physical principles of food preservation second edition revised and expanded food science and technology

PHYSICAL
PRINCIPLES
PRESERVATION
OF
FOOD
SECOND
EDITION,
REVISED
AND
EXPANDED
MARCUS
KAREL
Massachusetts Institute
of
Technology
Cambridge, Massachusetts,
U.S.A.
DARVL
B.
LUND
University
of
Wisconsin-Madison
Madison, Wisconsin,
U.
S.
A.
MARCEL
MARCEL DEKKER,
INC.

DEKKER
NEW
YORK
BASEL
The first edition of this book was published as Principles of Food Science: Part II,
Physical Principles of Food Preservation, Marcus Karel, Owen R. Fennema, and Daryl B.
Lund, 1975 (Marcel Dekker, Inc.), ISBN 0-8247-6322-X.
Although great care has been taken to provide accurate and current information, neither the
author(s) nor the publisher, nor anyone else associated with this publication, shall be liable
for any loss, damage, or liability directly or indirectly caused or alleged to be caused by
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trademarks and are used only for identification and explanation without intent to infringe.
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ISBN: 0-8247-4063-7
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PRINTED IN THE UNITED STATES OF AMERICA
FOOD
SCIENCE
AND TECHNOLOGY
A
Series
of
Monographs,
Textbooks,
and
Reference
Books
EDITORIAL BOARD
Senior Editors
Owen
R.
Fennema
University of Wisconsin-Madison
Y. H. Hui
Science Technology System
Marcus Karel

Rutgers University (emeritus)
Pieter Walstra
Wageningen University
John
R.
Whitaker
University of California-Davis
Additives
P.
Michael Davidson
University of Tennessee-Knoxville
Dairy science
James L. Steele
University of Wisconsin-Madison
Flavor chemistry and sensory analysis
John
H.
Thorngate
111
University
Food engineering
Daryl
9.
Lund
University bf Wisconsin-Madison
Food lipids and flavors
David
9.
Min
Ohio State University

Food profeins/food chemistry
Rickey Y. Yada
University of Guelph
Health and disease
Seppo
Salminen
University of Turku, Finland
Nutrition and nutraceuticals
Mark Dreher
Mead Johnson Nutritionals
Phase transition/food microstructure
Richard
W.
Hartel
University of
Processing and preservation
Gustavo
V.
Barbosa-Canovas
Washington
Safefy and toxicology
Sanford Miller
University of Texas-Austin
of California-Davis
Wisconsin-Madison
State University-Pullman
1.
Flavor Research: Principles and Techniques,
R.
Teranishi,

1.
Horn-
stein,
P.
Issenberg, and
€.
L.
Wick
2.
Principles of Enzymology for the Food Sciences,
John R. Whitaker
3.
Low-Temperature Preservation of Foods and Living Matter,
Owen
R.
Fennema, William D. Powrie, and Elmer H. Marth
4.
Principles of Food Science
Part
I:
Food Chemistry,
edited by Owen
R.
Fennema
Part
11:
Physical Principles
of
Food
Preservation,

Marcus Karel, Owen
R.
Fennema, and Daryl
6.
Lund
5.
Food Emulsions,
edited by Stig
E.
Friberg
6.
Nutritional and Safety Aspects of Food Processing,
edited by Steven
R.
Tannenbaum
7.
Flavor Research: Recent Advances,
edited
by
R. Teranishi, Robert
A.
Flath, and Hiroshi Sugisawa
8.
Computer-Aided Techniques in Food Technology,
edited by Israel
SWUY
9.
Handbook of Tropical Foods,
edited by Harvey T. Chan
10. Antimicrobials in Foods,

edited by Alfred Larry Branen and P. Michael
Davidson
11. Food Constituents and Food Residues: Their Chromatographic
Determination,
edited by James F. Lawrence
12. Aspartame: Physiology and Biochemistry,
edited by Lewis
D.
Stegink
and L. J. Filer, Jr.
13. Handbook
of
Vitamins: Nutritional, Biochemical, and Clinical Aspects,
edited by Lawrence
J.
Machlin
14.
Starch Conversion Technology,
edited by
G.
M.
A.
van Beynum and J.
A. Roels
15. Food Chemistry: Second Edition, Revised and Expanded,
edited by
Owen R. Fennema
16. Sensory Evaluation of Food: Statistical Methods and Procedures,
Mi-
chael O'Mahony

