Food structure and Propierties - INFOGEST, 2013

UMR1145 Ingénierie Procédés Aliments
A MULTI-SCALE APPROACH FOR COUPLING FOOD
STRUCTURE AND PROPERTIES
Dr. Jean-Baptiste BOITTE – jean-baptiste.boitte@cad-inst.com
Research & Development Manager – CAD Instruments – France
Pr. Camille MICHON – camille.michon@agroparistech.fr
Professor – JRU Food Process and Engineering – AgroParisTech – France
1
INFOGEST COST Action 2013 – Gdansk, Poland
22 – 26 April, 2013

Cliquez pour modifier le style du titre
2
Complex (food) systems – a worldwide interest
2
Process Complexity
SystemComplexity
-
-
+
+
Structureandcomposition
Thermo-mechanical treatment
IATE
(Montpellier)
Wageningen
SIK
ETH
GEPEA
(Nantes)
Birmingham
York
Weihenstephan
Reading
Leeds
Canberra
BIA-Nantes
Guelph
Cork
Wrexham
Univ.
Maine
Osaka
Laval
LGPTA
(Villeneuve d’Ascq)
IFR
Queensland
NIZO
WUR
PUC Chili
Massa.
Univ
Technion
VTT
STLORennes
Univ.
Bordeaux
Univ.
Paris XI

Outline of the presentation
3
1. Food complexity
> What do we call “structure of food product”?
> Composition and structure: what is the link?
> Building as a multi-scale approach
2. Food systems basic properties
> Properties from continuous phase
> Dispersed phase and stabilization
> Mixtures and interactions
3. Structures at different scales: effects of the process and/or
composition
> Bread
> Dairy foam stabilized by Gelatin or HPC
4. Tools for coupling structure and properties: some examples

4
1. Food complexity
composition
> Bread

Food products: complex structured materials
5
Mayonnaise: a simple emulsion?

6
(Food Emulsion, Larsson et Friberg, 1990)

7

8
Dairy products
Fat globules
(triglycérides)
Caseins micelles
10 - 200 nm
Several µm
serum: proteins, lactose, …
Milk A
B
C
x 5
Uniform and turbid system
=> inhomogeneous
x 500
x 50 000
(From Mulder and Walstra, 1974)

9
PhD E. Gastaldi, Montpellier, 1994
Milk acidification leads to a curd
yoghurt
Dairy products

10
Chantilly cream
Dairy products

11
Chantilly cream
Dairy products
(Anderson et Brooker in Food Emulsions and foams, Dickinson & Stainsby, 1988)

12
Chantilly cream
Dairy products
(Anderson et Brooker in Food Emulsions and foams, Dickinson & Stainsby, 1988)

13
From wheat flour to bread dough and … to bread
Starch based products

14
From wheat flour to bread dough
Starch granules in a proteic matrix = a flour grain
SEM of bread dough at 47% w/w in water
(Létang et al., 1999)

15
Attenburrow et al., 1989
Properties of solid foam products
Rigidity (firmness) vs. density

Complexity
16

Relationship between composition and structure
17
Pyramid of 4 principal components
(Aguilera et Stanley, 1999)
Composition gives only
a partial information on the structure

Relationship between composition and structure
18
(Aguilera et Stanley, 1999)
Texture
Potential structural parameters:
• Rheological behavior (viscosity, hardness/stiffness, …)
• Others physical properties (aw, FC, WC, …)
Composition of food products represents a potential
of structuring but not enough to characterize this
structure:
• Techno-functionnal properties of ingredients
+
• Process (thermo-mechanical treatment)

Different observation scales of constitutive elements
19
Microscopy
techniques
SOURCE
Vegetal
(Meat)
Animal
(Milk)
1Å 1nm 10nm 100nm 10µm1µm 100µm 1mm
Transmission electronic microscopy
Scanning electronic microscopy
Optical microscopy
eau
ions
lactose b-lg Sub-
micelles
Caseins
Micelles Fat
globules
Size
myosin
Collagen’s fibers
Fibrils Fibers
membranes
Stocked
Lipids
Stocked
Proteins
Cells wall
Starch
granule
Cell
Particles
(from Aguilera et Stanley, 1999)

