Starch/tea polyphenols nanofibrous films for food packaging application: From facile construction to enhance mechanical, antioxidant and hydrophobic properties

Synergistically engineered starch-based composite films: Multifunctional platforms integrating quaternary ammonium chitosan and anthocyanins for intelligent food monitoring and sustainable packaging

This study introduces a starch-based composite film integrated with quaternary ammonium chitosan (QCS) and Lycium ruthenicum anthocyanins (LRA) via a facile casting method, designed for intelligent food packaging. The influences of varying concentrations of QCS and/or LRA on water sensitivity, mechanical attributes, UV transmittance, antioxidant capacity, antibacterial performance, and pH-responsive characteristics were meticulously examined. The optimized film demonstrated a tensile strength of ∼0.68 MPa, a contact angle of ∼123.69°, and ABTS radical scavenging efficiency exceeding 80 %. The film exhibited pH-responsive color changes from pink to green across a pH range of 2-12, alongside excellent UV-blocking and antibacterial properties. Shrimp preservation experiments revealed a 16-h shelf-life extension, coupled with real-time freshness monitoring. These findings put forward an exceedingly promising approach to the promotion of starch-based films boasting diverse functionalities in the realm of intelligent food packaging, signifying a stride in this domain.

Polylactic acid amine-sensitive colorimetric indicator film loaded with eugenol/coumarin derivatives: Towards freshness indication and shelf-life extension of chilled pork

The action of microorganisms can lead to a decrease in food freshness and cause food safety issues. Traditional packaging can only provide a certain antimicrobial effect and cannot indicate the freshness of food, which can no longer meet the needs of consumers. The preparation of intelligent packaging films with antimicrobial effects and freshness indication is an effective solution. In this study, A novel electrospun intelligent food packaging film based on polylactic acid/eugenol/coumarin derivatives (7-(diethylaMino)-2-oxo-2H-chroMene-3-carbaldehyde) has been constructed to achieve the dual functions of antimicrobial and freshness indication for chilled pork. The antimicrobial layer loads eugenol coaxially into the fiber, which could scavenge 82.92 % of DPPH free radicals and effectively inhibit the growth of Escherichia coli and Staphylococcus aureus. The freshness-indicating layer showed fluorescence responsiveness to biogenic amines. The freshness-indicating and antimicrobial fibrous bilayer film turned green in practical application to indicate that the refrigerated pork had spoiled and was effective in extending the shelf life by 4-6 days. This study demonstrated the effectiveness of the bilayer film for preservation and freshness non-destructive testing of chilled pork. It provided a theoretical basis for the general application of film.

An antioxidant composite film based on loquat seed starch incorporating resveratrol-loaded core-shell nanoparticles

A Novel bioactive food packaging film was prepared from non-grain sourced loquat seed starch (LSS) incorporated with resveratrol-loaded nanoparticles (NRs) based on a zein/pectin core-shell system, where the NRs were prepared using the anti-solvent method. The chemical constitution of the LSS was analyzed. The film was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The physical, optical, and antioxidant properties of the films were also identified. The results showed that incorporating NRs into the films significantly increased antioxidation activity, although simultaneously decreasing light transmission, water content, and elongation at break properties. Furthermore, NRs (15 %) facilitated strong hydrogen bonding interactions with the LSS matrix, improving the barrier properties and tensile strength. The resveratrol release behavior of the composite films in ethanol solutions (10 % and 95 % in water, v/v) as a food simulant was also investigated. The LSS/NRs composite film is effective in delaying unwanted oxidation during the storage of soybean oil. In conclusion, LSS could be applied as a good film-forming matrix, and LSS films containing NRs exhibit excellent physical properties and antioxidant activity, making them ideal for convenience foods containing a grease mixture of spices and grease-class packaging.

Versatile corn starch-based sustainable food packaging with enhanced antimicrobial activity and preservative properties

Biodegradable active packaging has garnered significant research interest owing to growing concerns over plastic pollution and food safety. However, current food packaging materials still suffer from drawbacks such as complex synthesis processes, high production costs, and inadequate safety performance in terms of antimicrobial resistance and biodegradability. Typically, their performance in preserving fresh food is also inferior to that of plastics. Herein, a versatile corn starch-based sustainable food packaging (DC) was proposed, utilizing natural corn starch (CS) and carboxymethyl chitosan (CMCS) as raw materials. The focus was on evaluating the mechanical properties, antioxidant properties, and antimicrobial activity, and to further explore the degradability and biocompatibility of the DC films, as well as their application in fruit preservation. The results confirmed the good water vapor barrier properties, antioxidant activity (DPPH scavenging of the DC4 film reached 98.10 ± 0.32 %), Ultraviolet (UV) resistance (more than 99.8 % absorption of both UV-A and UV-B radiation), water resistance, mechanical properties, and bacteriostatic and bactericidal effect (the DC4 film reached 99.67 ± 0.58 % against Escherichia coli and 99.83 ± 0.29 % against Staphylococcus aureus) of the DC. Meanwhile, the DC exhibited favorable biodegradability in the natural environment. Finally, fruit preservation experiments confirmed that the DC could significantly extend the shelf life of fresh fruits at room temperature. Overall, this research presented a sustainable and cost-effective biomass-derived packaging film that could replace conventional petroleum-based plastics, thereby reducing environmental pollution and showing significant potential for use in food packaging.

Fibrous membranes of poly(ethylene oxide)/Sesbania gum oxide/ε-poly(lysine): An influence on its structure

Hydrogen peroxide (H2O2) was used to modify a natural polymer, sesbania gum (SG), to prepare oxidized sesbania gum (OSG) with the aim of investigating the physicochemical properties, antimicrobial activity of polyethylene oxide (PEO), OSG, and ε-poly(lysine) (ε-PL) composite fibre membranes and their applications in fresh-cut mango preservation. The PEO/OSG/ε-PL composite fibre membranes were successfully prepared via solution blow spinning (SBS) technology. The results of a series of characterizations revealed that ε-PL was successfully loaded into the fibrous membranes, exhibited good biocompatibility, and ε-PL was better encapsulated, with the membranes. The hydrophilicity, thermal stability, mechanical properties, and flexibility of the fibrous membranes were improved, and the water vapour transmission rate was reduced with the ε-PL content. In vitro bacterial inhibition experiments revealed that PEO/OSG/ε-PL fibre membranes with more than 2 wt% added ε-PL effectively inhibited the growth of E. coli and S. aureus. Fruit preservation experiments showed that PEO/OSG/ε-PL fibre membrane could reduce weight loss, inhibit microbial growth, and delay quality deterioration of fresh-cut mango. In addition, the PEO/OSG/ε-PL fibre membrane showed high biodegradability. These results show that the PEO/OSG/ε-PL composite fibre membrane prepared by SBS has application potential as an active packaging material.

