Limagrain Céréales Ingrédients
Raw material Choices for
Extruded Snacks
Ingredients for extruded snacks - agenda
Cereals and root crops
Raw material
Expansion
Flavor
Color
Corn/Maize
good
strong
yellow
Rice
good
bland
white
Wheat
fair to good
mild
off-white
Barley
fair
strong
light brown to gold
Oats
poor
strong
light brown
Potato
good
strong
gold to light
Tapioca-Manioc
good
bland
white
 Extrusion processing aids : water, fats and emulsifiers, fibre, starch, sugars, salt
Frying Oils
Flavors and seasonings
Main components: starch, proteins, fibre, lipids, salt, sugars
Focus on Starch
Starch
Amylose: linear
20 to 30% ,
up to 70% in High-amylose
Amylopectin: ramified
70 to 80% ,
up to 100% in waxy
Starch changes in extrusion
Starch GELATINIZATION : in presence of water and heating during extrusion
 Loss of organization of starch granules



Swelling
Disruption
Release of molecular components
 Changes in viscosity


Increases to maximum value => swollen granules
Decrease of viscosity => granules disruption
 Impact of other factors


Shear: enhance granule disruption and even depolymerization
Other ingredients (fats, proteins, salt): affect starch gelatinization
Normal
starch
Waxy
starch
Starch changes in extrusion
Starch RETROGRADATION : during & after extrusion, baking, frying
 Opposite of gelatinization
 Reassociation of polymers
Waxy starch, rich in amylopectin =>
low retrogradation compared to normal starch
 Retrogradation affects the structure and texture of snacks
Normal
starch
Waxy
starch
Starch ingredients : focus on maize
Maize grits range
Flaking grits: 3350 - 5600 µm
Cereal grits: 2000 - 3350 µm
Coarse grits: 800 - 2000 µm
Medium grits: 500 - 1500 µm
Fine grits: 250 - 500 µm
Maize Flours: < 250 µm
=
F (Raw Materials, Process, Agronomical)
Maize Variety
In Europe:
-400 varieties registered
-100 varieties grown
Cooking characteristics of maize ingredients
Endosperm character
FP = Floury Part (soft)
HP = Horny Part
HP
HP FP
HP
FP
Maize types
Dent
Dent-flint
Flint
Texture / Hardness (cooking ability)
Soft
From soft to hard
Hard
FP
Impact of particle size :
Impact of maize hardness :
Coarser particles => slower hydration and
viscosity development than fine particles
Harder variety => limited starch swelling &
slower hydration and viscosity development
100
90
80
70
60
50
40
30
20
10
0
6000
Viscosity
5000
4000
3000
2000
1000
0
0
200
400
time
600
800
4500
100
4000
90
3500
80
70
3000
Viscosity
7000
60
2500
50
2000
40
1500
30
1000
20
500
10
0
0
0
200
400
time
600
800
Speciality starchy ingredients for extrusion
Use at low levels: up to 10% to improve quality and
process
 Speciality
flours: pregel & waxy
flours
For optimal behavior in extrusion: controlled precooking level
et particle size
Improvement and control of expansion
Compensate expansion decrease resulted by adding fibres,
whole grains, proteins
Play with texture (light, crispy to crunchy bite)
Clean label: declared as “ flours”
 Speciality
starches :
Native, physically modified (pregel) or chemically modified
Waxy starch : light texture, greater expansion
High-amylose starch : firmer texture ,decreases oil absorption,
increases of TDF
Focus on Protein
IMPACT OF PROTEINS

Second major constituent after starch in cereals
Rice- 6%, Maize- 7%, Wheat -12%, Beans-21%, Lentils - 23%



Made up of amino-acids: essential and non-essential
Role in palatability and nutrition
Impact on texture and flavor of extruded snacks
PROTEINS CHANGES IN EXTRUSION
Bind water and compete with starch
Inhibit starch swelling
Denature during process, loose water

protein denatures at 60-70°C : become insoluble

starch gelatinize at 51-78°C: become soluble
Re-associate with starch and form a continuous phase
17/06/2013
Adding protein to snacks :
-Less EXPANSION
-Harder, more crunchy TEXTURE
-More irregular SHAPE
-Impact on FLAVOUR
Focus on Fibres
CODEX DEFINITION
Fibres
 Fibres: carbohydrate polymers which are not hydrolyzed by
the endogenous enzymes in the small intestine of humans


