Preparation and characterization of gelatin/zein nanofiber films loaded with perillaldehyde, thymol, or ɛ-polylysine and evaluation of their effects on the preservation of chilled chicken breast

Dual-functional Zn@melanin nanoparticles for enhanced antibacterial activity and prolonged fruit preservation

Mitigating food spoilage from microbial infections remains a critical challenge in food preservation. Although Zn2+ ions are used as chemical bactericides, their use alone often requires high doses. A novel nanomaterial, Zn@MNPs, combining photothermal properties with the controlled release of Zn2+, was synthesized through a coordination of Zn2+ with melanin nanoparticles (MNPs) derived from cuttlefish ink. Zn@MNPs were capable of attaching onto the bacterial surfaces, enabling high-efficiency release of Zn2+ under mildly acidic conditions typically associated with bacterial infections. This leads to sustained antibacterial activity, causing bacterial membrane rupture and leakage of intracellular components. Incorporating Zn@MNPs into polyvinyl alcohol (PVA)-based films improved their ability to block UV light and reduce oxygen and water vapor permeability. These films effectively reduced dehydration, preserved nutritional content, and extended fruit shelf life. This study highlights the potential of Zn@MNPs-based PVA films as biodegradable, bioactive packaging materials for enhancing food preservation and safety.

Stretchable, controlled release of active substances, and biodegradable chitosan-polyvinyl alcohol hydrogel film for antibacterial and chilled meat preservation

In this study, we utilized chitosan (CS) and polyvinyl alcohol (PVA) as the hydrogel matrix to fabricate a multifunctional hydrogel packaging film through the dimethylsulfoxide/hydroxybenzotriazole activation system-mediated. Based on the evaluation of thermal stability and mechanical properties, the optimal polymerization ratio of PVA to CS was determined as 3:1. Hydrogels made of 6 % PVA and 2 % CS have excellent heat resistance and adhesion, with a remarkable breakage elongation of 754.3 %. The cross-linking of PVA, CS, and ε-PL polymers occurred through esterification and amide reactions involving -COOH, -OH, and -NH2. The incorporation of ε-PL improved the thermal stability and strain properties. In vitro antibacterial assays demonstrated that the PVA/CS@ε-PL exhibited remarkable antibacterial efficacy against Staphylococcus aureus and Pseudomonas fluorescein. The PVA/CS@ε-PL-0.144 showed controlled release of ε-PL for over 3 d and extended the shelf life of chilled chicken to 8 d. These findings suggest that PVA/CS@ε-PL-0.144 is a potential antibacterial packaging.

Functionalized Gelatin Electrospun Nanofibrous Membranes in Food Packaging: Modification Strategies for Fulfilling Evolving Functional Requirements

Gelatin, known for its excellent biocompatibility, strong aggregative properties, and low cost, has been extensively investigated as a promising material for food packaging. Among various fabrication methods, electrospinning stands out due to its simplicity, cost-effectiveness, high process controllability, and ability to produce nanofiber membranes with enhanced properties. This review provides a comprehensive overview of the sources, properties, and applications of gelatin, along with the fundamental principles of electrospinning and its applications in food packaging. Additionally, the common types of electrospinning techniques used in food packaging are also covered. In recent years, increasing research efforts have focused on gelatin-based electrospun nanofiber membranes for food packaging applications. The functionalization of electrospinning gelatin-based nanofiber membrane was realized by incorporating various active substances or combining it with other techniques, fulfilling the new requirements of food packaging. In this review, gelatin-based electrospun nanofiber membranes for food packaging applications are overviewed, with a particular emphasis on various types of modifications for the membranes aimed at meeting diverse application demands. Finally, the future perspectives and challenges in the research of gelatin-based electrospun nanofiber membranes for food packaging are discussed.

An intelligent thymol/alizarin-loaded polycaprolactone/gelatin/zein nanofibrous film with pH-responsive and antibacterial properties for shrimp freshness monitoring and preservation

Improper storage methods cause food resources to be wasted, and the development of multifunctional intelligent packaging can realize freshness monitoring and extend the shelf life. In this study, an intelligent alizarin/thymol-loaded polycaprolactone/gelatin/zein nanofibrous film was prepared and achieved the dual functions of pH-responsive and antibacterial properties. The film was fabricated using electrospun technology and characterized by SEM, FT-IR, WCA, TGA, DSC, and mechanical property tests, which had good antioxidant properties (81.40 ± 0.74 % free radical scavenging). The film could effectively inhibit the growth of Escherichia coli, Staphylococcus aureus, and Shewanella putrefaciens within 12 h and exhibited light yellow-light purple-dark purple color change at pH 2-12, with good color stability and color responsiveness to ammonia in the environment. In the shrimp application, shelf life was extended by 2 days and freshness could be monitored by the color change. This scientific research opens up new possibilities for realizing multifunctional food packaging alternatives.

Crosslinked protein-polysaccharide nanocomposite coating for pork preservation: Impact on physicochemical properties and microbial structure

Edible films are significant in prolonging the shelf life of meat products. Herein, we prepared some edible coatings (EW/TNPCSs) based on egg white/chitosan/pectin as polymer matrix, containing tannic acid-nisin composite nano-crosslinker with antibacterial-antioxidant activities. The results of preservation indicated that the prepared EW/TNPCSs reduced the water loss of chilled pork and delayed the changes of taste, texture and surface color. At the end of the 12-day storage period, the content of TVB-N and carbonyl as well as the pH of EW/TNPCS5 chilled pork decreased by 33.75 %, 96.61 % and 7.09 %, respectively, and colony count decreased by 17.71 % compared to the control. Additionally, EW/TNPCSs inhibited the richness and diversity of spoilage dominant bacteria (Myroides, Acinetobacter, etc.), which were positively regulated by physicochemical indicators such as saltiness and abundance of bacteriostatic materials-coated chilled pork. It will provide a practical basis for the application of EW/TNPCSs coatings in the preservation of chilled pork.