Regulation of corn starch on the properties of tremella polysaccharide-egg white protein-orange juice composite gel and its application in 3D printing

The purpose of this paper was to explore the regulation of corn starch (CS) on tremella fuciformis polysaccharide-egg white protein-orange juice (TFP-EWP-OJ) composite gel to develop a new 3D printing material. The results showed that the cylinder of TFP-EWP-OJ composite gel with 0.12 g/mL CS added had the best 3D printing structure and highest printing accuracy. This was an indication that materials with suitable viscosity, hardness, and flowability were more suitable for 3D printing. The nozzle diameter and printing speed were selected to be 1.20 mm and 35 mm/s, respectively. The TFP-EWP-OJ composite gel had greater apparent viscosity and hardness as well as weaker fluidity and a denser network structure with increasing CS concentration. This suggested that the 3D printing performance of TFP-EWP-OJ composite gel can be improved by the incorporation of CS. Furthermore, fourier transform infrared spectroscopy (FT-IR) indicated that no new covalent bonds were formed between CS and the TFP-EWP-OJ composite gel.

Starch based films and coatings for food packaging: Interactions with phenolic compounds

Biodegradable starch based films and coatings have been a research focus for food packaging. Phenolic compounds have many benefits for food and health applications. This review summarized the recent advances in the development of starch based films and coatings with added phenolic compounds and extracts. The impact of the added phenolic compounds and extracts on physicochemical, mechanical, barrier, antioxidant and antimicrobial properties of starch films and coatings were described. The starch films and coatings with added phenolics were applied in the packaging of both plant and animal based food products with increased shelf life. For intelligent packaging, anthocyanins were formulated into the starch films and coatings to reflect the degree of food freshness. Composite starch materials with the addition of nanoparticles, proteins and other polysaccharides were also formulated to improve the mechanical and biological functions of the films and coatings. Significant limitations in the studies were noted due to the lack of understanding of the nature of starch-phenolics interactions at the molecular level. Overall, optimal formulations of added phenolic compounds and extracts should be obtained to have targeted mechanical, barrier, and biological properties.

Polymeric Nanofibers via Green Electrospinning for Safe Food Engineering

Electrospun functional nanofibers enable controlled release of the loaded active ingredient and an adjustable dissolution rate. However, the widespread use of toxic organic solvents in electrospinning poses risks to human health and the environment whereas increasing production costs and complexity. This article examines the application of eco-friendly electrospinning technologies in food engineering, with a focus on water-based and melt electrospinning methods. It provides a detailed analysis of water-soluble biopolymers and synthetic polymers, highlighting their current applications and challenges in food engineering. Water-based electrospinning is proposed as a sustainable alternative, offering scalability and reduced environmental impact. This transition is essential for advancing food engineering toward more sustainable and environmentally responsible practices.

Assessing the effects of dual functional V-type cornstarch films added with kiwifruit peel extracts on preservation of fresh-cut kiwifruits: A metabolomics study

Fresh-cut fruit, with nutrition and convenience, has a broad market demand. However, its shelf life is shortened due to its tissue damage. Therefore, the development of cost-effective and eco-friendly multifunctional packaging materials to extend the shelf life of fresh-cut fruits is urgently needed. A cornstarch-based film (CS film) was successfully prepared using V-type corn starch as an ethylene scavenger and kiwifruit peel extract (KPE) as an antioxidant. The film containing 4.00 % (v/v) KPE had a DPPH radical scavenging capability of 52.1 % ± 2.4 % and ABTS radical scavenging capability of 70.4 % ± 4.4 %. The amount of ethylene harvested was 17.27 cm3 g-1. In addition, the malondialdehyde content of fresh-cut kiwifruits covered by CS film decreased by 42.82 % compared with PE film after 72 h, and the hardness increased 71.20 %. And the CS film could regulate ethylene and oxygen concentration, and extending the fresh life of kiwifruit from 3 days to 15 days. Metabolomics and transcriptomic analyses revealed that the CS film regulated ethylene self-promotion and the balance of reactive oxygen species metabolism. As a result, these reduced sugar synthesis and metabolism, which helped to maintain the freshness of fresh-cut kiwifruit. These findings can serve as a reference for developing techniques to preserve the packaging of fresh-cut fruits.

PCL/soy peptide nanofibers incorporated with riboflavin/HP-β-CD assemblies for improving fruit storage quality

In this study, we first successfully developed functionalized electrospun nanofibers (PCL/SP/ICs) loaded with Riboflavin (RF) for fruit preservation with inclusion complexes (RF/HP-β-CD, IC) formed by encapsulating RF with hydroxypropyl-β-cyclodextrin (HP-β-CD) as a core material and soy peptide-assisted polycaprolactones (PCL/SP) as an overwrap material. Compared to 1 wt% and 5 wt% IC, nanofibers implanted with 3 wt% IC had an acceptable water contact angle (87.40°), good thermal stability, and superior mechanical properties. Also, RF/HP-β-CD integration conferred antimicrobial and antioxidant capabilities to PCL/SP fiber membranes. High-performance liquid chromatography (HPLC) studies revealed that produced films of PCL/SP/ICs could continuously and controllably release RF (within 200 h), hence retarding grape degradation and decreasing mass loss rate and titratable acid content throughout an 8-day storage period. Based on these findings, electrospun nanofiber films may be useful for vitamin loading in active food packaging.

Recent advances in research on biomass-based food packaging film materials

Although traditional petroleum-based packaging materials pose environmental problems, biodegradable packaging materials have attracted extensive attention from research and industry for their environmentally friendly properties. Bio-based films, as an alternative to petroleum-based packaging films, demonstrate their significant advantages in terms of environmental friendliness and resource sustainability. This paper provides an insight into the development of biomass food packaging films such as cellulose, starch, chitosan, and gelatine, including their properties, methods of preparation (e.g., solution casting, extrusion blow molding, layer-by-layer assembly, and electrostatic spinning), and applications in food packaging. Through these preparation methods, the paper analyzes how the properties of the films can be effectively tuned and optimized to meet specific packaging needs. It was found that biomass film materials for food packaging not only possess functional properties such as antimicrobial, preservation, and indication, but also that their continued material innovation and technological improvements offer promising prospects for their use in commercial applications. These advances could help advance the global sustainable development goals, while showing great potential for improving food safety and extending shelf life. Future research will further explore new functions and applications of biomass films, providing additional solutions for environmental protection and sustainability.

