FOOD POLYMER SCIENCE:
APPLICATIONS IN INGREDIENT FUNCTIONALITY AND BAKING TECHNOLOGY
______________________________________________________________
COURSE MANUAL
_____________
TABLE OF CONTENTS
_________________
Course Description.........................................................
Course Outline and Lecture Schedule........................................
Faculty Biographies........................................................
Moisture Management in Foods - Integrating Theory and Practice.............
Bakery Ingredients and Products at Low Moisture Contents
- Water as Plasticizer...................................................
Structural Stability of Intermediate Moisture Foods, Including Baked
Goods - A New Understanding Beyond Water Activity........................
Cryostabilization Technology - The Thermomechanical Stabilization of
Frozen Products..........................................................
Aspects of Starch as a Partially Crystalline, Water-Compatible Polymer
that is a Major Constituent of Baked Goods...............................
Polymer Physicochemical Properties of Gluten and Other Proteins in
Baked Goods..............................................................
Food Polymer Science Approach to Ingredient Functionality in Cookie/
Cracker Baking Technology................................................
Examples of Applications of Greatest Interest to Participants..............
Course Reading List and Bibliography.......................................
GLOSSARY of Symbols and Abbreviations......................................
(H13-2)

FOOD POLYMER SCIENCE:
APPLICATIONS IN INGREDIENT FUNCTIONALITY AND BAKING TECHNOLOGY
A Four-Day Intensive Course
COURSE DESCRIPTION
Water, the most abundant constituent of natural foods, is a ubiquitous plasti- cizer of most natural and fabricated food ingredients and products. Many of the new concepts and developments in modern food science and technology revolve around critical aspects of the role of water, and its manipulation, in food manufacturing, processing, and preservation. This course will describe the ef- fects of water, as a near-universal solvent and plasticizer, on the diffusion- limited behavior of polymeric (as well as oligomeric and monomeric) food mater- ials and systems, with emphasis on the impact of water content (in terms of in- creasing system mobility and eventual water "availability") on food quality, safety, stability, and technological performance. Participants will be exposed to a new perspective on moisture management, an old and established discipline now evolving to a theoretical basis of fundamental structure-property princi- ples from the field of synthetic polymer science, including the innovative con- cepts of "water dynamics" and "glass dynamics". These integrated concepts focus on the non-equilibrium nature of all "real world" food products and processes, and stress the importance to successful moisture management of the maintenance of food systems in kinetically-metastable, dynamically-constrained states rath- er than equilibrium thermodynamic phases. The understanding derived from this
"food polymer science" approach to water relationships in foods has led to new insights and recent advances beyond the limited applicability of traditional concepts involving "water activity". Unlike conventional courses on "water ac- tivity", this course has been designed to provide participants with up-to-date, usable information on moisture management theory, research, and practice appli- cable to water relationships in food systems which cover the broadest ranges of moisture content and processing/storage temperature conditions.
FOR WHOM INTENDED
This course is intended for a broad spectrum of industry professionals, from R&D personnel (including basic and applied scientists, technologists, process engineers, and technical managers) to individuals involved in manufacturing and production, plant processing, packaging, preservation, quality control and assurance, and technical sales.
[H26-9]

Short Course
FOOD POLYMER SCIENCE:
APPLICATIONS IN INGREDIENT FUNCTIONALITY AND BAKING TECHNOLOGY
-------------------------------------------------------------------------------
COURSE OUTLINE AND LECTURE SCHEDULE
===================================
Session I (120 minutes), Part A (Slade): MOISTURE MANAGEMENT IN FOODS -
INTEGRATING THEORY AND PRACTICE
* Physicochemical Properties of Water in Foods
* Properties of Water in its Liquid and Solid States
* Properties of Solutions
* Interactions of Water with Food Components
* Sorption of Water by Food Materials
* Introductory Concepts, Approaches, and Principles of Food Polymer Science
Break (15 min)
Session I (120 min), Part B (Slade)
* Structure-Property Relationships of Food Polymers, Oligomers, and Monomers
* Water Dynamics and Glass Dynamics - Innovative Perspectives on Kinetically
Controlled Behavior of Concentrated Food Systems; Water as Plasticizer;
Mobility
* Dynamics Map/State Diagrams - "The Real (Non-Equilibrium) World" of Food
Products During Processing and Storage; Effects of Moisture Content,
Temperature, Time
Session II (120 min), Part A (Levine): BAKERY INGREDIENTS AND PRODUCTS AT LOW
MOISTURE CONTENTS - WATER AS PLASTICIZER
* Low Moisture Technology of Amorphous and Partially Crystalline Food Polymers
* Water as a Ubiquitous Solvent and Plasticizer of Food Materials, including
Bakery Ingredients and Products
* "Collapse" Phenomena - A Unifying Concept for Interpreting and Predicting
Functional Behavior of Food Powders, Candy Glasses, and Frozen Products
such as Frozen Doughs
Break (15 min)
Session II (120 min), Part B (Levine)
* Thermomechanical Properties and Non-Equilibrium Behavior of Low Molecular
Weight Carbohydrate-Water Glasses and Rubbers - The Glass Transition
* A Polymer Physicochemical Approach to Characterizing Structure-Function
Relationships of Commercial Starch Hydrolysis Products
Session III (120 min), Part A (Slade): STRUCTURAL STABILITY OF INTERMEDIATE
MOISTURE FOODS, INCLUDING BAKED GOODS -
A NEW UNDERSTANDING BEYOND WATER ACTIVITY
* Applications of Food Polymer Science Concepts, Approaches, and Principles
* "Water Activity" and Microbial Stability
* "Water Activity" as a Measure of Biological Viability and Quality Control
* Beyond "Water Activity": Recent Advances in the Assessment of Food Safety,
Quality, Stability, and Technological Performance
Break (15 min)
Session III (120 min), Part B (Slade)
* Moisture Management in Intermediate Moisture Foods such as Baked Goods
* Moisture Management Technology - Modern Insights and Interpretations
* Principles of Stabilization of IMFs
* Problems Arising from Non-Homogeneous Distribution of Water

