Table of Contents
Cover
Title Page
Copyright
List of Contributors
Preface
Chapter 1: Thermal and Relaxation Properties of Food and Biopolymers with Emphasis on Water
1.1 Introduction
1.2 Glass Transition and Relaxation Dynamics of Sugar Solutions and Sugar-Rich Food
1.3 Glass Transition and Relaxation Dynamics of Proteins
1.4 Confined Aqueous Solutions and the Failure of Gordon-Taylor Extrapolations to High-Water Contents
1.5 Concluding Discussion
References
Chapter 2: Glass Transition Thermodynamics and Kinetics
2.1 Introduction
2.2 Theories of Glass Transition
2.3 Reaction Kinetics – Basic Principle
2.4 Reaction Kinetics – Temperature Dependence
2.5 Glass Transition in Sugars
2.6 Glass Transition in Dairy Ingredients
2.7 Glass Transition in Fruit Powders
2.8 Conclusion and Direction for Future Studies
References
Chapter 3: Glass Transition of Globular Proteins from Thermal and High Pressure Perspectives
3.1 Factors Affecting Protein Functionality
3.2 High-Pressure Processing
3.3 Specific Examples of Pressure Effects
3.4 The Time-temperature-pressure Effect on the Vitrification of High Solid Systems
3.5 High Pressure Effects on the Structural Properties of Condensed Globular Proteins
3.6 Concluding Remarks
References
Chapter 4: Crystal-Melt Phase Change of Food and Biopolymers
4.1 Introduction
4.2 Thermodynamics of Crystallization and Melting
4.3 Role of Water in the Phase Transition of Food
4.4 Classification of Phase Transitions
4.5 Crystallization, Melting and Morphology
4.6 Crystal Growth
4.7 Crystallization Kinetics
4.8 Crystal Melting and Morphology
4.9 Conclusions
Acknowledgements
References
Chapter 5: Thermal Properties of Food and Biopolymer Using Relaxation Techniques
5.1 Introduction
5.2 Relaxation Through Nuclear Magnetic Resonance (NMR)
5.3 Relaxation Through Dielectric Spectroscopy
5.4 Relaxation Through Differential Scanning Calorimetry (DSC)
5.5 Relaxation Through Dynamic Mechanical Measurements
5.6 Conclusions
Acknowledgement
References
Chapter 6: Plasticizers for Biopolymer Films
6.1 Introduction
6.2 Plasticizer Classification
6.3 Mechanisms of Plasticization
6.4 Plasticizers for Protein-Based Films
6.5 Polysaccharide-Based Films
6.6 Plasticizers for Poly(lactic acid) Films
6.7 Conclusion
References
Chapter 7: Crystallization Kinetics and Applications to Food and Biopolymers
7.1 Introduction
7.2 Crystal Growth and Nucleation
7.3 Shape of Crystals
7.4 Polymorphism
7.5 Crystallization Kinetics
7.6 Isothermal Crystallization
7.7 Non-Isothermal Crystallization Kinetics
7.8 Ozawa Model
7.9 Crystallization in Foods
7.10 Selected Case Studies
7.11 Conclusion
References
Chapter 8: Thermal Transitions, Mechanical Relaxations and Microstructure of Hydrated Gluten Networks
8.1 Introduction
8.2 Thermal Transitions of Hydrated Gluten Networks
8.3 Mechanical Relaxations of Hydrated Gluten Network
8.4 Calculation of Relaxation Spectra of Hydrated Gluten Networks
8.5 Microstructure of Gluten Network
8.6 Concluding Remarks
References
Chapter 9: Implication of Glass Transition to Drying and Stability of Dried Foods
9.1 Introduction
9.2 The Glass Transition
9.3 Structural Relaxations
9.4 Drying and Dehydrated Solids
9.5 Conclusion
References
Chapter 10: Water-Glass Transition Temperature Profile During Spray Drying of Sugar-Rich Foods
10.1 Introduction
10.2 Spray Dryer
10.3 Glass Transition
10.4 Issues Related with Sugar-Rich Foods
10.5 Stickiness, Deposition and Caking
10.6 Modeling and Prediction of T
g
Profile
10.7 Strategies to Reduce Stickiness in Sugar-Rich Foods
10.8 Conclusions
References
Chapter 11: State Diagram of Foods and Its Importance to Food Stability During Storage and Processing
11.1 Introduction
11.2 State Diagram and Their Boundaries
11.3 BET-Momolayer Line
11.4 Water Boiling and Solids-Melting Lines
11.5 Macro-Micro Region in the State Diagram
11.6 Applications of State Diagram in Determining Food Stability
Acknowledgement
References
Chapter 12: Thermal Properties of Polylactides and Stereocomplex
12.1 Introduction
12.2 PLA and its Isomers
12.3 Thermal Property Measurement
12.4 Glass Transition Temperatures
12.5 Melting Behavior of PLA
12.6 Thermal Properties of Stereocomplexed Polylactides
12.7 Crystallinity of PLA
12.8 Conclusions
References
Chapter 13: Thermal Properties of Gelatin and Chitosan
13.1 Introduction
13.2 Thermal Properties of Gelatin
13.3 Thermal Properties of Gelatin-Based Film
13.4 Thermal Transition by TGA
13.5 Thermal Properties of Chitosan
13.6 Conclusion
References
Chapter 14: Protein Characterization by Thermal Property Measurement
14.1 Introduction
14.2 Differential Scanning Calorimeter (DSC)
14.3 Isothermal Titration Calorimetry
14.4 Differential Scanning Fluorimetry (DSF)/Thermal Shift Assay
14.5 Thermogravimetric Analysis (TGA)
14.6 Differential Thermal Analysis (DTA)
14.7 Thermomechanical Analysis (TMA)
14.8 Dynamic Thermo-Mechanical Analysis (DMA)
14.9 Thermal Conductivity
14.10 Conclusion
14.11 Future Prospective of Thermal Methods of Characterization
References
Chapter 15: High-Pressure Water-Ice Transitions in Aqueous and Food Systems
15.1 Introduction
15.2 Water-Ice Transitions Under High Pressure
15.3 High-Pressure Freezing
15.4 High-Pressure Thawing
15.5 Principle of High-Pressure Thawing
15.6 Effect of HPT on Quality of Selected Foods
15.7 HPT on Microbial Growth
References
Chapter 16: Pasting Properties of Starch: Effect of Particle Size, Hydrocolloids and High Pressure
16.1 Introduction
16.2 Pasting Properties
16.3 Rheological Measurement
16.4 Starch Pasting Cell
16.5 Effect of Hydrocolloids and Emulsifiers on Pasting Properties of Starch
16.6 Effect of Particle Size on Pasting Properties of Flour Rich in Starch
16.7 Effect of Drying on Pasting Properties
16.8 Effect of High Pressure on Pasting Properties
16.9 Pasting Properties of Blends of Starches
16.10 Conclusions
References
Index
End User License Agreement
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Guide
Cover
Table of Contents
Preface
Begin Reading
List of Illustrations
Chapter 1: Thermal and Relaxation Properties of Food and Biopolymers with Emphasis on Water
Figure 1.1 Schematic description of the so-called “No man's land” of water between 150 and 230 K. In this region crystallisation of bulk water and aqueous solutions of higher water contents cannot be avoided. 273 K is the melting temperature of bulk water.