Structural properties and antioxidant capacity of different aminated starch-phenolic acid conjugates

Different aminated starch (AS) [EEAS (introducing ethylenediamine into starch using cross-linking-etherification-amination method (CEA)), EPAS (introducing o-phenylenediamine using CEA), OEAS (introducing ethylenediamine using cross-linking-oxidation-amination method (COA)), and OPAS (introducing o-phenylenediamine using COA)] were synthesized. The AS-phenolic acids [gallic acid (GA), syringic acid (SA), and vanillic acid (VA)] conjugates were prepared by laccase-catalyzed reaction. The grafting efficiency of EEAS on GA, SA, and VA was 36.59%, 69.71%, and 68.85%, respectively. SA reduced the maximum depolymerization rate of EEAS. The relative crystallinity of EEAS and EPAS grafted phenolic acid increased, and their particles showed severe breakage in appearance. OEAS-phenolic acid conjugates lost its granular structure and behaved as flakes and lumps, while the surface of OPAS-phenolic acid conjugates remained smooth after grafting phenolic acid. GA increased the DPPH· scavenging efficiency of EEAS from 16.12% to 79.92%. The increased antioxidant capacity of the conjugates suggested that AS-phenolic acids conjugates have high potential for applications.

Nano/micro flexible fiber and paper-based advanced functional packaging materials

Recently, fiber-based and functional paper food packaging has garnered significant attention for its versatility, excellent performance, and potential to provide sustainable solutions to the food packaging industry. Fiber-based food packaging is characterized by its large surface area, adjustable porosity and customizability, while functional paper-based food packaging typically exhibits good mechanical strength and barrier properties. This review summarizes the latest research progress on food packaging based on fibers and functional paper. Firstly, the raw materials used for preparing fiber and functional paper, along with their physical and chemical properties and roles in food packaging, were discussed. Subsequently, the latest advancements in the application of fiber and paper materials in food packaging were introduced. This paper also discusses future research directions and potential areas for improvement in fiber and functional paper food packaging to further enhance their effectiveness in ensuring food safety, quality, and sustainability.

Electrospun gelatin/tea polyphenol@pullulan nanofibers for fast-dissolving antibacterial and antioxidant applications

Bio-based active food packaging materials have a high market demand. We use coaxial electrospinning technology to prepare core-shell structured nanofibers with sustained antibacterial and antioxidant properties. The fiber core layer was composed of gelatin and tea polyphenols, whereas tea polyphenols provide antibacterial and antioxidant properties; the fiber sheath was composed of pullulan polysaccharides with antioxidant properties. By using a scanning electron microscope, it can be seen that the diameter distribution of the prepared nanofibers was uniform and the surface is smooth; using a transmission electron microscope, it can be clearly seen that the nanofibers have a core-shell structure; Fourier Transform Infrared and X-ray diffraction analysis indicate that the nanofibers have an amorphous structure; the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging shows that nanofibers have higher antioxidant properties with the addition of tea polyphenols; antibacterial test showed that nanofibers had obvious inhibitory effect on the growth of Staphylococcus aureus and Escherichia coli; and the nanofiber film dissolution test shows that nanofibers can be used as fast soluble active packaging. Finally, core-sheath-structured nanofibers can serve as active packaging for instant food, possessing both rapid water solubility and excellent antibacterial and antioxidant activity, making water-soluble nanofibers interesting applications in the field of food packaging.

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.

Starch-chitosan-Taro mucilage nanocomposite active food packaging film doped with zinc oxide nanoparticles - Fabrication, mechanical properties, anti-bacterial activity and eco toxicity assessment

In this research, a novel active food packaging material was developed by blending starch, chitosan, and plant-based mucilage with zinc oxide nanoparticles. The polymeric nanocomposite film, created by incorporating zinc oxide nanoparticles into the mixture using a straightforward approach, was analyzed for its structural and functional attributes using FTIR, XRD, SEM, and TGA/DSC. These analyses revealed a robust interaction between the polymers' functional groups and the nanoparticles, forming a stable film. The film's mechanical properties, including tensile strength and Young's modulus, were high. It also showed reduced wettability and water solubility, enhancing water resistance. The biodegradability rate was 100 %. Antibacterial tests against Bacillus sp. and Pseudomonas sp. showed significant inhibition zones of 26 mm and 30 mm, respectively, demonstrating strong antibacterial effectiveness. The film's non-target toxicity was assessed through phytotoxicity experiments on Vigna angularis and soil nutrient evaluations, with no negative impact on plant growth or soil health observed. These results indicate that this nanocomposite is a safe, biocompatible option for food packaging.

Effects of starch filling on physicochemical properties, functional activities, and release characteristics of PBAT-based biodegradable active films loaded with tea polyphenols

In this work, the modification of poly(butylene adipate-co-terephthalate) (PBAT) was combined with the development of active packaging films. PBAT, starch, plasticizer, and tea polyphenols (TP) were compounded and extrusion-blown into thermoplastic starch (TPS)/PBAT-TP active films. Effects of TPS contents on physicochemical properties, functional activities, biodegradability, and release kinetics of PBAT-based active films were explored. Starch interacted strongly with TP through hydrogen bonding and induced the formation of heterogeneous structures in the films. With the increase in TPS contents, surface hydrophilicity and water vapor permeability of the films increased, while mechanical properties decreased. Blending starch with PBAT greatly accelerated degradation behavior of the films, and the T30P70-TP film achieved complete degradation after 180 days. As TPS contents increased, swelling degree of the films increased and TP release were improved accordingly, resulting in significantly enhanced antioxidant and antimicrobial activities. This work demonstrated that filling starch into PBAT-based active films could achieve different antioxidant and antimicrobial activities of the films by regulating film swelling and release behavior.

Structural characterization of glutaraldehyde crosslinked starch-based nanofibrous film and adsorption improvement for oyster peptide flavor

The inferior hydrophobicity and mechanical properties of starch-based nanofibrous films significantly restrict their practical application. In view of this, this study prepared octenylsuccinylated starch-pullulan nanofibrous films using electrospinning and glutaraldehyde (GTA) gas-phase crosslinking. After GTA crosslinking, the starch-based nanofibrous films remained white, randomly oriented, smooth, and droplet-free. As the crosslinking time increased from 0 h to 24 h, the mean fibrous diameter augmented from 157.34 nm to 238.66 nm, and the water contact angle rose from 24.30° to 52.49°. Meanwhile, their tensile strength and thermal stability grew, and the mean pore area and elongation at break abated with changes in function groups. The crosslinked starch-based nanofibrous films exhibited an enhanced adsorption capacity for alcohols, ethers, esters, hydrocarbons, and N-compounds of oyster peptides. Correlation analysis shows that the adsorption capacity of the starch-based nanofibrous films was positively correlated with mean fibrous diameter and water contact angle and negatively correlated with mean pore area. These results provide a theoretical basis for the practical application of crosslinked starch-based nanofibrous film materials in deodorization.