Shellac-based films/coatings: Progress, applications and future trends in the field of food packaging

As a natural biopolymer from the secretion of insect Laccifer Lacca, shellac shows excellent film-forming ability and safety, making it an attractive material to replace synthetic materials for food packaging. On the basis of an introduction to the structure and properties of shellac, the information on single shellac films/coatings and composite films/coatings of shellac and other bio-based materials such as proteins, polysaccharides, and lipids, including the effects of adding antimicrobial agents (i.e., natural antimicrobials, synthetic antimicrobials, and metal oxide nanoparticles) on films/coatings, was comprehensively summarized. Besides, the current application status of shellac-based films/coatings as preservation packaging for poultry products, fruits, vegetables and other food products was systematically documented. Finally, the future research directions of shellac-based films/coatings such as optimizing shellac concentrations, conducting toxicological evaluation and reducing production costs were discussed. This paper will provide guidance for a systematic understanding of the research advances on shellac-based films/coatings and possible future directions.

A novel gelatin/chitosan-based "sandwich" antibacterial nanofiber film loaded with perillaldehyde for the preservation of chilled chicken

Quality deterioration caused by microorganisms is a crucial problem in food industry. Herein, to enhance the antibacterial effect and extend the storage life of chilled chicken, a gelatin/chitosan (GC)-based "sandwich" nanofiber film was prepared by sandwiching GP2 (gelatin nanofibers loaded with 2 % (v/v) perillaldehyde) between two layers of GC nanofibers. The diameter of GP nanofibers was positively correlated with perillaldehyde concentration. However, the thermal stability of GP nanofibers was negatively correlated. The thermal degradation temperature (Tm) of GP2 was the lowest. Fortunately, GC nanofibers improved Tm of GP2 from 98.91 °C to 111.60 °C. Besides, FTIR absorption bands at 1636 and 1442 cm-1 indicated that perillaldehyde was successfully embedded. Moreover, poor water resistance of gelatin nanofibers was also improved. Specifically, benefiting from the synergy between perillaldehyde and chitosan, the shelf-life of chilled chicken was efficiently prolonged (over 10 days). Thus, this "sandwich" nanofiber film shows promise for food packaging.

Development and antimicrobial activity of composite edible films of chitosan and nisin incorporated with perilla essential oil-glycerol monolaurate emulsions

Aquatic products are highly susceptible to spoilage, and preparing composite edible film with essential oil is an effective solution. In this study, composite edible films were prepared using perilla essential oil (PEO)-glycerol monolaurate emulsions incorporated with chitosan and nisin, and the film formulation was optimized by response surface methodology. These films were applied to ready-to-eat fish balls and evaluated over a period of 12 days. The films with the highest inhibition rate against Staphylococcus aureus were acquired using a polymer composition of 6 μL/mL PEO, 18.4 μg/mL glycerol monolaurate, 14.2 mg/mL chitosan, and 11.0 μg/mL nisin. The fish balls coated with the optimal edible film showed minimal changes in appearance during storage and significantly reduced total bacterial counts and total volatile basic nitrogen compared to the control groups. This work indicated that the composite edible films containing essential oils possess ideal properties as antimicrobial packaging materials for aquatic foods.

Anthocyanin-rich grape pomace extract encapsulated in protein fibers: Colorimetric profile, in vitro release, thermal resistance, and biological activities

Red wine grape pomace is an important source of bioactive compounds with biological activities of interest. Grape pomace extract can be encapsulated in ultrafine fibers using the electrospinning technique. Encapsulation is used to increase stability and protect the phenolic compounds in the extract. In this study, zein fibers were developed for encapsulation of grape pomace extract (0 %, 5 %, 10 %, and 15 % w/w). The extract was evaluated for colorimetric profile, whereas the ultrafine zein fibers carrying the extract were assessed for morphology, loading capacity, in vitro release profile, thermal and thermogravimetric properties, thermal resistance, hydrophilicity, and antioxidant and antimicrobial activities. The grape pomace extract changed color depending on pH, ranging from pink (pH 1) to yellow (pH 13 and 14). The fibers presented a smooth and uniform structure, with diameters of approximately 450 nm and a loading capacity of up to 82 %. The membranes of ultrafine fibers demonstrated hydrophilic behavior, and the in vitro release profile was dependent on the concentration of the added extract. Furthermore, the fibers were observed thermally protect the encapsulated compounds and maintain their antioxidant and antimicrobial activities. These findings indicate that the produced material has potential applications in the development of active and intelligent packaging for the food industry.

