Biobased Intelligent Food-Packaging Materials with Sustained-Release Antibacterial and Real-Time Monitoring Ability

Development of PVA-chitosan based smart packaging with the addition of red cabbage (Brassica Oleracea Var. capitata F. rubra) anthocyanin extract and copper-based metal-organic material (Cu-Mof)

Naturally-based smart packaging has emerged as an innovative solution to enhance product quality, safety, and shelf life in the food industry. pH-responsive smart packaging based on PVA/Chitosan was developed by incorporating Copper Metal-Organic Frameworks (Cu-MOF) and anthocyanin from red cabbage (Brassica oleracea). The pH-sensitive anthocyanin enables real-time detection of food freshness through color changes. At the same time, combining PVA/Chitosan with Cu-MOF enhances the packaging's mechanical properties, antimicrobial activity, and biodegradability. The results showed that this packaging could undergo pH-dependent color changes across various pH conditions (pH 2 to pH 9), exhibited good mechanical properties (reaching 9.82 MPa with the addition of 1 g of chitosan), and that these mechanical properties were also influenced by the addition of Cu-MOF, which had an average particle size of 1.06 nm. Moreover, the packaging achieved up to 90.38 % biodegradation by adding 1 g of chitosan at pH 3 and 80.43 % at pH 4 within 15 days, making it an environmentally friendly solution. Additionally, this packaging effectively inhibited bacterial growth after incubation, improving food safety. This packaging extended the product's shelf life in food packaging experiments using shrimp. Thus, developing this packaging offers significant potential as an innovative solution in the sustainable food packaging industry, as it is expected to visualize food changes before consumption, extend food shelf life, and significantly reduce food waste issues.

Green fabrication of antimicrobial film for food preservation by polysaccharides from Poria Cocos

Recently, polysaccharide-based film materials have attracting widespread attentions due to their safety, biodegradability, and film-forming properties. However, the limited UV resistance, antibacterial and mechanical properties of polysaccharides severely restrict their applications in food packaging. This work developed a biocomposite film (PGF@Ag) consited of a natural β-glucan from Poria Cocos (PCPA), in-situ synthesized AgNPs and glycerol, showing good antibacterial and antioxidant properties as well as biocompatibility and mechanical properties. Poria Cocos is an edible traditional Chinese medicine, and its residue is rich in polysaccharide. In this system, the large amont of hydrogen groups on PCPA help fast reduce Ag+ to Ag0 in alkalescent solution and the triple-helix conformation of PCPA hinder the aggregation of AgNPs, leading to the ultra small size with 9.0-12.3 nm as well as better ABTS radical scavenging rates of 93.30 ± 0.13 %. Additionally, the hydrogen bonding interactions between glycerol and polysaccharides significantly enhance the mechanical properties of the PGF@Ag films. The tensile strength is measured at 5.94 ± 0.5 MPa, while the elongation at break reaches 128.77 ± 12.45 %, and the Young's modulus is recorded at 15.75 ± 1.91 MPa. Finally, the resulting films exhibited excellent preservation effects on grapes, as reduced weight loss reduction of 14 %, and hardness reduction of approximately 5.2 % over 12 days. This work provides a new strategy of the sustainable construction of antibacterial films, showing great potentials in food preservation and packaging applications.

Carbon dots embedded carrageenan based compostable functional packaging films with barrier bio-coating for prawns freshness monitoring

Biopolymer based intelligent packaging films with barrier properties are gaining significant attention in the food industry due to the compostability, food freshness monitoring potential and shelf life increment capability. In this work, ∼10 nm sized urea- dithiosalicilic acid based carbon dots (UCDs) with aggregation-induced emission (AIE) property are prepared and incorporated into carrageenan biopolymer to develop amine sensing packaging material. Composite film is coated with zein-stearic acid (Z/SA) mixture to improve the water barrier property with water vapour transmission rate value ≤40 g/(m2.day). The coated composite film (CAR3UCD-C) exhibited ammonia sensing capability with a limit of detection (LOD) of 0.6 μM and showed good free radical scavenging activity (70 % against ABTS radicals), high UV blocking property (∼92 % reduction) as well as antibacterial activity against E. coli and S. aureus. The developed films showed better tensile strength (>50 MPa) and good thermal stability (till 200 °C). The material effectively distinguished the freshness states of prawns through fluorescent color change from orange to blue upon spoilage. The coated film is completely degradable in soil within 35 days under ambient conditions. This film can be utilised as a promising intelligent barrier packaging material for monitoring real-time freshness of prawns and other protein-rich foods.