A comprehensive review on starch-based sustainable edible films loaded with bioactive components for food packaging

Biopolymers like starch, a renewable and widely available resource, are increasingly being used to fabricate the films for eco-friendly packaging solutions. Starch-based edible films offer significant advantages for food packaging, including biodegradability and the ability to extend shelf life. However, they also present challenges such as moisture sensitivity and limited barrier properties compared to synthetic materials. These limitations can be mitigated by incorporating bioactive components, such as antimicrobial agents or antioxidants, which enhance the film's resistance to moisture and improve its barrier properties, making it a more viable option for food packaging. This review explores the emerging field of starch-based sustainable edible films enhanced with bioactive components for food packaging applications. It delves into fabrication techniques, structural properties, and functional attributes, highlighting the potential of these innovative films to reduce environmental impact and preserve food quality. Key topics discussed include sustainability issues, processing methods, performance characteristics, and potential applications in the food industry. The review provides a comprehensive overview of current research and developments in starch-based edible films, presenting them as promising alternatives to conventional food packaging that can help reduce plastic waste and environmental impact.

Advances and applications of crosslinked electrospun biomacromolecular nanofibers

Electrospinning is a technology for fabricating ultrafine fibers from natural or synthetic polymers that have novel or enhanced functional properties. These fibers have found applications in a diverse range of fields, including the food, medicine, cosmetics, agriculture, and chemical industries. However, the tendency for electrospun nanofibers to dissociate when exposed to certain environmental conditions limits many of their practical applications. The structural integrity and functional attributes of these nanofibers can be improved using physical and/or chemical crosslinking methods. This review article discusses the formation of polymeric nanofibers using electrospinning and then describes how different crosslinking methods can be used to enhance their mechanical, thermal, and biological attributes. Methods for optimizing the crosslinking reactions are discussed, including proper selection of crosslinker type and reaction conditions. Then, food, medical, and separation applications of crosslinked electrospun fibers are assessed, including in bone and skin tissue engineering, wound healing, drug delivery, air filtration, water filtration, oil removal, food packaging, food preservation, and bioactive delivery. Finally, areas where future research are needed are highlighted, as well as possible future applications of crosslinked nanofibers.

Antimicrobial polysaccharide hydrogels embedded with methyl-β-cyclodextrin/thyme oil inclusion complexes for exceptional mechanical performance and chilled chicken breast preservation

While hydrogels have potential for food packaging, limited research on hydrogels with excellent mechanical performance and antibacterial activity for preserving chicken breasts. Herein, we created antibacterial hydrogels by embedding methyl-β-cyclodextrin/thyme oil inclusion complexes (MCD/TO-ICs) into a polyvinyl alcohol matrix containing dendrobium polysaccharides and guar gum in varying ratios using freeze-thaw cycling method. The resulting hydrogels exhibited a more compact structure than those without MCD/TO-ICs, enhancing thermal stability and increasing glass transition temperature due to additional intermolecular interactions between polymer chains that inhibited chain movement. XRD analysis showed no significant changes in crystalline phase, enabling formation of a 3D network through abundant hydrogen bonding. Moreover, the hydrogel demonstrated exceptional durability, with a toughness of 350 ± 25 kJ/m3 and adequate tearing resistance of 340 ± 30 J/m2, capable of lifting 3 kg weight, 1200 times greater than the hydrogel itself. Additionally, the hydrogels displayed excellent antimicrobial activity and antioxidant properties. Importantly, the hydrogels effectively maintained TVB-N levels and microbial counts within acceptable ranges, preserving sensory properties and extending the shelf life of chilled chicken breasts by four days. This study highlights the potential of MCD/TO-IC-incorporated polysaccharide hydrogels as safe and effective active packaging solutions for preserving chilled chicken in food industry.

Improving structural and functional properties of starch-catechin-based green nanofiber mats for active food packaging by electrospinning and crosslinking techniques

The hydrophilic and low mechanical properties limited the application of starch-based films. In this work, a hydrophobic starch-based nanofiber mat was first successfully prepared from aqueous solution at room temperature by using electrospinning and glutaraldehyde (GTA) vapor phase crosslinking techniques for active packaging applications. Catechin (CAT) was immobilized in the nanofibers by electrospinning, resulting in higher thermal stability (Tdmax = 315.23 °C), antioxidant (DPPH scavenging activity = 94.31 ± 2.70 %) and antimicrobial (inhibition zone diameter = 15.6 ± 0.3 mm) of the fibers, which further demonstrated hydrogen bonding and electrostatic interaction between CAT and fibers. Nanofibers after GTA vapor phase crosslinking exhibited enhanced hydrophobicity (water contact angle: 15.6 ± 1.5° → 93.5 ± 2.3°) and mechanical properties (tensile strength: 1.82 ± 0.06 MPa → 7.64 ± 0.24 MPa, elastic modulus: 19.35 ± 0.63 MPa → 45.34 ± 0.51 MPa). The results demonstrated that preparation of starch-based electrospun nanofiber mats in aqueous system at room temperature overcame the challenges of organic solvent pollution and thermosensitive material encapsulation, while GTA vapor phase crosslinking technique improved the hydrophobicity and mechanical properties of nanofiber mats, which facilitated the application of starch-based materials in the field of packaging.

Electrospun films incorporating humic substances of application interest in sustainable active food packaging

Sustainable active food packaging is essential to reduce the use of plastics, preserve food quality and minimize the environmental impact. Humic substances (HS) are rich in redox-active compounds, such as quinones, phenols, carboxyl, and hydroxyl moieties, making them functional additives for biopolymeric matrices, such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Herein, composites made by incorporating different amounts of HS into PHBV were developed using the electrospinning technology and converted into homogeneous and continuous films by a thermal post-treatment to obtain a bioactive and biodegradable layer which could be part of a multilayer food packaging solution. The morphology, thermal, optical, mechanical, antioxidant and barrier properties of the resulting PHBV-based films have been evaluated, as well as the antifungal activity against Aspergillus flavus and Candida albicans and the antimicrobial properties against both Gram (+) and Gram (-) bacterial strains. HS show great potential as natural additives for biopolymer matrices, since they confer antioxidant, antimicrobial, and antifungal properties to the resulting materials. In addition, barrier, optical and mechanical properties highlighted that the obtained films are suitable for sustainable active packaging. Therefore, the electrospinning methodology is a promising and sustainable approach to give biowaste a new life through the development of multifunctional materials suitable in the active bio-packaging.

