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Starch source, screw configuration and injection of steam into the barrel affect the physical quality of extruded fish feed
Author(s) -
Sørensen Mette,
Nguyen Giao,
Storebakken Trond,
Øverland Margareth
Publication year - 2010
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2009.02346.x
Subject(s) - durability , starch , materials science , polygon (computer graphics) , pellets , pellet , composite material , food science , biology , engineering , mechanical engineering , frame (networking)
This experiment investigated the physical qualities (‘Holmen’ durability; ‘tumbling box’ durability; and pellet strength, length and diameter) of extruded fishmeal‐based feeds produced using different starch sources, screw configurations, with or without steam injected in the barrel. The starch sources tested were native or pre‐gelatinized potato starch (PGS), wheat starch (WS), whole wheat (WW) or a combination of WS and WW. Screw configurations were a polygon element, followed by two left‐pitched segments, Polygon_2L; a polygon, followed by one left‐pitched and one right‐pitched element, Polygon_LR; and no polygon section, alternating left‐ and right‐pitched elements, LRLR. Starch source and screw configuration affected the physical quality the most. Pellets produced with LRLR had the highest ‘Holmen’ durability (76%), hardness (30 N) and the least diameter (5.3 mm). The lowest durability (37%) and hardness (22 N) were obtained with Polygon_LR. Potato starch yielded higher expansion than cereal starch. The highest ‘Holmen’ durability was seen for PGS (79%), while WS yielded the lowest value (44%). Injection of steam reduced hardness and ‘Holmen’ durability, but provided a minor overall contribution to physical quality compared with the starch source and screw configuration. ‘Holmen’ durability appeared to be suitable to unveil variation (37–79%) in physical quality, while ‘Tumbling box’ durability (98.4–98.8%) did not prove efficient.