Characteristics Of Partially Pregelatinized Sago Starch Extruded Under Various Conditions Using A Twin Screw Extruder Without A Die

Abstract

Abstract This study aims to obtain the characteristics of PPSS as a binder extruded in a twin-screw extruder (TSE) without a die under 9 extrusion conditions selected from a systematic review. The Successive conditions: moisture content, last zone of barrel temperature, and screw speed for each condition were recorded. Respectively, the values were 32%, 60⁰C, 100 rpm for PPSS 1; 22%; 120⁰C; 250 rpm for PPSS 2; 22%, 100⁰C, 250 rpm for PPSS 3; 16%, 135⁰C, 150 rpm for PPSS 4; 10%, 160⁰C, 200 rpm for PPSS 5; 28.8%;, 100⁰C, 220 rpm for PPSS 6; 30%, 80⁰C, 200 rpm for PPSS 7; 25.2%, 97.5⁰C, 250 rpm for PPSS 8, and 30%; 135⁰C; 160 rpm for PPSS 9. The study informed that the degree of gelatinization (DG), water solubility index (WSI), water absorption index (WAI), and swelling power (SP) of PPSS 6 were the highest among the others but its bulk density (BD), degree of whiteness (DW), maximum viscosity (MV), and enthalpy were the lowest. Scanning electron microscopy showed that PPSS granules were irregular compared to their natural oval shape. Starch granule crystallinity indicated that some crystallines became amorphous and some increased (PPSS 3 and 4) while birefringence properties almost disappeared entirely.