17. Alternative Sweeteners,
edited by Lyn O'Brien Nabors and Robert C.
Gelardi
18.
Citrus Fruits and Their Products: Analysis and Technology,
S.
V.
Ting
and Russell
L.
Rouseff
19.
Engineering Properties of Foods,
edited by M.
A.
Rao and
S. S.
H.
Rizvi
20. Umami: A Basic Taste,
edited by Yojiro Kawamura and Motley R.
Kare
21. Food Biotechnology,
edited by Dietrich Knorr
22. Food Texture: Instrumental and Sensory Measurement,
edited by
Howard R. Moskowitz
23. Seafoods and Fish Oils in Human Health and Disease,
John
E.

Kinsella
24. Postharvest Physiology of Vegetables,
edited by J. Weichmann
25.
Handbook of Dietary Fiber: An Applied Approach,
Mark L. Dreher
26. Food Toxicology, Parts A and B,
Jose M. Concon
27. Modern Carbohydrate Chemistry,
Roger
W.
Binkley
28. Trace Minerals in Foods,
edited by Kenneth
T.
Smith
29.
Protein Quality and the Effects of Processing,
edited by R. Dixon
Phillips and John
W.
Finley
30. Adulteration of Fruit Juice Beverages,
edited by Steven Nagy, John
A.
Atfaway, and Martha
E.
Rhodes
31. Foodborne Bacterial Pathogens,
edited by Michael P. Doyle

32. Legumes: Chemistry, Technology, and Human Nutrition,
edited by
Ruth H. Maffhews
33. Industrialization of Indigenous Fermented Foods,
edited by Keith H.
Steinkra
us
34. International Food Regulation Handbook: Policy
0
Science Law,
edited by Roger
D.
Middlekauff and Philippe Shubik
35. Food Additives,
edited by
A.
Larry Branen,
P.
Michael Davidson. and
Seppo Salminen
36. Safety of Irradiated Foods,
J. F. Diehl
37. Omega3 Fatty Acids in Health and Disease,
edifed by Robert
S.
Lees
and Marcus Karel
38. Food Emulsions: Second Edition, Revised and Expanded,
edited by
Kare Larsson and Stig

E.
Friberg
39.
Seafood: Effects of Technology on Nutrition,
George M, Pigott and
Barbee W. Tucker
40.
Handbook of Vitamins: Second Edition, Revised and Expanded,
edited by Lawrence J. Machlin
41. Handbook
of
Cereal Science and Technology,
Klaus
J.
Lorenz and
Karel Kulp
42.
Food Processing Operations and Scale-Up,
Kenneth J. Valentas,
Leon Levine, and
J.
Peter Clark
43. Fish Quality Control by Computer Vision,
edited by L.
f.
Pau and R.
Olafsson
44. Volatile Compounds in Foods and Beverages,
edited by Henk Maarse
45. Instrumental Methods for Quality Assurance in Foods,

edited by
Daniel
Y.
C.
Fung and Richard
f.
Matthews
46.
Listeria,
Listeriosis, and Food Safety,
Elliot T. Ryser and Elmer H.
Marth
47. Acesulfame-K,
edited by D. G. Mayer and F. H. Kemper
48. Alternative Sweeteners: Second Edition, Revised and Expanded,
ed-
ited by Lyn O'Brien Nabors and Robert C. Gelardi
49.
Food
Extrusion Science and Technology,
edited by Jozef L. Kokini,
Chi-Tang Ho, and Mukund
V.
Kanve
50.
Surimi Technology,
edifed by Tyre
C.
Lanier and Chong M. Lee
51. Handbook of Food Engineering,

edited by Dennis R. Heldman and
Daryl
6.
Lund
52. Food Analysis by HPLC,
edited by Leo M. L. Nollet
53. Fatty Acids in Foods and Their Health Implications,
edited by Ching
Kuang Chow
54.
Clostridium botulinum:
Ecology and Control in Foods,
edited by
Andreas H. W. Hauschild and Karen L. Dodds
55.
Cereals in Breadmaking: A Molecular Colloidal Approach,
Ann-Charlotte Eliasson and Kire Larsson
56.
Low-Calorie Foods Handbook,
edited by Aaron
M.
Alfschul
57.
Antimicrobials in Foods: Second Edition, Revised and Expanded,
edited by
P.
Michael Davidson and Alfred Larry Branen
58. Lactic Acid Bacteria,
edited by Seppo Salminen and Atte
von

