DEVELOPMENTS IN DAIRY CHEMISTRY-3. Lactose and Minor Constituents

Transcription

1 DEVELOPMENTS IN DAIRY CHEMISTRY-3 Lactose and Minor Constituents

2 CONTENTS OF VOLUMES 1 and 2 Volume 1: Proteins 1. Chemistry of Milk Protein. HAROLD E. SWAISGOOD 2. Association of Caseins and Casein Micelle Structure, D. G. SCHMIDT 3. Inter-species Comparison of Milk Proteins. ROBERT JENNESS 4. Biosynthesis of Milk Proteins. T. B. MEPHAM, P. GAYE and J.-C. MERCIER 5. The Enzymatic Coagulation of Milk. D. G. DALGLEISH 6. Heat-induced Coagulation of Milk. P. F. Fox 7. Age Gelation of Sterilized Milks. V. R. HARWALKAR 8. Changes in the Proteins of Raw Milk During Storage. ERNST H. REIMERDES 9. Nutritional Aspects of Milk Proteins. LEIF HAMBRAEUS to. Manufacture of Casein, Caseinates and Co-precipitates. L. L. MULLER 11. Industrial Isolation of Milk Proteins: Whey Proteins. K. R. MARSHALL 12. Functional Properties of Milk Proteins and Their Use as Food Ingredients. C. V. MORR Volume 2: Lipids 1. The Composition and Structure of Milk Lipids. WILLIAM W. CHRISTIE 2. Influence of Nutritional Factors on the Yield, Composition and Physical Properties of Milk Fat. J. C. HAWKE and M. W. TAYLOR 3. Origin of Milk Fat Globules and the Nature of the Milk Fat Globule Membrane. T. W. KEENAN, DANIEL P. DYLEWSKI, TERRY A. WOODFORD and ROSEMARY H.FoRD 4. Physical Chemistry of Milk Fat Globules. P. WALSTRA 5. Physical Properties and Modification of Milk Fat. B. K. MORTENSEN 6. Lipolytic Enzymes and Hydrolytic Rancidity in Milk and Milk Products. H. C. DEETH and C. H. FITZ-GERALD 7. Lipid Oxidation. T. RICHARDSON and M. KORYCKA-DAHL 8. The Nutritional Significance of Lipids. M. 1. GURR

3 DEVELOPMENTS IN DAIRY CHEMISTRY-3 Lactose and Minor Constituents Edited by P. F. FOX Department of Dairy and Food Chemistry, University College, Cork, Republic of Ireland ELSEVIER APPLIED SCIENCE PUBLISHERS LONDON and NEW YORK

4 ELSEVIER APPLIED SCIENCE PUBLISHERS LTD Crown House, Linton Road, Barking, Essex IGll 8JU, England Sole Distributor in the USA and Canada ELSEVIER SCIENCE PUBLISHING CO., INC. 52 Vanderbilt Avenue, New York, NY 10017, USA WITH 97 ILLUSTRATIONS AND 59 TABLES ELSEVIER APPLIED SCIENCE PUBLISHERS LTD 1985 Softcover reprint ofthe hardcover 1 st edition 1985 British Library Cataloguing in Publication Data Developments in dairy chemistry.-(the Developments series) 3 : Lactose and minor constituents I. Dairy produce--analysis I. Fox, P. F. 637'.01'543 SF253 The Library of Congress has cataloged this work as follows: Developments in dairy cbemistry London; New York: Applied Science Publishers, c1982- v.: ill.; 23 cm.-(developments series) ISSN = Developments in dairy chemistry. 1. Dairy products-analysis--collected works. I. Series. [DNAL: I. Dairy products-analysis] SF253.D44 637'.028'7-dcI ISBN-13: e-isbn-13: DOl: / The selection and presentation of material and the opinions expressed in this publication are the sole responsibility of the authors concerned Special regulations for readers in tbe USA This publication has been registered with the Copyright Clearance Center Inc. (Ccq, Salem, Massachusetts. Information can be obtained from the CCC about conditions under which photocopies of parts of this publication may be made in the USA. All other copyright questions, including photocopying outside of the USA, should be referred to the publisher. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Photoset in Malta by Interprint Ltd

5 PREFACE This volume is the third in the series on the chemistry and physical chemistry of milk constituents. Volumes 1 and 2 dealt with the commercially more important constituents, proteins and lipids, respectively. Although the constituents covered in this volume are of less direct commercial importance than the former two, they are nevertheless of major significance in the chemical, physical, technological, nutritional and physiological properties of milk. Lactose, the principal component of the milks of most species, is a rather unique sugar in many respects---it has been referred to as one of Nature's paradoxes. It is also the principal component in concentrated and dehydrated dairy products, many of the properties of which reflect those of lactose. The chemistry and principal properties of lactose have been thoroughly researched over the years and relatively little new information is available on these aspects; this new knowledge, as well as some of the older literature, is reviewed in Chapter 1. Although lactose has many applications in the food, pharmaceutical and chemical industries, not more than 10% of the potentially available lactose is actually recovered as such. Like other sugars, lactose may be modified by a multitude of chemical reagents; some of these are reviewed in Chapter 2 and some applications of the derivatives discussed. The enzymatic hydrolysis of lactose to glucose and galactose has considerable technological as well as nutritional significance, and the recent literature on this subject is reviewed in Chapter 3. Lactose is not digestible by the majority of the world's population, and the current views on this nutritionally important problem are discussed in Chapter 4. A deficiency v

