarizes recent advances in KGM, including: (i) structural characterization, (ii) the formation mechanism, (iii) preparation methods, (iv) functional properties and (v) the preservation of aquatic food.

Construction and application of nano ZnO/eugenol@yam starch/microcrystalline cellulose active antibacterial film

The goal of this study was to develop new biocomposite films that can better protect and prolong the shelf life of food. Here, a ZnO: eugenol@yam starch/microcrystalline cellulose (ZnO:Eu@SC) antibacterial active film was constructed. Because of the advantages of metal oxides and plant essential oils, codoping with these can effectively improve the physicochemical and functional properties of composite films. The addition of an appropriate amount of nano-ZnO improved the compactness and thermostability, reduced the moisture sensitivity, and enhanced the mechanical and barrier properties of the film. ZnO:Eu@SC exhibited good controlled release of nano-ZnO and Eu in food simulants. Nano-ZnO and Eu release was controlled by two mechanisms: diffusion (primary) and swelling (secondary). After loading Eu, the antimicrobial activity of ZnO:Eu@SC was significantly enhanced, resulting in a synergistic antibacterial effect. Z₄:Eu@SC film extended the pork shelf life by 100 % (25 °C). In humus, the ZnO:Eu@SC film was effectively degraded into fragments. Therefore, the ZnO:Eu@SC film has excellent potential in food active packaging.

Research Progress in Hemicellulose-Based Nanocomposite Film as Food Packaging

As the main component of agricultural and forestry biomass, hemicellulose has the advantages of having an abundant source, biodegradability, nontoxicity and good biocompatibility. Its application in food packaging has thus become the focus of efficient utilization of biomass resources. However, due to its special molecular structure and physical and chemical characteristics, the mechanical properties and barrier properties of hemicellulose films are not sufficient, and modification for performance enhancement is still a challenge. In the field of food packaging materials preparation, modification of hemicellulose through blending with nanofibers or nanoparticles, both inorganic and organic, has attracted research attention because this approach offers the advantages of efficient improvement in the expected properties and better cost efficiency. In this paper, the composition of hemicellulose, the classification of nanofillers and the research status of hemicellulose-based nanocomposite films are reviewed. The research progress in modification of hemicellulose by using layered silicate, inorganic nanoparticles and organic nanoparticles in food packaging is described. Challenges and outlook of research in hemicellulose-based nanocomposite film in food packaging is discussed.

Micro-structure and tensile properties of microfluidic spinning konjac glucomannan and sodium alginate composite bio-fibers regulated by shear and elongational flow: experiment and multi-scale simulation

Microfluidic spinning has been widely used to produce bio-fibers with excellent tensile performances by regulating the conformation of biological macromolecules. However, the effect of channel shapes on fiber tensile performances is unclear. In this study, bio-fibers were prepared using konjac glucomannan and sodium alginate by five channels. The micro-morphology and tensile performance of fibers were characterized and measured. Then, the dynamical behaviours of macromolecule clusters in flow fields were simulated by multi-scale numerical methods. The results show that the elongational flow with increasing extension rates produced fibers with a tensile strength of 32.34 MPa and a tensile strain of 18.72 %, which were 1.37 and 1.55 times that for a shear flow, respectively. The difference in tensile performances was attributed to the micro-morphology regulated by flow fields. The continuously increasing extension rate of flow was more effective than the shear rate or the maximum extension rate for the stretching of macromolecule clusters. We conclude that the channel shapes significantly influence flow fields, dynamical behaviours of molecule clusters, the morphology of fibers, and tensile performances. This study provides a novel numerical method and understanding of microfluidic spinning, which will promote the optimization and applications of bio-fibers.

Characterization and antibacterial behavior of an edible konjac glucomannan/soluble black tea powder hybrid film with ultraviolet absorption

In this study, a KGM/SBTP film was prepared by a blending method using KGM and a soluble black tea film (SBTP) as substrates, and its hygroscopicity, thermal properties, light barrier properties, microstructure, and bacteriostatic properties were evaluated. The results confirmed that compared with the control group, with the increase in the SBTP content, the transmittance of the film in the ultraviolet region significantly reduced, and the water barrier property and thermal stability were improved. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) results indicated that the tea polyphenols interacted with the film substrate. SEM also showed that the structure of the KGM/SBTP films was smooth and flat, and all samples showed no fracture. In addition, the KGM/SBTP mixed membrane had obvious concentration-dependent antibacterial activity. When the concentration of SBTP was 0.9%, the inhibition zones against Staphylococcus aureus and Escherichia coli were 12.30 ± 0.20 mm and 12.05 ± 0.47 mm, respectively.

Effect of a Novel Hybrid Nanocomposite of Cisplatin-Chitosan on Induced Tissue Injury as a Suggested Drug by Reducing Cisplatin Side Effects

The self-assembly of cisplatin (Cis-Pt) and chitosan nanoparticles (Cs NPs) has been synthesized and characterized successfully by different analyses and techniques, such as scanning electron microscopy, ultraviolet-visible spectrophotometry, and Fourier transform infrared spectroscopy. The efficiency of loading Cis-Pt on Cs NPs for decreasing the side effects of Cis-Pt by loading it on Cs NP surface was revealed through histopathological and physiological measurements for the liver, testis, and kidney cells. Self-assembly hybrid nanocomposite (Cis-Pt@Cs) could improve spermatogenic cells, seminiferous tubules, and Leydig cells in the interstitial tissue. Kidney examination showed intact glomeruli with a mild increase in capsular space in addition to the intact renal tubular epithelial lining, and liver findings showed improvement in dilation and congestion of the central vein besides mild dilation of blood sinusoids in addition to a mild degree of hepatocyte vacuolation. The serum levels of hepatic, renal, and testicular marker analysis were measured, where Cis-Pt increased the serum levels of alanine aminotransferase, aspartate aminotransferase activity, urea, creatinine, and decreased testosterone levels, while synthesized self-assembly appeared normalized levels. From the results, the self-assembly hybrid nanocomposite decreases and improves the side effects of Cis-Pt.