Novel ammonia-responsive carboxymethyl cellulose/Co-MOF multifunctional films for real-time visual monitoring of seafood freshness

High-performance carboxymethyl starch/PVA based intelligent packaging films engineered with Cu-Trp nanocrystal as functional compatibilizer

A spindle-like Cu-based framework (Cu-Trp, Trp = L-Tryptophan) nanocrystal with ammonia-responsiveness was fabricated via simple aqueous solution approach, and it was subsequently explored as a functional compatibilizer of carboxymethyl starch/polyvinyl alcohol (CMS/PVA) blend toward constructing high-performance intelligent packaging films. The results showed that incorporation of Cu-Trp nanocrystal into CMS/PVA blend resulted in significant promotions regarding to the compatibility, mechanical strength (42.92 MPa), UV-blocking (with UV transmittance of only 2.4%), and water vapor barrier effectiveness of the blend film. Besides, the constructed CMS/PVA/Cu-Trp nanocomposite film exhibited superb long-term color stability, favorable antibacterial capacity (over 98.0%) toward both E. coli and S. aureus bacteria, as well as color change ability under ammonia environment. Importantly, the application trial confirmed that the CMS/PVA/Cu-Trp nanocomposite film is capable of visually monitoring shrimp spoilage during storage. These results implied that the CMS/PVA/Cu-Trp nanocomposite film holds tremendous potential as an intelligent active packaging material.

Developing colorimetric ammonia-sensing nanocomposite films based on potato starch/PVA and ZnCu-BTC nanorods for real-time monitoring food freshness

Smart packaging material capable of real-time monitoring of food freshness is essential for ensuring food safe. At present, colorimetric ammonia-sensing smart film often possesses issues with complicated production, high cost, and inferior long-term colour stability. Herein, Zinc‑copper bimetallic organic framework (ZnCu-BTC, BTC = 1,3,5-benzenetricarboxylate acid) nanorods with colorimetric ammonia-responsiveness were synthesized by adopting facile aqueous solution method, which were then explored as nano inclusions in potato starch/polyvinyl alcohol (PS/PVA) composite film towards developing high-performance smart packaging material. The results demonstrated that the introduction of ZnCu-BTC nanorods within PS/PVA brought about remarkable improvement in blend compatibility, accompanied by a boost in tensile strength to 47.2 MPa, as well as enhanced ultraviolet (UV) blocking efficacy (over 95.0 %). Additionally, the barrier properties of PS/PVA film against water vapor and oxygen were fortified due to the addition of ZnCu-BTC. More importantly, the developed PS/PVA/ZnCu-BTC nanocomposite film displayed satisfactory antibacterial activity (over 99 %) against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), favorable colorimetric ammonia-sensing ability, and long-term colour stability. The ZnCu-BTC incorporated PS/PVA nanocomposite film could grant real-time detection of prawn freshness decline via remarkable colour change, indicating vast promise for smart food packaging applications.

Carboxymethyl cellulose-based photothermal film: A sustainable packaging with high barrier and tensile strength for food long-term antibacterial protection

Traditional packaging materials feed the growing global food protection. However, these packaging materials are not conducive to environment and have not the ability to kill bacteria. Herein, a green and simple strategy is reported for food packaging protection and long-term antibacterial using carboxymethylcellulose-based photothermal film (CMC@CuS NPs/PVA) that consists of carboxymethyl cellulose (CMC) immobilized copper sulfide nanoparticles (CuS NPs) and polyvinyl alcohol (PVA). With satisfied oxygen transmittance (0.03 cc/m2/day) and water vapor transmittance (163.3 g/m2/day), the tensile strength, tear strength and burst strength reached to 3401.2 N/m, 845.7 mN and 363.6 kPa, respectively, which could lift 4.5 L of water. The composite film had excellent photothermal conversion efficiency and photothermal stability. Under the irradiation of near infrared (NIR), it can rapidly heated up to 197 °C within 25 s. The antibacterial analysis showed that the inhibition rate of composite film against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) could all reach >99 %. Furthermore, the synthesized CuS NPs was well immobilized and the residual rate of copper kept 98.7 % after 10 days. Noticeably, the composite film can preserve freshness of strawberries for up to 6 days. Therefore, the composite film has potential application for food antibacterial protection.

