Food Engineering Series

Transcription

1 Food Engineering Series Series Editor Gustavo V. Barbosa-Cánovas, Washington State University, USA Advisory Board José Miguel Aguilera, Catholic University, Chile Xiao Dong Chen, Monash University, Australia J. Peter Clark, Clark Consulting, USA Richard W. Hartel, University of Wisconsin, USA Albert Ibarz, University of Lleida, Spain Jozef Kokini, Purdue University, USA Michèle Marcotte, Agriculture & Agri-Food Canada, Canada Michael McCarthy, University of California, USA Keshavan Niranjan, University of Reading, United Kingdom Micha Peleg, University of Massachusetts, USA Shafiur Rahman, Sultan Qaboos University, Oman M. Anandha Rao, Cornell University, USA Yrjö Roos, University College Cork, Ireland Walter L. Spiess, University of Karlsruhe, Germany Jorge Welti-Chanes, Monterrey Institute of Technology, Mexico For further volumes:

2 M. Anandha Rao Rheology of Fluid, Semisolid, and Solid Foods Principles and Applications Third Edition 1 3

3 M. Anandha Rao Department of Food Science Cornell University Geneva, NY, USA ISSN ISBN ISBN (ebook) DOI / Springer New York Heidelberg Dordrecht London Library of Congress Control Number: Springer Science+Business Media New York 1999, 2007, 2014 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (

4 Preface to the Third Edition Following the very good acceptance of the second edition of Rheology of Fluid and Semisolid Foods: Principles and Applications, it is an honor and a pleasure to present the third edition. Again, the book is divided into eight chapters: Chap. 1 Introduction: Food Rheology and Structure, Chap. 2 Flow and Functional Models for Rheological Properties of Fluid Foods, Chap. 3 Measurement of Flow and Viscoelastic Properties, Chap. 4 Rheology of Food Gum and Starch Dispersions, Chap. 5 Rheological Behavior of Processed Fluid and Semisolid Foods, Chap. 6 Rheological Behavior of Food Gels, Chap. 7 Role of Rheological Behavior in Sensory Assessment of Foods and Swallowing, and Chap. 8 Application of Rheology to Fluid Food Handling and Processing. Several changes have been incorporated in this third edition and these revisions should help readers better appreciate the important role that rheological properties play in food science, as well as to utilize them to characterize foods. The new topics covered in the second edition have been listed in the preface of that edition. In the third edition, the contents of the second edition have been left intact. Additional topics covered in the 3rd edition include: In Chap. 1, a section on microstructure in general and on nanometer-scale milk protein fibrils together with their quantitative characterization in terms of persistence and contour lengths. In Chap. 2, a section on the phase diagram of a colloidal glass of hard spheres and its relationship to milk protein dispersions were added. Additions in Chap. 3 include, sections on Microrheology, including detailed descriptions of single particle and multiparticle micro rheological measurements, and Diffusive Wave Spectroscopy. In Chap. 4, a short section on starch spherulites was added. Because the Bostwick consistometer is used extensively for quality control of pureed foods, e.g., baby foods, in Chap. 5, a section on correlation of Bostwick consistometer data in terms of property-based dimensionless groups was added. Chapter 6 contains a new section on the effect of calcium on the morphology and functionality of whey protein nanometer-scale fibrils. In Chap. 7, it was pointed out that the roles of tribology and rheology are considered for the sensory perception of foods. v

5 vi Preface to the Third Edition My association with the Riddet Institute, Massey University, NZ, helped shape the changes I made in this third edition. I thank Prof. Harjinder Singh for inviting me to work at the Riddet Institute, My special thanks to Dr. Simon Loveday for valuable collaboration. Again, the mistakes in this book are mine and I hope that many of them can be corrected in a future edition. Department of Food Science Cornell University Geneva, NY, USA May 18, 2013 M. Anandha Rao, PhD

6 Contents 1 Introduction: Food Rheology and Structure... 1 Stress and Strain Tensors... 3 Viscometric Properties... 4 Shear Stress Shear Rate Relationships... 5 Units in Rheological Measurement... 5 Types of Fluid Flow Behavior... 6 Newtonian Behavior... 7 Shear-Thinning Behavior... 8 Yield Stress... 8 Shear-Thickening Behavior... 8 Time-Dependent Behavior... 8 Apparent Viscosity... 9 Intrinsic Viscosity... 9 Stress Strain Behavior of Solid Foods Linear Viscoelasticity Linear Viscoelasticity in Differential Form Length Scale of Food Molecules and Foods Phase Transitions in Foods Glass Transition in Foods Appendix 1-A Momentum and Heat Transport Equations for Incompressible Fluids References Suggested Reading Flow and Functional Models for Rheological Properties of Fluid Foods Time-Independent Flow Behavior Newtonian Model Power Law Model Herschel Bulkley Model Casson Model Quemada Model vii

