Raw Materials and Their Impact on the Extrusion of Aqua Feeds

1
Raw Materials and Their Impact on the Extrusion
of Aqua Feeds

Presented by Brian Plattner PE Wenger
Manufacturing Inc.
2
Fundamentals of Extrusion Processing

• Recipe
• Hardware
• Software
• Product Specifications

3
Raw Materials
Raw materials and their characteristics are
always the most important extrusion variable.
4
Particle Size Analysis of Typical Aquatic Feeds
U.S. Standard Sieve
Openings in Microns
Percent on Sieve
20 30 40 50 60 80 Pan
850 600 425 300 250 180 0
1.00 3.00 28.0 29.0 21.0 14.0 4.0
Geometric Mean Diameter 327 Microns Geometric
Standard Deviation 1.58
5
Benefits of Proper Particle Size

• Improved product appearance
• Reduced incidence of die orifices plugging
• Ease of cooking
• Reduced product breakage and fines
• Increased water stability
• Improved retention of liquid coatings due to
  small cell structure

6
Guidelines for Grind of Recipe

• Maximum particle size 1/3 of die opening
• Not to exceed 1.5mm grind

800 micron 1.5 mm
7
Particle Size Analysis of Two Grinding Processes
of Extruded Feed
Mean Diameter 316µm 66768
particles/g Mean Diameter 224µm 519365
particles/g
8
Effect of Grind Size on Extruded Feed Processing
on X85 System
9
Effect of Grind on Floating Aquatic Feed
10
Recipe Preparation

• Grind ingredients to proper particle size
• Weigh individual ingredients
• Particle size and density of each ingredient
  should be similar
• Premix by hand the micro-ingredients (anything
  less than 1 of total recipe) and add a carrier
  (part of a major ingredient) if necessary to
  bring premix size up to 3 of total recipe
• Add major ingredients then premix (from 4) to
  mixer and mix 3-5 minutes. Add any liquids
  slowly and then mix another 3-5 minutes
• Final grind if required
• Use sifter and/or magnet to detect and remove
  foreign material

11
PROTEIN

• Plant Sources
• Soy Legumes Wheat/corn glutens cereal grains
• Good functional properties
• Lower cost
• Amino acid profile may require supplementation
• Animal or Marine Sources
• Meat Fish Poultry Blood Gelatin
• Poor functional properties unless fresh or spray
  dried
• Higher costs
• Good amino acid profile

12
Vegetable Proteins in Salmon Trout and Shrimp
Diets
Hardy (January 1999) Feed Management Magazine
13
Benefits of Vegetable Proteins in Aquatic Diets

• More expansion potential for floating diets
• More binding potential for improved durability
• Reduced ingredient costs
• Lower incidence of white mineral deposits in
  screw and die area
• Higher oil absorption levels possible in coating
  operations
• Reduce dependence on fish meal

14
Effect of Vegetable Protein Levels On Extrusion
Moisture
15
Soybean Meal Nutrient Level Comparison

• Dehulled
• Solvent Extracted
• 49.0
• 3.3
• 1.2

Non-dehulled Solvent Extracted 44.0 7.0 1.2
Full Fat Soy 37.5 7.4 17.4

• Crude Protein ()
• Crude Fiber ()
• Oil ()

16
Addition of Slurries to Extrusion System

• Maximum particle size not to exceed 1.5 mm
• Fish ensilage slurries pumped into DDC
• Fat/oil slurries heated to 60C
• Moisture is limiting factor for most slurry
  additions
• Enzyme treatments reduce viscosity

17

Wet slurries pumped into DDC preconditioner and
extruder barrel (head 2)
18
Positive Displacement Wet Slurry Pump System
slaved to Dry Recipe Rate
19
Maximum Wet Slurry Addition to Single Screw
Extrusion Systems
Maximum moisture addition to Single Screw
Systems is 16.7
20
Maximum Meat Addition to Twin Screw Extrusion
Systems
Maximum moisture addition to Twin Screw Systems
is 20.0
21

• Protein denatures at 60 - 700C
• As protein denatures it becomes insoluble
  (non-functional)
• Starch gelatinizes at 55 - 750C
• As starch gelatinizes it becomes soluble

22
STARCH

• Carbohydrate - energy source
• Assists expansion
• Improves binding and pellet durability
• Found in two forms
• Amylose
• Amylopectin
• 10 - 60 levels in aquatic food

Raw potato starch magnified 450 X
23
Effect of Extrusion on Starch

• Gelatinizes starch
• Improves digestibility in most species
• Forms starch-lipid complexes
• Increases binding characteristics
• Increases susceptibility to enzyme hydrolysis

24
Recommended Starch Levels in Aquatic Feeds

• Type
• Floating
• Sinking

• Minimum Starch ()
• 20
• 10

25
Starch Content of Common Cereal Grains
Cereal Grain Corn Winter Wheat Sorghum Barley
Oats Unpolished Rice
Starch (Dry Basis) 73 65 71 60 45 75
26
Heat of Gelatinization for Various Starches
Heat of Gelatinization (cal / gram)
Starch Source
Size (microns)
Amylose Content ()
High Amylose Corn Potato Tapioca Wheat Waxy Corn
7.6 6.6 5.5 4.7 4.7
55 20 22 28 0
5-25 15-121 5-35 1-35 5-25
27
Minimum Moisture Levels Necessary to Initiate
Starch Gelatinization
Starch Source
Moisture

