Smart biodegradable films based on chitosan/methylcellulose containing Phyllanthus reticulatus anthocyanin for monitoring the freshness of fish fillet

Ferulic acid-regulated anthocyanin-based intelligent film: A promising strategy to improve stability, sensitivity, and biological activity

The attractive color of anthocyanins makes them highly desirable in active intelligent food packaging. However, the poor stability has significantly restricted their applications. In this study, a novel collagen hydrolysate-chitosan-red cabbage anthocyanin-ferulic acid (CH-CS-RCA-FA) intelligent film with high stability and bioactivity was prepared. The addition of FA not only changed structural characteristics of the film, but also endowed it with functional benefits. FA cross-linked with CH-CS-RCA through hydrogen bonding, electrostatic, and hydrophobic interactions, improving mechanical properties and water resistance of the film. FA significantly enhanced the color rendering and storage stability of the film, resulting in pronounced color change in pH 7.0-8.0 range and the increase of ammonia (NH3) sensitivity of the film. Owing to high bioactivity of FA, the radical-scavenging and bacterial inhibition rates of the CH-CS-RCA-FA film were significantly higher than those of the CH-CS-RCA film. In salmon preservation, the shelf-life of salmon after CH-CS-RCA-FA coating treatment was extended from 6 d to 12 d at 4 °C. The freshness indication sensitivity of the CH-CS-RCA-FA film was higher than that of CH-CS-RCA, especially at the medium-fresh stage. Therefore, this work provides an effective idea for the optimization of anthocyanin-based intelligent packaging systems.

An intelligent bilayer film based on blue honeysuckle berries and Artemisia Sphaerocephala Krasch. Gum for Cyprinus carpio preservation and indication

The demand for extended shelf life and food safety in the food industry continues to rise. At the same time, the environmental burden of traditional plastic packaging materials is becoming increasingly serious. Therefore, in this study, an intelligent bilayer film with a pH-sensitive inner indicator film based on Artemisia Sphaerocephala Krasch. Gum (ASKG) and blue honeysuckle berries anthocyanin (BHBA), and an antimicrobial outer film composed of polyvinyl alcohol (PVA) and cinnamon essential oil (CEO) were developed. SEM cross-sectional images showed a clear interface of the bilayer films, demonstrating the successful binding of the inner and outer layers; FTIR and X-ray results showed the binding and interaction of the components. The properties of the bilayer film were significantly enhanced with the increase of BHBA content. Compared to ASKG-BHBA film, the tensile strength of the bilayer film with 18 % anthocyanins increased by 143.66 %, elongation at break increased by 60.92 %, and showed excellent water resistance as well as water vapour barrier, thermal stability, free radical scavenging activity (increased by 14.7 %), and antimicrobial activity (inhibition circle diameter increased by 53.79 % and 57.98 %, respectively). In addition, the ASKG-BHBA and bilayer films exhibited excellent UV-vis light barrier, pH sensitivity and responsiveness to ammonia vapour. Freshness tests applied to Cyprinus carpio showed that the intelligent film could monitor the fish's freshness in real time and extended the shelf life by 1 to 3 days compared to the control. According to preliminary calculations, the cost of producing the bilayer film is about 0.1499 USD/piece. The bilayer film is expected to meet the market's dual demand for food safety and environmental protection and realize a wide range of applications in fresh food preservation and quality monitoring in the future.

Methylcellulose/Chitosan bioactive films enriched with Achyranthes aspera leaves extract: An innovative approach for sustainable cosmetic face mask applications

Adapting more sustainable materials like biopolymers to limit environmental pollution has resulted in significant advancements in various fields, particularly in biological science. The present study reports the fabrication and evaluation of the physicochemical properties of Achyranthes aspera leaves (AAL) extract loaded methylcellulose (MC)/chitosan (CS) bioactive films (MAC). FTIR, SEM and XRD results suggested that the AAL extract was compatible with the MC/CS blend and evenly dispersed throughout the MC/CS matrix. Mechanical properties evidenced significant enhancements in elongation at break. Incorporation of AAL extract significantly improved the surface wettability (~22 %), water vapor permeability (~69 %), swelling behavior (~44 %) and UV light barrier capabilities of bioactive films, demonstrating their skin moisturizing capacity and ability to prevent sunburns. Bioactive films containing a higher content of AAL extract presented enhanced bacterial inhibitory activity against E. coli and S. aureus, antioxidant efficacy (~85 %) and protein denaturation inhibitory activity (~44 %) compared to control MC/CS film. In vitro cytocompatibility tests on MEF (mouse embryonic fibroblast) cells revealed the nontoxicity (>85 % cell viability) and cytocompatibility of MAC bioactive films. Thus, MAC bioactive films have great potential to be employed as an antiaging cosmetic face mask without any risk of cytotoxicity.

Açaí powder-enriched biodegradable starch films: Characterization, release in food simulants and protective effect in photodegradation system

Açaí is an important source of natural pigments with antioxidant capacity, such as anthocyanins. Among the various possibilities for its application is its incorporation into biodegradable films, which can act as carriers of these bioactive compounds. The objective of this study was to develop biodegradable films based on starch with different açaí powder concentrations (5 % and 15 %). The films were developed using the casting technique and evaluated in relation to barrier properties, physicochemical, biodegradability, release to food simulants, and protective effect against photodegradation of β-carotene. The addition of the natural antioxidant led to the development of films with greater color intensity and improved light barrier and mechanical properties (tensile strength and elongation). The retention of açaí powder in the polymer matrix was identified in the FTIR analysis through the intensification of some regions in relation to the control film. The cohesion and interaction between film:active compound showed an improvement in water-related properties, such as reduced permeability and water absorption. Furthermore, the active films showed sustained release of anthocyanins into the food simulant (maximum of 3.04 mg cyanidin 3-glycoside/100 g and 8.06 mg cyanidin 3-glycoside/100 g for films AP5% and AP15%, respectively) and better protection against photodegradation of the β-carotene solution (35-50 % retention when exposed to high light intensity). The rapid biodegradability, thermal stability, and stability at different pH may indicate potential application as packaging for foods susceptible to photodegradation.

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

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

Chemically modified filter paper with Jaman fruit extract for visual sensing of milk freshness

Developing a non-toxic, cost-effective, and user-friendly indicator for detecting milk freshness and spoilage, with potential applications in smart packaging, presents a significant challenge. In this study, we extracted natural anthocyanins (ACNs) from Jaman (Syzgium cumini) and incorporated it in to filter paper. The presence of ACNs in the extract was confirmed through UPLC-MS/MS analysis. To enhance stability and prevent leaching, the ACNs-loaded filter paper was coated with 1 % chitosan (CH). The sensor strips were thoroughly characterized using FTIR, contact angle measurements, XRD, and FE-SEM. These strips displayed a distinct and quantifiable color change from red to colorless to yellow across different pH levels. Additionally, in real-time milk spoilage detection, the sensor transitioned from light purple to colorless. The strips demonstrated reproducibility and stability, even under high temperatures and extreme pH conditions. These findings suggest that the ACNs-loaded sensor strips hold promise for use as smart packaging materials.

