A facile method to prepare cellulose fiber-based food packaging papers with improved mechanical strength, enhanced barrier, and antibacterial properties

Chitosan/acrylic rosin-based superhydrophobic coatings inspired by Pickering emulsion template and lotus leaf surface structure for paper-based food packaging

The superhydrophobic coated papers have attracted much attention as the promising alternatives for disposable plastic packaging materials in food packaging fields. Despite recent visible progress in constructing superhydrophobic coated papers, it is still a challenge to realize superhydrophobicity, high oil-resistant behavior, biodegradability and recyclability at the same time in a coated paper. Herein, we have effectively constructed the superhydrophobic coated (PE&SP-CP) paper with the imitated lotus leaf surface structures by firstly dip-coating cellulose nanocrystals stabilized Pickering emulsion containing chitosan in water phase and acrylic rosin (AAR) in oil phase, and then spraying ethanol suspension of hydrophobic nano-silica (hSiO2) and polydimethylsiloxane (PDMS). In this aspect, the micro-nano hierarchical surface of chitosan-based coating film consists of AAR microcapsules and hSiO2 nanoparticles, as well as covered a hydrophobic PDMS polymer layer. And the prepared PE&SP-CP paper with surface superhydrophobicity demonstrates the highly water barrier performance with the water contact angle of 155.8° and water vapor permeability rate of 1.42 × 10-10 gm-1s-1Pa-1, the favorable oil repellency with the kit rating of 9/12, the clearly improved tensile strengths of 21.67 MPa. Interestingly, the PE&SP-CP paper also shows superior antifouling performance, self-cleaning ability, biodegradability of soil burial and recyclability. This work provides a universal approach for the effective construction of oil-resistant, self-cleaning, antifouling, recyclable, biodegradable superhydrophobic coated paper with the imitated lotus leaf surface structure, which has great potential application in the food packaging industry.

Advances in polysaccharide-based antibacterial materials

Microbial contamination is a major threat to the public health and a primary cause of food spoilage, leading to significant economic losses worldwide. Various materials have been used to combat microbes, including inorganic materials, metals and polymers. Among these, natural polymers have attracted much attention in both academic and industrial research due to their abundance, renewability, biocompatibility, biodegradability and ease of processing. Polysaccharides, such as cellulose and chitosan (chitin), are a crucial category of natural polymers. However, most polysaccharides lack inherent antibacterial activity, limiting their applications in fields like antibacterial packaging and wound dressing etc. Therefore, it is crucial to increase their antibacterial property to expand their application as green antibacterial materials. Various methods, including blending, grafting and in-situ synthesis, have been used to fabricate polysaccharide-based antibacterial materials. This review highlights the major advancements and potential of novel polysaccharide-based antibacterial materials, primarily used in antibacterial food packaging or wound dressings. Moreover, the future prospects and challenges of polysaccharide-based antibacterial materials and the incorporated antimicrobial compounds are also discussed.

From nature to nanotech: Harnessing the power of electrospun polysaccharide-based nanofibers as sustainable packaging

Today, the applications of natural polysaccharide-based nanofibers are growing in drug delivery and food industries. They also showed their capability as packaging due to biodegradability, mechanical strength, barrier properties, thermal stability, antioxidant, and antimicrobial features. Natural polysaccharides come from different sources, such as plants, microbes, and animals. Natural polysaccharide-based nanofibers can be considered sustainable packaging in contrast to plastic packaging due to their safety and biodegradability. Smart packaging is a new trend in packaging materials, and natural polysaccharides can be applied as smart packaging. They can work as an indicator that confirms food health in food packaging. Electrospinning is one of the most used methods for the fabrication of nanofibers, and it can also be used for the fabrication of natural polysaccharide nanofibers. This method can be scaled up and used to fabricate nanofibers on a large scale. This paper will review recent studies on natural polysaccharide-based nanofiber as packaging materials and their benefits. We also discuss the challenges and limitations of their scale-up and electrospinning process. Furthermore, we will discuss the future perspective of natural polysaccharide-based nanofiber as a new sustainable packaging.

The Effect of Fibrillation, Semi-Dry Pressing, and Surface Treatment on the Barrier Properties of Water Molecules and Oxygen on Food Packaging Paper

The characteristics of fiber morphology and paper structure are critical to the barrier properties of food packaging paper. Herein, this study aimed to use pulp fibrillation, paper semi-dry pressing and carboxymethyl starch (CMS) coating to flatten the fibers, which were formed on the paper surface with good barrier properties due to the tight bond between fibers. The results showed that the permeability of paper was reduced by 87.56%, from 81.44 μm/Pa·s to 10.13 μm/Pa·s after the pulp fibrillation treatment (60 °SR). Moreover, semi-dry pressing treatment contributed to decreasing the water vapor transmission coefficient (WVP) by 50.98% to 2.74 × 10-10 g/m·s·Pa, and the oxygen permeation coefficient (OP) decreased by 98.04% to 1.93 × 10-14 cm3·cm/cm2·s·Pa. After coating the paper surface with titanium dioxide (TiO2) and CMS, the WVP of the paper was further reduced to 1.55 × 10-10 g/m·s·Pa, and OP was reduced to 0.19 × 10-14 cm3·cm/cm2·s·Pa. These values were 72.27% and 99.8% lower than those of the original paper, respectively. Therefore, through pulp fibrillation, semi-dry pressing of paper, TiO2 filling, and surface coating with CMS, there is no need to use synthetic polymer surface film-forming agents to achieve the high barrier properties that are required for low water and oxygen molecules permeation in food packaging paper.

