One of the most difficult aspects of compiling a book is to get the right mix of chapter topics. Normally, the compiling editors have the unenviable task of deciding what to put in and what to leave out, especially as many books will only have twelve to fifteen chapters. In this book, many of these issues do not exist as it is a large volume running to twenty-eight chapters and while twenty-eight topics do not exhaust the wide range of available food processing technologies, the compiling editors have come very close to making the ideal selection.

Food process technologies are many and varied, changing in popularity with changing consumption patterns and product popularity. However, a good measure of the relevance of individual unit process operations is the frequency of their occurrence in publically funded research proposals across the world. While process technologists, myself included, will often lament the lack of specific research funding for process technologies, they are nonetheless an essential delivery tool for every food research output and are to be found in many proposals. Even those well-established process technologies covered in this book can be found in ongoing research, demonstrating once again that the correct choices of chapters have been made.

Processing technology is an essential link in the food chain. Without these technologies we do not have food preservation of any sort, we do not have novel products and we have no tools with which to deliver good nutrition to the ever-increasing world population.

It is difficult to classify food processing technologies. Some authors use preservation methods, techniques for dividing raw materials into functional parts and techniques for reformulating them into finished products. This can be problematic as many process operations serve more than one of these functions. In this book, the problem is overcome by the simple use of two sections, one covering conventional or well-established processes and the other covering emerging or novel process technologies.

Section 1 on conventional processing covers all of the processing operations without which a book on process technology would be incomplete. Food preservation processes such as drying, thermal preservation, chilling and freezing are covered in separate chapters as are the combined preservation and cooking technologies of frying, baking and roasting. Not only is baking covered in its own technology-specific chapter but there is also a full chapter devoted to the critical associated process of dough handling and processing. Food deconstruction and reconstruction techniques are well covered in chapters on size reduction, extrusion, extraction, instantizing/ agglomeration and gelling. Indeed, this latter and increasingly important technology is seldom covered in food process technology books and is to be welcomed here.

In most books, the above-mentioned topics would complete the conventional processing section. However, there are further gems of information to be found in this book with chapters on micronization and encapsulation (with a subsection on the use of supercritical fluids in water removal), flavouring and coating technologies (including edible coatings), fortification and impregnation (including osmotic dehydration and vacuum impregnation) and biotransformation in food processing. Once again, it is a pleasant surprise to find such a chapter in a food process technology book as it is seldom covered in such texts. Not only is biotransformation a widely used but not well-known process (cell growth and immobilization, hydrolysis, artificial flavour and sweetener production, etc.), it is a process that will undoubtedly increase in importance over the coming years.

Section 2 covers the topic of novel or newly developing process technologies. It is very easy for a preface writer to become excited about the possibilities offered by such emerging technologies and to thereby imply to the reader that these are somehow more important than the well-established conventional technologies of Section 1. Nothing could be further from the truth. Yes, they are new, exciting and full of promise. However, I am convinced that long into the future, the ‘old reliables’ of heat preservation, chilling, freezing and dehydration technologies will remain the cornerstone of the food process industry right across the world. However, we should not temper our excitement at the prospect of these new technologies.

The first set of chapters in this section cover the new alternative preservation possibilities offered by the use of ultraviolet light (for disinfection, mycotoxin elimination, enzyme inactivation) and infrared preservation and processing (for drying, baking, roasting, blanching and pasteurization). There is a chapter on microwave technologies (including an in-depth consideration of dielectric properties that is also of relevance to other chapters) together with one on radio-frequency heating (its potential uses and underlying science). Another new heating technology showing much promise, ohmic heating, has a chapter in which its underlying science and application possibilities are well covered.

Membrane processing, which, like microwave processing, could justify its place in either section of this book, has its own comprehensive chapter. Its many subforms are examined in detail. Another novel pressure-driven technology, high pressure processing, has a separate chapter covering its heat and mass transfer potentials, its role in microbial inactivation and the problems associated with its application to nonliquid products.

There are three further chapters covering ozone processing (including corona discharge and cold plasma methods, antimicrobial action and potential applications), ultrasonic processing (its science, applications and limitations) and pulsed electric fields (principles, applications and use in cell disintegration).

Nanotechnology, so promising and of such concern, is covered in a separate chapter. The scientific world still awaits the verdict on the food processing applications of such an exciting new technology.

Finally, the topic of image analysis and machine vision is covered in a chapter on its application in intelligent sorting of poultry portions.

So what's missing? I, for one, cannot find it. This is a comprehensive treatment of the current state of knowledge on food process technology and, by the extent of its coverage and the selection of the top authors in each topic, looks set to become the definitive text in its field.

Brian M. McKenna
Emeritus Professor of Food Science, UCD – University College Dublin