Lecture 9. Pre-treatment of feed sources
and
Lecture 10. Extrusion and nutritive value
Olav Fjeld Kraugerud
NOVA course, June 15, 2009
Department of Animal and Aquacultural Sciences
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment – where to perform
 The pretreatment agents (enzymes, yeast etc.) might be
added before the extrusion line (if not it is not pretreatment)
Bioreactor
Place where
pretreatment
might be
performed.
Flexibility
-Temperature
-Moisture
-Pressure
-pH
-Mixing poss.
Mixer
Incubated
material is
being mixed
with the rest
material that
is not
pretreated
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment of feed sources I
 Historical approach
– What is the old fashion way of pretreatment?
 Humans has pretreated their food for ages
– Kinema in India (Shrestha and Noomhorm, 2001)
• Boiled
• Addition of wooden ash
• Naturally fermented for 24 – 48 h in bamboo baskets
– Main bacteria causing fermentation: Bacillus subtilis
– Natto in Japan, first reported in 1087 AD (Tripathi and
Misra, 2005)
• Fermented by Bacillus natto
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment of feed sources II
 What is pretreatment
– Additional treatment to the feed mash, or parts of it, than
regular milling and conditioning
 Why pretreatment
– Increase nutritional quality
• Is being used if extrusion is not increasing nutritional
value sufficiently.
• If high processed ingredients are too expensive.
(Might be cheaper to do it inhouse)
– If water is added; often cheaper to perfrom it online as to avoid cost of drying process.
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment – methods I
 Biological
– Enzymes
• Singel enzymes
– Phytases
Defined end
products
– Proteases
– Carbohydrases
• Enzyme packages
– Pancreatin
– Microbes/yeast – General increasing the nutritional value
of the feed
• End-product is a mix of onknown products
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment – methods II
 Biological
fermenting agent
– Microbes/yeast/funghis – General increasing the
nutritional value of the feed
• End-product is a mix of unknown components
– Some desirable
– Some undesirable
– Key point:
» Wise choice of fermenting agent
• Pretreatment conditions are crucial for obtaining
reproducable results
– Monitor and specifye
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
CASE 1
Fermentation of rape seed meal and
effect on fish performance.
Exp. 1
Exp. 2
7
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Fermentation of of whole meal flour (WMF)
 Digestibility trial with Atlantic salmon
 Fermentation of wheat or barley
 Inclusion level: 24%
 Fermenting agent: Lactobacillus strain (AD2)
 16 h @ 30°C, 45% moisture
 Chemical composition of
Isolated from
sourdough
diets ~similar
 Extruded diets
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Skrede et al., 2001; 2002
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Fermetation of of whole meal flour (WMF)
● Fermented meal
■ Untreated meal
Skrede et al., 2002
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment – methods III
 Biological
– The fermentor itself contributes to the end product
• Changing the chemical composition of the mash
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment – methods IV
 Chemical
– pH
• Often combined with biological to obtain ideal
working conditions for the enzymes/microbes/yeast.
– Extractions
Not lectured
– Organic acids
– Mechanical
• Grinding – particle size
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Described by
Ozren Z. in
Lecture 4
11
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment – physical properties of the feed
 An experiment with on-line pretreatment
 Aim:
1. Check whether pretreatment itself had any effect on
physical properties of the feed
2. Implement the online pretreatment in a regular
extrusion line
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
On-line Pretreatment
 Processing parameters
Pretreatment
Diet
Conditoined
s.e.m.
Incubated
P
Conditioning
Temperature a (°C)
Extrusion
76
76
0.3
0.7522
1st section
62
63
1
0.2909
3rd section
118 b
121 a
0.7
0.0077
b
a
0.9
0.0111
117
106
116
109
1
2
0.4546
0.2009
4th section cc (bar)
Die (bar)
Screw speed (rpm)
0.55 b
28
273
0.73 a
28
273
0.02
1
0.07
0.0176
0.9239
0.2328
Torque d (Nm)
359 a
338 a
7
0.0433
SME e (Wh/kg)
42 a
39 b
0.8
0.0319
Temperature c (°C)
th
4 section
5th section
Die
Pressure
106
110
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Kraugerud & Svihus; accepted for AFST.
