Food Process Engineering and Technology

1 FOOD Process Engineering AND TECHNOLOGYFood Science and TechnologyInternational SeriesSeries EditorSteve L. TaylorUniversity of Nebraska Lincoln, USAA dvisory BoardKen BuckleThe University of New South Wales, AustraliaMary Ellen CamireUniversity of Maine, USAR oger ClemensUniversity of Southern California, USAH ildegarde HeymannUniversity of California Davis, USAR obert HutkinsUniversity of Nebraska Lincoln, USARon S. JacksonQuebec, CanadaHuub LelieveldBilthoven, The NetherlandsDaryl B. LundUniversity of Wisconsin, USAC onnie WeaverPurdue University, USARon WrolstadOregon State University, USAA complete list of books in this series appears at the end of this volumeFood Process Engineering and TechnologyZeki BerkProfessor (Emeritus)

2 Department of Biotechnology and Food Engineering TECHNION Israel Institute of Technology Israel AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK OXFORDPARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYOA cademic Press is an imprint of ElsevierAcademic Press is an imprint of Elsevier30 Corporate Drive, Suite 400, Burlington, MA 01803, USA32 Jamestown Road, London NW1 7BY, UK525 B Street, Suite 1900, San Diego, CA 92101-4495, USA360 Park Avenue South, New York, NY 10010-1710, USAF irst edition 2009 Copyright 2009 Elsevier Inc.

3 All rights reservedNo 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 Permissions may be sought directly from Elsevier s Science & Technology Rights Department in Oxford, UK: phone ( 44) (0) 1865 843830; fax ( 44) (0) 1865 853333; email: Alternatively visit the Science and Technology Bookswebsite at for further informationNoticeNo responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein.

4 Because of rapid advances in the medical sciences, in particular, independent verifi cation of diagnoses and drug dosages should be madeLibrary of Congress Cataloging in Publication DataA catalog record for this book is available from the Library of CongressBritish Library Cataloguing in Publication DataA catalogue record for this book is available from the British LibraryISBN: 978-0-12-373660-4 For information on all Academic Press publications visit our web site at by Charon Tec Ltd., A Macmillan Company. ( )Printed and bound in the United States of America09 10 11 12 13 10 9 8 7 6 5 4 3 2 1To my studentsContents Introduction Food is Life.

5 1 1 Physical properties of food materials .. 7 Introduction .. 7 Mechanical properties .. 8 1 . 2 . 1 D e fi nitions .. 8 Rheological models .. 9 Thermal properties .. 10 Electrical properties .. 11 Structure .. 11 Water activity .. 13 The importance of water in foods .. 13 Water activity, defi nition and determination .. 14 Water activity: prediction.

6 14 Water vapor sorption isotherms .. 16 Water activity: effect on food quality and stability .. 19 Phase transition phenomena in foods .. 19 The glassy state in foods .. 19 Glass transition temperature .. 20 2 Fluid fl ow .. 27 Introduction .. 27 Elements of fl uid dynamics .. 27 Viscosity .. 27 Fluid fl ow regimes .. 28 Typical applications of Newtonian laminar fl ow.

7 30 Laminar fl ow in a cylindrical channel (pipe or tube) .. 30 Laminar fl uid fl ow on fl at surfaces and channels .. 33 Laminar fl uid fl ow around immersed particles .. 34 Fluid fl ow through porous media .. 36 Turbulent fl uid fl ow .. 36 Turbulent Newtonian fl uid fl ow in a cylindrical channel(tube or pipe) .. 37 Turbulent fl uid fl ow around immersed particles.

8 39 Flow properties of fl uids .. 40 Types of fl uid fl ow behavior .. 40 Non-Newtonian fl uid fl ow in pipes .. 41 Transportation of fl uids .. Energy relations, the Bernoulli Equation .. 43 Pumps: Types and operation .. 46 Pump selection .. 52 Ejectors .. 55 Piping .. 56 Flow of particulate solids (powder fl ow).

9 56 Introduction .. 56 Flow properties of particulate solids .. 57 Fluidization .. 62 Pneumatic transport .. 65 3 Heat and mass transfer, basic principles .. 69 Introduction .. 69 Basic relations in transport phenomena .. 69 Basic laws of transport .. 69 Mechanisms of heat and mass transfer .. 70 Conductive heat and mass transfer.

10 70 The Fourier and Fick laws .. 70 Integration of Fourier s and Fick s laws for steady-state conductive transport .. 71 Thermal conductivity, thermal diffusivity and molecular diffusivity .. 73 Examples of steady-state conductive heat and mass transfer processes .. 76 Convective heat and mass transfer .. 81 Film (or surface) heat and mass transfer coeffi cients.