Emulsion-based Systems for Delivery of Food Active Compounds

Formation, Application, Health and Safety

Shahin Roohinejad, Ralf Greiner, Indrawati Oey, Jingyuan Wen, Shahin Roohinejad, Ralf Greiner, Indrawati Oey, Jingyuan Wen

• Publisher: Wiley
• Year: 2018
• ISBN:
  9781119247166
• Edition: 1
• Topic: Technik & Maschinenbau
• Subtopic: Lebensmittelwissenschaft

A comprehensive text that offers a review of the delivery of food active compounds through emulsion-based systems

Emulsion-based Systems for Delivery of Food Active Compounds is a comprehensive recourse that reviews the principles of emulsion-based systems formation, examines their characterization and explores their effective application as carriers for delivery of food active ingredients. The text also includes information on emulsion-based systems in regards to digestibility and health and safety challenges for use in food systems.

Each chapter reviews specific emulsion-based systems (Pickering, multiple, multilayered, solid lipid nanoparticles, nanostructured lipid carriers and more) and explains their application for delivery of food active compounds used in food systems. In addition, the authors – noted experts in the field – review the biological fate, bioavailability and the health and safety challenges of using emulsion-based systems as carriers for delivery of food active compounds in food systems. This important resource:

• Offers a comprehensive text that includes detailed coverage of emulsion-based systems for the delivery of food active compounds
• Presents the most recent development in emulsion-based systems that are among the most widely-used delivery systems developed to control the release of food active compounds
• Includes a guide for industrial applications for example food and drug delivery is a key concern for the food and pharmaceutical industries

Emulsion-based Systems for Delivery of Food Active Compounds is designed for food scientists as well as those working in the food, nutraceutical and pharmaceutical and beverage industries. The text offers a comprehensive review of the essential elements of emulsion-based systems for delivery of food active compounds.

1
Conventional Emulsions

Mehrdad Niakousari¹, Maral Seidi Damyeh¹, Hadi Hashemi Gahruie^1,2, Alaa El‐Din A. Bekhit³, Ralf Greiner⁴, and Shahin Roohinejad⁴

¹ Department of Food Science and Technology, School of Agriculture, Shiraz University, Shiraz, Iran

² Biomolecular Engineering Laboratory, Department of Food Science and Technology, School of Agriculture, Shiraz University, Shiraz, Iran

³ Department of Food Science, University of Otago, Dunedin, New Zealand

⁴ Department of Food Technology and Bioprocess Engineering, Max Rubner‐Institut, Federal Research Institute of Nutrition and Food, Karlsruhe, Germany

1.1 Introduction

Food active ingredients are widely used in the food industry to improve the nutritional and physicochemical properties and prolong the shelf‐life of food products. Incorporation of food active ingredients within foods has its own challenges, such as poor chemical stability, low bioavailability, and low water solubility. Thus, various studies have been conducted to develop effective systems for the delivery of these compounds (Cummings and Overduin, 2007; Maljaars, et al., 2009).

A variety of food active compounds can be incorporated into foods via specifically designed delivery systems with the aim of achieving a certain level of protection and reaching a specific targeted site, i.e. to control their release at specific locations within the gastrointestinal tract (e.g. mouth, stomach, small intestine, or colon) (Kosaraju, 2005). Delivery systems should be able to protect these compounds from physical and/or chemical degradation during processing, handling, and storage, and deliver them to the required site in the gastrointestinal tract without adverse effects on the appearance, stability, texture, or flavor of the food products (McClements, 2010; McClements et al., 2009). Conventional emulsions are considered the most important systems since they are the most widely used in the food industry (Augustin and Sanguansri, 2017).

Conventional emulsions are defined as emulsions having a particle size over 100 nm and are mostly produced using high‐energy techniques. Homogenizers are usually used to facilitate the conversion of two immiscible liquids into an emulsion with the aid of an emulsifier. High‐speed mixers, microchannel homogenizers, high‐pressure valve homogenizers, microfluidizers, colloid mills, membrane and ultrasonic homogenizers are some of the important high‐energy systems used at the industrial and research scales.

This chapter will focus on the formation, characterization, and recent advances in the application of conventional emulsions as a delivery system of valuable food ingredients. The stability of these systems under in vitro/in vivo conditions is also discussed.

1.2 Conventional Emulsions Formation and Stability

1.2.1 Formation

There are two types of naturally occurring emulsions that are found in food systems: typical low‐volume fraction emulsions such as milk and sauces, and a high‐volume fraction such as butter and margarine (Moschakis, 2013). Numerous food emulsions are prepared by combining raw materials, some of which are not found conjointly in nature. For example, a salad dressing product is manufactured by combining water, milk protein, soybean oil, apple vinegar, and seaweed polysaccharides. Each component of the formulation will influence the physical (intermolecular or interdroplet forces, phase separations) and chemical (formation of covalent bonds) properties of the product (Friberg et al., 2004).