7 viii Contents Apparent Viscosity Shear Rate Relationships of Shear-Thinning Foods Cross and Carreau Models Models for Time-Dependent Flow Behavior Weltman Model Tiu Boger Model Role of Solids Fraction in Rheology of Dispersions Colloidal Glass Rheology of Protein Dispersions Modulus of Gels of Fractal Floes Effect of Soluble and Insoluble Solids Concentration on Apparent Viscosity of Foods Peclet Number of Dispersions Emulsions Effect of Temperature on Viscosity Combined Effect of Concentration and Temperature Mixing Rules for two Component Blends Treatment of Rheological Data Using Models References Measurement of Flow and Viscoelastic Properties Rotational Viscometers Concentric Cylinder Viscometer Parallel Disk Geometry Mixer Viscometer Yield Stress of Foods Using a Vane Structural Characteristics of Dispersions Torsion Gelometer for Solid Foods Pressure-Driven Flow Viscometers Capillary/Tube Viscometer Sample Calculation, Test No Glass Capillary Viscometer Slit (Channel) Rheometer Miscellaneous Viscometers Viscosity Measurement at High Temperatures In-Plant Measurement of Flow Behavior of Fluid Foods Tomographic Techniques Vibrational Viscometers Extensional Flow Viscometry Uniaxial Extension Biaxial Extension Planar Extension Cogswell s Treatment of Extensional Flow Measurement of Viscoelastic Behavior of Fluid Foods Oscillatory Shear Flow Types of Dynamic Rheological Tests

8 Contents ix Axial Motion between Coaxial Cylinders (Segel-Pochettino Geometry) Vibrating Sphere Rheometer Mechanical Models of Dynamic Rheological Data Time-Temperature Superposition Time-Temperature Superposition of Locust Bean (LB) Gum and Pectin Dispersions Critical Stress and Strain Creep-Compliance Behavior Transient Viscoelastic Flow Stress-Relaxation Static Measurement of Modulus Relationship among Rheological Parameters Deborah Number Microrheology Single-Particle Microrheology Diffusive Wave Spectroscopy (DWS) Multiparticle Video Microscopy Microstructure from Microrheology Commercial Rheometers Some Precautions with Foods Appendix 3 A Analysis of Flow in a Concentric Cylinder Geometry Appendix 3 B Analysis of Steady Laminar Fully Developed Flow in a Pipe Appendix 3 C Analysis of Flow in a Cone-Plate Geometry References Rheology of Food Gum and Starch Dispersions Rheology of Food Gum Dispersions Rheological Models for Apparent Viscosity Shear Rate Data Rheological Properties of Binary Mixtures of Equal Concentration Effect of Biopolymer Concentration on Zero-Shear Viscosity Concentration Dependence of the Zero-Shear Viscosity of Gum Mixtures Concentration Dependence of the Zero-Shear Viscosity of Amylopectin Solutions Viscoelastic Behavior of Food Gum Dispersions Cox Merz Rule for Biopolymer Dispersions Constitutive Equations Based on Molecular Structure Rheology of Heated Starch Dispersions Starch Granules and Composition Starch Gelatinization Gelatinization Temperature and Extent of Gelatinization

9 x Contents Viscous and Viscoelastic Properties During Heating of Starch Dispersions Model of Dolan et al Model for η*-temperature Data (Yang and Rao 1998) Rheological Properties of Gelatinized Starch Dispersions Rheology of Starch Dispersions with Intact Granules Role of Particles in Shear-Thickening Nonfood Dispersions Size Distribution of Intact Starch Granules Antithixotropic Behavior of Cross-Linked Starch Dispersions Starch Granule Mass Fraction and Viscosity Mass Fraction versus Relative Viscosity Effect of Starch Concentration Yield Stress and Structural Characteristics of Dispersions Effect of Temperature on Flow Behavior Dynamic Rheological Behavior of Starch Dispersions Effect of Particle Characteristics on Modulus Role of Continuous and Dispersed Phases on Viscoelastic Properties of Starch Dispersions Cross-Linked Waxy Maize Starch Dispersions % Tapioca Starch Dispersions Effect of Sugar on Rheology of Starch Dispersion Rheological Behavior of Starch Protein Dispersions Gluten/Starch Soy Protein/Corn Starch Cowpea Protein/Cowpea Starch Whey Protein Isolate/Cross-Linked Waxy Maize Starch Dispersions Rheology of Starch Gum Dispersions References Rheological Behavior of Processed Fluid and Semisolid Foods Fruit Juices and Purees: Role of Soluble and Insoluble Solids Role of PF Insoluble Solids Size Distribution of Fruit Juice Solids Serum Viscosity of PF Dispersions Rheological Properties of Frozen Concentrated Orange Juice (FCOJ) Viscoelastic Properties of Tomato Concentrates Rheological Properties of Tomato Pastes Role of Composition of Tomato Pastes Model for Apparent Viscosity of PF Dispersions Yield Stress of Structured Food Products Correlation of Bostwick Consistometer Data in Terms of Property-Based Dimensionless Groups

