Materials based on starch are considered attractive alternatives mainly due to their eco-friendly character. Moreover, these biopolymers not only partially replace existing plastics in several applications but also provide new materials with specific final properties. Different processing methods and their influence on starch film properties are described as well as different strategies to improve their functional properties such as thermomechanical processing, plasticization, chemical modification, incorporation of fillers, and additives or blending with other polymers and compatibilizers. These properties are compared with those of more frequently used conventional plastic films, by analyzing the advantages and drawbacks of starch based packaging materials. In this chapter technological processing methods, final properties, and future challenges of starch-based materials are discussed in order to wide their applications, bringing potential solutions to insert these products in the commercial market.

It is well known that starch-based materials are hydrophilic and water-soluble. Even though, water solubility raises degradability and increases degradation speed; this moisture sensitivity limits their industrial applications. Thus, in this chapter the main disadvantages of starch-based materials are well described, especially those related to their poor mechanical behavior and high water vapor permeability. Within this context, several options to solve these drawbacks are also introduced in order to widespread their industrial and commercial applications.

This chapter describes recent advances in thermoplastic starch-based blends that employ biodegradable and synthetic polymers. Blending has become an interesting way to obtain new materials with enhanced properties at a relatively low cost. Several blends have been processed from thermoplastic starch (TPS) to improve its mechanical properties while conserving its environmentally friendly character. The blending of TPS with synthetic polymers focuses on materials development to ensure that the biodegradable component is removed by microorganisms in the waste disposal while the remnant plastic is disintegrated. However, starch can be blended with other biodegradable polymers. In some cases, the presence of compatibilizers is required to enhance the interfacial adhesion between TPS and polymers. In this chapter, a detailed description of the processing method and conditions is introduced for different blends based on starch. Moreover, the structure and final properties of these materials are described using different and complementary characterization techniques.

Starch presents countless potentialities as a feedstock for the development of biodegradable-based materials. This consideration is essentially related with starch inherent biodegradability, low cost, worldwide availability, and functionality. Physicochemical and functional properties of starch condition the potential applications of this polysaccharide in the biomaterials industry. In addition, these features derive from starch botanical origin and the modifications at which this polysaccharide was subjected. Thereby, this chapter is focused on the use of several native starches, as well as, modified derivatives, to obtain biodegradable materials using different techniques. Case studies employing traditional and nonconventional native and modified starches are included. Accordingly, the development of diverse types of materials such as films, thermosealable bags, trays, utensils, and expanded starch foams, among others are mentioned. An integral description of these materials is incorporated, including structural characterization and final properties, mainly those related with their barrier capacity, mechanical behavior, and optical features.

Starch granules are mainly found in seeds, roots, and tubers. The organization of starch components (amylose and amylopectin) as well as the presence of minor constituents (lipids, phosphate ester groups, and proteins) in the granules depends on botanical source, and they determine the functionality and end-use of starch. A comprehension of granular internal organization of starch components gives information to understand starch functionality and its behavior during processing. These polysaccharides can be isolated employing several methodologies, which mainly rely on the starch origin. In general, these methods include milling (wet or dry), gravity sedimentation, centrifugation, and filtration steps. In this chapter, the organization of starch components in the granule and the diverse isolation methods from different botanical sources are described. Besides, functional and physicochemical properties of several native starches, such as pasting and thermal properties are mentioned. Usually, native starches present inappropriate characteristics for most industrial applications and, hence, they must be modified by chemical and/or physical methods in order to broad their usage possibilities. Thus, in this section, several methodologies used to modify starches are described and the properties of the obtained derivatives are also reported.

Multilevel structure and multiphase thermal transition of starch make its processing much more complex than that of synthetic polymers. This chapter discusses the unique structure and phase transition of native starch, as well as rheological properties of starch during thermal processing. The techniques used to study these characteristics are described. However, although starch can be processed using the conventional techniques designed for synthetic polymers, these techniques should be adapted along with optimized operational conditions and formulations. Regarding this, this chapter summarizes various processing techniques at laboratory and semi-industrial scales such as solution casting, extrusion, injection and compression moldings, as well as other innovative methods such as reactive extrusion. In particular, the most important aspects of starch processing pertaining to the use of plasticizers, blending with other polymers or ingredients, and orientation are discussed. Accordingly, native starch can be processed into different forms of plastic product such as films/sheets, foams and shaped articles for food packaging and other niche applications.

During the last decades, environmental issues concerning to the reduction of the garbage amount derived from used packaging materials are becoming increasingly important. In this sense, the use of bio-based materials to design a food packaging results an interesting alternative to overcome this problem. Packaging based on biopolymers must contain and protect the food products, maintain their sensory quality and safety, and communicate information to consumers, as conventional packaging. One of the most studied biopolymer is starch, due to its wide availability, non-toxic characteristics, biodegradable character as well as low cost. Despite the aforementioned advantages, starch films have a notable moisture sensitivity and low mechanical properties, compared to conventional packaging, which restricts their applications on food packaging. Moreover, films derived from starch are very brittle. In order to improve their handling, plasticizers incorporation, blending with other materials, chemical modification or a combination of these treatments are possible alternatives. This chapter focuses on the state of art related to the development of different kind of food packaging derived from starch-based materials. In this context, a detailed description and main characteristics of starch-based packaging are included.

Structural modifications of native starches could be considered as an alternative to obtain derivatives with enhanced properties, relevant in the materials field. In this chapter, the use of several modified starches from different botanical origin for this purpose is well discussed. Thus, diverse processing methods as well as characteristics and properties of these functionalized materials, are described. Particularly, actual biodegradability/compostability and food contact compliance of these novel starch-based materials are also included in this section.

Composites development, by incorporating organic or mineral fillers to starch matrices, can be used to improve their final properties. Accordingly, composites of different starch matrices reinforced with organic fillers, as well as, with mineral particles are described in this chapter. In this sense, it was reported, among others, the use of cellulose fibers from different botanical origins and clays particles. Nowadays, both academic and industrial interest in nanoscale fillers is growing since a nanostructured composite could be developed from a polymeric matrix and layered mineral particles. Thus, in this chapter is also included the development of nanocomposites based on thermoplastic starch and talc nanoparticles from different geological origins and morphologies. Processing methods and structural and final properties of composites are described.