Preparation and Characterization of Antioxidative and pH-Sensitive Films Based on κ-Carrageenan/Carboxymethyl Cellulose Blended with Purple Cabbage Anthocyanin for Monitoring Hairtail Freshness

Developing pH-sensitive materials for real-time freshness monitoring is critical for ensuring seafood safety. In this study, pH-responsive indicator films were prepared by incorporating purple cabbage anthocyanin (PCA) into a κ-carrageenan/carboxymethyl cellulose (CA/CMC) matrix via solution casting, with PCA concentrations of 2.5%, 5.0%, 7.5%, and 10% (w/w). The films exhibited remarkable pH sensitivity, with distinct color changes across pH 2.0-11.0. Incorporating PCA enhanced film crystallinity, antioxidant properties, and opacity while reducing water vapor transmission (WVP). High PCA content resulted in rougher morphology, lowering tensile strength (TS) but improving elongation at break (EB). The indicator film had good environmental stability, and the color difference was not visible after 10 days in the dark and 4 °C conditions. The CA/CMC/PCA-10% film showed the most pronounced pH-responsive color changes, transitioning from purple to green as hairtail freshness deteriorated. This innovative approach highlights the potential of CA/CMC/PCA films as reliable, eco-friendly indicators for real-time seafood freshness monitoring, offering significant advancements in smart packaging technology.

Chitosan research progress for smart packaging applications: a literature review

The environmental crisis was brought on by composites made of synthetic materials that are not biodegradable. Eco-friendly replacement materials for non-biodegradable composites is biodegradable composites. The poisonous remnants are avoided because of how the environment breaks them down. Biodegradable polymers are quickly broken down by bacterial breakdown. Smart packaging has been created to enable consumers to comprehend food conditions in real-time due to the growth of new technologies and consumer desire for wholesome and safe foods. This review highlights and discusses the development, type, and direction of research progress of chitosan research in the application of smart packaging, using bibliometric analysis with time intervals from 2006 to 2023. In 2006, this research began to be developed with India, China, the United States, Iran, and Egypt as the five most influential countries. From the results of keyword analysis, it was found that in addition to studying the general characteristics of smart packaging, there are currently many developments related to smart packaging materials and the effect of adding other materials to the film. The keyword analysis also revealed the current trends and future directions of chitosan research in smart packaging applications, providing valuable insights for researchers and professionals.

Recent advances in chitosan-based active and intelligent packaging films incorporated with flavonoids

Biopolymer-based films are promising packaging materials to maintain food quality, reduce food waste and ensure food safety. Chitosan, a biopolymer with excellent film-forming ability, can act as the carrier for plant-derived bioactive compounds. In the past decade, several studies have reported chitosan-based films incorporated with different classes of flavonoids, including flavones, flavanones, isoflavones, flavonols, flavanols and anthocyanidins. These films, based on their functionality, can be divided into chitosan/flavonoid active packaging films and chitosan/anthocyanin (the glycosylated anthocyanidin) intelligent packaging films. This paper presents a comprehensive review on active and intelligent packaging films prepared from chitosan and different classes of flavonoids, with special attention being paid to the preparation, physical and functional properties, stabilization, and application of the films. Factors affecting the physical and functional properties of the films are summarized. In addition, the challenges for the commercial production and application of the films in active and intelligent packaging fields are discussed.

Beet Root Peel Extract as a Natural Cost-Effective pH Indicator and Food Preservative in Edible Film: Shelf Life Improvement of Cold-Stored Trout Fillet

In this study, chitosan (C)-polyvinyl alcohol (P) edible film containing bio-fabricated nanosilver particles (nAg) (as antimicrobial agent) and beetroot peel extract (BRPE) (as antioxidant agent and pH indicator) was used as spoilage indicator in cold-stored rainbow trout fillets. DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity (43.02%), reducing power (2.87), and total phenolic content (360.50 mg GAE/g) of ethanolic BRPE were higher than aqueous extract. Silver nanoparticles were biosynthesized using silver nitrate reduction by chitosan, confirmed by UV-Visible spectroscopy, optical and scanning electron microscope images, and X-ray diffraction analysis. The highest tensile strength (4.20 MPa) and elongation at break (118%) belonged to the CP-BRPE film, and the lowest water vapor permeability (2.45 10-5 g/s/m/P) was related to the CP-nAg film. Also, the lowest total viable count (6.17 log CFU/g), psychrotrophic bacteria (6.27 log CFU/g), Enterobacteriaceae (4.9 log CFU/g), pH (5.66), total volatile basic-nitrogen (TVB-N) (22.1 mg/100 g of fish), and thiobarbituric acid reactive substances (TBARS) (0.705 mg MDA/kg of fish) values of the packaged trout fillets were significantly (p ≤ 0.05) observed in CP-BRPE-gnAg treatment among the other treatments at the end of the storage period, and CP-gnAg, CP-BRPE, and CP treatments were in the next ranks, respectively. Colorimetric analysis of the used films showed that the films containing BRPE depicted color spectra of red to yellow at the same time as the spoilage symptoms initiated in the packaged fillets. It is concluded that BRPE not only increased the preservative effects of chitosan-polyvinyl alcohol film containing green silver nanoparticles but also can be considered as a natural cost-effective spoilage indicator of the rainbow trout fillets during cold storage time.

Preparation and characterization of κ-carrageenan/dextran films blended with nano-ZnO and anthocyanin for intelligent food packaging

The κ-carrageenan/microbial-originated dextran-based multifunctional intelligent packaging films, integrated with natural anthocyanins as a colorant and ZnO as an antibacterial agent, were successfully developed using a casting method. Their applicability and functionality were systematically assessed through various analytical techniques. The addition of dextran, anthocyanins, and ZnO in the films resulted in an increased tensile strength (from 13.66 ± 0.53 to 29.70 ± 1.29 MPa) and elongation at break (from 16.69 ± 1.05 % to 39.49 ± 0.73 %), and decreased water solubility (from 64.94 ± 0.34 % to 32.84 ± 1.55 %) and water vapor barrier property (from 8.29 ± 0.12 × 10-10 g/m•s•Pa to 6.92 ± 0.1 × 10-10 g/m•s•Pa). Spectroscopic analysis revealed that the dextran, ZnO and anthocyanins were uniformly dispersed within the film-forming substrates, achieved through hydrogen bonds and electrostatic interactions. The addition of anthocyanins and ZnO not only enhanced the antibacterial and antioxidant properties of the film but also provided it with good pH sensitivity and color stability, making it highly promising for use in shrimp freshness monitoring. All the films were shown to be biodegradable, decomposing completely in soil within 30 days. Overall, these results suggest that the films could serve as a potential replacement for plastic food packaging and additionally monitor the freshness of food.

Eco-friendly methylcellulose/zinc alginate film with multi-function properties: thermal stability, flame retardancy and antibacterial activities

The purpose of this study was to synthesize crosslinked films from methylcellulose (MC) and sodium alginate (SA) using a straightforward ion exchange technique in a ZnCl2 coagulation bath. The resulting MC/ZA blend films exhibited significant improvements in thermal stability, with a measured increase of 191 °C in degradation temperature compared to MC film. The introduction of zinc ion (Zn2+) enhanced the flame retardancy of MC/ZA film, achieving a 92.4 % reduction in flammability. The microstructure of the MC/ZA blend film displayed a relatively smooth surface, indicating better biocompatibility between MC and ZA. Additionally, the barrier property of the MC/ZA film was improved, with a 35 % reduction in permeability to water vapor, and the mechanical properties were strengthened, showing a slightly reduction of 5 % in tensile strength. Furthermore, the MC/ZA blend film demonstrated enhanced antibacterial effectiveness, with a 99.99 % of S. aureus and E. coli, implying their suitability for packaging applications involving high oil content foods.