Figure 1.2 Gordon-Taylor plot of glass transition temperatures obtained from DSC measurements. The glass transition temperatures of the dry carbohydrates and carbohydrates with 10 wt% water content are taken from Fulcher
et al
. (Fulcher, 1925). The inset shows DSC data around the glass transition of glucose at the hydration levels 25, 30 and 35 wt% water. The glass transition temperature,
T
g
, was taken as the half step of the transition on cooling. The cooling rate for all measurements was 10 °C/min. The Figure is taken from Jansson
et al
. (Jansson
et al.
2005).
Figure 1.3 Schematic relaxation behaviour of a typical supercooled liquid. The relaxation process that is coupled to the macroscopic viscosity of the liquid is called the α-relaxation, which reaches a time scale of about 100 s at
T
g
. However, slightly above
T
g
, one or more local relaxation processes decouple from the structural α-relaxation. Such secondary relaxation processes are often denoted β-relaxations.
Figure 1.4 Dielectric relaxation times for the sugars fructose, glucose and xylitol containing 20 wt% water and freeze-dried strawberry at the same hydration level. The viscosity related α-relaxation of each system is given by solid lines and the more local water relaxation (w) is given by the symbols shown in the figure.
Figure 1.5 Temperature dependence of the power-law exponent
n
of the conductivity contribution ((σ/(ϵ
0
ω)
n
) to the imaginary part of the dielectric permittivity of the hydrated strawberry sample. The increase of
n
with increasing temperature is due to a transition from restricted ionic motions in cavities of the strawberry matrix to long-range ionic motions when the matrix is sufficiently mobile to “open up” the cavities. The Figure is redrawn from Jansson
et al
. (Jansson
et al.
2005).
Figure 1.6 DSC curves obtained for myoglobin in water-glycerol mixtures. The water content in the solvent (in wt%) and the total solvent content h in g solvent per g myoglobin are given in each Figure The insets show the derivative of the heat flow with respect to the temperature, from which the broadness of the glass transition range was determined.
Figure 1.7 (a) Calorimetric glass transition temperature
T
g
(determined by the inflection point), and (b) broadness of the glass transition range Δ
T
g
(the whole transition range estimated from the derivative of the heat flow with respect to the temperature, as shown in the inset of Figure 1.6)) are shown as a function of wt% water in the solvent for different solvent contents h. The error in Δ
T
g
is ±5 K. The Figure is redrawn from Jansson
et al
. (Jansson
et al.
2011).
Figure 1.8 (a) Temperature evolution of the imaginary part of the dielectric permittivity vs frequency for myoglobin in a water-glycerol mixture of 33 wt% water and a total solvent content of h=1. In (b) the curve fitting is shown to visualize how the relaxation times of the different relaxation processes were extracted from the measured data. The Figure is redrawn from Jansson
et al
. (Jansson, H.
et al.
2011).
Figure 1.9 Dielectric relaxation times for the same six myoglobin samples as shown in Figure 1.6. Also shown in the Figure are the calorimetric glass transition ranges, Δ
T
g
, obtained in Figure 1.6. The solid lines show the results of the curve fitting (by Eq. 1.3) of the temperature dependence of the main solvent relaxation in the high temperature range.
Figure 1.10 Relaxation times of the protein processes are shown as a function of the relaxation time of the α-process in the solvent. The protein processes are the same (same symbols) as shown in Figure 1.9. Note the almost perfect linear dependences for all protein processes and samples, except for the hydrated samples (e and f) where the temperature dependences of the protein relaxations are difficult to determine with good accuracy.
Figure 1.11 DSC heating scans of water-glycerol solutions confined in the 21 Å pores of MCM-41 C10. The concentration of water in each solution is given in the Figure The curves are vertically shifted for clarity. The Figure is redrawn from Elamin
et al
. (Elamin
et al.
2013).
Figure 1.12 Concentration dependences of the glass transition temperature. Calorimetric values are shown for both confined solutions, obtained from the DSC data shown in Figure 1.11 (solid squares), and bulk solutions (open squares). Dynamic glass transitions, estimated as the temperature where the α-relaxation reaches a time scale of 100 s, are also shown for the confined solutions (solid circles). The dashed lines between the data points are just a guide for the eye. The Figure is redrawn from Elamin
et al
. (Elamin
et al.
2013).
Figure 1.13 Arrhenius plot of dielectric relaxation times of the α and w (or β) processes of the confined solutions. The water concentration of each sample is given in the Figure The Figure is redrawn from Elamin
et al
. (Elamin
et al.
2013).