Preparation of curcumin-loaded chitosan/polyvinyl alcohol intelligent active films for food packaging and freshness monitoring

To fulfill the current need for intelligent active food packaging. This study incorporated the curcumin inclusion complexes (CUR-CD) into chitosan/polyvinyl alcohol polymer to develop a new intelligent active film. The structures of films were analyzed by Fourier-transform infrared (FT-IR), scanning electron microscope (SEM), and so on. The CP-Cur150 film displays exceptional mechanical properties, water vapor barrier, and UV blocking capabilities as demonstrated by physical analysis. The CP-Cur150 film exhibited free radical scavenging rates on 2,2-diazo-di-3-ethylbenzothiazolin-6-sulfonic (ABTS) (98 %) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (87 %). Additionally, it showed inhibitory effects on Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli), reducing live colony counts by approximately 2.7 and 1.3 Log10 CFU/mL, respectively. The films were used to monitor the shrimp's freshness in real time. With the spoilage of shrimp, the film exhibited clear color fluctuations, from light yellow to red. In addition, the evaluation of the impact of films on pork pH, total volatile basic nitrogen, and total bacterial counts demonstrated that the CP-Cur150 film displayed the most significant effectiveness in preserving freshness, thereby extending the shelf life of pork.

Small particles, big effects: How nanoparticles can enhance plant growth in favorable and harsh conditions

By 2050, the global population is projected to reach 9 billion, underscoring the imperative for innovative solutions to increase grain yield and enhance food security. Nanotechnology has emerged as a powerful tool, providing unique solutions to this challenge. Nanoparticles (NPs) can improve plant growth and nutrition under normal conditions through their high surface-to-volume ratio and unique physical and chemical properties. Moreover, they can be used to monitor crop health status and augment plant resilience against abiotic stresses (such as salinity, drought, heavy metals, and extreme temperatures) that endanger global agriculture. Application of NPs can enhance stress tolerance mechanisms in plants, minimizing potential yield losses and underscoring the potential of NPs to raise crop yield and quality. This review highlights the need for a comprehensive exploration of the environmental implications and safety of nanomaterials and provides valuable guidelines for researchers, policymakers, and agricultural practitioners. With thoughtful stewardship, nanotechnology holds immense promise in shaping environmentally sustainable agriculture amid escalating environmental challenges.

Digitalization of Colorimetric Sensor Technologies for Food Safety

Colorimetric sensors play a crucial role in promoting on-site testing, enabling the detection and/or quantification of various analytes based on changes in color. These sensors offer several advantages, such as simplicity, cost-effectiveness, and visual readouts, making them suitable for a wide range of applications, including food safety and monitoring. A critical component in portable colorimetric sensors involves their integration with color models for effective analysis and interpretation of output signals. The most commonly used models include CIELAB (Commission Internationale de l'Eclairage), RGB (Red, Green, Blue), and HSV (Hue, Saturation, Value). This review outlines the use of color models via digitalization in sensing applications within the food safety and monitoring field. Additionally, challenges, future directions, and considerations are discussed, highlighting a significant gap in integrating a comparative analysis toward determining the color model that results in the highest sensor performance. The aim of this review is to underline the potential of this integration in mitigating the global impact of food spoilage and contamination on health and the economy, proposing a multidisciplinary approach to harness the full capabilities of colorimetric sensors in ensuring food safety.

Novel intelligent packaging films based on starch/PVA with Cu-ICA nanocrystal as functional compatibilizer for monitoring food freshness

Considering public health and environmental safety, the development of reliable and efficient monitoring methods is essential to ensure food quality and safety. Herein, a new Cu-based metal organic framework (Cu-ICA) nanocrystal with ammonia-sensitive performance was built up and then introduced as a functional compatibilizer of starch/polyvinyl alcohol (STA/PVA) blend to develop high-performance intelligent packaging films for food freshness monitoring. The introduction of Cu-ICA upgraded the compatibility, mechanical strength (42.9 MPa), UV-protection (with UV transmittance of only 2.8 %), and moisture/oxygen barrier performances of STA/PVA film. Furthermore, the developed STA/PVA/Cu-ICA films presented long-term colour stability, outstanding antibacterial efficacy (over 99.5 %) toward both Escherichia coli and Staphylococcus aureus bacteria, as well as remarkable ammonia-sensitive discoloration capability. The STA/PVA/Cu-ICA films possessed visually identifiable colour change during the monitoring of shrimp spoilage. These findings indicate that the developed STA/PVA/Cu-ICA film possesses tremendous potential as an intelligent active packaging material.