Fast and sustainable production of smart nanofiber mats by solution blow spinning for food quality monitoring: Potential of polycaprolactone and agri-food residue-derived anthocyanins

The shelf life of perishable foods is estimated through expensive and imprecise analyses that do not account for improper storage. Smart packaging, obtained by agile manufacturing of nanofibers functionalized with natural pigments from agri-food residues, presents promising potential for real-time food quality monitoring. This study employed the solution blow spinning (SBS) technique for the rapid production of smart nanofiber mats based on polycaprolactone (PCL), incorporating extracts of agricultural residues rich in anthocyanins from eggplant (EE) or purple cabbage (CE) for monitoring food quality. The addition of EE or CE to the PCL matrix increased the viscosity of the solution and the diameter of the nanofibers from 156 nm to 261-370 nm. The addition of extracts also improved the mechanical and water-related properties of the nanofibers, although it reduced the thermal stability. Attenuated total reflectance Fourier-transform infrared spectroscopy confirmed the incorporation of anthocyanins into PCL nanofibers. Nanofiber mats incorporated with EE or CE exhibited visible color changes (ΔE ≥ 3) in response to buffer solutions (pH between 3 and 10), and ammonia vapor. Smart nanofibers have demonstrated the ability to monitor fish fillet spoilage through visible color changes (ΔE ≥ 3) during storage. Consequently, smart nanofibers produced by the SBS technique, using PCL and anthocyanins from agro-industrial waste, reveal potential as smart packaging materials for food.

Synergistic berberine chloride and Curcumin-Loaded nanofiber therapies against Methicillin-Resistant Staphylococcus aureus Infection: Augmented immune and inflammatory responses in zebrafish wound healing

BACKGROUND

Wound healing pivots on a finely orchestrated inflammatory cascade, critical for tissue repair. Chronic wounds, compounded by persistent inflammation and susceptibility to infection, pose formidable clinical challenges. Nanofiber dressings offer promising avenues for wound care, yet their interaction with inflammation and infection remains elusive. We aim to delineate the inflammatory cascade preceding wound closure and assess Cu@Bbc nanofibers' therapeutic efficacy in mitigating inflammation and combating infection. Their unique attributes suggest promise in modulating inflammation, fostering tissue regeneration, and preventing microbial colonization. Investigating the intricate interplay between nanofiber scaffolds, inflammation, and infection may unveil mechanisms of enhanced wound healing. Our findings could stimulate the development of tailored dressings, urgently needed for effective wound management amidst immune dysregulation, infection, and inflammation.

METHODS

In this investigation, we synthesized Cu@Bbc nanofibers, incorporating curcumin and berberine chloride, for wound healing applications. We evaluated their individual and combined antibacterial, anti-biofilm, and antioxidant activities, alongside binding affinity with pro-inflammatory cytokines through molecular docking. Morphological characterization was conducted via SEM, FTIR assessed functional groups, and wettability contact angle measured hydrophobic properties. The physical properties, including tensile strength, swelling behavior, and thermal stability, were evaluated using tensile testing, saline immersion method and thermogravimetric analysis. Biodegradability of the nanofibers was assessed through a soil burial test. Biocompatibility was determined via MTT assay, while wound healing efficacy was assessed with in vitro scratch assays. Controlled drug release and antibacterial activity against MRSA were examined, with in vivo assessment in a zebrafish model elucidating inflammatory responses and tissue remodeling.

RESULTS

In this study, the synergistic action of curcumin and berberine chloride exhibited potent antibacterial efficacy against MRSA, with significant anti-mature biofilm disruption. Additionally, the combination demonstrated heightened antioxidant potential. Molecular docking studies revealed strong binding affinity with pro-inflammatory cytokines, suggesting a role in expediting the inflammatory response crucial for wound healing. Morphological analysis confirmed nanofiber quality, with drug presence verified via FTIR spectroscopy. Cu@Bbc demonstrated higher tensile strength, optimal swelling behavior, and robust thermal stability as evaluated through tensile testing and thermogravimetric analysis. Additionally, the Cu@Bbc nanofiber showed enhanced biodegradability, as confirmed by the soil burial test. Biocompatibility assessments showed favorable compatibility, while in vitro studies demonstrated potent antibacterial activity. In vivo zebrafish experiments revealed accelerated wound closure, re-epithelialization, and heightened immune response, indicative of enhanced wound healing.

CONCLUSION

In summary, our investigation highlights the efficacy of Cu@Bbc nanofibers, laden with curcumin and berberine chloride, in displaying robust antibacterial and antioxidant attributes while also modulating immune responses and inflammatory cascades essential for wound healing. These results signify their potential as multifaceted wound dressings for clinical implementation.

Development of carboxymethyl cellulose/starch films enriched with ZnO-NPs and anthocyanins for antimicrobial and pH-indicating food packaging

Active packaging, which can monitor food freshness and extend the shelf life, has gained significant attention in recent years. This study aims to develop a novel carboxymethyl cellulose (CMC)/starch/anthocyanins/ZnO active films with enhanced properties and specific functionalities. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that the addition of anthocyanins and nano-ZnO particles (ZnO-NPs) led to heterogeneous microstructures and a slight decrease in the crystallinity. Fourier transform infrared spectroscopy (FTIR) indicated that there were no chemical interactions among film components. Active films containing ZnO-NPs exhibited improved ductility, as well as enhanced light barrier and water resistance properties. Notably, a shift from hydrophilic to hydrophobic behavior of the films was observed with high ZnO-NP content, as evidenced by a significant increase in the water contact angle (from 63.44° to 114.22°). Furthermore, the presence of only 1 % ZnO-NPs resulted in efficient inhibition of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) growth. Moreover, active films containing both anthocyanins and ZnO-NPs were highly sensitive to pH changes in buffer solutions (pH 2-11). Based on the results, a recommended film formulation for future active packaging applications is a 80:20 CMC/starch blend with 3 % ZnO-NPs and 0.1 g anthocyanins.

Carrageenan-based sustainable biomaterials for intelligent food packaging: A review

This article explores the use of carrageenan-based biomaterials in developing sustainable and efficient intelligent food packaging solutions. The research in this field has seen a notable surge, evident from >1000 entries in databases such as Web of Science, PubMed and Science Direct between 2018 and 2023. Various film preparation techniques are explored, including solvent casting, layer-by-layer (LbL) assembly, and electrospinning. Solvent casting is commonly used to incorporate active compounds, while LbL assembly and electrospinning are favored for enhancing mechanical properties and solubility. Carrageenan's film-forming characteristics enable the production of transparent films, ideal for indicator films that facilitate visual inspection for color changes indicative of pH variations, crucial for detecting food spoilage. Surface properties can be modified using additives like plant extracts to regulate moisture interaction, affecting shelf life and food safety. These materials' antioxidant and antimicrobial attributes are highlighted, demonstrating their efficacy against pathogens such as E. coli.

Intelligent Packaging Systems with Anthocyanin: Influence of Different Polymers and Storage Conditions

With the aim of meeting the growing demand for safe food, intelligent packaging has emerged, which monitors the conditions of the food and informs the consumer about its quality directly at the time of purchase. Among intelligent packaging options, colorimetric indicator films, which change color in response to changes in the food, such as the release of volatile compounds, have been widely studied. Among them, pH indicator films composed of dyes sensitive to small variations in the pH value of the food surface have received greater attention in recent years. Anthocyanins, which are natural pigments, have stood out as one of the most commonly used sources of dyes in the production of these indicator films. In this context, the present review aims to present an updated overview of research employing anthocyanins in indicator films, including their stability under different storage conditions, the influence of different polymers used in their production, and alternative techniques for maintaining stability.

Gellan gum and pullulan-based films with triple functionalities of antioxidant, antibacterial and freshness indication properties for food packaging

The objective of this research was to fabricate pH-responsive and active films based on gellan gum (GG) and pullulan (PL) with extracts of Broussonetia papyrifera fruits (BPFE) and leaves (BPLE) by a casting method. Results indicated that the extracts had good compatibility with GG and PL, which were uniformly distributed throughout the matrix. The incorporation of BPFE and BPLE increased the thickness, UV-vis barrier property, mechanical strength, thermal stability and moisture content of the films, while decreasing the water contact angle. Notably, the films exhibited enhanced antioxidant properties, with maximum radical scavenging rates of 77.45 % using 2,2 Diphenyl-1-picrylhydrazyl and 66.21 % using 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid). The antibacterial capability of the films also increased significantly after adding BPLE and BPFE. The results of XRD and FTIR showed that BPFE was bound to GG and PL by hydrogen bond. The release behavior of BPFE from the films agreed best with the first-level kinetic model. Furthermore, the films displayed obvious color responses to ammonia gas and different pH environments. Simultaneously, the films were applied to monitor the freshness of Pelteobagrus fulvidraco fish. The color parameters of the films demonstrated high correlations with the freshness indexes measured through standard laboratory procedures.

