Improving the functionality of biodegradable food packaging materials via porous nanomaterials

Chitosan/PVA composite film enhanced by ZnO/lignin with high-strength and antibacterial properties for food packaging

This study aims to develop a chitosan/polyvinyl alcohol (CS/PVA) composite film (QZCS/PVA) for food packaging, enhanced by the incorporation of quaternary ammonium lignin/ZnO nanoparticles (QAL/ZnO) to improve its antibacterial, antioxidant, and mechanical properties. The QAL/ZnO nanoparticles were synthesized using a co-precipitation method, resulting in a synergistic effect that enhances the uniformity and stability of the composite film. The double cross-linked CS/PVA composite film containing QAL/ZnO nanoparticles effectively mitigates the brittleness of pure chitosan films, achieving a tensile strength of 95.89 MPa. Crucially, the inclusion of QAL/ZnO imparts exceptional antioxidant and antibacterial properties to the QZCS/PVA composite film. Disk diffusion assays revealed markedly enhanced antibacterial efficacy against Staphylococcus aureus and Escherichia coli in comparison to analogous biopolymer films. The dense network structure of the composite film also provides excellent water resistance, which contributes to extending the shelf life of food products. In a 12-day grape preservation experiment, the composite film exhibited outstanding preservation performance. These results underscore the potential of the CS/PVA composite film containing lignin and chitosan for food packaging applications, offering significant advantages in improving food preservation.

Unlocking the potential of green-engineered carbon quantum dots for sustainable packaging biomedical applications and water purification

Carbon quantum dots (CQDs) with well-defined architectures offer highly fascinating properties such as excellent water-solubility, exceptional luminescence, large specific surface area, non-toxicity, biocompatibility and tuneable morphological, structural, and chemical features. This review comprehensively overviews recent breakthroughs and critical milestones in the green synthesis of CQDs from renewable sources and provides guidance for their sustainable development towards fulfilling the goals of green chemistry. It also discusses the interaction of CQDs with various biopolymers to improve the material performance and functionality. This paper also highlights the latest technological applications of CQDs in numerous fields, including sustainable packaging, biosensing, bioimaging, cancer therapy, drug delivery as well as water purification. Finally, it summarizes the main challenges and provides an outlook on the future directions of CQDs in packaging and biomedical fields. This review can act as a roadmap to guide researchers for tailoring the properties of CQDs for important composite and biomedical fields.

Two-Dimensional Nanomaterials for Polymer-Based Packaging Applications: A Colloidal Perspective

The integration of two-dimensional (2D) nanomaterials into polymer-based packaging presents a promising avenue for sustainable, high-performance materials. This perspective explores the roles of colloidal interactions in the assembly of 2D materials into thin films for packaging applications. We begin by analyzing the types of colloidal forces present in 2D nanomaterials and their impact on dispersion and stability. We then explore how these colloidal forces can be modulated through chemical structure, ionic intercalation, and shear forces, influencing the stacking behavior and orientation of 2D materials within the films. The incorporation of these 2D materials into polymer-based packaging systems is also considered, with a focus on how surface functionalization and dispersion techniques enhance their interaction with the polymer matrix to improve barrier properties against gases and moisture, increase mechanical strength, and impart antimicrobial effects. This work underscores the critical role of colloidal interactions in optimizing the design and performance of 2D-nanomaterial-based packaging for sustainable development.

Food packaging solutions in the post-per- and polyfluoroalkyl substances (PFAS) and microplastics era: A review of functions, materials, and bio-based alternatives

Food packaging (FP) is essential for preserving food quality, safety, and extending shelf-life. However, growing concerns about the environmental and health impacts of conventional packaging materials, particularly per- and polyfluoroalkyl substances (PFAS) and microplastics, are driving a major transformation in FP design. PFAS, synthetic compounds with dual hydro- and lipophobicity, have been widely employed in food packaging materials (FPMs) to impart desirable water and grease repellency. However, PFAS bioaccumulate in the human body and have been linked to multiple health effects, including immune system dysfunction, cancer, and developmental problems. The detection of microplastics in various FPMs has raised significant concerns regarding their potential migration into food and subsequent ingestion. This comprehensive review examines the current landscape of FPMs, their functions, and physicochemical properties to put into perspective why there is widespread use of PFAS and microplastics in FPMs. The review then addresses the challenges posed by PFAS and microplastics, emphasizing the urgent need for sustainable and bio-based alternatives. We highlight promising advancements in sustainable and renewable materials, including plant-derived polysaccharides, proteins, and waxes, as well as recycled and upcycled materials. The integration of these sustainable materials into active packaging systems is also examined, indicating innovations in oxygen scavengers, moisture absorbers, and antimicrobial packaging. The review concludes by identifying key research gaps and future directions, including the need for comprehensive life cycle assessments and strategies to improve scalability and cost-effectiveness. As the FP industry evolves, a holistic approach considering environmental impact, functionality, and consumer acceptance will be crucial in developing truly sustainable packaging solutions.