Development of smart colorimetric indicators for tracking kimchi freshness by loading aronia extract in agar, κ-carrageenan, and cellulose nanofiber films

Color indicator films incorporating aronia extract powder (AEP) and biopolymers like agar, carrageenan, and cellulose nanofiber (CNF) were developed to monitor kimchi freshness. AEP-containing films showed strong UV-barrier properties, and reduced light transmittance by 99.12 % for agar, 98.86 % for carrageenan, and 98.67 % for CNF-based films. All AEP-films exhibited high sensitivity to pH changes and vapor exposure to ammonia and acetic acid. Color change notably influenced by the polymer type, particularly evident with ammonia vapor exposure, especially in the AEP/carrageenan film. The chemical structure and thermal stability of the biopolymers remained unchanged after AEP-addition. Tensile strength increased by 24.2 % for AEP/CNF but decreased by 19.4 % for AEP/agar and 24.3 % for AEP/carrageenan films. AEP-containing films displayed strong antioxidant activity, with 99 % free radical scavenging in ABTS and ~ 80 % in DPPH assays. Alkalized AEP-indicator films were more effective in detecting color changes during kimchi packaging tests. Among the labels, alkalized AEP/agar film showed the most obvious color change from green-gray (fresh kimchi, pH 5.5, acidity 0.48 %) to pale brown (optimal fermentation, pH 4.6, acidity 0.70 %), and pale violet-brown (over-fermented, pH 3.80, acidity 1.35 %). Alkalized AEP-indicator films offer promising real-time detection of packed fermented foods like kimchi.

Development of amine-sensitive intelligent film with MIL-100(Fe) as function filler based on anthocyanins/pectin for monitoring chilled meat freshness

To enhance the amine-sensitivity of intelligent films for accurate monitoring of chilled meat freshness, different additions (0, 1, 2, 3 wt%) of MIL-100(Fe) were incorporated into the matrix composed of anthocyanins (ANs) and pectin (P). Results indicated that the tensile strength, thermal stability, barrier performance and absorption capacity of the films with MIL-100(Fe) were improved significantly (p < 0.05). Especially, the film with 2 % MIL-100(Fe) exhibited the best performance due to its compact structure and the highest crystallinity. Additionally, adsorption isotherms of the films with MIL-100(Fe) were fitted on the Langmuir and the Freundlich isotherm, and adsorption kinetics were fitted on the pseudo-second-order model and Elovich model, respectively (R2 > 0.96), suggesting a combined mechanism of chemisorption and intraparticle diffusion. Besides, when the films were exposed in ammonia environment, they changed color from purple to blue-violet, finally to green. Ultimately, film with 2 % MIL-100(Fe) was used to monitor the chilled meat freshness, as expected, similar color variation was observed at three stages of meat freshness (fresh, sub-fresh, and spoiled), which enabled the accurate differentiation of meat freshness. Thus, films with MIL-100(Fe) demonstrated the potential to be amine-sensitive intelligent packaging for monitoring chilled meat freshness in real time.

Novel chitosan-based smart bio-nanocomposite films incorporating TiO2 nanoparticles for white bread preservation

Chitosan (CS)-based bio-nanocomposite food packaging films were prepared via solvent-casting method by incorporating a unique combination of additives and fillers, including polyvinyl alcohol (PVA), glycerol, Tween 80, castor oil (CO), and nano titanium dioxide (TiO2) in various proportions to enhance film properties. For a comprehensive analysis of the synthesized films, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), tensile testing, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and UV-vis spectrophotometry were employed. Furthermore, the antimicrobial efficacy of the films against S. aureus, E. coli, and A. niger was examined to assess their potential to preserve food from foodborne pathogens. The results claimed that the inclusion of castor oil and TiO2 nanoparticles considerably improved antimicrobial properties, UV-vis light barrier properties, thermal stability, optical transparency, and mechanical strength of the films, while reducing their water solubility, moisture content, water vapor and oxygen permeability. Based on the overall analysis, CS/PVA/CO/TiO2-0.3 film can be selected as the optimal one for practical applications. Furthermore, the practical application of the optimum film was evaluated using white bread as a model food product. The modified film successfully extended the shelf life of bread to 10 days, surpassing the performance of commercial LDPE packaging (6 days), and showed promising attributes for applications in the food packaging sector. These films exhibit superior antimicrobial properties, improved mechanical strength, and extended shelf life for food products, marking a sustainable and efficient alternative to conventional plastic packaging in both scientific research and industrial applications.