Wright
59. Rice Science and Technology,
edited by Wayne E, Marshall and
James 1. Wadsworth
60.
Food Biosensor Analysis,
edited by Gabriele Wagner and George G.
Guilbault
61. Principles of Enzymology for the Food Sciences: Second Edition,
John
R. Whifaker
62. Carbohydrate Polyesters as Fat Substitutes,
edifed by Casimir C.
Akoh and Barry G. Swanson
63. Engineering Properties of Foods: Second Edition, Revised and
Expanded,
edited by M.
A.
Rao and
S.
S.
H. Rizvi
64. Handbook of Brewing,
edited
by
William A. Hardwick
65. Analyzing Food for Nutrition Labeling and Hazardous Contaminants,
edited
by
Ike J. Jeon and William G. lkins

66. Ingredient Interactions: Effects on Food Quality,
edited
by
Anilkumar
G. Gaonkar
67. Food Polysaccharides and Their Applications,
edited
by
Alisfair
M.
Stephen
68. Safety of Irradiated Foods: Second Edition, Revised and Expanded,
J.
F.
Diehl
69. Nutrition Labeling Handbook,
edited
by
Ralph Shapiro
70. Handbook of Fruit Science and Technology: Production, Composition,
Storage, and Processing,
edited
by
D. K. Salunkhe and
S.
S.
Kadam
71.
Food Antioxidants: Technological, Toxicological, and Health Perspec-
tives,

edited
by
0.
L. Madhavi,
S.
S.
Deshpande, and
D.
K. Salunkhe
72. Freezing Effects on Food Quality,
edited
by
Lester
E.
Jeremiah
73. Handbook
of
Indigenous Fermented Foods: Second Edition, Revised
and Expanded,
edited
by
Keith
H.
Steinkraus
74. Carbohydrates in Food,
edited
by
Ann-Charlotte Eliasson
75. Baked Goods Freshness: Technology, Evaluation, and Inhibition of
Staling,

edited
by
Ronald
E.
Hebeda and Henry
F.
Zobel
76. Food Chemistry: Third Edition,
edited
by
Owen
R. Fennema
77. Handbook
of
Food Analysis: Volumes
1
and 2,
edited
by
Leo M. L.
Nollet
78. Computerized Control Systems in the Food Industry,
edited
by
Gauri
S.
Mittal
79. Techniques for Analyzing Food Aroma,
edited
by

Ray Marsili
80. Food Proteins and Their Applications,
edited
by
Srinivasan Darno-
daran and Alain Paraf
81. Food Emulsions: Third Edition, Revised and Expanded,
edited
by
Sfig
E.
Friberg
and Kire Larsson
82. Nonthermal Preservation
of
Foods,
Gusfavo
V.
Barbosa-Cdnovas,
Usha R. Pothakamury, Enrique Palou, and Barry G. Swanson
83. Milk and Dairy Product Technology,
Edgar Spreer
84. Applied Dairy Microbiology,
edited
by
Elmer H. Marth and James L.
Steele
85. Lactic Acid Bacteria: Microbiology and Functional Aspects: Second
Edition, Revised and Expanded,
edited

by
Seppo Salminen and Atfe
von Wright
86. Handbook of Vegetable Science and Technology: Production,
Composition, Storage, and Processing,
edited
by
D. K. Salunkhe and
S.
S.
Kadam
87. Polysaccharide Association Structures in Food,
edited
by
Reginald H.
Walter
88. Food Lipids: Chemistry, Nutrition, and Biotechnology,
edited
by
Casimir C. Akoh and David
6.
Min
89. Spice Science and Technology,
Kenji Hirasa and Mitsuo Takemasa
90. Dairy Technology: Principles of Milk Properties and Processes,
P.
Walstra,
T.
J. Geurts,
A.

