Porous rice powder from the precipitation of gelatinized flour or starch paste with ethanol

Hot paste obtained by autoclaving (1308C, 25 psi, 20–30 min) a 5–7% w/w rice flour or starch slurry was precipitated with ethanol (three extractions) to produce a dry, porous, pregelatinized powder with an average particle size of 75.0 mm (flour-derived powder) and 41.6 mm (starch-derived powder). The microstructure of the individual particles was characterized by an interconnecting lattice of irregularly shaped vesicles, and with cavities of varying size and shape. The vesicular network was relatively thinner and finer for the starch-derived products compared with the flour-derived ones. In comparison with native flour and starch, the bulk density of pregelatinized powders decreased; solvent uptake (water, oil, and alcohol), swelling power, and in vitro starch digestibility increased; whereas, gel consistency, freeze–thaw stability, and AAM content sparingly changed. Changes in morphological and physicochemical properties were generally more evident on the starch-derived products compared with the flour-derived counterparts. To some extent, changes in properties were also affected by severity of the gelatinization treatment (varying slurry concentration and autoclaving duration). The pregelatinized rice products as developed may be useful in food and nonfood applications.