Complexity of food: example of bread baking
20
C-C
Links
Starch granuleglutenin pericarpe
fragment
breadglutenin filament
10-10 m
0,1nm
10-9 m
1nm
10-7 m
100 nm
10-6 m
1µm
10-8 m
10 nm
10-3 m
1mm
10-2 m
1 cm
10-5 m
10µm
10-4 m
100µm
10-1 m
10 cm
alveolegluten filmamylase

Starch structures and characterization at different scales
21
(Condé-Petit, 2003)

Evolution of a food product during processes
22
Finished
Product
Native
Structure
Built
Structure
Structuring
Processes
• Heat
• Mass transfer
• Shearing/Deformation
Product
Characteristics
Modification of the structure at different scales:
• Molecular
• Micro-structural
• Macro-structural
Engineering of the structure:
• Contribution to new products
• Transformation of the structure under control
• Mixing constituents + combination => creation of the product
New tools for technologist
to measure properties (mechanical, thermal, chemical,….)
and at the 3 structural scales
Components
of food
• Proteins
• Lipids
• Sugars
• Water
Raw materials,
Ingredients

23
De-structuring
Final
Product
Final
Structure
Distribution
Stocking
• T
• W
• t
Product
quality
Not always
controlled!
Ideally, engineering of the structure
can predict a mechanism of
post-structuring which allows
preserving structure (i.e. good resistance to
variations of conservation conditions)
or achieving the construction
of the structure
Finished
Product
Native
Structure
Built
Structure
Structuring
Processes
• Heat
• Mass transfer
Product
Characteristics
Components
of food
• Proteins
• Lipids
• Sugars
• Water
Raw materials,
Ingredients

24
Food
Product
Sense
Structure
Chewing
Consumption
Intake
Product
evaluation
Importance of sensory science !!
De-structuring
Final
Product
Final
Structure
Distribution
Stocking
• T
• W
• t
Product
quality
Not always
controlled!
Finished
Product
Native
Structure
Built
Structure
Structuring
Processes
• Heat
• Mass transfer
Product
Characteristics
Components
of food
• Proteins
• Lipids
• Sugars
• Water
Raw materials,
Ingredients

Reverse engineering notion
25
Destructuring
Final
product
Structuring
Wished
Final
Texture
?
Reverse engineering
Processes
• Heat
• Mass transfer
Product
Characteristics
Components
of food
• Proteins
• Lipids
• Sugars
• Water
Raw materials,
Ingredients
Knowledge and understanding on structuring

Where are we in terms of knowledge on food structuring?
26
Knowledge on model medium
Functional properties of ingredients individually considered
Interactions of pair ingredients
….
Knowledge of process effects
Temperature effect
Shear/Deformation effect
….
Opportunity to observe final organization of food composite
material at different scales
… far away from a complete control of
food structuring because links between
above mentioned knowledge are missing

27
1. Food complexity
composition
> Bread

Examples of structured systems
28
Suspensions
Emulsions
Foams (liquids, deformable solids or solids)
Thickening liquids
Gels
Paste materials
Composites materials (elastic or solid)

Macromolecules Solvent
Structure
Molecular Weight
pH
ions, ionic strength
temperature
M/S
C
entanglements
M/M
MATRIX
STRUCTURING
« Connection zones »
Structuring using biopolymers
29

Thickening mechanism
macromolecules / solvent
« hydrodynamic volume » important
viscosity
Thickening agent in solution
30

31
(Cuvelier et Launay, 1986)
25°C // 0.1 M NaCl
Example: flow curves = ( ) – xanthan solutions

C < C*
dilute regime
C = C*
critical concentration
C > C*
semi-dilute regime
« entanglements »
Macromolecular solutions: concentration effect
(from De Gennes, 1979)
32

33
25°C // 0.1 M NaCl
Example: flow curves = ( ) – xanthan solutions

Xanthan 0.25%
Locust bean gum 0.5%
Locust bean gum 0.25%
T = 25°C
Flow properties of 2 thickening agents
34