Electrospinning and electrospun polysaccharide-based nanofiber membranes: A review

The electrospinning technology has set off a tide and given rise to the attention of a widespread range of research territories, benefiting from the enhancement of nanofibers which made a spurt of progress. Nanofibers, continuously produced via electrospinning technology, have greater specific surface area and higher porosity and play a non-substitutable key role in many fields. Combined with the degradability and compatibility of the natural structure characteristics of polysaccharides, electrospun polysaccharide nanofiber membranes gradually infiltrate into the life field to help filter air contamination particles and water pollutants, treat wounds, keep food fresh, monitor electronic equipment, etc., thus improving the life quality. Compared with the evaluation of polysaccharide-based nanofiber membranes in a specific field, this paper comprehensively summarized the existing electrospinning technology and focused on the latest research progress about the application of polysaccharide-based nanofiber in different fields, represented by starch, chitosan, and cellulose. Finally, the benefits and defects of electrospun are discussed in brief, and the prospects for broadening the application of polysaccharide nanofiber membranes are presented for the glorious expectation dedicated to the progress of the eras.

Robust design of starch composite nanofibrous films for active food packaging: Towards improved mechanical, antioxidant, and antibacterial properties

Developing efficient and biodegradable packaging films is of paramount significance owing to the scarcity of petroleum based resources. However, their applications in food packaging are limited due to their poor mechanical properties and inadequate biological activities. This study proposes a novel approach to develop the starch composite nanofibrous films (SNFs/TA/Fe3+) consisting of starch, tannic acid, and Fe3+ using the temperature-assisted electrospinning method. The addition of TA resulted in a decrease in the rate of thermal degradation, indicating an improvement in the thermal stability of SNFs. However, the incorporation of TA or TA/Fe3+ showed only a slight impact on the internal structure of SNFs. SNFs/TA/Fe3+ loaded with 0.1 wt% of Fe3+ demonstrated a significantly higher tensile strength compared to SNFs and those loaded with TA alone. The presence of TA enhances the antioxidant activity of SNFs, and the robust SNFs/TA/Fe3+ exhibited comparable antioxidant activity to SNFs/TA. However, the SNFs/TA/Fe3+ showed a reduction in antibacterial activity, possibly due to the high valence state of the metal ions. Overall, these findings highlighted that a simple electrospinning method was used to produce SNFs/TA/Fe3+ resulted in improved mechanical properties and antioxidant activity, offering a new strategy for the development of active food packaging using SNFs.

Preparation of astaxanthin-loaded composite micelles with coaxial electrospray technology for enhanced oral bioavailability and improved antioxidation capability

BACKGROUND

Astaxanthin (AST) is approved by the US Food and Drug Administration (FDA) as a safe dietary supplement for humans. As a potent lipid-soluble keto-carotenoid, it is widely used in food, cosmetics, and the pharmaceutical industry. However, its low solubility limits its powerful biological activity and its application in these fields. This study aims to develop a delivery system to address the low solubility and bioavailability of AST and to enhance its antioxidant capacity.

RESULTS

Astaxanthin-loaded composite micelles were successfully prepared via coaxial electrospray technology. Astaxanthin existed in the amorphous state in the electro-sprayed formulation with an approximate particle size of 186.28 nm and with a polydispersity index of 0.243. In this delivery system, Soluplus and copovidone (PVPVA 64) were the main polymeric matrix for AST, which then released the drug upon contact with aqueous media, resulting in an overall increase in drug solubility and a release rate of 94.08%. Meanwhile, lecithin, and Polyethylene glycol-grafted Chitosan (PEG-g-CS) could support the absorption of AST in the gastrointestinal tract, assisting transmembrane transport. The relative bioavailability reached about 308.33% and the reactive oxygen species (ROS) scavenging efficiency of the formulation was 44.10%, which was 1.57 times higher than that of free astaxanthin (28.10%) when both were at the same concentration level based on astaxanthin.

CONCLUSION

Coaxial electrospray could be applied to prepare a composite micelles system for the delivery of poorly water-soluble active ingredients in functional food, cosmetics, and medicine. © 2023 Society of Chemical Industry.

Research on topological effect of natural small molecule and high-performance antibacterial air filtration application by electrospinning

The application of natural small molecule (NSM) in electrospun fibers is the key to achieving powerful functionality and sustainable development. However, the lack of understanding regarding the mechanism for loading NSM hinders the advancement of high-performance functional fibers. This work clarified the loading mechanism of NSM in polymer solution by comparing the different behaviors of curcumin (Cur), phloretin (PL), and tea polyphenols (TP) blended ethyl cellulose (EC) solutions. We found that TP may lead to the folding of polymer chains due to its strongest hydrogen bond, which in turn promoted the dispersion of TP along the polymer chain. Therefore, TP could achieve good electrospinnability at the highest loading capacity (16 times the Cur and 4 times the PL). Finally, chitosan was introduced into EC/TP to prepare tree-like nanofibers, achieving high-performance antibacterial air filtration. The filtration efficiency for 0.3 μm NaCl particles, pressure drop, and quality factor were 99.991 %, 85.5 Pa, and 0.1089 Pa-1, respectively. The bacteriostatic rates against Escherichia coli and Staphylococcus aureus were all 99.99 %. This work will promote the application of NSM and the developments of multifunctional electrospun fibers and high-performance air filters.

The role of alginate in starch nanocrystals-stabilized Pickering emulsions: From physical stability and microstructure to rheology behavior

Sodium alginate (SA) was used as a co-stabilizer to improve the Pickering emulsions stabilized by starch nanocrystals (SNC). Compared with pure SNC, SNC/SA complexes possess better neutral wettability with the contact angle approaching to 90°, more surface negative charges, and lower oil-water interfacial tension. These properties of particles make as-prepared emulsion higher stability with the lower creaming index and average droplet size. Furthermore, the emulsion exhibited good stability against salt (0-600 mM) and pH (2.0-6.0) at higher SA concentration (1.0 wt%). Confocal laser scanning microscopy (CLSM) images proved that SNC could be effectively adsorbed at the oil-water interface with the aid of SA. Rheological analysis showed that higher content of SA resulted in improved strength and higher viscosity of emulsion system. Results from this work indicating that SA could be a useful co-stabilizer to fulfill the demands of Pickering emulsions stabilized by SNC with stable characteristics.