Development of pectin/chitosan-based electrospun biomimetic nanofiber membranes loaded with dihydromyricetin inclusion complexes for wound healing application

Accidents and surgical procedures inevitably lead to wounds, presenting clinical challenges such as inflammation and microbial infections that impede the wound-healing process. This study aimed to address these challenges by developing a series of novel wound dressings known as electrospun biomimetic nanofiber membranes. These membranes were prepared using electrostatic spinning technique, incorporating hydroxypropyl-β-cyclodextrin/dihydromyricetin inclusion complexes. The prepared electrospun biomimetic nanofiber membranes exhibited randomly arranged fiber morphology with average fiber diameters ranging from 200 to 400 nm, resembling the collagen fibers in the native skin. These membranes demonstrated excellent biocompatibility, hemocompatibility, surface hydrophilicity, and wettability, while also releasing dihydromyricetin in a sustained manner. In vitro testing revealed that these membranes, loaded with hydroxypropyl-β-cyclodextrin/dihydromyricetin inclusion complexes, displayed higher antioxidant potential and inhibitory effects against Staphylococcus aureus and Escherichia coli. Furthermore, these membranes significantly reduced the M1 phenotypic transition in RAW264.7 cells, even when stimulated by lipopolysaccharides, effectively restoring M2 polarization, thereby shortening the inflammatory period. Additionally, the in vivo wound healing effects of these membranes were validated. In conclusion, this study introduces a promising nanofiber membrane with diverse biological properties that holds promise for addressing various crucial aspects of the wound-healing process.

Fabrication and characterization of Karaya gum-based films reinforced with bacterial nanocellulose stabilized valerian root extract Pickering emulsion for lamb meat preservation

A novel biodegradable film was fabricated by incorporating bacterial nanocellulose stabilized valerian root extract (VRE) Pickering emulsion into karaya gum with better antioxidant and antibacterial properties for lamb meat preservation. The valerian root extract Pickering emulsion (VPE) exhibited 98 ± 1.84 % encapsulating efficiency and excellent physical stability with an average particle size of 274.6 nm. The incorporation of VPE-5 into the film matrix increased its elongation at break (EAB), and improved water resistance and barrier properties against oxygen, water vapor, and UV light. Moreover, the antioxidant and anti-bacterial properties against S.aerous and E. coli were also improved based on VPE-5 concentration. The SEM images showed a uniform distribution of VPE-5 while FTIR and XRD revealed its compatibility with karaya gum, which improved its thermal stability. The active films showed a significant preservative effect by reducing the pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and total viable count (TVC) value of lamb meat and maintained its texture and color during the storage period of 9 days at 4 °C. These results demonstrated the inclusion of VPE-5 into Karaya gum was a promising technique and offers a great potential application as a bioactive material in food packaging.

Development and characterization of active packaging system based on zein nanofibers mat incorporated with geraniol-loaded nanoliposomes

In recent years, development of biopolymeric nanofibers as an active biodegradable packaging system has attracted specific attention. The objective of this research was to develop zein-based electrospun nanofibers (NFs) incorporated with geraniol-loaded nanoliposomes (G-loaded NLPs). Geraniol was encapsulated into NLPs with an efficiency of 79.23%. The particle size and zeta potential of G-loaded NLPs were 121.50 nm and -38.30 mV, respectively. The successful loading of geraniol in the NLPs was approved by Fourier transform infrared (FT-IR) spectroscopy. The liposomal vesicles showed spherical shapes. G-loaded NLPs were added in the zein-based electrospun NFs at three different concentrations (0.25, 0.5, and 1%w/v). All NFs samples exhibited fibrillar structure. The increase of NLPs concentration enhanced the thermal stability of the NFs. However, the crystalline structure of zein NFs did not change by the addition of G-loaded NLPs. The highest surface hydrophobicity was related to the NFs containing 1% G-loaded NLPs. The mechanical parameters of NFs depend on the concentration of NLPs. The NFs incorporated with G-loaded NLPs showed inhibition activity against four foodborne pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella typhimurium) with an inhibition zone of 4.5-22 mm. Moreover, the α-diphenyl-β-picrylhydrazyl (DPPH) scavenging activity of NFs samples was located at the range of 20%-48%. These findings represent the Efficiency of the G-loaded NLPs for use as bioactive compound in the zein-based NFs as an active packaging material.

Inhibitory Effects and Mechanisms of Perilla Essential Oil and Perillaldehyde against Chestnut Pathogen Botryosphaeria dothidea

Botryosphaeria dothidea, a notorious plant pathogen, is responsible for causing chestnut rot during postharvest storage. This research aimed to assess the antifungal properties of perilla essential oil (PEO) and perillaldehyde (PAE) against B. dothidea. PEO's and PAE's inhibitory effects on B. dothidea were investigated using an agar dilution method, a fumigation method, and an in vivo assay in chestnuts and shell buckets. Based on the results of gas chromatography-mass spectrometry, it was confirmed that the main component of PEO was elemicin. The antifungal mechanism of PEO and PAE against B. dothidea was investigated by conducting staining experiments of the fungal cell wall and cell membrane. PEO and PAE strongly inhibit the mycelial growth of B. dothidea in a dose-dependent manner. The inhibitory mechanism is mainly related to the destruction of the integrity of the fungal cell wall and plasma membrane. Notably, PEO retains its antifungal efficacy against B. dothidea in chestnuts, effectively prolonging their storage life. These findings indicate that PEO and PAE are nontoxic, eco-friendly botanical fungicides, holding promise for controlling postharvest chestnut rot.