Figure 1.14 (a) A schematic description of a typical temperature dependence of the viscosity related α-relaxation in a bulk liquid. The Figure shows how the activation energy increases with decreasing temperature due to an increasing number of molecules involved in the cooperative rearrangement of molecules associated to the relaxation process. (b) A possible relaxation scenario for confined water. In this case the length-scale of the cooperativity can no longer grow with decreasing temperature if the cooperativity length exceeds the size of the geometrical confinement. Instead, a crossover to a more local (β-like) relaxation occurs. Figure (a) is redrawn from Monasterio
et al.
(Monasterio
et al.
2013).
Chapter 3: Glass Transition of Globular Proteins from Thermal and High Pressure Perspectives
Figure 3.1 Folding, unfolding and aggregation model of protein (with permission from Kasapis
et al
. 2009).
Figure 3.2 (a) Gelation temperature versus
R
for BSA 8% w/w. Symbols represent threshold times for gelation: open circles, 100 s; filled circles, 1000 s; triangle up, 10000 s;
R
is the molar ratio and depends on the concentration of sodium chloride contained in BSA and the concentration of added salt, where
R
= 9 is the sample with no sodium addition (with permission from Tobitani & Ross-Murphy, 1997); (b) dependence of the mean droplet diameter (
d
32
) on the pH of the emulsion. Extensive droplet aggregation is observed around the isoelectric point of the whey proteins, that is, pH ∼4.8 (with permission from Demetriades, Coupland, & McClements, 1997); (c) effect of pH on foam strength of 0.1% (w/w) ovalbumin at 10 °C (with permission from Waniska & Kinsella, 1979).
Figure 3.3 High hydrostatic pressure equipment: (a) pump/intensifier, and (b) monoblock casting technology for moderate pressure/size vessels and wire-winding technology for vessels used in larger size and higher pressure applications (with permission from Torres & Velazquez, 2005).
Figure 3.4 (a) General scheme of the pressure-temperature phase diagram of proteins (with permission from Messens
et al
. 1997); (b) effect of high-pressure treatment on emulsifying capacity (treatment time, 10 min); β-lactoglobulin concentration: (
) 0.3 mg/ml; (
) 1.0 mg/mL; (
) 1.5 mg/mL (with permission from Pittia
et al
. 1996a); (c) surface hydrophobicity of β-lactoglobulin in solution determined by the ANS method, as related to high-pressure treatment time (with permission from Pittia
et al
. 1996a).
Figure 3.5 (a) Comparison of the elastic component E′ and the viscous component E″ of the surface viscoelastic modulus as a function of air bubble volume oscillation frequency between non-treated and 300 MPa-treated WPI solutions. E′ native WPI (
), E′ 300 MPa-treated WPI (
), E″ native WPI (
), E″ 300 MPa-treated WPI (
) (with permission from Bouaouina
et al
. 2006); (b) foam stability (FS%) as a function of high pressure treatment time for 0.2 mg/ml β-casein treated at different pressures: (
) 300 MPa, (
) 600 MPa, (
) 900 MPa (with permission from Pittia
et al
. 1996b).
Figure 3.6 (a) Cooling profiles of storage (
) and loss (
) modulus for 15% whey protein isolate with 65% glucose syrup scanned at 1 °C/min (frequency: 1rad/s; strain: 0.01%); (b) master curve of reduced shear moduli (
G'
p
and
G″
p
) for 15% whey protein isolate with 65% glucose syrup as a function of reduced frequency of oscillation (ω
a
T
) at the reference temperature of 2 °C; (c) temperature variation of the factor
a
T
within the glass transition region (
) and glassy state (
) for 15% whey protein isolate with 65% glucose syrup, and glass transition region (
) and glassy state (
) of 80% glucose syrup, with the solid lines reflecting the WLF and modified Arrhenius fits of the shift factors throughout the vitrification regime (dashed line pinpoints the mechanical
T
g
predictions) (with permission from Kasapis & Shrinivas, 2010; George, Lundin, & Kasapis, 2012).
Figure 3.7 (a) Temperature variation of shear moduli for 2% gellan plus 76% glucose syrup (6.7 mM CaCl
2
added) at a scan rate of 1 °C/min and a strain range of 0.00071 to 1%. Prior to mechanical analysis, gels were pressurized at 0.1 [
G'
(
);
G″
(
)] and 700 [
G'
(
);
G″
(
)] MPa (with permission from Kasapis & Sablani, 2005); (b) isothermal data of shear relaxation modulus from 1 to 4600 bars (A), and others (isobaric) (B) for Hypalon 40 at different temperatures (from 25 to −25 °C) reduced to 1 bar and 25 °C by shift factors
a
T,P
(with permission from Fillers & Tschoegl, 1977).
Figure 3.8 (a) MDSC thermograms of 30, 40, 50, 68 and 80% WPI samples during heating from 25 to 95 °C at a heating rate of 2 °C/min arranged successively downwards; samples at atmospheric pressure are in the bottom of figure, whereas samples after pressurizing at 600 MPa for 15 min are on top of the figure; (b) FTIR spectra of 30, 40, 50, 68 and 80% (w/w) WPI samples either at atmospheric pressure or after pressurizing.
Figure 3.9 (a) Variation of storage modulus (
G'
) of 80% (w/w) WPI samples at constant frequency of 1 rad/s and strain of 0.001%; sample at atmospheric pressure (open symbols) was heated from 25 to 85 °C, held at 85 °C for 20 min and cooled down to −30 °C; sample pressurized at 600 MPa for 15 min (closed symbols) was cooled from 25 °C to −30 °C; (b) master curves of reduced shear modulus,
G'
p
(
,
) and
G″
p
(
,
), for the samples of 80% (w/w) WPI at atmospheric conditions (open symbols) and pressurized at 600 MPa for 15 min (closed symbols), as a function of reduced frequency of oscillation (ω
a
T
) using the frequency sweeps acquired at the range of –28 to 6 °C for atmospheric samples and –31 to 5 °C for pressurized samples, with the reference temperatures of −8 °C and −11 °C, respectively; (c) temperature variation of factor
a
T
within the glass transition region (closed symbols) and the glassy state (open symbols) for 80% (w/w) WPI samples at atmospheric conditions (circles) and pressurised at 600 MPa for 15 min (triangles).
