This volume includes 28 contributions to the Toyoichi Tanaka Memorial Symposium on Gels which took place at Arcadia Ichigaya on September 10th-12th, 2008. The contributions from leading scientists cover a broad spectrum of topics concerning: Structure and Functional Properties of Gels - Swelling of Gels - Industrial and Biomedical Application. The symposium was held in the style of Faraday Discussions, which stimulated the active discussion. After the symposium, each manuscript was rewritten based on the discussion and the critical review. Since the research on gels is becoming more and more important both for academia and industry, this book will be an essential source of information.

This book covers various molecular, metal-organic, dynamic covalent, polymer and other gels, focusing on their driving interactions, structures and properties. It consists of six chapters demonstrating interesting examples of these gels, classified by the type of driving interaction, and also discusses the effect of these interactions on the gels’ structures and properties. The book offers an interesting and useful guide for a broad readership in various fields of chemical and materials science.

It is now well recognised that the texture of foods is an important factor when consumers select particular foods. Food hydrocolloids have been widely used for controlling in various food products their viscoelasticity, emulsification, gelation, dispersion, thickening and many other functions. An international journal, FOOD HYDROCOLLOIDS, launched in 1986 has published a number of stimulating papers, and established an active forum for promoting the interaction between academics and industrialists and for combining basic scientific research with industrial development. Although there have been various research groups in many food processing areas in Japan, such as fish paste (kamaboko, surimi), soybean curd (tofu), agar jelly dessert, kuzu starch jelly, kimizu (Japanese style mayonnaise), their activities have been conducted in isolation of one another. The interaction between the various research groups operating in the various sectors has been weak. Symposia on food hydrocolloids have been organised on several occasions in Japan since 1985. Professor Glyn O. Phillips, the Chief Executive Editor of FOOD HYDROCOLLOIDS, suggested to us that we should organise an international conference on food hydrocolloids. We discussed it on many occasions, and eventually decided to organise such a meeting, and extended the scope to include recent development in proteinaceous hydrocolloids, and their nutritional aspects, in addition to polysaccharides and emulsions.

Presenting a unique perspective on state-of-the-art physical gels, this interdisciplinary guide provides a complete, critical analysis of the field and highlights recent developments. It shows the interconnections between the key aspects of gels, from molecules and structure through to rheological and functional properties, with each chapter focusing on a different class of gel. There is also a final chapter covering innovative systems and applications, providing the information needed to understand current and future practical applications of gels in the pharmaceutical, agricultural, cosmetic, chemical and food industries. Many research teams are involved in the field of gels, including theoreticians, experimentalists and chemical engineers, but this interdisciplinary book collates and rationalises the many different points of view to provide a clear understanding of these complex systems for researchers and graduate students.

A gel is a state of matter that consists of a three-dimensional cross-linked polymer network and a large amount of solvent. Because of their structural characteristics, gels play important roles in science and technology. The science of gels has attracted much attention since the discovery of the volume phase transition by Professor Toyoichi Tanala at MIT in 1978. MDPI planned to publish a Special Issue in Gels to celebrate the 40th anniversary of this discovery, which received submissions of 13 original papers and one review from various areas of science. We believe that readers will find this Special Issue informative as to the recent advancements of gel research and the broad background of gel science.

This volume contains a series of papers originally presented at the Symposium on Polymer Gels organized and sponsored by the Research Group on Polymer Gels,The Society of Polymer Science of Japan and co-sponsored by the Science and Technology Agency (ST A) and MIT!, Japan. The Symposium took place at Tsukuba Science City on 18th and 19th September, 1989. Recognized experts in their fields were invited to speak and there was a strong attendance from government, academic and industrial research centers. The purpose of the Symposium was to review the state of the art and to present and discuss recent progress in the understanding of the behavioral properties of polymer gels and their application to biomedical, environmental and robotic fields. Most of the papers and related discussions concentrated on the swelling behavior of hydrogels and chemomechanical systems, both artificial and naturally occurring, in which external stimuli of a physical or chemical nature control energy transformation or signal transduction. The recent great interest in chemomechanical systems based on polymer gels has stimulated considerable effort towards the development of new sensors and actuators, controllable membrane separation processes, and delivery systems in which the functions of sensing, processing and actuation are all built into the polymeric network device. Artificial chemomechanical systems, through the use of environmentally sensitive polymer gels, are emerging as interesting materials for mimicking basic processes previously only confined to the biological world, and commercially viable applications are also foreseen in the not-too-distant future.

Food proteins constitute a diverse and complex collection of biological macro molecules. Although contributing to the nutritional quality of the foods we con sume, proteins also act as integral components by virtue of their diverse functional properties. The expression of these functional properties during the preparation, processing and storage of foods is largely dictated by changes to the structure or structure-related properties of the proteins involved. Therefore, germane to the optimal use of existing and future food protein sources is a thorough understanding of the nature of the relationships between structure and function. It is the goal of this book to aid in better defining these relationships. Two distinct sections are apparent: firstly, those chapters which address struc ture-function relationships using a variety of food systems as examples to demonstrate the intricacies of this relationship, and secondly, those chapters which discuss techniques used to either examine structural parameters or aid in establishing quantitative relationships between protein structure and function. The editors would like to thank all contributors for their assistance, co-operation and, above all, their patience in putting this volume together, and the following companies/organizations for their financial support without which it would not have been the success it was: Ault Foods Limited, Best Foods Canada Limited, Natural Sciences and Engineering Research Council of Canada, Ontario Ministry of Agriculture and Food, Quest International Canada Inc., and University of Guelph. R.Y.Y. R.LJ.