Preface

Food texture is a key sensory feature not only well appreciated by consumers but also used by consumers as a quality indicator of a food product. The study of food texture has become a very active scientific area of the food science and technology and has received growing attention from scientists of food science and related disciplines. In the past few decades, some significant progresses have been made in the fundamental understanding of the textural properties and practical applications of such knowledge in the development of healthy and tasty food products. The major developments in food texture study can be briefly summarized in three areas. The first achievement is a much better understanding of the underlying scientific principles of food texture and its sensation and perception. This is shown by the establishment of the physical, mechanical, and (micro)structural nature of food textural properties and the associated physiological and psychological factors that influence texture sensation and perception. Such developments provide a solid foundation for food texture study as a scientific discipline. Second, objective assessment of food textural properties has always been a research focus for its important implications to both fundamental understanding and industrial applications. A wide range of instrumental devices and experimental techniques have been developed, and many of them are now commercially available. These include various rheometers for the precise characterization of texture-related physical and mechanical properties, various empirical devices for fast characterization of some specific textural properties, and various instruments that mimic eating and oral processing and offer easy quantification of textural properties and prediction of consumers’ perceptions. The third major development is the emergence of food texture modification in the past few decades for the purposes of either improved textural properties of a food product or altered texture of a food to suit the needs of consumers who have difficulty consuming normal food. This area has attracted much attention currently from both academic and industrial researchers due its close relevance to the fundamental understanding of food texture and microstructure and the growing needs in industrial applications. It is this latest development that has led to the production of this book.

The driving force behind the increased activities in food texture modification comes from two very different needs: the growing demands from consumers for healthy tasty food and the urgent needs of properly texturized food for safe food consumption by some specific consumer groups. For the former, food manufacturers have to find a balance between the health benefits and the sensory enjoyment of the food. With fast-changing lifestyles and the abundant availability of food, an oversupply of nutrients leads to negative consequences to human health and therefore becomes a concern to governments as well as consumers. Overweight and obesity are the two most obvious health-related problems as a result of food overconsumption. Food with reduced contents of fat, sugar, and salt has become a preferred choice by many consumers. However, the major technical challenge to the food industry is not to reduce these components, but how to address the balance between the health benefit and sensory enjoyment. As a general principle, a food must be able to provide sensory enjoyment, a key function of the food that has profound influences on one’s psychological and social well-being. A product that provides no sensory pleasing effect simply can hardly be categorized as a food, however healthy it claims to be.

Another very important reason for texture modification is the urgent need of properly texturized food for safe and easy consumption by some specific consumers who have difficulty in consuming normal food, including infants, elderly populations, and hospital patients. Proper modification of food texture is absolutely essential for the safety and well-being of these consumers. In recent years, provision of texture-modified food has been seen as a great business opportunity to the food industry. With a forecasted rapidly growing elderly population, a vast and fast-growing market is predicted for texture-modified food and also for functional ingredients and techniques needed for texture modification. Major food companies have put a lot of resources and efforts into exploring this opportunity, though many technical challenges remain to be solved.

The aforementioned two challenges imply the urgent need of the knowledge and techniques by the food industry on texture modification of food products. The focus of this book is exactly for this need, by addressing various aspects (both technical and practical) of food texture modification and specific needs of disadvantaged consumer groups for texture-modified foods. Unlike other textbooks where knowledge and applications are often the main focus, the primary concern of this book is on consumers’ needs and well-being. Five essential aspects of food texture modification, including ingredients, methodologies, processes, products, and target populations, are arranged into two sequential volumes.

Volume 1 begins with our chapter to introduce the entire concept of texture modification. The chapter outlines the background knowledge of food texture and discusses progress in food texture study from its historical perspective. By setting food texture in its broad context, the chapter also explains the structural aspects of texture creation, texture oral breakdown, and oral appreciation. This is followed by chapters on the use of some novel food ingredients as effective functional components for texture formation and modification. This includes a chapter by Dr. Lin Chen on the food emulsifiers for microstructure creation of dispersed food systems; a chapter by Dr. Christos Ritzoulis and Dr. Panayotis Karayannakidis on food proteins, their structure-forming and stabilizing effects and various factors that influence such functionalities; and a chapter on another very important structural forming ingredient, the enzymes, authored jointly by Drs. Dilek Ercili-Cura, Thom Huppertz, and Prof. Alan Kelly. The third part of volume 1 is on the methodologies for texture creation and modification, which include a chapter by Dr. Shekhar Kadama, Dr. Brijesh Tiwari, and Dr. Colm O’Donnell on the improved thermal processing techniques for much desirable texture; a chapter by Dr. Cheryl Chung and Prof. David J. McClements on the structure and texture of food emulsion products and the use of emulsification technique; a chapter by Dr. Hassan Firoozmand and Prof. Dérick Rousseau on the phase behavior and controlled phase separation for texture modification; and a chapter by Drs. Morten Dille, Kurt Draget, and Magnus Hattrem on the emulsion gels and the use of filler particles for texture modification. The last part of the volume 1 deals with the texture of two major types of food products: a chapter on cereal breakfast and extruded products (by Dr. Frédéric Robina and Prof. Stefan Palzerb); and a chapter on soy-based products, a type of Oriental food growing popular in Western countries (by Dr. Jian Guo and Prof. Xiao-Quan Yang).

Volume 2 has two main focuses: the characterization of food textural properties and the needs and requirements of texture modification of target consumers. The volume begins by a chapter by Dr. Fumiyo Hayakawa on the vocabularies and terminologies of food texture and texture appreciation. This is followed by three chapters on the characterization of the textural properties of food, by taste panel analysis and by quantitative measurements using various instruments. Statistical analysis of taste panel data is discussed in detail by Dr. Peter Ho, whereas instrumental characterization of food texture are dealt with separately by Dr. Andrew Rosenthal on solid and semisolid (or soft solid) foods and by Drs. Guido Sala and Elke Scholten on fluid food. The second part of volume 2 contains topics on the need of texture modification for target populations. This include a chapter on the “free from” food by Drs. Maria Papageorgiou and Adriana Skendi, in which practices and techniques applied for the design and production of gluten-free food are discussed as a typical example. The need of texture modification for elderly populations are addressed in a chapter by Prof. Lisa Duizer and Ms. Katy Field on the weakened sensory capability of elderly and a chapter by Dr. Elisabeth Rothenberg and Prof. Karin Wendin on the practices of texture modification for elderly consumers who have developed difficulties eating and swallowing due to natural aging. Food provisions to hospital patients, in particular those who are diagnosed with dysphagia, are given in the chapter by Dr. Julie Cichero. On the other end of the spectrum, infants and babies also have specific requirements of food texture due to incomplete development of their eating capability. Texture modification of infant food is discussed in detail in a chapter authored jointly by Drs. Sophie Nicklaus, Lauriane Demonteil, and Carole Tournier. Finally, the book concludes with a chapter by Mr. Derek Johnson on the legislation and practices for texture-modified food for institutional food, with a particular focus on the cases of hospital food provision in the United Kingdom.

In addition to a brief abstract and a list of keywords for convenience of literature search, each chapter also has a final section that provides further relevant information so that readers can expand their reading when it is needed. We hope that, by addressing some key aspects of food texture modification, this book provides the knowledge and guidance urgently...