Figure 3.10 MDSC thermograms from 25 to 100 °C at a scan rate of 2 °C/min of (a) atmospheric and (b) pressure treated (600 MPa; 15 min) WP/lactose samples of 30, 40, 50, 68 and 80% total solids arranged successively downwards; (c) FTIR spectra of 30, 40, 50, 68 and 80% (w/w) WP/lactose samples either at atmospheric pressure or after pressurizing at 600 MPa for 15 min.
Figure 3.11 (a) Variation of storage modulus (
G'
) for 80% WP/lactose samples at frequency of 1 rad/s and strain of 0.001%; samples at atmospheric pressure (shown in open symbols) were heated from 25 to 85 °C, held at 85 °C for 20 min and cooled down to −33 °C, and samples after pressurizing at 600 MPa for 15 m (in closed symbols) were cooled from 25 °C to −48 °C; (b) master curves of reduced shear modulus [
G'
p
(
,
);
G″
p
(
,
)] for 80% WP/lactose samples at atmospheric pressure (shown in open symbols) and pressurized at 600 MPa for 15 min (in closed symbols), as a function of reduced frequency of oscillation (ω
a
T
), with reference temperatures for the horizontal superposition of mechanical data being −1 and −16 °C, respectively; (c) temperature variation of factor
a
T
within the glass transition region (closed symbols) and the glassy state (open symbols) for 80% WP/lactose samples at the atmospheric (
,
) or pressurised (
,
) state; solid lines reflect the WLF and modified Arrhenius fits of the shift factors during the vitrification process, with dashed lines indicating the corresponding
T
g
predictions.
Figure 3.12 (a) microDSC thermograms of 60, 70 and 80% (w/w) immunoglobulin samples during heating from 35 to 95 °C at a heating rate of 2 °C/min; samples at atmospheric pressure are in the bottom of figure, whereas samples after pressurizing at 600 MPa for 15 min are on top of the figure; secondary conformation of immunoglobulins at (b) 60 and (c) 80% total solids as observed by infrared spectroscopy.
Figure 3.13 (a) Variation of storage modulus (
G'
) for 80% immunoglobulin samples at frequency of 1 rad/s and strain of 0.001%; samples at atmospheric pressure (shown in open symbols) were heated from 35 to 85 °C, held at 85 °C for 15 min and cooled down to −48 °C, and samples after pressurizing at 600 MPa for 15 min (closed symbols) were cooled from 20 °C to −44 °C (scan rate of 2 °C/min); frequency variation of (b)
G'
and (c)
G″
for 80% immunoglobulin samples after high pressure processing; bottom curve was taken at 0 °C () and other curves successively upwards −4 (+), −8 (
), −12 (−), −16 (
), −20 (
), −24 (
), −28 (*), −32 (
), −36 (
) and −40 °C (
); (d) temperature variation of factor
a
T
within the glass transition region (
,
) and the glassy state (
,
) for 80% immunoglobulin samples at atmospheric pressure (shown in open symbols) and pressurized at 600 MPa for 15 min (in closed symbols).
Figure 3.14 (a) The extent of denaturation in pressurised soy glycinin samples; changes in absorbance as a function of soy glycinin concentration within Amide I (b) and Amide II (c) of 10 – 80% (w/w) soy glycinin samples either at atmospheric pressure (
), heat treatment at 80 °C for 10 min (
) and after pressurizing at 600 MPa for 15 min (
); (d) changes in α-helix content of soy glycinin at atmospheric pressure (
), after pressurization at 600 MPa for 15 min (
) and heat treatment (
) at 80 °C for 10 min observed for Amide I infrared spectroscopy.
Figure 3.15 (a) Variation of storage modulus (
G'
) of 80% (w/w) glycinin samples at a constant frequency of 1 rad/s and strain of 0.001%, sample at atmospheric pressure (
) was heated from 25 to 80 °C, held at 80 °C for 10 min and cooled down to −36 °C, and sample after pressurizing at 600 MPa for 15 min (
) was cooled directly from 25 to −36 °C; [
G'
p
(
) and
G″
p
(
)] as a function of reduced frequency of oscillation (ω
a
T
) for 80% glycinin samples at atmospheric pressure (b) and following pressurisation at 600 MPa for 15 min (c), master curve was plotted using the frequency sweeps acquired in the range of −30 to 14 °C; (d) temperature variation of factor α
T
within the glass transition and glassy state for atmospheric (
,
) and pressurized (
,
) sample of 80% soy glycinin, with the solid lines reflecting the WLF and modified Arrhenius fits of the shift factors in the glass transition region and glassy state, respectively (dashed lines pinpoint the
T
g
predictions).
Figure 3.16 (a) Extent of denaturation in pressurised ovalbumin samples; (b) changes in the amide I (b) region of 10 – 80% (w/w) ovalbumin samples either at atmospheric pressure (
), heat treatment at 85 °C for 20 min (
) and after pressurizing at 600 MPa for 15 min (
); (c) changes in β-sheets content of ovalbumin at atmospheric pressure (
), after pressurization at 600 MPa for 15 min (
) and heat treatment (
) at 80 °C for 10 min observed for Amide I infrared spectroscopy.