In situ growth of defective ZIF-8 on TEMPO-oxidized cellulose nanofibrils for rapid response release of curcumin in food preservation

Uncontrolled release of active agents in active packaging reduces antimicrobial efficacy, hindering the effective protection of perishable products from microbial infection. Herein, a novel defective engineering was proposed to design defective and hollow ZIF-8 structures grown on TEMPO oxidized cellulose nanofibrils (TOCNFs) and use them as fast-reacting nanocarriers for loading and controlled release curcumin (Cur) in sodium alginate (SA) active packaging systems (CZT-Cur-SA). By employing stable chelation between tannic acid (TA) and ZIF-8 zinc ions, the connections between zinc ions and imidazole ligands were severed to form a loose and hollow structure, which facilitates the rapid reaction and release of active ingredients triggered by pH changes in the microenvironment. Kinetic tests showed CZT-Cur-SA films released 65.68 % of Cur at pH 6.0 within 24 h, compared to 28.26 % at pH 7.0. These films demonstrated exhibited excellent mechanical properties, antioxidation capacity (82.59 %), reinforced moisture (0.51 × 10-10 g m-1 s-1 Pa-1) and satisfied antimicrobial effects on E. coli (1.69 %) and S. aureus (0.88 %). The optimized CZT-Cur-SA film extended strawberry shelf life to at least 7 days under ambient conditions. Our findings introduce a promising approach to designing responsive, biodegradable active packaging for enhanced food safety.

Functional pH-sensitive film based on pectin and whey protein for grape preservation and shrimp freshness monitoring

A pH-sensitive film was prepared from pectin (P) and whey protein (W), incorporating anthocyanin-rich purple sweet potato extract (PPE) as the pH indicator. The effect of PPE content on the structure and properties of the films and the pH indicating function were determined and evaluated for shrimp freshness and grape preservation. The solubility (60.23 ± 7.36 %) and water vapor permeability (0.15 ± 0.04 × 10-11 g·cm/(cm2·s·Pa)) of the pectin/whey protein/PPE (PW-PPE) film with 500 mg/100 mL PPE were the lowest of the films tested and much lower than PW films without PPE. PW-PPE films were non-cytotoxic and had excellent biodegradability in soil. Grapes coated with PW-PPE film had reduced weight loss from water evaporation, and decay during storage was inhibited. The total color change (ΔE) of the PW-PPE films had a strong linear correlation with the pH of shrimps during storage. PW-PPE films have application potential to monitor the real-time freshness of meat and extend the shelf life of fruit.

Innovative applications of bio-inspired technology in bio-based food packaging

Traditionally, food packaging was used to extend the shelf life of food or to monitor its condition. Inspired by many biological structures found in nature, bio-inspired functional materials for bio-based food packaging have been shown to have significantly improved capabilities over traditional bio-based food packaging materials in various aspects and to attract consumers through novel freshness preservation features. This review synthesizes recent advances in bio-inspired bio-based food packaging materials that mimic the structure of natural organisms with specific functionalities, with examples of specific biomimetics in different enhancement areas. In general, bio-based materials have certain disadvantages compared to polymer materials, so there is an urgent need for improvement and enhancement in many areas. Biomimicry further inspires the realization of enhancing some basic functions of bio-based materials for packaging (hydrophobicity, mechanical strength, antimicrobial properties, optical properties) and endowing bio-based materials with more new responsiveness and other functions. What is more interesting is that the inspiration of bionics is taken from nature, and such a perspective can also promote further progress and innovation of bio-based food packaging materials.

The latest research progress on polysaccharides-based biosensors for food packaging: A review

In recent years, polysaccharide-based biosensors have emerged as promising technologies for intelligent food packaging, offering innovative solutions to enhance food quality and safety. This review highlights advancements in designing, developing, and applying these biosensors, particularly those utilizing polysaccharides such as chitosan, cellulose and alginate. Engineered with nanomaterials like ZnO, silver, and carbon nano-tubes demonstrated high sensitivity in real-time monitoring of food spoilage indicators, including pH changes, volatile nitrogen compounds and microbial activity. We discuss the electrochemical properties of these biosensors, highlighting how the integration of electrochemical methods significantly improves their detection capabilities within packaging environments, leading to sensor sensitivity enhancement, greater accuracy, and spoilage detection, ultimately extending the shelf life of perishable food products. Additionally, the review addresses the practical challenges of industrial implementation and explores future research directions for optimizing sensor functionality and scalability. The findings underscore the potential of polysaccharide-based intelligent packaging as a sustainable and effective alternative to conventional methods, paving the way for broader commercial adoption.