Green synthesized CeO2 nanoparticles-based chitosan/PVA composite films: Enhanced antimicrobial activities and mechanical properties for edible berry tomato preservation

The current study is intended to enhance unique bioactive and eco-friendly composite films following a simple solvent-casting approach by incorporating cerium oxide nanoparticles (CeO2 NPs) with a chitosan (CS)/polyvinyl alcohol (PVA) matrix. Antimicrobial activity, preservation impact, mechanisms for the edible berry tomatoes and physicochemical properties of the produced films were tested. FTIR, SEM-EDX, XRD, UV-vis spectroscopy and contact angle were used to characterize the films. Incorporated (3.0 wt%) CeO2 NPs practically developed composite film's thermal stability, structural, mechanical, bioactive, antioxidant, barrier and wettability properties. The tomatoes' look, weight loss and stiffness were better preserved after 25 days of storage at room temperature (25 ± 5 °C) when 3.0 wt% CeO2 NPs films were used instead of the original CS/PVA film. CS and CeO2 NPs have unique physiochemical and antibacterial properties. Food packaging extensively investigates the modified films as antimicrobials and preservatives to increase the shelf life of packaged foods, owing to their ability to inhibit gram-positive bacteria (Bacillus cereus and Staphylococcus aureus), gram-negative bacteria (Klebsiella pneumoniae and Pseudomonas aeruginosa), and filamentous fungi (Bipolaris sorokiniana, Fusarium op., and Alternaria sp.). Our findings indicated that the CeO2/CS/PVA composite films could be used as effective wrapping materials for food preservation.

Recent advancements in chitosan-based intelligent food freshness indicators: Categorization, advantages, and applications

With an increasing emphasis on food safety and public health, there is an ongoing effort to develop reliable, non-invasive methods to assess the freshness of diverse food products. Chitosan-based food freshness indicators, leveraging properties such as biocompatibility, biodegradability, non-toxicity, and high stability, offer an innovative approach for real-time monitoring of food quality during storage and transportation. This review introduces intelligent food freshness indicators, specifically those utilizing pH-sensitive dyes like anthocyanins, curcumin, alizarin, shikonin, and betacyanin. It highlights the benefits of chitosan-based intelligent food freshness indicators, emphasizing improvements in barrier and mechanical properties, antibacterial activity, and composite film solubility. The application of these indicators in the food industry is then explored, alongside a concise overview of chitosan's limitations. The paper concludes by discussing the challenges and potential areas for future research in the development of intelligent food freshness indicators using chitosan. Thus, chitosan-based smart food preservation indicators represent an innovative approach to providing real-time data for monitoring food quality, offering valuable insights to both customers and retailers, and playing a pivotal role in advancing the food industry.

Intelligent double-layer film based on gellan gum/modified anthocyanin/curcumin/sodium alginate/zinc oxide for monitoring shrimp freshness

In this study, intelligent double-layer films were prepared using modified black rice anthocyanin (MBRA)-curcumin (CUR)-gellan gum (GG) as the inner indicator layer and sodium alginate (ALG)‑zinc oxide (ZnO) as the outer antimicrobial layer. The bilayer films were successfully prepared, as revealed by scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction measurements. The mechanical characteristics, moisture content, and water vapor resistance of GG-MBRA/CUR1@ALG-ZnO, GG-MBRA/CUR2@ALG-ZnO, and GG-MBRA/CUR3@ALG-ZnO films showed significant enhancement compared to GG-MBRA/CUR3 and ALG-ZnO films. The bilayer films exhibited excellent pH responsiveness and reacted effectively to ammonia. The outer layer significantly improved the antioxidant and antibacterial properties of the inner layer. When the films were applied to shrimp, it was found that the double-layer films not only monitored the freshness of the shrimp in real-time but also were influential in extending the shelf life of the shrimp by about 1 d. Therefore, the double-layer film demonstrated potential as a smart packaging material for real-time monitoring of meat product freshness.

Red cabbage extract immobilized in bacterial cellulose film as an eco-friendly sensor to monitor microbial contamination and gamma irradiation of stored cucumbers

The aim of the present study is to develop a pH-sensing biopolymer film based on the immobilization of red cabbage extract (RCE) within bacterial cellulose (BC) to detect contamination and gamma radiation exposure in cucumbers. The results obtained show a sensitivity to pH changes for RCE in its aqueous form and that incorporated within BC films (RCE-BC), both showed color change correlated to bacterial growth (R2 = 0.91), this was supported with increase in pH values from 2 to 12 (R2 = 0.98). RCE and RCE-BC exposure to gamma radiation (0, 2.5, 5, 10, 15, 20, 25 kGy) resulted in gradual decrease in color that was more evident in RCE aqueous samples. To sense bacterial contamination of cucumbers, the total count was followed at 0, 5, 10 and 15 days in cold storage conditions and was found to reach 9.13 and 5.47 log cfu/mL for non-irradiated and 2 kGy irradiated samples, respectively. The main isolates detected throughout this storage period were identified as Pseudomonas fluorescens, Erwinia sp. Pantoea agglomerans using matrix assisted laser desorption ionization-time of flight-ms (MALDI-TOF-MS). Bacterial growth in stored irradiated cucumbers was detected by color change within 5 and 10 days of storage, after which there was no evident change. This is very useful since contamination within the early days of storage cannot be sensed with the naked eye. This study is the first to highlight utilizing RCE and RCE-BC as eco-friendly pH-sensing indicator films for intelligent food packaging to detect both food contamination and gamma preservation for refrigerator stored cucumbers.

Food applications of bioactive biomaterials based on gelatin and chitosan

Food packaging must guarantee the products' quality during the different operations including packing and maintenance throughout transportation and storage until to consumption. Thus, it should satisfy, both, food freshness and quality preservation and consumers health safety. Natural bio-sourced polymers have been explored as safe edible materials for several packaging applications, being interestingly carrier of bioactive substances, once added to improve films' properties. Gelatin and chitosan are among the most studied biomaterials for the preparation of edible packaging films due to their excellent characteristics including biodegradability, compatibility and film-forming property. These polymers could be used alone or in combination with other polymers to produce composite films with the desired physicochemical and mechanical properties. When incorporated with bioactive substances (natural extracts, polyphenolic compounds, essential oils), chitosan/gelatin-based films acquired various biological properties, including antioxidant and antimicrobial activities. The emerging bioactive composite films with excellent physical attributes represent excellent packaging alternative to preserve different types of foodstuffs (fruits, meat, fish, dairy products, …) and have shown great achievements. This chapter provides the main techniques used to prepare gelatin- and chitosan- based films, showing some examples of bioactive compounds incorporated into the films' matrix. Also, it illustrates the outstanding advantages given by these biomaterials for food preservation, when used as coating and wrapping agents.