* Effects of Water Content on Diffusion in Foods
* Glass Transitions, Crystallization, and Effects on Diffusion
Session IV (120 min), Part A (Levine): CRYOSTABILIZATION TECHNOLOGY - THE
THERMOMECHANICAL STABILIZATION OF FROZEN PRODUCTS
* Cryostabilization Technology - the Thermomechanical Stability of Frozen Foods
such as Frozen Dough Products
* Cryostabilization of Frozen Foods - Stability vs. Mobility
* Cryoprotection of Freezer-Stored Foods - Criticality of "Unfreezable" Water
Break (15 min)
Session IV (120 min), Part B (Levine)
* "Bound Water" and "Water-Binding Capacity" - Dispelling the Myths
* Methodology for Studying Mobility (rather than "Binding") of Water
* Cryostabilization Technology for Real Food Systems
Session V (120 min), Part A (Slade): ASPECTS OF STARCH AS A PARTIALLY
CRYSTALLINE, WATER-COMPATIBLE POLYMER
THAT IS A MAJOR CONSTITUENT OF BAKED GOODS
* Thermomechanical Properties of Native and Gelatinized Starches
* Starch Properties in Processed Foods - Staling of Starch-Based Products
Break (15 min)
Session V (120 min), Part B (Slade)
* Recent Advances in Starch Retrogradation - Staling Technology
* Starch Recrystallization as a Moisture Management Problem - Mechanism
Session VI (120 min), Part A (Levine): POLYMER PHYSICOCHEMICAL PROPERTIES OF
GLUTEN AND OTHER PROTEINS IN BAKED GOODS
* Gluten as an Amorphous, Viscoelastic Food Polymer System
* Gluten Functionality in Baked Goods - Thermosetting vs. Thermoplastic
Behavior
Break (15 min)
Session VI (120 min), Part B (Levine)
* The Baking Mechanism of Sugar-Snap and Wire-Cut Cookies - Time-Lapse Photo-
graphic Analyses, Structure-Function Relationships of Flours and Sucrose,
Flour Functionality, Effects of Sucrose
* Polymer Physicochemical Properties of Gelatin and Other Food Proteins
Session VII (120 min), Part A: FOOD POLYMER SCIENCE APPROACH TO INGREDIENT
(Slade/Levine) FUNCTIONALITY IN COOKIE/CRACKER BAKING TECHNOLOGY
* Advanced Cookie Baking Science - Variations on AACC Cookie Method 10-53
* Effects of Sucrose, Water, Leavening Agents, and Enzymes on Cookie Baking
* Cookie Color Development and Stability
Break (15 min)
Session VII (120 min), Part B (Levine/Slade)
* Cookie and Cracker Flours - Quality and Functionality
* Diagnostic DSC and Alveography

Session VIII (120 min), Part A (Levine/Slade): EXAMPLES OF APPLICATIONS OF
GREATEST INTEREST TO PARTICIPANTS
* Participant Contributions
* Review of Application Examples
* Review of Case Studies
Break (15 min)
Session VIII (120 min), Part B (Levine/Slade)
* How to Capitalize on Food Polymer Science Approach in Industrial R&D Labs
* Discussion, Next Steps, and Follow-Up
End
-----------------------------------------------------------------------------
[H26-9a revised 1/24/09]

