Preparation and characterization of octenyl succinic anhydride modified waxy rice starch by dry media milling

Octenyl succinic anhydride (OSA) modified starch from waxy rice was prepared using dry media milling. The characteristics of OSA were investigated by laser particle analyzer, FT-IR spectroscopy, XRD, and DSC. Degree of substitution (DS) and reaction efficiency (RE) were significantly (p<0.05) influenced by sodium hydroxide concentration, OSA concentration, and mechanical activation time. The suitable processing conditions for preparing octenyl succinic anhydride starch (OSA starch) were determined to be 0.9 g sodium hydroxide per 100 g starch, 4 g OSA per 100 g starch, and 20 h of mechanical activation. Intensities of characteristic peaks at 1724 and 1572 cm−1 in FT-IR spectrogram increased with DS, which confirmed the successful introduction of ester carbonyl groups into the starch. Size distribution analysis and XRD indicated that the increased DS and RE by dry media milling were attributed to both the decrease of starch granule size and the destruction of the crystalline structure. DSC results showed that the gelatinization temperature of the OSA starch decreased with the increase of DS.