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IMPROVING EXTRUSION

FEATURE

WILL FEED PROFIT by Joseph P. Kearns, V.P. Wenger Aquafeed Division, Wenger Manufacturing, Inc.

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color of the ingredient can also indicate the quality with the lighter color protein sources that undergo extraction for the oils removal usually measuring a higher PDI level. Oil or fat levels in ingredients, reviewed as excessive oil or fat, can affect expansion ratios when extruded. Ingredient evaluation and preconditioning The extrusion process itself is designed to consider ingredient possibilities and can handle most of the fluctuations seen in their quality. The initial phase of extrusion is the preconditioning of the raw materials. This is About the author where the ingredients are subjected to steam Joseph P. Kearns is currently the and water input as well as mechanical energy Vice President Aquafeed Div. for inputs. The effect of proper preconditioning Wenger Manufacturing, Inc. Joe is to prepare the material for entry into the received his bachelor’s degree extruder barrel. from Kansas State University in The goal is to have a processed mass where Food Technology Engineering. An every particle in the formula is moistened employee at Wenger since 1974, he and heated evenly. Preconditioner designs has an impressive eight patents for vary and thus the effectiveness should be Wenger, which all regard aquatic scrutinized. The design selected is based feeds and/or machinery associated on the possibility of using high moisture with the production of it. He has ingredients such as fish or animal silage. more than 60 published articles on Higher usage of liquefied ingredients aquatic feeds production advantages requires a conditioner where mixing by extrusion cooking through trade intensity is increased. Lower level usage magazines and has presented at of liquid ingredients generally allow for a countless events around the world on Starch level and protein quality conditioner where increased shear or energy the topic of aquatic feed production. Reviewing ingredient composition shows that input is achieved. a minimum starch level is required for different Tests have shown that conditioners types of aquatic feed. Increased starch is required for the production of floating feeds while lower levels are usually utilizing increased energy input expressed in kilowatt hours/metric acceptable for sinking feeds. The quality of the starch is also a factor ton, is higher and allows for lower steam usage. The product of how low you can go on floating feeds. Corn and wheat starches are actually achieves a higher percentage of cooking at lower moisture generally the most used while tuber starches do give great expansion levels on the low liquid ingredient style formulas. High Intensity Preconditioners allow for elevated liquid inputs resulting in a free ratios. Additionally the protein quality also has an affect on the required flowing homogenous mass directed into the extruder barrel. starch level as the functionality of the protein comes into play. An example is soybean meal, if the soybean meal has a good Protein Single or twin-screw barrels? Dispersibility Index (PDI) generally the starch content of the formula The extruder barrel designs also vary greatly; single and twin-screw may be somewhat reduced. The quality of the soybean meal is greatly styles dominate in the aquatic feed sector. Single screw extruders are affected by the method it is prepared or processed. Lower temperature generally used for high capacity production of selected classes of drying methods after the oil is extracted, yields a higher PDI. The products such as floating feeds for carp, catfish, salmon, sea bass-sea

ngredient quality and cost changes, coupled with the demanding final product characteristics of aquatic feeds, has resulted in the advantage of incorporating controls on extrusion projects resulting in the improvement of the profitability of producing these feeds. Feeds designed to float or sink need to act as intended in either salt or fresh water. Density control along with In-Line measurements allows for monitoring this parameter continuously with computer-controlled adjustments much faster than any extruder operator or lab personnel can do manually. Formulation considerations also play a part as feed formulations are constantly under review or change based on cost and this can be directly associated with profitability. Ingredients vary in many ways such as fiber, protein, starch levels and fat contents to mention a few. The quality of these ingredients can be and are selected based on cost, functionality, and extrudeability. Extrusion cooking systems are available to handle all possibilities. The question is sometimes how can we handle the everyday differences in ingredient selections and the expectations of the process?

18 | January 2017 - International Aquafeed

JAN 2017 - International Aquafeed magazine  
JAN 2017 - International Aquafeed magazine  
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