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Overview of Different Materials Used in Food Production

Nahed A. Abd El-Ghany* and Mahmoud H. Abu Elella

Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt
* Corresponding author

Highlights

• Materials science and engineering can be applied to different aspects of food science, ranging from encapsulation of food ingredients to food packaging.
• Materials engineering, depending on biopolymers, has gained extensive interest because polymers have shown outstanding properties, such as nontoxicity, ease of availability, biocompatibility, biodegradability, and low cost.
• Materials engineering can enhance food product quality, which is all about sensory features, such as taste, flavor, palatability, and semblance.
• Advances in materials science and engineering are expected to bring new opportunities to the food industry.

1.1 Introduction

Rapid growth of materials engineering science has provided a lot of functionalized materials for food product development application in the recent years. Three advanced types of functional materials that have been widely applied in food industry are nanostructured and microstructured materials, and three-dimensional hydrogels [1]. In general, materials engineering science normally represents a solid state of matter and is an integrated field comprising chemistry, physical attributes, and processing. Additionally, it involves the maintenance of the materials' properties, for example, chemical (structure and composition), physical (thermal and optical), dimensional (shape and size), and mechanical (toughness and strength). On the other hand, food product development has been gaining more interest among many industrial and academic researchers around the world to improve the quality of food products. Notably, the major components of food are carbohydrates, and proteins that are called biopolymers [2]. In general, nowadays, polymeric materials are considered as an important class of materials in a wide range of applications, thanks to their physicochemical properties [3]. They are macromolecules composed of repeating units that are known as monomers joined by covalent bonds. According to their origin, they are classified as either natural (if produced from natural sources, such as plants, animals, and microorganisms) or synthetic [4]. Recently, biopolymers have gained more attention from global researchers in food development applications since they have fabulous properties, such as biodegradability, biocompatibility, low cost, nontoxicity, and ease of availability [4a, 5]. They include naturally extracted polymers from animal and plant origins, for example, polysaccharides and proteins. Their repeated units include sugar or protein chains [6].

Polysaccharides are an example of natural biopolymers that are composed of carbohydrate chains with a large polymeric oligosaccharide formed through glycosidic linkages between multiple monosaccharides as repeating units [7]. Polysaccharides are the most abundant natural organic compounds. Additionally, they can be extracted from natural renewable resources, including plants (e.g. cellulose), animals (e.g. chitosan and alginate), and microorganisms (e.g. xanthan gum) [5a, 7a, 8]. Also, they are classified into two categories, for instance, homopolysaccharides and heteropolysaccharides. Homopolysaccharides are composed of the same monosaccharide-repeating unit as cellulose, whereas, heteropolysaccharides are composed of various repeating units including alginate [9]. Furthermore, polysaccharides have been used in various applications owing to their sustainable properties, such as ease of availability at less cost, ease of modifications and manufacturing, biocompatibility, biodegradability, nontoxicity, and bioactivity [5a, 7a, 10]. Conversely, proteins have polyamide chains, and they are one of the main constituents of the human body because they play both dynamic and diverse roles, such as catalyzing reactions, building cellular structures, and controlling cell fates. They have fabulous physicochemical properties, including isoelectric point (pI), chemical compositions, denaturation thermal temperature (Tm), and solubility [11].

Nanotechnology has revolutionized several scientific and industrial fields, including the food business. Food processing, food packaging, functional food development, food safety, detection of foodborne pathogens, and shelf-life extension of food and/or food products have emerged because of the growing need for nanoparticles in various fields of food science and food microbiology. On the other hand, hydrogels in the food science sector are efficient materials in the field of food quality improvement, nutrient-modification, sensory perception optimization, targeted nutrient delivery and protection, calorie control, risk monitoring for food safety, and food packaging. Although applications of hydrogels in the food industry are still limited, there are large areas to promote their use in food science. As a result, it is expected that the hydrogel structure's reasonable design will lead to more useful applications in order to keep up with the development of new foods [12]. In this chapter, we focus on shaping up the biopolymer-based nanostructured, microstructured, and hydrogel materials as shown in Figure 1.1, for encapsulation of different vital food ingredients in the food packaging field and explore their effect on food safety and quality that are essential for food development.

Figure 1.1 Different advanced material engineering formulations: (a) nanoparticles [13] / from ELSEVIER, (b) microparticles [14] / from ELSEVIER, and (c) hydrogel, formulations for food industry [15] / with permission of Elsevier.

1.2 Advanced Materials Engineering for Food Product Development

1.2.1 Microstructured and Nanostructured Materials

Microstructured materials refer to the formulation of particle-sized compounds in the range of 1-1000 µm in diameter for different purposes, such as controlling and sustained bioactive compounds delivery, in addition to protecting the bioactive compounds from harsh environmental conditions. They have outstanding properties including a micro-size diameter and have the ability to encapsulate macromolecules with a high molecular weight [16]. For example, microcapsules based on the biopolymer mixture of chitosan and alginate have been reported in the literature [17], for encapsulating biologically active compounds, such as Garcinia kola (GK) and Hunteria umbellata (HU) seeds. The results showed that the extracted seeds have selective release patterns based on the pH of the medium. Also, a slower release of GK and HU from microcapsules was observed in an acidic medium (pH 1.2), but rose in a slightly neutral medium (pH 6.8). Nanostructured materials can be described as chemically and morphologically deposited matters in the range of 1-300 nm in diameter. All sorted materials used form the nanoscale and are classified from atoms to polymers. Moreover, nanostructured biopolymers are functional materials and controlling their architecture leads to achieved materials with amazing properties. For example, due to their nanometric dimension, which is less than the wavelength of light, they can display optical properties such as anti-reflectivity and structural colors [18].

1.2.2 Preparation Methods

1.2.2.1 Spray-Drying Technique

Spray-drying technique has been one of most widely used methods to design microparticle materials in the past decades due to its fabulous features, such as simplicity, speed, low cost, ease of scaling up, and flexibility [19]. It is also used to prepare microcapsule formulations for drug delivery applications in which the core material is dispersed in the solution of the shell material, such as water, after which, it is fed into the drying chamber while atomized under hot air coming from a pressure nozzle. Subsequently, the solvent is evaporated under the hot air stream, leaving a microparticle of solid. Additionally, this approach is a simple and flexible one to yield consistently distributed particle size in the range of 10-40 µm in diameter (Figure 1.2a) [20]. The spray-drying method allows a large-scale yield and high encapsulation efficiency in pharmaceutical applications, as well as excellent stability of the prepared product and ease of handling and maintenance of their properties [21].

Figure 1.2 Schematic illustration of the (a) spray-drying technique Adapted from [20b], (b) electrospinning technique [22b] / with permission of Elsevier, and (c) coacervation technique [25b] / with permission of ScienceAsia.

1.2.2.2 Electrospinning Technique

Electrospinning technique is an effective method of fabricating micro- and nanoscale fibrous materials based on different biopolymers owing to their sustainable properties, including effectivity, low cost, and versatile technique. Also, it has been widely applied in recent years since it has many valuable advantages, such as high surface-to-volume ratio, high porosity, and ultrafine structures of the prepared fibers (Figure 1.2b). Figure 1.2b shows that it is non-mechanical technique and includes a high-voltage electrostatic field to charge droplets on a polymer solution surface, and then, induce the ejection of a liquid jet via a spinneret...