Integration of lanthanide MOFs/methylcellulose-based fluorescent sensor arrays and deep learning for fish freshness monitoring

Preserving fish meat poses a significant challenge due to its high protein and low fat content. This study introduces a novel approach that utilizes a common type of lanthanide metal-organic frameworks (Ln-MOFs), EuMOFs, in combination with 5-fluorescein isothiocyanate (FITC) and methylcellulose (MC) to develop fluorescent sensor arrays for real-time monitoring the freshness of fish meat. The EuMOF-FITC/MC fluorescence films were characterized with excellent fluorescence response, ideal morphology, good mechanical properties, and improved hydrophobicity. The efficacy of the fluorescence sensor array was evaluated by testing various concentrations of spoilage gases (such as ammonia, dimethylamine, and trimethylamine) within a 20-min timeframe using a smartphone-based camera obscura device. This sensor array enables the real-time monitoring of fish freshness, with the ability to preliminarily identify the freshness status of mackerel meat with the naked eye. Furthermore, the study employed four convolutional neural network (CNN) models to enhance the performance of freshness assessment, all of which achieved accuracy levels exceeding 93 %. Notably, the ResNext-101 model demonstrated a particularly high accuracy of 98.97 %. These results highlight the potential of the EuMOF-based fluorescence sensor array, in conjunction with the CNN model, as a reliable and accurate method for real-time monitoring the freshness of fish meat.

Sustainable food packaging: Harnessing biowaste of Terminalia catappa L. for chitosan-based biodegradable active films for shrimp storage

Shrimp, a globally consumed perishable food, faces rapid deterioration during storage and marketing, causing nutritional and economic losses. With a rising environmental consciousness regarding conventional plastic packaging, consumers seek sustainable options. Utilizing natural waste resources for packaging films strengthens the food industry. In this context, we aim to create chitosan-based active films by incorporating Terminalia catappa L. leaves extract (TCE) to enhance barrier properties and extend shrimp shelf life under refrigeration. Incorporation of TCE improves mechanical, microstructural, UV, and moisture barrier properties of the chitosan film due to cross-linking interactions, resulting in robust, foldable packaging film. Active TCE film exhibits high antioxidant property due to polyphenols. These films also exhibited low wettability and showed hydrophobicity than neat CH films which is essential for meat packaging. These biodegradable films offer an eco-friendly end-of-life option when buried in soil. TCE-loaded films effectively control spoilage organisms, prevent biochemical spoilage, and maintain shrimp freshness compared to neat CH films during refrigerated condition. The active TCE film retains sensory attributes better than neat chitosan, aligning with consumer preference. The developed edible and active film from waste sources might offer sustainable, alternative packaging material with a lower carbon footprint than petroleum-based sources.

Alizarin-embedded γ-cyclodextrin-based metal-organic framework in a methylcellulose/polyvinyl alcohol film for maintaining and monitoring grass carp freshness

Multifunctional packaging films that monitor and maintain fish freshness hold significant potential for use in the food industry. This study introduces a multifunctional intelligent packaging film comprising alizarin (ALI)-embedded cubic γ-cyclodextrin metal-organic frameworks (γ-CD-MOFs) (denoted as γ-CD-MOFs@ALI) in a methylcellulose/polyvinyl alcohol (MP)-based matrix to achieve colorimetric monitoring and enhanced preservation of fish freshness. The MP/γ-CD-MOFs@ALI reveals a rapid color transition in 3 min from yellow color progressively darkens to purple as the pH increases from 2.0 to 10.0. And it is proved that the as-prepared film owns high antibacterial activity against Gram-positive bacteria (S. aureus), impressive ABTS+ radical scavenging rates of 85.54 ± 1.25 %, and effective ALI sustained-release properties. The intelligent packaging film exhibits an excellent colorimetric response to total volatile basic nitrogen and provides exceptional freshness preservation performance, effectively prolonging the shelf life of Ctenopharyngodon idella (grass carp) under 25 °C to 42 h.

Advanced technologies in biodegradable packaging using intelligent sensing to fight food waste

The limitation of conventional packaging in demonstrating accurate and real-time food expiration dates leads to food waste and foodborne diseases. Real-time food quality monitoring via intelligent packaging could be an effective solution to reduce food waste and foodborne illnesses. This review focuses on recent technological advances incorporated into food packaging for monitoring food spoilage, with a major focus on paper-based sensors and their combination with smartphone. This review paper offers a comprehensive exploration of advanced macromolecular technologies in biodegradable packaging, a general overview of paper-based probes and their incorporation into food packaging coupled with intelligent sensing mechanisms for monitoring food freshness. Given the escalating global concerns surrounding food waste, our manuscript serves as a pivotal resource, consolidating current research findings and highlighting the transformative potential of these innovative packaging solutions. We also highlight the current intelligent paper-based food freshness sensors and their various advantages and limitations. Examples of implementation of paper-based sensors/probes for food storage and their accuracy are presented. Finally, we examined how intelligent packaging can be an alternative to reduce food waste. Several technologies discussed here have good potential to be used in food packaging for real-time food monitoring, especially when combined with smartphone diagnosis.

Intelligent active films of sodium alginate and konjac glucomannan mixed by Lycium ruthenicum anthocyanins and tea polyphenols for milk preservation and freshness monitoring

To achieve real-time monitoring of food freshness, a pH-responsive film based on sodium alginate-konjac glucomannan loaded with Lycium ruthenicum anthocyanins (LRA) was prepared, with the addition of tea polyphenols (TP) to enhance the stability of LRA. The surface structure of the films was observed by AFM. The results of FTIR and molecular docking simulation showed that LRA and TP were bound to polysaccharide by hydrogen bonds. The mechanical properties, barrier properties, and antioxidant/antibacterial properties of the films were significantly improved and the films showed obvious color response to pH. Notably, the AFM images showed TP and LRA could lead to more severe damage to the bacterial structure. The results of molecular docking simulation suggested that TP and LRA could act on different components of the bacterial cell wall, indicating their synergistic mechanism in antimicrobial activity. Moreover, the stability of LRA was improved due to the interactions of TP and polysaccharides with LRA. The aggregates formed by TP and LRA were clearly observed by AFM. Finally, the film showed excellent preservation and freshness monitoring effect in milk. In conclusion, TP-LRA-SA-KGM intelligent film exhibited excellent performance and represented a promising novel food packaging material with potential applications.

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

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

Development of Smart Films of a Chitosan Base and Robusta Coffee Peel Extract for Monitoring the Fermentation Process of Pickles

Smart film is widely used in the field of food packaging. The smart film was prepared by adding anthocyanin-rich Robusta coffee peel (RCP) extract into a chitosan (CS)-glycerol (GL) matrix by a solution-casting method. By changing the content of RCP (0, 10%, 15% and 20%) in the CS-GL film, the related performance indicators of CS-GL-RCP films were studied. The results showed that the CS-GL-RCP films had excellent mechanical properties, and CS-GL-RCP15 film maintained the tensile strength (TS) of 16.69 MPa and an elongation-at-break (EAB) of 18.68% with RCP extract. CS-GL-RCP films had the best UV-vis light barrier property at 200-350 nm and the UV transmittance was close to 0. The microstructure observation results showed that CS-GL-RCP films had a dense and uniform cross section, which proved that the RCP extract had good compatibility with the polymer. In addition, the CS-GL-RCP15 film was pH-sensitive and could exhibit different color changes with different pH solutions. So, the CS-GL-RCP15 film was used to detect the fermentation process of pickles at 20 ± 1 °C for 15 days. The pickles were stored in a round pickle container after the boiling water had cooled. The color of the CS-GL-RCP15 film changed significantly, which was consistent with the change of pickles from fresh to mature. The color of the smart film changed significantly with the maturity of pickles, and the difference of ΔE of film increased to 8.89 (15 Days), which can be seen by the naked eye. Therefore, CS-GL-RCP films prepared in this study provided a new strategy for the development of smart packaging materials.