Biopolymer-based packaging films/edible coatings functionalized with ε-polylysine: New options for food preservation

In light of the commendable advantages inherent in natural polymers such as biocompatibility, biodegradability, and cost-effectiveness, researchers are actively engaged in the development of biopolymer-based biodegradable food packaging films (BFPF). However, a notable limitation is that most biopolymers lack intrinsic antimicrobial activity, thereby restricting their efficacy in food preservation. To address this challenge, various active substances with antibacterial properties have been explored as additives to BFPF. Among these, ε-polylysine has garnered significant attention in BFPF applications owing to its outstanding antibacterial properties. This study provides a brief overview of the synthesis method and chemical properties of ε-polylysine, and comprehensively examines its impact as an additive on the properties of BFPF derived from diverse biopolymers, including polysaccharides, proteins, aliphatic polyesters, etc. Furthermore, the practical applications of various BFPF functionalized with ε-polylysine in different food preservation scenarios are summarized. The findings underscore that ε-polylysine, functioning as an antibacterial agent, not only directly enhances the antimicrobial activity of BFPF but also serves as a cross-linking agent, interacting with biopolymer molecules to influence the physical and mechanical properties of BFPF, thereby enhancing their efficacy in food preservation.

Sustainable bioactive food packaging based on electrospun zein-polycaprolactone nanofibers integrated with aster yomena extract loaded halloysite nanotubes

Compostable zein-polycaprolactone (PZ) electrospun nanofiber integrated with different concentrations of Aster yomena extract loaded halloysite nanotubes (A. yomena-HNT) as bioactive nanofibrous food packaging is reported. SEM micrographs reveal heterogeneous nanofibers. A. yomena extract used in the study showed weak antioxidant activity with AAI and TEAC values of 0.229 and 0.346. In vitro, release profile over 7 days of A. yomena indicates a controlled, sustained, and prolonged release. The prepared nanofibers were effective against both gram-positive and gram-negative bacteria. The prepared composite nanofibers were rendered biocompatible and nontoxic when subjected to WST-1 and LDH assay after incubating with NIH 3T3 mouse fibroblast cell line. PZ-15 nanofiber packaging showed the best postharvest quality preservation in Black mulberry fruits after 4 days of storage at 25 °C and 85 % Rh. Moreover, the in vitro decomposition test reveals that the fabricated nanofibers decompose in the soil and do not pose as a threat to the environment.

Preparation and characterization of zein/gelatin electrospun film loaded with ε-polylysine and gallic acid as tuna packaging system

BACKGROUND

Composite nanofiber films loaded with ε-polylysine (PL) and gallic acid (GA) were prepared using a zein/gelatin (ZG) electrospinning method to develop effective active packaging films for tuna preservation. The morphology, structure, thermal stability, hydrophobicity, antibacterial, and antioxidant properties of the films, and their application for tuna during a period of storage of 4 °C were investigated.

RESULTS

PL reduced the average diameter of ZG fibers, whereas GA increased it. The PL/GA/ZG film possessed a well distributed fiber morphology with an average diameter of 810 ± 150 nm. Fourier-transform infrared spectroscopy and X-ray diffraction results showed the physical loading of PL and GA in ZG film with the main chemical bonds and crystal structure unchanged. The addition of both PL and GA reduced hydrophobicity of the ZG film while the PL/GA/ZG film was still hydrophobic. GA enhanced its thermal stability and contributed to its antioxidant activity. PL and GA synergetically enhanced the antibacterial activity of ZG film against Shewanella putrefaciens. PL combined with GA is more suitable for modifying ZG film than GA alone. The PL/GA/ZG film effectively inhibited total viable counts, total volatile base nitrogen, fat oxidation, and texture deterioration of tuna fillets at 4 °C storage, and could extend the shelf life by 3 days.

CONCLUSIONS

The PL/GA/ZG nanofiber film demonstrated promising potential for application in the preservation of aquatic products as a new antibacterial and antioxidant food packaging. © 2023 Society of Chemical Industry.

Trends in the Incorporation of Antiseptics into Natural Polymer-Based Nanofibrous Mats

Nanofibrous materials represent a very promising form of advanced carrier systems that can be used industrially, especially in regenerative medicine as highly functional bandages, or advanced wound dressings. By incorporation of antimicrobial additives directly into the structure of the nanofiber carrier, the functionality of the layer is upgraded, depending on the final requirement-bactericidal, bacteriostatic, antiseptic, or a generally antimicrobial effect. Such highly functional nanofibrous layers can be prepared mostly by electrospinning technology from both synthetic and natural polymers. The presence of a natural polymer in the composition is very advantageous. Especially in medical applications where, due to the presence of the material close to the human body, the healing process is more efficient and without the occurrence of an unwanted inflammatory response. However, converting natural polymers into nanofibrous form, with a homogeneously distributed and stable additive, is a great challenge. Thus, a combination of natural and synthetic materials is often used. This review clearly summarizes the issue of the incorporation and effectiveness of different types of antimicrobial substances, such as nanoparticles, antibiotics, common antiseptics, or substances of natural origin, into electrospun nanofibrous layers made of mostly natural polymer materials. A section describing the problematic aspects of antimicrobial polymers is also included.

Smart antibacterial nanocellulose packaging film based on pH-stimulate responsive microcapsules synthesized by Pickering emulsion template

Spoilage results in food waste and endangers consumer health, and the smart antibacterial packaging can effectively inhibit bacterial growth and reduce food spoilage. In this study, the smart antibacterial nanocellulose packaging films were developed by adding the pH-stimulated responsive microcapsules into cellulose nanofibril (CNF) film-forming. The microcapsules were synthesized by interfacial polymerization of Pickering emulsion. Carboxylated cellulose nanocrystals as solid particles stabilized the composited oil phase to prepare the oil-in-water Pickering emulsion. The emulsion with the particle concentration of 1.25 wt% and the oil phase mass fraction of 7.5 % processes excellent stability and uniform particle size, was chosen to synthesize microcapsules. The cinnamaldehyde in the film with the addition amount of microcapsules 0.6 g burst released in the first 1 h and then slowly, and the cumulative release at pH 2.0, 4.0, 5.5 and 7.2 was 28.43 μg/cm2, 18.84 μg/cm2, 16.52 μg/cm2 and 12.89 μg/cm2, respectively. The inhibitory rate of film against both E. coli and L. monocytogenes reached 99 % at pH 4.0. The shelf life of pork packed by the film prolonged to nearly 9 d at room temperature. The developed films have the potential to be used in food packaging.