Gelation mechanism
Sol – Gel transition and gels’ evolution
Gel state
Liquid, viscoelastic
Sol state
Random
Junction zones
sol-gel transition
Solid, viscoélastic
Water expulsion?
Network contraction
Junction zones
reticulation
rigidity
concentration,
temperature,
time
gelation critical parameters
35

Gelation mechanism
3D macromolecular network
Viscoelastic properties with:
- low modulus
+/- weak
Time dependance
Reversibility? thermal
mechanic: thixotropy
Based-biopolymers gels are « physic » gels
Structured by low energy bounds on a sufficient
lenght: junction zones
Junction zones
36

Gelation mechanism
Long chains association
Dense objects aggregation
37
Mixtures
ιιιι-carrageenan
κκκκ-carrageenan
alginates

Dispersed objects
Cream or sauces with
« low » fat content
Rheology: major contribution
of the continuous phase
38

Dispersed objects - Stabilization
Emulsion processing
2 non-miscible liquid phases
Energy
Dispersion of Phase 1, as droplets, in Phase 2
Non-miscibility
Interfacial energy (mJ.m-2)
Work to provide to create interfaces
Example:
• 30 mL oil and 70 mL water => interface of several cm²
• In an emulsion, with 1 µm diameter droplets => interface of 90 m² for 7.1012
droplets…!
For stabilizing an interface => decrease the surface
tension by means of surfactants
39

Interfaces stabilization
Surfactant
Amphiphilic compound: hydrophobic and hydrophilic pole (anionic,
cationic, non-charged) with a same molecular structure
Adsorption at oil-water interface
Compound which
decreases the interfacial
tension = emulsifier
Hydrophilic pole
Hydrophobic pole
40

Some surfactants
Cellulose derivative
41

Droplet: Volume or surface controlled
HPC solution
Concentration: 0.01 g/l
Volume: 10 µL
42

Surface tension vs. concentration
HPC solution
Concentration: 0.01 g/l
Volume: 10 µL
43

Connecting dispersed objects
Depletion – Floculation
44

+ xanthan
45
Depletion – Floculation

« high » fat content
Rheology: contribution of
both continuous phase and
disperse phase
46

47

48

49
« high » fat content
Rheology: contribution of
both continuous phase and
disperse phase

P1 / S
C
System homopolymer
SP1
What happens for a mixed system? P1 / P2 / S
50
Mixtures - Interactions

Respective affinity between P1 and P2
example: 2 ionic polymers with opposite charge
Low affinity of P1 and P2 for the solvent
SP1
S
P2
Associative interactions
« Complex coacervation »
« Associative phase separation »
51

52
Phase rich in P2 and P3 Phase with solvent as major component
S 1
P 2 P 3
a
b
P3
a b
Example: polyelectrolytes with overall opposite charge

53
Example: polyelectrolytes with overall opposite charge
b
a
P2
P3
b
a
Culot
Surnageant

S
P1
SP2
P1
P2
S
P1
P2
Diluted C
P1 and P2: no reciprocal affinity
P1 and P2: non-similar affinity for the solvent
examples:
- 2 ionic polymers with the same charge
- 1 ionic polymer / 1 non-ionic polymer
54
Segregative interactions
« Thermo-dynamic incompatibility »
« Segregative phase separation »

Example: non-ionic polymers, ionic polymer / non-ionic polymers, ionic polymers
with the same overall charge
55
S 1
P 2 P 3P3
a b c
a b c
Phase rich in P2 and P3 Phase with solvent as major component

56
P2
P3
a
b
c
Surnageant
Culot
c
a
b

75% locust bean gum continuous phase
25% SMP included phase
25% locust bean gum included phase
75% SMP continuous phase
Bi- continuous system
(50/50 % phase volume)
50403020100
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Skimmed Milk Powder %
LocustBeanGum%Phase diagram:
Milk / Locust bean gum / Saccharose (20%)
5°C
(From Schorsch et al., 1999)
57

58
1. Food complexity
composition
> Bread

Liégeois Bread
59
Context - Motivations

Context - Motivations
Foam Bread
OPTIC
MICROSCOPY
CAMÉRA
TEM/SEM
CONFOCAL
SAXS/WAXS
DLS
mm
µm
nm
60