• Wheat
• Corn
• Waxy Corn
• High Amylose Corn

• 31
• 31
• 28
• 34

Lower moistures during extrusion require higher
extrusion temperatures to achieve same level of
cook.
28
Rice as a Starch Source

• Small tightly packed starch granules that
  hydrate slowly
• Becomes sticky when it gelatinizes
• Choose long grain varieties over medium and short
  grain varieties as they are much less sticky when
  cooked
• Rice is very digestible even when cook values are
  low
• Rice bran may contain up to 40 starch

29
Corn as a Starch Source

• Good expansion
• Excellent binding
• Sticky at high levels (gt40)

30
Wheat as a Starch Source

• Good binding
• Good expansion
• Can be sticky if overcooked
• Contains gluten (good binder)
• Most widely available starch source
• Often utilized as wheat flour which has most of
  the bran removed

31
Tubers as a Starch Source(Potato Cassava)

• Excellent binding (at 5 levels)
• Requires less total starch in diet
• Good expansion
• Often precooked
• Smooth pellet surface
• Increased cost

32
Effect of Extrusion on Starch

• Process
• Raw Recipe
• Preconditioner
• Extruder
• Dryer

Cook 15.5 31.6 92.8 96.7
33
Purposes of Fat in Feeds

• Energy Source
• Increases Palatability
• Provides Essential fatty acids
• Carrier for Fat Soluble Vitamins

34
Fat Sources

• Animal Fat
• Poultry Fat
• Marine Oils
• Blended Animal and Vegetable Fats
• Feed Grade Vegetable Fats

Must use FAH (fat acid hydrolysis) method for
determining fat levels in extruded products.
35
Effect of Fat Levels on Product Quality (Single
Screw Systems)
Level of Fat in Extruded Mix
Effect on Product Quality

• lt7
• 7-12
• 12-17
• Above 17

Little or no effect For each 1 of Fat Above 7
the final bulk density will increase 16
g/l Product will have little or no expansion but
will retain some durability Final product
durability may be poor
Add 5 to above figures for twin screw systems
36
Effect of Internal Levels of Fat on Expansion of
Extruded Feeds
Added Fat
Bulk Density (g / l)

• 0
• 5
• 10
• 15

256 309 408 533
37
Internal Fat vs. Pellet Durability
75
)
70
2
65
60
55
Maximum Compressive Stress (g / mm
50
45
40
35
30
6
8
10
12
14
16
18
20
22
24
26
28
30
Internal Fat ()
38
To Maximize Fat Inclusion Levels

• Formulate with ingredients high in indigenous
  fats (example flax meal)
• Heat fats to 40 - 600C prior to inclusion
• Add late in the process
• Maintain starch / function protein levels
• Increase thermal and/or mechanical energy inputs
• Increase moisture levels during extrusion

39
(No Transcript)
40
Vitamin Pigment Retention

• Vitamin/Pigment Retention Depends On
• Raw material formulation
• Temperature
• Moistures
• Retention times

An average of 10 to 15 percent of vitamins and
pigments are lost during extrusion. Compensation
is made by overages. Heat stable forms are
preferred.
41
Preservation System Required for Soft Moist
Aquatic Feeds (Final product moisture of 16-28)

• Lower Aw (water activity) below 0.70 with
  humectants at 10-12 levels
• Reduce pH to 4.0 - 4.5 with acids at 1-2 levels
  or with fish silage/solubles
• Add mold inhibitors at 0.2-0.5 levels

42
Effect of Extrusion on Microbial Populations

• Microbe

Raw Recipe
After Extrusion
24000 22600 54540 16000
positive negative
9300 lt10 lt10 lt10 negative negative
TPC (CFU/g) Coli form Mold
count Clostridium Listeria
Salmonella
43
Thermal Destruction Studies for Pathogenic
Organisms
44
Effect of Extrusion Temperature on Fumonisin
Toxin Levels
(Katta Jackson Sumner Hanna Bullerman Cereal
Chem. 76(1)16-20 1999)
45
Effects of Heat Processing on Insect Survival
Temperature (C)
Effect
gt62 50-60 45-50 30-35 25-32
Death in less than 1 minute Death in less than 1
hour Death in less than 1 day Max temperature for
reproduction Optimum for development
Feed Management January 2001 Vol. 52 No. 1 pg
27
46
After Ripening Factor

• Biochemical changes occurring after harvest are
  influenced by storage time.

47
By-Products

• Starch / Filler Sources
• Wheat Bran
• Wheat Midds (Pollards)
• Rice Bran
• Protein Sources
• Co-Products such as DDGS

48
By-Products
49
Effects of Adding Rework to Recipe (5 to 10
percent levels)

• Darker color
• Less expansion higher bulk density
• Higher levels of cook
• More defined shape

50
Better Shape Definition
Bulk Density
Product Hardness
Smooth Skin
More Uniform
RECIPE

• Starch
• Oil (Internal)
• Fiber
• Functional Protein
• Non-Functional Protein
• Rework

- -
- - - -
(1) (2)


(1) Function of grind and particle size (2)
Large cell structure