Preparation and characterization of ultrasound-assisted essential oil-loaded nanoemulsions stimulated pullulan-based bioactive film for strawberry fruit preservation

Ultrasound is a high-energy approach that can help with homogenization and dispersion in cavitation. In this study, nanoemulsions of curcumin and orange essential oil were prepared with ultrasound treatment at different times. The ultrasound-treated nanoemulsions for 10 min exhibited the smallest droplet size, the best storage, and higher thermal stability. The pullulan-based film with ultrasound-assisted nanoemulsions exhibited improved water vapor permeability and moisture content and the highest tensile strength and elongation at break. The structural analysis showed that ultrasonic treatment enhanced the H-bond, resulting in a more orderly molecular arrangement and intermolecular compatibility. Furthermore, the bioactive film had the maximum oil retention time. It possessed excellent bacteriostatic properties against Escherichia coli and Staphylococcus aureus due to the smallest oil droplets and uniform distribution in the film matrix. Besides, the weight loss and deterioration of the strawberry fruit were effectively reduced, thus prolonging the shelf life.

Robust microfluidic construction of polyvinyl pyrrolidone microfibers incorporated with W/O emulsions stabilized by amphiphilic konjac glucomannan

In this work, we prepared polyvinyl pyrrolidone (PVP) microfibers incorporated water-in-oil (W/O) emulsions. The W/O emulsions were fabricated by hexadecyl konjac glucomannan (HKGM, emulsifier), corn oil (oil phase) and purple corn anthocyanins (PCAs, water phase). The structures and functions of emulsions and microfibers were characterized by confocal laser scanning (CLSM) and scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Raman and nuclear magnetic resonance (NMR) spectroscopy. The results showed that W/O emulsions exhibited good storage stability for 30 d. Microfibers presented ordered and uniform arrays. Compared with pure PVP microfiber films, the addition of W/O emulsions with PCAs improved the water resistance (WVP from 1.28 to 0.76 g mm/m² day kPa), mechanical strength (Elongation at break from 18.35 % to 49.83 %), antioxidation (free radical scavenging rate from 2.58 % to 16.37 %), and antibacterial activity (inhibition zone against E. coli: 27.33 mm and inhibition zone against S. aureus: 28.33 mm) of microfiber films. Results showed that microfiber film exhibited controlled release of PCAs in W/O emulsions, and about 32 % of the PCAs were released from the microfiber film after 340 min. The as-prepared microfiber films exhibited potential applications for food packaging.

Highly biologically active and pH-sensitive collagen hydrolysate-chitosan film loaded with red cabbage extracts realizing dynamic visualization and preservation of shrimp freshness

Accurate and efficient detection of food freshness is of great significance to guarantee food safety. Herein, pH sensitive colorimetric films with considerable biological activities have been prepared by combining red cabbage anthocyanin extracts (RCE) with collagen hydrolysate-chitosan (CH-CS) matrix film. The formation mechanism of CH-CS-RCE films was discussed by SEM, FT-IR and XRD, which showed that RCE was successfully fixed in CH-CS film through hydrogen bonding and electrostatic interaction. The CH-CS-RCE films exhibited good mechanical properties, high barrier ability, excellent thermal stability, significant antioxidant and antimicrobial activity, and especially sensitive response to pH and ammonia. Fickian diffusion was the main mechanism for the release of RCE from CH-CS-RCE films and such release mechanism facilitated the maintenance of functional features of films. During the storage of shrimps at 4 °C, CH-CS-RCE2% showed a remarkable preservation effect on shrimps, and their shelf life was prolonged from 2 d to 5 d. Furthermore, CH-CS-RCE2% provided a dynamic visual color switching to detect the freshness of shrimp, realizing real-time monitoring of freshness. Color information (RGB) extracted via smartphone APP was used to enhance the accuracy and universality of freshness indication. Thus, this multifunctional film has great potential in food preservation and freshness monitoring.

A double-layer smart film based on gellan gum/modified anthocyanin and sodium carboxymethyl cellulose/starch/Nisin for application in chicken breast

In order to overcome this challenge of poor stability of natural anthocyanins in intelligent packaging materials, roselle anthocyanin (RA) was first modified by acetic acid, and then a double-layer smart indication antimicrobial film was developed using modified roselle anthocyanin (MRA)-gellan gum (GG) as the inner layer and sodium carboxymethyl cellulose (CMC)-starch (ST)-Nisin as the outer layer. UV spectra revealed that acetic acid was successfully grafted onto RA, which dramatically improved their thermal stability, antioxidant capabilities, photostability, and pH stability. The bilayer films were successfully prepared, as revealed by scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction measurements. In comparison to GG-MRA and CMC-ST-Nisin films, the water content, water solubility, mechanical characteristics, water vapor barrier, oxygen barrier, and hydrophobicity of GG-MRA@CMC-ST-Nisin films were significantly enhanced. The presence of the outer layer films significantly enhanced the UV-vis light barrier, opacity, antioxidant and antibacterial properties of the inner layer films. When the films were applied to chicken breast, it was found that the indicator films not only monitored the freshness of the chicken in real-time but also that the GG-MRA film and the double-layer film were effective in extending the shelf life of the chicken by 1 and 2 days, respectively, compared to the control group.

Recent advancements in natural colorants and their application as coloring in food and in intelligent food packaging

Colorants are widely employed in the food industry as an essential ingredient in many products since color is one of the most valued attributes by consumers. Furthermore, the utilization of colorants is currently being extended to the food packaging technologies. The objective of this review was to compile recent information about the main families of natural coloring compounds, and to describe their real implications in food coloring. In addition, their technological use in different food systems (namely, bakery products, beverages, meat and meat products, and dairy products) and their utilization in intelligent packaging to monitor the freshness of foodstuffs with the aim of extending food shelf life and improving food properties was discussed. The potential of using natural colorant in different food to improve their color has been demonstrated, although color stability is still a challenging task. More interestingly, the application of intelligent colorimetric indicators to exhibit color changes with variations in pH can enable real-time monitoring of food quality.

Reflections on food security and smart packaging

Estimating the number of COVID-19 cases in 2020 exacerbated the food contamination and food supply issues. These problems make consumers more concerned about food and the need to access accurate information on food quality. One of the main methods for preserving the quality of food commodities for export, storage, and finished products is food packaging itself. In the food industry, food packaging has a significant role in the food supply which acts as a barrier against unwanted substances and preserves the quality of the food. Meanwhile, packaging waste can also harm the environment; namely, it can become waste in waterways or become garbage that accumulates because it is nonrenewable and nonbiodegradable. The problem of contaminated food caused by product packaging is also severe. Therefore, to overcome these challenges of safety, environmental impact, and sustainability, the role of food packaging becomes very important and urgent. In this review, the authors will discuss in more detail about new technologies applied in the food industry related to packaging issues to advance the utilization of Smart Packaging and Active Packaging.

Introduction of Curdlan Optimizes the Comprehensive Properties of Methyl Cellulose Films

The good oxygen barrier and hydrophobic properties of curdlan (CL) film might be suitable complements for MC film, and its similar glucose unit and thermal-gel character might endow the methyl cellulose (MC)/CL blended system with compatibility and good comprehensive properties. Thus, MC/CL blended films were developed. The effects of MC/CL blend ratios on the microstructures and physical properties of the blends were characterized by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), oxygen and water vapor permeability testing, dynamic mechanical analysis (DMA), light transmittance testing, tensile testing, hydrophilic property testing, and water solubility testing. The introduction of CL affected the molecular aggregation and crystallization of the MC molecules, suggesting MC-CL molecular interactions. The cross-sectional roughness of the MC/CL film increased with an increase in CL content, while the surface of the MC/CL 5:5 film was smoother than those of the MC/CL 7:3 and 3:7 films. Only one glass transition temperature, which was between that of the MC and CL films, was observed for the MC/CL 7:3 and MC/CL 5:5 films, indicating the good compatibility of the MC and CL molecules at these two blend ratios. The hydrophobicity and water insolubility increased with the CL content, which was due to the combined effects of more hydrophobic cavities in the CL triple-helix and increased surface roughness. Increased oxygen barrier properties with increasing CL content might be a combined effect of the increased hydrogen bonds and hydrophilic ektexines of the CL triple-helix. The elongations of the blended films were higher than those of the MC film, which might be related to its increased water content. The MC/CL 7:3 and MC/CL 5:5 films retained the good light transmittance and tensile strength of the MC film, which corresponded well to their good compatibility and might be due to the effects of the MC-CL molecular interactions and the relative smooth morphologies. MC/CL 5:5 showed improved water vapor barrier properties, which might be due to its smooth surface morphologies. This research offers new MC based films with improved properties and good compatibility, providing great potential for use as edible coatings, capsules, and packaging materials.