Insoluble : celluloses, lignin
Soluble : beta-glucans, pectin, gums
IMPACT OF FIBRES IN EXTRUSION
 Nucleation agents
 Micronized fibres create a fine structure
 Reduction of EXPANSION, depending on :
 Origin of fibres



pea , soy , beet , fruit fibres
wheat & corn bran
oat & rice bran
=> the lowest reduction
=> moderate reduction
=> high reduction
 Particle size : expansion increase with decrease of particle size
 Composition : better expansion for pure fibres (low in lipids and protein)
Fibres in snacks - examples
80
Impact of fibre on snacks: output and bulk density
70
60
100% 36.05X
50
36.05X
40
36.05X + F184.80 (2,5%)
30
REFERENCE
Allegations
36.05X + F184.80 (5%)
20
10
0
Output (kg/h)
35
100% 36.05X
+ 2.5% fibre
Density (g/l)
« Rich in fibre »:
6% of TDF on final
product
Impact of fibre on snacks: lenght and diameter
30
25
20
36.05X
15
36.05X + F184.80 (2,5%)
36.05X + F184.80 (5%)
10
5
0
Lenght (mm)
Diameter (mm)
« Source of fibre »:
3% of TDF on final
Product
100% 36.05X
+ 5% fibre
Whole grains
MAIN CHALLENGES IN EXTRUSION
 Higher fat content: Less expansion
 Higher fibre content impact :
 Texture and structure
 If finely ground
=>smaller cells, fine structure
 If coarsely ground =>reduced expansion
 Color: generally darker
 Taste: bitterness
 Sourcing
 Related to mycotoxins, freshness of the material
(rancidity )
Whole Grains
ADVANTAGES OD PRECOOKED WHOLE GRAINS FLOURS
 Stability & Shelf-life
 Precooked starch granules (partially to full) &
denatured proteins develop functionalities:
control of expansion and structure
 Controlled particle size and precooking level:
consistency in extrusion process
 Bran fraction finely ground : fine structure of
extruded snack
 Reduction of bitterness
 Clean Label and authenticity
Impact of oil and fats
 Lipid content depend on raw materials used
 Oat (7%), maize grits (<1%)
 Lipids coat particles and interfere with moisture
penetration
 more difficult to cook and expand
 Extrusion inactivates the lipase activity and stop
hydrolytic rancidity but can increase the
oxidative rancidity
 Oils and fats added in formulations as
processing aids at 0,5-1%
 Act as lubricant & reduce mechanical energy
Salt in extruded snacks
 Key ingredient in salty snack seasoning
 Levels : in extrusion formulations (1-1,5%);
in seasoning blend (15-30%)
 Types of salt : sea salt, flour salt
 Functionality
 Potentate overall flavor of seasoning
 Masks flavors: decreases perception of metallic
and bitter flavors
 Aroma: at high concentration can reduce aroma
 in some cases acts as extrusion process
regulator
Reducing salt in snacks
Salt replacers:
KCl : salty taste but also bitter or metallic aftertaste
Salt enhancers :
 Amino-acids, glutamates, yeasts, organic acids
Increase of salt efficiency
 Crystal form, sea salt, particle distribution
Reducing salt added during extrusion=>
sometimes process problems
 Correct by using pregel flours or speciality
starches
Development of new extruded snacks
Authenticity, wellness, new experiences,…
...many snack development drivers!
But pleasure remains king!
Final product
Semi finished product
=
Raw Materials
+
Process
Moisture
Moisture
Formula
Size, Shape, bulk density
Particle size
Throughput
Nutritional properties
Flowability
Thermally energy input
Surface aspect
Content in starch,
Mechanical energy input
Texture, Structure
lipids, fibres, proteins
Retention time
Taste, Flavor
Color
Die geometry…
Thanks for your attention