Effects of crude, semipurified, and purified starch of sago (Metroxylon sagu Rottb.) on the water stability of pelleted shrimp diets.

Abstract

Three isonitrogenous, isocaloric practical-type diets with purified, semipurified and crude starch from sago palm as binders, were pelleted through a 2-mm diameter die in a Hobart meat grinder, steamed for 5 min at 85 to 90 C and oven-dried to a moisture content of approximately 10%. The pellets were evaluated for water stability after 3, 6 and 21 h in seawater with 32 ppt salinity and 28 C temperature. Approximately equal amounts of the 3 diets remained intact after 3 and 6 h. After 12 h of immersion the pelleted diets decreased significantly in water stability. However, the diet containing semipurified sago starch had the highest water stability (79.1%). The values were nearly the same for the pellets bound with purified and crude sago starch. Purified sago had the highest additional cost per kg of diet (P4.15). The semipurified and the crude sago starch had about the same costs, at P0.17 and P0.135, respectively. Semipurified sago starch, therefore, is preferable to the crude sago starch.