Noomen, A. Jellema, and M.
A.
J.
S.
van
Boekel
91. Coloring of Food, Drugs, and Cosmetics,
Gisbert Offerstaffer
92.
Listeria,
Listeriosis, and Food Safety: Second Edition, Revised and
Expanded,
edited by Elliot
T.
Ryser and Elmer H. Marth
93. Complex Carbohydrates in Foods,
edited by Susan Sungsoo Cho,
Leon Prosky, and Mark Dreher
94. Handbook of Food Preservation,
edited by M. Shafiur Rahman
95. International Food Safety Handbook: Science, International Regula-
tion, and Control,
edited by Kees van der Heijden, Maged Younes,
Lawrence Fishbein, and Sanford Miller
96. Fatty Acids in Foods and Their Health Implications: Second Edition,
Revised and Expanded,
edited by Ching Kuang Chow
97. Seafood Enzymes: Utilization and Influence on Postharvest Seafood
Quality,
edited by Norman

F.
Haard and Benjamin K. Simpson
98. Safe Handling of Foods,
edited by Jeffrey M. Farber and Ewen C.
D.
Todd
99. Handbook of Cereal Science and Technology: Second Edition, Re-
vised and Expanded,
edited by Karel Kulp and Joseph G. Ponte, Jr.
100.
Food Analysis by HPLC: Second Edition, Revised and Expanded,
edited by Leo M. L. Nollet
101. Surimi and Surimi Seafood,
edited by Jae W. Park
102. Drug Residues in Foods: Pharmacology, Food Safety, and Analysis,
Nickos A. Botsoglou and Dimitrios J. Fletouris
103. Seafood and Freshwater Toxins: Pharmacology, Physiology, and
Detection,
edited by Luis
M.
Botana
104. Handbook of Nutrition and Diet,
Babasaheb B. Desai
105. Nondestructive Food Evaluation: Techniques to Analyze Properties
and Quality,
edited by Sundaram Gunasekamn
106. Green Tea: Health Benefits and Applications,
Yukihiko Hara
107. Food Processing Operations Modeling: Design and Analysis,
edited

by Joseph lmdayaraj
108. Wine Microbiology: Science and Technology,
Claudio Delfini and
Joseph V. Formica
109. Handbook of Microwave Technology for Food Applications,
edited by
Ashim K. Daffa and Ramaswamy C. Anantheswaran
110. Applied Dairy Microbiology: Second Edition, Revised and Expanded,
edited by Elmer H. Marfh and James L. Steele
I1 1. Transport Properties of Foods,
George
D.
Saravacos and Zacharias
B.
Maroulis
1 12. Alternative Sweeteners: Third Edition, Revised and Expanded,
edited
by Lyn O’Brien Nabors
113. Handbook of Dietary Fiber,
edited by Susan Sungsoo Cho and Mark
L. Dreher
114. Control of Foodborne Microorganisms,
edited by Vqay K. Juneja and
John N. Sofos
11
5.
Flavor, Fragrance, and Odor Analysis,
edited by Ray Marsili
11 6. Food Additives: Second Edition, Revised and Expanded,
edited by A.

Larry Branen, P. Michael Davidson, Seppo Salminen, and John
H.
Thorngafe,
111
1 17. Food Lipids: Chemistry, Nutrition, and Biotechnology: Second Edition,
Revised and Expanded,
edited by Casimir C. Akoh and David B. Min
118.
Food Protein Analysis: Quantitative Effects on Processing,
R.
K.
Owusu-Apenfen
119. Handbook
of
Food Toxicology,
S.
S.
Deshpande
120. Food Plant Sanitation,
edifed by
Y.
H.
Hui,
Bernard L. Bruinsma, J.
Richard Gorham, Wai-Kit Nip, Phillip
S.
Tong, and Phil Venfresca
121. Physical Chemistry
of
Foods,

