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About this book

Starch is one of the most important natural and biodegradable polymers on Earth. It is used by many plants as an energy reserve, and due to its biocompatibility and relatively easy structural modification, it is widely used in the cosmetic, food, pharmaceutical and materials industries. In recent years, interest in starch has increased due to the development of starch-based nanomaterials. Nanomaterials are small particles—diameters ranging from 10 nm to 500 nm—that can be highly crystalline (nanocrystals) or completely amorphous (nanoparticles). Owing to their versatility, starch-based nanomaterials can be used as carriers of bioactive molecules to improve medical treatments or nutrient absorption. They can also be used as reinforcement in composite materials, improving their mechanical and barrier properties, and new potential applications are continuously reported in the literature. This brief provides a quick guide to the exciting world of starch-based nanomaterials, including their chemical and physical characteristics as well as their synthesis methods and most common applications.

Table of Contents

Frontmatter

Chapter 1. Introduction

Abstract
The study of materials on the nanoscale, around 1–500 nm, has been one of the greatest scientific revolutions of the last decades, as the properties of these materials drastically changes from their bulk counterpart. Furthermore, their physicochemical, optical and electronic properties heavily depend on their size, morphology and chemical composition, and all those parameters can be easily changed through physical and chemical methods. (Jeevanandam et al. 2018). Is because of this that nanotechnology and nanoscience have emerged in the last decades of the twentieth century and the firsts of the twenty first century, impregnating almost all aspects of science and technology. (Bazak et al. 2015; Bouwmeester et al. 2009; De et al. 2014; Jeevanandam et al. 2018; Labouta and Schneider 2013).
Cristian Camilo Villa Zabala

Chapter 2. An Overview on Starch Structure and Chemical Nature

Abstract
Starch is considered the second most common biomass on earth, as it is produced by green plants as an energy reserve. It is found as granules of different morphologies (depending of the botanical source) in plant tissues, mainly seed, roots, tubers, leaves and fruits. (Odeku 2013; Pérez and Bertoft 2010; Zia ud et al. 2017). On a cellular level, starch is synthesized in two types of plastids, chloroplasts and amyloplasts, through three main pathways: The Calvin cycle, sucrose synthesis and storage starch biosynthesis. (Hsieh et al. 2019; Tappiban et al. 2019). Chemically, starch can be defined as a polysaccharide composed of α-D-glucopyranosyl units that can be linked in either α-D-(1–4) and/or α-D-(1–6) linkages. These molecular linkages form to types of molecules: the linear amylose formed by approximately 1000 glucose units linked in α-D-(1–4) manner and the branched amylopectin, formed by approximately 4000 glucose units, branched through α-D-(1–6) linkages, as shown in Fig. 2.1. The union of both amylose and amylopectin forms a semi-crystalline structure arranged as small granules with diameters between 1–100 μm. Most of the native starches have amylose percentages that range between 70 and 80% and amylopectin ranging from 20 to 30%. Furthermore, some types of starch can have a very high amylose content, such as starch extracted from amylomaize with a 70% of amylose and some can have very low amylose content such as waxy maize starch with a 1% amylose content.
Cristian Camilo Villa Zabala

Chapter 3. Starch Nanoparticles and Nanocrystals

Abstract
Starch-based nanosystems are commonly classified in two main groups: starch nanocrystals (SNc) and starch nanoparticles (SNp). SNc are obtained by hydrolysis of the amorphous phase of the starch granule, removing mostly amylose until nanosized particles are achieved. On the other hand, SNp are almost completely amorphous particles that are commonly obtained by the controlled nanoprecipitation of gelatinized starch. It’s been reported that SNp tend to have bigger particle sizes than SNc and that in both cases their size and morphology can be controlled through the synthesis method. On the other hand, the botanical source doesn’t play an important role in either SNc and SNp physical characteristics.(LeCorre et al. 2011; LeCorre et al. 2012a)
Cristian Camilo Villa Zabala

Chapter 4. Starch-Based Nanomateriales as Carriers in Drug and Nutrient Delivery

Abstract
Nanoencapsulation is an expanding field among nanoscience, as it has a lot of potential applications, especially in the pharmaceutical and food industries. It involves the introduction of small particles in nano sized capsules of a wall material. (Ezhilarasi et al. 2013) There is a variety of bioactive molecules that have generated great interest in both pharmaceutical and food industries due to their antimicrobial, antioxidant, anti-inflammatory or anticancer activities, among others. Nevertheless, their application has been limited due to several factors, such as sensibility to O2, CO2 and light; low-water solubility and low bioavailability. (Akhavan et al. 2018; Pathakoti et al. 2017; Rostamabadi et al. 2019). Hence, nanoencapsulation has probe to be a powerful technique in the protection and controlled release of several bioactive molecules, proteins, enzymes and peptides.
Cristian Camilo Villa Zabala

Chapter 5. Starch-Based Nanomateriales as Fillers in Composite Polymeric Films

Abstract
One of the most common applications of starch based nanosystems is as fillers in composite polymeric films, as they have shown the capability to improve mechanical, barrier and electrical properties of the films. (Le Corre and Angellier-Coussy 2014). Starch based nanosystems, specially SNc, have been of use in order to improve properties of biodegradables films made from biodegradables polymers, however some examples can be found of their use in non-biodegradables composite polymers.
Cristian Camilo Villa Zabala
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