A cellulose-based light-management film incorporated with benzoxazine resin/tannic acid exhibiting UV/blue light double blocking and enhanced mechanical property

Cellulose, as a biomass resource, has attracted increasingly attention and extensive research by virtue of its widely sources, ideal degradability, good mechanical properties and easy modification due to its rich hydroxyl groups. Nevertheless, it is still a challenge to attain high performance cellulose-based composite film materials with diverse functional combinations. In this work, we developed a multifunctional cellulose-based film via a facile impregnation-curing strategy. Here, benzoxazine resin (BR) is used as an optically functional component to endow the microfibrillated cellulose (MFC) film with powerful light management capabilities including UV and blue light double shielding, high transmittance, and high haze. Meanwhile, the introduction of tannic acid (TA) substantially enhanced the mechanical properties of the film, including tensile strength and toughness, by constructing energy-sacrificial bonds. An effective self-healing of the film was achieved by controlling the degree of BR curing. The final films exhibited 98.24 % UV shielding and 89.98 % blue light blocking, good mechanical properties including a tensile strength of 202.21 MPa and tensile strain of 7.1 %, as well as desirable thermal healing properties supported by incompletely cured BR. This work may provide new insights into the high-value utilization of biomass resources.

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.

Carrageenan-based functional films hybridized with carbon dots and anthocyanins from rose petals for smart food packaging applications

Multifunctional smart biopolymeric films were fabricated using rose petal anthocyanin (RPA) and carrageenan (CAR) doped with rose petal-derived carbon dots (RP-CDs). Response surface-optimized RPA showed the highest total anthocyanins and radical scavenging ability. Produced RP-CD exhibited UV absorption and high fluorescence with antibacterial/antioxidant abilities. Enrichment with 2 % RP-CD and 5 % RPA in the CAR matrix results in improved physicochemical, i.e., water contact angle, water vapor permeability, and UV-blocking properties of the fabricated material. Results showed that nanocomposite films scavenged radicals better than the neat CAR films. Zeta potential, FTIR, SEM, and XPS suggested improved compatibility/stability and enhanced elemental configuration of RP-CDs/RPA additives in the CAR polymer matrix. Perishable food packaging (minced pork and shrimp) demonstrated that nanocomposite films work efficiently and non-destructively and are promising tools for monitoring real-time freshness through interpretable visual changes from red to yellow. The CAR/RP-CDs/RPA-based nanocomposite indicator films are expected to be applied as various smart packaging materials. These films possess the ability to promptly detect changes in quality, preserve the quality, and prolong the shelf life of packaged foods.

Coconut husk-lignin derived carbon dots incorporated carrageenan based functional film for intelligent food packaging

Carbon dots (CDs) derived from sustainable natural feed-stocks like lignin have gained wide acceptance by virtue of their renewability and promising potential in intelligent sensing applications. The precursor lignin is isolated from agro-biomass waste, coconut husk through sodium hydroxide based extraction process. CDs are synthesised from amine functionalized lignin through solvothermal process and integrated into carrageenan biopolymer matrix (1, 2 and 3 wt%). The composite film with 2 wt% CDs (CARR2CD) showed optimum fluorescent emission intensity, excellent pH dependent fluorescent color change in the food pH range, reasonable tensile strength (46.50 ± 1.32 MPa) and 27 % increase in elongation at break. CDs imparted UV-light blocking properties (70 % UV-light) and enhanced hydrophobicity of the carrageenan matrix. CARR2CD film showed 84 % visible light transparency, 79 % reduction in oxygen transmittance rate (OTR), 81 % reduction in CO2 gas permeability and excellent antioxidant and antibacterial properties (against E. coli and S. aureus). As a practical application, the developed responsive packaging material is used to track pH change associated with milk spoilage via noticeable color change in fluorescent emission of the composite film. Thus, the developed responsive composite film paves a way for use as green and sustainable transparent intelligent food packaging material.