Figure 3.17 (a) Variation of storage modulus (
G'
) of 80% (w/w) ovalbumin samples at a constant frequency of 1 rad/s and strain of 0.001%; sample at atmospheric pressure (
) was heated from 25 to 85 °C, held at 85 °C for 20 min and cooled down to −37 °C, and sample after pressurizing at 600 MPa for 15 min (
) was cooled from 25 °C to −37 °C (scan rate of 2 °C/min); (b) frequency variation of
G'
for 80% ovalbumin samples at atmospheric pressure and master curve of reduced shear modulus (c) [
G'
p
(
) and
G″
p
(
)] as a function of reduced frequency of oscillation (ω
a
T
); the lowest curve was taken at 15 °C (
), other curves arranged successively upwards at 11 (
), 7 (
), 3 (
), −1 (
), −5 (
), −9 (
), −13 (
), −17 (
), −21 (+), −25 (
),−29 ( ), −33 (
) and −37 (
) °C; master curve were plotted using the frequency sweeps acquired at the range of −37 to 15 °C; (d) temperature variation of factor α
T
within the glass transition and glassy state for atmospheric (
,
) and pressurized (
,
) sample of 80% ovalbumin, with the solid lines reflecting the WLF and modified Arrhenius fits of the shift factors in the glass transition region and glassy state.
Figure 3.18 Microcalorimetry thermograms of 30, 40, 50, 55, 60, 65, 70, 75 and 80% (w/w) BSA samples during heating from 25 to 100 °C at a rate of 1 °C/min for (a) atmospheric pressure and (b) after pressurisation at 600 MPa for 15 min arranged successfully downwards; (c) absorbance variation as a function of concentration for the samples tested at atmospheric pressure (
), after pressurization at 600 MPa for 15 min (
) and with heat treatment at 85 °C for 20 min (
) observed by amide I infrared spectroscopy; (d) secondary conformation of BSA at 80% total solids (w/w).
Figure 3.19 (a) Variation of storage modulus (
G'
) for 80% (w/w) BSA at constant frequency of 1 rad/s and strain of 0.001%, with atmospheric pressure samples being heated from 25 to 85 °C, held at 85 °C for 20 min and cooled down to −20 °C (
), and pressurised samples at 600 MPa for 15 min being cooled from 25 °C to −80 °C (
); master curves of reduced shear modulus [
G'
p
(
) and
G″
p
(
)] as a function of reduced frequency of oscillation (ω
a
T
) for 80% (w/w) BSA samples at atmospheric (b) and pressurized (c) conditions; (d) temperature variation of factor
a
T
within the glass transition region (closed symbols) and the glassy state (open symbols) for 80% (w/w) BSA samples at atmospheric conditions (triangles) and pressurised at 600 MPa for 15 min (diamonds); solid lines reflect the WLF and modified Arrhenius fits of the shift factors during the vitrification process, with the dashed lines indicating the predictions of the mechanical glass transition temperature.
Figure 3.20 Extent of denaturation in pressurized whey (
), BSA (
), soy glycinin (
) and ovalbumin (
) systems observed using DSC (a) and FTIR (b) measurements.
Chapter 4: Crystal-Melt Phase Change of Food and Biopolymers
Figure 4.1 Schematic representation of temperature dependence of the Gibbs energy of the solid, liquid and gas phases of a substance. At the transition temperatures, the melting and the boiling temperatures (T
m
and T
b
, respectively), the Gibbs energy of the two phases are equal.
Figure 4.2 (a) Phase diagram of water (From CASTELLAN, PHYSICAL CHEMISTRY, 3
rd
Ed., ©1983. Reprinted by permission of Pearson Education, Inc., New York, NY), (b) Phase diagram for 50% gelatinization of waxy, normal, Gelose 50, and Gelose 80 maize starch slurries (10% w/w) after 5 min of processing at isothermal/isobaric conditions. Dashed lines denote conditions outside the range of measurement
Figure 4.3 Changes in thermodynamic parameters for a first order phase transition. (a) Schematic relationship between Gibbs free energy and temperature at a constant pressure; (b) the first derivatives of the Gibbs free energy with respect to temperature describing the first-order phase transitions showing a steep change at the transition temperature, and (c) the second derivatives of the Gibbs energy with respect to temperature to describe the first-order transitions.
Figure 4.4 Changes in thermodynamic parameters for a second order phase transition. (a) Schematic relationship between Gibbs energy and temperature at a constant pressure; (b) the first derivatives of the Gibbs energy with respect to temperature describing the second-order phase transitions which have the same value at the transition temperature, and (c) the second derivatives of the Gibbs free energy with respect to temperature to describe the second-order transitions showing a steep change at the transition point.
Figure 4.5 Schematic plot describing change in free energy for a homogeneous nucleation process versus nucleus radius (r).
Figure 4.6 Effect of supercooling or supersaturarion (S) on the rate of nucleation.
Figure 4.7 Schematic representation of heterogeneous nucleation of a solid from a liquid/melt. The interfacial energies, solid–surface (
), solid–liquid (
), and liquid–surface (
) are denoted by vectors.
Figure 4.8 Comparative representation of Gibbs energies for homogeneous and heterogeneous nucleation process versus the radius of nucleus (r).
Figure 4.9 (a) Avrami plot of crystalline fraction versus the time occurring in materials under constant temperature, (b) the Avrami exponent,
n
and
k
can be obtained from the logarithmic plot.
Figure 4.10 Plots of relative degree of crystallinity, α vs. crystallization time of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) containing 7 mol% 3-hydroxyhexanoate (HHx) comonomer (PHBHHx-7); isothermally crystallized at various
T
c
s for PHBHHx-7
Figure 4.11 Polarizing optical micrographs of poly(L-lactide) (PLLA), PLLA diamine copolymer (PLLA-DA), and PLLA-based dendritic L-lysine copolymer (PLLA-d) spherulites crystallized at 120, 125, 130, and 135 °C
Figure 4.12 (a) DSC heating thermograms of poly(ethylene succinate) urethane (PESU) and poly(ethylene succinate) urethane ionene (PESUIs) at a heating rate of 10 °C min
−1
from melt-quenched amorphous state, (b) DSC cooling scans, and (c) subsequent heating scans
Chapter 5: Thermal Properties of Food and Biopolymer Using Relaxation Techniques
Figure 5.1 (a) NMR T
2
relaxation and soluble protein concentration in egg white as according to temperature (Mariette, 2009, Courtesy of Elsevier), (b) Distribution of spin–spin relaxation times for Stage 1 of imitation cheese (53%, w/w, moisture) manufacture. T
2,tb
, corresponds to protons in a less mobile fraction of water within the cheese sample, correlating with water that is tightly bound; T
2,f
, ascribes to protons from the fat phase of imitation cheese and T
2,mb
, corresponds to a more mobile water fraction, correlating with water that is moderately bound (Noronha
et al.
