Libro Reologia

RHEOLOGICAL METHODS IN FOOD PROCESS ENGINEERING
Second Edition

James F. Steffe, Ph.D., P.E.
Professor of Food Process Engineering Dept. of Food Science and Human Nutrition Dept. of Agricultural Engineering Michigan State University

Freeman Press
2807 Still Valley Dr. East Lansing, MI 48823 USA

Prof. James F. Steffe 209 Farrall Hall Michigan State University East Lansing, MI48824-1323 USA Phone: FAX: E-mail: URL: 517-353-4544 517-432-2892 steffe@msu.edu www.egr.msu.edu/~steffe/

Copyright  1992, 1996 by James F. Steffe. All rights reserved. No part of this work 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 author.Printed on acid-free paper in the United States of America Second Printing

Library of Congress Catalog Card Number: 96-83538

International Standard Book Number: 0-9632036-1-4

Freeman Press 2807 Still Valley Dr. East Lansing, MI 48823 USA

Table of Contents
Preface Chapter 1. Introduction to Rheology 1.1. Overview...................................................................................... 1.2. Rheological Instruments for Fluids .......................................... 1.3. Stress and Strain .......................................................................... 1.4. Solid Behavior ............................................................................. 1.5. Fluid Behavior in Steady Shear Flow ....................................... 1.5.1. Time-IndependentMaterial Functions ............................ 1.5.2. Time-Dependent Material Functions ............................... 1.5.3. Modeling Rheological Behavior of Fluids ....................... 1.6. Yield Stress Phenomena ............................................................. 1.7. Extensional Flow ......................................................................... 1.8. Viscoelastic MaterialFunctions ................................................ 1.9. Attacking Problems in Rheological Testing ............................ 1.10. Interfacial Rheology ................................................................. 1.11. Electrorheology ......................................................................... 1.12. Viscometers for Process Control and Monitoring ................ 1.13.Empirical Measurement Methods for Foods ........................ 1.14. Example Problems .................................................................... 1.14.1. Carrageenan Gum Solution ............................................. 1.14.2. Concentrated Corn Starch Solution ................................ 1.14.3. Milk Chocolate.................................................................. 1.14.4. Falling Ball Viscometer for Honey ................................. 1.14.5. Orange Juice Concentrate ................................................ 1.14.6. Influence of the Yield Stress in Coating Food ............... Chapter 2. Tube Viscometry 2.1. Introduction ................................................................................. 2.2. Rabinowitsch-Mooney Equation.............................................. 2.3. Laminar Flow Velocity Profiles ................................................ 2.4. Laminar Flow Criteria ................................................................ 2.5. Data Corrections ......................................................................... 2.6. Yield Stress Evaluation.............................................................. 2.7. Jet Expansion ............................................................................... 2.8. Slit Viscometry ............................................................................ 2.9. Glass Capillary (U-Tube) Viscometers .................................... 2.10. Pipeline Design Calculations .................................................. 2.11. Velocity Profiles In...