Ammonia-responsive chitosan/polymethacrylamide double network hydrogels with high-stretchability, fatigue resistance and anti-freezing for real-time chicken breast spoilage monitoring

Hydrogels are a promising option for detecting food spoilage in humid conditions, but current indicators are prone to mechanical flaws, posing a concern for packaging systems that require strong mechanical properties. Herein, a double network hydrogel was prepared by polymerizing methacrylamide in a chitosan system with aluminum chloride and glycerol. The resulting hydrogel demonstrated high stretchability (strain >1500 %), notch insensitivity, excellent fatigue resistance, and exceptional anti-freezing capabilities even at -21 °C. When incorporating bromothymol blue (BB) or methyl red (MR), or mixtures of these dyes into the hydrogels as indicators, they exhibited sensitive colorimetric responses to pH and NH3 levels at different temperatures. Hydrogels immobilizing BB to MR ratios of 1:1 and 1:2 displayed clearer and more sensitive color responses when packed into chicken breast, with a sensitivity level of 1.5 ppm of total volatile basic nitrogen (TVB-N). This color response correlated positively with the accumulation of TVB-N on the packaging during storage at both 25 °C and 4 °C, providing sensitive indications of chicken breast deterioration. Overall, the developed hydrogels and indicators demonstrate enhanced performance characteristics, including excellent mechanical strength and highly NH3-sensitive color responses, making significant contributions to the food spoilage detection and intelligent packaging systems field.

Development of innovative active packaging films using gelatin/pullulan-based composites incorporated with cinnamon essential oil-loaded metal-organic frameworks for meat preservation

This study aimed to investigate the effect of cinnamon essential oil (CEO)-loaded metal-organic frameworks (CEO@MOF) on the properties of gelatin/pullulan (Gel/Pull)-based composite films (Gel/Pull-based films). The incorporation of CEO@MOF into Gel/Pull-based films demonstrated significant antimicrobial activity against S. aureus, S. enterica, E. coli, and L. monocytogenes. Additionally, CEO@MOF integrated film exhibited a 98.16 % ABTS radical scavenging, with no significant change in the mechanical properties of the neat Gel/Pull film. The UV blocking efficiency of the composite films increased significantly from 81.38 to 99.56 % at 280 nm with the addition of 3 wt% CEO@MOF. Additionally, Gel/Pull/CEO@MOF films effectively extended the shelf life of meat preserved at 4 °C by reducing moisture loss by 3.35 %, maintaining the pH within the threshold limit (6.2), and inhibiting bacterial growth by 99.9 %. These results propose that CEO@MOF has significant potential as an effective additive in active packaging to improve shelf life and food safety.

Novel Tannic Acid-Modified Cobalt-Based Metal-Organic Framework: Synthesis, Characterization, and Antimicrobial Activity

Metal-organic frameworks (MOFs) are a class of hybrid inorganic-organic materials with typical porous structures and a unique morphology. Due to their diversity, they are extensively used in a wide range of applications such as environmental, catalysis, biomedicine, etc. In this study, a novel cobalt-based MOF modified with tannic acid (Co-TPA/TA) (TPA: terephthalic acid; TA: tannic acid) as a promising material for antimicrobial agents was synthesized and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, and thermogravimetric analysis and compared with an as-synthesized cobalt-based framework. Co-TPA/TA demonstrated good antimicrobial efficiency under optimum conditions against yeast Candida albicans ATCC 10231, Gram-negative Escherichia coli ATCC 8739, and Gram-positive Staphylococcus aureus ATCC 6538 with an inhibition zone ranging from 14 to 20 mm. Reduced ATP levels, generation of reactive oxygen species, membrane damage from cobalt ion release, and development of an alkaline microenvironment could all be contributing factors to the possible antimicrobial pathways. The novel framework can be obtained using simple, affordable, and easily accessible commercial ligands and is considered to have the potential to be used as an antimicrobial material in the future.