Pieter Walsfra
122. Handbook
of
Food Enzymology,
edited by John
R.
Whitaker, Alphons
G.
J.
Voragen, and Dominic W.
S.
Wong
123. Postharvest Physiology and Pathology of Vegetables: Second Edition,
Revised and Expanded,
edited by Jerry A. Bartz and Jeffrey K. Brechf
124. Characterization of Cereals and Flours: Properties, Analysis, and Ap-
plications,
edited by Gonul Kalefunc; and Kenneth J. Breslauer
125. International Handbook
of
Foodborne Pathogens,
edifed by Marianne
D.
Miliotis and Jeffrey W. Bier
126. Food Process Design,
Zacharias B. Maroulis and George
D.
Sara-
vacos
127. Handbook of Dough Fermentations,

edited by Karel Kulp and Klaus
Lorenz
128. Extraction Optimization in Food Engineering,
edited by Consfanfina
Tzia and George Liadakis
129. Physical Principles
of
Food Preservation: Second Edition, Revised
and Expanded,
Marcus Karel and Daryl B. Lund
Additional Volumes
in
Preparation
Handbook
of
Vegetable Preservation and Processing,
edited by
Y.
H.
Hui,
Sue Ghazala, Dee M. Graham, K.
D.
Murrell, and Wai-Kit Nip
Food Emulsions: Fourth Edition, Revised and Expanded,
edited by
Sfig
E.
Friberg, K6re Larsson, and Johan Sjoblom
Handbook
of

Frozen Foods,
edited by
Y.
H. Hui, Paul Cornillon, Isabel
Guerrero Legarrefa, Miang Lim, K.
0.
Murrell, and Wai-Kit Nip
Handbook
of
Food and Beverage Fermentation Technology,
edited by
Y.
H.
Hui,
Lisbeth M. Goddik, Aase Solvejg Hansen, Jytte Josephsen,
Wai-Kit Nip, Peggy
S.
Sfanfield, and Fidel Toldra
Industrialization
of
Indigenous Fermented Foods,
edited by Keith H.
Steinkra
us
To the many undergraduate, graduate, and postdoctoral
students who studied and worked with us over the past four decades. Most
of the ideas and concepts underlying this book were forged in our
interactions with these talented and productive young women and men.

Foreword

Physical Principles of Food Preservation, by Marcus Karel, Owen Fennema, and
Daryl Lund, was first published in 1975 and served as a popular textbook far
longer than is typical, apparently because a suitable replacement was not
available. Preparation of a new edition has been contemplated since about 1985,
but impediments of various kinds precluded its completion. Marcus Karel and
Daryl Lund have finally overcome these obstacles and have given birth to the
second edition. This was not easily accomplished, but the product is one of
considerable significance because the topic is important and the approach taken is
highly suitable for the intended audience—majors in food science and practici ng
food scientists and technologists. The topic of this book was important in 1975
but has become much more so today because of increasing population and the
pressing need for sustainable processing procedures, of little concern in 1975.
Sustainable processing procedures are absolutely necessary if we are to leave our
descendants with access to an adequate supply of safe and nutritious food, clean
air, potable water, fertile soil, and adequate natural resources. The authors have
recognized these needs and addressed them well—a very formidable task.
Appropriateness of the approach is also of great importance. Students
majoring in food science as well as practicing food scientists and technologists
are typically well founded in chemistry, physics, mathematics, biology, and
microbiology but are less skilled in engineering. This fact must be fully
v
recognized if a book for these readers is to be effective. The authors, in my view,
have successfully met this challenge.
After more than a quarter of a century, one expects many changes in a book
of this kind, and they have been incorporated. The book is structured differently,
all of the information has been updated, a vast amount of new information has
been added (e.g., a new chapter on nonthermal processes), and the approach is
appropriately more quantitative, often with a different emphasis than before.
Thus, the book is quite different from the first edition, except for constancy in
purpose and in most of the topics covered.

