Effect of bovine bone collagen and nano-TiO2 on the properties of hydroxypropyl methylcellulose films

Metal-Based Nanoparticles in Food Packaging and Coating Technologies: A Review

Food security has continued to be a topic of interest in our world due to the increasing demand for food. Many technologies have been adopted to enhance food supply and narrow the demand gap. Thus, the attempt to use nanotechnology to improve food security and increase supply has emerged due to the severe shortcomings of conventional technologies, which have made them insufficient to cater to the continuous demand for food products. Hence, nanoparticles have been identified to play a major role in areas involving food production, protection, and shelf-life extensions. Specifically, metal-based nanoparticles have been singled out to play an important role in manufacturing materials with outstanding properties, which can help increase the shelf-life of different food materials. The physicochemical and biological properties of metal-based nanoparticles, such as the large surface area and antimicrobial properties, have made them suitable and adequately useful, not just as a regular packaging material but as a functional material upon incorporation into biopolymer matrices. These, amongst many other reasons, have led to their wide synthesis and applications, even though their methods of preparation and risk evaluation remain a topic of concern. This review, therefore, briefly explores the available synthetic methods, physicochemical properties, roles, and biological properties of metal-based nanoparticles for food packaging. Furthermore, the associated limitations, alongside quality and safety considerations, of these materials were summarily explored. Although this area of research continues to garner attention, this review showed that metal-based nanoparticles possess great potential to be a leading material for food packaging if the problem of migration and toxicity can be effectively modulated.

Green preparation of 3D micronetwork eugenol-encapsuled porous starch for improving the performance of starch-based antibacterial film

In order to find a non-enzymatically treated alternative wall material with effective encapsulation properties, and to reduce the use of conventional non-biodegradable plastics, a novel 3D-micronetwork porous starch (3D-MPS) was created via a modified sacrificial template method to encapsulate eugenol (3D-EMPS) and used to incorporate with TiO₂-starch film, for significantly improving the performance of starch-based antibacterial film. At the template SiO₂ nanoparticles concentration of 0.1 %, the 3D-MPS exhibited anticipated alveolate structure with internal aperture of approximately 10 μm confirmed by SEM. With addition of 3D-EMPS, higher tensile strength (29.70 Mpa) and water barrier property (924 g/cm²·24 h) of the composite film was obtained. Moreover, molecular docking technique was used to model the intermolecular forces, which showed that the major forces maintaining the internal bonding of the composite film were hydrogen bonding and the interaction between eugenol and 3D-MPS skeleton in 3D-EMPS. Meanwhile, the composite film demonstrated the expected eugenol retardation and antimicrobial capacity against S. aureus, E. coli, and B. subtilis. Finally, the composite films were used for evaluating the feasibility in the actual food, which largely extended its shelf life compared to the negative control. This high-performance film revealed their potential for packaging materials application.

Soy Protein/Polyvinyl-Alcohol (PVA)-Based Packaging Films Reinforced by Nano-TiO2

This work was investigated to prepare a reinforcing composite packaging film composited of soy protein/polyvinyl alcohol (PVA) and nano-TiO2. First, different film compositions were designed by the particle size of nano-TiO2, concentration of nano-TiO2, concentration of polyvinylpyrrolidone (PVP, a dispersing agent for nano-TiO2), and pH of film casting solution. Then, the film composition that yielded the optimal physical properties was identified using orthogonal array design single-factor experiments, considering its physical properties, including tensile strength, elongation, water absorption, water vapor transmission, oxygen permeation, thermal property, and film morphology. The results displayed that the optimal film composition was (1) soy protein/PVA film with 2.5 wt% nano-TiO2, (2) 30 nm nano-TiO2 particle size, (3) 1.5 wt% PVP, and (4) pH 6.0 of film-forming solution. It yielded tensile strength of 6.77 MPa, elongation at break rate of 58.91%, and water absorption of 44.89%. Last, the films were characterized by scanning electron microscope (SEM) and differential scanning calorimetry (DSC). SEM analysis showed that compared with the film without TiO2, the film containing TiO2 has a smoother surface, and DSC determined that adding nano-TiO2 can improve the thermostability of soy protein/PVA film. Therefore, the film prepared in this paper is expected to provide a new theoretical basis for use in the packaging industry.