Paper-based material with hydrophobic and antimicrobial properties: Advanced packaging materials for food applications

The environmental challenges posed by plastic pollution have prompted the exploration of eco-friendly alternatives to disposable plastic packaging and utensils. Paper-based materials, derived from renewable resources such as wood pulp, non-wood pulp (bamboo pulp, straw pulp, reed pulp, etc.), and recycled paper fibers, are distinguished by their recyclability and biodegradability, making them promising substitutes in the field of plastic food packaging. Despite their merits, challenges like porosity, hydrophilicity, limited barrier properties, and a lack of functionality have restricted their packaging potential. To address these constraints, researchers have introduced antimicrobial agents, hydrophobic substances, and other functional components to improve both physical and functional properties. This enhancement has resulted in notable improvements in food preservation outcomes in real-world scenarios. This paper offers a comprehensive review of recent progress in hydrophobic antimicrobial paper-based materials. In addition to outlining the characteristics and functions of commonly used antimicrobial substances in food packaging, it consolidates the current research landscape and preparation techniques for hydrophobic paper. Furthermore, the paper explores the practical applications of hydrophobic antimicrobial paper-based materials in agricultural produce, meat, and seafood, as well as ready-to-eat food packaging. Finally, challenges in production, application, and recycling processes are outlined to ensure safety and efficacy, and prospects for the future development of antimicrobial hydrophobic paper-based materials are discussed. Overall, the emergence of hydrophobic antimicrobial paper-based materials stands out as a robust alternative to plastic food packaging, offering a compelling solution with superior food preservation capabilities. In the future, paper-based materials with antimicrobial and hydrophobic functionalities are expected to further enhance food safety as promising packaging materials.

Chitin and Chitosan as Polymers of the Future-Obtaining, Modification, Life Cycle Assessment and Main Directions of Application

Natural polymers are very widespread in the world, which is why it is so important to know about the possibilities of their use. Chitin is the second most abundant reproducible natural polymer in nature; however, it is insoluble in water and basic solvents. Chitin is an unused waste of the food industry, for which there are possibilities of secondary management. The research led to obtaining a soluble, environmentally friendly form of chitin, which has found potential applications in the many fields, e.g., medicine, cosmetics, food and textile industries, agriculture, etc. The deacetylated form of chitin, which is chitosan, has a number of beneficial properties and wide possibilities of modification. Modification possibilities mean that we can obtain chitosan with the desired functional properties, facilitating, for example, the processing of this polymer and expanding the possibilities of its application, also as biomimetic materials. The review contains a rich description of the possibilities of modifying chitin and chitosan and the main directions of their application, and life cycle assessment (LCA)-from the source of the polymer through production materials to various applications with the reduction of waste.

Emerging Food Packaging Applications of Cellulose Nanocomposites: A Review

Cellulose is the most abundant biopolymer on Earth, which is synthesized by plants, bacteria, and animals, with source-dependent properties. Cellulose containing β-1,4-linked D-glucoses further assembles into hierarchical structures in microfibrils, which can be processed to nanocellulose with length or width in the nanoscale after a variety of pretreatments including enzymatic hydrolysis, TEMPO-oxidation, and carboxymethylation. Nanocellulose can be mainly categorized into cellulose nanocrystal (CNC) produced by acid hydrolysis, cellulose nanofibrils (CNF) prepared by refining, homogenization, microfluidization, sonification, ball milling, and the aqueous counter collision (ACC) method, and bacterial cellulose (BC) biosynthesized by the Acetobacter species. Due to nontoxicity, good biodegradability and biocompatibility, high aspect ratio, low thermal expansion coefficient, excellent mechanical strength, and unique optical properties, nanocellulose is utilized to develop various cellulose nanocomposites through solution casting, Layer-by-Layer (LBL) assembly, extrusion, coating, gel-forming, spray drying, electrostatic spinning, adsorption, nanoemulsion, and other techniques, and has been widely used as food packaging material with excellent barrier and mechanical properties, antibacterial activity, and stimuli-responsive performance to improve the food quality and shelf life. Under the driving force of the increasing green food packaging market, nanocellulose production has gradually developed from lab-scale to pilot- or even industrial-scale, mainly in Europe, Africa, and Asia, though developing cost-effective preparation techniques and precisely tuning the physicochemical properties are key to the commercialization. We expect this review to summarise the recent literature in the nanocellulose-based food packaging field and provide the readers with the state-of-the-art of this research area.