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
On-line Pretreatment
 Physical properties
Preatrement
Diet
Conditioned
34 a
96
26
Incubated
24 b
93
28
Bulk density [g/l]
519 a
Length [mm]
PDI b [%]
Hardness [N]
Durability [%]
Expansion [%]
s.e.m. c
Pc
2
1
2
0.0026
0.0694
0.2195
498 b
5
0.0092
7.7 a
6.5 b
0.1
<0.0001
16.3
15.4
0.3
0.1171
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Kraugerud & Svihus; accepted for AFST.
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment – CASE 2
 Find two practicle challenges/obstacles with pretreatment
 Groups: two and two
 Two minutes
 Group work
– Three groups
– 10 minutes
• Sketch the system (three groups)
• Discuss
– Pros
– Cons
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Pretreatment – literature
Denstadli et al., 2006. Phytate degradation in a mixture of ground wheat and ground defatted soybeans during
feed processing: Effects of temperature, moisture level, and retention time in small- and medium-scale
incubation systems, Journal of Agricultural and Food Chemistry, 54, 5887-5893
Denstadli et al., 2007. A comparison of online phytase pre-treatment of vegetable feed ingredients and phytase
coating in diets for Atlantic salmon (Salmo salar L.) reared in cold water, Aquaculture, 269, 414-46.
Gnanasambandam and Proctor, 1999. Preparation of soy hull pectin, Food Chemistry, 65, 461-467
Huth et al., 2000. Functional properties of dietary fibre enriched extrudates from barley, Journal of Cereal Science,
32, 115-128.
Ibrahim, S. S., Habiba, R. A., Shatta, A. A., & Embaby, H. E., 2002. Effect of soaking, germination, cooking and
fermentation on antinutritional factors in cowpeas. Nahrung-Food 46, 92-95.
Ito, T., Saito, K., Sugawara, M., Mochida, K., & Nakakuki, T., 1999. Effect of raw and heat-moisture-treated highamylose corn starches on the process of digestion in the rat digestive tract. J. Sci. Food Agric. 79, 1203-1207.
Kraugerud and Svihus, accepted. A comparison of online pretreatment of plant feed ingredients on processing
responses and physical properties of extruded fish feed, Animal Feed Science and Technology.
Martin-Cabrejas, M. A., Sanfiz, B., Vidal, A., Molla, E., Esteban, R., & Lopez-Andreu, F. J., 2004. Effect of
fermentation and autoclaving on dietary fiber fractions and anti nutritional factors of beans (Phaseolus
vulgaris L.). J. Agric. Food Chem. 52, 261-266.
Phillips, R. D., Chinnan, M. S., Branch, A. L., Miller, J., & Mcwatters, K. H., 1988. Effects of pretreatment on
functional and nutritional properties of cowpea meal. J. Food Sci. 53, 805-809.
thiamincontent and increased browning of the meal.
Refstie, S., Sahlstrøm, S., Bråthen, E., Baeverfjord, G., & Krogedal, P., 2005. Lactic acid fermentation eliminates
indigestible carbohydrates and antinutritional factors in soybean meal for Atlantic salmon (Salmo salar).
Aquaculture 246, 331-345.
Skrede, G., Storebakken , Skrede , Sahlstrøm, Sørensen, Shearer, Slinde , 2002. Lactic acid fermentation of wheat
and barley whole meal flours improves digestibility of nutrients and energy in Atlantic salmon (Salmo salar L.)
diets, Aquaculture, 210, 305-32.