Antibacterial aroma compounds as property modifiers for electrospun biopolymer nanofibers of proteins and polysaccharides: A review

Electrospinning is one of the most promising techniques for producing biopolymer nanofibers for various applications. Proteins and polysaccharides, among other biopolymers, are attractive substrates for electrospinning due to their favorable biocompatibility and biodegradability. However, there are still challenges to improve the mechanical properties, water sensitivity and biological activity of biopolymer nanofibers. Therefore, these strategies such as polymer blending, application of cross-linking agents, the addition of nanoparticles and bioactive components, and modification of biopolymer have been developed to enhance the properties of biopolymer nanofibers. Among them, antibacterial aroma compounds (AACs) from essential oils are widely used as bioactive components and property modifiers in various biopolymer nanofibers to enhance the functionality, hydrophobicity, thermal properties, and mechanical properties of nanofibers, which depends on the electrospun strategy of AACs. This review summarizes the recently reported antimicrobial activities and applications of AACs, and compares the effects of four electrospinning strategies for encapsulating AACs on the properties and applications of nanofibers. The authors focus on the correlation of the main characteristics of these biopolymer electrospun nanofibers with the encapsulation strategy of AACs in the nanofibers. Moreover, this review also particularly emphasizes the impact of the characteristics of these nanofibers on their application field of antimicrobial materials.

Recent trends in the application of protein electrospun fibers for loading food bioactive compounds

Electrospun fibers (EFs) have emerged as promising one-dimensional materials for a myriad of research/commercial applications due to their outstanding structural and physicochemical features. Polymers of either synthetic or natural precursors are applied to design EFs as carriers for bioactive compounds. For engineering food systems, it is crucial to exploit polymers characterized by non-toxicity, non-immunogenicity, biocompatibility, slow/controllable biodegradability, and structural integrity. The unique attributes of protein-based biomaterials endow a wide diversity of desirable features to EFs for meeting the requirements of advanced food/biomedical applications. In this review paper, after an overview on electrospinning, different protein materials (plant- and animal-based) as biodegradable/biocompatible building blocks for designing EFs will be highlighted. The potential application of protein-based EFs in loading bioactive compounds with the intention to inspire interests in both academia and industry will be summarized. This review concludes with a discussion of prevailing challenges in using protein EFs for the bioactive vehicle development.

The Extraction and Impact of Essential Oils on Bioactive Films and Food Preservation, with Emphasis on Antioxidant and Antibacterial Activities-A Review

Essential oils, consisting of volatile compounds, are derived from various plant parts and possess antibacterial and antioxidant properties. Certain essential oils are utilized for medicinal purposes and can serve as natural preservatives in food products, replacing synthetic ones. This review describes how essential oils can promote the performance of bioactive films and preserve food through their antioxidant and antibacterial properties. Further, this article emphasizes the antibacterial efficacy of essential oil composite films for food preservation and analyzes their manufacturing processes. These films could be an attractive delivery strategy for improving phenolic stability in foods and the shelf-life of consumable food items. Moreover, this article presents an overview of current knowledge of the extraction of essential oils, their effects on bioactive films and food preservation, as well as the benefits and drawbacks of using them to preserve food products.

Smart Packaging Based on Polylactic Acid: The Effects of Antibacterial and Antioxidant Agents from Natural Extracts on Physical-Mechanical Properties, Colony Reduction, Perishable Food Shelf Life, and Future Prospective

Changes in consumer lifestyles have raised awareness of a variety of food options and packaging technologies. Active and smart packaging is an innovative technology that serves to enhance the safety and quality of food products like fruit, vegetables, fish, and meat. Smart packaging, as a subset of this technology, entails the integration of additives into packaging materials, thereby facilitating the preservation or extension of product quality and shelf life. This technological approach stimulates a heightened demand for safer food products with a prolonged shelf life. Active packaging predominantly relies on the utilization of natural active substances. Therefore, the combination of active substances has a significant impact on the characteristics of active packaging, particularly on polymeric blends like polylactic acid (PLA) as a matrix. Therefore, this review will summarize how the addition of natural active agents influences the performance of smart packaging through systematic analysis, providing new insights into the types of active agents on physical-mechanical properties, colony reduction, and its application in foods. Through their integration, the market for active and smart packaging systems is expected to have a bright future.

Characterisation, slow-release, and antibacterial properties of carboxymethyl chitosan/inulin hydrogel film loaded with novel antilisterial durancin GL

This paper reports the development of a hydrogel film with antibacterial activity and controlled release characteristics. Carboxymethyl chitosan (CMCS) is grafted onto durancin GL and inulin via a mediated reaction between N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. Rheology tests, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy, and lap shear tests confirmed the formation of a stable chemical cross-linking and excellent adhesion hydrogel with 4 % CMCS and 8 % inulin. The CMCS/inulin hydrogel film loaded with durancin GL appears transparent and uniform. FTIR spectroscopy results reveal the interaction mode among CMCS, inulin, durancin GL, and the hydrogel film structure. Cross-linking improved thermal stability and water-vapour barrier performance. The hydrophobicity of CMCS/inulin @Durancin GL increased under a durancin GL concentration of 0.036 g/30 mL, and the release of active substances is prolonged. In-vitro antibacterial capacity and salmon preservation experiments show that the addition of durancin GL enhanced the antibacterial activity of the hydrogel film. Therefore, CMCS/inulin@Durancin GL hydrogel films can be used as fresh-keeping packaging materials in practical applications.

