**Outline of the book**

This book is intended to provide an overview and review of the latest developments in microencapsulation processes and technologies for various fields of applications. The general theme and purpose are to provide the reader with a current and general overview of the existing microencapsulation systems and to emphasize various methods of preparation, characterization, evaluation, and potential applications in various fields such as medicine, food, agricultural, and composites. It targets readers, including researchers in materials science processing and/or formulation and

**VII**

microencapsulation science, engineers in the area of microcapsule development,

The book has been contributed to by a panel of international researchers and experts in the field of microencapsulation and covers various aspects of the research and development of the processes, technologies, and applications. It is composed of eight chapters, which can be divided into three main parts. The preface provides background information on microencapsulation technology, including a brief overview of this theme, and the book's structure. Thus, the chapters are arranged logically according to the materials used, the methods of preparation, and applica-

The first part involves the classification of the shell and core materials used in the main processes. Chapter 1 by S. Vijeth, G.B. Heggannavar, and M.Y. Kariduraganavar is concerned with biodegradable and responsive polymers as wall materials for developing stable and safe micro/nanocapsules, and also covers the development and progress made in the selection of suitable polymeric shells for drug-delivery systems. Chapter 2 by E. Onsaard and W. Onsaard deals with the use of vegetable power as a core component and focuses on emulsion preparation using multilayer emulsions

followed by the spray-drying technique to obtain a vegetable oil powder.

spray-drying method, and then focus on the encapsulation of aloe vera.

In the third part of the book, examples of applications are presented. S.N. Gan and N. Shahabudin discuss the methods of preparation of microcapsules for self-healing materials. In his comprehensive and exhaustive chapter, P.H.R. do Amaral underlines the potential uses of microcapsules in the food industry and emphasizes recent progress made in the last decade in understanding production methods. In the last chapter, C.F. Uzoh and O.D. Onukwuli propose the application of capsules in the agricultural field to control the release of fertilizer as a function of coating thickness.

This book will provide scientists, researchers, and students in the field of microencapsulation formulation, processes, technologies, material science, and bioengineering, and professionals in the pharmaceutical, biotechnology, food, cosmetics, textiles, and agricultural industries with an essential compendium of concepts and practical cases for their daily activities. I want to thank all the contributors of this book. I also wish to express my heartfelt gratitude to the team at IntechOpen for their help with this project.

ENSAIT, GEMTEX – Laboratoire de Génie et Matériaux Textiles,

**Fabien Salaün** Professor

Lille, France

The second part of the book, which mainly focuses on nanoemulsions and the spray-drying method, starts with a chapter by M.B. Jemaa, H. Falleh, and R. Ksouri on the concept of a nanoemulsion-based delivery system to immobilize active compounds such as essential oils. The following chapter by T.Y. Hendrawati and A.M. Sari presents a detailed explanation of the preparation and characterization of herbal compounds-loaded microcapsules. The authors clearly define the guidelines for choosing the appropriate working conditions to encapsulate turmeric by the

and students in colleges and universities.

tions of microcapsules in certain fields.

microencapsulation science, engineers in the area of microcapsule development, and students in colleges and universities.

The book has been contributed to by a panel of international researchers and experts in the field of microencapsulation and covers various aspects of the research and development of the processes, technologies, and applications. It is composed of eight chapters, which can be divided into three main parts. The preface provides background information on microencapsulation technology, including a brief overview of this theme, and the book's structure. Thus, the chapters are arranged logically according to the materials used, the methods of preparation, and applications of microcapsules in certain fields.

The first part involves the classification of the shell and core materials used in the main processes. Chapter 1 by S. Vijeth, G.B. Heggannavar, and M.Y. Kariduraganavar is concerned with biodegradable and responsive polymers as wall materials for developing stable and safe micro/nanocapsules, and also covers the development and progress made in the selection of suitable polymeric shells for drug-delivery systems. Chapter 2 by E. Onsaard and W. Onsaard deals with the use of vegetable power as a core component and focuses on emulsion preparation using multilayer emulsions followed by the spray-drying technique to obtain a vegetable oil powder.

