Grafting Hollow Covalent Organic Framework Nanoparticles with Thermal-Responsive Polymers for the Controlled Release of Preservatives

Preparation and characterization of a starch-based active packaging with pH-sensitive release via tea tree essential oil loaded in a covalent organic framework

Tea tree oil (TTEO) is a natural active agent, but less stable. In this research, a covalent organic frameworks, CTB, is prepared, and used to load TTEO (CTB@TTEO), and then CTB@TTEO as the filler is used to prepare starch-based active packaging films for storage blueberries. The results show that CTB@TTEO could increase the mechanical strength, gas barrier, antioxidant activity, and bacteriostatic activity of the thermoplastic starch film. The starch-based active packaging film with 2 wt% CTB@TTEO possesses the superior preservation effect on blueberry fruits. It is due to that the starch-based active packaging film with 2 wt% CTB@TTEO has the most compact structure, and displays outstanding bacteriostatic activity for Staphylococcus aureus and Escherichia coli. In addition, CTB@TTEO exhibits a pH-sensitive release characteristics. The release dynamics of TTEO in CTB@TTEO conform Avrami models. Consequently, the starch-based active packaging with 2 wt% CTB@TTEO has a promising application potential for fruit preservation.

Recent Advances in Polysaccharide-Based Nanocomposite Films for Fruit Preservation: Construction, Applications, and Challenges

With the constantly escalating demand for safe food packaging, the utilization of biodegradable polysaccharide-based nanocomposite films is being explored as an alternative to traditional petrochemical polymer films (polyvinyl alcohol, polybutylene succinate, etc.). Polysaccharide-based films have excellent mechanical properties, water vapor transmission rates, and other physical characteristics. Films can fulfill numerous demands for fruit packaging in daily life. Additionally, they can be loaded with various types of non-toxic and non-biocidal materials such as bioactive substances and metal nanomaterials. These materials enhance bacterial inhibition and reduce oxidation in fruits while maintaining fundamental packaging functionality. The article discusses the design and preparation strategies of polysaccharide-based nanocomposite films and their application in fruit preservation. The types of films, the addition of materials, and their mechanisms of action are further discussed. In addition, this research is crucial for fruit preservation efforts and for the preparation of polysaccharide-based films in both scientific research and industrial applications.

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.

A comprehensive review of intelligent controlled release antimicrobial packaging in food preservation

Intelligent responsive packaging provides informative feedback or control the release of active substances like antimicrobial agents in response to stimuli in food or the environment to ensure food safety. This paper provides an overview of two types of intelligent packaging, information-responsive and intelligent controlled-release, focusing on the recent research progress of intelligent controlled-release antimicrobial packaging with enzyme, pH, relative humidity, temperature, and light as triggering factors. It also summarizes the current status of application in different food categories, as well as the challenges and future prospects. Intelligent controlled-release technology aims to optimize the antimicrobial effect and ensure the quality of food products by synchronizing the release of active substances with food preservation needs through sensing stimuli, which is an innovative and challenging packaging technology. The paper seeks to provide a reference for the research and industrial development of responsive intelligent packaging and controlled-release packaging applications in food.

Preparation of covalent organic framework-based nanofibrous films with temperature-responsive release of thymol for active food packaging

Thymol (THY) is commonly used in active food packaging, however because of its high volatility, poor water solubility, and strong aromatic odor, the application of THY is facing challenges. Herein, covalent organic frameworks (COFs) were synthesized in room temperature by asymmetric monomer exchange method for THY encapsulation, and solution blow spinning was used to fabricate the THY@COF/polycaprolactone (PCL) nanofibrous films. The synthesized COFs had a large specific surface area, porous structure, and loading capacity of 30.35% for THY, and THY@COFs possessed good thermal stability. Characterization analysis showed that THY@COFs were successfully incorporated into the PCL films and increased the barrier property of the films. Besides, the films showed good biocompatibility and antibacterial activity. Moreover, THY@COF/PCL films exhibited temperature-responsive THY release profiles, which is important for practical preservation applications, especially for preserving food in warm environments. Overall, THY@COF/PCL films possess promising potential in active food packaging.

Nanopolyhybrids: Materials, Engineering Designs, and Advances in Thermal Management

The fundamental requirements for thermal comfort along with the unbalanced growth in the energy demand and consumption worldwide have triggered the development and innovation of advanced materials for high thermal-management capabilities. However, continuous development remains a significant challenge in designing thermally robust materials for the efficient thermal management of industrial devices and manufacturing technologies. The notable achievements thus far in nanopolyhybrid design technologies include multiresponsive energy harvesting/conversion (e.g., light, magnetic, and electric), thermoregulation (including microclimate), energy saving in construction, as well as the miniaturization, integration, and intelligentization of electronic systems. These are achieved by integrating nanomaterials and polymers with desired engineering strategies. Herein, fundamental design approaches that consider diverse nanomaterials and the properties of nanopolyhybrids are introduced, and the emerging applications of hybrid composites such as personal and electronic thermal management and advanced medical applications are highlighted. Finally, current challenges and outlook for future trends and prospects are summarized to develop nanopolyhybrid materials.