Zeolite Additives for Flexible Packaging Polymers: Current Status Review and Future Perspectives

Zeolites are interesting inorganic additives that could be employed for plastic packaging applications. Polyethylene (PE) and polypropylene (PP) are intensively used for packaging as they provide great performance at low cost, even though they have poor environmental sustainability and may be more valorized. Biodegradable polymers may therefore represent a more eco-friendly alternative, but still, they have limited applications due to their generally inferior properties. Therefore, this review focuses on the use of zeolites as additives for flexible packaging applications to mainly improve the mechanical and barrier properties of PE, PP, and some biodegradable polymers, possibly with antimicrobial and scavenging activities, by exploiting zeolites' cation exchange ability and adsorption properties. Film preparation and characterization have been investigated. The obtained enhancements regard generally higher gas barriers, elastic moduli, and strengths, along with thermal stability. Elongation at break decreased for all PE composites and tended to increase for other matrices. The use of zeolites as additives for polymer films is promising (mainly for biodegradable polymers); still, it requires overcoming some limiting drawbacks associated with the additive concentration and dispersion mainly due to matrix-additive incompatibility.

Thermoplastic starch-ZnO nanocomposites: A comprehensive review of their applications in functional food packaging

The increasing demand for environmentally friendly food packaging solutions has driven extensive research on biodegradable materials, particularly thermoplastic starch (TPS), which is an eco-friendly alternative to petroleum-based plastics. Despite its eco-friendliness, TPS exhibits limitations, including inadequate mechanical and thermal properties, high water sensitivity, and low antibacterial activity. Although strategies such as chemical modification, blending, and compatibilizers have been employed to enhance TPS for functional packaging applications, they often fail to address these fundamental issues. A promising approach involves incorporating zinc oxide (ZnO) nanoparticles, which significantly improve the mechanical strength, thermal stability, and antimicrobial properties of TPS. This review focuses on TPS-ZnO nanocomposites, a notable subcategory of bio-nanocomposites recognized for their enhanced functional properties in food packaging applications. It discusses the synthesis and properties of these nanocomposites, particularly their mechanical, thermal, antimicrobial, and antioxidant properties. Moreover, this review explores the various applications of TPS-ZnO nanocomposites in active, intelligent, and sustainable food packaging, emphasizing their potential to address the pressing challenges of food waste and environmental impact.

Green fabrication of modified lignin/zeolite/chitosan-based composite membranes for preservation of perishable foods

Chitosan, as a kind of naturally occurring green and degradable material for the preservation of perishable foods, was investigated in this study with the objective of enhancing its preservation performances. Herein, lignin was modified using the solvent fractionation method (modified lignin, ML, including ML1-ML3), while natural clinoptilolite zeolite was modified using the alkali modification method (modified clinoptilolite zeolite, MCZ, including MCZ1-MCZ5). After optimizing the conditions, it was discovered that incorporating both ML3 and MCZ3 into pure chitosan-based membranes might be conducive to fabricate chitosan-based composite membranes for the preservation of perishable foods. As-prepared composite membranes possessed better visible light transmittance, antioxidant activity, and carbon dioxide/oxygen selectivity, resulting in improved preservation effects on the model perishable foods such as bananas, cherry tomatoes, and cheeses. These findings might indicate promising applications for chitosan-based composite membranes with modified lignin and zeolite in the field of eco-friendly degradable materials for the preservation of perishable foods.