The second part of the book, which mainly focuses on nanoemulsions and the spray-drying method, starts with a chapter by M.B. Jemaa, H. Falleh, and R. Ksouri on the concept of a nanoemulsion-based delivery system to immobilize active compounds such as essential oils. The following chapter by T.Y. Hendrawati and A.M. Sari presents a detailed explanation of the preparation and characterization of herbal compounds-loaded microcapsules. The authors clearly define the guidelines for choosing the appropriate working conditions to encapsulate turmeric by the spray-drying method, and then focus on the encapsulation of aloe vera.

In the third part of the book, examples of applications are presented. S.N. Gan and N. Shahabudin discuss the methods of preparation of microcapsules for self-healing materials. In his comprehensive and exhaustive chapter, P.H.R. do Amaral underlines the potential uses of microcapsules in the food industry and emphasizes recent progress made in the last decade in understanding production methods. In the last chapter, C.F. Uzoh and O.D. Onukwuli propose the application of capsules in the agricultural field to control the release of fertilizer as a function of coating thickness.

This book will provide scientists, researchers, and students in the field of microencapsulation formulation, processes, technologies, material science, and bioengineering, and professionals in the pharmaceutical, biotechnology, food, cosmetics, textiles, and agricultural industries with an essential compendium of concepts and practical cases for their daily activities. I want to thank all the contributors of this book. I also wish to express my heartfelt gratitude to the team at IntechOpen for their help with this project.

> **Fabien Salaün** Professor ENSAIT, GEMTEX – Laboratoire de Génie et Matériaux Textiles, Lille, France

**VI**

effectiveness of a binder in fixing microcapsules on a surface depends on the compatibility of the different interfaces between the elements involved in the process, and is closely related to the individual nature and chemical structure of

More than 200 microencapsulation methods are described in the scientific literature and patents, and most of them include three necessary steps, namely containment of the central component, formation of microparticles, and hardening of the envelope. These methods are generally divided or classified into three main groups, which are based on the mechanisms governing membrane formation, namely mechanical, chemical, and physicochemical processes. The choice of one method over another is often dictated by the cost of treatment, the use or not of organic solvents, and the consideration of health and environmental aspects. The interactions between polymers and solvents in the microencapsulation process probably have the most critical effect on the morphology and properties of the particles obtained. Thus, each encapsulation step is affected by the solvency of the oil phase, and therefore to form a separate membrane or shell, the solvent used must promote the precipitation of the polymer in the early reaction stage, and also allow the continuous diffusion of monomers through the existing membrane to allow its growth.

The most popular methods include interfacial, in-situ, and suspension polymerization methods for chemical processes, simple or complex phase coacervation for physicochemical processes, and spray drying for mechanical processes. Whatever the process selected, it includes two main steps, e.g., the emulsification step, which determines the size and size distribution of the microcapsules, and the formation of the capsules. The first step is affected immediately by physical parameters such as apparatus configuration, stirring rate, and volume ratio of the two phases, and by physicochemical properties such as interfacial tension, viscosities, densities, and chemical compositions of the two phases used. The formation of microcapsules is also related to the use of surfactants, which influences not only the mean diameter but also the stability of the dispersion. The surfactants or the colloid have two leading roles, i.e., to reduce the interfacial tension between oil and aqueous phases to allow the formation of smaller microcapsules, and to limit or prevent coalescence by its adsorption on the oil/water interface by forming a layer around the dispersed droplets. Shell formation is mainly governed by kinetic factors, i.e., the ability of the monomers, pre-polymer, or polymer to react or to cross-link, and thermodynamic factors, i.e., the minimum total free energy exchange in the system. Furthermore, the choice of the polymer system for shell synthesis needs to be considered regard-

This book is intended to provide an overview and review of the latest developments in microencapsulation processes and technologies for various fields of applications. The general theme and purpose are to provide the reader with a current and general overview of the existing microencapsulation systems and to emphasize various methods of preparation, characterization, evaluation, and potential applications in various fields such as medicine, food, agricultural, and composites. It targets readers, including researchers in materials science processing and/or formulation and

each component.

**Microencapsulation technologies**

ing the application and availability of the material.

**Outline of the book**

**1**

Section 1

Core and Shell Materials

Section 1
