Ingredient Selection and Extrusion Parameters for Aquatic Feeds June 9, 2015 Cologne, Germany Joseph P Kearns VP Aqua-Feed Div. Wenger MFG. Sabetha, Kansas USA jkearns@wenger.com
Many Types of Aquatic Feeds, Floating, Sinking with wide ranges of diameters.
Ingredients in General Selected for their Nutritional Value, Cost and/or benefit for the formula Requires proper grinding, mixing etc. for the feed being produced Delivered to the extruder in good order. Usually no situations occur but???? Something is wrong the feed is not coming out as planned. A bit of history:
Flow Index Test for Fish Meals Indicates difficulty in processing fish meal recipes Quality control of incoming raw materials Flow # > 5 cm Poor flowing properties (high internal friction) Harder to cook. Flow # < 2 cm Good flowing properties (low internal friction) Easier to cook. One of the first indications ingredient quality was important. Salmon industry back when high fishmeal diets were produced. As much fishmeal as you can achieve with the lowest starch level in the formula.
1) Plant Sources Protein Soy, Legumes, Wheat/corn glutens, cereal grains Good functional properties Lower cost Amino acid profile may require supplementation 2) Animal or Marine Sources Meat, Fish, Poultry, Blood, Gelatin Poor functional properties unless fresh or spray dried Higher costs Good amino acid profile 5/21/15 from Aquafeed.com fishmeal cost down slightly to right at 1500.00 US/ ton
Benefits of Vegetable Proteins in Aquatic Diets 1) More expansion potential for floating diets 2) More binding potential for improved durability 3) Reduced ingredient costs 4) Lower incidence of white mineral deposits in screw and die area 5) Higher oil absorption levels possible in coating operations 6) Reduce dependence on fish meal With variances seen in plant protein ingredient quality this needs to be understood when purchasing ingredients.
Extruded Floating and Sinking Diets Containing High Levels of Vegetable Protein and Good Water Stability Made from base recipe containing 70% soybean meal, 20% wheat flour, and 10% fish meal. 494 g/l product density After coating, these products contained 22% fat and 35.5% protein 750 g/l product density
Vegetable Protein Sources with Substantial Starch Contributions Faba Bean Lupin Field Peas Component Protein Fat Fiber Starch % 17 30 0.5 3.5 5.0 6.0 35-50
Solubility Comparison of Animal Proteins Spray-Dried Blood Hemoglobin Ring-Dried Blood Meal
% Soluble Protein % Heat Damaged Protein Processing Temperature
Processing Effects on Proteins: Wet Chemistry Methods 1) Denaturation of Proteins - Begins to occur at 55 C ( 130 F) - Measure PDI (Protein Dispersibility Index) digestible in acidic environment 2) Heat- Damaged Proteins (poor digestibility) - Can begin at 150 C ( 302 F) - Measure N 2 in acid detergent fiber fraction - Poor digestion in acidic environment
Effect of Raw Material Protein Quality 7 PDI 12 PDI 30 PDI 54 PDI Very Dark Soy Proteins used for FEED (Soybean Meal) PRODUCT COLOR Soy Proteins used for FOOD (Flour, concentrate, isolate) Very Light
Temperature (Celsius) Comparison of Protein and Starch Flow Curves 180 160 RL-100 Rice Flour SBM and some starches are harder to cook then fish meal. Chart shows higher temperature and water are needed. 140 120 100 80 60 Fish Meal #1 Fish Meal #2 Soy Bean Meal 40 20 0 5 10 15 20 25 30 Moisture Content (% wb)
Protein denatures at 60-70 0 C As protein denatures, it becomes insoluble (non-functional) Starch gelatinizes at 55-75 0 C As starch gelatinizes, it becomes soluble Raw After Extrusion Raw After Extrusion Starch Protein
SBM, JPK plant visit
DDGS, JPK Plant Visit
Protein Source Samples in Meeting
Quick test, placed in water and let s see what they do, predicted they would sink and not soften quickly and act like sand. Client called my bluff, brought in samples and water. By no means is this test conclusive. Lab test suggested.
Laboratory Tests to Indicate Protein Functionality 1) PDI (Protein Dispersibility Index) 2) NSI (Nitrogen Solubility Index) These are a measure of the protein s solubility in water and are indicative of the level of heat treatment. The PDI test is a more rapid test and will usually give slightly higher results.
Crown Iron Works Down Draft Desolventiser for High PDI Soya Flakes are handled gently throughout the process, producing a final product with a maximum amount of whole flakes and a minimum amount of fines. Higher attainable PDI than with conventional systems (potentially 80-85). Flexibility in operation to fine tune the system for the ideal combination of PDI, residual hexane, and steam consumption.
Extrusion Moisture (%) Effect of Vegetable Protein Levels On Extrusion Moisture 31 29 27 25 23 21 19 17 15 10 15 20 25 30 35 40 Vegetable Proteins in Recipe (%)
Specific Mechanical Energy (kw-hr / mton) Effect of Protein on SME 75 65 55 45 35 25 Density was kept constant at 520 g / l off of the extruder 15 0 20 40 60 80 100 120 % of Protein from Soy
True Costs should be calculated: If higher temperatures, better starch sources and more water are needed to cook lower grade raw materials then how much does it cost to extrude and dry these ingredients over purchasing a better quality ingredient. The calculations can be made to see the best most cost effective approach. Higher temperatures and more water usually mean lower capacity as well as higher energy use.
The 4 Rules of Extrusion Cooking 1. Raw Materials, including quality specs. 2. Hardware arrangement 3. Running Conditions or software requirements 4. Finished Product Specifications
Ingredients in General Selected for their Nutritional Value, Cost and/or benefit for the formula Requires proper grinding, mixing etc. for the feed being produced Delivered to the extruder in good order. Usually no situations occur but???? Something is wrong the feed is not coming out as planned. A bit of history:
What would be a benefit for the formula? Many aquatic feeds do not need ultra high protein levels. When this is the case and it is easy to get to the desired levels then a benefit is something cheap and readily available. Whatever it is it USUALLY has a high level of FIBER Reporting in on High fiber Aquatic Feeds
Research Objectives Establish limiting factors to high quality production of floating aquatic feeds with low cost nonfunctional ingredients Identify ideal processing parameters for rate and quality optimization Identify ideal screw profile and die set-up for rate and quality optimization Target lower SME production to reduce impact on tooling wear Evaluate the impact of HIP on performance/quality Evaluate the impact of dry ration grind size
Product Quality/Performance Targets 100% Floating < 10% Coefficient of variation for uniformity > 4 hr. Water stability > 95% Pellet durability > 85% Starch gelatinization < 25 kwhr/ton SME
Testing Summary/Results Performed 65 separate tests Grind size matters Fine grind significantly outperforms coarse grind: Minimum 1.4 times more rate 10-20% improvement in uniformity CV 10-15% reduction in SME Fine Grind = Minimum 80% through a US 40 sieve (400 micron) and 20% through a US 20 sieve (841 micron) and over a US 40 sieve (400 micron) Micron Sieve US % Over Sieve 841 20 0% 400 40 20% Pan Pan 80%
Product Quality 100% Floating < 7.5% CV on uniformity > 4 hr. Water Stability > 96% Pellet durability > 85% Starch cook SME = 22 25 kwhr/ton