LOUISE SLADE & HARRY LEVINE -- BIOGRAPHIES/VITAE
– MAY 2009
Dr. Louise Slade heads her own consulting business, Food Polymer Science Consultancy. Dr. Slade retired in 2006 as a Kraft Foods
Fellow in Nabisco Biscuit & Snacks R&D of Kraft Foods. Prior to Kraft's acquisition of Nabisco in late 2000, Dr. Slade had been a
Nabisco Research Fellow since 1997, after having become Nabisco's first Research Fellow (Fundamental Science Group) in 1990. She was, until 1987, a Research Scientist in the Central Research Dept. of General Foods. Dr. Slade joined GF in 1979 after 5 years at the
University of Illinois in the lab of Dr. Gregorio Weber as an NIH Postdoctoral Fellow in biochemistry. Since 1980, Dr. Slade, in partnership with Dr. Harry Levine, has developed an innovative research program in Food Polymer Science. In 1999, Drs. Slade and
Levine received the IFT Industrial Scientist Award for their major technical contributions to the advancement of the food industry. In
2004, Drs. Slade and Levine were honored with the prestigious Tanner Award from IFT's Chicago Section. In 2007, Drs. Slade and
Levine received the Halverson Award from the Milling and Baking Division of AACC International. And in 2008, Drs. Slade and Levine were honored with AACCI’s prestigious Applied Research Award. Dr. Slade has 28 U.S. patents (the majority of which have been industrially commercialized) for novel food products and processes, including two for soft-from-the-freezer ice creams. For her research contribution to that development effort, Dr. Slade was awarded GF's coveted Chairman's Award in 1986. She was also awarded
Nabisco's prestigious FIAT Award in 1989 for her outstanding technical contributions to Nabisco's Biscuit Company, and in 2001, she became the first Nabisco scientist to win Kraft's Technology Leadership Award. Since 1982, she and Dr. Levine have jointly published and/or presented internationally over 225 papers in the areas of food polymer science, starch and cereal grain science and technology, cryostabilization technology, baking science, and water relationships in foods. These papers have been cited over 5550 times in publications by other workers. Dr. Slade has been honored, for her leadership in the polymer science approach to research on food carbohydrates, by an invitation to present the 1987 Belfort Memorial Lecture at the Whistler Carbohydrate Research Center at Purdue
University. In 2004, Dr. Slade was remarkably honored by having a new wheat cultivar named "Louise" after her, by the wheat's breeder. "Louise" is a high-quality, biscuit-friendly, Washington Soft White Spring wheat, whose breeding development was guided by new flour quality testing methodology that Dr. Slade had created at Nabisco in 1988, and which was adopted by the American
Association of Cereal Chemists (AACC) as Official Method #56-11 in 1999. Drs. Slade and Levine developed a short course on Food
Polymer Science, which they have presented 28 times since 1987, to nearly 800 attendees in the US, Europe, Australia and Asia, under the sponsorship of six different professional organizations. This partnership has also edited a book on Water Relationships in
Foods (Plenum, 1991), developed from an international symposium they organized for the American Chemical Society, and has guestedited a special issue for the Journal of Thermal Analysis on the Thermal Analysis of Foods (1996). Dr. Slade is a Fellow of AACCI, has been a member of IFT, American Chemical Society, AAAS, Society of Biomolecular Sciences, NY Academy of Sciences, and Phi Beta
Kappa, and has served on the Editorial Board of Carbohydrate Polymers journal and on the International Advisory Committee of
ISOPOW. She received her PhD in chemistry from Columbia University, NY in 1974 and her BA in Biology from Barnard College, NY in
1968. Most recently in 2008, Dr. Slade was honored with an appointment as an Affiliated Scientist at the Monell Chemical Senses
Center in Philadelphia.
Dr. Harry Levine is an associate of Food Polymer Science Consultancy, Dr. Louise Slade's consulting business. Dr. Levine retired in
2006 as a Kraft Foods Fellow in Nabisco Biscuit & Snacks R&D of Kraft Foods. Prior to Kraft's acquisition of Nabisco in late 2000, Dr.
Levine had been a Nabisco Research Fellow since 1997, after having been promoted in 1991 to Research Fellow in the Fundamental
Science Group of Nabisco. He was, until 1987, a Research Scientist in the Central Research Dept. of General Foods. Dr. Levine joined
GF in 1976 as a Sr. Polymer Chemist, after 2 years of post-doctoral research on polymeric cancer drugs in the Biophysics Dept. of
Roswell Park Memorial Institute in Buffalo, NY. Since 1980, Dr. Levine, in partnership with Dr. Louise Slade, has developed an innovative basic research program and group in the area of Food Polymer Science, a new discipline that emphasizes glass transitions and water plasticization in foods as two of its central themes. In 1999, Drs. Levine and Slade received the IFT Industrial Scientist Award for their major technical contributions to the advancement of the food industry. In 2004, Drs. Levine and Slade were honored with the prestigious Tanner Award from IFT's Chicago Section. In 2007, Drs. Levine and Slade received the Halverson Award from the Milling and Baking Division of AACC International. And in 2008, Drs. Levine and Slade were honored with AACCI’s prestigious Applied
Research Award. Dr. Levine has 30 U.S. patents (the majority of which have been industrially commercialized) for novel food products and processes, including two, from his research on moisture management in frozen foods (cryostabilization technology), for soft-fromthe-freezer ice creams. For his contribution to that development effort, Dr. Levine was awarded GF's coveted Chairman's Award in
1986. And in 2004, Dr. Levine received Kraft's Global Technology Leadership Award. Since 1982, he and Dr. Slade have jointly published and/or presented internationally over 225 papers in the areas of food polymer science, moisture management, water-polymer interactions, cryostabilization technology, and baking science. These papers have been cited over 5550 times in publications by other workers. Drs. Levine and Slade developed a short course on Food Polymer Science, which they have presented 28 times since 1987, to nearly 800 attendees in the US, Europe, Australia and Asia, under the sponsorship of six different professional organizations. This partnership has also edited a book on Water Relationships in Foods (Plenum, 1991), developed from an international symposium they organized for the American Chemical Society, and has guest-edited a special issue of the Journal of Thermal Analysis on the Thermal
Analysis of Foods (1996). Dr. Levine has also edited a book on Amorphous Food and Pharmaceutical Systems (Royal Society Chem.,
2002), developed from an international conference he co-organized for the BioUpdate Foundation. Dr. Levine is a Fellow of AACCI and the American Institute of Chemists, has been a member of American Chemical Society, IFT, Society for Cryobiology, American
Biophysical Society, NY Academy of Sciences, and Sigma Xi, and has served on the Editorial Boards of the journals Cryo-Letters,
Comments on Agricultural & Food Chemistry, and Food Hydrocolloids. He received his PhD in Polymer Chemistry (1975), under Prof.
Fred Billmeyer, and his BS in Chemistry (1968) from Rensselaer Polytechnic Institute in Troy, NY.