Sodium alginate/carboxymethyl cellulose films embedded with liposomes encapsulated green tea extract: characterization, controlled release, application

To maintain the freshness of the fruit during storage, sodium alginate/carboxymethyl cellulose films embedded with pH-senstive liposomes encapsulated green tea extract were developed (SA/CMC/TP-Lip). An orthogonal design was used to optimise the preparation of TP-Lip and SA/CMC/TP-Lip was prepared through response surface. The stability of TP-Lip structure was measured. The morphology of SA/CMC/TP-Lip was characterised by SEM, and the mechanical properties and oxidation resistance of films were measured. Special attention was paid to the pH sensitivity of TP-Lip and the improvement of film properties. The zeta potential and encapsulation rate of TP-Lip were -45.85 ± 2.13 mV and 61.45 ± 0.23%. The average release rate of TP encapsulated into TP-Lip at pH 3 was 41.08%, an increase of 23.07% over pH 6 during 12 h. SEM and FTIR showed that TP-Lip was structurally stable and had good compatibility with SA/CMC. Tensile strength was increased by 30.55% and DPPH radical scavenging capacity was increased by 7.16% with the addition of TP-Lip. SA/CMC/TP-Lip is applied to blueberries to reduce their weight loss and improve the loss of freshness of blueberries during storage. Thus, SA/CMC/TP-Lip could provide a new way to extend active packaging materials and maintain fruit freshness during storage.

Waxy maize starch incorporated (-)-epigallocatechin-3-gallate can stabilize emulsion gel and improve antioxidant activity

A food-grade emulsion gel was stabilized using waxy maize starch (WS) incorporated (-)-epigallocatechin-3-gallate (EGCG) at different ratio (from 5 % to 20 %, w/w). The microstructure, rheological behavior, physical stability and antioxidant activity of emulsion gels were investigated using confocal laser scanning microscopy (CLSM), cryo-scanning electron microscopy (cryo-SEM), and rheometer, etc. The results suggested that incorporated EGCG obviously affected the spatial configuration of WS hydrogel. The WS/EGCG hydrogels presented an excellent lipophilic capacity characterized by tightly adhering to linseed oil droplets in the emulsion gels. Moreover, the viscosity, viscoelasticity and physical stability of the emulsion gels stabilized by the WS/EGCG hydrogel matrices were significantly enhanced. The emulsion gel stabilized by the WS/EGCG hydrogel matrix (15 % EGCG) had long-term emulsifying stability because its emulsified phase volume fraction (77.14 %) remained stable for 30 days. Compared with typical natural and synthetic antioxidants in food and pharmaceutical processing, the emulsion gels stabilized by the WS/EGCG hydrogel matrices showed significant stronger DPPH (97.45 %) and ABTS•+ (97.97 %) free radical scavenging activity. These results demonstrate that WS/EGCG hydrogels can not only be used in food-grade matrix materials to stabilize emulsion gels but also improve the antioxidant activity of the emulsion gels.

Development of antioxidant and smart NH3 -sensing packaging film by incorporating bilirubin into κ-carrageenan matrix

BACKGROUND

Active and smart food packaging based on natural polymers and pH-sensitive dyes as indicators has attracted widespread attention. In the present study, an antioxidant and amine-response color indicator film was developed by incorporating bilirubin (BIL) into the κ-carrageenan (Carr) matrix.

RESULTS

It was found that the introduction of BIL had no effect on the crystal/chemical structure, water sensitivity and mechanical performance of the Carr-based films. However, the barrier properties to light and the thermal stability were significantly improved after the addition BIL. The Carr/BIL composite films exhibited excellent 1,1-diphenyl-2-picryl-hydrazyl (i.e. DPPH)/2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (i.e. ABTS) free radical scavenging abilities and color responsiveness to different concentrations of ammonia. The application assay reflected that the Carr/BIL0.0075 film was effective in delaying the oxidative deterioration of shrimp during storage and realizing the color response of its freshness through the change of b* value.

CONCLUSION

Active and smart packaging films were successfully prepared by incorporating different contents of BIL into the Carr matrix. The present study helps to further encourage the design and development of a multi-functional packaging material. © 2023 Society of Chemical Industry.

Extraction methods, physiological activities and high value applications of tea residue and its active components: a review

Tea is a traditional plant beverage originating from China as one of the most popular beverages worldwide, which has been an important companion in modern society. Nevertheless, as the waste after tea processing, tea residues from agriculture, industry and kitchen waste are discarded in large quantities, resulting in waste of resources and environmental pollution. In recent years, the comprehensive utilization of tea residue resources has attracted people's attention. The bioactive components remaining in tea residues demonstrate a variety of health benefits and can be recycled using advanced extraction processes. Furthermore, researchers have been devoted to converting tea residues into derivatives such as biosorbents, agricultural compost, and animal feeds through thermochemical techniques and biotechnology. This review summarized the chemical composition and physiological activities of bioactive components from tea residue. The extraction methods of bioactive components in tea residue were elucidated and the main high-value applications of tea residues were proposed. On this basis, the utilization of tea residues can be developed from a single way to a multi-channel or cascade way to improve its economic efficiency. Novel applications of tea residues in different fields, including food development, environmental remediation, energy production and composite materials, are of far-reaching significance. This review aims to provide new insights into developing the utilization of tea residue using a comprehensive strategy and exploring the mechanism of active components from tea residue on human health and their potential applications in different areas.HighlightsThe composition and function of tea residue active components were introduced.The extraction methods of active components from tea residue were proposed.The main high-value applications of tea residues were summarized.The current limitations and future directions of tea residue utilization were concluded.

Fabrication, performance, and potential environmental impacts of polysaccharide-based food packaging materials incorporated with phytochemicals: A review

Although food packaging preserves food's quality, it unfortunately contributes to global climate change since the considerable carbon emissions associated with its entire life cycle. Polysaccharide-based packaging materials (PPMs) are promising options to preserve foods, potentially helping the food industry reduce its carbon footprint. PPMs incorporated with phytochemicals hold promise to address this critical issue, keep food fresh and prolong the shelf life. However, phytochemicals' health benefits are impacted by their distinct chemical structures thus the phytochemicals-incorporated PPMs generally exhibit differential performances. PPMs must be thoughtfully formulated to possess adequate physicochemical properties to meet commercial standards. Given this, this review first-time provides a comprehensive review of recent advances in the fabrication of phytochemicals incorporated PPMs. The application performances of phytochemicals-incorporated PPMs for preserving foods, as well as the intelligent monitoring of food quality, are thoroughly introduced. The possible associated environmental impacts and scalability challenges for the commercial application of these PPMs are also methodically assessed. This review seeks to provide comprehensive insights into exploring new avenues to achieve a greener and safer food industry via innovative food packaging materials. This is paramount to preserve not only food shelf life but also the environment, facilitating the eco-friendly development of the food industry.

