EFFECTS OF STARCH, LIPID AND MOISTURE CONTENTS ON EXTRUSION BEHAVIOR AND EXTRUDATE CHARACTERISTICS OF RICE-BASED BLENDS PREPARED WITH A VERY-LOW-COST EXTRUDER

摘要

Response surface methodology with a 3×3 factorial plan design was used to investigate the effects of starch content (60-70 g/100 g dry matter [DM]), lipid content (6.2-10.2 g/100 g DM) and moisture content (10-16 g/ 100 g wet matter [WM]) on extrusion behavior of rice-based blends, on the physicochemical properties of extrudates, and the apparent viscosity of resulting gruels. The increase in starch content increased the loss of lipid, the expansion ratio, the degree of gelatinization (DG) of starch, and the water absorption index (WAI). Increasing lipid content resulted in higher loss of lipids and a lower WAI and water solubility index (WSI). Water content had the most influence. Increasing water content resulted in increased loss of lipids, higher moisture content of extrudates, and in lower die temperature, expansion ratio, DG, WAI and WSI. The high DG (≥91%) of all extrudates demonstrated that the very-low-cost extruder manufactured in Vietnam is suitable for the production of ready-to-eat infant flour.