MOISTURE MANAGEMENT IN FOODS - INTEGRATING THEORY AND PRACTICE
Louise Slade and Harry Levine
ABSTRACT
A new understanding of the structure/activity relationships of foods and food ingredients can be approached through Food Polymer Science, a new research dis- cipline which emphasizes the fundamental and generic similarities between syn- thetic polymers and food molecules. Through the application of well-establish- ed structural principles from the field of polymer science, the functional pro- perties of food materials during processing and finished-product storage can be explained and often predicted. The purpose of this lecture is to introduce some of the innovative concepts and perspectives of this evolving field, by means of selected topics which illustrate new interpretations and insights available to the modern food scientist. The scope of coverage of this lecture is intended to be illustrative rather than exhaustive or comprehensive, and will include spe- cific subjects described in more detail in subsequent lectures.
The discipline of food polymer science has been developed to unify structural aspects of foods (conceptualized as amorphous or partially-crystalline polymer systems, the latter typically based on the "fringed micelle" structural model) with functional aspects conceptualized in terms of Water Dynamics and Glass
Dynamics. Through this unification, the kinetically-controlled behavior of a concentrated food system may be described by a single map (which is derived from a solute-solvent "state" diagram), in terms of moisture content, tempera- ture, and time. The domains of moisture content and temperature, traditionally described by the concepts of "water activity", "bound water", cryoprotection, and sorption isotherms, can be treated as aspects of Water Dynamics, which can be used to explain the moisture management of Intermediate Moisture Foods or the cryostabilization of frozen, freezer-stored, or freeze-dried foods. Glass
Dynamics focusses on the temperature dependence of the relationships among com- position, structure, thermomechanical properties, and functional behavior, and can be used to describe a unifying concept for understanding "collapse" phenom- ena, which govern, e.g., the caking of food powders. Glass Dynamics is also a useful concept for elucidating the physico-chemical mechanisms of structural changes involved in various melting and (re)crystallization phenomena which are relevant to many partially-crystalline food polymers and processing/storage situations, including, e.g. the gelatinization and retrogradation of starches and the gelation of gelatin.
The critical feature of the dynamic map is the identification of the glass-to
-rubber state transition as the reference surface which serves as a basis for the description of the non-equilibrium behavior of food systems, in response to changes in moisture content, temperature, and time. The kinetics of all diffu- sion-controlled relaxation processes, which are governed by the mobility of the water-plasticized polymer matrix, vary (from Arrhenius to Williams-Landel-Ferry type) between distinct temperature/structural domains, which are divided by this glass transition. The viscoelastic, rubbery fluid state, for which WLF kinetics apply, represents the most significant domain for the study of Water
Dynamics. One particular location on the reference surface, which results from the behavior of water as a crystallizing plasticizer, represents the practical glass with maximum moisture content as a kinetically-metastable, dynamically
-constrained solid which is pivotal to characterization of the structure and function of amorphous and partially crystalline food materials. From the theo- retical basis provided by the integrated concepts of Water Dynamics and Glass
Dynamics, experimental approaches can be suggested for predicting the technolo- gical performance, product quality and stability of many foods. [H13-2b]

BAKERY INGREDIENTS AND PRODUCTS AT LOW MOISTURE CONTENTS - WATER AS PLASTICIZER
Harry Levine and Louise Slade
SUMMARY
A unifying concept for "collapse" phenomena in completely-amorphous or partially-crystalline food materials is described. Collapse phe- nomena are regarded as diffusion-controlled consequences of a struc- tural relaxation which depends on the occurrence of an underlying
"state" transformation at the glass-to-rubber transition temperature
Tg. The effect of plasticization by water (leading to increased mo- bility) on Tg is a central element of the concept and the collapse mechanism derived from it. A general physico-chemical mechanism for collapse is proposed, based on the occurrence of a material-specific structural transition at Tg, followed by viscous flow in the rubbery liquid state. The mechanism is derived from Williams-Landel-Ferry
(WLF) free volume theory for amorphous polymers, and leads to a con- clusion of the fundamental identity of Tg with the transition tempe- ratures observed for structural collapse (Tc) and recrystallization
(Tr). To illustrate our concept of collapse phenomena, the behavior of 80 commercial starch hydrolysis products [SHPs, of dextrose equi- valent (DE) 0.3-100] and 60 other polyhydroxy compounds (sugars, glycosides, and polyhydric alcohols) was studied by a low-temperat- ure Differential Scanning Calorimetry (DSC) technique. The method, based on derivative thermograms, was used to measure Tg', the char- acteristic subzero Tg of a maximally-freeze-concentrated aqueous so- lution. Linear correlations between Tg' and DE for the SHPs and be- tween Tg' and inverse molecular weight (1/MW) for the polyhydroxy compounds have been demonstrated. A plot of Tg' vs. number-average
MW (Mn) illustrates the classical behavior of SHPs as a homologous series of amorphous glucose polymers, and reveals an "entanglement coupling" capability for SHPs of < 6 DE and Tg' > -8 C, which is not evidenced by the lower-MW polyhydroxy compounds. The possible rela- tionship between intermolecular entanglement (leading to network formation) and SHP functionality as a food ingredient in applicat- ions involving gelation, encapsulation, frozen-storage stabilizat- ion, thermomechanical stabilization, or facilitation of drying proc- esses is discussed. The utility of low-DE SHPs for inhibiting vari- ous collapse phenomena, which affect the processing/storage stabili- ty of many foods, is described and explained, as is the contrasting role typically played by sugars and polyols in promoting these phen- omena. An example of the inhibition of enzymatic activity in a fro- zen system, stabilized with low-DE maltodextrin, is also reported.
____________________________________________________________________________
Reproduced, with permission, from Levine, H. & Slade, L. (1987). Collapse
Phenomena - A Unifying Concept for Interpreting the Behavior of Low-Moisture
Foods. In Food Structure - Its Creation and Evaluation, eds. J.R. Mitchell &
J.M.V. Blanshard, Butterworths, London, chapter 9.
[H13-2c]