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.

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.

Essential oil-loaded biopolymeric particles on food industry and packaging: A review

Essential oils (EOs) are liquid extracts derived from various parts of herbal or medicinal plants. They are widely accepted in food packaging due to their bioactive components, which exhibit remarkable antioxidant and antimicrobial properties against various pathogenic and food spoilage microorganisms. However, the functional efficacy of EOs is hindered by the high volatility of their bioactive compounds, leading to rapid release. Combining biopolymers with EOs forms a complex network within the polymeric matrix, reducing the volatility of EOs, controlling their release, and enhancing thermal and mechanical stability, favoring their application in food packaging or processing industries. This study presents a comprehensive overview of techniques used to encapsulate EOs, the natural polymers employed to load EOs, and the functional properties of EOs-loaded biopolymeric particles, along with their potential antioxidant and antimicrobial benefits. Additionally, a thorough discussion is provided on the widespread application of EOs-loaded biopolymers in the food industries. However, research on their utilization in confectionery processing, such as biscuits, chocolates, and others, remains limited. Further studies can be conducted to explore and expand the applications of EOs-loaded biopolymeric particles in food processing industries.

Gelatin nanofibers with black elderberry, Au nanoparticles and SnO2 as intelligent packaging layer used for monitoring freshness of Hake fish

The electrospun gelatin nanofibers containing black elderberry (BE) extract, Au nanoparticles (AuNPs) and SnO2 were fabricated as intelligent packaging layer for Hake fish (Merluccius merluccius) fillets. Image analysis confirmed the formation of continuous ultrafine fibers. Differences between nanofibers were evaluated in terms of thermal stability, and chemical composition during storage. Fourier transform infrared spectrums indicated strong bonding interactions between gelatin and other compounds. Thermal analysis results showed that the addition of AuNPs contributed to the thermal stabilization of the gelatin chain. L, a, and b values of nanofibers were also measured. A rapid color change occurred after exposure to volatiles with the highest difference in L (52.29 %) of the sample containing gelatin, BE, SnO2 and AuNPs (p < 0.05). This study showed that the absorption of volatiles on nanofibers can be detected from color changes of nanofibers. The outcomes of this study can be applied for intelligent packaging layer in seafood products.

Biodegradable bio-film based on Cordyceps militaris and metal-organic frameworks for fruit preservation

In this study, Cordyceps militaris matrix was employed for the first time to fabricate a biodegradable food packaging. Carmine and Ag@CuBTC were introduced to cross-link with mycelium and were uniformly dispersed within the matrix to enhance the water resistance, antimicrobial, and antioxidant properties of the bio-films. The bio-film displayed high biodegradability, with nearly 100 % degradation achieved after three weeks. The bio-film exhibited exceptional resistance to oxidation (49.30 % DPPH and 93.94 % ABTS•+), as well as effective inhibitory capabilities against E. coli and S. aureus, respectively. The composite film maintained a high CO2/O2 selective permeability, which was advantageous for mitigating fruit metabolism and extending shelf life. Simultaneously, food preservation experiments confirmed that these bio-films can decelerate the spoilage of fruits and effectively prolong the shelf-life of food. The experimental findings indicated that the prepared Bio-R-Ag@Cu film held promise as an environmentally friendly biodegradable material for food packaging.

Methylcellulose/chitosan nanofiber-based composites doped with lactoferrin-loaded Ag-MOF nanoparticles for the preservation of fresh apple

Increasing demand for high-quality fresh fruits and vegetables has led to the development of innovative active packaging materials that exhibit controlled release of antimicrobial/antioxidant agents. In this study, composite biopolymer films consisting of methylcellulose (MC) and chitosan nanofibers (ChNF) were fabricated, which contained lactoferrin (LAC)-loaded silver-metal organic framework (Ag-MOF) nanoparticles. The results indicated that the nanoparticles were uniformly distributed throughout the biopolymer films, which led to improvements in tensile strength (56.1 ± 3.2 MPa), thermal stability, water solubility, swelling index, water vapor barrier properties (from 2.2 ± 2.1 to 1.9 ± 1.9 × 10-11 g. m/m2. s. Pa), and UV-shielding effects. The Ag-MOF-LAC2% films also exhibited strong and long-lasting antibacterial activity against E. coli (19.8 ± 5.2 mm) and S. aureus (20.1 ± 3.2 mm), which was attributed to the slow release of antimicrobial LAC from the films. The composite films were shown to maintain the fresh appearance of apples for at least seven days, which was attributed to their antimicrobial and antioxidant activities. Consequently, these composite films have the potential in the assembly of innovative active packaging materials for protecting fresh fruits and vegetables. However, further work is required to ensure their safety and economic viability.