2008, Courtesy of Elsevier), (c)
13
C solid state NMR spectra of chitosan, PU, and their graft copolymers as indicated. Digit after CHT represents the percentage of substitution (Mahanta
et al.
2015, Courtesy of the American Chemical Society), and (d) Graphical representation of spin lattice relaxation time (T
1
). The relaxation time is observed at longer time for graft copolymers against single relaxation pattern in pure CHT
Figure 5.2 The measured dielectric constants of yellow-locust honey solutions with (a) 17.4% and (b) 30.3% water contents at indicated temperatures as a function of frequency. The measured dielectric loss factors and the relaxation frequency (f
r
) of yellow locust honey solutions with (c) 17.4% and (d) 30.3% water contents at indicated temperatures as a function of frequency
Figure 5.3 Loss factor at 1 kHz in function of temperature for chitosan (a) neutralized and (b) nonneutralized: open symbols, wet samples; full symbols, annealed samples; circles, neutralized; squares, nonneutralized. Inset Figure: dielectric loss at −90 °C
Figure 5.4 (a) Thermogram of sweet potato puree based baby food (Ahmed and Ramaswamy, 2006, Courtesy of Elsevier), and (b) Differential scanning calorimetry thermograms of SPI–GA biopolymer and SPI
Figure 5.5 Dynamic mechanical responses of pure PLA and its indicated nanohybrids as a function of temperature in tensile mode (a) storage modulus, and (b) tan δ curves. The arrow indicates the position of the relaxation temperature of β-PLA
Chapter 6: Plasticizers for Biopolymer Films
Figure 6.1 Scheme for mechanism of plasticization in protein-based films.
Figure 6.2 Structure of starch polymers (a) amylose and (b) amylopectin.
Figure 6.3 Schematic representation of urea states in urea-plasticized TPS with different urea concentrations
Figure 6.4 SEM images of (a) oxidized cornstarch film and plasticized starch films with urea contents of (b) 10%, (c) 20% and (d) 35%, respectively, based on total dry weight
Figure 6.5 Chemical structure of PLA.
Figure 6.6 Effect of PEG on glass transition temperature of PLA-based film.
Figure 6.7 OTR versus sample composition
Figure 6.8 Water contact angle values for neat PLA and plasticized materials
Chapter 7: Crystallization Kinetics and Applications to Food and Biopolymers
Figure 7.1 Typical reduced crystallinity, X
t
from exotherm of palm stearin in blends with sesame seed oilobtained at isothermal conditions (Toro-Vazquez
et al.
2010).
Figure 7.2 Fitting of the Avrami model during isothermal crystallization kinetics of PLA (Cai
et al.
2011).
Figure 7.3 Non-isothermal crystallization of PLA/PEG/Ag-Cu alloy nanocomposite.
Figure 7.4 Development of relative crystallinity (X
t
) versus temperature (T) for non-isothermal melts crystallization of mica/polybutyl succinate (4/96) composite at different cooling rates.
Figure 7.5 Development of relative crystallinity (X
t
) versus time (t) for non-isothermal melts crystallization of mica/polybutyl succinate (4/96) composite at different cooling rates.
Figure 7.6
versus log (t) showing two steps mechanism (e.g., n
1
and n
2
) for PLA.
Figure 7.7 Schematic diagram of ice cream microstructure.
Figure 7.8 Schematic diagram of the ice cream manufacturing process, showing the points of addition of ingredients and the temperature profile (adapted from Clarke, 2004).
Figure 7.9 Hypothetical crystallization rate of honey samples (T
g
is glass transition temperature of honey and T is temperature of honey at any time) (adapted from Bhandari
et al.
1999).
Figure 7.10 Good and bad chocolate:Well tempered chocolate and chocolate with fat bloom characteristics (adapted from Fryer and Pinschower, 2000).
Figure 7.11 (a) A general molecular structure of triacylglycerol (R
1
, R
2
, and R
3
are individual fatty acid moieties). (b) The chemical structures of a saturated and a non-saturated fatty acid.
Figure 7.12 (a) Chain-length packing structures in TAGs, and (b) the subcell structures of the three most common polymorphs in TAGs (viewed from above the crystal planes).
Chapter 8: Thermal Transitions, Mechanical Relaxations and Microstructure of Hydrated Gluten Networks
Figure 8.1 Thermal traces of hydrated gluten at subzero temperatures using modulated differential scanning calorimetry. A broad glass transition regime is observed that spans the course of measurement (inset). Melting region is divided into a small endothermic transition of water crystalised in the nanopores followed by the major endotherm of melting of bulk ice
Figure 8.2 Microstructural model of hydrated gluten. Ice that is entrapped in the nanopores (confined water) exhibits lower melting point than that of the bulk (bulk ice)
Figure 8.3 Temperature variation of storage modulus of hydrated gluten on cooling and heating. The shaded area shows the dramatic changes of storage modulus during ice crystallization (cooling) and melting (heating)
Figure 8.4 Double logarithmic plots of stress relaxation curves between 0 and 70 °C for hydrated gluten. The influence of temperature is remarkable
Figure 8.5 Double logarithmic plots of mastercurves of stress relaxation modulus against reduced time at T
o
= 20 °C for hydrated gluten. Inset shows plots of relaxation spectra of gluten networks obtained from mastercurves using Tikhonov regularization
Figure 8.6 Generalized plot showing the development of viscoelastic functions of hydrated gluten networks over a broad temperature range. Critical region is the area where ice forms or melts and results in most dramatic changes in the stiffness of the network. At temperatures below critical region ice dominates mechanical behavior of gluten composites. Above critical temperature regime, a power-law relaxation region is observed. y-Axis values are approximate to illustrate the magnitude of the changes.