STRUCTURAL STABILITY OF INTERMEDIATE MOISTURE FOODS, INCLUDING BAKED GOODS -
A NEW UNDERSTANDING BEYOND WATER ACTIVITY
Louise Slade and Harry Levine
ABSTRACT
A new understanding of structural stability of intermediate moisture foods (IMFs) can be approached through food polymer science. This new discipline was developed to unify structural aspects of foods
(conceptualized as completely-amorphous or partially-crystalline po- lymer systems, the latter based on the "fringed micelle" model) with functional aspects of "water dynamics" and "glass dynamics". Through this unification, the kinetically-controlled behavior of a concen- trated food system may be described by a map (derived from a solute
-solvent "state" diagram), in terms of moisture content, temperature
(T), and time. The domains of moisture content and T, traditionally described by concepts of "water activity" (Aw), "bound water", cryo- protection, and sorption isotherms, can be treated as aspects of wa- ter dynamics. Glass dynamics focuses on the T dependence of relati- onships among composition, structure, and functional behavior, and can be used to describe a unifying concept for understanding "col- lapse" phenomena. The critical feature of the dynamic map is identi- fication of the glass-to-rubber state transition as a reference sur- face which serves as a basis for description of non-equilibrium be- havior of food systems, in response to changes in moisture content,
T, and time. Kinetics of all diffusion-controlled relaxation proces- ses, which are governed by mobility of the water-plasticized polymer matrix, vary (from Arrhenius to Williams-Landel-Ferry) between dis- tinctive T/structural domains, which are divided by this glass tran- sition. The viscoelastic, rubbery fluid state, for which WLF kine- tics are pertinent, represents the significant domain for study of water "availability", measurable in terms of a product's relative vapor pressure (RVP). One particular location on the reference surf- ace, which results from behavior of water as a crystallizing plasti- cizer, represents the practical glass with maximum moisture content as a kinetically-metastable, dynamically-constrained solid which is pivotal to characterization of structure/function of amorphous and partially-crystalline food systems. Based on understanding derived from concepts of water dynamics and glass dynamics, an experimental approach is suggested for predicting technological performance, pro- duct quality and stability of IMFs. Examples are described which il- lustrate the increased insight and predictive utility of this ap- proach vs. others traditionally based only on measurements of "Aw".
_______________________________________________________________________________
Reproduced, with permission, from Slade, L. & Levine, H. (1987). Structural
Stability of Intermediate Moisture Foods - A New Understanding? In Food
Structure - Its Creation and Evaluation, eds. J.R. Mitchell & J.M.V. Blanshard,
Butterworths, London, chapter 8.
See also Slade, L. and Levine, H. (1991a). Beyond Water Activity: Recent
Advances Based on an Alternative Approach to the Assessment of Food Quality and
Safety. CRC Crit. Revs. Food Sci. Nutr. 30(2-3): 115-360.
[H13-2d]

CRYOSTABILIZATION TECHNOLOGY - THE THERMOMECHANICAL STABILITY OF FROZEN PRODUCTS
Harry Levine and Louise Slade
SUMMARY
Cryostabilization is an industrial technology governing the storage stabiliza- tion of frozen, freezer-stored, and freeze-dried food products. This technology emerged from a unified basic research program in food polymer science, and de- veloped from a fundamental understanding of the critical physico-chemical and thermomechanical structure/property principles which control the behavior of water in aqueous food systems at low temperatures. Cryostabilization is a means of protecting products, stored for long periods at typical freezer temperature, from the deleterious changes in texture (i.e. grain growth of ice, solute cry- stallization), structure (i.e. shrinkage, collapse), and chemical composition
(i.e. enzymic activity, oxidative reactions, flavor/color degradation) typical- ly encountered. The key to this protection, and the resulting improvement in storage stability, lies in controlling the physico-chemical and thermomechani- cal properties, by controlling the structural state, of the amorphous matrix surrounding the ice crystals in a frozen food. If this matrix is maintained as a kinetically-metastable mechanical solid (a glass), then the changes that ty- pically result in reduced quality and storage stability can be virtually pre- vented or greatly inhibited. If, on the other hand, a natural food material is improperly stored (at too high a freezer temperature) or a fabricated product is improperly formulated, and thus the matrix is allowed to exist in the freez- er as a rubbery fluid, then freezer-storage stability is reduced. Optimum free- zer temperature for a natural material or optimum formula for a fabricated pro- duct is dictated by the characteristic glass transition temperature, Tg', of the particular amorphous solute(s)/unfrozen water matrix, which is governed in turn by the average molecular weight of the specific combination of water-solu- ble solids in a complex food system. Moreover, the dynamic behavior of rubbery frozen food systems during storage is kinetically controlled, and the rates of deleterious changes are quantitatively determined by the /\T between T freezer and Tg'. These rates increase exponentially with increasing /\T above Tg', as defined by Williams-Landel-Ferry, rather than Arrhenius, kinetics.
Experimental results for a broad spectrum of frozen, freezer-stored, and freeze
-dried food products led to the identification of a class of common water-solu- ble food additives we call polymeric cryostabilizers, including, e.g., starch hydrolysis products such as low-DE dextrins and maltodextrins, proteins such as gelatin and gluten, and polysaccharides such as polydextrose and gums. Our ex- tensive investigations of these polymeric cryostabilizers led to a theoretical- ly-based understanding of their stabilizing functionality (via their influence on the structural state of a complex amorphous matrix). This functionality de- rives from their high MW, and the resulting elevating effect of these materials on a complex food system's characteristic Tg'. Increased Tg' leads to decreased
/\T, which in turn results in decreased rates of change during storage, and so increased storage stability. In this lecture, we will illustrate the principles of cryostabilization technology, as practically applicable to optimum storage of natural materials and formulation of fabricated products (containing poly- meric cryostabilizers) with dramatically improved storage stability, with a wide range of non-proprietary examples of actual food product systems, includ- ing frozen fruits, vegetables, dairy products, desserts, novelties, and bread dough, and freeze-dried fruits, vegetables, soluble coffees, juices, and other carbohydrate-based food and beverage powders.
[H13-2e]