Recent advances in carboxymethyl cellulose-based active and intelligent packaging materials: A comprehensive review

Researchers have concentrated on innovative approaches to increase the shelf life of perishable food products and monitor their quality during storage and transportation as consumer demand for safe, environmentally friendly, and effective packaging develops. This comprehensive review aims to provide an overview of recent developments in carboxymethyl cellulose (CMC) chemical synthesis and its applications in active and intelligent packaging materials. It explores various methods for modifying cellulose to produce CMC and highlights the unique properties that make it suitable for addressing packaging industry challenges. The integration of CMC into active packaging systems, which helps reduce food waste and enhance food preservation, is discussed in depth. Furthermore, the integration of CMC in smart sensors and indicators for real-time monitoring and quality assurance in intelligent packaging is examined. The chemical synthesis of CMC and strategies to optimise its properties were studied, and the review concluded by examining the challenges and prospects of CMC-based packaging in the industry. This review is intended to serve as a valuable resource for researchers, industry professionals, and policymakers interested in the evolving landscape of CMC and its role in shaping the future of packaging materials.

Smart packaging films based on corn starch/polyvinyl alcohol containing nano SIM-1 for monitoring food freshness

There is at present an acute need for the construction of biopolymer-based smart packaging material that can be applied for the real-time visual monitoring of food freshness. Herein, a nano-sized substituted imidazolate material (SIM-1) with ammonia-sensitive and antibacterial ability was effectively manufactured and then anchored within corn starch/polyvinyl alcohol (CS/PVA) blend to construct biopolymeric smart active packaging material. The structure, physical and functional performances of CS/PVA-based films with different content of SIM-1 (0.5, 1.0 and 2.0 wt% on CS/PVA basis) were then explored in detail. Results revealed that the incorporated SIM-1 nanocrystals were equally anchored within the CS/PVA matrix owing to the establishment of potent hydrogen-bonding interactions, which produced an obvious improvement in the compatibility of CS/PVA blend film, as well as its mechanical strength, water/oxygen barrier and UV-screening performances. The constructed CS/PVA/SIM-1 blend films further demonstrated superior long-term color stability property, ammonia-sensitive and antibacterial functions. Furthermore, the CS/PVA/SIM-1 blend films were utilized for effectively monitoring the deterioration of shrimp via observable color alteration. The above findings suggested the potential applications of CS/PVA/SIM-1 blend films in smart active packaging.

Fabrication of a colorimetric film based on bacterial cellulose/metal coordination framework composite for monitoring food spoilage gas

A newly designed colorimetric sensing film has been developed to determine the spoilage gas from food deterioration. The fabrication of sensing film used for food labels based on bacterial cellulose and carboxymethyl cellulose composite film (BC/CMC) incorporated with Bis(imidazolium) tetrachlorocuprate, HIm2CuCl4 was focused. The BC/CMC composite films were prepared by vacuum filtration and then dipped into the (5-20 % w/w) HIm2CuCl4 solution. Subsequently, they were dried at 60 °C to obtain the BC/CMC-Cu film. For monitoring fish freshness, the TVB-N level was considered an indicator of determining fish spoilage. In addition, the color change was evaluated and expressed as Lab color values and total color difference (TCD). According to the sensing response, the TCD values of the sensing films had continuously changed, corresponding to the ammonia gas, which is one of the TVB-N gases. Based on the variations in Lab color values exposed to ammonia gas at room temperature, the film color shifted from the initial lime green color to the final blue color due to the substitution of metal-ligand bonding. Finally, this colorimetric sensing film can be employed as a potential food freshness indicator in intelligent packaging.