It is an honor and genuine pleasure to introduce the reader to this fine
second edition of Physical Principles of Food Preservation. I believe you will
find it of great valu e.
Owen Fennema
Department of Food Science
University of Wisconsin –Madison
Madison, Wisconsin, U.S.A.
Forewordvi
Preface to the Second Edition
In the 28 years since the first edition of this textbook, significant advances have
been made in our understanding of physical chemistry of foods, and in particular
of the effects of environmental factors on rates of changes in foods. These
advances in knowledge have led to refinements in formulation of principles of
food p reservation and in the development and application of new processes for
preservation of foods. As predicted in the preface of the first edition, processes
today seek optimization of nutritional and quality factors (such as nutrients,
biologically active ingredients, taste, flavor, color, and texture), energy
utilization, waste generation, and cost.
Advances in knowledge also resulted in descriptions of physical methods
of food preservation, which are based on theoretical principles and are
increasingly quantitative. The contents of this textbook reflect the emphasis on
qualitatively and quantitatively formulating the principles of food preservation
and of storage stability.
Quantitative description is aided by providing the reader with fundamental
physical chemistry and engineering chapters (Chapters 1– 5) on thermodynamics,
kinetics, heat transfer, mass transfer, and water activity. These chapters are
intended to introduce fundamental concepts and rely on the reader’s background
in mathematics, chemistry, and physics. Subsequent chapters (Chapters 6– 11)
are devoted to specific processes for food preservation. They include processes
vii

currently in use, as well as those i n advanced stages of development, including
heat processes, chilling, freezing, concentration processes, dehydration, and
nonthermal proce sses including irradiation. To achieve their objective of food
stabilization, preservation processes must include protective packaging, a subject
that is covered in the last chapter.
This textbook is intended for students in a food science undergraduate
program in which they are introdu ced to food processing principles after having
taken courses in calculus, physics, chemis try, and microbiology. Students in a
graduate program in food science who do not have an undergraduate degree in
food science will also find this textbook of benefit in understanding the principles
of food preservation processes. This applies also to stud ents in related fields (e.g.,
chemical and biochemical engineering, chemistry, material science) who wish to
learn about application of their disciplines to food preservation. Finally, it is our
hope that the book finds good use as a general reference text by those in
professions using food science, such as government and industry professionals.
Marcus Karel
Daryl B. Lund
Preface to the Second Editionviii
Preface to the First Edition
The subject of food processing occupies a position of major importance in the
food science curriculum, and this emphasis is likely to continue. Thus it is both
puzzling and reprehensible that a university-level textbook tailored to the needs
of typical students in food science does not exist. In the United States, the two
largest categories of students represented in food processing courses are
(1) upper-level undergraduates in food science and (2) graduate students that are
entering food science from other disciplines. These students generally have solid
backgrounds in chemistry, bacteriology, biology, mathematics, and physics and
minimal backgrounds in engineering. This book on Physical Principles of Food
Preservation is intended primarily for these students, and secondarily for persons
in the food industr y and for scientists in food-related groups of the government.

In the past, knowled ge of food preservation has been used to develop new
or improved products or more economical (labor-saving) processes. In the future,
knowledge of food preservation techniques will no doubt be applied increasingly
to matters of a more critical nature, i.e., to reducing wastage of the World’s
food supply and to devising processes that optimize the factors of cost,
nutritional quality, environmental impact, and consumption of resources and
energy.
In this book, a qualitative and semiquantitative approach is used, and stress
is given to long-enduring principles rather than to detail. This approach is
ix
necessary if one is to adapt successfully to the changing objectives of food
preservation, as discussed above.
In the introductory chapter, attention is drawn to the fact that food wastage
is a major problem on a world-wide basis, that much of this wastage can be
prevented by proper application of food-preservation techniques, and that
processing advances must be accomplished with due consideration given to the
amounts of energy and resources consumed and to the environmental effects. The
remainder of the book is divided into four sections: the first deals with
preservation by means of temporary increases in the product’s energy content
(heat processing, irradiation); the second deals with preservation by controlled
reduction of the product’s temperature (chilling, freezing); the third deals with
preservation by controlled reduction of the product’s water content (concen-
tration, air—dehydration, freeze—drying); and the last deals with packaging—an
important means of protecting foods during storage. Chapters are also included at
appropriate places to familiarize the reader with the principles of phase
equilibria, heat transfer, mass transfer, and water activity.
It is hoped that this book shall enlighten readers with respect to the
principles of physical methods of food preservation and thereby encourage use of
methods that are most suitable to the needs of society.
Marcus Karel