Edible packaging systems for improved microbial quality of animal-derived foods and the role of emerging technologies

Animal-derived foods are susceptible to microbial spoilage due to their superior nutritional composition and high moisture content. Among the various options, edible packaging is a relatively nascent area and can effectively control microbial growth without substantially affecting the sensory and techno-functional properties. Numerous studies have evaluated the effect of edible packaging systems on the microbial quality of animal-derived foods, however, a review that specifically covers the effect of edible packaging on animal foods and summarizes the findings of these studies is missing in the literature. To fill this gap, the present review analyses the findings of the studies on animal foods published during the last five years. Studies have reported edible-packaging systems for improving microbial stability of animal foods using different biopolymers (proteins, polysaccharides, lipids, and their derivatives) and bioactive ingredients (phytochemicals, peptides, plant extracts, essential oils, and their nanoparticles, nanoemulsions or coarse emulsions). In general, nanoparticles and nanoemulsions are more effective in controlling microbial spoilage in animal foods compared to the direct addition of bioactive agents to the film matrices. Studies have reported the use of non-thermal and emerging technologies in combination with edible packaging systems for improved food safety or their use for enhancing functionality, bioactivity and characteristics of the packaging systems. Future studies should focus on developing sustainable packaging systems using widely available biopolymers and bioactive ingredients and should also consider the economic feasibility at the commercial scale.

Development of chitosan/konjac glucomannan/tragacanth gum tri-layer food packaging films incorporated with tannic acid and ε-polylysine based on mussel-inspired strategy

Constructing biodegradable food packaging with good mechanics, gas barrier and antibacterial properties to maintain food quality is still challenge. In this work, mussel-inspired bio-interface emerged as a tool for constructing functional multilayer films. Konjac glucomannan (KGM) and tragacanth gum (TG) with physical entangled network are introduced in the core layer. Cationic polypeptide ε-polylysine (ε-PLL) and chitosan (CS) producing cationic-π interaction with adjacent aromatic residues in tannic acid (TA) are introduced in the two-sided outer layer. The triple-layer film mimics the mussel adhesive bio-interface, where cationic residues in outer layers interact with negatively charged TG in the core layer. Furthermore, a series of physical tests showed excellent performance of triple-layer film with great mechanical properties (tensile strength (TS): 21.4 MPa, elongation at break (EAB): 7.9 %), UV-shielding (almost 0 % UV transmittance), thermal stability, water, and oxygen barrier (oxygen permeability (OP): 1.14 × 10^-3 g/m s Pa and water vapor permeability (WVP): 2.15 g mm/m² day kPa). In addition, the triple-layer film demonstrated advanced degradability, antimicrobial functions, and presented good moisture-proof performance for crackers, which can be potentially applied as dry food packaging.

Electrospun plant protein-based nanofibers loaded with sakacin as a promising bacteriocin source for active packaging against Listeria monocytogenes in quail breast

The main objective of this study was to fabricate nanofibers from zein incorporated with two concentrations of sakacin (9 and 18 AU/mL) with anti-Listeria properties by electrospinning technique. The efficacies of the resulting active nanofibers against L. innocua, in quail breast during 24 days of refrigerated storage (4 ± 1 °C) were evaluated. The minimum inhibitory concentration (MIC) of bacteriocin against L. innocua was approximate 9 AU/mL. Fourier-transform infrared spectra of bacteriocin-loaded nanofibers indicated characteristic peaks of zein and sakacin and that the nanofibers showed an encapsulation efficiency close to 91.5 %. The thermal stability of sakacin increased by electrospinning. Scanning electron microscopy images showed that nanofibers prepared from electrospinning zein/sakacin solutions exhibited smooth and continuous nanofibers with no defects with an average diameter between 236 and 275 nm. The presence of sakacin led to decreased contact angle properties. Nanofibers with 18 AU/mL sakacin exhibited the highest zone of inhibition of 226.14 ± 8.05 mm. The lowest L. innocua (6.1 logs CFU/cm²) growth after 24 days at 4 °C were obtained in quail breast wrapped with zein containing 18 AU/mL sakacin. The results demonstrate an outlook for the potential use of zein nanofibers containing sakacin to reduce L. innocua contamination in ready-to-eat (RTE) products.

Preparation and characterization of functionalized chitosan/polyvinyl alcohol composite films incorporated with cinnamon essential oil as an active packaging material

In this study, amphiphilic chitosan (NPCS-CA) was synthesized by grafting quaternary phosphonium salt and cholic acid onto the chain of chitosan, aiming to develop an active edible film based on NPCS-CA and polyvinyl alcohol (PVA) incorporated with cinnamon essential oil (CEO) by the casting method. The chemical structure of the chitosan derivative was characterized by FT-IR, ¹H NMR and XRD. Through the characterization of FT-IR, TGA, mechanical and barrier properties of the composite films, the optimal proportion of NPCS-CA/PVA was determined as 5/5. And, the tensile strength and elongation at break of the NPCS-CA/PVA (5/5) film with 0.4 % CEO were 20.32 MPa and 65.73 %, respectively. The results revealed that the NPCS-CA/PVA-CEO composite films exhibited an excellent ultraviolet barrier property at 200-300 nm and significantly reduced oxygen permeability, carbon dioxide permeability and water vapor permeability. Furthermore, the antibacterial property of film-forming solutions against E. coli, S. aureus, and C. lagenarium was distinctly improved with the increase of NPCS-CA/PVA proportion. And, the multifunctional films effectively extended the shelf-life of mangoes at 25 °C based on the characterization of surface changes and quality indexes. The NPCS-CA/PVA-CEO films could be developed as biocomposite food packaging material.