ASPECTS OF STARCH AS A PARTIALLY CRYSTALLINE, WATER-COMPATIBLE POLYMER
THAT IS A MAJOR CONSTITUENT OF BAKED GOODS
Louise Slade and Harry Levine
ABSTRACT: Native granular starches, normal and waxy, ex-
hibit the non-equilibrium melting, annealing, and recrys-
tallization behavior characteristic of a kinetically-me-
tastable, water-plasticized, partially-crystalline poly-
mer system with a small extent of crystallinity. In this
lecture, we review recent advances in studies of starch
as a water-compatible food polymer, based on a classical
polymer science approach to structure/property relations.
Aqueous starch gels crystallized from an undercooled rub-
bery melt, as well as native granules, can be described
by the "fringed micelle" morphological model for a 3-di-
mensional, metastable polymer network composed of hydrat-
ed microcrystalline junction zones crosslinking plastici-
zed amorphous regions of randomly-coiled, possibly-entan-
gled chain segments. For native, freshly-gelatinized, and
retrograded starches alike, thermal analysis by Differen-
tial Scanning Calorimetry has revealed the critical role
of water as a plasticizer of amorphous and partially-cry-
stalline starch systems at low moisture, and the import-
ance of the glass transition as a physico-chemical param-
eter that can govern starch properties, processing, and
stability. DSC results have shown that starch gelatiniza-
tion is a non-equilibrium, kinetically-controlled melting
process, for which the Flory-Huggins thermodynamic treat-
ment of melting-point depression by diluent has no theor-
etical basis. Starch retrogradation exemplifies a thermo-
reversible gelation-via-(re)crystallization process with
a typical 3-step sequential mechanism of nucleation, pro-
pagation, and maturation. Rate and extent of retrograda-
tion as functions of temperature, for starch:water melts
within the rubbery region from Tg to Tm, can be described
by a classical theory of crystallization kinetics develo-
ped for synthetic partially-crystalline polymers. Several
aspects of this non-equilibrium process prevent theoreti-
cal interpretations of starch recrystallization based on
the Avrami equation. The non-Arrhenius kinetics of starch
retrogradation depend on the magnitude of T above Tg,
as defined by a relaxation time-temperature transformati-
on derived from Williams-Landel-Ferry free volume theory.
_________________________________________________________
Reproduced, with permission, from Slade, L. & Levine, H. (1987). Recent
Advances in Starch Retrogradation, in Recent Developments in Industrial
Polysaccharides (eds. S.S. Stivala, V. Crescenzi & I.C.M. Dea), Gordon &
Breach Science, New York, 387-430.
[H13-2f]

POLYMER PHYSICOCHEMICAL PROPERTIES OF GLUTEN AND OTHER PROTEINS IN BAKED GOODS
Harry Levine and Louise Slade
A) EFFECT OF GLASS TRANSITION TEMPERATURE ON PROTEIN FUNCTIONALITY IN FOODS
This talk will review the "food polymer science" (FPS) approach to studies of the effect of the glass transition temperature (Tg) on protein functionality in various food applications. The FPS approach emphasizes the dynamic, non-equilib- rium nature of "real world" food systems. Many such food systems comprise amor- phous components that are characterized by their Tg and by the effect thereon of plasticization by water. The behavior of such amorphous food materials and prod- ucts, including many common proteins (e.g. wheat gluten, gelatin, corn zein, soy globulin, casein), is described by means of state diagrams of temperature vs. composition. Such state diagrams are used to understand various aspects of food technology, such as the storage stability of frozen or freeze-dried, protein- based foods. The FPS approach also provides a means of relating mechanical and sensory textural properties of protein-containing foods, such as baked goods, to
Tg and the effect of plasticization by water. Examples of such baked goods, in which protein functionality is governed by the relationship between Tg and the temperature of processing or storage, include white pan bread, ice cream cones, and cookies and crackers. These examples will be highlighted in this talk.
B) POLYMER PHYSICOCHEMICAL PROPERTIES OF GELATIN IN FOODS
Gelatin is an important industrial biopolymer, particularly as a food ingredient. Gelatin is also a partially-crystalline glassy polymer (PCGP), whose properties can be characterized based on a polymer-chemical approach. Thermal analysis by Differential Scanning Calorimetry demonstrates that gelatin exhibits the non-equilibrium melting behavior characteristic of a metastable PCGP with a relatively small extent of crystallinity. Aqueous gelatin gels can be represent- ed by the well-known "Fringed Micelle" model for a 3-dimensional metastable network composed of amorphous regions containing plasticizing water and hydrated crystalline regions which serve as junction zones. The mechanism of gelation involves a typical three-sequential-step polymer crystallization process of nucleation (initiation of helical chain segments), propagation (crystal growth by aggregation of helices), and maturation (crystal perfection or continued growth). Gel melting is a non-equilibrium process, in which the melting of the microcrystallites is controlled by the prerequisite softening of the random-coil chain segments in the glassy regions of the Fringed Micelle structure. Gelatin gels exhibit two sequential thermal transitions on heating to 130øC: Tg (glass transition or softening temperature) of the continuous amorphous phase allowing the subsequent Tm (non-equilibrium melting temperature) of the intermolecular crystalline junctions. Both transition temperatures are moisture-dependent, increasing and converging with decreasing moisture content. Many of the major food-related and other industrial applications of gelatin, some of which are based on gelatin's moisture-managing functionality, are shown to be based on these polymeric structure/property relationships.
[Slade, L. & Levine, H. (1987). In Advances in Meat Research, Vol. 4 - Collagen as a Food (eds. A.M. Pearson, T.R. Dutson & A. Bailey), Westport, AVI, 251-266.]
The polymer physicochemical properties of other important food proteins, especially gluten, but also including casein, soy, and elastin, are compared and contrasted with those of gelatin.
[H13-2g]