Depending on the nature of the starting materials and method used to create an emulsion, the process may involve a single or a number of consecutive steps. In order to convert two separate oil and water phases into an emulsion, different functional ingredients should be dispersed first into the phase in which they are most soluble. For instance, lipid‐soluble compounds (e.g. oil‐soluble vitamins, antioxidants, and pigments) are mixed first in the oil phase, while water‐soluble compounds (e.g. proteins, polysaccharides, phenolic compounds, water‐soluble pigments, and vitamins) are mixed first in water phase (McClements and Li, 2010). However, sometimes it is more convenient to mix powdered functional ingredients directly into a mixture of oil and water. In order to prevent clumping during subsequent mixing and homogenization processes, the intensity and duration of the mixing process need to be optimized (Kinsella and Whitehead, 1989).

The presence of crystalline materials in the lipid phase prevents the formation of a stable emulsion. Therefore, a preheating step to melt fats prior to homogenization is required. Excessive heating, however, may initiate/promote the oxidation of polyunsaturated lipids, which in turn adversely affects the product quality (Ochomogo and Monsalve‐Gonzalez, 2009). Some parameters such as optimum conditions of ingredient mixing, solvent type, and operation temperature are important in the production of a stable functional emulsion.

As mentioned earlier, homogenization is used to convert two immiscible liquids into an emulsion with the aid of an emulsifier. Depending on the initial concentration of the two liquid phases, two different types of emulsions can be obtained in the presence of an emulsifier; at high oil and low oil concentrations, water in oil (w/o) and oil in water (o/w) emulsions will be formed, respectively (Figure 1.1). The balance between two opposing physical processes as well as the droplet disruption and coalescence will have a huge impact on the size of the droplets produced by the homogenization process (Schubert et al., 2003; Walstra, 2003).

Figure 1.1 Cream and butter as oil‐in‐water and water‐in‐oil food emulsion.

1.2.2 Stability

Emulsion stability is defined as the ability of an emulsion to resist changes to its properties over time. Stable emulsions have high resistance against changes in their properties and vice versa. Various physical and chemical processes may cause instability of an emulsion. As shown in Figure 1.2, several mechanisms such as creaming, sedimentation, flocculation, coalescence, partial coalescence, phase inversion, and Ostwald ripening can contribute to physical instability of an emulsion (Walstra, 2003). Oxidation and hydrolysis are the most common reasons for chemical instability of emulsions (McClements and Decker, 2000). A clear understanding of each mechanism, the interplay of relationships between oxidation and hydrolysis, and the processing and storage factors that influence them should be established in order to achieve more stable products.

Figure 1.2 Schematic diagram of emulsion destabilization.

Although several studies have tried to elucidate the general principles governing the stability of emulsions in order to predict their behavior under different processing conditions, the compositional and structural complexities of some emulsions do not allow accurate prediction of stability during storage (Goff and Hartel, 2003). Analytical techniques are normally used to monitor changes in emulsion properties over time. Environmental conditions (e.g. temperature and humidity of storage, mechanical agitation, and storage time) as well as composition and microstructure of an emulsion have major effects on the rate of breakdown and the mechanism by which this breakdown occurs.

1.3 Composition of Conventional Emulsions for Food Applications

The aqueous phase (W) of conventional emulsions can solubilize different amounts of water‐soluble ingredients such as acids, minerals, bases, preservatives, flavors, vitamins, surfactants, sugars, polysaccharides, and proteins. The partitioning, solubility, conformation, volatility, and chemical reactivity of some of these food components are measured by their interactions with water.

Lipids play an important part in beverage emulsions as flavor carriers or as the source of flavor themselves, such as essential oils (Tan, 2004). The choice of a suitable lipid in a formulation will have a huge impact on the nutritional, physicochemical, and sensory properties of conventional emulsions. In the formulation of a conventional emulsion, lipid acts as a solvent for hydrophobic food active ingredients such as oil‐soluble vitamins and antioxidants, preservatives, and essential oils.

The term “emulsifier” describes any surface active component that is able to interact...

Table of contents

• Cover
• Title Page
• Table of Contents
• Preface
• About the Editors
• List of Contributors
• 1 Conventional Emulsions
• 2 Pickering Emulsions
• 3 Multiple Emulsions
• 4 Multilayered Emulsions
• 5 Solid Lipid Nanoparticles
• 6 Nanostructured Lipid Carriers
• 7 Filled Hydrogel Particles
• 8 Nanoemulsions
• 9 Microemulsions
• 10 Liposomes and Niosomes
• Index
• End User License Agreement