Influence of the Maillard Reaction on Properties of Air-Assisted Electrospun Gelatin/Zein/Glucose Nanofibers

To develop biodegradable, sustainable, and environment-friendly functional food-packaging materials, gelatin/zein/glucose nanofibers were fabricated through air-assisted electrospinning and then crosslinked by the Maillard reaction under mild conditions (60 °C and 50% relative humidity) in this study. Compared to traditional electrospinning, air-assisted electrospinning increased the yield of nanofibers by 10 times, and the average diameter from 263 nm to 664 nm, while the airflow facilitated uniform and smooth nanofiber formation. During the Maillard reaction in 0-5 days, the gelatin/zein/glucose showed no morphology change. Fourier transform infrared spectra analysis indicated that gelatin interacted with zein through hydrogen bonding and the occurrence of the Maillard reaction among the protein and glucose molecules. After four days of Maillard reaction, the nanofibers presented higher thermal stability, the most hydrophobic surface (water contact angle: 133.6°), and stiffer network structure (elastic modulus of 38.63 MPa, tensile strength of 0.85 MPa). Overall, Maillard-reaction-crosslinked gelatin/zein/glucose nanofibers showed favorable physical properties, which suggests their potential for application in food-active packaging.

Pigments of aminophenoxazinones and viridomycins produced by termite-associated Streptomyces tanashiensis BYF-112

Termite-associated Streptomyces tanashiensis BYF-112 was found as a potential source for yellow and green pigments, which were stable under the tested temperature, light and metal ions. Eight metabolites (1-8), including four new natural yellow pigments aminophenoxazinones (1-4), and two rarely iron dependent green pigments viridomycin A and F (9-10) were isolated from BYF-112 cultured in YMS and YMS treated with FeSO₄, respectively. The metabolites 2-4 displayed a significant safety performance on the normal liver cell line L-02, while the metabolite 1 showed weak cytotoxicity against the L-02 and several cancer cells. Especially, in the filter paper disc tests, the compound 1 possessed strong antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) with the zone of inhibition (ZOI) of 15.3 mm, which was equal to that of referenced levofloxacin (ZOI = 15.2 mm). And the metabolite 1 also showed moderate antibacterial activities against Micrococcus teragenus and S. aureus, with the ZOI values of 15.3 and 17.2 mm. In addition, by the minimum inhibitory concentration (MIC) assay, the compound 1 displayed potential antibacterial activities against M. teragenus, S. aureus and MRSA, with the MIC values of 12.5, 12.5, and 25.0 μg/ml, respectively. The present results indicate that BYF-112 may be a promising source for safe and bioactive pigments, which can be used for further development and industrial applications.

Chemical Composition Analysis of Atropa belladonna Grown in Iran and Evaluation of Antibacterial Properties of Extract-loaded Nanofibers

In the present work, the chemical composition of extract fractions of the Atropa belladonna plant growing in the north of Iran was investigated by HPTLC, HPLC, and GC-MS. Based on HPLC results, atropine, and scopolamine were found to be higher in the fruit and leaf extracts than in other parts of the plant. The comparative GC-MS analysis showed that diacetone alcohol, mesityl oxide, palmitic acid, and linoleic acid were the major bioactive components in the root, stem, leaf, and fruit extracts, respectively. Leaf extract showed the best antioxidant activity in the DPPH test. The antibacterial activity of fractional extracts was determined against Pseudomonas aeruginosa using the MIC method, and the fruit and leaf extracts exhibited the best antibacterial activities. The leaf extract was embedded into nanofibers by electrospinning technique, and its antibacterial activity was determined against Pseudomonas aeruginosa. The morphology and mechanical properties of the nanofibers were studied with SEM, contact angle, and tensile analysis, showing ultrafine fibers with uniform morphology.

Biopolymer Nanovehicles for Oral Delivery of Natural Anticancer Agents

Cancer is the second leading cause of death throughout the world. Nature‐inspired anticancer agents (NAAs) that are a gift of nature to humanity have been extensively utilized in the alleviation/prevention of the disease due to their numerous pharmacological activities. While the oral route is an ideal and common way of drug administration, the application of NAAs through the oral pathway has been extremely limited owing to their inherent features, e.g., poor solubility, gastrointestinal (GI) instability, and low bioavailability. With the development of nano‐driven encapsulation strategies, polymeric vehicles, especially those with natural origins, have demonstrated a potent platform, which can professionally shield versatile NAAs against GI barricades and safely deliver them to the site of action. In this review, the predicament of orally delivering NAAs and the encapsulation strategy solutions based on biopolymer matrices are summarized. Proof‐of‐concept in vitro/in vivo results are also discussed for oral delivery of these agents by various biopolymer vehicles, which can be found so far from the literature. Last but not the least, the challenges and new opportunities in the field are highlighted.

