가교화 후 하이드록시프로필화한 복합변성 쌀전분의 이화학적 특성

Physicochemical properties of dual-modified rice starches, cross-linked (with POCl₃) and hydroxypropylated (with propylene oxide) rice starches, were studied. Rice starch was cross-linked using POCl₃ (0.005%, 0.02% (v/w)) at 45°C for 2 hr and then hydroxypropylated using propylene oxide (2%, 6%, 12% (v/w)) at 45°C for 24 hr, respectively. Swelling power, solubility, thermal properties (DSC) and pasting properties (RVA) of cross-linked and hydroxypropylated (CLHP) rice starches were determined. Swelling power of CLHP rice starch increased at relatively lower temperature than native rice starch. Solubility of CLHP rice starch was lower than that of native rice starch. Peak viscosity of CLHP rice starch was lower than that of native starch while holding strength and final viscosity were increased with modification. Breakdown value was lower and setback value was higher than native rice starch. DSC thermal transitions of CLHP rice starch shifted toward lower temperature. Amylopectin-melting enthalpy of CLHP rice starch decreased, whereas it was not affected by the amount of POCl₃.