61
1. Food complexity
composition
> Bread

Bread: structures at all scales
Baking
Ingredients Bread
Kneading
Shaping
Dough
Composition
Growing
Flour, water, salt, yeast
(saccharose, oil)
Crumb
structure
Sensory Properties
Instrumental
Characterization
Rheological Properties of the
Dough (Lassoued, 2005)
62

(Roussel et Chiron, 2002)
Effect of mixing intensity on microstructure of bread dough
Electronic Microscopy (photo INRA)
Conventional mixing Intensified mixing
Process effect on bread dough structuring
63

(Roussel et Chiron, 2002)
1. No-shaping after cutting
2. Manual shaping
3. Mechanical shaping
1
2
3
Effect of shaping mode on crumb
64

65(from Lassoued, 2005)
Small deformations:
ηηηηapp when [Water] and [Saccharose]
Large deformations:
Strain-hardening behavior?
[Water] 60%
[Saccharose] 7%
1.104
2.104
3.104
4.104
5.104
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
60% W
55% W
50 % W
ApparentViscosity(Pa.s)
Biaxial Strain εεεεb
1-s0.05ε =ɺ

(Lassoued, 2005)
Dough Microstructures
60%
[Water]
55%50%
?
Small déformations
ηηηηapp ↑ when [Water] and [Saccharose] ↓
Large déformations
Strain-hardening behavior?
Kneading / Shaping Growing / Baking
66

Observation of wheat flour doughs under
thermo-mechanical treatments
67
(Boitte et al., J. of Cereal Sci., submitted)

Observation under thermo-mechanical treatments
Observation under thermal treatment
Thermal control?
Images acquisition?
Interesting compound evolution?
Operating condition
Bread dough enriched
with rapeseed oil (5%)
T = 45°C (fast ramp)
Lipids
Proteins (gluten)
Co-localization
50 µm
68

How behave bread dough under shearing?
Localization of interesting compounds?
Local variation or evolution along shearing time?
• Bubbles?
• Co-localization level?
Lipids
Proteins (gluten)
Co-localisation
t = 6.7 st = 2.2 st = 1.7 s t = 5.8 s
69
Observation of under thermo-mechanical treatments

Greyscale mathematical morphology
► Module GranuloMorpho1, MATLAB (The MATHWORKS, USA)
Dilatation Erosion
Grey level images
V0
i=1 // V1
i=n // Vf
i=5 // V5
(1 Devaux et al., 1997, 2008)
70

Greyscale mathematical morphology
Linear pattern: r = 1 pixel, θ = 45° or 135°
30 successives steps erosion-dilatation = grey level mean
Variation of grey level mean (gi)
71

-8 -6 -4 -2 0 2 4 6
-4
-2
0
2
4
(1-4 s) (28-31 s)
T
E+
E-
S+
S++
Local protein concentration in the gluten fibers
77.5%
Orientation level of
the gluten network
21.1%
- +
-
+
Axe 1 (77.5%)
72

Baking
Ingredients Bread
Kneading
Shaping
Dough
Composition
Growing
Flour, water, salt, yeast
(saccharose, oil)
Crumb
structure
Sensory Properties
Instrumental
Characterization
Rheological Properties of the
Dough (Lassoued, 2005)
Correlations
73

74
1. Food complexity
composition
> Bread

Foaming process
Food base
Gas
Foam
Double wall for
thermostating
Structuring by shearing…
75

Foaming process
Understanding the physical parameters influencing the foaming
process
Parameters:
Foaming process: shear rate, temperature, pressure
Food base: viscosity, tensio-activity, shearing sensitivity
76
Foam stability
Foaming deviceGas + Liquid Foam
Shearing (rupture + coalescence)
Bubbles generation

Foaming process - Gelatin
Bubble generation on gelatin solutions
77
SDS
CTAB
Eau
Concentration (% w/w)+ -
10-1 10-2 10-3 10-510-4100
Gelatin 1040
Gelatin 1039

V=f(C)
2
4
6
8
10
12
14
16
18
C (g/100mL)
V(mm3)
CTAB
1039
1040
SDS
Water
10-5 10-4 10-3 10-2 10-1 100 101
10-7 10-610-8
?
78
Bubble generation on gelatin solutions