10 Contents xi Rheological Properties of Chocolate Rheology of Milk and Milk Concentrates Rheology of Mayonnaise, Salad Dressing, and Margarine Stress Overshoot Data of Mayonnaise Creep-Compliance Behavior of Mayonnaise Rheology of Salad Dressings Processed Foods as Soft Materials Structural Analyses of Food Dispersions Role of Suspended Particles in Soy Milk Structural Components of Yield Stress Texture Map Based on Vane Yield Stress High Pressure Processing of Milk and Milk Proteins Kinetics of Thermal and Pressure-induced Changes Mechanisms of Heat-induced and Pressure-induced Changes Structural Changes in Milk Proteins Effect of Pressure Release Rates Ultrahigh Pressure Homogenization of Milk Structural Changes due to UHPH Treatment Myofibrillar Proteins Soy Proteins Egg Proteins Appendix 5 A Literature Values of Rheological Properties of Foods References Rheological Behavior of Food Gels Rheological Tests to Evaluate Properties of Gel Systems Mechanisms of Gelation Classification of Gels Theoretical Treatment of Gels Rubber Elasticity Cascade Theory Percolation Theory Fractal Model Gel Point and Sol-Gel Transition by Rheological Measurements Rheological Definition of Gel Point Extrapolation of G Value Critical Viscoelastic Behavior at the Gelation Threshold Influence of Concentration and Temperature on Gel Time Evaluation of Structure Development during Biopolymer Gelation Effect of Temperature on the Rate of Structure Formation and Kinetic Data Structure Development Rate

11 xii Contents Kinetics of Gelation Evaluation of Structure Loss during Melting/Softening of Biopolymer Gels Mixed Polymer Gels Polysaccharide-Polysaccharide Mixtures Protein-Polysaccharide Mixtures Biopolymer Mixtures under Flow Fields Phase Diagrams and Modeling Low-Fat Spreads STARCH GELS Effect of calcium on the morphology and functionality of whey protein nanofibrils References Role of Rheological Behavior in Sensory Assessment of Foods and Swallowing Stimuli for Evaluation of Viscosity Stimuli Associated with Tilting Container and Stirring Stimuli Associated with Oral Evaluation of Viscosity Comparison of Oral and Nonoral Assessment Techniques Sensory Assessment of Viscosity of Gum Dispersions Perceived Thickness of Gum Dispersions Spreadability: Using Force and Under Normal Gravity Application of Fluid Mechanics Fluid Mechanics of Spreadability Creaminess, Smoothness, and Slipperiness Role of Size, Shape, and Hardness of Particles Role of Rheology in Perception of Flavor and Taste Role of Hydrocolloid Concentration Engineering Approach Role of Rheology in Swallowing A Model of the Swallowing Process Flow Rate and Cumulative Volume for a Newtonian Fluid Effect of Fluid Rheology on the Swallowing Process Effect of Rheology on Time to Swallow 1.0 ml References Application of Rheology to Fluid Food Handling and Processing Velocity Profiles in Tubes Energy Requirements for Pumping Mechanical Energy Balance Equation Pump Selection and Pipe Sizing Pump Discharge Pressure Power Requirements for Pumping

12 Contents xiii Power Consumption in Agitation Role of Flow Behavior in Agitation Estimation of the Constant k s of an Agitator Residence Time Distribution in Aseptic Processing Systems Interpretation of RTD Data Sizing Holding Tube Length Experimental RTD Data Helical Flow Heat Transfer to Fluid Foods Thermorheological Models Thermorheogy of Starch Dispersions Model of Dolan et al. (1989) Continuous Flow Sterilization Heat Transfer to Shear-Thinning Fluids Physical Model of Non-Isothermal Laminar Flow Tube Sterilizer Continuous Sterilization of a Fluid Food Containing Starch Analysis of the Heating Section Analysis of Cooling Section Length of Heating Section Influence of Rheological Behavior on the Heating Length Role of Rheology in Thermal Processing of Canned Foods Heat Penetration Parameters Numerical Solution of Transport Equations Estimated Heat Penetration Parameters and Broken Heating Phenomena Heat Transfer to a Starch Dispersion in an Intermittently Rotated Can Intermittent Rotation Profile Thermorheological Behavior of the Model Food Empirical Correlations for Heat Transfer to Fluids Flowing in Tubes Newtonian Fluid Power Law Fluid Empirical Correlations for Heat Transfer to Canned Fluids References Index