Advances in Cellulose-Based Packaging Films for Food Products

*Eda Ceren Kaya and Umut Yucel*

## **Abstract**

Cellulose and its derivatives can be used to manufacture packaging film materials with versatile properties as alternatives to petroleum-based films. This chapter covers the recent trends and advancements in cellulose-based films for food materials. The chapter starts with the introduction of traditional and novel cellulose structures relevant to film-making properties including cellulose fibers, filaments, nano-fibrils, crystalline cellulose, and other traditional cellulose derivatives. The relevant crosslinking methods, such as esterification, etherification, oxidation, and carboxylation will be described in the production of materials such as methylcellulose, cellulose acetate, rayon fabric, carboxymethyl cellulose, cellulose ether, etc. The chapter will relate the properties of the films (e.g., crystallinity, mechanical, optical, barrier, and solubility properties) to the chemical characteristics of the cellulose materials. The chapter will also cover the interactions of cellulose with polymeric composites such as protein, polysaccharides, and other nanoparticles ingredients with a focus on emerging technologies.

**Keywords:** packaging films, cellulose structures, cellulose derivatives, physical modifications, chemical modifications, cellulose crosslinking, cellulose interactions

### **1. Introduction**

The packaging film materials are significant contributors to safety, quality, and shelf life of food materials. They are as primary, secondary and tertiary depending on the level of contact with the product. Primary packaging films that are the focus of this chapter directly contact with products. Packaging films are made of a polymer matrix to create cohesive structure providing strength, often with a plasticizer to reduce rigidity and brittleness. They provide protection against physical and biological damage to food, and extent shelf life by limiting the diffusion of moisture, gases, volatile compounds.

Traditional packaging films are manufactured from petroleum-based polymers with tunable properties, but well-known environmental drawbacks. For example, the concentration of microplastics fragmented from synthetic films has been increasing to critical levels and is predicted to further increase in the next decades. The microplastic contamination in aquatic environment and soils considered as dominant environmental plastic pollutants to result in serious health concern for humans and animals [1]. The adoption of biodegradable films, which are known as materials that

can naturally decompose into water, carbon dioxide, methane, or biomass in three to six months, can serve as a viable solution to this problem [2]. These materials can be obtained from biomass, synthesized from bio-derived monomers or produced from microorganisms [3]. Moreover, these materials can be produced from renewable resources (i.e., cellulosic materials and fibers recovered from process waste-streams) supporting sustainable agriculture practices [4]. There is, therefore, a large need for designing biodegradable, safe, and high-performance packaging materials using biopolymer sources, such as cellulose.

Biopolymers are natural macromolecules obtained from living organisms. They can be used to produce packaging films as alternatives to petroleum-based materials. The literature has plethora of examples for such films produced from polysaccharides, proteins, lipids, and their combinations [5]. Some of the biggest challenges for the adoption of biopolymers films are related to their limited film forming abilities, and lower mechanical and gas barrier properties as compared to traditional synthetic materials. The high production cost is another limitation related to the extraction, purification, conversion, and recovery steps involved.

Cellulose is the most abundant natural biopolymer found in cell walls of all plants as well as algae and fungi. It can serve as an ideal material for film manufacturing related to its versatility, chemical stability, non-toxicity, and affordability. The versatility of cellulose is also related to its various derivatives with distinct chemical structures and physicochemical properties used in a wide array of industrial segments as covered in this chapter. For example, cellulose acetate is one of the well-known cellulose derivatives and its commonly used to produce strong and resistant films in addition to distinct applications as frame materials in personal care items and other rigid tools (glasses, combs, screwdriver handles, etc.), imaging and photography films, filters, reservoirs for liquids, synthetic fiber etc. Therefore, it is safe to claim that cellulose and its derivatives are popular in packing applications. This chapter starts with the structures and sources of cellulose relevant to film-forming characteristics; then, continues with chemical and physical approaches to tailor cellulose derivatives. The chapter also highlights various polymeric interactions within cellulose fibrillar network. The chapter adds the use of cellulose in various food film applications with advances in manufacturing cellulose-based packaging films and emerging technologies. To illustrate prior knowledge, four recent review papers were included throughout the chapter [3, 6–8].