Cliquez pour modifier le style du titreGelatin droplet relaxation
Influence of the concentration
⇒ C ↑: round shape at the extremities
⇒ Low C: very thin strands appears. Possible breaking at large deformation
Water
79

Continuous phase properties
Effect of mechanical treatment – restructuration
80

81
Ω ↑↑↑↑ ⇒⇒⇒⇒ G’ ↓↓↓↓
Continuous phase properties
Effect of mechanical treatment – restructuration
300 rpm
600 rpm
1500 rpm

Foam properties
Influence of rotation speed on the bubble size
Foaming rate 100% (∅gas= 0.5) – Flow rate: 4 L.h-1
82
0
5
10
15
20
0 20 40 60 80 100 120 140 160 180 200
Nombredebulles(%)
Diamètre des bulles (µm)
0
5
10
15
0 20 40 60 80 100 120 140 160 180 200
Nombredebulles(%))
0
5
10
15
20
25
0 20 40 60 80 100 120 140 160 180 200
Nombredebulles(%)
300 rpm
600 rpm
1500 rpm

Cliquez pour modifier le style du titreFoam properties
Influence of rotation speed on the bubble size
Foaming rate 100% (∅gas= 0.5) – Flow rate: 4 L.h-1
83

Cliquez pour modifier le style du titreFoam’s evolution
Evolution of the continuous phase?
Evolution of the foam structure? ⇒ ripening
t0 + 1h
t0
t0 + 7h
84

Cliquez pour modifier le style du titreFoam’s evolution
Ripening limiting?
Gas mix: nitrogen + PFH
85
t0 + 1h
t0
t0 + 7h
Nitrogen Nitrogen + PFH

Cliquez pour modifier le style du titreHPC: a cellulose derivative
HydroxyPropyl Cellulose = surfactant
from Coton
HPC used for Chantilly
30% fat cream foaming
Chantilly: a foaming process - HPC
86
Hydrophobic
zones
With HPCWithout HPC
(Michon et al., 2006)
24% fat cream foaming

Foaming process - HPC
Adsorption kinetics of HPC
Air-Water interface
Oscillatory drop technic: surface rheological properties
87
(Mezdour et al., 2007a and 2007b)

Cliquez pour modifier le style du titreAdsorption kinetics of HPC
Oil-Water interface
Oscillatory drop technic: surface rheological properties
88
(Mezdour et al., 2008)

HPC + Milk
Presence of casein and fat globule
89
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12
Casein micelles (wt%)
HPC (wt%)

HPC (wt%)
Incompatible
Compatible
0.12 wt%
Dairy
Cream
Protein
content
How can we explain that 0.12 wt% HPC in cream
leads to a stable system?
Interactions (very) complex systems…
90

Cliquez pour modifier le style du titreMicrostructure of dairy cream with 0.12% HPC
Alexa: protein Bodipy: fat globules
40 µm
40 µm
91

Cliquez pour modifier le style du titreMicrostructure of dairy cream with 0.12% HPC
Alexa: protein Bodipy: fat globules
40 µm
40 µm
92
40 µm

Casein micelles
(0.2-0.3 mm)
HPC
Carrageenan
Emulsifier
Fat droplet (2-3 mm)
40 µm
Local organization of a dairy cream with HPC
93

Zones
Hydrophob
es
HPC
Segregative phase separation
40 µm
Microstructure 31% fat cream
Complex continuous phase study
protein/fat co-localisation
(Hamaty et al., 2005; Erazo-Majewicz et al., 2005)
With HPCWithout HPC
24% fat
cream foaming
(Michon et al., 2006) (Mezdour et al., 2007, 2008)
εεεε’/mN.m-1
0
10
20
30
40
50
0 5 10 15 20
HPC
Phase 1 Phase 2
Oil/water interface
ΠΠΠΠ/mN.m-1
Time /s
Air/water interface
Hydrophobic
zones
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12
HPC (wt%)
94
Macroscopic
Surface Rheological - Molecular
Phase Diagram - Mesoscopic