6 VI PREFACE of either of two enzymes involved in the Leloir pathway for galactose metabolism leads to the inability to metabolize galactose produced from lactose (or other galactose-containing sugars) and causes two relatively rare congenital diseases referred to as glactosaemia, the literature on which is reviewed in Chapter 5. Quantitatively, the salts of milk are minor constituents but they playa disproportionately important role in many of the technologically important properties of milk, some of which have been discussed in Volume 1 of this series. Recent literature on the rather complex chemistry of the milk salts per se is reviewed in Chapter 6. Many of the inorganic constituents of milk, some of which are present only at trace levels, are also of very considerable nutritional significance. Since a variety of minerals are required for proper growth and development, and milk is the sole source of these requirements at a critical stage of infant growth, the significance of milk as a source of dietary minerals is discussed in Chapter 7. The flavour/off-flavour of milk and dairy products is undoubtedly technologically important and extremely complex. This topic could easily occupy a full volume in this series but a comprehensive summary is presented in Chapter 8. Many people may regard milk simply as a source of lipids, proteins, carbohydrates and minerals, with very little biological activity as such. This, in fact, is not the case; milk contains a great variety of biologically active species, some of which, e.g. enzymes, may cause undesirable changes in milk and dairy products during storage, while others, e.g. vitamins, immunoglobulins, are of very considerable nutritional and biological significance. Chapters 9, 10 and 11 review the recent literature on the indigenous enzymes in milk, indigenous antibacterial systems and vitamins, respectively. The importance of at least some of the indigenous enzymes and vitamins is well established but the indigenous antibacterial systems may be of much greater significance than considered heretofore, and it is hoped that Chapter 10 will stimulate further research in this area. I wish to thank sincerely the 13 authors who have contributed to this volume; their cooperation and effort made my task as editor rather simple. P. F. Fox

7 CONTENTS List of Contributors IX 1. Lactose: Chemical and Physicochemical Properties 1 P. A. MORRISSEY 2. Developments in the Chemistry and Chemical Modification of Lactose 35 L. A. W. THELWALL 3. Modification of Lactose and Lactose-containing Dairy Products with ~-Galactosidase 69 R. R. MAHONEY 4. Nutritional Significance of Lactose: I. Nutritional Aspects of Lactose Digestion 111 DAVID M. PAIGE and LENORA R. DAVIS 5. Nutritional Significance of Lactose: II. Metabolism and Toxicity of Galactose 133 ALBERT FLYNN 6. The Milk Salts: Their Secretion, Concentrations and Physical Chemistry 143 C. HOLT vii

8 viii CONTENTS 7. Nutritional Aspects of Minerals in Bovine and Human Milks. 183 ALBERT FLYNN and PAUL POWER 8. Flavour of Milk and Milk Products D. J. MANNING and H. E. NURSTEN 9. Indigenous Milk Enzymes BARRY J. KITCHEN 10. The Biological Significance of the Non-immunoglobulin Protective Proteins In Milk: Lysozyme, Lactoferrin, Lactoperoxidase BRUNO REITER 11. Vitamins in Bovine and Human Milks F. M. CREMIN and PAUL POWER Index

9 LIST OF CONTRIBUTORS F. M. CREMIN Department of Nutrition, University College, Cork, Republic of Ireland LENORA R. DAVIS Department of Maternal and Child Health, School of Hygiene and Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, Maryland 21205, USA ALBERT FLYNN Department of Nutrition, University College, Cork, Republic of Ireland C. HOLT Hannah Research Institute, Ayr, Scotland KA6 5HL, UK BARRY J. KITCHEN Gilbert Chandler Institute of Dairy Technology, Werribee, Victoria 3030, Australia. Present address: Cadbury Schweppes Pty Ltd, PO Box 200, Ringwood, Victoria 3134, Australia R. R. MAHONEY Department of Food Science and Nutrition, University of Massachusetts, Amherst, Massachusetts 01003, USA ix

10 x LIST OF CONTRIBUTORS D. J. MANNING Food Research Institute, University of Reading, Shin field, Reading, Berkshire RG2 9AT, UK P. A. MORRISSEY Department of Food Chemistry, University College, Cork, Republic of Ireland H. E. NURSTEN Department of Food Science, University of Reading, Whiteknights, Reading, Berkshire~ RG6 2AP, UK DAVID M. PAIGE Department of Maternal and Child Health, School of Hygiene and Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, Maryland 21205, USA PAUL POWER Department of Nutrition, University College, Cork, Republic of Ireland BRUNO REITER Hon. Research Fellow, Department of Paediatrics, University of Oxford, Oxford OX] 3PD, UK. Present address: 23 Brompton Court, Ray Park Avenue, Maidenhead, Berkshire SL6 8EA, UK L. A. W. THELWALL Tate and Lyle Group Research and Development, Philip Lyle Memorial Research Laboratory, PO Box 68, Whiteknights, Reading, Berkshire RG6 2BX, UK