Tunable mechanical behavior of collagen-based films: A comparison of celluloses in different geometries

Collagen (Col) films were reinforced by celluloses in different geometries: microcrystalline cellulose (MCC), cellulosic fines (CF), cellulose nanofiber (CNF) and cellulose nanocrystals (CNC). The reinforcement mechanisms were investigated by the elastoplasticity and fracture appearance. Compared with the fracture stress of collagen film (67.5 MPa), the Col-CNF films effectively borne the stress (95.8 MPa) by intercrystalline fracture, ascribing the abundant hydrogen bonding and mechanical locking between cellulose and collagen. The toughness of Col-CF films was increased by the interfibrillar slippage of CF and pull-off of CF within the matrix, improving the strain-to-break from 8.37% to 12.13%. The films added with MCC and CNC weaken the mechanical behavior, due to the defects and lack of mechanical locking. Besides, the effects of celluloses' geometries on the thickness, density, water-tightness, thermal stability, crystallinity and FTIR of films were also investigated. These provide the evidence that the geometries of fillers diversely improve the behaviors of collagen film offering strategies for the film with adjustable mechanical properties.

Titanium dioxide nanoparticles as multifunctional surface-active materials for smart/active nanocomposite packaging films

Environmental issues such as plastic packaging and high demand for fresh and safe food has increased the interest for developing smart/active food packaging films with colloidal nanoparticles (NPs). Titanium dioxide nanoparticles (TNPs) are cost effective and stable metal oxide NPs which could be used as a functional nano-filler for biodegradable food packaging due to their excellent biocompatibility, photo catalyzing, and antimicrobial properties. This article has comprehensively reviewed the functional properties and advantages of TNPs-containing smart/active films. The advantage of adding TNPs for ameliorating food packaging materials such as their physical, mechanical, moisture/light barrier, optical, thermal resistance, microstructure and chemical properties as well as, antibacterial, and photocatalytic properties are discussed. Also, the practical and migration properties of administrating TNPs in food packaging material are investigated. The ethylene decomposition activity of TNPs containing active films, could be used for increasing the shelf life of fruits/vegetables after harvesting. TNPs are safe with negligible migration rates which could be used for fabrication of multifunctional smart/active packaging films due to their antimicrobial properties and ethylene gas scavenging activities.

An Overview of Cellulose Derivatives-Based Dressings for Wound-Healing Management

Presently, notwithstanding the progress regarding wound-healing management, the treatment of the majority of skin lesions still represents a serious challenge for biomedical and pharmaceutical industries. Thus, the attention of the researchers has turned to the development of novel materials based on cellulose derivatives. Cellulose derivatives are semi-synthetic biopolymers, which exhibit high solubility in water and represent an advantageous alternative to water-insoluble cellulose. These biopolymers possess excellent properties, such as biocompatibility, biodegradability, sustainability, non-toxicity, non-immunogenicity, thermo-gelling behavior, mechanical strength, abundance, low costs, antibacterial effect, and high hydrophilicity. They have an efficient ability to absorb and retain a large quantity of wound exudates in the interstitial sites of their networks and can maintain optimal local moisture. Cellulose derivatives also represent a proper scaffold to incorporate various bioactive agents with beneficial therapeutic effects on skin tissue restoration. Due to these suitable and versatile characteristics, cellulose derivatives are attractive and captivating materials for wound-healing applications. This review presents an extensive overview of recent research regarding promising cellulose derivatives-based materials for the development of multiple biomedical and pharmaceutical applications, such as wound dressings, drug delivery devices, and tissue engineering.

Smart Food Packaging Designed by Nanotechnological and Drug Delivery Approaches

This paper offers a general view of the solutions that are able to confer bioactivity to the packaging materials, especially antimicrobial and antioxidant activity. These properties can be induced by the nature of the polymers blend or due to the addition of ternary components from natural agents (essential oils or other extracts) to synthetic organic and inorganic agents, including nanoparticles with a broad antimicrobial activity such as metals (e.g., Ag, Au, Cu) or metal oxide (e.g., TiO2, ZnO) nanoparticles, and even bacterial cells such as probiotics. Many times, these components are synergistically used, each of them assuring a specific role or potentiating the role of the other components. The antimicrobial activity can be induced due to the applied coatings or due to the whole bulk material. Along with an increasing food stability which means a longer shelf-life some smart packaging can be exploited in order to highlight the freshness of the food. These act as a sensor (usually pH sensitive but also other mechanisms can be exploited such as aggregation/agglomeration of AuNPs leading to color change or even aldehyde-specific reactions such as the Cannizzaro reaction), and thus, consumers can be confident about the freshness of the food, especially perishable food such as seafood or fish.