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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #229725
Title: Twin Screw Extrusion of DDGS-based Aquaculture Feeds

Author
item KANNADHASON, S - SOUTH DAKOTA STATE UNIV
item Rosentrater, Kurt
item MUTHUKUMARAPPAN, K - SOUTH DAKOTA STATE UNIV
item BROWN, MICHAEL - SOUTH DAKOTA STATE UNIV

Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/4/2008
Publication Date: 2/1/2010
Citation: Kannadhason, S., Rosentrater, K.A., Muthukumarappan, K., Brown, M.L. 2010. Twin Screw Extrusion of DDGS-based Aquaculture Feeds. Journal of the World Aquaculture Society. 41(51):1-15.

Interpretive Summary: Distillers dried grains with solubles (also known as DDGS) is a potential protein source for aquaculture feeds, but much work remains in order to effectively process this ingredient into a complete feed. Six feed blends were prepared based on level of DDGS (0, 17.5, 20, 22.5, 25, and 27.5%), and other ingredients (soybean meal, corn, fish meal, whey, soybean oil, vitamin and mineral mix). The blends were balanced to 15% db moisture content, then extruded in a twin screw extruder using a 2 mm die at 190 rpm, and a 3 mm die at 348 rpm. In order to examine the quality of the resulting extrudates, analyses included moisture content, expansion ratio, unit density, bulk density, sinking velocity, color (L*, a*, and b*), water absorption, water solubility, and pellet durability indices. Increasing the DDGS level from 0 to 17.5% db resulted in decreased expansion ratios by 14.8 and 23.5% for the products extruded using a 2 and 3 mm die, respectively. No significant difference in expansion ratio existed for DDGS levels between 17.5 and 27.5% db for either die. The WSI of the extrudates increased (25.2 and 24.0%) as the DDGS increased from 0 to 27.5% db for each die. The 0% DDGS had the highest expansion ratio and the lowest unit density, bulk density, and sinking velocity. The extrudates that contained 20 and 27.5% DDGS had the highest durability and sinking velocity values. Results from this study show the importance of experimentally determining the effects of feed ingredients and process variables when developing aquafeeds from various materials. Even though this study has provided information about extrusion processing of DDGS with feed ingredients, work still remains in order to optimize aquafeeds from this protein source.

Technical Abstract: Six isocaloric (3.65 kilocalories/gram; kcal/g), isonitrogenous (35% dry-basis; db protein), ingredient blends were prepared with 0, 17.5, 20, 22.5, 25, and 27.5% DDGS and other ingredients (soybean meal, corn, fish meal, whey, soybean oil, vitamin and mineral mix). The blends were moisture balanced to 15% db, then extruded in a twin screw extruder using a 2 mm die at 190 rpm, and a 3 mm die at 348 rpm. Analyses of the extrudates included moisture content, expansion ratio, unit density, bulk density, sinking velocity, color (L*, a*, and b*), water absorption, water solubility, and pellet durability indices. Increasing the DDGS level from 0 to 17.5% db resulted in decreased expansion ratios by 14.8 and 23.5% for the products extruded using a 2 and 3 mm die, respectively. No significant difference in expansion ratio existed for DDGS levels between 17.5 and 27.5% db for either die. The WSI of the extrudates increased (25.2 and 24.0%) as the DDGS increased from 0 to 27.5% db for each die. The 0% DDGS had the highest expansion ratio and the lowest unit density, bulk density, and sinking velocity. The extrudates that contained 20 and 27.5% DDGS had the highest durability and sinking velocity values.