95
1. Food complexity
composition
> Bread

Tools for coupling structure and properties
Rheo-Optic: 2 possibles strategies
96
Rheology = Properties Observation = Structure
OPTICAL
MICROSCOPY
CAMERA
TEM/SEM
CONFOCAL
SAXS/WAXS
DLS
mm
µm
nm
Taylor, 1932
Birkhofer et al., 2005
Wu et al., 2007
Baravian et al., 2001
Nicolas et Paques, 2003
Besseling et al., 2009

97
(Linkam)
(Wu et al.)
(Taylor)
(Levitt et al.)
(Mighri)

Rheometer - Confocal
98
(Besseling et al.)
(Nicolas and Paques)
(TU Eindhoven)

99
RHEOPTICAD
A THERMO-MECHANICAL DEVICE FOR CLSM
(Boitte et al., Rev. Sci. Instruments, 84, 2013)

RheOptiCAD – A Thermo-Mechanical Device for CLSM
100
Bottom plate
Top Plate
► Suction system for holding the glasses
► Easy, fast and reproducible samplig

101
Observation using a CLSM
t
CLSM
CLSM
x
y
z
Movies
Built image
Plan focal
Several
focal planes
3D
V
V
t

Balance optic – mechanic
130 images
400 µm, 0.3 Hz
Focal Plane
CLSM
t
Movies
512 x 256 pixels
13 images per period
102

RheOptiCAD - Microgel + probes1
103
Position of ZVP ?
Additional questions
Acquisition
Profile reconstitution ZVP
Vinf
Vsup
zZVP = 132 µm zZVP = 57 µm
500 µm
zZVP = 250 µm
x
z
CLSM
(1 Bonnecaze et Cloître, 2010)
100 µm.s-1
100 µm.s-1
400 µm.s-1
51 µm.s-1
200 µm.s-1
72 µm.s-1

RheOptiCAD - Carrageenan + probes
104
Characterization of flow properties?
Wall slips?
Gelation under shearing?
0.02 s-1 0.075 s-1 0.1 s-1 0.2 s-1 0.3 s-10.05 s-1
Gelation line
Top plate
Bottom plate
T = 45°C
T = 20°C
- 5°C.min-1
300 µm
Acquisition
150 images in t=33.5 s
Cooling under shearing

Formation and observation of bubbles
105
LED
Webcam
Etuve
LED
Glass tube
Programmable
syringe

Formation and observation of bubbles
106
Pure Water
V ≈ 17 µL
Using a fast CCD
(1000 fps)

Surface Rheology Analysis
107

Counter-rotating observation device
108
Counter-rotating device for studying droplet relaxation
⇒ Image analysis: deformation = f (t)

109
To create texture structure texture
To facilitate the use
manipulation, transport, implementation, consumption
To allow a post operation
To stabilize
physical / physico-chemical / biological stability
facilitate or prevent transfer / prevent, protect for bioavailability
control release of aroma, nutrients, constituents…
Intermediate products
texture agents = “structure agents”
products “ready to structure”
Structuring: what for?

Which product? What types of structure?
110
Most of the food products are concerned!!
always multiphasic systems
•heterogeneous (scale?), assembly, multi-layers, …
Which structure?
molecular organization
(complexation / microencapsulation)
macromolecular solutions / gels
emulsions / foams – air-based systems
particles suspensions
! Most of the times: combination of structures
What are macroscopic properties?
liquid
“semi-liquid” (yield stress fluid), paste/dough, …
+/- deformable solid, rigid, fragile, cohesive, …..
complex
rheology!

Which product? What types of structure?
111
What kind of structure? What level?
nature and properties of the continuous phase
nature and properties of the dispersed elements
organization and properties of interfaces
organization of dispersed elements
Functional ingredients
Polyosides – proteins - surfactants
Influence of thermal, mechanical treatments, conditions of the medium
Interactions:
• Associative?
• Segregative?
Transition phenomenon and phase diagrams
sol-gel transition
crystallization phenomenon
glassy transition

112
Thanks for your attention
Questions, discussion?...
jean-baptiste.boitte@cad-inst.com
camille.michon@agroparistech.fr

Food structure and Propierties - INFOGEST, 2013

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