Basella alba stem extract integrated poly (vinyl alcohol)/chitosan composite films: A promising bio-material for wound healing

Natural extract-based bio-composite material for wound healing is gaining much attention due to risk of infection and high cost of commercial wound dressing film causes serious problem on the human well-being. Herein, the study outlines the preparation of Poly (vinyl alcohol)/Chitosan/Basella alba stem extract (BAE) based bio-composite film through solvent casting technique and well characterized for wound healing application. Incorporation of BAE into Poly (vinyl alcohol)/Chitosan matrix has shown existence of secondary interactions confirmed by FT-IR analysis. Good morphology, thermal stability and significant improvement in flexibility (∼63.38 %) of the films were confirmed by SEM, TGA and Mechanical test results, respectively. Hydrophilic property (∼9.04 %), water vapor transmission rate (∼70.07 %), swelling ability (∼14.7 %) and degradation rate (∼14.04 %) were enhanced with increase in BAE content. In-vitro studies have shown good antibacterial activity against foremost infectious bacterial strains S. aureus and E. coli. Additionally, BAE integrated Poly (vinyl alcohol)/Chitosan film has amplified anti-inflammatory (∼79.38 %) property, hemocompatibility and excellent biocompatibility (94.9 %) was displayed by cytotoxicity results. Moreover, in-vitro scratch assay and cell adhesion test results illustrated prominent wound healing (96.5 %) and adhesion. Overall results of the present work proclaim that developed bio-composite film could be utilized as a biomaterial in wound care applications.

Chitosan Edible Films and Coatings with Added Bioactive Compounds: Antibacterial and Antioxidant Properties and Their Application to Food Products: A Review

Chitosan is the deacetylated form of chitin regarded as one of the most abundant polymers and due to its properties, both chitosan alone or in combination with bioactive substances for the production of biodegradable films and coatings is gaining attention in terms of applications in the food industry. To enhance the antimicrobial and antioxidant properties of chitosan, a vast variety of plant extracts have been incorporated to meet consumer demands for more environmentally friendly and synthetic preservative-free foods. This review provides knowledge about the antioxidant and antibacterial properties of chitosan films and coatings enriched with natural extracts as well as their applications in various food products and the effects they had on them. In a nutshell, it has been demonstrated that chitosan can act as a coating or packaging material with excellent antimicrobial and antioxidant properties in addition to its biodegradability, biocompatibility, and non-toxicity. However, further research should be carried out to widen the applications of bioactive chitosan coatings to more foods and industries as well was their industrial scale-up, thus helping to minimize the use of plastic materials.

Preparation and characterization of an intelligent film based on fish gelatin and Coleus scutellarioides anthocyanin to monitor the freshness of rainbow trout fish fillet

In this study, a pH-sensitive indicator based on fish gelatin and Coleus scutellarioides anthocyanin extract (CSAE) was prepared and characterized. Films were prepared using the solvent casting method and different levels of CSAE, including 10 ml (CSG1), 20 ml (CSG2), and 30 ml (CSG3), and 0 ml (CSG0) as a control sample. The mechanical, optical, and pH sensing of active films and the release of anthocyanins from the films were investigated. The relationship between the total volatile basic nitrogen (TVB-N) of fish fillets and a* color index of films was studied. By incorporation of CSAE, the flexibility of films increased, while the tensile strength and UV-Vis light transmittance through the films decreased (p < .05). The films containing the CSAE had a darker, yellowish, and reddish color than the control film. There was a significant relationship between the pH variation and the film color. The films had a purple color at acidic pH, and their color changed to green at an alkaline pH, indicating the sensitivity of the produced films to pH changes. There was a significant relationship between the TVB-N value of fish fillets and the a* index of the film during the 16 h storage time. The results showed that by increasing TVB-N values of the fillets, the a* color index decreased, and the films' color changed from purple to colorless. In summary, the active films prepared with fish gelatin and CSAE could be used as pH-sensitive intelligent packaging to display the freshness of fishery products.

Bilayer pH-sensitive colorimetric indicator films based on zein/gellan gum containing black rice (Oryza sativa L.) extracts for monitoring of largemouth bass (Micropterus salmoides) fillets freshness

Anthocyanins as natural pH-sensitive material can be used to determine the freshness of largemouth bass (Micropterus salmoides) fillets. However, it is easily degraded. Using zein as the protective layer to improve the light blocking ability of the film, gellan gum (GG) and black rice extracts (BRE) as the sensing layer, a bilayer colorimetric indicator film for monitoring fish spoilage was developed. The functionality and stability of bilayer film and GG single film were compared. As compared to GG single film, Zein/GG bilayer film had stronger intermolecular interactions, higher mechanical properties, and higher optical barrier properties. Notably, Zein/GG-8 % BRE bilayer film exhibited higher stability than GG-8 % BRE film when the films were exposed to room temperature for 30 days. Zein/GG-8 % BRE bilayer film were further used to monitor freshness of largemouth bass fillets during storage. Zein/GG-8 % BRE bilayer film demonstrated a noticeable color change from red to brown when largemouth bass fillets spoiled. Moreover, the ∆E of films showed a good correlation with TVB-N of largemouth bass fillets (R² = 0.985). Our research results show that the Zein/GG-BRE bilayer indicator film has great potential application prospects in monitoring fish freshness.

A smart film incorporating anthocyanins and tea polyphenols into sodium carboxymethyl cellulose/polyvinyl alcohol for application in mirror carp

Multifunctional food packaging films were developed based on polyvinyl alcohol (PVA), sodium carboxymethyl cellulose (CMC), tea polyphenol (TP) and black carrot anthocyanin (CA). Results of Zeta potential, scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction showed that CA enhanced the stability of the particle dispersion system through hydrogen bonding and electrostatic interactions, promoted the compatibility between TP and PVA-CMC (PC) substrates, and enhanced the binding between the components of the films. Because of the interaction of TP and CA, PC-TP-CA films had better water resistance and water vapor barrier properties, thermal stability, antioxidant and antimicrobial properties. PC-CA and PC-TP-CA films exhibited excellent UV-blocking properties. They also showed distinct color responsiveness in the pH range of 2-13, significant sensitivity to ammonia vapor in a short period of time and excellent color stability over 20 days of storage under different conditions. When the film was applied to fish, it was found that PC-TP-CA film could extend the shelf life of fish by 1-2 days and successfully monitor the freshness of the fish in real-time. Considering all the physical and functional properties, the non-toxic and biodegradable PC-TP-CA film has excellent potential as a new multifunctional food packaging material in the future.

