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Polysaccharides are the subject of heightened interest today, and this book is a concise and fully up-to-date study of the properties of food polysaccharides, describing their interaction with water, the mass-volume-pressure-relationship, various types of mathematical modeling, and the common phenomenology under different combinations of stimuli. New empirical and theoretical equations, which are not often identified with food technologies, are used to support the findings. Polysaccharide Dispersions: Chemistry and Technology in Food is written in a simple, nontechnical style and should be equally comprehensible to the student, the researcher, the plant manager, and the casual observer with only a modest technical background. Key Features* Contains fundamental principles, practical applications, and new discoveries regarding polysaccharides* Presents material in a simple, easy to understand style* Focuses exclusively on the food industry
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POLYSACCHARIDE DISPERSIONS: CHEMISTRY AND TECHNOLOGY IN FOOD
FOOD SCIENCE AND TECHNOLOGY International Series SERIES EDITOR Steve L. Taylor
University of Nebraska ADVISORY BOARD Daryl B. Lund
Cornell University Douglas Archer
Susan K. Harlander
FDA, Washington, D C
Land O'Lakes, Inc.
Jesse F. Gregory, III
Barbara O. Schneeman
University of Florida
University of California, Davis
A complete list of the books in this series appears at the end of the volume.
Polysaccharide Dispersions: Chemistry and Technology in Food Reginald H. Walter Departmentof Food Science and Technology Cornell University Geneva, New York
ACADEMIC PRESS San Diego
London
Boston
New York Sydney Tokyo ii
Toronto
This book is printed on acid-free paper.
Copyright 9 1998 by ACADEMIC PRESS All Rights Reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Academic Press a division of Harcourt Brace & Company 525 B Street, Suite 1900, San Diego, California 92101-4495, USA http://www.apnet.com Academic Press Limited 24-28 Oval Road, London NW1 7DX, UK http://www.hbuk.co.uk/ap/ Library of Congress Card Catalog Number: 97-074420 International Stanrdard Book Number: 0-12-733865-9
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Contents
xi
Preface
Symbols and Abbreviations
xiii
CHAPTER I
Origin and Characteristics of Polysaccharides I. Introduction I II. Physical-Chemical State A. B. C. D. E.
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Molecular Weight and Degree of Polymerization Configurations and Conformations 6 Colloidal Activity 12 Heterogeneity and Homogeneity 18 Polymorphism, Hysteresis, and Syneresis 18
III. Phenomenology 19 IV. Property and Function Modifications A. B. C. D. E. F. G. H.
Acid 2I Alkali 2I Oxidants 22 Enzymes 23 Chemical Substituents ~/-Radiation 25 Micromolecules 25 Homogenization 27
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V. Volume and the Theta Condition Vl. Summary 27
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Contents
CHAPTER 2
The Polysaccharide- Water Interface I. Introduction 29 II. Properties of Water 31 A. The Dielectric Constant B. Ionization 3I C. Activity 32 D. Specific Heat 34 E. Contraction and Expansion F. Surface Tension 34
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III. Polysaccharide-Water Interactions 3s IV. Influences on Polysaccharide-Water Interactions A. Bonding 36 B. Branching 37 C. Ionizing Groups 37 D. Heterogeneity 3'7 V. Polysaccharides as Adsorbents VI. Polysaccharides as Ads