Owen Fennema
Daryl B. Lund
Preface to the First Editionx
Acknowledgments
We have been encouraged to produce the second edition of this popular textbook
for at least the past 15 years. To the professors, instructors, colleagues, friends,
and students who provided this encouragement, we express our deep appreciation
for their confidence in our ability to contribute to the teaching of food science
principles. Our production editor, Theresa Dominick Stockton, and acquisitions
editor, Maria Allegra, were sources of constant encouragement. We would be
remiss, however, if we did not acknowledge the special encourage ment and
support we received from our respective wives, Cal and Dawn, and from the
original series editor, Owen Fennema. Thank you one and all.
xi

Contents
Foreword v
Preface to the Second Edition vii
Preface to the First Edition ix
PART I. PRINCIPLES
1. Thermodynamics 1
I. Introduction 1
II. Thermodynamic Fundamentals 1
A. Definition of Systems 2
B. First Law of Thermodynamics 2
C. Second Law of Thermodynamics 5
D. Thermodynamic Potential: Gibbs Free Energy 6
III. Solution Properties 9
A. Partial Molar Qua ntities 9
B. Chemical Potential 10

C. Ideal Mixtures 11
D. Nonideal Mixtures 14
IV. Phase Equilibria 15
xiii
A. Liquid–Vapor Equilibria 17
B. Solid–Liquid Equilibria 18
C. Solid–Vapor Equilibria 18
D. Phase Rule 19
E. Pressure-Compositi on Diagram 20
V. Colligative Properties 22
A. Vapor Pressure Lo wering 23
B. Boiling Point Elevation 23
C. Freezing Point Dep ression 24
D. Osmotic Pressure 25
Symbols 26
References 27
2. Reaction Kinetics 28
I. Introduction 28
II. General Considerations 29
A. Concept of Rate-Limiting Step 29
B. Basic Chemical Kinetics 30
C. Order of Reaction 31
III. First-Order Rate Processes 32
IV. Determining Kinetic Parameters 35
A. General Considerati ons 35
B. Differential Methods 38
C. Integral Methods 39
D. Accuracy of Rate Constants 40
V. Temperature Dependence of Reaction Kinetics 41
A. Arrhenius Model 41

B. Thermal Death Time Model 42
C. Q
10
Model 42
VI. Kinetic Parameter Values Important in Food
Processing 43
VII. Enzyme-Catalyzed Reactions 45
A. Introduction 45
B. Michaelis–Menten Analysis 45
VIII. Summary 48
References 49
3. Heat Transfer in Food 50
I. Introduction 50
II. Mechanisms of Heat Transfer 51
A. Conduction 58
B. Convection 60
Contentsxiv
C. Radiation 65
D. Dielectric and Mic rowave Heating 68
III. Steady-State Heat Transfer 70
A. Conduction Heat Transfer in Series 70
B. Convection Heat Transfer Coefficient 73
C. Free or Natural Convection 74
D. Forced Convection 75
IV. Unsteady-State Heat Transfer 76
A. General Principles 76
B. Unaccomplished Temperature Change 80
C. Generalized Solution for Unsteady-State Heat
Transfer 81
D. Negligible Internal Resistance to Heat Transfer

(Well-Mixed Fluid) (Bi , 0.1) 82
E. Finite Internal Resis tance to Heat Transfer
(Bi . 0.1) 83
F. Example 87
G. Finite Objects 89
H. Other Conditions 90
Symbols 90
References 91
4. Mass Transfer in Food Preservation Processes 92
I. Introduction 92
II. Phase Equilibria 93
A. The Phase Rule 93
B. Gas–Liquid Equilibria 93
C. Solutions 95
D. Representation of Eq uilibrium Relationships for Binary
Systems with Two Volatile Components 95
E. Colligative Properties Related to Vapor Pressure 97
F. Liquid–Liquid Equilibria 98
G. Gas–Solid Equilibria 99
III. Mass Transfer Between Phases 101
A. Interface Between Phases 101
B. Diffusion Within a Homogeneous Phase 102
C. Nonideal Diffusion Behavior 108
D. Film Coefficients for Mass Transfer 111
E. Transport in Porous Solids 113
F. Simultaneous Heat and Mass Transfer 114
Symbols 114
References 115
Contents xv
5. Water Activity and Food Preservation 117

