Book reviews 165

areas covered are: quality control in catering, effective communication and information transfer, the training of operatives as well as manage- ment, hospitality management, education and the industry, and labour versus technology.

On the whole, the book provides a wealth of information on modern catering technology and is an invaluable addition to the library of any major catering establishment or institution involved in catering educa- tion and training.

D. Man

Enzymic Hydrolysis of Food Proteins. By Jens Adler-Nissen, Elsevier Applied Science Publishers, London, 1986, xxii+404 pp. ISBN 0 85334 386 1. Price: g57.00.

This book contains the substance of a dissertation submitted by the author for the award of the Danish Doctorate of Engineering.

The first chapter provides a brief but useful introduction to enzymic hydrolysis of food proteins as well as a concise background for this volume. This is followed by a review of some fundamental aspects of food protein hydrolysis in chapter 2, including the very important quantity - the degree of hydrolysis (DH) - as a measure of controlled protein hydrolysis, which is generally used throughout this book. In chapters 3 and 4, the existing literature on food protein hydrolysis by the action of isolated proteolytic enzymes is extensively reviewed. The former chapter deals with some general issues and the latter with specific areas of interest, namely, the well known problem of bitter peptides, enzymic hydrolysates of soya protein and developments in protein hydrolysis processes and associated products using various protein sources. A comprehensive and detailed survey of methodologies for protein hydrolysis and-of methods for characterising protein hydroly- sates is given in chapter 5. The first part of chapter 6 contains a critical examination and calibration of the two methods, pH-stat technique and osmometry, which are employed to follow the controlled protein hydrolysis reaction. The use of these two methods as an important part of the empirical characterisation of enzymes and substrates under application conditions is then exemplified in the second part of this

166 Book reviews

chapter. In chapter 7 the kinetic aspects of food protein hydrolysis are discussed with a view to understanding two major issues. The first is the universally observed downward curvature of protein hydrolysis curves, and the second is the relationship between the state of denaturation of a given substrate and the molecular weight distribution of the hydrolysate. Chapters 8 and 9 are concerned with the quantitative treatment of protein hydrolysis experiments, the 8(h) method and mass balance calculations, respectively. Chapter 10 is devoted to an in-depth discus- sion of industrial enzymic protein hydrolysis processes, much of which is illustrated and exemplified by the production, properteis and use of iso- electric soluble soya protein hydrolysate (ISSPH). The book, being a dis- sertation, ends naturally with a discussion in the concluding chapter of the implications of the foregoing chapters, in particular chapters 6, 7,8 and 10, together with consideration of the current theoretical understanding of the hydrolysis of protein (chapter 3) and of the causes of bitterness (chapter 4).

The author has clearly demonstrated that there are a number of practical ways to minimise the technical/scientific obstacles which have hitherto prevented the wider use of protein hydrolysates as food ingredients.

Overall, the book represents an admirable piece of hard work which contains a wealth of previously unpublished information. However, because of its specialist coverage and price, the book may not appeal to the general reader.

D. Man