Electrospun Nanofibers for Functional Food Packaging Application

With the strengthening of the public awareness of food safety and environmental protection, functional food packaging materials have received widespread attention. Nanofibers are considered as promising packaging materials due to their unique one-dimensional structure (high aspect ratio, large specific surface area) and functional advantages. Electrospinning, as a commonly used simple and efficient method for preparing nanofibers, can obtain nanofibers with different structures such as aligned, core-shell, and porous structures by modifying the devices and adjusting the process parameters. The selection of raw materials and structural design of nanofibers can endow food packaging with different functions, including antimicrobial activity, antioxidation, ultraviolet protection, and response to pH. This paper aims to provide a comprehensive review of the application of electrospun nanofibers in functional food packaging. Advances in electrospinning technology and electrospun materials used for food packaging are introduced. Moreover, the progress and development prospects of electrospun nanofibers in functional food packaging are highlighted. Meanwhile, the application of functional packaging based on nanofibers in different foods is discussed in detail.

Composite films of sodium alginate and konjac glucomannan incorporated with tea polyphenols for food preservation

At present, food waste has become a serious issue and the use of petroleum-based food packaging films has resulted in a series of potential hazards. Therefore, more attention has been focused on the development of new food packaging materials. The polysaccharide-based composite film loaded with active substances considered to be an excellent preservative material. A novel packaging film based on sodium alginate and konjac glucomannan (SA-KGM) blended with tea polyphenols (TP) was prepared in the present study. The excellent microstructure of films was shown by atomic force microscopy (AFM). It was indicated by FTIR spectra that the components could interact with each other through hydrogen bonds, which was also confirmed by molecular docking simulation. Meanwhile, the mechanical properties, barrier property, oxidation property, antibacterial activity, and stability of the structure of the TP-SA-KGM film were significantly improved. The AFM images and results of molecular docking simulation indicated that TP could affect the cell wall of bacteria by acting with peptidoglycan. Finally, the film showed excellent preservation effects in both beef and apples, which suggested that TP-SA-KGM film could be a novel bioactive packaging material with wide application potential in food preservation.

Encapsulation of tea polyphenols into high amylose corn starch composite nanofibrous film for active antimicrobial packaging

Starch-based composite nanofibrous films loaded with tea polyphenols (TP) were successfully fabricated through electrospinning high amylose corn starch (HACS) with aid of polyvinyl alcohol (PVA), referred as HACS/PVA@TP. With the addition of 15 % TP, HACS/PVA@TP nanofibrous films exhibited enhanced mechanical properties and water vapor barrier capability, and their hydrogen bonding interactions were further evidenced. TP was slowly released from the nanofibrous film and followed Fickian diffusion mechanism, which achieved the controlled sustained release of TP. Interesting, HACS/PVA@TP nanofibrous films effectively improved antimicrobial activities against Staphylococcus aureus (S. aureus) and prolonged the shelf life of strawberry. HACS/PVA@TP nanofibrous films showed superior antibacterial function by by destroying cell wall and cytomembrane, and degrading existing DNA fragments, stimulating excessive intracellular reactive oxygen species (ROS) generation. Our study demonstrated that the functional electrospun Starch-based nanofibrous films with enhanced mechanical properties and superior antimicrobial activities were potential for the application in active food packaging and relative areas.

Properties Comparison of Oxidized and Heat Moisture Treated (HMT) Starch-Based Biodegradable Films

Starch-based biodegradable films have been studied for a long time. To improve starch properties and to increase film characteristics, starch is commonly modified. Amongst different types of starch modifications, oxidation and heat moisture treatment are interesting to explore. Unfortunately, review on these modifications for film application is rarely found, although these starch modifications provide interesting results regarding the starch and film properties. This paper aims to discuss the progress of research on oxidized and heat moisture-treated-starch for edible film application. In general, both HMT and oxidation modification on starch lead to an increase in film's tensile strength and Young's modulus, suggesting an improvement in film mechanical properties. The elongation, however, tends to decrease in oxidized starch-based film, hence more brittle film. Meanwhile, HMT tends to result in a more ductile film. The drawback of HMT film is its lower transparency, while the opposite is observed in oxidized films. The observation on WVP (water vapor permeability) of HMT starch-based film shows that the trend of WVP is not consistent. Similarly, an inconsistent trend of WVP is also found in oxidized starch films. This suggests that the WVP parameter is very sensitive to intrinsic and extrinsic factors. Starch source and its concentration in film, film thickness, RH (relative humidity) of film storage, oxidation method and its severity, plasticizer type and its concentration in film, and crystallinity value may partly play roles in determining film properties.

Sustainable Starch/Lignin Nanoparticle Composites Biofilms for Food Packaging Applications

Construction of sustainable composite biofilms from natural biopolymers are greatly promising for advanced packaging applications due to their biodegradable, biocompatible, and renewable properties. In this work, sustainable advanced food packaging films are developed by incorporating lignin nanoparticles (LNPs) as green nanofillers to starch films. This seamless combination of bio-nanofiller with biopolymer matrix is enabled by the uniform size of nanofillers and the strong interfacial hydrogen bonding. As a result, the as-prepared biocomposites exhibit enhanced mechanical properties, thermal stability, and antioxidant activity. Moreover, they also present outstanding ultraviolet (UV) irradiation shielding performance. As a proof of concept in the application of food packaging, we evaluate the effect of composite films on delaying oxidative deterioration of soybean oil. The results indicate our composite film could significantly decrease peroxide value (POV), saponification value (SV), and acid value (AV) to delay oxidation of soybean oil during storage. Overall, this work provides a simple and effective method for the preparation of starch-based films with enhanced antioxidant and barrier properties for advanced food packaging applications.

Purple red rice bran anthocyanins reduce the digestibility of rice starch by forming V-type inclusion complexes

Purple red rice bran, a by-product of the rice polishing process, contained abundant anthocyanins. However, most of them were discarded resulting in a waste of resources. This study investigated the effects of purple red rice bran anthocyanin extracts (PRRBAE) on the physicochemical properties and digestive properties of rice starch and its mechanism of action. Infrared spectroscopy and X-ray diffraction indicated that PRRBAE could interact with rice starch through non-covalent bonds to form intrahelical V-type complexes. The DPPH and ABTS⁺ assays showed that PRRBAE could confer better antioxidant activity on rice starch. In addition, the PRRBAE could increase the resistant starch content and decrease the enzyme activities by changing the tertiary and secondary structure of starch-digesting enzymes. Further, molecular docking suggested that aromatic amino acids play a key role in the interaction of starch-digesting enzymes with PRRBAE. These findings will contribute to a better understanding of the mechanism of PRRBAE reducing starch digestibility, and to the development of high value-added products and low glycemic index (GI) foods.