FOOD POLYMER SCIENCE APPROACH TO INGREDIENT FUNCTIONALITY
IN COOKIE/CRACKER BAKING TECHNOLOGY
Louise Slade and Harry Levine
SUMMARY
While the potential functionality of wheat flours is determined predominantly by the genetics of the wheat, climatic conditions during its growth, and the skill with which it is milled, expression of flour functionality during the unit operations of mixing, machining, baking, and storage is determined predomi- nantly by the evolving environment of the flour in the dough and baked product.
The ability to control wheat genetics shows promise, but the baking industry has no influence over climate or the condition of break rolls. Little opportunity for control of the flour environment through formulation exists for very lean white pan bread and cracker systems; selection of the flour raw material is the key to a successful process and product. In contrast, through an understanding of the structure-function relationships of sucrose, flours, leavening agents, and enzymes in rich cracker and cookie systems, the baker can control: 1) the swelling of flour polymers, dissolution of sucrose, and development of dough during mixing; 2) the evolution of geometry, further dissolution of sucrose, drying profile, gelatinization and pasting of starch, thermosetting of gluten, and Maillard browning reaction kinetics during baking; and 3) the textural hard- ness, moisture relations, and attribute stability during product storage.
A polymer science approach addresses the mechanical, physical- and chemical-
(i.e. solubility parameter) thermodynamic, and kinetic aspects of flour and sucrose as food polymers, in order to facilitate a necessary understanding of their functionality by distinguishing the principles of: 1) the thermodynamic compatibility of sucrose-water as a swelling solvent with flour polymers vs. the kinetic mobility of sucrose-water as an antiplasticizer of gluten develop- ment and starch gelatinization/pasting; 2) the mechanical contribution of crys- talline sucrose vs. the kinetic contribution of sucrose in solution to cream and dough rheology; and 3) the thermodynamic driving force and extent vs. the kinetic constraint and rate of sucrose dissolution. The central focus of a food polymer science approach to understanding cookie and rich cracker systems is a complete state diagram for sucrose, which provides both a mobility transforma- tion map to predict what will actually happen and a thermodynamic stability map to indicate the limiting cases for what could ever happen. Transformations of time-temperature-sucrose concentration can be viewed as alternative paths traced during the unit operations from alternative initial and final locations on the mobility map. The instantaneous value of total sucrose concentration (i.e. the ratio of total sucrose/water) determines the location on the thermodynamic sta- bility map. The instantaneous value of dissolved sucrose concentration deter- mines the location on the mobility map. Alternative initial and final locations and process pathways on the sucrose state diagram lead to predictable differ- ences in baking performance, product quality attributes, and storage stability.
===============================================================================
Reproduced, with permission, from Slade, L. and Levine, H. (1991c). Structure-
Function Relationships of Cookie and Cracker Ingredients. In The Science of
Cookie and Cracker Production, ed. H. Faridi, Van Nostrand Reinhold/AVI, New
York, pp. 23-141.
[H13-2k]

EXAMPLES OF APPLICATIONS OF MOST INTEREST TO PARTICIPANTS
Harry Levine and Louise Slade
OUTLINE
=======
* Participant Contributions
* Review of Application Examples
* Review of Case Studies
* How to Capitalize on Food Polymer Science
Approach in Industrial R&D Labs
* Discussion, "Next Steps", and Follow-Up
[H13-2k]

SHORT READING LIST FOR COURSE [H18-6d]
=============================
1. Slade, L. and Levine, H. (1991). Beyond Water Activity: Recent Advances
Based on an Alternative Approach to the Assessment of Food Quality and
Safety. CRC Crit. Revs. Food Sci. Nutr. 30(2-3): 115-360.
2. Levine, H. and Slade, L. (1992). Glass Transitions in Foods, in Physical
Chemistry of Foods, eds. H.G. Schwartzberg and R.W. Hartel, Marcel Dekker,
New York, pp. 83-221.
3. Slade, L. and Levine, H. (1995). Glass Transitions and Water-Food Structure
Interactions. In Advances in Food and Nutrition Research, vol. 38, ed. J.E.
Kinsella, Academic Press, San Diego, pp. 103-269.
4. Levine, H. and Slade, L. (eds.) (1991). Water Relationships in Foods,
Plenum Press, New York.