Figure 8.7 Microstructure of hydrated gluten network, (a) cryo-SEM imaging in the absence of ice-crystal growth, (b) z-stacks using confocal laser microscopy, (c) cryo-SEM imaging in the presence of ice crystals (round-etched shapes) and (d) TEM micrographs
Chapter 9: Implication of Glass Transition to Drying and Stability of Dried Foods
Figure 9.1 Effect of molecular size on glass transition temperature, T
g
, as well as onset of ice melting in maximally freeze-concentrated state, T
m
′, and glass transition of maximally freeze-concentrated solids, T
g
′, of carbohydrates.
Figure 9.2 State diagram of sucrose. The diagram is a supplemented phase diagram with data on effects of water and temperature on the state of aqueous sucrose. Equilibrium melting temperature of ice in freeze-concentrated solutions is shown by T
m
. Nonequilibrium freezing produces freeze-concentrated amorphous solutes with transitions characterized by glass transition temperature, T
g
, as well as onset of ice melting in maximally freeze-concentrated state, T
m
′, and glass transition of maximally freeze-concentrated solids, T
g
′. With permission from Roos
et al.
(1996).
Figure 9.3 Temperature and water content gradients in dehydration determine structural relaxation times, τ, which may vary from those typical of liquids to those of solids. A critical zone may be defined for optimization of drying processes or to reduce flow in storage.
Figure 9.4 WLF curve using universal values of −17.44 and 51.6 as –C
1
and C
2
, respectively with a modified WLF curve showing upwards concavity when –C
1
and C
2
are 17.44 and −51.6, respectively.
Figure 9.5 A “Food Stability Map” showing structural relaxation times decreasing with corresponding increases in relative rates of structural relaxations above glass transition. An increase in relative rates of physicochemical changes is often a result of increasing molecular mobility and thereby controlled by glass transition. The onset of glass transition corresponds to the critical a
w
.
Chapter 10: Water-Glass Transition Temperature Profile During Spray Drying of Sugar-Rich Foods
Figure 10.1 Glass Transition Temperature of Honey Increased by the Addition of Maldodextrin (Troung
et al
. 2014).
Figure 10.2 Effect of carrier type on microstructure of powder with gum Arabic (12%) (a), waxy starch (12%) (b) and maltodextrin (12%) (c) without cellulose (Yousefi
et al
. 2011).
Chapter 11: State Diagram of Foods and Its Importance to Food Stability During Storage and Processing
Figure 11.1 A typical state diagram showing four macro-regions.
Figure 11.2 State diagram showing different regions and state of foods (updated from Rahman, 2006; Rahman, 2009)
: solids-decomposition temperature,
: solids melting temperature,
: solids–glass transition temperature,
: end of solids-plasticization temperature,
: glass transition of water,
(solute crystallization temperature during freeze-concentration),
(maximal-freeze-concentration condition, that is, end point of freezing),
(glass transition of the solids matrix in the frozen sample as determined by differential scanning calorimetry (DSC)),
(intersection of the freezing curve to the glass line by maintaining the similar curvature of the freezing curve), and
(glass transition at maximal-freeze-concentration, i.e. at the end point of freezing),
: boiling temperature of water (Rahman, 2012).
Figure 11.3 Stability diagram based on the water activity concepts. gh: microbial growth trend; oa, ab, nb: chemical reaction trends below BET-monolayer; ab, nb, bc: chemical reaction trends in the adsorbed water; ce, cd, cf: chemical reaction trends in the solvent water region; ij, mj: mechanical properties trends below BET-monolayer; jk: mechanical properties trend in the adsorbed water region; kl: mechanical properties trend in the solvent water region (Rahman, 2009).
Chapter 12: Thermal Properties of Polylactides and Stereocomplex
Figure 12.1 Stereoisomers of lactic acid.
Figure 12.2 Diasteroisomeric forms of lactides.
Figure 12.3 Typical glass transition temperature for a commercial polylactide sample at a heating rate of 10 °C/min.
Figure 12.4 Effect of number average molecular weight on glass transition of polylactides at heating rate of 10 °C/min.
Figure 12.5 NMR line width-transition method for determination of T
g
of poly-D,L-lactic acid with different M
n
: solid-430; half-solid-3470; open-22730
Figure 12.6 Dynamic viscoelastic analysis for determination of T
g
of poly-D,L-lactide with Mn of 22730
Figure 12.7 Melting and crystallization curves for for neat PLLA and PDLA at heating rate of 10 °C/min.
Figure 12.8 Effect of initiators on thermal properties of PLA.
Figure 12.9 Typical melting behavior of PLA stereocomplex in two consecutive runs.
Figure 12.10 Crystallization of PLA from melt at selected temperature and time.
Figure 12.11 (a) Isothermed at 250 °C PDLA/PLLA 25/75 blend; (b) Isothermed at 235 °C PDLA/PLLA 25/75 blend; (c) Isothermed at 220 °C PDLA/PLLA 25/75 blend.
Chapter 13: Thermal Properties of Gelatin and Chitosan
Figure 13.1 Structure of chitin and chitosan
Figure 13.2 DSC thermogram of Commercial gelatin sample containing 9.3% moisture (dry basis)
Figure 13.3 Melting of 40 wt% gels formed on annealing at 20 °C for a time period of 15 to 120 min at a heating rate of 2.5 °C/min
Figure 13.4 Effect of concentration on melting of gels after annealing for 1 h at 20 °C at a heating rate of 2.5 °C/min.
Figure 13.5 Melting of 40 wt% gel obtained in 1–3 step annealing at a heating rate of 5 °C/min. Duration of each step is 30 min.