Organic solvent-free starch-based green electrospun nanofiber mats for curcumin encapsulation and delivery

Developing green and efficient methods for the delivery of active food substances is a sustained demand for food scientists and industries. In this work, for the first time, we prepared a curcumin (CUR)-loaded starch-based fast-dissolving nanofiber by electrospinning technology. This green nanofiber was obtained by incorporating CUR with octenyl succinic anhydride starch (OSA) and pullulan (PUL) matrix using pure water as the solvent. To overcome the poor water-solubility and bioavailability of CUR, hydroxypropyl-beta-cyclodextrin (HPβCD) was used to form inclusion complexes. Phase solubility test results showed that by introducing HPβCD, the water-solubility of CUR was obviously improved. The prepared electrospun nanofibers were systematically characterized through scanning electron microscopy (SEM), X-ray diffraction (XRD), proton nuclear magnetic resonance spectroscopy (¹H NMR), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), encapsulation efficiency testing, solubility testing and antioxidant activity testing. The results demonstrated that CUR was well encapsulated into HPβCD and OSA/PUL/CUR-HPβCD electrospun nanofibers with fine morphology and fast-dissolving character were successfully prepared. It is worth noting that the whole process and raw materials were green, suggesting that the prepared fast-dissolving nanofiber has great application potential in the food and pharmaceutical fields.

Extrusion-blown starch/PBAT biodegradable active films incorporated with high retentions of tea polyphenols and the release kinetics into food simulants

To reduce thermal degradation of tea polyphenols (TP) in final active packaging materials, poly(butylene adipate-co-terephthalate) (PBAT), starch, plasticizer, and TP were directly synthesized into masterbatches by one-pot method in this study without pre-dispersion, and then blown into active films. TP interacted with starch through hydrogen bonds, with little interaction with PBAT. Barrier properties were improved by incorporating TP into the films, whereas mechanical properties slightly decreased. Blending starch into PBAT greatly accelerated the degradation of the film. And the incorporation of TP slowed down the short-term degradation of the starch/PBAT film, but accelerated the long-term degradation. The initial total polyphenol content in the active film was positively related to the TP loading, whereas the initial retention rate remained above 95 % regardless of TP loadings. The retention rate of TP in active films decreased with storage time, but it was still above 80 % after 12 months, with a favorable stability. TP-loaded films displayed efficient antioxidant and antimicrobial activities with strong dose dependence. The release of TP into food simulants was mainly induced by random diffusion, with little effect from polymer swelling. The short-term release kinetics was well described by Fick's second law. This work has demonstrated the feasibility of TP being incorporated into the active films with high retention through high-throughput fabrication, which provides formula and technical options for the industrial development of active packaging materials.

Preparation of hydroxypropyl starch/polyvinyl alcohol composite nanofibers films and improvement of hydrophobic properties

Starch-derived edible films have great potential as biodegradable food packaging and biomedical materials, in this study, we adopted a green method to prepare starch-based composite electrospun nanofibers films. The hydroxypropyl starches (HPS) were prepared to improve native starch solubility and properties, and a series of blend solutions were prepared with different HPS/polyvinyl alcohol (PVA) weight ratios. The comparison of the properties of HPS/PVA (HPA) nanofibers with different amylose contents were evaluated, and the fibers fabricated from hydroxypropyl high amylose starch (HP-HAS) had more continuous and homogeneous morphologies compared to the other starch fibers, it was also found that the addition of HP-HAS in the film has better mechanical properties than pure PVA film. Thus, to improve the hydrophobicity of the film, the HP-HAS/PVA (HPA(H)) nanofiber was selected for the hydrophobic study by the citric acid (CA) treatment. The hydrophobic surface was formed on the HPA(H) film by CA self-assembled coating with a water contact angle changed from 30.95° up to 100.74°. This study successfully prepared the modified starch/PVA composite nanofibers and established a simple method of self-assembled hydrophobic modification to improve water stability. Therefore, this green strategy is an alternative candidate in further study for food packaging and relative areas.

Cellulose-Based Light-Management Films with Improved Properties Directly Fabricated from Green Tea

Tea polyphenols are a phenolic bioactive compound extracted from tea leaves and have been widely used as additives to prepare functional materials used in packaging, adsorption and energy fields. Nevertheless, tea polyphenols should be extracted first from the leaves before use, leading to energy consumption and the waste of tea. Therefore, completely and directly utilizing the tea leaf to fabricate novel composite materials is more attractive and meaningful. Herein, semi-transparent green-tea-based all-biomass light-management films with improved strength, a tunable haze (60–80%) and UV-shielding properties (24.23% for UVA and 4.45% for UVB) were directly manufactured from green tea by adding high-degree polymerization wood pulps to form entanglement networks. Additionally, the green-tea-based composite films can be produced on a large scale by adding green tea solution units to the existing continuous production process of pure cellulose films. Thus, a facile and feasible approach was proposed to realize the valorization of green tea by preparing green-tea-based all-biomass light-management films that have great prospects in flexible devices and energy-efficient buildings.

Mechanistic understanding of the effect of zein–chlorogenic acid interaction on the properties of electrospun nanofiber films

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The quenching of zein by chlorogenic acid is mainly static quenching.

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Hydrogen bonding and electrostatic interaction are main driving forces.

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The tensile strength of zein film with 2.0% chlorogenic acid increased by 132.44%.

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The addition of chlorogenic acid to zein films has potential as an active packaging.

The interaction mechanism between zein and chlorogenic acid (CA) and the effect of interaction on the performance of coaxial nanofiber films were investigated. The interactions between zein and CA were characterized by multiple spectroscopic methods. Ultraviolet spectrum analysis revealed the formation of a zein–CA complex. Fluorescence analysis pointed out that the quenching of zein by CA was static. FTIR and thermodynamic analyses showed that hydrogen bonds and electrostatic interactions dominated the interaction between zein and CA. Zein-based nanofiber films were successfully prepared by coaxial electrospinning. The interaction between zein and CA enhanced the mechanical properties but reduced the thermal stability of nanofiber films. The presence of CA endowed nanofiber films with antioxidant and antibacterial properties. This research provides significant insight into the effect of protein–polyphenol interactions on the properties of electrospun nanofiber films, which can be applied in the field of active packaging to improve food safety.