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Lecture 10. Extrusion and nutritive value
17
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140
Bin
120
100
Temperature [oC]
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
EXTRUSION – energy (heat & mechanical)
Conditioner
80
60
Mash
Cutting
40
0
20
0
Extruder barrel
1
2
3
Extruder section
4
5
Die
1.25 meters
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Printed with permission from Bühler
18 AG
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Starch – effect during extrusion process
Showing disintegrated starch granules
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Animation by Kraugerud, 2008;
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Drawings by Tester et al., 2004
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Shear
Tester et al.,202004
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Starch + proteins + extrusion= possible reactions
 Starch  dextrines and maltose
⇒ sugar with reducing ends
 Proteins  unfolding
– ⇒ ε-amino group of lysin
gets exposed
 Reducing end of sugars react with
ε-amino group of lysin
⇒ reduction of available lysin
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Unfolding of proteins.
● : hydrophobic AA residues
○ : hydrophilic AA residues
s-s : disulphide bonds
Camire et al.,
211991
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Extrusion - effect
 Starch
– Expansion as effect of temperature
Hashimoto & Grossmann, 2003
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 Starch
– Water stability
Protein loss, 1h, 28 degr. [%]
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Extrusion - effect
22
19
16
13
10
Extruded Pea
Raw pea
Extruded canola
Ingredient [30% inclusion]
Cruz-Suarez et al., 2001
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Extrusion – whch parameters to concider
 Temperature
 110 – 150°C
 Moisture
 15 – 60%
 Press
 10-50 bar (at the
 Mechanical energy
(shear)
 Time
die)
 30 – 150 Wh/kg
 10-60s
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Extrusion - effect
 Digestible
– Starch
• Expansion
• Water stability
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
SME & moisture  effect on gelatinisation
Bühler AG, 26
2007
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 CASE
– Fish feed
– 3 T/h
– 28.5% moisture
– Retention time 30 s
Extruder torque [%]
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Condition temperature  effect in extruder
Temperature, conditioner[°C]
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Bühler AG, 27
2007
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Starch: Gelatinisation – T & p
•Low DM (not
comparable to
extrusion)
•Long time (not
comparable to
extrusion)
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Douzals, 2001; J. Agric. Food Chem
28
Extrusion of wheat starch
100
Degreee of gelatinisation[%]
Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Gelatinisation – T, % moisture & shear
90
80
25% 300 rpm
25% 200 rpm
30% 300 rpm
70
30% 200 rpm
60
80
100
120
140
160
180
Barrel Temperature [C]
Here at same temperatures (as the T, P graph), the starch is NOT gelatinised!
Time and water content is also an important factor!
Why the one with higher water content with a lower degree of gelatinisation?
ANSWER: Low moisture  high shear, hence high degree of gelatinisation)
SME when extruding starch: Increase compared with other materials  due to the endotermic
nature of gelatinisation.
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Cai, 1993; Journal of food science
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Simple charts = good charts
Bühler AG, 30
2007
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Type of extruder - possibilities
Twin
Single
co-rotating
(PHYSICAL
(NUTRITIONAL
EFFECT)
FôrTek
Twin
Counter-rotating
EFFECT)
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Lecture 9 and 10, NOVA: Feed Technology and Farm Animal Nutrition , 2009
Extrusion – literature
Dust et al., 2004. Extrusion conditions affect chemical composition and in vitro
digestion of select food ingredients, J. Agric. Food Chem., 52, 2989-2996
General effect of extrusion
Camire et al., 1990. Chemical and Nutritional Changes in Foods during
Extrusion, Critical Reviews in Food Science and Nutrition, 29, 35-57
M.D. Drew, Borgeson, Thiessen, 2007. A review of processing of feed
ingredients to enhance diet digestibility in finfish, Animal Feed Science and
Technology, 138, 118–136
Extrusion and effect on proteins
Areas, J.A.G., 1992. Extrusion of Food Proteins, Critical Reviews in Food
Science and Nultritlon, vol. 32, 4, 365-392.
General overview of feed extrusion
Aldrich, Greg, Riaz, Mian N., 2007. Extruders and expanders in pet food, aquatic and
livestock feeds, Clenze, Agrimedia GmbH.
-Recommended chapters: 8 and 10.
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