Water-resistant and barrier properties of poly(vinyl alcohol)/nanocellulose films enhanced by metal ion crosslinking

Polyvinyl alcohol (PVA) is a promising alternative to non-biodegradable flexible packaging materials, and nanocellulose is often used to enhance the properties of PVA films, but the composite films still have poor water resistance and barrier properties. To address this issue, iron ions (Fe3+) were introduced into PVA/cellulose nanofibrils (CNF) films, and Fe3+ formed coordination bonds with carboxyl and hydroxyl groups on the surface of CNF and PVA chains. Therefore, constructing a strong coordination crosslinking network within the film and improving the interfacial interaction between PVA and CNF. The water resistance, mechanical and barrier properties of the crosslinked films were significantly improved. Compared with the un-crosslinked film, the oxygen transmission rate (OTR) was decreased by up to 67 %, and the water swelling ratio was significantly reduced from 1085 % to 352 %. The tensile strength of the film with 1.5 wt% Fe3+ reached 41.93 MPa, which was 62 % higher than that of the un-crosslinked film. Furthermore, the composite film demonstrated good recyclability, almost recovering its original mechanical properties in two recycling tests. This simple and effective method for preparing water resistance and barrier films shows potential applications in flexible packaging areas.

Recent Advances in Hollow Nanostructures: Synthesis Methods, Structural Characteristics, and Applications in Food and Biomedicine

The development and investigation of innovative nanomaterials stand poised to advance technological progress and meet the contemporary demand for efficient, environmentally friendly, and intelligent products. Hollow nanostructures (HNS), characterized by their hollow architecture, exhibit diverse properties such as expansive specific surface area, low density, high drug-carrying capacity, and customizable structures. These elaborated structures, encompass nanospheres, nanoboxes, rings, cubes, and nanowires, have wide-ranging applications in biomedicine, materials chemistry, food industry, and environmental science. Herein, HNS and their cutting-edge synthesis methods, including solvothermal methods, liquid-interface assembly methods, and the self-templating methods are discussed in-depth. Meanwhile, the potential applications of HNS in food and biomedicine such as food packing, biosensor, and drug delivery over the past three years are summarized, together with a prospective view of future research directions and challenges. This review will offer new insights into designing next generation of hollow nanomaterials for food and biomedicine applications.

Progress in food packaging applications of biopolymer-nanometal composites - A comprehensive review

Eco-friendly nanotechnology-enabled biopolymers are one of the novel concepts of packaging materials to substitute traditional synthetic polymers and their composites. This article succinctly reviews the recent developments of introducing additional functionalities to biopolymers using metal and metal oxide nanoparticles. The functionality of metal nanoparticles such as silver, zinc oxide, titanium dioxide, copper oxide, gold, and magnesium oxide, as food packaging materials were discussed. The addition of nanoparticles in biopolymers improves mechanical properties, gas barrier properties, durability, temperature stability, moisture stability, antimicrobial activity, antioxidant property, and UV absorbance and can prevent the presence of ethylene and oxygen, hence extending the shelf life of foodstuffs. Other than this, the functional activity of these biopolymer composite films helps them to act like smart or intelligent packaging. The selection of metal nanoparticles, particle migration, toxicological effect, and potential future scope in the food packaging industry are also reviewed.

Emerging Nano/Microporous Architectures for Food Hazards: New Strategies for Precise Inspection and New Principles for Controllable Regulation

The big progress of materials science along with chemical engineering and biotechnology has significantly promoted interdisciplinary development, achieving advanced analytical methodologies, improved inspection performance, as well as promising regulation principles for food safety. The very recent progress on nano/microporous architectures for agri-food science, including new strategies for precise inspection and new principles for controllable regulation of food hazards, are summarized and discussed. Major attention is paid to the newly emerged porous architectures with their derivative nano/microstructures contributing to food safety through their instinctive advantages including special material surface, extraordinary porous structure, ease-of-modification, and excellent diversity and variability. This review clearly and logically displays the research road maps and development trends for current food safety issues and give suggestive directions for future outlook as well as the bottleneck problems to be solved, not only smart inspection and analysis but also elimination and control of ever-emerging food hazards.

