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Raw Materials and Their Impact on the Extrusion of Aqua Feeds

Raw Materials and Their Impact on the Extrusion of Aqua Feeds. Presented by: Brian Plattner, PE Wenger Manufacturing, Inc. Fundamentals of Extrusion Processing. Recipe Hardware Software Product Specifications. Raw Materials.

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Raw Materials and Their Impact on the Extrusion of Aqua Feeds

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  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, 66,768 particles/g **Mean Diameter = 224µm, 519,365 particles/g

  8. Effect of Grind Size on Extruded Feed Processing on X85 System

  9. 2000 120 3.5 g solids 2/64" Grind 1800 25 ml water Temperature 100 1600 1400 80 1200 Temperature (C) Viscosity (cP) 1000 60 40 Mesh Grind 800 40 600 400 20 3/64" Grind 200 0 0 0 200 400 600 800 1000 1200 Time (Seconds) 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. 31 29 27 25 Extrusion Moisture (%) 23 21 19 17 15 10 15 20 25 30 35 40 Vegetable Proteins in Recipe (%) Effect of Vegetable Protein Levels On Extrusion Moisture

  15. Crude Protein (%) Crude Fiber (%) Oil (%) Dehulled Solvent Extracted 49.0 3.3 1.2 Soybean Meal Nutrient Level Comparison • Non-dehulled • Solvent Extracted • 44.0 • 7.0 • 1.2 • Full Fat Soy • 37.5 • 7.4 • 17.4

  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 60°C • 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. Carbohydrate - energy source Assists expansion Improves binding and pellet durability Found in two forms Amylose Amylopectin 10 - 60 % levels in aquatic food STARCH 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. Type Floating Sinking Minimum Starch (%) 20 10 Recommended Starch Levels in Aquatic Feeds

  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. Wheat Corn Waxy Corn High Amylose Corn 31 31 28 34 Minimum Moisture Levels Necessary to Initiate Starch Gelatinization • Starch Source • % Moisture 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 (>40%)

  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 • <7% • 7-12% • 12-17% • Above 17% • Effect on Product Quality • 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 • 0 • 5 • 10 • 15 • % Added • Fat • Bulk Density • (g / l) • 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. 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.

  40. 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

  41. Effect of Extrusion on Microbial Populations • Microbe Raw Recipe After Extrusion TPC (CFU/g) Coli form Mold count Clostridium Listeria Salmonella 240,00 22,600 54,540 16,000 positive negative 9,300 <10 <10 <10 negative negative

  42. 10000 Thermal Plastic Spores E. Coli Salmonella Listeria 1000 Time (Seconds) 100 10 1 30 50 70 90 110 130 150 170 Temperature (C) Thermal Destruction Studies for Pathogenic Organisms

  43. 70 65 60 55 Recovered (%) 50 45 1 40 35 Fumonisin B 30 25 20 140 150 160 170 180 190 200 Extrusion Temperature (C) Effect of Extrusion Temperature on Fumonisin Toxin Levels (Katta, Jackson, Sumner, Hanna, Bullerman, Cereal Chem. 76(1):16-20, 1999)

  44. Effects of Heat Processing on Insect Survival Temperature (°C) Effect >62 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

  45. After Ripening Factor • Biochemical changes occurring after harvest are influenced by storage time.

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

  47. By-Products

  48. 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

  49. 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

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