In Vitro and In Situ Characterization of Psychrotrophic Spoilage Bacteria Recovered from Chilled Chicken

Spoilage bacteria play a remarkable role in the spoilage of chilled chicken. In this paper, a total of 42 isolates belonging to 16 species of four genera were isolated from chilled chicken and displayed different characterizations of psychrotrophic spoilage. Six isolates of J7, J8, Q20, Q23, R1, and R9 with differences in proteolytic capabilities were further characterized for in situ spoilage potential evaluation. Pseudomonas lundensis J8 exhibited the strongest spoilage potential in situ, displaying a fast growth rate, increased pH velocity, high total volatile basic nitrogen, and high peptide content in the chicken samples. The volatile flavor analysis of chicken samples via electronic nose indicated that the content of characteristic odors representing spoilage, including sulfides, organic sulfide, and hydride, increased during storage. Additionally, the principle component and correlation analyses revealed that the spoilage odors produced by different species of bacteria were significantly different and positively correlated with the results of protease activity in vitro. The characteristics of spoilage bacteria in chilled chicken provided a comprehensive insight into microbial assessment during storage.

Preparation of bio-based modified starch film and analysis of preservation mechanism for sweet cherry

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Preparation of modified bio-based starch film by casting method.

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Mechanism characterization of modified bio-based starch film.

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Modified bio-based starch film has preservation effect on sweet cherry.

This study aimed to synthesize packaging films using bioactive ingredients. The composite film was prepared by blending octenyl succinate cassava starch ester (OSCS) with chitosan (CS) nano-ZnO and then adding ε-polylysine (ε-PL). The study also explored the effect of different concentrations of ε-PL on OSCS/CS/ZnO films. Fourier infrared spectroscopyand fluorescence microscopy revealed that the composite film was formed by both hydrogen bonding and a Schiff base reaction. The diffraction peaks of the original materials in X-ray diffraction disappeared after film formation, indicating good miscibility between the materials. Scanning electron microscope showed that the density of its structure increased with increasing the ε-PL content. The thermogravimetric analysis showed that the addition of ε-PL improved the thermal stability of the composite film to some extent. When used in cherry preservation, the bio-based modified starch film effectively reduced cherry decay, stem dryness, and weight loss, maintained surface color, and increased the soluble solid content.

Effect of Thymus vulgaris L. essential oil and thymol on the microbiological properties of meat and meat products: A review

Since foodborne diseases are often considered as one of the biggest public health threats worldwide, effective preservation strategies are needed to inhibit the growth of undesirable microorganisms in food commodities. Up to now, several techniques have been adopted for the production of safe and high-quality products. Although the traditional methods can improve the reliability, safety, and shelf-life of food, some of them cannot be applied without rising health concerns. Thereby, the addition of various phytochemicals has gained much attention during the last decades, especially for meat products that may be contaminated with pathogenic and spoilage organisms. Thyme (Thymus vulgaris L.), as an important medicinal and culinary herb, is a promising source of bioactive compounds that have a great impact on the microbiological stability of meat by suppressing the undesirable microflora. However, the use of these antimicrobials is still facing difficulties due to their aromatic properties and variable efficacy against targeted species. In this paper, we provide an overview on the potential effects of thyme essential oil (EO) and thymol as bio-preservative agents in meat products. Furthermore, this paper provides insights into the limitations and current challenges of the addition of EOs and their constituents to meat commodities and suggests viable solutions that can improve the applicability of these phytochemicals.

Recent Advances in Bio-Based Smart Active Packaging Materials

The shortage of oil resources is currently a global problem. The use of renewable resources instead of non-renewable ones has become a hot topic of research in the eyes of scientists. In the food industry, there is a lot of interest in bio-based smart active packaging that meets the concept of sustainability and ensures safety. The packaging has antibacterial and antioxidant properties that extend the shelf life of food. Its ability to monitor the freshness of food in real time is also beneficial to consumers’ judgement of food safety. This paper summarises the main raw materials for the preparation of bio-based smart active packaging, including proteins, polysaccharides and composite materials. The current status of the preparation method of bio-based smart active packaging and its application in food preservation is summarised. The future development trend in the field of food packaging is foreseen, so as to provide a reference for the improvement of bio-based smart active packaging materials.

Monitoring dynamic changes in chicken freshness at 4 °C and 25 °C using pH-sensitive intelligent films based on sodium alginate and purple sweet potato peel extracts

A pH-sensitive intelligent indicator film was developed and used for monitoring dynamic changes in chicken freshness at 4 °C and 25 °C by immobilizing 0.2 %-1.0 % purple sweet potato peel extracts (PPE) with sodium alginate (SA). The films presented a wide range of colors from red-pink to green-yellow at 2-13, and the films with less PPE were more sensitive to ammonia. The color of films with 0.6 % PPE changed from pink to blue when used in monitoring chicken freshness at 4 °C (5 d) and 25 °C (60 h), which corresponded to changes in total volatile base nitrogen from 5.35 (5.35) mg/100 g to 16.2 (19.9) mg/100 g. Scanning electron microscopy and X-ray diffraction revealed that PPE improved the compactness and crystallinity of SA films, while Fourier transform infrared spectroscopy revealed hydrogen bonds between SA and PPE. Compared to SA films, the water vapor and light barrier abilities of films with 0.6 % were significantly improved (P < 0.05), there was no significant effect on tensile strength (P > 0.05), and the elongation of 0.6 % PPE films (P < 0.05) was decreased. Thus, PPE can serve as an excellent indicator of intelligent films for monitoring the freshness of meat products.