I. Introduction 117
II. Water Activity 118
III. Sorption of Water by Foods 120
IV. Indicators of the State of Water in Foods 124
V. Causes of Water Vapor Depression in Foods 126
VI. Sorption Hysteresis 130
VII. Water Activity of Mixtures 134
VIII. Water and Glass Transitions in Food Materials 136
IX. Overview of Effects of Water Activity on Shelf
Life of Foods 142
X. Water Activity and Physical Changes in Foods 143
XI. Effects of Water on Microbial Growth 152
XII. Water and Chemical Reactions in Foods 156
Symbols 166
References 167
PART II. PRESERVATION PROCESSES
6. Heat Processing 170
I. Introduction 170
II. Application of Heat Energy to Foods 170
A. Cooking 171
B. Blanching 171
C. Pasteurization 173
D. Sterilization 174
III. Interaction of Heat Energy and Food Components 178
A. Introduction 178
B. Reaction Kinetics 179
C. Temperature Dependence on Kinetics 180
D. Thermal Destruction of Microorganisms 184
E. Thermal Destruction of Enzymes 191
F. Thermal Destruction of Nutrients and Quality Factors 192

IV. Heat Penetration into Foods 197
A. Introduction 197
B. Determination of Time –Temperature Profile for
Thermal Process Calculations 198
C. Evaluation of Hea t Penetration Data 199
V. Methods of Determining Lethality of Thermal Processes 203
A. Introduction 203
B. Improved General Method 204
Contentsxvi
C. Formula Method 207
D. Aseptic Processing 214
VI. Process Application 219
A. Optimization of Thermal Processes for Nutrient
Retention 220
B. Process Equipment 223
Symbols 233
References 234
7. Storage at Chilling Temperatures 237
I. Introduction 237
II. Considerations 238
A. Normal Behavior of Food Stored at Chilling
Temperatures 238
B. Causes of Quality Loss 242
C. Temperature 244
D. Relative Humidity 252
E. Air Circulation and Purification 252
F. Adjuncts to Chilling Temperature 252
G. Summary of Product Characteristics That Influence
Conditions Selected for Chilling Storage 259
III. Applications and Proce dures 259

A. Precooling 259
B. Conditions Recommended for Storage of Food in
Ordinary Air at Chilling Temperatures 261
C. Conditions Recommended for Storage of Food in
Chilled Atmospheres of Modified Composition 263
D. Handling of Food Follow i ng Removal from Chilling
Storage 273
References 273
8. Freezing 276
I. Introduction 276
A. Objectives of Freezing of Foods 276
B. Size of the Food Industry 277
II. Physicochemical Principles of the Freezing
Process 277
A. Introduction 277
B. Water and Ice 278
C. Nucleation in Pure Water 283
D. Freezing Point Depression in Solutions, Biological
Systems, and Foods 287
Contents xvii
E. Crystal Growth 292
F. Recrystallization 293
III. Glassy State and Preservation by Freezing 297
IV. Biological Aspects of Freezing 300
A. Cryopreservation of Cells and Other Biomaterials 300
B. Biological Ice Nucleation 304
C. Antifreeze Proteins 305
V. Freezing Technology 307
A. Air Freezers 308
B. Indirect Contact Freezers 309

C. Immersion Freezing 311
D. Cryogenic Freezing 311
E. High Pressure Applications in Freezing Technology 312
VI. Design Calculations 314
A. Heat to Be Removed 315
B. Calculation of Freezing Time 315
C. Illustrative Example s 317
VII. Effects of Freezing, Storage, and Thawing on Food
Properties 322
A. Effects of Freezing 323
B. Effects of Storage in the Frozen State 324
C. Effects of Thawing 326
Symbols 327
References 327
9. Concentration 330
I. Introduction 330
II. Evaporation 331
A. Principles of Evapor ator Operation 331
B. Boiling Point Estimation 333
C. Food Properties and Evaporator Performance 334
D. Types of Evaporators 337
E. Evaporation with Feed Preheating 342
F. Multiple-Effect Evaporators 343
G. Evaporators with Vapor Recompression 345
H. Principles of Operation of Equipment Used in
Evaporators 349
I. Examples of Evaporator Systems in Industry 354
III. Freeze Concentration 355
A. Introduction 355
B. Principle of the Process 355

C. Freeze Concentra tion and Freeze Desalination 358
Contentsxviii