Sustainable strategies for using natural extracts in smart food packaging

The growing demand for sustainable and eco-friendly food packaging has prompted research on innovative solutions to environmental and consumer health issues. To enhance the properties of smart packaging, the incorporation of bioactive compounds derived from various natural sources has attracted considerable interest because of their functional properties, including antioxidant and antimicrobial effects. However, extracting these compounds from natural sources poses challenges because of their complex chemical structures and low concentrations. Traditional extraction methods are often environmentally harmful, expensive and time-consuming. Thus, green extraction techniques have emerged as promising alternatives, offering sustainable and eco-friendly approaches that minimise the use of hazardous solvents and reduce environmental impact. This review explores cutting-edge research on the green extraction of bioactive compounds and their incorporation into smart packaging systems in the last 10 years. Then, an overview of bioactive compounds, green extraction techniques, integrated techniques, green extraction solvents and their application in smart packaging was provided, and the impact of bioactive compounds incorporated in smart packaging on the shelf lives of food products was explored. Furthermore, it highlights the challenges and opportunities within this field and presents recommendations for future research, aiming to contribute to the advancement of sustainable and efficient smart packaging solutions.

Enhanced carbohydrate-based plastic performance by incorporating cerium-based metal-organic framework for food packaging application

The development of biodegradable active packaging films with hydrophobic characteristics is vital for extending the shelf life of food and reducing the reliance on petroleum-based plastics. In this study, novel hydrophobic cerium-based metal-organic framework (Ce-MOF) nanoparticles were successfully synthesized. The Ce-MOF nanoparticles were then incorporated into the cassava starch matrix at varying concentrations (0.5 %, 1.5 %, 3 %, and 4 % w/w of total solid) to fabricate cassava-based active packaging films via the solution casting technique. The influence of Ce-MOF on the morphology, thermal attributes, and physicochemical properties of the cassava film was subsequently determined through further analyses. Biomedical analysis including antioxidant activity and the cellular morphology evaluation in the presence of the films was also conducted. The results demonstrated that the consistent dispersion of Ce-MOF nanofillers within the cassava matrix led to a significant enhancement in the film's crystallinity, thermal stability, antioxidant activity, biocompatibility, and hydrophobicity. The introduction of Ce-MOF also contributed to the film's reduced water solubility. Considering these outcomes, the developed cassava/Ce-MOF films undoubtedly have significant potential for active food packaging applications.

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.

Starch-gelatin blend films: A promising approach for high-performance degradable food packaging

Packaging plays a vital role in safeguarding food from environmental factors and contamination. However, the overuse and improper disposal of non-biodegradable plastic packaging materials have led to environmental concerns and health risks. To address these challenges, the development of degradable food packaging films is crucial. Biodegradable polymers, including natural biopolymers like starch (ST) and gelatin (GE), have emerged as promising alternatives to traditional plastics. This review focuses on the utilization of ST-GE blends as key components in composite films for food packaging applications. We discuss the limitations of pure ST-GE films and explore methods to enhance their properties through the addition of plasticizers, cross-linkers, and nanoparticles. The blending of ST-GE, facilitated by their good miscibility and cross-linking potential, is highlighted as a means to improve film performance. The review also examines the impact of various additives on the properties of ST-GE blend films and summarizes their application in food preservation. By providing a comprehensive overview of ST-GE hybrid systems, this study aims to contribute to the advancement of sustainable and effective food packaging solutions.

Recent advances in qualitative and quantitative characterization of nanocellulose-reinforced nanocomposites: A review

Nanocellulose has received immense consideration owing to its valuable inherent traits and impressive physicochemical properties such as biocompatibility, thermal stability, non-toxicity, and tunable surface chemistry. These features have inspired researchers to deploy nanocellulose as nanoscale reinforcement materials for bio-based polymers. A simple yet efficient characterization method is often required to gain insights into the effectiveness of various types of nanocellulose. Despite a decade of continuous research and booming growth in scientific publications, nanocellulose research lacks a measuring tool that can characterize its features with acceptable speed and reliability. Implementing reliable characterization techniques is critical to monitor the specifications of nanocellulose alone or in the final product. Many techniques have been developed aiming to measure the nano-reinforcement mechanisms of nanocellulose in polymer composites. This review gives a full account of the scientific underpinnings of techniques that can characterize the shape and arrangement of nanocellulose. This review aims to deliver consolidated details on the properties and characteristics of nanocellulose in biopolymer composite materials to improve various structural, mechanical, barrier and thermal properties. We also present a comprehensive description of the safety features of nanocellulose before and after being loaded within biopolymeric matrices.