Influence of alkali concentration on the deproteinization and/or gelatinization of rice starch

Starch was extracted from BR-IRGA110 rice flour using solutions of NaOH at concentrations varying between 0.06% and 0.30% (w/v). The efficiency in protein removal was evaluated using intrinsic fluorescence. In parallel, the morphological changes in starch granules and their partial gelatinization were observed using scanning electron microscopy. The starch crystallinity was monitored by X-ray diffraction and the gelatinization properties were analyzed using differential scanning calorimetry. It was found that the granular organization was significantly altered when the alkaline extraction was conducted with NaOH solutions at concentrations higher than 0.24% (w/v).