Development of Shrimp Freshness Indicating Films by Embedding Anthocyanins-Rich Rhododendron simsii Flower Extract in Locust Bean Gum/Polyvinyl Alcohol Matrix

Freshness indicating films containing anthocyanins are one type of smart packaging technology. Anthocyanins in the films can show visual color changes when food spoilage occurs, thereby indicating the freshness degree of food in real-time. Rhododendron simsii is a landscape plant with attractive flowers that are abundant in anthocyanins. In this study, smart packaging films were prepared by embedding 2% and 4% R. simsii flower anthocyanins (RA) in locust bean gum- (LBG) and polyvinyl alcohol- (PVA) based matrices. The micro-structure, barrier, mechanical, thermal, antioxidant, and color-changeable properties of the films were determined. The potential application of the films in indicating the freshness of shrimp at 4 °C was also investigated. Results showed that the RA interacted with the LBG/PVA matrices through hydrogen bonds, which significantly improved the barrier, mechanical, thermal, antioxidant, pH-sensitive, and ammonia-sensitive properties of the films. Meanwhile, the performance of the films was remarkably influenced by the content of the RA. The film containing 4% RA had the highest light blocking ability, tensile strength (38.32 MPa), elongation at break (58.18%), and antioxidant activity, and also showed the lowest water vapor permeability (22.10 × 10^-11 g m^-1 s^-1 Pa^-1) and oxygen permeability (0.36 cm³ mm m^-2 day^-1 atm^-1). The films containing 2% and 4% RA could effectively change their colors when the level of total volatile basic nitrogen in the shrimp exceeded the safe value, which demonstrated the suitability of the films for indicating the freshness degree of shrimp.

pH-Responsive Color Indicator of Saffron (Crocus sativus L.) Anthocyanin-Activated Salep Mucilage Edible Film for Real-Time Monitoring of Fish Fillet Freshness

Researchers have been focusing increasingly on preparing innovative packaging films made from renewable and biodegradable materials in recent years. This research set out to fabricate and analyze pH-sensitive edible films based on salep mucilage combined with anthocyanin from saffron (Crocus sativus L.) (SAAs). A casting technique was developed with varying concentrations of SAAs (0, 2.5, 5, 7.5, and 10%v/v) pH-sensitive edible films. The surface morphology, physicochemical, barrier, and mechanical properties, as well as the pH sensitivity of films, were investigated. The results showed SAAs increased thickness, water solubility, moisture content, and oxygen permeability (O2P) up to 199.03 µm, 63.71%, 14.13%, and 47.73 (cm3 µm m−2 day−1 kPa−1), respectively, of the pH-sensitive salep mucilage edible indicator films. As expected, the SAAs concentration from 0% to 10%v/v decreased tensile strength, transparency, and contact angle to 11.94 MPa, 14.27%, and 54.02°, respectively. Although achieving the highest elongation at the break (108%) and the lowest water vapor permeability (WVP) (1.39 g s−1 m−1 Pa−1 × 10−11), the pH-sensitive edible indicator film containing 5 %v/v of SAAs showed the best results. An investigation of pH sensitivity revealed that the solution’s pH variation altered the SAAs color. When the pH was raised from 3 to 11, the SAAs’ color shifted from pink to brown. The SAAs-halochromic salep mucilage edible indicator film was employed as a label in an experiment to track the degradation of fish fillets stored at 4 °C, revealing that the halochromic indicator changed color from yellow to brown as the fish was stored. Our findings show that SAAs-loaded salep mucilage indicator films help monitor real-time food deterioration.

Colorimetric Indicators Based on Anthocyanin Polymer Composites: A Review

This review explores the colorimetric indicators based on anthocyanin polymer composites fabricated in the last decade, in order to provide a comprehensive overview of their morphological and compositional characteristics and their efficacy in their various application fields. Notably, the structural properties of the developed materials and the effect on their performance will be thoroughly and critically discussed in order to highlight their important role. Finally, yet importantly, the current challenges and the future perspectives of the use of anthocyanins as components of colorimetric indicator platforms will be highlighted, in order to stimulate the exploration of new anthocyanin sources and the in-depth investigation of all the possibilities that they can offer. This can pave the way for the development of high-end materials and the expansion of their use to new application fields.

A sub-freshness monitoring chitosan/starch-based colorimetric film for improving color recognition accuracy via controlling the pH value of the film-forming solution

The demand for intelligent packaging in food sub-freshness monitoring is increasing. Herein, a pH and NH3 responsing colorimetric film (PS-CH-LCA) was fabricated based on potato starch (PS), chitosan (CH) and Lonicera caerulea L. anthocyanins (LCA) via controlling the pH value of the film-forming solution, and was applied to the real-time monitoring of shrimp freshness. The PS-CH-LCA pH 2.5 film exhibited the highest tensile strength (6.43 MPa), the lowest water solubility (33.11%) and the most sensitive color responsiveness. Morphological and structural results revealed that CH was attached to the surface of PS via hydrogen bond, and anthocyanins were well immobilized in the film-forming matrix. The sensitive color change and its high correlation with spoilage indices demonstrated the PS-CH-LCA pH 2.5 film well indicated fresh, sub-fresh, spoiled level of shrimp. The results solved the limitation of chitosan-based packaging films in undistinguishable colorimetric endpoints, providing a new strategy for indicating the sub-freshness of food packaging.

Development of pH-responsive konjac glucomannan/pullulan films incorporated with acai berry extract to monitor fish freshness

In this work, konjac glucomannan (KGM)-based film reinforced with pullulan (PL) and acai berry extract (ABE) was developed by solvent casting method. The as-prepared films performed pH-sensitive properties, which can be potentially applied for fish freshness detection. Rheology, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) were used to characterize chemical structure and morphology of ABE-loaded KGM/PL (KP) films (KP-ABE). FT-IR spectrum indicated that hydrogen bond dominated the formation of KP-ABE films. Adding PL contributed to enhanced mechanical properties of KGM film with increased tensile strength (TS) from 21.25 to 50.27 MPa and elongation at break (EAB) from 10.64 to 19.19 %. Incorporating ABE upgraded flexibility, UV-shielding, thermostability, water barrier (decreased Water vapor permeability (WVP) from 2.07 to 1.67 g·mm/m²·day kPa), antioxidant, and antibacterial ability of KP films, but weakened TS. In addition, KP-ABE films can reflect fish freshness in real time through color variability. Therefore, KP-ABE films exhibited potential applications in intelligent food packaging materials.

Fabrication of intelligent/active films based on chitosan/polyvinyl alcohol matrices containing Jacaranda cuspidifolia anthocyanin for real-time monitoring of fish freshness

The present work describes the natural anthocyanin from Jacaranda cuspidifolia (JC) flower immobilized within a biopolymer matrix composed of chitosan (CS) and polyvinyl alcohol (PVA) gave novel intelligent/active packaging films (CPC). We introduced microwave irradiation to prepare polymeric composite films noticed faster mixing of the polymers and extract take place than the conventional method. The prepared composite films are characterized by various analytical and spectroscopic techniques. The smooth SEM images demonstrated CS/PVA matrix miscibility and compatibility with anthocyanin for the film formation. The addition of anthocyanin to the CS/PVA films significantly reduced UV-Vis light transmission, while causing a slight decrease in the films transparency. An increased anthocyanin concentration on polymer films showed improved oxygen permeability (77.09 %), moisture retention capacity (11.64 %), and water vapor transmission rate (43.10 %) substantially. Additionally, the prepared CPC smart films exhibited strong antioxidant (97.92 %) as well as antibacterial activities against common foodborne pathogens such as S. aureus, and E. coli. Furthermore, the prepared smart films demonstrated pink color in acidic, while grey to yellowish in basic solvent. Further, the color response of the freshness label was consistent with the spoilage Total Volatile Basic-Nitrogen (TVB-N) content determined in the fish samples with varied time period. The CPC smart films also showed promising application in terms of monitoring freshness of the fish fillets at room temperature. The obtained results suggested that, the prepared CPC smart films have potential to be used as quality indicator in the marine food packaging system.