Figure 13.6 DSC thermograms (1st scan) of gelatin films without glycerol and plasticized films with 20 and 100 g glycerol/100 g protein
Figure 13.7 Typical TGA curve of gelatin/water system for a temperature range from 0 to 450 °C: determination of total water, bound water and free water
Figure 13.8 DSC thermograms of pure chitosan
Figure 13.9 DSC thermogram of chitosan
Figure 13.10 DSC curve of (a) chitin–chitosan and (b) N-benzyl chitosan
Figure 13.11 TG and DSC thermogram of chitosan at heating rate of 5 °C/min
Figure 13.12 DSC thermogram of chitosan at various heating rate
Chapter 14: Protein Characterization by Thermal Property Measurement
Figure 14.1 General representation of DSC instrumentation for the thermal property measurement. R = reference cell, S = sample cell, T = temperature, ΔT = Temperature difference between the reference and sample cells, and C
P
= heat capacity of sample/protein.
Figure 14.2 General representations of DSC curve for any proteins without any permanent change in the heat capacity. T
m
- maximum peak transition temperature, ΔT
1/2
= width of the transition at half maximum peak temperature, ΔH
cal
- calorimetric enthalpy value, which is equals to the area under the curve, and ΔC
P
- the change in the heat capacity of a protein.
Figure 14.3 Permanent changes in the specific heat capacity of a protein/polymer after thermal transition.
Figure 14.4 Calculation of specific heat capacity from the enthalpy versus maximum peak transition temperature curve. The enthalpy value is calculated experimentally by summing up the area under the curve for each run. t
Mi
= maximum peak transition temperature for a protein for the run “i” and ΔH
i
(t
Mi
) is the change in the enthalpy as a function of heat capacity.
Figure 14.5 Intramolecular incorporation of different domains of a protein unfold independently.
Figure 14.6 Sequential unfolding of a protein through a serious of intermediate steps.
Figure 14.7 Isothermal calorimetric analysis of macromolecule and ligand interaction in a single and dual reaction chamber. The typical output of a calorimeter and its interpretation to find the thermodynamic parameters and binding constant. R = reference chamber/cell, S = sample/reaction chamber, ΔH
b
-molar enthalpy of binding (µcal/mol), k
b
- binding constant (M
−1
), k
d
- disassociation constant (M), and ΔT = temperature difference between the reference and reaction cell, which is maintained as zero throughout the reaction.
Figure 14.8 Illustration of protein unfolding that expose the hydrophobic surface area bound fluorescent dye during heating followed by an aggregation of protein. The assay is carried out in multi-well plate in Real-time PCR instrument and fluorescent signals are measured by a high resolution camera send the signal to computer or data processor. T
M
= maximum transition temperature, in which the hydrophobic patches bound fluorescent dye are exposed to the surface of the protein. The dark and white circles represents the hydrophobic surface exposed protein and unexposed (hydrophilic surface covered) forms of proteins.
Chapter 15: High-Pressure Water-Ice Transitions in Aqueous and Food Systems
Figure 15.1 Phase diagram of water under pressure (Bridgman, 1912) and its application possibilities for high-pressure processing of foods. (1) pressure-assisted freezing (ABCD), (2) pressure-assisted thawing (DCBA), (3) subzero storage without freezing (ABEF), (4) pressure shift freezing (ABEFG), (5) pressure-induced thawing (GFEBA), (6) freezing to ice III (ABEFH), (7) thawing of ice III (HFEBA), (8) freezing above 0 °C to ice VI (ABEJ). Pressure-assisted means phase transition under constant pressure, pressure-shift means phase transition due to pressure change, and pressure-induced means phase transition initiated with pressure change and then continued at constant pressure (based on Knorr
et al.
1998; Le-Bail
et al.
2002a).
Figure 15.2 Schematic description of the HPF system (based on Su
et al.
2014a).
Figure 15.3 A typical pressure shift freezing curve (based on Su
et al.
2014a).
Figure 15.4 High pressure assisted freezing processes (PAF) producing different ice polymorphs: ice I (ABCDE) or ice III (A'B'C'D'E') (picture based on Otero & Sanz, 2014).
Figure 15.5 Working procedures of HPT based on water-ice phase diagram of Bridgman (1912).
Figure 15.6 Changes in sample temperature and medium pressure during the different stages of high pressure thawing process for a pure water sample.
Figure 15.7 Experimental setup of HP differential scanning calorimeter: (a) schematic diagram, (b) photograph of the calorimetric head and the cells (courtesy, Zhu
et al.
2004c).
Figure 15.8 A typical measurement of isothermal pressure scan (0.3 MPa min
−1
) of pure ice (0.5712 g) with calorimetric temperature at −10 °C (Zhu
et al.
2004c).
Figure 15.9 Temperature scan of pure ice at 0.1 and 115 MPa: (a) thawing heat flow rate, and (b) thawing latent heat (Courtesy, Zhu
et al.
2004c).
Chapter 16: Pasting Properties of Starch: Effect of Particle Size, Hydrocolloids and High Pressure
Figure 16.1 RVA (left) and VAG (right) pasting curve for starch dispersion (
Source
: Perten & Brabender).
Figure 16.2 Rheometric measurement of pasting properties of rice starch (10%) dispersion.
Figure 16.7 Evolution of complex viscosity following viscoamylographic time-temperature profile on chestnut doughs prepared from freeze and tray drying process. a. microviscoamylograph measurement and b. Oscillatory rheometric measurement.
Figure 16.3 Pasting profile and its first derivative of amylopectin and amylose rich corn starch with selected point of study (Rincón-Londoño
et al.
2016).
Figure 16.5 SEM images of the morphological changes for region I (points 1–5) for the pasting profile of amylopectin (left) and region I (points 1–3) for amylose (right) (Rincón-Londoño
et al.
2016).
Figure 16.4 SEM images of the morphological changes for region II (points 6 and 7) and Region III (points 8 and 9) for pasting profile of amylopectin and for region II (points 4 and 5) and region III (points 6 and 7) for amylose. (Rincón-Londoño
et al.
2016).
Figure 16.6 Effect of xanthan gum concentration on pasting profile of β-glucan enriched brown flour dough.
Figure 16.8 Pasting profiles of high-pressure treated lentil starch samples.