COURSE BIBLIOGRAPHY (H13-2h)
A. General References -
1. Water - A Comprehensive Treatise. Volume 7: Water and Aqueous Solutions
at Subzero Temperatures (Felix Franks, ed.). Plenum Press: NY, 1982.
2. Water - A Comprehensive Treatise. Volume 1: The Physics and Physical
Chemistry of Water (Felix Franks, ed.). Plenum Press: NY, 1972.
3. Water. Felix Franks, Royal Society of Chemistry, London, 1983.
4. Water in Polymers. ACS Symposium Series 127 (S.P. Rowland, ed.). American
Chemical Society: Washington, DC, 1980.
5. Properties of Water in Foods (D. Simatos & J.L. Multon, eds.). Martinus
Nijhoff: Dordrecht, 1985.
6. Water Activity - Influences on Food Quality (L.B. Rockland & G.F.
Stewart, eds.). Academic Press: NY, 1981.
7. Water Relations of Foods (R.B. Duckworth, ed.). Academic Press: NY, 1975.
8. Water Activity - Theory and Applications to Food (L.B. Rockland & L.R.
Beuchat, eds.). Marcel Dekker: NY, 1987.
9. Water Science Reviews 3 - Water Dynamics (F. Franks, ed.). Cambridge
University Press: Cambridge, 1988.
10. Food Preservation by Moisture Control (C.C. Seow, ed.). Elsevier Applied
Science: London, 1988.
11. Thermal Analysis of Foods (C.-Y. Ma & V.R. Harwalkar, eds.). Elsevier
Applied Science: London, 1990.
12. Water Relationships in Foods (H. Levine & L. Slade, eds.). Plenum Press:
New York, 1991.
13. The Glassy State in Foods (J.M.V. Blanshard & P.J. Lillford, eds.).
Nottingham University Press: Loughborough, 1993.
14. Water in Foods: Fundamental Aspects and their Significance in the Process-
ing of Foods - Proceedings of ISOPOW-V" (P. Fito & A. Mulet, eds.), Else-
vier Applied Science: London, 1994; J. Food Eng. 22(1-4), 1994.
15. Phase Transitions in Foods. Yrjo Roos, Academic Press, San Diego, 1995.
16. Food Preservation by Moisture Control (G.V. Barbosa-Canovas & J. Welti-
Chanes, eds.). Technomic: Lancaster, PA, 1995.
17. Recent Advances in Applications of Thermal Analysis to Foods, Special
Issue of Journal of Thermal Analysis, vol. 47(5), eds. H. Levine and L.
Slade, 1996.
18. The Properties of Water in Foods - ISOPOW 6 (D.S. Reid, ed.). Blackie
Academic & Professional: London, 1998.
19. Phase/State Transitions in Foods (M.A. Rao and R.W. Hartel, eds.). Marcel
Dekker, NY, 1998.
20. Water Management in the Design and Distribution of Quality Foods - ISOPOW 7
(Y.H. Roos, R.B. Leslie, and P.J. Lillford). Technomic, Lancaster, PA, 1999.
21. Crystallization in Foods. Richard W. Hartel, Aspen Publ., Gaithersburg MD,
2001.
22. Water: 2nd Edition - A Matrix of Life. Felix Franks, Royal Soc. Chem.,
Cambridge, UK, 2000.
23. Water Science for Food, Health, Agriculture and environment - ISOPOW 8 (Z.
Berk, R.B. Leslie, P.J. Lillford, and S. Mizrahi, eds.). Technomic,
Lancaster, PA, 2001.
24. Amorphous Food and Pharmaceutical Systems (ed. H. Levine). Royal Society of
Chemistry, Cambridge, UK, 2002.
25. Characterization of Cereals and Flours - Properties, Analysis, and Applica-
tions (G. Kaletunc and K.J. Breslauer, eds.). Marcel Dekker, NY, 2003.
26. Physical Principles of Food Preservation. Marcus Karel and Daryl B. Lund,
Marcel Dekker, NY, 2003.

GLOSSARY OF ABBREVIATIONS AND SYMBOLS [H13-2k]
=====================================
AACC American Association of Cereal Chemists
AB Ana Bravo
ABC ammonium bicarbonate
Am L amylose-lipid complex
Ap amylopectin
AVG average cm centimeter(s) cm2 square centimeter(s)
CV% coefficient of variance cwt centiweight(s) d diameter endo endotherm eqv W expansion work
Ew elasticity exo exotherm
FF full factorial
FGS fine-granulated sugar
FM flour moisture content fwb flour, wet basis g gram(s) h height
HFCS high-fructose corn syrup
Histra alpha-amylase enzyme
HRW hard red winter wheat
HYCO plastic shortening
H2O water l length lb pound(s)
L alveograph parameter
LFRA Leatherhead Food Research Association dough viscosity m moisture mcal/deg milli-calories per degree mm millimeter(s) m% moisture content
NFDM non-fat dry milk
OAAT one-at-a-time
OH Ohio oz ounce(s) pH potential of Hydrogen
P alveograph parameter
PEN pentosanase enzyme
PNW pacific northwest
PS predissolved sucrose r correlation coefficient
RH relative humidity
R.H.% percent relative humidity
RVP relative vapor pressure s sucrose sec second(s) sh stack height
SODA sodium bicarbonate
SOY soy oil
SRW soft red winter wheat
SW soft white wheat
SWC soft white club wheat
T temperature
Tm melting temperature
TS or ts total solvent
T SOLVENT total solvent
V volume w width
W alveograph parameter wt weight x times
YSw yield stress
æJ/cc micro Joules per cubic centimeter
%m percent moisture

%SUC percent sucrose concentration
2X2 two factors at two levels
3X2 three factors at two levels
3X3 three factors at three levels