Multi-functional nanocellulose based nanocomposites for biodegradable food packaging: Hybridization, fabrication, key properties and application

Nowadays, non-degradable plastic packaging materials have caused serious environmental pollution, posing a threat to human health and development. Renewable eco-friendly nanocellulose hybrid (NCs-hybrid) composites as an ideal alternative to petroleum-based plastic food packaging have been extensively reported in recent years. NCs-hybrids include metal, metal oxides, organic frameworks (MOFs), plants, and active compounds. However, no review systematically summarizes the preparation, processing, and multi-functional applications of NCs-hybrid composites. In this review, the design and hybridization of various NCs-hybrids, the processing of multi-scale nanocomposites, and their key properties in food packaging applications were systematically explored for the first time. Moreover, the synergistic effects of various NCs-hybrids on several properties of composites, including mechanical, thermal, UV shielding, waterproofing, barrier, antimicrobial, antioxidant, biodegradation and sensing were reviewed in detailed. Then, the problems and advances in research on renewable NCs-hybrid composites are suggested for biodegradable food packaging applications. Finally, a future packaging material is proposed by using NCs-hybrids as nanofillers and endowing them with various properties, which are denoted as "PACKAGE" and characterized by "Property, Application, Cellulose, Keen, Antipollution, Green, Easy."

Multifunctional food packaging materials: Lactoferrin loaded Cr-MOF in films-based gelatin/κ-carrageenan for food packaging applications

In this study, antimicrobial biocomposite films based on gelatin-κ-carrageenan (Gκ) with 1, 2 and 4 % lactoferrin (L) loaded chromium-based metal-organic frameworks (L@Cr-MOFs) nanoparticles were synthesized by casting methods. The addition of L loaded Cr-MOFs into Gκ based films increased elongation at break from 2.19 to 14.92 % and decreased the tensile strength from 65.1 to 31.22 MPa. L@Cr-MOFs addition reduced swelling index (from 105 to 70.8 %), water solubility (from 61.3 to 34.63 %) and water vapor permeability (from 2.46 to 2.19 × 10-11 g. m/m2. s). When the additional amount was 4 wt%, the Gκ/L@Cr-MOFs films showed antibacterial effects against Escherichia coli and Staphylococcus aureus with the inhibition zone of 19.7 mm and 20.2 mm, respectively. In addition, strawberries preservation trial shown that the Gκ/L@Cr-MOFs films delayed the growth of spoilage molds on the surface of fruits. This research indicated that Gκ/L@Cr-MOFs are promising active packaging materials for the preservation of perishable fruits.

Ammonia-sensitive cellulose acetate-based films incorporated with Co-BIT microcrystals for smart packaging application

Nowadays, there is an increasing demand for smart packaging materials capable of effectively monitoring the food freshness. In this study, new Co-based MOF (Co-BIT) microcrystals with ammonia-sensitivity and antibacterial function were constructed and then loaded within cellulose acetate (CA) matrix to create smart active packaging materials. The influences of Co-BIT loading upon structure, physical, and functional properties of the CA films were then thoroughly explored. It was observed that microcrystalline Co-BIT was uniformly integrated inside CA matrix, which caused significant promotions in mechanical strength (from 24.12 to 39.76 MPa), water barrier (from 9.32 × 10^-6 to 2.73 × 10^-6 g/m·h·Pa) and ultraviolet light protection performances of CA film. Additionally, the created CA/Co-BIT films displayed striking antibacterial efficacy (>95.0 % for both Escherichia coli and Staphylococcus aureus), favorable ammonia-sensitivity function as well as color stability. Finally, the CA/Co-BIT films were successfully applied for indicating the spoilage of shrimp through discernible color changes. These findings suggest that Co-BIT loaded CA composite films have great potential for use as smart active packaging.

Current Applications of Bionanocomposites in Food Processing and Packaging

Nanotechnology advances are rapidly spreading through the food science field; however, their major application has been focused on the development of novel packaging materials reinforced with nanoparticles. Bionanocomposites are formed with a bio-based polymeric material incorporated with components at a nanoscale size. These bionanocomposites can also be applied to preparing an encapsulation system aimed at the controlled release of active compounds, which is more related to the development of novel ingredients in the food science and technology field. The fast development of this knowledge is driven by consumer demand for more natural and environmentally friendly products, which explains the preference for biodegradable materials and additives obtained from natural sources. In this review, the latest developments of bionanocomposites for food processing (encapsulation technology) and food packaging applications are gathered.